Laminate of inorganic substrate / polymer film layer with protective film, stack of laminate, method for storing laminate, and method for transporting laminate.

Abstract

An inorganic substrate / polymer film laminate with an attached protective film that allows for easy individual removal even when stored in a stacked state for a long period of time is provided.　A first laminate is characterized by including an inorganic substrate, a polymer film layer and a first protective film, in that order, wherein the surface roughness Ra of the surface of the inorganic substrate opposite of the polymer film layer is 0.02-1.2 μm.

Description

Technical Field

[0001] The present invention relates to a form, a storage method, and further a transportation method when storing a laminate of an inorganic substrate and a polymer film layer.

Background Art

[0002] The use of polymer films such as polyimide has been studied as a substrate material for manufacturing flexible electronic devices. Since such polymer films such as polyimide are manufactured in the form of long rolls, generally in the manufacture of flexible devices, a roll-to-roll manufacturing line is considered ideal. On the other hand, many conventional electronic devices such as display devices, sensor arrays, touchscreens, and printed wiring boards use rigid substrates such as glass substrates, semiconductor wafers, or glass fiber-reinforced epoxy substrates, and the manufacturing apparatus is also configured on the premise of using such rigid substrates.

[0003] From such a background, as a method for manufacturing a flexible electronic device using an existing manufacturing apparatus, a rigid inorganic substrate such as a glass substrate is used as a temporary support, and the polymer film is temporarily attached to the temporary support and handled, and after performing electronic device processing on the polymer film, the polymer film on which the electronic device is formed is peeled off from the temporary support. A method for manufacturing a flexible electronic device by such a procedure is known. (Patent Document 1)

[0004] Also, as a method for manufacturing a flexible electronic device using an existing manufacturing apparatus, a rigid substrate such as a glass substrate is used as a temporary support, a polymer solution or a polymer precursor solution is applied to the temporary support, dried to form a precursor film, and then a chemical reaction is caused to convert the precursor into a polymer film. Thus, a laminate of a temporary support and a polymer film is obtained, and similarly, after forming an electronic device on the polymer film, it is peeled off to manufacture a flexible electronic device. A method for manufacturing a flexible electronic device is known. (Patent Document 2)

[0005] Incidentally, in the process of forming a desired functional element on a laminate formed by bonding a polymer film and an inorganic support, the laminate is often exposed to high temperatures. For example, the formation of functional elements such as polysilicon and oxide semiconductors requires processes in the temperature range of approximately 200°C to 600°C. Furthermore, in the fabrication of hydrogenated amorphous silicon thin films, temperatures of approximately 200°C to 300°C may be applied to the film, and heating to approximately 450°C to 600°C may be necessary to heat and dehydrogenate amorphous silicon to produce low-temperature polysilicon. Therefore, the polymer film constituting the laminate needs to have heat resistance, but in reality, there are only a limited number of polymer films that can withstand such high temperatures, and polyimide is often chosen.

[0006] In other words, both methods involve a laminate in which a rigid temporary support is superimposed with a polymer film layer that is ultimately peeled off and becomes the substrate for a flexible electronic device. Since such a laminate can be handled as a rigid plate material, it can be handled in the same way as a glass substrate using equipment for manufacturing liquid crystal displays, plasma displays, or organic EL displays that use conventional glass substrates. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 5152104 [Patent Document 2] Patent No. 5699606 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The subject of this invention is the form, storage method, and transportation method for a laminate consisting of the polymer film and rigid temporary support described above. Conventional rigid inorganic substrates, such as glass substrates, are handled in stacks of multiple sheets during storage or transportation. When stacking, cushioning materials such as foamed polymer sheets or paper are placed between the inorganic substrates to facilitate removal from the stack after storage or transportation. While this method is applicable to glass substrates with sufficient surface hardness, in the case of laminates of inorganic substrates (temporary support substrates) and polymer films handled by the present invention, the surface hardness of the polymer film is insufficient. Therefore, when the laminates are stacked, the polymer film surface and the inorganic substrate surface rub against each other, causing scratches on the soft polymer film surface. Furthermore, even when cushioning materials such as foamed polymer sheets or paper are included, scratches are easily caused on the polymer film surface due to foreign matter mixed in.

[0009] A common method used to solve these problems is to protect the polymer film surface with a protective film. Generally, the protective film is a low-tack film made by applying a weakly adhesive material to one side of a relatively inexpensive polymer film such as polyethylene, polypropylene, or polyester.

[0010] By using such a protective film, scratches on the polymer film surface are prevented, making it possible to maintain a polymer film surface suitable for forming fine, flexible electronic devices. However, the inventors faced the problem that when multiple laminates with protective films attached to the polymer film surface of the laminate are stacked and stored or transported, the protective film surface and the inorganic substrate surface stick together, making it difficult to remove them individually. Although it is possible to use cushioning materials such as foamed polymer sheets or paper in combination, as with glass substrates, this would require the use of additional auxiliary materials in addition to the protective film, resulting in higher costs and increased waste, so the use of cushioning materials is not a preferred method.

[0011] Furthermore, when a laminate is manufactured by applying a polymer solution or polymer precursor solution to an inorganic substrate and converting it into a polymer film, the laminate manufacturing process is a batch process. However, considering productivity in subsequent processes, it is preferable that the laminate be in the form of a continuous sheet by joining together individual laminates. To prevent scratches on the polymer film surface and improve transportability, a long protective film can be continuously attached to the polymer film surface of the laminate, as shown in Figure 1, allowing the individual laminate to be treated as a continuous sheet. In this case, the laminate may be stored and transported in a stacked state with the protective film folded, as shown in Figure 2, but even then, the protective film surface and the inorganic substrate surface may stick together.

[0012] Furthermore, from the perspective of preventing scratches on the glass, a protective film may be applied to the inorganic substrate surface in both cases where a polymer solution or polymer precursor solution is used, and when a pre-filmed polymer is used. In such cases, the protective film may be stored and transported in a folded stack state as shown in Figure 3, but this also presents the problem of the protective film surface and the inorganic substrate surface sticking together.

[0013] The problem to be solved by the present invention is to provide an appropriate form and method for storing or transporting a laminate consisting of a polymer film and a rigid temporary support. In other words, the present invention provides an inorganic substrate / polymer film laminate with a protective film that can be easily removed individually even when stored in a stacked state for a long period of time, a stack of inorganic substrate / polymer film laminates with protective films, a method for storing inorganic substrate / polymer film laminates using a specific protective film, and a method for transporting inorganic substrate / polymer film laminates. [Means for solving the problem]

[0014] In other words, the present invention consists of the following configuration. [1] A first laminate comprising an inorganic substrate, a polymer film layer, and a first protective film in that order, characterized in that the surface roughness Ra of the side of the inorganic substrate opposite to the polymer film layer is 0.02 μm to 1.2 μm. [2] The first laminate according to [1], characterized in that the coefficient of dynamic friction between the surface of the first protective film opposite to the polymer film layer and the surface of the inorganic substrate opposite to the polymer film layer is in the range of 0.02 to 0.25. [3] A second laminate comprising a second protective film, an inorganic substrate, a polymer film layer, and a first protective film in this order, characterized in that the surface roughness Ra of the side of the second protective film opposite to the inorganic substrate is 0.02 μm to 1.2 μm. [4] The second laminate according to [3], characterized in that the coefficient of dynamic friction between the surface of the first protective film opposite to the polymer film layer and the surface of the second protective film opposite to the inorganic substrate is in the range of 0.02 to 0.25. [5] The second laminate according to [3] or [4], characterized in that the coefficient of dynamic friction between the faces of the second protective film opposite to the inorganic substrate is in the range of 0.02 to 0.25. [6] The laminate according to any one of [1] to [5], characterized in that the diameter of the circumscribed circle of the inorganic substrate is 310 mm or more. [7] A laminate stack characterized by stacking four or more laminates described in any of [1] to [6] in the same orientation in the layer direction. A method for storing laminates, characterized by storing them in the form of a laminate stack as described in [8] [7]. A method for transporting laminates, characterized by transporting them in the form of a laminate stack as described in [9] [7]. [Effects of the Invention]

