Laminate

Abstract

Provided is a laminate having a protective film release auxiliary tape and comprising a rigid temporary support body (inorganic substrate) and a polymer film provided with a protective film. The laminate is configured such that the protective film can be peeled off from the polymer film without separating the polymer film from the temporary support body (inorganic substrate).　This laminate is characterized: by comprising an inorganic substrate, a heat-resistant polymer film, a protective film, and a protective film release auxiliary tape in this order; and in that the adhesion strength F1 according to a 90 degree peeling method between the inorganic substrate and the heat-resistant polymer film, the adhesion strength F2 according to a 90 degree peeling method between the heat-resistant polymer film and the protective film, and the adhesion strength F3 according to a 90 degree peeling method between the protective film and the protective film release auxiliary tape satisfy the relationship F3>F1>F2.

Description

Laminate

[0001] The present invention relates to a laminate of an inorganic substrate, a polymer film layer with a protective film, and a protective film peeling aid tape.

[0002] The use of heat-resistant polymer films (hereinafter simply referred to as "polymer films") such as polyimide as substrate materials for manufacturing flexible electronic devices is being considered. Because such polymer films such as polyimide are manufactured in long rolls, a roll-to-roll production line is generally considered ideal for manufacturing flexible devices.

[0003] On the other hand, many conventional electronic devices, such as display devices, sensor arrays, touch screens, and printed wiring boards, use hard rigid substrates such as glass substrates, semiconductor wafers, or glass fiber reinforced epoxy substrates, and manufacturing equipment is also designed to use such rigid substrates.

[0004] Given this background, a known method for manufacturing flexible electronic devices using existing manufacturing equipment involves using a rigid inorganic substrate such as a glass substrate as a temporary support, handling the temporary support while a polymer film is temporarily attached to it, processing the polymer film into an electronic device, and then peeling the polymer film with the electronic device formed thereon from the temporary support (Patent Document 1). Another known method for manufacturing flexible electronic devices using existing manufacturing equipment involves using a rigid substrate such as a glass substrate as a temporary support, applying a polymer solution or polymer precursor solution to the temporary support, drying the solution to form a precursor film, and then chemically converting the precursor into a polymer film, thereby obtaining a laminate of the temporary support and the polymer film. Subsequently, an electronic device is formed on the polymer film in the same manner, followed by peeling the film off to produce a flexible electronic device (Patent Document 2). Incidentally, in the process of forming a desired functional element on a laminate formed by bonding a polymer film to an inorganic support, the laminate is often exposed to high temperatures. For example, forming functional elements such as polysilicon or oxide semiconductors requires a process at a temperature range of approximately 200°C to 600°C. Furthermore, in the production of hydrogenated amorphous silicon thin films, the film may be subjected to temperatures of around 200 to 300° C., and further heating and dehydrogenating the amorphous silicon to produce low-temperature polysilicon may require heating to around 450 to 600° C. Therefore, the polymer films that make up the laminate are required to be heat resistant, but in reality, there are only a limited number of polymer films that can withstand such high temperatures, and polyimide is often the material of choice.

[0005] That is, in either method, a laminate is produced in the form of a rigid temporary support and a polymer film layer that will eventually be peeled off to become the base material of a flexible electronic device. Because such a laminate can be handled as a rigid plate material, it can be handled in the same way as a glass substrate in equipment used to manufacture liquid crystal displays, plasma displays, organic EL displays, etc. that use conventional glass substrates.

[0006] Patent No. 5152104 Patent No. 5699606

[0007] Conventional rigid inorganic substrates, such as glass substrates, are handled in the form of a stack of multiple substrates during storage or transportation. When stacked, buffer materials such as foamed polymer sheets or paper are sandwiched between the inorganic substrates to facilitate removal of the inorganic substrates from the stack after storage or transportation. While this method is applicable to glass substrates with sufficient surface hardness, the polymer film surface of the laminate of the inorganic substrate (temporary support substrate) and polymer film used in the present invention lacks sufficient hardness. Therefore, when the laminate is stacked, the polymer film surface of the laminate rubs against the inorganic substrate surface, resulting in scratches on the soft polymer film surface. Furthermore, even when buffer materials such as foamed polymer sheets or paper are inserted, the polymer film surface is prone to scratches due to contaminants or other foreign matter.

[0008] A commonly used method for solving such problems is to protect the polymer film surface with a protective film. Generally, the protective film is a low-adhesion film in which a weak adhesive material is applied to one side of a relatively inexpensive polymer film such as polyethylene, polypropylene, or polyester. Furthermore, from the viewpoint of cost reduction, a self-adhesive resin film such as a polyolefin resin may also be used.

[0009] By using such a protective film, the surface of the polymer film is prevented from being scratched, and it becomes possible to maintain the surface of the polymer film in a state suitable for forming fine flexible electronic devices.

[0010] However, the present inventors have encountered the problem that when peeling the protective film from a laminate of a polymer film and an inorganic substrate with the protective film attached, it is difficult to peel the protective film from the polymer film without peeling the inorganic substrate from the polymer film. The laminate of the inorganic substrate and polymer film of the present invention is laminated with weak adhesive strength so that it can be peeled off after finally fabricating a device on the polymer film surface. Therefore, if the peel strength between the polymer film and the protective film is equal to or greater than the peel strength between the inorganic substrate and the polymer film, it is difficult to peel off only the protective film.

[0011] The problem to be solved by the present invention is to provide a laminate with a protective film peeling auxiliary tape that can peel the protective film and polymer film from a laminate including a polymer film with a protective film and a rigid temporary support (inorganic substrate) without peeling the polymer film and temporary support (inorganic substrate).

[0012] That is, the present invention includes the following configurations. [1] A laminate comprising, in this order, an inorganic substrate, a heat-resistant polymer film, a protective film, and a protective film peeling aid tape, wherein the adhesive strength F1 between the inorganic substrate and the heat-resistant polymer film as measured by a 90-degree peeling method, the adhesive strength F2 between the heat-resistant polymer film and the protective film as measured by a 90-degree peeling method, and the adhesive strength F3 between the protective film and the protective film peeling aid tape as measured by a 90-degree peeling method satisfy the relationship F3 > F1 > F2 (1). [2] The laminate according to [1], wherein the protective film has a 50% UV cutoff wavelength of 240 nm or more. [3] The laminate according to [1] or [2], wherein the change in F2 of the laminate before and after heating at 120°C for 10 minutes is 50% or less. [4] The laminate according to any one of [1] to [3], wherein the area B1 of the protective film and the area B2 of the protective film peeling aid tape satisfy the relationship B1 > B2. [5] The laminate according to any one of [1] to [4], wherein the arithmetic mean waviness Wa of the surface of the protective film in contact with the heat-resistant polymer film is 30 nm or less. [6] The laminate according to any one of [1] to [5], wherein the heat-resistant polymer film contains at least one selected from the group consisting of polyimide, polyamide, and polyamideimide. [7] The laminate according to any one of [1] to [5], wherein the heat-resistant polymer film is a transparent polyimide.

[0013] In a laminate including a polymer film with a protective film and a rigid temporary support (inorganic substrate), by making the adhesive strength F1 between the inorganic substrate and the polymer film greater than the adhesive strength F2 between the polymer film and the protective film, and by further increasing the adhesive strength F3 between the protective film and the protective film peeling auxiliary tape, it is possible to easily peel off only the protective film without peeling off the inorganic substrate and the polymer film, regardless of whether manual peeling or mechanical peeling is performed.

[0014] 1(a) to 1(e) are schematic diagrams of a laminate (inorganic substrate / heat-resistant polymer film / protective film / protective film peeling aid tape) of the present invention. 2(a), 2(b), and 2(c) are schematic diagrams of cross sections of a laminate (inorganic substrate / heat-resistant polymer film / protective film / protective film peeling aid tape) of the present invention. 3 is a diagram showing a schematic diagram of an example of a silane coupling agent treatment device used in the vapor deposition method of the present invention.

[0015] An embodiment of the present invention (hereinafter simply referred to as "embodiment") will be described in detail below. Note that the present invention is not limited to the following embodiment and can be practiced with various modifications within the scope of the gist thereof. <Heat-Resistant Polymer Film> Examples of the heat-resistant polymer film (hereinafter simply referred to as polymer film) include films of polyimide-based resins such as polyimide, polyamideimide, polyetherimide, and fluorinated polyimide (e.g., aromatic polyimide resins, alicyclic polyimide resins); polyolefin-based resins such as polyethylene and polypropylene; copolymerized polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate (e.g., wholly aromatic polyesters, semi-aromatic polyesters); copolymerized (meth)acrylates typified by polymethyl methacrylate; polycarbonate; polyamide; polysulfone; polyethersulfone; polyetherketone; cellulose acetate; cellulose nitrate; aromatic polyamide; polyvinyl chloride; polyphenol; polyarylate; polyphenylene sulfide; polyphenylene oxide; and polystyrene.

