JP2023001599A - laminate - Google Patents

Abstract

To provide a laminate including a transparent resin film based on a polyimide-based high polymer having a good exterior appearance and visibility and an excellent laser cutting property in which the whitening of a surface of the film is hard to occur.SOLUTION: A laminate is formed by laminating a transparent resin film and a protective film in this order. The transparent resin film contains resin and a solvent. The resin is at least one kind selected from a group consisting of polyimide, polyamide, and polyamide-imide. The solvent is N,N-dimethylacetamide. In the laminate, a product (S×W) of a residual solvent amount S (mass%) of the transparent resin film and a low-molecular component amount W (%) of the protective film is 4.7 or less (note that, W>0.33 and S≤5).SELECTED DRAWING: None

Description

The present invention relates to laminates. More particularly, it relates to a laminate of a transparent resin film and a protective film.

In recent years, as the displays of various image display devices have become thinner, lighter, and more flexible, transparent resin films based on polymers such as polyimide and polyamide have been widely used as materials to replace conventionally used glass. . A casting method (solution drooling method) is known as one of the methods for producing such a transparent resin film. In the casting method, generally, a varnish containing a polymer such as polyimide dissolved in a solvent is coated on a supporting substrate to form a film, peeled off from the supporting substrate, and then dried to remove the solvent, thereby forming a resin. Films can be continuously formed. A peelable protective film is appropriately laminated on the surface of the formed transparent resin film to protect the film surface (Patent Documents 1 to 3).

JP 2010-208312 A JP 2015-214122 A JP 2016-87799 A

If a solvent is present in the resin film, the components such as additives contained in the protective film may be eluted into the solvent contained in the resin film. surface may be whitened. In particular, in transparent resin films produced using a solvent by a casting method or the like, it is difficult to completely remove the solvent in the varnish during continuous production, and a certain amount of the solvent often remains. , whitening tends to occur when laminated with a protective film. Such whitening in a transparent resin film not only becomes a defect in the appearance of the transparent resin film, which requires high transparency, but also causes deterioration in visibility when used for displays such as various image display devices. Become.

Moreover, the transparent resin film mentioned above is supplied in the form wound up in roll shape in the state in which the protective film was affixed. To use this transparent resin film, first, the transparent resin film to which the protective film is attached is cut into a desired size and shape using a knife such as a Thomson type.

Cutting with a blade as described above deforms the cut portion because it is press cutting. However, the peel strength between the transparent resin film and the protective film is set small in order to prevent the adhesive residue from being left on the transparent resin film after the protective film is peeled off. Therefore, there is a problem that peeling occurs between the protective film and the transparent resin film due to deformation caused by cutting with a knife. Moreover, when cutting out and using a large area transparent resin film, there also exists a problem that manufacture of the Thomson blade (Thomson type|mold) for cutting out a large area transparent resin film is costly.

Therefore, the present inventors considered cutting a laminated film of a protective film and a transparent resin film with a laser. However, smear (residue of resin or the like) is generated at the interface between the protective film and the transparent resin film, which may cause peeling. In addition, the cut surface may be scorched, and the cross section may not be generally uniform.

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, the present invention provides the following favorable aspects.

[1] A laminate in which a transparent resin film and a protective film are laminated in this order,
The transparent resin film contains a resin and a solvent,
The resin is at least one selected from the group consisting of polyimide, polyamide and polyamideimide,
the solvent is N,N-dimethylacetamide;
The product (S × W) of the residual solvent amount S (% by mass) of the transparent resin film and the low molecular weight component amount W (%) of the protective film is 4.7 or less (W > 0.33, S ≤ 5) the laminate.
[2] The laminate according to [1], wherein the transparent resin film has a haze of 1.0% or less.
[3] The laminate according to [1] or [2], wherein the transparent resin film has a total light transmittance of 75% or more.
[4] The laminate according to any one of [1] to [3], wherein the protective film comprises a polyolefin-based or polyester-based resin film.

According to the present invention, it is possible to provide a laminate containing a transparent resin film based on a polyimide, polyamide, or polyamideimide-based polymer, which has good laser-cut quality and good appearance and visibility.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. It should be noted that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the gist of the present invention.