[0015] In a laminate of an inorganic substrate processed into a continuous sheet shape with a protective film and a polymer film, if the outer surface of the inorganic substrate opposite the polymer film is smooth when the second protective film is not used, or if the surface of the second protective film is smooth when the second protective film is used, when the laminate is packed in a stacked state and stored for a long period of time, the air layer between the surface facing the first protective film is gradually expelled from between the surfaces due to the weight of the laminate, resulting in a vacuum-sealed state. This is why it becomes difficult to remove the laminates individually after long-term storage. This is not a major problem when the size of the laminate is small, but when considering handling in display manufacturing equipment, the size of the inorganic substrate in the laminate can be up to about 2m x 3m. When multiple laminates of this size become vacuum-sealed, it becomes extremely difficult to separate them, and if the inorganic substrate is glass, damage to the glass substrate is also likely to occur. By adopting the configuration of the present invention, such problems can be avoided, and even when the laminate and protective film-containing laminate of the present invention are packed in a stacked state and stored for a long period of time, they can be easily removed individually. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1(a) shows an example of the process for a first laminate, in which a polymer solution or polymer precursor solution 11 is coated onto an inorganic substrate 12 to create an inorganic substrate 12 / polymer film layer 15 laminate, and then processed into a continuous sheet shape by attaching a first protective film 14 to the surface of the polymer film layer 15. Figure 1(b) shows an example of the process for a second laminate, in which a polymer solution or polymer precursor solution 11 is coated onto an inorganic substrate 12 to create an inorganic substrate 12 / polymer film layer 15 laminate, and then processed into a continuous sheet shape by attaching a first protective film 14 and a second protective film 16 to the surface of the polymer film layer 15. [Figure 2] Figure 2 is a schematic diagram showing the cross-sectional structure of a stack of four first laminates (first protective film 23 / polymer film layer 22 / inorganic substrate 21) stacked on top of each other. The laminates form a continuous sheet and are folded one by one. [Figure 3] FIG. 3 is a schematic diagram showing a cross-sectional structure of a stack in which four second laminates (first protective film 33 / polymer film layer 31 / inorganic substrate 32 / second protective film 34) are stacked. The laminate containing the protective film is in the form of a continuous sheet and is folded for each laminate. [Figure 4] FIG. 4 is a schematic diagram showing a cross-sectional structure of a stack in which four second laminates (first protective film 43 / polymer film layer 42 / inorganic substrate 41 / second protective film 44) are stacked. [Figure 5] FIG. 5 is a schematic diagram for explaining a method of applying a silane coupling agent according to the present patent.

Mode for Carrying Out the Invention

[0017] Hereinafter, an embodiment of the present invention (hereinafter abbreviated as "embodiment") will be described in detail. Note that the present invention is not limited to the following embodiments and can be variously modified and implemented within the scope of the gist thereof.

[0018] <Polyamic acid> The polyamic acid in the present invention can be produced by a known production method. That is, one or more tetracarboxylic acid anhydride components and one or more diamine components as raw materials are used and polymerized in an organic solvent to obtain a polyamic acid solution. Preferred solvents for synthesizing polyamic acid are amide solvents, namely N,N-dimethylacetamide, N-methyl-2-pyrrolidone, etc., and N,N-dimethylacetamide is particularly preferably used. The reaction apparatus preferably includes a temperature adjustment device for controlling the reaction temperature. The reaction temperature is preferably 0°C or higher and 80°C or lower, and more preferably 15°C or higher and 60°C or lower because it suppresses the hydrolysis of polyamic acid, which is the reverse reaction of polymerization, and the viscosity of polyamic acid tends to increase.

[0019] There are no particular restrictions on the diamines that constitute the polyamic acid; aromatic diamines, aliphatic diamines, alicyclic diamines, etc., commonly used in polyimide synthesis can be used. From the viewpoint of heat resistance, aromatic diamines are preferred. Diamines may be used individually or in combination of two or more types.

[0020] There are no particular limitations on the diamines used; examples include oxydianiline (bis(4-aminophenyl) ether) and paraphenylenediamine (1,4-phenylenediamine).

[0021] As tetracarboxylic acids constituting polyamic acids, aromatic tetracarboxylic acids (including their acid anhydrides), aliphatic tetracarboxylic acids (including their acid anhydrides), and alicyclic tetracarboxylic acids (including their acid anhydrides), which are commonly used in polyimide synthesis, can be used. When these are acid anhydrides, there may be one or two anhydride structures in the molecule, but those having two anhydride structures (dianhydrides) are preferred. Tetracarboxylic acids may be used individually or in combination of two or more types.

[0022] There are no particular limitations on the tetracarboxylic acid, and examples include pyrrolimetic acid dianhydride and 3,3',4,4'-biphenyltetracarboxylic acid dianhydride.

[0023] The thermosetting product of polyamic acid is preferably a polyimide, and may also be a colorless, transparent polyimide.

[0024] This section describes a colorless, transparent polyimide, which is an example of a thermoset polyamic acid in the present invention. To avoid complexity, it will also be simply referred to as transparent polyimide below. The transparency of the transparent polyimide is preferably such that the total light transmittance is 75% or higher. More preferably it is 80% or higher, even more preferably 85% or higher, even more preferably 87% or higher, and particularly preferably 88% or higher. While there is no particular upper limit to the total light transmittance of the transparent polyimide, it is preferably 98% or lower, and more preferably 97% or lower, for use as a flexible electronic device. In the present invention, a colorless, transparent polyimide is preferably a polyimide with a total light transmittance of 75% or higher.

[0025] The aromatic tetracarboxylic acids used to obtain the colorless and highly transparent polyimide in the present invention may be used alone or in combination of two or more. When heat resistance is important, the copolymerization amount of aromatic tetracarboxylic acids is preferably 50% by mass or more of the total tetracarboxylic acids, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may even be 100% by mass.

[0026] Alicyclic tetracarboxylic acids include 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, 1,2,3,4-cyclohexanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,3',4,4'-bicyclohexyltetracarboxylic acid, bicyclo[2,2,1]heptane-2,3,5,6-tetracarboxylic acid, bicyclo[2,2,2]octane-2,3,5,6-tetracarboxylic acid, and bicyclo[2,2,2]octo-7-ene-2,3,5,6-tetracarboxylic acid. Bonic acid, tetrahydroanthracene-2,3,6,7-tetracarboxylic acid, tetradecahydro-1,4:5,8:9,10-trimethanoanthracene-2,3,6,7-tetracarboxylic acid, decahydronaphthalene-2,3,6,7-tetracarboxylic acid, decahydro-1,4:5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic acid, decahydro-1,4-ethano-5,8-methanonaphthalene-2,3,6,7-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane -5,5'',6,6''-tetracarboxylic acid (also known as "norbornane-2-spiro-2'-cyclopentanone-5'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid"), methylnorbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-(methylnorbornane)-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclohexanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid (also known as "norbornane-2-s Pyrro-2'-cyclohexanone-6'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid), methylnorbornane-2-spiro-α-cyclohexanone-α'-spiro-2''-(methylnorbornane)-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclopropanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclobutanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cycloheptanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclooctanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclononanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclodecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cycloundecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclododecanone-α'-spiro-2''-norbornane-5,5'' Examples include tetracarboxylic acids such as ,6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclotridecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclotetradecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentadecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-(methylcyclopentanone)-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, and their acid anhydrides. Among these, dianhydrides having two acid anhydride structures are preferred, and in particular, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclohexanetetracarboxylic acid dianhydride, and 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride are preferred, and 1,2,3,4-cyclobutanetetracarboxylic dianhydride is even more preferred. These may be used individually or in combination of two or more. When transparency is important, the copolymerization amount of alicyclic tetracarboxylic acids is preferably 50% by mass or more of the total tetracarboxylic acids, more preferably 60% by mass or more, even more preferably 70% by mass or more, still even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and 100% by mass is also acceptable.

[0027] Examples of tricarboxylic acids include aromatic tricarboxylic acids such as trimellitic acid, 1,2,5-naphthalene tricarboxylic acid, diphenyl ether-3,3',4'-tricarboxylic acid, and diphenyl sulfone-3,3',4'-tricarboxylic acid, or hydrogenated versions of the above aromatic tricarboxylic acids such as hexahydrotrimellitic acid, alkylene glycol bistrimellitates such as ethylene glycol bistrimellitate, propylene glycol bistrimellitate, 1,4-butanediol bistrimellitate, and polyethylene glycol bistrimellitate, and their monoanhydrides and esterified products. Among these, monoanhydrides having one acid anhydride structure are preferred, and trimellitic anhydride and hexahydrotrimellitic anhydride are particularly preferred. These may be used individually or in combination.