[0016] However, since the polymer films are intended to be used in processes involving heat treatment at 300°C or higher, only a limited number of the exemplified polymer films can actually be applied. Among the polymer films, preferred are films made of so-called super engineering plastics, more specifically, polyimide resins, polyamide resins, polyamideimide resins, and azole resins. Particularly preferred examples include aromatic polyimide films, aromatic amide films, aromatic amideimide films, aromatic benzoxazole films, aromatic benzothiazole films, and aromatic benzimidazole films.

[0017] A polyimide resin film (sometimes referred to as a polyimide film), which is an example of the polymer film, will be described in detail below. In general, a polyimide resin film is obtained by applying a polyamic acid (polyimide precursor) solution obtained by reacting a diamine with a tetracarboxylic acid in a solvent to a support for preparing the polyimide film, drying the solution to form a green film (hereinafter also referred to as a "polyamic acid film"), and further subjecting the green film to high-temperature heat treatment on the support for preparing the polyimide film or in a state where it has been peeled off from the support to cause a dehydration ring-closing reaction.

[0018] The polyamic acid (polyimide precursor) solution can be applied by any of the conventionally known solution application methods, such as spin coating, doctor blade, applicator, comma coater, screen printing, slit coating, reverse coating, dip coating, curtain coating, and slit die coating.

[0019] The diamines constituting the polyamic acid are not particularly limited, and aromatic diamines, aliphatic diamines, alicyclic diamines, etc., which are commonly used in polyimide synthesis, can be used. From the viewpoint of heat resistance, aromatic diamines are preferred. The diamines can be used alone or in combination of two or more.

[0020] The diamines are not particularly limited, and examples thereof include oxydianiline (bis(4-aminophenyl)ether), paraphenylenediamine (1,4-phenylenediamine), and the like.

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

[0022] The tetracarboxylic acid is not particularly limited, and examples thereof include pyrrolimetic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride.

[0023] The polyimide film may be a transparent polyimide film.

[0024] A colorless and transparent polyimide, an example of the polymer film, will now be described. Hereinafter, to avoid complication, it will also be referred to simply as transparent polyimide. The transparency of the transparent polyimide is preferably such that the total light transmittance is 75% or more, more preferably 80% or more, even more preferably 85% or more, even more preferably 87% or more, and particularly preferably 88% or more. There is no particular upper limit for the total light transmittance of the transparent polyimide, but for use as a flexible electronic device, it is preferably 98% or less, more preferably 97% or less. The colorless and transparent polyimide of the present invention is preferably a polyimide with a total light transmittance of 75% or more.

[0025] Examples of aromatic tetracarboxylic acids for obtaining colorless and highly transparent polyimides include 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid, 4,4'-oxydiphthalic acid, bis(1,3-dioxo-1,3-dihydro-2-benzofuran-5-carboxylic acid)1,4-phenylene, bis(1,3-dioxo-1,3-dihydro-2-benzofuran-5-yl)benzene-1,4-dicarboxylate, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(benzene-1,4-diyloxy)] ]dibenzene-1,2-dicarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 4,4'-[(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(1,4-xylene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(4 -isopropyl-toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(naphthalene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(benzene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-benzophenonetetracarboxylic acid, 4,4'-[(3H-2,1-benzo 4,4'-[(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(1,4-xylene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(4-isopropyl-toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(naphthalene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 3,3',4,4'-diphenylsulfonetetracarboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, pyromellitic acid, 4,4'-[spiro(xanthene-9,9'-fluorene)-2,6-diylbis(oxycarbonyl)]diphthalic acid, 4,4'-[spiro(xanthene-9,9'-fluorene)-3,6-diylbis(oxycarbonyl)]diphthalic acid, and tetracarboxylic acids such as these acid anhydrides. Among these, dianhydrides having two acid anhydride structures are preferred, and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic dianhydride and 4,4'-oxydiphthalic dianhydride are particularly preferred. The aromatic tetracarboxylic acids may be used alone or in combination of two or more. When heat resistance is important, the copolymerization amount of the aromatic tetracarboxylic acids is, for example, 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, and particularly preferably 90% by mass or more, and may even be 100% by mass.

[0026] Examples of 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]oct-7-ene-2,3,5,6-tetracarboxylic acid. carboxylic 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-spiro-α-cyclohexanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid pyro-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'', ,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 norbornane-2-spiro-α-(methylcyclohexanone)-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, and tetracarboxylic acids such as these acid anhydrides. Among these, dianhydrides having two acid anhydride structures are preferred, and in particular, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclohexanetetracarboxylic dianhydride, and 1,2,4,5-cyclohexanetetracarboxylic dianhydride are preferred, and 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2,4,5-cyclohexanetetracarboxylic dianhydride are more preferred, and 1,2,3,4-Cyclobutanetetracarboxylic dianhydride is more preferred. These may be used alone or in combination of two or more. When transparency is important, the copolymerization amount of the alicyclic tetracarboxylic acids is, for example, 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, and particularly preferably 90% by mass or more, and may even be 100% by mass.

[0027] Examples of tricarboxylic acids include aromatic tricarboxylic acids such as trimellitic acid, 1,2,5-naphthalenetricarboxylic acid, diphenylether-3,3',4'-tricarboxylic acid, and diphenylsulfone-3,3',4'-tricarboxylic acid, as well as hydrogenated products 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 monoanhydrides and esterified products thereof. Among these, monoanhydrides having one acid anhydride structure are preferred, with trimellitic anhydride and hexahydrotrimellitic anhydride being particularly preferred. These may be used alone 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, as well as hydrogenated versions of these aromatic dicarboxylic acids such as 1,6-cyclohexanedicarboxylic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, heptanedioic acid, octanedioic acid, azelaic acid, sebacic acid, undecadioic acid, dodecanedioic acid, and 2-methylsuccinic acid, as well as acid chlorides and esters thereof. Among these, aromatic dicarboxylic acids and hydrogenated versions thereof are preferred, with terephthalic acid, 1,6-cyclohexanedicarboxylic acid, and 4,4'-oxydibenzenecarboxylic acid being particularly preferred. The dicarboxylic acids may be used alone or in combination.

[0029] The diamines or isocyanates used to obtain colorless and highly transparent polyimides are not particularly limited, and aromatic diamines, aliphatic diamines, alicyclic diamines, aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and the like, which are commonly used in polyimide synthesis, polyamideimide 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, the use of aromatic diamines having a benzoxazole structure makes it possible to achieve high heat resistance, as well as a high elastic modulus, low heat shrinkage, and a low coefficient of linear expansion. Diamines and isocyanates can 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, 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)-3-methylphenyl]propane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)phenyl] 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 ton, 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)benzo yl]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]diphenyl sulfone, bis[4-{4-(4-aminophenoxy)pheno hydroxy}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'-diviphenoxybenzophenone, 4,4'-diamino-5,5'-diviphenoxybenzophenone, 3,4'-diamino-4,5'-diviphenoxybenzophenone, 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]benzoni 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, 4,4'-[spiro(xanthene-9,9'-fluorene)-3,6-diylbis(oxycarbonyl)]bisaniline, etc. In addition, some or all of the hydrogen atoms on the aromatic ring of the aromatic diamine may be substituted with halogen atoms, alkyl or alkoxy groups having 1 to 3 carbon atoms, or cyano groups, and further some or all of the hydrogen atoms of the alkyl or alkoxy groups having 1 to 3 carbon atoms may be substituted with halogen atoms. The aromatic diamines having a benzoxazole structure are not particularly limited, and examples thereof 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), 2,2'-p-phenylene Nylenebis(6-aminobenzoxazole), 1-(5-aminobenzoxazolo)-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,Examples of the aromatic diamines 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'-diaminodiphenyl sulfone, and 3,3'-diaminobenzophenone are particularly preferred. The aromatic diamines may be used alone 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 alone 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, 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, diphenylether-4,4' -diisocyanate, benzophenone-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-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 of the diisocyanate include aromatic diisocyanates such as ethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, and 3,3'-diethoxybiphenyl-4,4'-diisocyanate, and diisocyanates obtained by hydrogenating any of these (for example, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate).Among these, diphenylmethane-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, naphthalene-2,6-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,4-cyclohexane diisocyanate are preferred from the viewpoints of low moisture absorption, dimensional stability, cost, and polymerizability. The diisocyanates may be used alone or in combination.

[0033] In this embodiment, the polymer film is preferably a polyimide film. When the polymer film is a polyimide film, the polymer film has excellent heat resistance. Furthermore, when the polymer film is a polyimide film, it can be suitably cut with an ultraviolet laser.

[0034] The thickness of the polymer film is preferably 3 μm or more, more preferably 7 μm or more, even more preferably 14 μm or more, and even more preferably 20 μm or more. There is no particular upper limit to the thickness of the polymer film, but for use as a flexible electronic device, it is preferably 250 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0035] The average coefficient of linear expansion (CTE) of the polymer film between 30°C and 250°C is preferably 50 ppm / K or less. It is 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 respect to a typical support (inorganic substrate) can be kept small, and peeling between the polymer film and the inorganic substrate or warping of the support can be prevented even when subjected to a heat-applied process. Here, CTE is a factor that represents reversible expansion and contraction with temperature. The CTE of the polymer film refers to the average value of the CTE in the coating direction (MD) of the polymer solution or polymer precursor solution and the CTE in the width direction (TD).