In the laminate of the present invention, a transparent resin film and a protective film are laminated in this order. Preferably, it is a laminate comprising a protective film bonded to at least one surface of the transparent resin film. The transparent resin film constituting the laminate of the present invention comprises at least one selected from the group consisting of polyimide, polyamide and polyamideimide, and at least one selected from the group consisting of polyimide, polyamide and polyamideimide. It is formed from a resin composition containing

As used herein, polyimide represents a polymer containing a repeating structural unit containing an imide group, and polyamideimide is a polymer containing both a repeating structural unit containing an imide group and a repeating structural unit containing an amide group. and polyamide represents a polymer containing repeating structural units containing amide groups. A polyimide-based polymer represents a polymer containing at least one selected from polyimide and polyamideimide.

Details of a polyimide resin film (also referred to as a polyimide film), which is an example of the transparent resin film, will be described below. In general, a polyimide resin film is prepared by applying a polyamic acid (polyimide precursor) solution obtained by reacting diamines and tetracarboxylic acids in a solvent to a support for producing a polyimide film and drying it to form a green film (hereinafter referred to as (also referred to as "polyamic acid film"), and further subjecting the green film to a high-temperature heat treatment on a polyimide film-producing support or in a state in which the green film is peeled off from the support to cause a dehydration ring-closing reaction.

Application of the polyamic acid (polyimide precursor) solution includes, for example, spin coating, doctor blade, applicator, comma coater, screen printing method, slit coating, reverse coating, dip coating, curtain coating, slit die coating, etc. Application of conventionally known solutions. means can be used as appropriate.

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 and laser cuttability, aromatic diamines are preferred. Diamines may be used alone or in combination of two or more.

The transparent polyimide film preferably has a total light transmittance of 75% or more. It is more preferably 80% or more, still more preferably 85% or more, even more preferably 87% or more, and particularly preferably 88% or more. Although the upper limit of the total light transmittance of the transparent polyimide film is not particularly limited, it is preferably 98% or less, more preferably 97% or less for use as a flexible electronic device. The transparent polyimide film in the present invention is preferably a polyimide film having a total light transmittance of 75% or more.

Aromatic tetracarboxylic acids for obtaining highly transparent polyimide films 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-dioxido-3,3-diyl)bis(benzene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4′-benzophenonetetracarboxylic acid, 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 acid anhydrides thereof. Among these, dianhydrides having two acid anhydride structures are preferred, particularly 4,4′-(2,2-hexafluoroisopropylidene)diphthalic dianhydride, 4,4′-oxydiphthalic Acid dianhydrides are preferred. Aromatic tetracarboxylic acids may be used alone, or two or more of them may be used in combination. The amount of aromatic tetracarboxylic acids to be copolymerized is, for example, preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass of the total tetracarboxylic acids when heat resistance is emphasized. More preferably, it is 80% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass.

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, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic 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-methano naphthalene-2,3,6,7-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetra Carboxylic 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 (aka "norbornane-2-spiro-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-cyclopenta Decanone-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, norbornane-2-spiro-α-(methylcyclohexanone)-α′-spiro-2″-norbornane-5,5′ tetracarboxylic acids such as ',6,6''-tetracarboxylic acid, and acid anhydrides thereof. Among these, dianhydrides having two acid anhydride structures are preferred, particularly 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclohexanetetracarboxylic acid Acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride is preferred, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic An acid dianhydride is more preferred, and 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride is even more preferred. In addition, these may be used independently and may use 2 or more types together. The amount of alicyclic tetracarboxylic acids to be copolymerized is, for example, preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass of the total tetracarboxylic acids when importance is placed on transparency. % or more, more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass.

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. acids or hydrogenated products of the above aromatic tricarboxylic acids such as hexahydrotrimellitic acid; Glycol bistrimellitate, and their monoanhydrides and esters. Among these, monoanhydrides having one acid anhydride structure are preferred, and trimellitic anhydride and hexahydrotrimellitic anhydride are particularly preferred. In addition, these may be used individually and may be used in combination.

Dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 4,4'-oxydibenzenecarboxylic acid, or the above aromatic dicarboxylic acids such as 1,6-cyclohexanedicarboxylic acid. Hydrogenates of oxalic acid, succinic acid, glutaric acid, adipic acid, heptanedioic acid, octanedioic acid, azelaic acid, sebacic acid, undecadeic acid, dodecanedioic acid, 2-methylsuccinic acid, and their acid chlorides Alternatively, an esterified product and the like can be mentioned. Among these, aromatic dicarboxylic acids and hydrogenated products thereof are preferred, and terephthalic acid, 1,6-cyclohexanedicarboxylic acid, and 4,4'-oxydibenzenecarboxylic acid are particularly preferred. In addition, dicarboxylic acids may be used alone or in combination.