[0028] Examples of dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and 4,4'-oxydibenzenecarboxylic acid, or hydrogenated versions of the above aromatic dicarboxylic acids such as 1,6-cyclohexanedicarboxylic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, heptanediic acid, octanedioic acid, azelaic acid, sebacic acid, undecadioic acid, dodecanediic acid, 2-methylsuccinic acid, and their acid chlorides or esters. Among these, aromatic dicarboxylic acids and their hydrogenated versions are preferred, with terephthalic acid, 1,6-cyclohexanedicarboxylic acid, and 4,4'-oxydibenzenecarboxylic acid being particularly preferred. Dicarboxylic acids may be used individually or in combination.

[0029] The diamines or isocyanates used to obtain the colorless and highly transparent polyimide in the present invention are not particularly limited, and aromatic diamines, aliphatic diamines, alicyclic diamines, aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, etc., which are commonly used in polyimide synthesis, polyamide-imide synthesis, and polyamide synthesis, can be used. From the viewpoint of heat resistance, aromatic diamines are preferred, and from the viewpoint of transparency, alicyclic diamines are preferred. Furthermore, using aromatic diamines having a benzoxazole structure makes it possible to achieve high heat resistance, high modulus of elasticity, low thermal shrinkage, and a low coefficient of linear expansion. Diamines and isocyanates may be used alone or in combination of two or more.

[0030] Examples of aromatic diamines include 2,2'-dimethyl-4,4'-diaminobiphenyl, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 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]sulfide, and 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, 4-amino-N-(4-aminophenyl)benzamide, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-trifluoromethyl-4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 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)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]propane-2-[4-(4-aminophenoxy)-3-methylphenyl]propane, 2,2-Bis[4-(4-aminophenoxy)phenyl]propane-2-Bis[4-(4-aminophenoxy)-3-methylphenyl]propane [nophenoxy)-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-aminophenoxy)benzoyl]benzene, 4,4'-bis[(3-aminophenoxy)benzoyl]benzene, 1,1-bis[4-(3-aminophenoxy)phenyl]propane, 1,3-bis[4-(3-aminophenoxy)phenyl]propane, 3,4'-diaminodiphenyl sulfide, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, bis[4-(3-aminophenoxy)phenyl]methane, 1,1-bis[4-(3-aminophenoxy)phenyl]ethane, 1,2-Bis[4-(3-aminophenoxy)phenyl]ethane, 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)pheno [Xy / 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-biphenoxybenzoyl)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]benzoyl Examples include tolyl, 4,4'-[9H-fluorene-9,9-diyl]bisaniline (also known as "9,9-bis(4-aminophenyl)fluorene"), spiro(xanthene-9,9'-fluorene)-2,6-diylbis(oxycarbonyl))bisaniline, 4,4'-[spiro(xanthene-9,9'-fluorene)-2,6-diylbis(oxycarbonyl))bisaniline, and 4,4'-[spiro(xanthene-9,9'-fluorene)-3,6-diylbis(oxycarbonyl))bisaniline. Furthermore, some or all of the hydrogen atoms on the aromatic ring of the above aromatic diamine may be substituted with halogen atoms, C1-C3 alkyl or alkoxyl groups, or cyano groups, and some or all of the hydrogen atoms of the C1-C3 alkyl or alkoxyl groups may be substituted with halogen atoms. Furthermore, there are no particular limitations on the aromatic diamines having the benzoxazole structure, and examples include 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), and 2,2'-p-phenylenebis. Nilenbis(6-aminobenzoxazole), 1-(5-aminobenzoxazolo)-4-(6-aminobenzoxazolo)benzene, 2,6-(4,4'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisxazole, 2,6-(4,4'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisxazole, 2,6-(3,4'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisxazole, 2,Examples include 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, and 2,6-(3,3'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole. Among these, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 4-amino-N-(4-aminophenyl)benzamide, 4,4'-diaminodiphenylsulfone, and 3,3'-diaminobenzophenone are particularly preferred. Aromatic diamines may be used individually or in combination.

[0031] Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propylcyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2-isobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, and 4,4'-methylenebis(2,6-dimethylcyclohexylamine). Among these, 1,4-diaminocyclohexane and 1,4-diamino-2-methylcyclohexane are particularly preferred, and 1,4-diaminocyclohexane is more preferred. The alicyclic diamines may be used individually or in combination.

[0032] Examples of diisocyanates include diphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate, and 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-diethyl Diphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-3,4'-diisocyanate, diphenyl ether-4,4' -Diisocyanate, benzophenone-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, torylene-2,4-diisocyanate, torylene-2,6-diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, naphthalene-2,6-diisocyanate, 4,4'-(2,2-bis(4-phenoxyphenyl)propane) diisocyanate, 3,3'-or 2,2'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'-or 2,2'-di Examples include aromatic diisocyanates such as ethyl biphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, and 3,3'-diethoxybiphenyl-4,4'-diisocyanate, as well as diisocyanates obtained by hydrogenating any of these (e.g., isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate).Among these, diphenylmethane-4,4'-diisocyanate, torylene-2,4-diisocyanate, torylene-2,6-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, naphthalene-2,6-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,4-cyclohexane diisocyanate are preferred in terms of low hygroscopicity, dimensional stability, cost, and polymerizability. Diisocyanates may be used individually or in combination.

[0033] <Polymer film layer> The polymer film layer of the present invention is a layer containing a polymer film, which is obtained by heating a polymer solution and volatilizing the solvent, or by heating a polymer precursor solution, volatilizing the solvent, and curing it. Examples of polymer solutions include soluble polyimide, and examples of polymer precursor solutions include polyamic acid solutions. The polymer film layer may be a single layer or a multi-layer (laminated) structure of two or more layers. In the case of a multi-layer polymer film layer, each polymer film layer may have the same composition or different compositions. When the polymer film layer has a single layer structure, the physical properties of the polymer film layer (melting point, glass transition temperature, yellowness index, total light transmittance, haze, CTE, etc.) refer to the values ​​for the entire polymer film layer. Even when the polymer film layer has a multi-layer structure, the physical properties of the polymer film layer refer to the values ​​for the entire polymer film layer.

[0034] The average coefficient of linear expansion (CTE) of the polymer film layer between 30°C and 250°C is preferably 50 ppm / K or less. More preferably 45 ppm / K or less, even more preferably 40 ppm / K or less, even more preferably 30 ppm / K or less, and particularly preferably 20 ppm / K or less. It is also preferably -5 ppm / K or more, more preferably -3 ppm / K or more, and even more preferably 1 ppm / K or more. When the CTE is within the above range, the difference in the coefficient of linear expansion with a general support (inorganic substrate) can be kept small, and peeling of the polymer film layer from the inorganic substrate or warping of the support can be avoided even when subjected to a heat-applying process. Here, CTE is a factor that represents reversible expansion and contraction with respect to temperature. The CTE of the polymer film layer refers to the average value of the CTE in the coating direction (MD direction) and the CTE in the width direction (TD direction) of the polymer solution or polymer precursor solution. The method for measuring the CTE of the polymer film layer is as described in the examples.

[0035] The polymer film layer is preferably a polyimide film, and may also be a transparent polyimide film. When the polymer film layer is a transparent polyimide film (hereinafter also referred to as the transparent polymer film layer), its yellowness index (hereinafter also referred to as "yellow index" or "YI") is preferably 10 or less, more preferably 7 or less, even more preferably 5 or less, and even more preferably 3 or less. The lower limit of the yellowness index of the transparent polyimide is not particularly limited, but for use as a flexible electronic device, it is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more.

[0036] The light transmittance of the transparent polymer film layer at a wavelength of 400 nm in the present invention is preferably 70% or more, more preferably 72% or more, even more preferably 75% or more, and even more preferably 80% or more. There is no particular upper limit to the light transmittance of the transparent polymer film layer at a wavelength of 400 nm, but for use as a flexible electronic device, it is preferably 99% or less, more preferably 98% or less, and even more preferably 97% or less.