[0036] When the polymer film is a transparent polyimide film, 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 still more preferably 3 or less. There is no particular lower limit for the yellowness index of the transparent polyimide, 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.

[0037] When the polymer film is a transparent polyimide film, the haze 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. There is no particular lower limit, but from an industrial perspective, a haze of 0.01 or more is acceptable, and even 0.05 or more is acceptable. The heat shrinkage rate of the polymer film between 30°C and 500°C is preferably ±0.9% or less, and more preferably ±0.6% or less. The heat shrinkage rate is a factor that indicates irreversible expansion and contraction with temperature.

[0038] The tensile breaking strength of the polymer film is preferably 60 MPa or more, more preferably 80 MPa or more, and even more preferably 100 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 peeling it from the inorganic substrate. The tensile breaking strength of the polymer film refers to the average value of the tensile breaking strength in the machine direction (MD) and the width direction (TD) of the polymer film.

[0039] The tensile breaking elongation of the polymer film is preferably 1% or more, more preferably 5% or more, and even more preferably 10% or more. When the tensile breaking elongation is 1% or more, the film has excellent handleability. The tensile breaking elongation of the polymer film refers to the average value of the tensile breaking elongation in the machine direction (MD) and the width direction (TD) of the polymer film.

[0040] The tensile modulus of the polymer film is preferably 2.5 GPa or more, more preferably 3 GPa or more, and even more preferably 4 GPa or more. When the tensile modulus is 2.5 GPa or more, the polymer film undergoes little elongation deformation when peeled from the inorganic substrate, resulting in excellent handleability. The tensile modulus is preferably 20 GPa or less, more preferably 15 GPa or less, and even more preferably 12 GPa or less. When the tensile modulus is 20 GPa or less, the polymer film can be used as a flexible film. The tensile modulus of the polymer film refers to the average value of the tensile modulus in the machine direction (MD direction) and the width direction (TD direction) of the polymer film.

[0041] The thickness unevenness of the polymer film 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 unevenness exceeds 20%, it tends to be difficult to apply to narrow sections. The thickness unevenness of the film can be calculated, for example, by measuring the film thickness at approximately 10 randomly selected positions on the film to be measured using a contact film thickness meter, and then using the following formula:

[0042] Film thickness unevenness (%) = 100 × (maximum film thickness - minimum film thickness) ÷ average film thickness The polymer film is preferably obtained in the form of a long polymer film wound up during production, with a width of 300 mm or more and a length of 10 m or more, and more preferably in the form of a rolled polymer film wound around a winding core. When the polymer film is wound up in a roll, it can be easily transported in the form of a rolled polymer film.

[0043] In order to ensure handleability and productivity, it is preferable to add or contain about 0.03 to 3 mass % of a lubricant (particles) having a particle diameter of about 10 to 1000 nm to the polymer film, thereby imparting fine irregularities to the surface of the polymer film and ensuring slipperiness. <Inorganic Substrate> The inorganic substrate may be any plate-like material that can be used as a substrate made of an inorganic material, and examples include those mainly composed of glass plates, ceramic plates, semiconductor wafers, metals, etc., and composites of these glass plates, ceramic plates, semiconductor wafers, and metals, such as laminates thereof, composites in which these are dispersed, and composites in which these fibers are contained.

[0044] Examples of the glass plate include quartz glass, high silicate glass (96% silica), soda-lime glass, lead glass, aluminoborosilicate glass, borosilicate glass (Pyrex (registered trademark)), borosilicate glass (alkali-free), borosilicate glass (microsheet), aluminosilicate glass, etc. Among these, those having a linear expansion coefficient of 5 ppm / K or less are desirable, and commercially available products such as liquid crystal glass "Corning (registered trademark) 7059", "Corning (registered trademark) 1737", and "EAGLE" manufactured by Corning Incorporated, "AN100" manufactured by Asahi Glass Co., Ltd., "OA10, OA11G" manufactured by Nippon Electric Glass Co., Ltd., and "AF32" manufactured by Schott GmbH are desirable.

[0045] The semiconductor wafer is not particularly limited, but examples include wafers of silicon wafers, germanium, silicon-germanium, gallium-arsenic, aluminum-gallium-indium, nitrogen-phosphorus-arsenic-antimony, SiC, InP (indium phosphide), InGaAs, GaInNAs, LT, LN, ZnO (zinc oxide), CdTe (cadmium telluride), ZnSe (zinc selenide), etc. Among these, the wafers that are preferably used are silicon wafers, and particularly preferred are mirror-polished silicon wafers having a size of 8 inches or more.

[0046] Examples of the metal include single-element metals such as W, Mo, Pt, Fe, Ni, and Au, as well as alloys such as Inconel, Monel, nimonic, copper carbon, Fe-Ni-based Invar alloys, and Super Invar alloys. Multilayer metal plates formed by adding other metal layers or ceramic layers to these metals are also included. In this case, Cu, Al, and the like can be used for the main metal layer as long as the overall coefficient of linear expansion (CTE) of the additional layer is low. The metal used for the additional metal layer is not limited as long as it has properties such as strong adhesion to the thermoset polyamic acid, no diffusion, and good chemical and heat resistance. Suitable examples include Cr, Ni, TiN, and Mo-containing Cu.

[0047] The ceramic plate in the present invention is Al ２ O ３ , Mullite, ALN, SiC, glass ceramics, Cordierite, Spodumene, Pb-BSG+CaZrO ３ +Al ２ O ３ ,Crystallized glass+Al ２ O ３、 Crystallized Ca-BSG, BSG+Quartz, BSG+Al ２ O ３ , Pb-BSG+Al ２ O ３ These include ceramics for substrates such as Glass-ceramic and Zerodur materials.

[0048] The thickness of the inorganic substrate is not particularly limited, but from the viewpoint of ease of handling, it is preferably 10 mm or less, 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 it 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 broken and difficult to handle. If it is too thick, it will be heavy and difficult to handle.

[0049] Surface treatment may be performed to improve the wettability and adhesion of the inorganic substrate. Examples of surface treatment agents that can be used include silane coupling agents, aluminum-based coupling agents, and titanate-based coupling agents. In particular, superior properties can be achieved when silane coupling agents are used. <Silane Coupling Agent (SCA)> It is preferable for the laminate to have a silane coupling agent layer (also referred to as a silane coupling agent condensation layer) between the polymer film layer and the inorganic substrate. In the present invention, a silane coupling agent refers to a compound containing 10% by mass or more of silicon (Si). The use of a silane coupling agent layer allows for a thinner intermediate layer between the thermoset polyamic acid layer and the inorganic substrate, resulting in fewer outgassing components during heating, less leaching during wet processes, and even if leaching does occur, only a trace amount. Silane coupling agents that contain a high content of silicon oxide are preferred for improved heat resistance, and those that are particularly heat-resistant at temperatures of around 400°C are preferred. The thickness of the silane coupling agent layer is preferably 200 nm or less (0.2 μm or less). The range for use in flexible electronic devices is preferably 100 nm or less (0.1 μm or less), more preferably 50 nm or less, and even more preferably 10 nm. In normal manufacturing, the thickness is about 0.10 μm or less. Furthermore, in processes where it is desired to use as little silane coupling agent as possible, even 5 nm or less can be used. If it is less than 0.1 nm, the peel strength may decrease or there may be areas where the silane coupling agent does not adhere. Therefore, it is preferably 0.1 nm or more, and more preferably 0.5 nm or more.

[0050] The silane coupling agent used in the present invention is not particularly limited, but is preferably one having an amino group or an epoxy group. When heat resistance is required in the process, it is desirable to use one in which the Si and amino group are linked by an aromatic group.

[0051] The silane coupling agent is not particularly limited, but preferably contains 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. <Protective Film> The laminate of the present invention contains a protective film laminated (attached) to the heat-resistant polymer film. The protective film to be laminated (attached) to the heat-resistant polymer film is usually a film for temporarily protecting the surface of the heat-resistant polymer film, and is not particularly limited as long as it is a peelable film that can protect the surface of the heat-resistant polymer film. In the present invention, it is preferable to select the protective film so that it satisfies formula (1) in consideration of ease of peeling in subsequent processes. For example, in addition to PET film, PEN film, polyethylene film, polypropylene film, nylon film, etc., heat-resistant super engineering plastic films such as PPS film, PEEK film, aromatic polyamide film, polyimide film, and polyimide benzasol film can be used. Among these, PET film is preferred.

[0052] In the laminate of the present invention, the arithmetic mean waviness Wa of the surface of the protective film in contact with the heat-resistant polymer film is preferably 30 nm or less. The arithmetic mean waviness Wa is a parameter representing the magnitude (amplitude) of the waviness in the height direction. Since the waviness that affects the adhesion to the heat-resistant polymer film consists of waviness with a period of several tens of μm, the measurement range of the interference microscope is preferably 60 μm or more in both the x and y directions.