Diamines or isocyanates for obtaining highly transparent polyimide films are not particularly limited, and polyimide synthesis, polyamideimide synthesis, aromatic diamines, aliphatic diamines, and alicyclic diamines commonly used in polyamide synthesis. , aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and the like can be used. From the viewpoint of heat resistance, aromatic diamines are preferred, and from the viewpoint of transparency, alicyclic diamines are preferred. In addition, the use of aromatic diamines having a benzoxazole structure makes it possible to exhibit high heat resistance, high elastic modulus, low thermal shrinkage, and low coefficient of linear expansion. Diamines and isocyanates may be used alone or in combination of two or more.

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-hexafluoro Propane, 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 '-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3,4 '-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, bis[4-(4-aminophenoxy)phenyl]methane, 1,1-bis[4-(4-aminophenoxy)phenyl]ethane, 1,2-bis [4-(4-aminophenoxy)phenyl]ethane, 1,1-bis[4-(4-aminophenoxy)phenyl]propane, 1,2-bis[4-(4-aminophenoxy)phenyl]propane, 1 ,3-bis[4-(4-aminophenoxy)phenyl]propane, 2,2 -bis[4-(4-aminophenoxy)phenyl]propane, 1,1-bis[4-(4-aminophenoxy)phenyl]butane, 1,3-bis[4-(4-aminophenoxy)phenyl]butane , 1,4-bis[4-(4-aminophenoxy)phenyl]butane, 2,2-bis[4-(4-aminophenoxy)phenyl]butane, 2,3-bis[4-(4-aminophenoxy) ) phenyl]butane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)-3-methylphenyl]propane, 2,2-bis[4-(4-amino phenoxy)-3-methylphenyl]propane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)-3,5-dimethylphenyl]propane, 2,2-bis [4-(4-aminophenoxy)-3,5-dimethylphenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoro Propane, 1,4-bis(3-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4- aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfoxide, bis[4 -(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 1,3-bis[4-(4- aminophenoxy)benzoyl]benzene, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 4,4'-bis[ (3-aminophenoxy)benzoyl]benzene, 1,1-bis[4-(3-aminophenoxy)phenyl]propane, 1,3-bis[4-(3-aminophenoxy)phenyl]propane, 3,4' -diaminodiphenyl sulfide, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, bis[4-(3-aminophenoxy)phenyl] methane, 1,1-bis[4-(3-aminophenoxy)phenyl]ethane, 1,2-bis Su[4-(3-aminophenoxy)phenyl]ethane, bis[4-(3-aminophenoxy)phenyl]sulfoxide, 4,4′-bis[3-(4-aminophenoxy)benzoyl]diphenyl ether, 4,4 '-bis[3-(3-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzophenone, 4,4'-bis[4- (4-amino-α,α-dimethylbenzyl)phenoxy]diphenylsulfone, bis[4-{4-(4-aminophenoxy)phenoxy}phenyl]sulfone, 1,4-bis[4-(4-aminophenoxy) Phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6 -trifluoromethylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-fluorophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[ 4-(4-amino-6-methylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-cyanophenoxy)-α,α-dimethylbenzyl]benzene, 3,3′-diamino-4,4′-diphenoxybenzophenone, 4,4′-diamino-5,5′-diphenoxybenzophenone, 3,4′-diamino-4,5′-diphenoxybenzophenone, 3, 3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzophenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3 '-diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino-5,5'-dibiphenoxybenzophenone, 3,4'-diamino-4,5'-dibiphenoxybenzophenone, 3,3'- diamino-4-biphenoxybenzophenone, 4,4'-diamino-5-biphenoxybenzophenone, 3,4'-diamino-4-biphenoxybenzophenone, 3,4'-diamino-5'-biphenoxybenzophenone, 1, 3-bis(3-amino-4-phenoxybenzoyl)benzene, 1,4-bis(3-amino-4-phenoxybenzoyl)benzene, 1,3-bis(4-amino-5-pheno xybenzoyl)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]benzonitrile, 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 and the like. In addition, some or all of the hydrogen atoms on the aromatic ring of the aromatic diamine may be substituted with a halogen atom, an alkyl or alkoxyl group having 1 to 3 carbon atoms, or a cyano group, and Some or all of the hydrogen atoms in the alkyl or alkoxyl groups of 1 to 3 may be substituted with halogen atoms. Further, 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, oxazole, 5-amino-2-(m-aminophenyl)benzoxazole, 6-amino-2-(m-aminophenyl)benzoxazole, 2,2′-p-phenylenebis(5-aminobenzoxazole), 2 , 2′-p-phenylenebis(6-aminobenzoxazole), 1-(5-aminobenzoxazolo)-4-(6-aminobenzoxazolo)benzene, 2,6-(4,4′-diamino diphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2,6-(4,4'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole , 2,6-(3,4′-diaminodiphenyl)benzo[1,2-d:5,4-d′]bisoxazole, 2,6-(3,4′-diaminodiphenyl)benzo[1,2 -d: 4,5-d']bisoxazole, 2,6-(3,3'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2,6-(3 ,3′-diaminodiphenyl)benzo[1,2-d:4,5-d′]bisoxazole and the like. Among these, 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 4-amino-N-(4-aminophenyl)benzamide, 4,4′-diaminodiphenylsulfone, 3,3 '-Diaminobenzophenone is preferred. Incidentally, the aromatic diamines may be used singly or in combination.