[0037] The haze of the transparent polymer film layer in the present invention is preferably 1.0 or less, more preferably 0.8 or less, even more preferably 0.5 or less, and even more preferably 0.3 or less. The lower limit is not particularly limited, but industrially, a value of 0.01 or more is acceptable, and a value of 0.05 or more is also acceptable.

[0038] The polymer film 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. Furthermore, the glass transition temperature is preferably 200°C or higher, more preferably 320°C or higher, and even more preferably 380°C or higher. In this specification, the melting point and glass transition temperature are determined by differential thermal analysis (DSC). If the melting point exceeds 500°C, it may be determined whether the melting point has been reached by visually observing the thermal deformation behavior when heated at that temperature.

[0039] The thickness of the polymer film layer in the present invention is preferably 5 μm or more, more preferably 8 μm or more, even more preferably 15 μm or more, and even more preferably 20 μm or more. There is no particular upper limit to the thickness of the polymer film layer, but for use as a flexible electronic device, it is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 90 μm or less. If it is too thin, handling after device formation may be difficult, and if it is too thick, flexibility may be impaired.

[0040] The thickness variation of the polymer film layer is preferably 20% or less, more preferably 12% or less, even more preferably 7% or less, and particularly preferably 4% or less. If the thickness variation exceeds 20%, it tends to become difficult to apply to narrow areas. The thickness variation of the polymer film layer can be determined, for example, by peeling the polymer film layer from the inorganic substrate, artificially extracting about 10 points on the polymer film layer, measuring the thickness of the polymer film layer with a contact-type film thickness gauge, and determining it based on the following formula. Thickness variation (%) of thermoset polyamic acid products = 100 × (Maximum thickness - Minimum thickness) ÷ Average thickness

[0041] The polymer film layer may optionally contain a reaction catalyst (imidation catalyst), inorganic fine particles, etc. It is preferable to add the reaction catalyst, inorganic fine particles, etc., to the polymer solution or polymer precursor solution as needed.

[0042] As the imidation catalyst, it is preferable to use a tertiary amine. Heterocyclic tertiary amines are even more preferable. Preferred specific examples of heterocyclic tertiary amines include pyridine, 2,5-diethylpyridine, picoline, quinoline, and isoquinoline. The amount of imidizing agent used is preferably 0.01 to 2.00 equivalents, particularly 0.02 to 1.20 equivalents, relative to the reaction site of the polyamic acid (polyimide precursor). If the amount of imidation catalyst is less than 0.01 equivalents, the catalytic effect will not be sufficiently obtained, which is undesirable. If the amount is more than 2.00 equivalents, the proportion of catalyst that does not participate in the reaction increases, which is undesirable from a cost perspective.

[0043] Examples of inorganic fine particles include particulate silicon dioxide (silica) powder, inorganic oxide powders such as aluminum oxide powder, and inorganic salt powders such as particulate calcium carbonate powder and calcium phosphate powder. In the field of the present invention, coarse particles of these inorganic fine particles may cause defects in subsequent processes, so it is preferable that these inorganic fine particles be uniformly dispersed.

[0044] <Inorganic substrates> The inorganic substrate can be any plate-shaped substrate made of inorganic material, such as glass plates, ceramic plates, semiconductor wafers, metals, and composites of these materials, such as those laminated, dispersed, or containing fibers of these materials.

[0045] The aforementioned glass plates include quartz glass, high silica glass (96% silica), soda-lime glass, lead glass, aluminoborosilicate glass, borosilicate glass (Pyrex®), alkali-free borosilicate glass, borosilicate glass (microsheet), aluminosilicate glass, etc. Among these, those with a coefficient of thermal expansion of 5 ppm / K or less are desirable, and among commercially available products, Corning's "Corning® 7059," "Corning® 1737," and "EAGLE," which are liquid crystal glass, Asahi Glass's "AN100," Nippon Electric Glass's "OA10, OA11G," and SCHOTT's "AF32" are desirable.

[0046] The semiconductor wafers mentioned above are not particularly limited, but examples include silicon wafers, germanium, silicon-germanium, gallium-arsenide, aluminum-gallium-indium, nitrogen-phosphorus-arsenide-antimony, SiC, InP (indium phosphide), InGaAs, GaInNAs, LT, LN, ZnO (zinc oxide), CdTe (cadmium telluride), and ZnSe (zinc selenide). Among these, silicon wafers are preferred, and mirror-polished silicon wafers of 8 inches or larger are particularly preferred.

[0047] The aforementioned metals include single-element metals such as W, Mo, Pt, Fe, Ni, and Au, as well as alloys such as Inconel, Monel, Mnemonic, carbon-copper, Fe-Ni Invar alloy, and SuperInvar alloy. Multilayer metal sheets formed by adding other metal layers or ceramic layers to these metals are also included. In this case, if the overall coefficient of thermal expansion (CTE) with respect to the added layers is low, Cu and Al can also be used for the main metal layer. The metal used as the added metal layer is not limited to those that have properties such as strong adhesion to the thermoset polyamic acid, no diffusion, and good chemical and heat resistance, but Cr, Ni, TiN, and Mo-containing Cu are suitable examples.

[0048] The ceramic plates used in this invention include Al2O3, Mullite, ALN, SiC, crystallized glass, Cordierite, Spodumene, Pb-BSG+CaZrO3+Al2O3, and Crystallized glass+Al2O 3、 This includes substrate ceramics such as crystallized Ca-BSG, BSG+Quartz, BSG+Al2O3, Pb-BSG+Al2O3, glass-ceramic, and zero-dur materials.

[0049] The thickness of the inorganic substrate is not particularly limited, but from the viewpoint of handling, a thickness of 10 mm or less is preferred, more preferably 3 mm or less, and even more preferably 1.3 mm or less. 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, and even more preferably 0.3 mm or more. If it is too thin, it will be easily damaged and difficult to handle. If it is too thick, it will be heavy and difficult to handle.

[0050] Surface treatment may be performed to improve the wettability and adhesion of the inorganic substrate. Suitable surface treatment agents include silane coupling agents, aluminum-based coupling agents, and titanate-based coupling agents. Excellent properties can be obtained, in particular, when using silane coupling agents.

[0051] <Silane coupling agent (SCA)> In the laminate, it is preferable to have a silane coupling agent layer (also called a silane coupling agent condensation layer) between the polymer film layer and the inorganic substrate. In the present invention, the silane coupling agent refers to a compound containing 10% by mass or more of Si (silicon) component. By using a silane coupling agent layer, the intermediate layer between the thermoset polyamic acid layer and the inorganic substrate can be made thinner, resulting in fewer degassing components during heating, less elution even in wet processes, and even if elution occurs, it remains in trace amounts. The silane coupling agent is preferably one that contains a large amount of silicon dioxide component to improve heat resistance, and is particularly preferably one that has heat resistance at a temperature of about 400°C. The thickness of the silane coupling agent layer is preferably 200 nm or less (0.2 μm or less). For use as a flexible electronic device, it is preferably 100 nm or less (0.1 μm or less), more preferably 50 nm or less, and even more preferably 10 nm. When normally manufactured, it is about 0.10 μm or less. Furthermore, in processes where it is desirable to minimize the amount of silane coupling agent, it can be used even at 5 nm or less. Below 0.1 nm, the peel strength may decrease or there may be areas where adhesion is not achieved, so it is preferable to have a size of 0.1 nm or larger, and more preferably 0.5 nm or larger.

[0052] The silane coupling agent in this invention is not particularly limited, but those having an amino group or an epoxy group are preferred. If heat resistance is required in the process, it is desirable to have an aromatic group connecting Si and the amino group, etc.

[0053] The silane coupling agent is not particularly limited, but it is preferable to include a coupling agent having an amino group. Specific examples include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, aminophenyltrimethoxysilane, aminophenethyltrimethoxysilane, and aminophenylaminomethylphenethyltrimethoxysilane.

[0054] <Protective film> The first protective film and / or the second protective film are not particularly limited, and can include PET film, PEN film, polyethylene film, polypropylene film, nylon film, and other heat-resistant super engineering plastic films such as PPS film, PEEK film, aromatic polyamide film, polyimide film, and polyimide benzasol film. Among these, PET film is preferred. The first protective film and the second protective film may be the same or different. Industrially, it is preferable that the first protective film and the second protective film are both the same, and more preferably that both are PET films.