[0053] In the present invention, the heat-resistant polymer film has a very smooth surface because it is intended that a device will be formed on the surface. When the arithmetic mean waviness Wa of the protective film surface in contact with the heat-resistant polymer film is 30 nm or less, sufficient adhesion to the heat-resistant polymer film can be ensured. Therefore, in the present invention, the arithmetic mean waviness Wa of the protective film is preferably 29 nm or less, more preferably 28 nm or less, and even more preferably 27 nm or less. The lower limit of the arithmetic mean waviness Wa of the protective film is not particularly limited, but is usually 5 nm or more.

[0054] The arithmetic mean waviness Wa of the protective film can be controlled by the manufacturing conditions (temperature, linear speed, surface waviness of the nip roll, nip pressure, etc.) during molding of the protective film. For example, the arithmetic mean waviness Wa tends to decrease when the molding temperature is lowered, and the arithmetic mean waviness Wa also tends to decrease by increasing the linear speed or lowering the nip pressure. It can also be controlled by the storage conditions (temperature, humidity, storage time) of the protective film after molding. When using a commercially available protective film, it is possible to select an appropriate one by measuring the arithmetic mean waviness Wa of the protective film to be used before laminating it with a transparent resin film.

[0055] The protective film preferably has a pressure-sensitive adhesive layer on the surface that contacts the heat-resistant polymer film layer. Having a pressure-sensitive adhesive layer on the protective film allows it to exhibit self-adsorption. The pressure-sensitive adhesive layer is not particularly limited, but examples of pressure-sensitive adhesive layers that can be used include urethane-based, silicone-based, and acrylic-based pressure-sensitive adhesive layers. The pressure-sensitive adhesive layer can be prepared by applying a pressure-sensitive adhesive dissolved in a solvent and drying it.

[0056] From the viewpoint of cost reduction, a self-adhesive resin film (protective film) such as a polyolefin resin may be used. Specifically, a polyolefin resin film is preferred. Because of their ease of availability and low cost, a polypropylene resin film or a polyethylene resin film is more preferred, and a polyethylene resin film is even more preferred. Examples of polyethylene resins include high-pressure low-density polyethylene (LDPE), linear short-chain branched polyethylene (LLDPE), medium-low-pressure high-density polyethylene (HDPE), and very low-density polyethylene (VLDPE). However, LLDPE is preferred as the resin on the surface adjacent to the heat-resistant polymer film from the viewpoints of adhesion to the heat-resistant polymer film and processability. The protective film may contain various additives in the base layer or adhesive layer as needed. Examples of such additives include fillers, antioxidants, light stabilizers, antigelling agents, organic wetting agents, antistatic agents, surfactants, pigments, and dyes. However, it is preferable that the protective film satisfy the following numerical ranges in ultraviolet transmittance measurement: When the protective film is composed of a substrate and a pressure-sensitive adhesive layer, the substrate preferably does not contain an ultraviolet absorber. Examples of the ultraviolet absorber include those described below.

[0057] In ultraviolet transmittance measurement (UV transmittance measurement), the protective film preferably has a 50% cutoff wavelength of ultraviolet transmittance of 240 nm or more, more preferably 270 nm or more, more preferably 300 nm or more, and particularly preferably 340 nm or more. When the 50% cutoff wavelength of ultraviolet transmittance of the protective film is 240 nm or more, the protective film and the heat-resistant polymer film can be more suitably cut with an ultraviolet laser. Therefore, the heat-resistant polymer film can be cut to any size with a laser from the inorganic substrate / heat-resistant polymer film / protective film laminate, or the heat-resistant polymer film with the protective film can be cut to any size with a laser. The upper limit is preferably 380 nm or less, which is the general wavelength range of ultraviolet light.

[0058] In order to achieve the above-mentioned ultraviolet transmittance, the protective film preferably contains an ultraviolet absorber, such as an organic ultraviolet absorber.

[0059] Examples of the organic ultraviolet absorber include benzotriazoles, benzophenones, cyclic imino esters, and combinations thereof. Among these, benzotriazoles and cyclic imino esters are particularly preferred from the viewpoint of durability.

[0060] Examples of the benzotriazole-based ultraviolet absorber include 2-[2'-hydroxy-5'-(methacryloyloxymethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxypropyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyhexyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-3'-tert-butyl-5'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole, and 2-[2'-hydroxy-5'-tert-butyl-3'-(methacryloyloxypropyl)phenyl]-2H-benzotriazole. 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-methoxy-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-cyano-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-tert-butyl-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-nitro-2H-benzotriazole, and the like.

[0061] Examples of the benzophenone-based ultraviolet absorber include 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-acetoxyethoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, and 2,2'-dihydroxy-4,4'-dimethoxy-5,5'-disulfobenzophenone disodium salt.

[0062] Examples of the cyclic imino ester-based ultraviolet absorbers include 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one), 2-methyl-3,1-benzoxazin-4-one, 2-butyl-3,1-benzoxazin-4-one, 2-phenyl-3,1-benzoxazin-4-one, 2-(1- or 2-naphthyl)-3,1-benzoxazin-4-one, 2-(4-biphenyl)-3,1-benzoxazin-4-one, 2-p-nitrophenyl-3,1-benzoxazin-4-one, 2-m-nitrophenyl-3,1-benzoxazin-4-one, and the like. Phenyl-3,1-benzoxazin-4-one, 2-p-benzoylphenyl-3,1-benzoxazin-4-one, 2-p-methoxyphenyl-3,1-benzoxazin-4-one, 2-o-methoxyphenyl-3,1-benzoxazin-4-one, 2-cyclohexyl-3,1-benzoxazin-4-one, 2-p-(or m-)phthalimidophenyl-3,1-benzoxazin-4-one, 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazinon-4-one), 2,2'-bis(3,1-benzoxazinon-4-one), 2,2'-ethylenebis(3,1-benzoxazin-4-one), 2,2'-tetramethylenebis(3,1-benzoxazin-4-one), 2,2'-decamethylenebis(3,1-benzoxazin-4-one), 2,2'-p-phenylenebis(3,1-benzoxazin-4-one), 2,2'-m-phenylenebis(3,1-benzoxazin-4-one), 2,2'-(4,4'-diphenylene)bis(3,1-benzoxazin-4-one), 2,2'-(2,6- or 1,5-naphthalene)bis(3,1-benzoxazin-4-one), phthalene)bis(3,1-benzoxazin-4-one), 2,2'-(2-methyl-p-phenylene)bis(3,1-benzoxazin-4-one), 2,2'-(2-nitro-p-phenylene)bis(3,1-benzoxazin-4-one), 2,2'-(2-chloro-p-phenylene)bis(3,1-benzoxazin-4-one), 2,2'-(1,4-cyclohexylene)bis(3,1-benzoxazin-4-one), 1,3,5-tri(3,1-benzoxazin-4-one-2-yl)benzene, and the like.

[0063] Also, 1,3,5-tri(3,1-benzoxazin-4-one-2-yl)naphthalene, 2,4,6-tri(3,1-benzoxazin-4-one-2-yl)naphthalene, 2,8-dimethyl-4H,6H-benzo(1,2-d;5,4-d')bis-(1,3)-oxazine-4,6-dione, 2,7-dimethyl-4H,9H-benzo(1,2-d;5,4-d')bis-(1,3)-oxazine-4,9-dione, 2,8-diphenyl-4H,8H-benzo(1,2-d;5,4-d')bis-(1,3)-oxazine-4,6-dione, 2 ,7-diphenyl-4H,9H-benzo(1,2-d;5,4-d')bis-(1,3)-oxazine-4,6-dione, 6,6'-bis(2-methyl-4H,3,1-benzoxazin-4-one), 6,6'-bis(2-ethyl-4H,3,1-benzoxazin-4-one), 6,6'-bis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6'-methylenebis(2-methyl-4H,3,1-benzoxazin-4-one), 6,6'-methylenebis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6'- Ethylenebis(2-methyl-4H,3,1-benzoxazin-4-one), 6,6'-ethylenebis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6'-butylenebis(2-methyl-4H,3,1-benzoxazin-4-one), 6,6'-butylenebis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6'-oxybis(2-methyl-4H,3,1-benzoxazin-4-one), 6,6'-oxybis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6'-sulfonylbis(2 -methyl-4H,3,1-benzoxazin-4-one), 6,6'-sulfonylbis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6'-carbonylbis(2-methyl-4H,3,1-benzoxazin-4-one), 6,6'-carbonylbis(2-phenyl-4H,3,1-benzoxazin-4-one), 7,7'-methylenebis(2-methyl-4H,3,1-benzoxazin-4-one), 7,7'-methylenebis(2-phenyl-4H,3,1-benzoxazin-4-one), 7,7'-bis(2-methyl-4H,3,1-benzoxazin-4-one), 7,7'-ethylenebis(2-methyl-4H,3,1-benzoxazin-4-one), 7,7'-oxybis(2-methyl-4H,3,1-benzoxazin-4-one), 7,7'-sulfonylbis(2-methyl-4H,3,1-benzoxazin-4-one), 7,7'-carbonylbis(2-methyl-4H,3,1-benzoxazin-4-one), 6, 7'-bis(2-methyl-4H,3,1-benzoxazin-4-one), 6,7'-bis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,7'-methylenebis(2-methyl-4H,3,1-benzoxazin-4-one), 6,7'-methylenebis(2-phenyl-4H,3,1-benzoxazin-4-one), and the like can also be used as cyclic imino ester-based ultraviolet absorbers.