Alicyclic diamines include, for example, 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propyl cyclohexane, 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, 4,4'-methylenebis(2,6-dimethylcyclohexylamine) and the like. Among these, 1,4-diaminocyclohexane and 1,4-diamino-2-methylcyclohexane are particularly preferred, and 1,4-diaminocyclohexane is more preferred. Incidentally, the alicyclic diamines may be used alone or in combination.

Diisocyanates include, for example, 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'-diethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4, 3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-3, 3′-diisocyanate, diphenylmethane-3,4′-diisocyanate, diphenyl ether-4,4′-diisocyanate, benzophenone-4,4′-diisocyanate, diphenylsulfone-4,4′-diisocyanate, 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'-diethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4, Aromatic diisocyanates such as 4'-diisocyanate and 3,3'-diethoxybiphenyl-4,4'-diisocyanate, and diisocyanates obtained by hydrogenating any of these (e.g., isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate) and the like. Among them, 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. Diisocyanates may be used alone or in combination.

In this embodiment, the transparent resin film is preferably a polyimide film. When the transparent resin film is a polyimide film, it has excellent heat resistance. Moreover, when the transparent resin film is a polyimide film, it can be suitably cut with an ultraviolet laser.

The thickness of the transparent resin film is preferably 3 μm or more, more preferably 7 μm or more, still more preferably 14 μm or more, and still more preferably 20 μm or more. Although the upper limit of the thickness of the transparent resin film is not particularly limited, it is preferably 250 μm or less, more preferably 100 μm or less, and still more preferably 50 μm or less for use as a flexible electronic device.

The transparent resin film is preferably manufactured by a casting method.

When the transparent resin 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, and still more preferably 5 or less, and more preferably 3 or less. Although the lower limit of the yellowness index of the transparent polyimide is not particularly limited, it is preferably 0.1 or more, more preferably 0.2 or more, and still more preferably 0.3 or more for use as a flexible electronic device. is.

When the transparent resin film is a transparent polyimide film, the haze is preferably 1.0 or less, more preferably 0.8 or less, still more preferably 0.5 or less, and still more preferably 0.3 or less. . Although the lower limit is not particularly limited, industrially, there is no problem if it is 0.01 or more, and it may be 0.05 or more.

The transparent resin film is preferably obtained in the form of being wound up as a long polymer film with a width of 300 mm or more and a length of 10 m or more at the time of production. More preferably, it is in the form of a resin film. When the transparent resin film is wound into a roll, transportation in the form of the transparent resin film wound into a roll is facilitated.

In the transparent resin film, in order to ensure handleability and productivity, a lubricant (particles) having a particle diameter of about 10 to 1000 nm is added or contained in the transparent resin film in an amount of about 0.03 to 3% by mass. Therefore, it is preferable to provide the surface of the transparent resin film with fine irregularities to ensure slipperiness.