[0055] The protective film preferably has an adhesive layer on the surface in contact with the polymer film layer and / or the inorganic substrate. The presence of an adhesive layer in the protective film allows it to exhibit self-adhesion. The adhesive layer is not particularly limited, but for example, urethane-based, silicone-based, or acrylic-based adhesive layers can be used. The adhesive layer can be prepared by applying an adhesive dissolved in a solvent and drying it.

[0056] <Laminate> The first laminate of the present invention comprises an inorganic substrate, a polymer film layer, and a first protective film in that order, and the surface roughness Ra of the side of the inorganic substrate opposite to the polymer film layer is 0.02 μm to 1.2 μm. That is, the laminate has at least three layers: "inorganic substrate / polymer film layer / first protective film". The second laminate comprises a second protective film, an inorganic substrate, a polymer film layer, and a first protective film in that order, and the surface roughness Ra of the side of the second protective film opposite to the inorganic substrate is 0.02 μm to 1.2 μm. That is, the laminate has at least four layers: "second protective film / inorganic substrate / polymer film layer / first protective film". In addition, the silane coupling agent and other layers may be included between each layer. Furthermore, other layers may be laminated on the side of the first protective film opposite to the polymer film layer, and other layers may be laminated on the side of the second protective film opposite to the inorganic substrate. In this invention, the first laminate and the second laminate together are simply referred to as the laminate. Similarly, the first protective film and the second protective film together are simply referred to as the protective film.

[0057] <Method for manufacturing laminates> A laminate of an inorganic substrate and a polymer film layer can be manufactured by casting the aforementioned polymer solution or polymer precursor solution onto the inorganic substrate and heating it.

[0058] Known methods can be used for casting polymer solutions or polymer precursor solutions. For example, known casting methods such as gravure coating, spin coating, silkscreen coating, dip coating, bar coating, knife coating, roll coating, and die coating can be used.

[0059] When the polymer precursor solution is a polyamic acid solution, the polymerization solution described above may be used as is, but the solvent may be removed or added as needed. Suitable solvents for the polyamic acid solution include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone, as well as, for example, dimethyl sulfoxide, hexamethyl phosphoride, acetonitrile, acetone, and tetrahydrofuran. Additionally, xylene, toluene, benzene, diethylene glycol ethyl ether, diethylene glycol dimethyl ether, 1,2-bis-(2-methoxyethoxy)ethanebis(2-methoxyethyl) ether, butyl cellosolve, butyl cellosolve acetate, propylene glycol methyl ether, and propylene glycol methyl ether acetate may be used in combination as auxiliary solvents.

[0060] The polyamic acid of the present invention is preferably thermally imidized (thermally cured) at a temperature of 300°C to 450°C. That is, the polyimide of the present invention is preferably obtained by thermally imidizing (thermally curing) the polyamic acid at 300 to 450°C.

[0061] Thermal imidation is a method of carrying out the imidation reaction solely by heating, without the use of dehydrating ring-closing agents or the like. The heating temperature and time can be determined as appropriate, for example, as follows: First, to volatilize the solvent, heat at a temperature of 90 to 200°C for 3 to 120 minutes. The heating atmosphere can be air, under reduced pressure, or in an inert gas such as nitrogen. Known heating devices such as hot air ovens, infrared ovens, vacuum ovens, and hot plates can be used. Next, to further advance the imidation, heat at a temperature of 200 to 450°C for 3 to 240 minutes. It is preferable to gradually increase the heating conditions from a low temperature. The maximum temperature is preferably in the range of 300 to 450°C. If the maximum temperature is lower than 300°C, thermal imidation will not proceed easily, and the mechanical properties of the resulting polyimide film will deteriorate, which is undesirable. If the maximum temperature is higher than 450°C, thermal degradation of the polyimide will progress, and the properties will deteriorate, which is also undesirable. Furthermore, depending on the type and thickness of the polyamic acid, the type and surface condition of the inorganic substrate, and the heating conditions and methods during heating, the film may spontaneously peel off from the inorganic substrate during the heat treatment. Spontaneous peeling is undesirable because it makes it difficult to obtain a laminate with excellent properties. Generally, spontaneous peeling is more likely to occur as the film thickness increases, so it is preferable to adjust the aforementioned conditions for each thickness. In addition, to suppress spontaneous peeling, the casting of the polyamic acid solution and thermal imidization may be performed in multiple stages.

[0062] The solvent content in the polyimide is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less. Since a lower solvent content is preferable, there is no particular lower limit, but industrially, it is sufficient if it is 0.01% by mass or more, and 0.05% by mass or more is also acceptable.

[0063] In the present invention, the coating of polyamic acid solutions onto an inorganic substrate may be performed by sequentially or simultaneously applying multiple different polyamic acid solutions in a multi-layer coating. Specifically, these multiple different polyamic acid solutions refer to polyamic acid solutions with different compositions, polyamic acid solutions with different imidation rates, and polyamic acid solutions with different types and amounts of added inorganic particles or additives. Polyamic acid solutions other than the one in direct contact with the inorganic substrate may be polyimide solutions in which thermal imidation has been completed.

[0064] The coating of multiple polyamic acid solutions onto an inorganic substrate can be carried out using, for example, a two-layer die coater. By using a multi-layer die coater or by sequential coating, a laminate of an inorganic substrate and a polymer film layer (polyimide film) having a multi-layer structure of two or more layers can be obtained.

[0065] In the present invention, the coating of the polyamic acid solution onto an inorganic substrate may be performed by first coating the inorganic substrate with the first layer, then heating it at a temperature of 100 to 200°C for 3 to 120 minutes to evaporate the solvent, and finally coating it with the second layer of polyamic acid solution.

[0066] In the present invention, the laminate of an inorganic substrate and a polyimide film may be obtained by coating the inorganic substrate with a polyamic acid solution, then bonding the polyimide film to it before heating, and finally heating the substrate.

[0067] In order to obtain the laminate of an inorganic substrate and a polyimide film according to the present invention, a polyamic acid solution that has been pre-coated in a single or multiple layer on another support is heated to form a self-supporting film, which is then bonded to the inorganic substrate and heated.

[0068] The laminate of an inorganic substrate and a polyimide film in the present invention can also be obtained by laminating a thermoset polyamic acid, which has been pre-formed into a single-layer or multi-layer film, to an inorganic substrate. A single-layer or multi-layer polyimide film can be obtained by coating a polyamic acid solution onto a support such as a metal belt or a resin film, drying it to form a self-supporting film, and then performing thermal imidation. The coating of the polyamic acid solution onto the support may be simultaneous multi-layer coating, or the first layer may be coated and dried, and then the polyamic acid solution may be coated, dried, and imidized on top of it. Similarly, when laminating three or more layers of polyamic acid solution, a multi-layer film can be obtained by repeating coating and heating simultaneously or sequentially.

[0069] The laminate of the present invention can also be manufactured, for example, by the following procedure. A laminate can be obtained by pre-treating at least one surface of an inorganic substrate with a silane coupling agent, overlapping the silane coupling agent-treated surface with a film-like polyimide, and laminating the two by pressurizing. Alternatively, a laminate can be obtained by pre-treating at least one surface of a film-like polyimide with a silane coupling agent, overlapping the silane coupling agent-treated surface with an inorganic substrate, and laminating the two by pressurizing. As for the pressurizing method, there are conventional pressing or lamination in air or pressing or lamination in a vacuum, but in order to obtain stable peel strength across the entire surface, lamination in air is desirable for large-sized laminates (e.g., over 200 mm). In contrast, for small-sized laminates of about 200 mm or less, pressing in a vacuum is preferable. The vacuum level can be sufficiently achieved with a normal oil rotary pump, and a vacuum of about 10 Torr or less is sufficient. The preferred pressure is 1 MPa to 20 MPa, and more preferably 3 MPa to 10 MPa. High pressure may damage the substrate, while low pressure may result in areas that do not adhere properly. The preferred temperature range is 90°C to 300°C, more preferably 100°C to 250°C. High temperatures can damage the polyimide, while low temperatures may result in weak adhesion.