[0064] <Release Aid Tape> In the present invention, the laminate comprises an inorganic substrate, a heat-resistant polymer film, a protective film, and a protective film release aid tape laminated in this order. The protective film release aid tape (hereinafter also referred to simply as release aid tape) is intended to aid in the release of the protective film from the heat-resistant polymer film, and basically comprises a substrate and a pressure-sensitive adhesive layer provided on the substrate surface. However, if the peel strength satisfies the relationship of formula (1), a resin film having self-adsorption such as a polyolefin resin may also be used.

[0065] The substrate of the peel aid tape can be, for example, a PET film, a PEN film, a polyethylene film, a polypropylene film, a nylon film, or a heat-resistant super engineering plastic film such as a PPS film, a PEEK film, an aromatic polyamide film, a polyimide film, or a polyimide benzalsol film.

[0066] The adhesive layer of the peeling aid tape is not particularly limited as long as it satisfies the relationship of formula (1), but for example, a urethane-based, silicone-based, or acrylic adhesive layer can be used. The adhesive layer can be produced by applying an adhesive dissolved in a solvent and drying it. Commercially available adhesive tapes that can be used include, for example, Cellotape (registered trademark) manufactured by Nichiban Co., Ltd., film cloth tape, Nitto Denko Corporation cloth adhesive tape, and vinyl tape.

[0067] When the release aid tape is composed of a substrate and a pressure-sensitive adhesive layer, the substrate thickness is preferably 30 μm or more, more preferably 50 μm or more. When the substrate thickness is 30 μm or more, handling properties are good. Since the release aid tape is easier to handle when wound in a roll, the upper limit of the thickness is preferably 400 μm or less, more preferably 200 μm or less. The same applies to the preferred thickness when the release aid tape is composed of a self-adhesive film.

[0068] When the peeling aid tape is composed of a substrate and a pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer is preferably 7 μm or more, and more preferably 10 μm or more. When the thickness of the pressure-sensitive adhesive layer is 7 μm or more, it is easy to ensure adhesion to the protective film. Furthermore, the thickness of the pressure-sensitive adhesive layer is preferably 20 μm or less. When the pressure-sensitive adhesive layer is 20 μm, the pressure applied when the pressure-sensitive adhesive layer is attached to the protective film does not cause the pressure-sensitive adhesive layer to protrude from the substrate, and the laminate is less likely to become soiled.

[0069] It is preferable that the area B2 of the peeling aid tape is smaller than the area B1 of the protective film (B1 > B2). Even when the areas B1 and B2 are equal (B1 = B2), the protective film can be peeled off as long as the relationship of formula (1) is satisfied. However, since the main effect of the protective film peeling aid tape is to lift the peeling edge of the protective film, the effect may be small if B1 = B2. Furthermore, even when the area B1 is smaller than the area B2 (B1 < B2), the protective film can be peeled off, but the adhesive layer of the peeling aid tape will come into contact with places other than the protective film, such as the inorganic substrate, and the laminate may be contaminated with transferred material from the adhesive.

[0070] The peeling aid tape is attached to the edge of the protective film of the heat-resistant polymer film / inorganic substrate laminate with a protective film (inorganic substrate / heat-resistant polymer film / protective film) as shown in Figure 1. The attached side may be one side as shown in Figures 1(a) to (d), but it may also be attached to two or more sides as shown in Figure 1(e), and the protective film may be peeled from two or more peeling edges.

[0071] When the release aid tape is attached so that it partially protrudes from the protective film as shown in Figure 1, it is preferable that the adhesive layer is not exposed in the portion that does not contact the protective film. If the adhesive layer is exposed, the adhesive layer of the release aid tape will also come into contact with places other than the protective film, such as the inorganic substrate, and the laminate may be contaminated with transferred material from the adhesive. Methods for preventing partial exposure of the adhesive layer include forming an adhesive layer only in the width of the release aid tape substrate that will be attached to the protective film, and attaching a non-adhesive film to the portion that protrudes from the protective film. <Laminate> The laminate of the present invention includes the inorganic substrate, the heat-resistant polymer film, the protective film, and the protective film peeling auxiliary tape in this order, and it is necessary that an adhesive strength F1 (hereinafter also simply referred to as F1) between the inorganic substrate and the heat-resistant polymer film measured by a 90-degree peeling method, an adhesive strength F2 (hereinafter also simply referred to as F2) between the heat-resistant polymer film and the protective film measured by a 90-degree peeling method, and an adhesive strength F3 (hereinafter also simply referred to as F3) between the protective film and the protective film peeling auxiliary tape measured by a 90-degree peeling method satisfy the relationship represented by the following formula (1).

[0072] F3>F1>F2 (1) By satisfying the above formula (1), it is possible to easily peel off only the protective film without peeling off the inorganic substrate and the polymer film, whether by manual peeling or mechanical peeling.

[0073] In the laminate of the present invention, if the peel strength F2 between the heat-resistant polymer film and the protective film is equal to or greater than the peel strength F1 between the inorganic substrate and the heat-resistant polymer film, it may be difficult to peel off the protective film alone. In particular, if the peel strength F1 between the inorganic substrate and the heat-resistant polymer film is low, the inorganic substrate and the polymer film may easily peel off when lifting the edge of the protective film. When the size of the laminate is small, this is not a major problem because it is possible to manually create a peel edge using release tape or peel off only the edge of the protective film with a jig such as tweezers. However, when handling in display manufacturing equipment, the size of the laminate of the inorganic substrate and the polymer film will be approximately 2 x 3 m at most. With laminates of this size, it is assumed that the protective film will be peeled off mechanically, and it is difficult to peel off only the protective film without peeling off the inorganic substrate and the protective film with delicate force, as in the case of manual peeling.

[0074] By using the configuration of the present invention, such problems can be avoided, and the laminate of the present invention allows the protective film alone to be peeled off without peeling the inorganic substrate and the protective film, whether manually or automatically.

[0075] In this specification, F1 and F2 refer to the 90° peel strength values ​​after a laminate (hereinafter also referred to as a laminate precursor) having an inorganic substrate, a heat-resistant polymer film, and a protective film laminated in this order is heat-treated at 120°C for 10 minutes in an atmospheric atmosphere (hereinafter also simply referred to as heat treatment). That is, the laminate precursor is a laminate before lamination (application) of a peel aid tape. The peel aid tape may be laminated (application) before or after the heat treatment of the laminate precursor. However, it is preferable to laminate (application) the laminate precursor after the heat treatment. Therefore, F3 refers to the 90° peel strength value before the heat treatment. F1 is not particularly limited as long as it satisfies the formula (1), but is preferably 0.05 N / cm or more, more preferably 0.08 N / cm or more, and even more preferably 0.1 N / cm or more. Furthermore, it is preferably 0.3 N / cm or less, and more preferably 0.28 N / cm or less. When F1 is 0.05 N / cm or more, peeling of the heat-resistant polymer film from the inorganic substrate before or during device formation can be prevented. Furthermore, when F1 is 0.3 N / cm or less, peeling of the inorganic substrate and the heat-resistant polymer film can be facilitated after device formation. In other words, when F1 is 0.3 N / cm or less, even if the peel strength between the inorganic substrate and the heat-resistant polymer film increases somewhat during device formation, the two can be easily peeled from each other.

[0076] The F2 is not particularly limited as long as it satisfies the formula (1), but is preferably 0.001 N / cm or more, more preferably 0.002 N / cm or more, and even more preferably 0.005 N / cm or more. Furthermore, it is preferably 0.1 N / cm or less, and more preferably 0.08 N / cm or less. When F2 is 0.1 N / cm or less, the protective film can be suitably peeled off when using the heat-resistant polymer film. Furthermore, when F2 is 0.001 N / cm or more, unintentional peeling of the protective film from the heat-resistant polymer film can be suppressed before the heat-resistant polymer film is used (for example, during transportation, etc.).

[0077] In the present invention, the rate of change in F2 before and after the heat treatment (heat treatment at 120°C for 10 minutes) is preferably 50% or less. Because this reduces the risk of contamination of the heat-resistant polymer film due to peeling of the protective film or thermal changes (deterioration) of the adhesive of the protective film during the laminate production process, the rate of change is more preferably 40% or less, and even more preferably 30% or less. The lower limit is not particularly limited, but is preferably -20% or more, more preferably -10% or more, and even more preferably -5% or more. The rate of change in F2 can be calculated using the following formula: Rate of change in F2 (%) = (F2 after heat treatment - F2 before heat treatment) / F2 before heat treatment × 100. It is preferable that F2 satisfy the relationship F1 > F2 even before the heat treatment (heating at 120°C for 10 minutes). This relationship allows the protective film to be easily peeled off without peeling the inorganic substrate and polymer film, even when the step of heating the laminate is omitted. The F3 is not particularly limited as long as it satisfies the formula (1), but is preferably 0.1 N / cm or more, more preferably 0.15 N / cm or more, and even more preferably 0.18 N / cm or more. The upper limit is not particularly specified, but is preferably 15 N / cm or less, and more preferably 13 N / cm or less. By having the F3 within the above range, the protective film can be suitably peeled off without peeling the inorganic substrate and the heat-resistant polymer film.