In the present invention, the lubricant includes inorganic particles such as silica particles, titanium particles, aluminum hydroxide, zirconia particles, barium titanate particles, and silicon compounds such as quaternary alkoxysilanes such as tetraethyl orthosilicate. From the viewpoint of the stability of the inorganic material and the dispersibility of the inorganic material, silica particles, aluminum hydroxide, and zirconia particles are preferred, and silica particles are more preferred.

The average primary particle size of the inorganic material is preferably 1 to 200 nm, more preferably 3 to 100 nm, even more preferably 5 to 50 nm, still more preferably 5 to 30 nm. When the average primary particle size is 100 nm or less, the transparency tends to be improved. When the average primary particle size is 10 nm or more, the cohesive force of the inorganic material is weakened, which tends to facilitate handling.

In the present invention, the silica particles may be a silica sol obtained by dispersing silica particles in an organic solvent or the like, or silica fine particle powder produced by a vapor phase method. A manufactured silica sol is preferred.

The average primary particle size of silica particles in the transparent resin film can be determined by observation with a transmission electron microscope (TEM). The particle size distribution of the silica particles before forming the transparent resin film can be obtained with a commercially available laser diffraction particle size distribution meter.

The resin composition forming the transparent resin film may further contain other components in addition to the components described above. Other ingredients include, for example, antioxidants, mold release agents, light stabilizers, bluing agents, flame retardants, and leveling agents.

As a solvent that can be used for preparing the resin varnish, a solvent capable of dissolving or dispersing a resin component such as a polyimide polymer can be appropriately selected. As the solvent, one type may be used alone, or two or more types may be used in combination. When two or more kinds of solvents are used, it is preferable to select the kinds of solvents so that the boiling point of the solvent having the highest boiling point among the solvents to be used falls within the above range. From the viewpoint of the solubility of the resin component, the coating property and the drying property, an organic solvent having a boiling point of 120 to 300°C is preferable, more preferably 120 to 270°C, still more preferably 120 to 250°C, and particularly preferably 120°C. Organic solvents with boiling points of ~230°C are preferred. Specific examples of such organic solvents include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; lactone solvents such as γ-butyrolactone and γ-valerolactone. ketone solvents such as cyclohexanone, cyclopentanone and methyl ethyl ketone; acetic acid ester solvents such as butyl acetate and amyl acetate; sulfur-containing solvents such as dimethylsulfone, dimethylsulfoxide and sulfolane, and carbonate solvents such as ethylene carbonate and propylene carbonate. etc. Among them, due to their excellent solubility in polyimide polymers and polyamides, N,N-dimethylacetamide (boiling point: 165°C), γ-butyrolactone (boiling point: 204°C), N-methylpyrrolidone (boiling point: 202°C), Solvents selected from the group consisting of cyclopentanone (boiling point: 131° C.), butyl acetate (boiling point: 126° C.) and amyl acetate (boiling point: 149° C.) are preferred.

In the present invention, since the transparent resin film contains N,N-dimethylacetamide, the solvent for preparing the resin varnish also preferably contains N,N-dimethylacetamide. In addition to containing N,N-dimethylacetamide, the other solvent may be mixed.

The amount of the solvent may be selected so that the viscosity of the resin varnish can be handled, and is not particularly limited. % by mass, more preferably 80 to 95% by mass.

Further, the content of the solvent in the transparent resin film constituting the laminate of the present invention is the residual solvent amount S (% by mass) calculated as the mass reduction rate at 120 ° C. to 250 ° C. by thermogravimetric-differential thermal measurement. , and the low-molecular-weight component content W (%) in the protective film, which will be described later, must be within a range that satisfies a predetermined relationship. In the present invention, the residual solvent amount S in the transparent resin film may be appropriately adjusted in relation to the low-molecular-weight component amount W in the protective film to be laminated, but is preferably 5% by mass or less, and more preferably. It is 3% by mass or less, more preferably 1% by mass or less. When the residual solvent amount S is equal to or less than the above upper limit, the resulting transparent resin film can be formed as a self-supporting film. In addition, the lower limit of the residual solvent amount S is not particularly limited, but in the production of a transparent resin film containing a polyimide polymer or polyamide as a resin component, the boiling point exceeding 100 ° C. as described above is generally Since a high boiling point solvent having From the viewpoint of flexibility, the content is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more. .