[0070] The shape of the laminate is not particularly limited and may be square or rectangular. Preferably, it is rectangular, with the length of the longest side being 300 mm or more, more preferably 500 mm or more, and even more preferably 1000 mm or more. There is no particular upper limit, but industrially, 20,000 mm or less is sufficient, and 10,000 mm or less is also acceptable. Furthermore, it is preferable that the diameter of the circumscribed circle of the inorganic substrate is 310 mm or more. Since the laminate of the present invention can be packaged in a stacked form for storage and transportation even when it is large, it is more preferably 350 mm or more, and even more preferably 400 mm or more. Furthermore, industrially, 30,000 mm or less is sufficient, and 20,000 mm or less is also acceptable.

[0071] <Adhesive> In this invention, it is preferable that there is substantially no adhesive layer between the inorganic substrate and the polymer film layer. Here, the adhesive layer referred to in this invention refers to one in which the Si (silicon) component is less than 10% by mass (less than 10% by mass). Furthermore, "substantially not used (not interposed)" means that the thickness of the adhesive layer interposed between the inorganic substrate and the polymer film layer is preferably 0.4 μm or less, more preferably 0.3 μm or less, even more preferably 0.2 μm or less, particularly preferably 0.1 μm or less, and most preferably 0 μm.

[0072] In the present invention, after a laminate of an inorganic substrate and a polymer film layer is fabricated, a first protective film is bonded to the surface of the polymer film layer. The first protective film may be separated and independent for each inorganic substrate / polymer film layer laminate, or it may be continuous so that the laminate forms a continuous sheet.

[0073] In the present invention, after a laminate of an inorganic substrate and a polymer film layer is fabricated, a second protective film may be bonded to the side of the inorganic substrate opposite to the polymer film layer. The second protective film may be separated and independent for each inorganic substrate / polymer film layer laminate, or it may be continuous so that the laminate forms a continuous sheet.

[0074] In other words, when the first protective film and the second protective film are used simultaneously in the present invention, the following three patterns are possible. (1) Both the first protective film and the second protective film are separated into individual inorganic substrate / polymer film layers. (2) The first protective film forms a continuous sheet of inorganic substrate / polymer film layers, and the second protective film is separated for each layer of inorganic substrate / polymer film layers. (3) The second protective film forms a continuous sheet of inorganic substrate / polymer film layers, and the first protective film is separated for each layer of inorganic substrate / polymer film layers.

[0075] In this context, "continuous sheet" refers to a state in which two or more laminates of inorganic substrate / polymer film layers are connected by a continuous protective film.

[0076] The bonding of the first protective film and the second protective film to the inorganic substrate / polymer film layer may be simultaneous, as shown in Figure 1(b), or sequentially. There are no particular restrictions on the bonding order, but from the viewpoint of protecting the surface of the polymer film layer, it is preferable that the first protective film is bonded first.

[0077] When a pre-cured thermoset polyamic acid (specifically, a polyimide film, etc.) is used as the polymer film layer in the laminate, the first protective film and / or the second protective film may be pre-bonded to the thermoset polyamic acid. In this case, the laminate can be made using pre-cut single-sheet films, or a long roll of film can be unwound and bonded to an inorganic substrate, and the film can be cut before and after bonding to create a single-sheet laminate. Even once a laminate has been formed into single sheets, it can be made into a continuous sheet by bonding the first and / or the second protective film.

[0078] The surface roughness Ra of the second protective film substrate on the side opposite to the inorganic substrate in the second laminate of the present invention is preferably 0.02 μm or more, more preferably 0.025 μm or more, and even more preferably 0.03 μm or more. The upper limit is preferably 1.2 μm or less, more preferably 0.6 μm or less, and even more preferably in the range of 0.3 μm or less. As a method for controlling the surface roughness of a protective film substrate to a predetermined range, one example is to add inorganic particles to the raw resin during the film manufacturing process of the protective film substrate to control the surface roughness. As inorganic particles, known inorganic particles such as silica, alumina, calcia, magnesia, calcium carbonate, magnesium carbonate, calcium phosphate, magnesium phosphate, barium sulfate, talc, and kaolin can be added in predetermined amounts. The amount added is not uniform depending on the stretching ratio during substrate film production, the final substrate film thickness, and the particle size distribution of the added inorganic particles, but generally it is 500 ppm or more, preferably 1000 ppm or more, and more preferably 2000 ppm or more, in mass ratio to the mass of the substrate film resin, with an upper limit of 10% by mass or less, preferably 3% by mass or less, and more preferably 10000 ppm or less. As a method for controlling the surface roughness of a protective film substrate to a predetermined range, one example is to polish or grind the surface of the film substrate to achieve the predetermined surface roughness. Furthermore, as a method for controlling the surface roughness of the protective film substrate to a predetermined range, one example is to cast the film material onto a support substrate that has been manufactured in advance to have a predetermined surface roughness in order to obtain the protective film substrate. Another example is to control the surface roughness of the protective film substrate by pressing an embossing roller or the like, which has been processed to have a predetermined surface shape, against it.

[0079] In the laminate of the present invention, the surface roughness of the side of the first protective film opposite to the polymer film layer is preferably 0.005 μm or more. More preferably 0.01 μm or more. When the surface roughness of the side of the first protective film opposite to the polymer film layer is 0.005 μm or more, even when multiple laminates are stacked and stored for a long period of time, they can be easily removed individually, provided that the surface roughness of the side of the inorganic substrate opposite to the polymer film layer or the side of the second protective film opposite to the inorganic substrate is within a predetermined range. There is no particular upper limit for the surface roughness, but since it is preferable that the first protective film and the second protective film are made of the same material, it is preferably 1.2 μm or less, and more preferably 1 μm or less.

[0080] In the first laminate of the present invention, the surface roughness Ra of the inorganic substrate on the side opposite to the polymer film layer is 0.02 μm to 1.2 μm. Even when multiple laminates are stacked and stored for a long period of time, they do not stick to the protective film surface and can be easily removed individually, resulting in good handling. Therefore, it is preferably 0.025 μm or more, more preferably 0.03 μm or more, and even more preferably 0.05 μm or more. It is also preferably 1.15 μm or less, and more preferably 1.1 μm or less. Polishing methods such as shot blasting and wet blasting can be used to control the surface roughness of the inorganic substrate within a predetermined range.

[0081] In the first laminate of the present invention, the coefficient of dynamic friction between the surface of the first protective film opposite to the polymer film layer and the surface of the inorganic substrate opposite to the polymer film layer is preferably in the range of 0.02 to 0.25. Even when multiple first laminates are stacked and stored for a long period of time, they can be easily removed individually without sticking to the protective film surface, resulting in even better handling. Therefore, it is preferably 0.05 to 0.24, and more preferably 0.10 to 0.23. The coefficient of dynamic friction can be achieved by controlling the surface roughness of the surface of the first protective film opposite to the polymer film layer and the surface of the inorganic substrate opposite to the polymer film layer to the above range.

[0082] In the second laminate of the present invention, it is preferable that the coefficient of dynamic friction between the surface of the first protective film opposite to the polymer film layer and the surface of the second protective film opposite to the inorganic substrate is in the range of 0.02 to 0.25. Even when multiple laminates are packed in a stacked state and stored for a long period of time, they can be easily removed individually without sticking to the protective film surface, resulting in even better handling. Therefore, it is preferable that the coefficient of dynamic friction is 0.05 to 0.24, and more preferably 0.10 to 0.23. The coefficient of dynamic friction can be achieved by controlling the surface roughness of the surface of the first protective film opposite to the polymer film layer and the surface of the second protective film opposite to the inorganic substrate to the aforementioned range.

[0083] In the second laminate of the present invention, it is preferable that the coefficient of dynamic friction between the surfaces of the second protective film opposite to the inorganic substrate is in the range of 0.02 to 0.25. Even when multiple laminates are packaged in a stacked state and stored for a long period of time, they can be easily removed individually without sticking to the protective film surface, resulting in even better handling. Therefore, it is preferably 0.05 to 0.24, and more preferably 0.10 to 0.23. The coefficient of dynamic friction can be achieved by controlling the surface roughness of the surface of the second protective film opposite to the inorganic substrate within the aforementioned range.

[0084] In the present invention, multiple laminates described above, preferably four or more, and more preferably ten or more, can be stacked together to form a stack. When stacking, the orientation of the laminates may be the same or different, but it is preferable that they be the same orientation. In the present invention, since the coefficient of dynamic friction between the contacting surfaces when stacked is within a predetermined range, it is possible to easily remove individual laminates from the stack. Furthermore, the laminates used for stacking may be of the same type only, or different types of laminates may be used randomly. Preferably, the stack is made using only laminates of the same type, and preferred embodiments include stacking multiple first laminates and stacking multiple second laminates.