[0078] The ratio of F1 to F2 (F1 / F2) must be greater than 1, and is preferably 2 or more, more preferably 5 or more, and even more preferably 10 or more. In addition, it is preferably 100 or less, more preferably 80 or less, and even more preferably 60 or less.

[0079] The ratio of F3 to F1 (F3 / F1) must be greater than 1, preferably 1.1 or greater, more preferably 1.3 or greater, and even more preferably 1.4 or greater. It is also preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. <Method for Manufacturing Laminate> FIG. 2 is a cross-sectional view schematically showing a laminate according to this embodiment. FIG. 2( a) shows an example in which the adhesive layer 15 of the protective film peeling aid tape is laminated to a portion of the substrate 16 of the protective film peeling aid tape (the adhesive layer 15 is present only in the overlapping portion between the substrate 16 and the protective film 13), and FIG. 2( b) shows an example in which the adhesive layer 15 of the protective film peeling aid tape is laminated to the entire substrate 16 of the protective film peeling aid tape. FIG. 2( c) shows an example in which the adhesive layer 15 of the protective film peeling aid tape is laminated to the front portion of the substrate 16 of the protective film peeling aid tape, and an adhesive layer-covered film 17 of the protective film peeling aid tape is attached to the portion other than the overlapping portion with the protective film 13.

[0080] 2, the laminate according to this embodiment includes a protective film peeling auxiliary tape 11, a protective film 13, a heat-resistant polymer film 14, and an inorganic substrate 12. The inorganic substrate 12 and the heat-resistant polymer film 14 are laminated in contact with each other or laminated via only a silane coupling agent layer (not shown). The protective film peeling auxiliary tape 11 includes a protective film peeling auxiliary tape adhesive layer 15 and a protective film peeling auxiliary tape substrate 16.

[0081] The laminate according to this embodiment can be produced, for example, by the following procedure.

[0082] First, a heat-resistant polymer plastic film with a protective film and an inorganic substrate are prepared. When a heat-resistant polymer film with a protective film is used, the protective film on the surface of the heat-resistant polymer film with a protective film attached to the inorganic substrate is peeled off to obtain a heat-resistant polymer film with a one-sided protective film. When a silane coupling agent layer is provided on the laminate, at least one surface of the inorganic substrate is treated with a silane coupling agent.

[0083] Next, one surface of the inorganic substrate (the surface treated with the silane coupling agent if a silane coupling agent layer is provided) is superimposed on the heat-resistant polymer film with a protective film, and the two are pressed and heated to obtain a heat-resistant polymer film / inorganic substrate laminate (laminate precursor) with a protective film. It is also possible to obtain a heat-resistant polymer film / inorganic substrate laminate (laminate precursor) with a protective film by first treating the surface of the heat-resistant polymer film on which the protective film is not provided with a silane coupling agent, superimposing the silane coupling agent-treated surface on the inorganic substrate, and laminating the two by pressing and heating. A protective film peeling auxiliary tape can be attached to the protective film surface of the obtained heat-resistant polymer film / inorganic substrate (laminate precursor) to obtain a heat-resistant polymer film / inorganic substrate (laminate) with a protective film and a peeling auxiliary tape.

[0084] As a method for applying a silane coupling agent, known methods such as spin coating, spray coating, and dip coating can be used. Alternatively, the treatment can be performed by heating the silane coupling agent to generate silane coupling agent vapor and depositing the vapor onto the inorganic substrate (vapor phase deposition method).

[0085] FIG. 3 is a diagram showing a schematic diagram of an example of a silane coupling agent treatment device used in the vapor phase deposition method.

[0086] As shown in FIG. 3 , the silane coupling agent treatment device includes a treatment chamber 36 connected to a gas inlet 32, an exhaust port 38, and a chemical tank (silane coupling agent tank) 33. The chemical tank (silane coupling agent tank) 33 is filled with a silane coupling agent, and its temperature is controlled by a hot water bath (water bath) 34 equipped with a heater 35. A gas inlet 39 is connected to the chemical tank (silane coupling agent tank) 33, allowing gas to be introduced from outside. The gas flow rate is adjusted by a flow meter 31 connected to the gas inlet 39. When gas is introduced through the gas inlet 39, the vaporized silane coupling agent in the chemical tank 33 is pushed into the treatment chamber 36 and deposited as a silane coupling agent layer on a substrate 37 (an inorganic substrate or a heat-resistant polymer film) placed in the treatment chamber 36.

[0087] The pressurization method includes ordinary pressing or lamination in the atmosphere or pressing or lamination in a vacuum. However, in order to obtain stable peel strength over the entire surface, lamination in the atmosphere is desirable for large-sized laminates (e.g., over 200 mm). On the other hand, pressing in a vacuum is preferred for small-sized laminates of approximately 200 mm or less. A vacuum of approximately 10 Torr or less is sufficient using a conventional oil rotary pump. A preferred pressure is 1 MPa to 20 MPa, more preferably 3 MPa to 10 MPa. High pressures may damage the substrate, while low pressures may result in areas where the film is not adhered. A preferred temperature is 90°C to 300°C, more preferably 100°C to 250°C. High temperatures may damage the heat-resistant polymer film, while low temperatures may result in weak adhesion.

[0088] The shape of the laminate is not particularly limited, and may be square or rectangular. A rectangular shape is preferred, with the length of the long side being 300 mm or more, more preferably 500 mm or more, and even more preferably 1000 mm or more. The upper limit is not particularly limited, but industrially, 20,000 mm or less is sufficient, and 10,000 mm or less is also acceptable. Furthermore, the diameter of the circumscribed circle of the inorganic substrate is preferably 310 mm or more. Since even large laminates of the present invention can be packaged in stack form for storage and transportation, the diameter is more preferably 350 mm or more, and even more preferably 400 mm or more. Industrially, 30,000 mm or less is sufficient, and 20,000 mm or less is also acceptable.

[0089] <Adhesive> It is preferable that substantially no adhesive layer is interposed between the inorganic substrate and the heat-resistant polymer film layer of the present invention. Here, the adhesive layer referred to in the present invention refers to one containing less than 10% (less than 10 mass%) of Si (silicon) 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.

[0090] The timing for attaching the peeling aid tape to the heat-resistant polymer film with a protective film / inorganic substrate laminate (laminate precursor) may be immediately after the heat-resistant polymer film with a protective film and the inorganic substrate are bonded together, or may be after the heat-resistant polymer film with a protective film / inorganic substrate laminate is heated.

[0091] 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 physical properties in the following examples were evaluated using the following methods. <Heat-Resistant Polymer Film A1> Xenomax (registered trademark) F15LR2 (a polyimide film, 15 μm thick, manufactured by Toyobo Co., Ltd.) was used as the heat-resistant polymer film A1. <Heat-Resistant Polymer Film A2> 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 to a reaction vessel equipped with a nitrogen inlet tube, a Dean-Stark tube, a reflux tube, a thermometer, and a stirrer while introducing nitrogen gas. Subsequently, 31.02 parts by mass of 4,4'-oxydiphthalic acid dihydrate (ODPA), 24 parts by mass of GBL, and 13 parts by mass of toluene were added at room temperature, and the internal temperature was raised to 160°C. The mixture was heated to reflux at 160°C for 1 hour to carry out imidization. After completion of imidization, the temperature was raised to 180°C, and the reaction was continued while removing the toluene. After reaction for 12 hours, the oil bath was removed and the mixture was returned to room temperature, and GBL was added so that the solids concentration was 20% by mass, yielding a polyimide solution A1 with a reduced viscosity of 0.70 dl / g.

[0092] The resulting polyimide solution A1 was coated onto the non-slip surface of polyethylene terephthalate film A4100 (support manufactured by Toyobo Co., Ltd.) using a comma coater to a final film thickness of 25 μm. The polyethylene terephthalate film A04100 was passed through a hot air oven and wound up, during which it was dried at 100°C for 10 minutes. After drying, the self-supporting polyimide film was peeled from the support and passed through a pin tenter equipped with a pin sheet. The film edges were inserted into the pins to hold the film. The pin sheet spacing was adjusted to prevent film breakage and unnecessary slack. The film was then heated at 200°C for 3 minutes, 250°C for 3 minutes, and 300°C for 6 minutes to allow the imidization reaction to proceed. The film was then cooled to room temperature over 2 minutes, and the poorly flat portions of both ends of the film were trimmed off using a slitter. The film was then wound up into a roll to obtain 500 m of polyimide film A2 with a width of 450 mm. <Heat-Resistant Polymer Film A3> After the atmosphere in a reaction vessel equipped with a nitrogen inlet tube, a reflux condenser, and a stirrer was replaced with nitrogen, 33.36 parts by mass of 2,2'-bis(trifluoromethyl)benzidine (TFMB), 270.37 parts by mass of N-methyl-2-pyrrolidone (NMP), and a dispersion of colloidal silica dispersed in dimethylacetamide ("Snowtex (registered trademark) DMAC-ST" manufactured by Nissan Chemical Industries, Ltd.) were added and completely dissolved in an amount of 0.14% by mass of silica based on the total polymer solids in the polyamic acid solution, and then 9.81 parts by mass of 1,2,3,4-cyclobutanetetracarboxylic acid non-dihydrate (CBDA), 11.34 parts by mass of 3,3',4,4'-biphenyltetracarboxylic acid (BPDA), and 4.85 parts by mass of 4,4'-oxydiphthalic acid non-dihydrate (ODPA) were added in portions as solids, and the mixture was stirred at room temperature for 24 hours. Thereafter, 165.7 parts by mass of DMAc was added for dilution to obtain a polyamic acid solution B1 (molar ratio of TFMB / CBDA / BPDA / ODPA=1.00 / / 0.48 / 0.37 / 0.15) having a solid content of 18% by mass and a reduced viscosity of 2.7 dl / g.

[0093] The resulting polyamic acid solution B1 was applied to the non-slip surface of a polyethylene terephthalate film A4100 (manufactured by Toyobo Co., Ltd.) using a comma coater to a final film thickness of 25 μm. This was dried at 110°C for 10 minutes. After drying, the self-supporting polyamic acid film was peeled from the A4100 film that had been used as the support, passed through a pin tenter with a pin sheet, and the film edges were gripped by inserting them into the pins. The pin sheet spacing was adjusted to prevent the film from breaking and to prevent unnecessary sagging, and the film was transported. The film was heated at 200°C for 3 minutes, 250°C for 3 minutes, 300°C for 3 minutes, and 350°C for 3 minutes to allow the imidization reaction to proceed. The film was then cooled to room temperature over 2 minutes, and the poorly flat portions of both ends of the film were cut off using a slitter. The film was then wound into a roll, yielding 500 m of a 450 mm wide polyimide film A3. <Protective Film PF1> The following ingredients were mixed to obtain a pressure-sensitive adhesive composition C1.

[0094] Linear polyorganosiloxane having vinyl groups only at both ends (solvent-free, Mw: 80,000): 68.30 parts by mass Organohydrogenpolysiloxane (solvent-free, Mw: 2,000): 0.41 parts by mass Platinum catalyst (Shin-Etsu Chemical Co., Ltd., PL-56): 1.00 parts by mass Ultraviolet absorber (Cyasorb UV-3638 (CYTEC Co., Ltd.)): 0.3 parts by mass Reaction controller (3-methyl-1-butyn-3-ol): 0.10 parts by mass Toluene: 30.19 parts by mass Toyobo Co., Ltd. A polyethylene terephthalate (PET) film (A4100, thickness 50 μm) was subjected to corona treatment as a base treatment, and immediately after the corona treatment, the pressure-sensitive adhesive composition C1 was applied to the PET film. The coating was performed in an environment of 25°C and 85% RH, so that the thickness after drying was 10 μm. The coating was then heated in an oven at 150°C for 100 seconds to crosslink the film, resulting in a pressure-sensitive adhesive layer. This resulted in a protective film PF1. <Protective film PF2> 55.3 parts by weight of polyol (trifunctional, polyol obtained by addition polymerization of propylene oxide and ethylene oxide with glycerin, Sannix (registered trademark) GL3000 manufactured by Sanyo Chemical Industries, Ltd.), 4.7 parts by weight of Duranate D101 (polyisocyanate manufactured by Asahi Kasei Chemicals Corporation), 39.7 parts by weight of toluene, and 0.02 parts by weight of dibutyltin dilaurate (DBTDL) were placed in a separable flask and heated with stirring at 45°C to 55°C for 2 hours to allow the reaction to occur. After 2 hours of heating, the mixture was cooled to 40°C or below. After cooling, 0.28 parts by mass of an antioxidant was added and stirred until uniform, yielding polyurethane polyol-containing composition 1. 7.7 parts by mass of Duranate D101, 2 parts by mass of an ultraviolet absorber (Cyasorb UV-3638 (manufactured by CYTEC Corporation)), and 50 parts by mass of ethyl acetate were blended with 100 parts by mass of polyurethane polyol-containing composition 1, and the mixture was thoroughly stirred. The resulting pressure-sensitive adhesive composition was filtered through a PTFE cartridge filter (0.45 μm) to yield pressure-sensitive adhesive composition C2.

[0095] The pressure-sensitive adhesive composition C2 was applied to a polyethylene terephthalate (PET) film (A4100) manufactured by Toyobo Co., Ltd., which had previously been subjected to a corona treatment, so that the pressure-sensitive adhesive film thickness upon drying was 10 μm. The film was then heated and dried at 130°C for 2 minutes and then left to stand in a thermostatic chamber at 40°C for 3 days (aging process) to cure (crosslink) the pressure-sensitive adhesive, producing protective film PF2. <Protective Film PF3> 1.5 parts by weight of Coronate HX (manufactured by Tosoh Corporation, paint polyisocyanate) as a polyfunctional isocyanate and 0.3 parts by weight of KP-341 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd., polyether-modified organosiloxane) as a modified organosiloxane were added to 100 parts by weight of an acrylic polymer (a copolymer of 2-ethylhexyl acrylate and 4-hydroxybutyl acrylate (copolymerization ratio 100:8), weight-average molecular weight: 200,000), and the mixture was stirred and mixed to obtain pressure-sensitive adhesive composition C3.

[0096] The obtained adhesive composition C3 was applied to a polyethylene terephthalate (PET) film (A4100) manufactured by Toyobo Co., Ltd. that had been previously subjected to a corona treatment, and the film was dried at 100°C to remove the solvent, thereby obtaining a surface protection film PF3 in which a 10 μm-thick adhesive layer was formed on the PET film.

[0097] <Protective Film PF4> 100 parts by weight of urethane-based solvent-based pressure-sensitive adhesive US-902-50 (manufactured by Lion Specialty Chemicals, ethyl acetate solvent, solids content 50% by weight) was stirred while adding 5.4 parts by weight of Crosslinker N (manufactured by Lion Specialty Chemicals) and 2 parts by weight of UV absorber (Cyasorb UV-3638 (manufactured by Cytec Corporation)), and the mixture was allowed to react at 40°C for 20 minutes. The resulting solution was filtered through a PTFE cartridge filter (0.45 μm) and then coated onto a polyethylene terephthalate (PET) film (A4100) manufactured by Toyobo Co., Ltd. that had been corona-treated in advance to a final film thickness of 10 μm. The film was then heated at 100°C for 2 minutes to obtain protective film PF4. <Protective Film PF5> Toray Processing Film Co., Ltd.'s Toretek (registered trademark) 7832C was used for protective film PF5. <Protective Film PF6> The following ingredients were mixed to obtain a pressure-sensitive adhesive composition.