[0085] In this invention, the laminate can be stored in the stacked state obtained in this way. When storing, it is preferable to package the laminate in the stacked state. The stack of this invention can be stored in any of the following ways: with the inorganic substrate of the stack in the horizontal direction, with the inorganic substrate of the stack in the vertical direction, or tilted to approximately 75 to 89 degrees close to vertical.

[0086] In this invention, the laminate can be transported in the stacked state obtained in this way. When transporting, it is preferable to pack the laminate in the stacked state. The stack of this invention can be transported in any of the following ways: when the inorganic substrate of the stack is held horizontally, when the stack is held vertically, or when it is tilted to about 75 to 89 degrees, close to vertical. [Examples]

[0087] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. The method for evaluating the physical properties in the following examples is as follows.

[0088] <Surface roughness> Surface roughness Ra was measured using a stylus-type surface roughness meter in accordance with ISO 25178-2:2012.

[0089] <Coefficient of Dynamic Friction> The coefficient of dynamic friction was measured in accordance with JIS K 7125:1999 by attaching a friction coefficient jig to a tensile testing machine. Tensile testing machine: Shimadzu Corporation "Autograph® AG-IS"

[0090] <Preparation of Polyimide Solution A1> In a reaction vessel equipped with a nitrogen inlet tube, a Dean-Stark tube and reflux tube, a thermometer, and a stirring rod, 19.86 parts by mass of 4,4'-diaminodiphenyl sulfone (4,4'-DDS), 4.97 parts by mass of 3,3'-diaminodiphenyl sulfone (3,3'-DDS), and 80 parts by mass of γ-butyrolactone (GBL) were added while introducing nitrogen gas. Subsequently, 31.02 parts by mass of 4,4'-oxydiphthalic acid unhydrate (ODPA), 24 parts by mass of GBL, and 13 parts by mass of toluene were added at room temperature. The internal temperature was then raised to 160°C, and the mixture was heated under reflux at 160°C for 1 hour to carry out imidation. After imidation was complete, the temperature was raised to 180°C, and the reaction was continued while removing toluene. After 12 hours of reaction, the oil bath was removed and the mixture returned to room temperature. GBL was added to a solid content of 20% by mass to obtain polyimide solution A1 with a reduced viscosity of 0.70 dl / g.

[0091] <Preparation of polyamic acid solution B1> After purging the reaction vessel, equipped with a nitrogen inlet tube, reflux tube, and stirring rod, with nitrogen, 33.36 parts by mass of 2,2'-bis(trifluoromethyl)benzidine (TFMB) was completely dissolved in 270.37 parts by mass of dimethylacetamide (DMAc). Then, 9.81 parts by mass of 1,2,3,4-cyclobutanetetracarboxylic acid nonhydrate (CBDA), 11.34 parts by mass of 3,3',4,4'-biphenyltetracarboxylic acid, and 4.85 parts by mass of (ODPA) were added in solid form in divided portions, and the mixture was stirred at room temperature for 24 hours. Subsequently, 165.7 parts by mass of DMAc was added to dilute the mixture and obtain a polyamic acid solution B1 (CBDA / BPDA / ODPA / TFMB = 0.48 / 0.37 / 0.15 / 1.00 (molar ratio)) with a solid content of 18% by mass and a reduced viscosity of 2.7 dl / g.

[0092] <Preparation of polyamic acid solution B2> After purging the reaction vessel, equipped with a nitrogen inlet tube, reflux tube, and stirring rod, with nitrogen, 22.73 parts by mass of 4,4'-diaminobenzanilide (DABAN), 201.1 parts by mass of N,N-dimethylacetamide (DMAc), and a dispersion (Nissan Chemical Industries' "Snowtex® DMAC-ST-ZL") prepared by dispersing colloidal silica (lubricant) in dimethylacetamide were added so that the colloidal silica (lubricant) amounted to 0.4% by mass of the total polymer solids in the polyamic acid solution, and the mixture was completely dissolved. Next, 22.73 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added in solid form in portions, and the mixture was stirred at room temperature for 24 hours. Subsequently, 173.1 parts by mass of DMAc were added to dilute the mixture, yielding polyamic acid solution B2 with a solid content (NV) of 12% by mass and a reduced viscosity (ηsp / C) of 3.10 dl / g.

[0093] <Preparation of protective film substrate> The following materials were used as the protective film substrate. PET film, 25 μm thick, made from Toyobo Co., Ltd.'s E5100 with a single-sided sandblasted matte finish. Toray Industries, Inc.'s Trefan®, single-sided corona treated, polypropylene film, 26 μm thick. CosmoShine® PET film, manufactured by Toyobo Co., Ltd., 100 μm thick.

[0094] <Preparation of the adhesive layer and fabrication of the protective film> 100 parts by mass of urethane-based solvent-type adhesive US-902-50 (manufactured by Lion Specialty Chemicals, ethyl acetate solvent, 50% solids content) was stirred and 5.4 parts by mass of crosslinking agent (manufactured by Lion Specialty Chemicals) and 2 parts by mass of ultraviolet absorber (Cyasorb UV-3638 (manufactured by CYTEC)) were added, and the mixture was reacted at 40°C for 20 minutes. The resulting solution was filtered through a PTFE cartridge filter (0.45 μm), and then coated onto a protective film substrate to a final film thickness of 10 μm. A protective film was obtained by heating at 100°C for 2 minutes. For PF1, E5100 (adhesive coating on a non-sand matte treated surface) was used as the substrate, for PF2, Trefan was used, and for PF3, Cosmoshine was used.

[0095] <Fabrication of laminate L1> Polyimide solution A1 was cast onto a rectangular alkali-free glass S1 (NEG OA11G, uncoated surface, wet-blasted) measuring 500 mm x 400 mm (circumscribed diameter 640.3 mm) and 0.7 mm thick, using a bar coater to achieve a dry thickness of 15 μm. It was then dried in a hot air oven at 110°C for 1 hour. The resulting laminate of glass and dried polyimide solution was further heated gradually at 5°C / min to 330°C, and then heated for another 10 minutes to evaporate the solvent, thereby obtaining a laminate of a polyimide film and an alkali-free glass plate with a thickness of approximately 15 μm. A protective film PF1 (adhesive coated surface) was bonded to the surface of the polyimide film to obtain a laminate L1 of the polyimide film with the first protective film and the alkali-free glass plate.

[0096] <Fabrication of laminate L2> Polyamic acid solution B1 was cast onto a rectangular 500mm x 400mm, 0.7mm thick alkali-free glass (NEG OA11G, uncoated surface, wet-blasted) using a bar coater to a dry thickness of 15μm, and dried in a hot air oven at 100°C for 1 hour. The resulting laminate of glass and dried polyamic acid solution was then gradually heated to 350°C at a rate of 5°C / min, and further heated for 10 minutes to imidize it, thereby obtaining a laminate of a polyimide film with a thickness of approximately 15μm and an alkali-free glass plate. A protective film PF1 (adhesive coated surface) was bonded to the surface of the polyimide film to obtain a laminate L2 of the polyimide film with the first protective film and an alkali-free glass plate.

[0097] <Fabrication of laminate L3> A silane coupling agent was applied to a glass plate, a polyimide film was laminated to it, and then heated to obtain a laminate of glass and polyimide. First, the method for applying the silane coupling agent to the glass substrate was carried out using the apparatus shown in Figure 5. Figure 5 is a schematic diagram of the apparatus for applying the silane coupling agent to the glass substrate. The glass substrate used was 0.7 mm thick OA11G glass (manufactured by NEG Corporation) cut to a size of 500 mm x 400 mm, with the side not coated with the silane coupling agent wet-blasted. The glass substrate was also used after being washed with pure water in an ultrasonic cleaner for 2 minutes, and then the moisture was removed with an air knife. 150 g of 3-aminopropyltrimethoxysilane (silane coupling agent Shin-Etsu Chemical KBM903) was placed in a 1 L chemical tank, and the water bath outside was heated to 43°C. The resulting steam was then sent into the chamber along with clean dry air. The gas flow rate was 25 L / min, and the substrate temperature was 24°C. The clean dry air temperature was 23°C and the humidity was 1.2%RH. Since the exhaust was connected to a negative pressure exhaust port, a differential pressure gauge confirmed that the chamber was under a negative pressure of approximately 2 Pa.