[0098] Linear polyorganosiloxane (solvent-free, Mw: 80,000) having vinyl groups only at both ends: 68.30 parts by mass Organohydrogenpolysiloxane (solvent-free, Mw: 2,000): 0.41 parts by mass Platinum catalyst (Shin-Etsu Chemical Co., Ltd., PL-56): 1.00 parts by mass Reaction inhibitor (3-methyl-1-butyn-3-ol): 0.10 parts by mass Toluene: 30.19 parts by mass Corona treatment was performed as a base treatment on Cosmoshine SRF (registered trademark, TA044, 80 μm) manufactured by Toyobo Co., Ltd., and the pressure-sensitive adhesive composition was applied immediately after the corona treatment. The application was performed in an environment of 25 ° C and 85% RH, so that the thickness after drying was 10 μm. Thereafter, the film was heated in an oven at 150 ° C for 100 seconds, crosslinked, and a pressure-sensitive adhesive layer was obtained. As a result of the above, a protective film PF6 was obtained. <Protective Film PF7> This was prepared in the same manner as Protective Film PF6, except that Ester (registered trademark) film (HB3, 50 μm) manufactured by Toyobo Co., Ltd. was used as the substrate. <Protective Film Peeling Aid Tape S1> SUNYTECT (registered trademark) SAT type manufactured by San-A Chemical Co., Ltd. was cut to a length of 300 mm x a width of 150 mm. A polyethylene terephthalate (PET) film (12 μm, E5100) manufactured by Toyobo Co., Ltd., having a length of 300 mm x a width of 50 mm, was attached to the adhesive surface to obtain Protective Film Peeling Aid Tape S1, in which the adhesive surface was exposed in a length of 300 mm x a width of 100 mm. <Protective Film Peeling Aid Tape S2> PF1 was cut to a length of 300 mm x a width of 150 mm. A 300 mm long x 50 mm wide polyethylene terephthalate (PET) film (12 μm, E5100) manufactured by Toyobo Co., Ltd. was attached to the adhesive surface to obtain a protective film peeling aid tape S2 with an exposed adhesive surface measuring 300 mm long x 100 mm wide. <Protective Film Peeling Aid Tape S3> Protective film peeling aid tape S3 was obtained in the same manner as S2, except that PF2 was used instead of PF1. <Protective Film Peeling Aid Tape S4> Protective film peeling aid tape S4 was obtained in the same manner as S2, except that PF3 was used instead of PF1. <Laminate Preparation> (Example 1) First, a glass substrate was prepared as the inorganic substrate. The glass substrate was OA10G glass (manufactured by NEG Co., Ltd.) with a thickness of 0.7 mm cut to a size of 500 mm x 500 mm.The glass substrate was washed with pure water, dried, and then exposed to UV light. ３ The glass substrate was cleaned by irradiating it with an irradiator (SKR1102N-03 manufactured by LAN Technical) for 1 minute. Next, a silane coupling agent (SCA) was applied to the glass substrate using a vapor-phase coating method to form a silane coupling agent layer, thereby obtaining a first laminate. Specifically, the application of the silane coupling agent to the glass substrate was performed using the experimental apparatus shown in Figure 3. Figure 3 is a schematic diagram of the experimental apparatus used to apply the silane coupling agent to the glass substrate. 130 g of 3-aminopropyltrimethoxysilane (KBM-903 manufactured by Shin-Etsu Chemical Co., Ltd.) was placed in a 1 L chemical tank, and the outer water bath was heated to 42°C. The resulting vapor was then sent to the chamber along with clean dry air. The gas flow rate was 22 L / min, and the substrate temperature was 21°C. The temperature of the clean dry air was 23°C and 1.2% RH. Because the exhaust was connected to a negative pressure exhaust port, a differential pressure gauge confirmed that the chamber was at a negative pressure of approximately 2 Pa.

[0099] First, PF1 was attached to both sides of polyimide film A1, and the film was cut to 300 mm x 300 mm. The protective film on the surface to be bonded to the support (glass substrate) was peeled off. PF1 was attached primarily to the surface to be bonded to the glass substrate in order to prevent scratches and foreign matter adhesion during the cutting process. The silane coupling agent layer of the silane coupling agent-treated glass substrate and the heat-resistant polymer film surface of the heat-resistant polymer film with the protective film were bonded together to obtain a laminate in which the glass substrate, silane coupling agent layer, heat-resistant polymer film, and protective film were laminated in this order. A laminator (MRK-1000 manufactured by MCK Corporation) was used for the bonding, and the bonding conditions were: original air pressure: 0.7 MPa, temperature: 22°C, humidity: 55% RH, and lamination speed: 50 mm / sec.

[0100] The obtained heat-resistant polymer film / glass substrate laminate with the protective film was heated in an oven in the atmosphere for 10 minutes at 120° C. A release aid tape was attached to the obtained laminate precursor as shown in FIG. 1( b) to obtain a release aid tape / protective film / heat-resistant polymer film / glass substrate laminate.

[0101] For Examples 2 to 9 and Comparative Examples 1 to 3, samples were prepared in the same manner by changing the combinations of the heat-resistant polymer film, protective film, and release aid tape used. The combinations are shown in Table 1.

[0102]

[0103] <90° Peel Strength> The 90° peel strength of each layer of the laminate obtained as described above was measured under the following conditions.

[0104] The inorganic substrate / heat-resistant polymer film and heat-resistant polymer film / protective film were heated at 120°C for 10 minutes, and then peeled. The heat-resistant polymer film / protective film (before heating) and protective film / protective film peeling aid tape were peeled off in an unheated state. When only the target layer could not be peeled off, the lower layer was firmly fixed with tape and then measurement was performed. The results are shown in Table 1.

[0105] Measuring device: Autograph AG-IS manufactured by Shimadzu Corporation Measuring temperature: room temperature (25° C.) Peeling speed: 100 mm / min Atmosphere: air Measurement sample width: 5 cm Measurement was carried out five times, and the average value was taken as the measured value.

[0106] When F3 > F1 > F2 (1) was satisfied, it was evaluated as O; when it was not, it was evaluated as ×. <Protective Film Peelability> The glass of the peeling aid tape / protective film / heat-resistant polymer film / glass substrate laminate was fixed to a workbench using double-sided tape. The peeling aid tape was grasped and peeling was performed at an angle of approximately 180°. Evaluation was performed by evaluating as O when the protective film could be peeled from the heat-resistant polymer film without peeling the heat-resistant polymer film from the glass substrate, and by evaluating as × when the heat-resistant polymer film peeled from the glass or when only the protective film peeling aid tape peeled. The results are shown in Table 1. <Ultraviolet (UV) 50% Cutoff Wavelength of Protective Film> UV transmittance was measured for protective films PF1 to 7. Specifically, UV transmittance was measured by a transmission method using a UV-3150 manufactured by Shimadzu Corporation. The wavelength at which transmittance was 50% was defined as the UV 50% cutoff wavelength. The results are shown in Table 1. <Wa of the surface of the protective film attached to the heat-resistant polymer film> The surface shape of the surface of the protective film attached to the heat-resistant polymer film was measured at 5x magnification using a Hitachi High-Technologies VS1800 scanning white microscope. The protective film was peeled from the heat-resistant polymer film at a 90° angle at 100 mm / min and allowed to stand for 5 minutes. The measurement range was 1404 μm in the x direction and 1872 μm in the y direction. The arithmetic mean waviness Wa was obtained using a waviness analysis function with a cutoff value of 20 μm. <Laser-cutting quality of the heat-resistant polymer film with protective film> Each of the prepared heat-resistant polymer films with protective film was irradiated with an ultraviolet laser from the protective film side to obtain a 100 mm x 100 mm size. The ultraviolet laser irradiation was performed without peeling the protective film from the heat-resistant polymer film. The ultraviolet laser used was a pulsed laser with a wavelength of 355 nm manufactured by Takei Electric Co., Ltd. The same location was scanned three times at a power of 8.5 W, a pulse frequency of 1000 kHz, and a scan speed of 500 mm / sec, whereby the first protective film and the polyimide film were cut into a piece measuring 100 mm x 100 mm.

[0107] After cutting, the laser-cut edges of the heat-resistant polymer film with the protective film were observed under a microscope, and the width of the black powder (smear) from the edge was measured. If the smear width was 300 μm or less, it was evaluated as ◯; if it was more than 300 μm and 500 μm or less, it was evaluated as △; if it was more than 500 μm, it was evaluated as ×. The results are shown in Table 1.

[0108] As described above, the laminate of the present invention (inorganic substrate / heat-resistant polymer film / protective film / protective film peeling aid tape laminate) can be handled with the heat-resistant polymer film surface protected by the protective film, and the protective film can be peeled off without any problems when processing the heat-resistant polymer film surface. The present invention can be usefully used in the manufacture of flexible devices, etc., by using such a laminate to perform microfabrication on a polymer film and then peeling the polymer film from an inorganic substrate. In particular, the present invention can be effectively used in display applications where the laminate size is large and automated protective film peeling is essential.

[0109] REFERENCE SIGNS LIST 11 protective film peeling aid tape 12 inorganic substrate 13 protective film 14 heat-resistant polymer film 15 adhesive layer of protective film peeling aid tape 16 substrate of protective film peeling aid tape 17 adhesive layer-coated film of protective film peeling aid tape 31 flow meter 32 gas inlet 33 chemical tank (silane coupling agent tank) 34 hot water bath (water bath) 35 heater 36 treatment chamber (chamber) 37 substrate 38 exhaust port

Claims

1. The present invention includes, in this order, an inorganic substrate, a heat-resistant polymer film, a protective film, and a protective film peeling auxiliary tape, an adhesive strength F1 between the inorganic substrate and the heat-resistant polymer film by a 90-degree peeling method; The adhesive strength F2 between the heat-resistant polymer film and the protective film by a 90-degree peeling method; The adhesive strength F3 between the protective film and the protective film peeling auxiliary tape by a 90 degree peeling method is F3>F1>F2 (1) A laminate characterized in that:

2. 2. The laminate according to claim 1, wherein the protective film has an ultraviolet 50% cutoff wavelength of 240 nm or more.

3. 3. The laminate according to claim 1, wherein the rate of change in F2 in the laminate before and after heating at 120° C. for 10 minutes is 50% or less.

4. 3. The laminate according to claim 1, wherein an area B1 of the protective film and an area B2 of the protective film peeling auxiliary tape satisfy a relationship of B1>B2.

5. 3. The laminate according to claim 1, wherein the surface of the protective film in contact with the heat-resistant polymer film has an arithmetic mean waviness Wa of 30 nm or less.

6. 3. The laminate according to claim 1, wherein the heat-resistant polymer film comprises at least one material selected from the group consisting of polyimide, polyamide, and polyamideimide.

7. 3. The laminate according to claim 1, wherein the heat-resistant polymer film is a transparent polyimide film.