[0098] Next, a polymer film layer, UBE Industries Ltd.'s UPIREX® 25S (450mm x 450mm size), was laminated onto the silane coupling agent layer to obtain a laminate. An MCK Corporation laminator MRK650Y was used for lamination, with the following lamination conditions: compressed air pressure: 0.6 MPa, temperature: 22°C, humidity: 55% RH, and lamination speed: 50 mm / sec. This polyimide film / glass laminate was heated at 200°C for 30 mins to obtain a laminate of polyimide film and alkali-free glass plate. A protective film PF1 (adhesive coated surface) was laminated to the surface of the polyimide film to obtain a laminate L3 of polyimide film with the first protective film and alkali-free glass plate.

[0099] <Fabrication of laminate L4> A laminate of polyimide film with a first protective film and glass was obtained in the same manner as laminate L3, except that Xenomax (registered trademark) F15LR2 manufactured by Toyobo Co., Ltd. was used as the polyimide film. Protective film PF1 was bonded to the glass opposite the polyimide film to obtain laminate L4 of polyimide film with first and second protective films and alkali-free glass plate.

[0100] <Fabrication of laminate L5> Polyamic acid solution B2 was cast onto a rectangular alkali-free glass S2 (NEG OA11G) measuring 500 mm x 400 mm and 0.7 mm thick using a bar coater to a dry thickness of 15 μm, and dried in a hot air oven at 100°C for 1 hour. The resulting laminate of glass and dried polyamic acid solution was then gradually heated to 350°C at a rate of 5°C / min, and further heated for 10 minutes to imidize it, thereby obtaining a laminate of a polyimide film with a thickness of approximately 15 μm and an alkali-free glass plate. Protective film PF1 (adhesive coated side) was laminated to the surface of the polyimide film to obtain a laminate of polyimide film with the first protective film and an alkali-free glass plate. Protective film PF1 (adhesive coated side) was laminated to the side of the glass opposite the polyimide film to obtain a laminate L5 of polyimide film with the first and second protective films and an alkali-free glass plate.

[0101] <Fabrication of laminate L6> Polyimide solution A1 was cast onto a rectangular 500mm x 400mm, 0.7mm thick alkali-free glass (NEG OA11G) using a bar coater to a dry thickness of 15μm, and dried in a hot air oven at 110°C for 1 hour. The resulting laminate of glass and the dried polyamic acid solution was then gradually heated to 300°C at a rate of 5°C / min, and heated for another 10 minutes to evaporate the solvent, thereby obtaining a laminate of a polyimide film with a thickness of approximately 15μm and an alkali-free glass plate. Protective film PF1 (adhesive coated side) was laminated to the surface of the polyimide film to obtain a laminate of the polyimide film with the first protective film and an alkali-free glass plate. Protective film PF2 was laminated to the side of the glass opposite the polyimide film to obtain a laminate L6 of the thermoset polyimide film with the first and second protective films and an alkali-free glass plate.

[0102] <Fabrication of laminate L7> A laminate L7 consisting of a polyimide film with a first protective film and an alkali-free glass plate was obtained in the same manner as laminate L4, except that wet blasting treatment was not performed on the glass and a second protective film was not used.

[0103] <Fabrication of laminate L8> A laminate L8 consisting of a polyimide film with a first protective film and an alkali-free glass plate was obtained in the same manner as laminate L1, except that wet blasting treatment was not performed on the glass.

[0104] <Fabrication of laminate L9> A laminate L9 consisting of a polyimide film with first and second protective films and an alkali-free glass plate was obtained in the same manner as laminate L3, except that wet blasting treatment was not performed on the glass and PF3 was used as the second protective film.

[0105] <Evaluation of handling characteristics of laminated stacks> Ten stacks of laminates were arranged horizontally on a flat tabletop with the glass plates facing downwards to form a stack of laminates. On top of these stacks were another glass plate of the same size, a 50 μm thick polyethylene film, and a 3 mm thick silicone rubber sheet of the same size as the glass plate. A 10 mm thick stainless steel plate was then placed on top as a weight, and the stacks were left undisturbed at room temperature for 10 days. After 10 days, the weights, silicone rubber sheets, and polyethylene film were removed, and it was checked whether each laminate could be manually removed from the stack of 10 laminates. If the laminate could be removed without any problems, it was marked as "good handling" (○), and if any problems occurred during removal, it was marked as "poor handling" (×). The results are shown in Table 1. In the case of poor handling, the protective film on the back of the glass plate would adhere tightly to the back of the glass plate, causing the protective film on the lower layer to peel off when the glass plate was lifted.

[0106] [Table 1]

[0107] <Evaluation of transport suitability of laminated stacks> In the handling performance evaluation described above, 10 sets of laminated material combinations deemed to have good handling performance were stacked together to form laminated stacks. The laminated stacks were wrapped in kraft paper, placed in a corrugated plastic case along with a 20mm thick polyurethane cushion, loaded onto the bed of a small truck, and transported 30km on a public highway. Upon arrival, the packaging was removed, and the handling performance was re-evaluated using the method described above. In all combinations, the laminates could be removed without any particular problems. Furthermore, no accidents such as glass breakage occurred during transport. [Industrial applicability]

[0108] As described above, the laminate of the inorganic substrate and polymer film layer of the present invention offers excellent handling and transportability, can be handled with the polymer film surface protected by a protective film, and the protective film can be peeled off without any problems when processing is performed on the polymer film surface. The present invention can be usefully used in the manufacture of flexible devices and the like by microfabricating a polymer film using such a laminate and then peeling the polymer film from an inorganic substrate. [Explanation of Symbols]

[0109] 11. Polyamic acid solution 12, 21, 32, 41 Inorganic substrates 13 Laminating Rollers 14, 23, 33, 43 First protective film 15, 22, 31, 42 Polymer film layer 16, 34, 44 Second protective film 51 Flow meter 52 Gas inlet 53. Chemical solution tank (silane coupling agent tank) 54. Hot water bath (water bath) 55 Heater 56 Processing Chamber 57 Base material 58 Exhaust vent

Claims

1. The material comprises an inorganic substrate, a polymer film layer, and a first protective film in this order, wherein the surface roughness Ra of the inorganic substrate on the side opposite to the polymer film layer is 0.02 μm to 1.2 μm. The polymer film layer is a polyimide film, The first laminate is characterized in that the laminate of the inorganic substrate / polymer film layer is formed into a continuous sheet by the first protective film.

2. The first laminate according to claim 1, characterized in that the coefficient of dynamic friction between the surface of the first protective film opposite to the polymer film layer and the surface of the inorganic substrate opposite to the polymer film layer is in the range of 0.02 to 0.

25.

3. The second protective film, an inorganic substrate, a polymer film layer, and a first protective film are included in this order, and the surface roughness Ra of the side of the second protective film opposite to the inorganic substrate is 0.02 μm to 1.2 μm. The polymer film layer is a polyimide film, The first protective film forms the laminate of the inorganic substrate / polymer film layer into a continuous sheet, and the second protective film is separated for each laminate of the inorganic substrate / polymer film layer, or The second protective film forms the laminate of the inorganic substrate / polymer film layer into a continuous sheet, and the first protective film is separated for each laminate of the inorganic substrate / polymer film layer. A second laminate characterized by the above.

4. The second laminate according to claim 3, characterized in that the coefficient of dynamic friction between the surface of the first protective film opposite to the polymer film layer and the surface of the second protective film opposite to the inorganic substrate is in the range of 0.02 to 0.

25.

5. The second laminate according to claim 3 or 4, characterized in that the coefficient of dynamic friction between the surfaces of the second protective film opposite to the inorganic substrate is in the range of 0.02 to 0.

25.

6. The laminate according to any one of claims 1 to 5, characterized in that the diameter of the circumscribed circle of the inorganic substrate is 310 mm or more.

7. A laminate stack characterized by stacking four or more laminates according to any one of claims 1 to 6 in the same orientation in the layer direction.

8. A method for storing a laminate, characterized by storing it in the form of a laminate stack described in claim 7.

9. A method for transporting a laminate, characterized by transporting it in the form of a laminate stack as described in claim 7.

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