In the present invention, the residual solvent amount S is measured using a thermogravimetry-differential thermal (TG-DTA) measuring device, and the transparent resin film (sample) to be measured is heated from room temperature to 120 ° C. at 10 ° C./min. and held at 120°C for 5 minutes to remove adsorbed water, and then measured while increasing (heating) the temperature up to 400°C at a rate of 10°C/min. , the mass reduction rate S (% by mass) from 120° C. to 250° C. is calculated according to the relational expression (2).
S (% by mass) = 100 - (W1/W0) x 100 (2)
[In formula (2), W0 is the mass of the sample after being held at 120°C for 5 minutes, and W1 is the mass of the sample at 250°C measured by the thermogravimetric-differential calorimeter].

The amount of residual solvent S is determined by adjusting the amount of solvent contained in the resin varnish for forming the transparent resin film, the type of solvent, and the drying conditions (drying temperature and time, wind speed, etc.) of the coating film formed from the resin varnish. can be controlled.

The laminate of the present invention includes a protective film bonded to the transparent resin film. The protective film may be attached only to one surface of the transparent resin film, or may be attached to both surfaces. The protective film attached to the transparent resin film is usually a film for temporarily protecting the surface of the transparent resin film, and is not particularly limited as long as it is a peelable film that can protect the surface of the transparent resin film. , polyolefin resin films such as polyethylene and polypropylene films, or polyester resin films such as polyethylene terephthalate. When protective films are attached to both sides of the transparent resin film, the protective films on each side may be the same or different.

In the laminate of the present invention, the protective film is a base film and a pressure-sensitive adhesive layer laminated thereon, for example, an acrylic pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, or the like. or a self-adhesive resin film such as a polyolefin resin.

In addition, whitening of the transparent resin film, which is a problem of the present invention, is caused by elution of low-molecular-weight components contained in the protective film into the solvent used when producing the transparent resin film containing polyimide polymer and polyamide as resin components. It is thought that this is caused by In the present invention, as will be described later, the protective film preferably contains a low-molecular-weight component in order to obtain good laser cuttability. Therefore, it is preferable that the solvent amount S contained in the transparent resin film, which is another cause of whitening, be small. Specifically, it is preferably 5% by mass or less, more preferably 3% by mass or less.

Here, in the present invention, the "low-molecular weight component" contained in the protective film means that the Log M of the chart obtained by measuring by gel permeation chromatography at a measurement temperature of 140° C. is from 0 to 3.32 according to the following conditions. means a component detected in the range of

<Measurement conditions for gel permeation chromatography>
Column: One PLgel Individual (5 μm, 50 Å, 7.5 mm ID×30 cm, manufactured by Agilent Technologies) and two TSKgel GMHHR-H(S)HT (7.5 mm ID×30 cm, manufactured by Tosoh Corporation) are connected. Mobile phase: BHT (di-tert-butylhydroxytoluene) added to ortho-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd., special grade) at 0.1 w/v% flow rate: 1 mL/min Column oven temperature: 140°C
Autosampler temperature: 140°C
System oven temperature: 40°C
Detection: Differential Refractive Index Detector (RID)
RID cell temperature: 140°C
Sample solution injection volume: 300 μL
Standard substance solution for GPC column calibration: standard polystyrene manufactured by Tosoh Corporation More detailed measurement conditions for gel permeation chromatography are described in Examples described later.

Specifically, the low-molecular-weight components are residual monomers and oligomers contained in the protective film, or in the pressure-sensitive adhesive layer when the protective film consists of a base film and a pressure-sensitive adhesive layer laminated thereon. And it is considered to be a component derived from additives, film raw materials, and the like. Examples of low-molecular-weight components contained in protective films include nucleating agents, antioxidants, hydrochloric acid absorbers, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antiblocking agents, antistatic agents, flame retardants, and pigments. , Dyes, dispersants, copper damage inhibitors, neutralizers, foaming agents, plasticizers, antifoam agents, cross-linking agents, flow improvers such as peroxides, weld strength improvers, etc. Examples of low-molecular-weight components contained in the pressure-sensitive adhesive layer laminated on the film include components derived from tackifying resins, softening agents, and the like. Also, a small amount of organic solvent may be added to the pressure-sensitive adhesive layer in order to contain a large amount of low-molecular-weight components. In that case, select a solvent that does not dissolve the adhesive. Specifically, hexane or the like is suitable.

In the present invention, the content W of the low-molecular-weight components contained in the protective film is measured by gel permeation chromatography at a measurement temperature of 140° C. according to the measurement conditions of the above gel permeation chromatography. is defined as the ratio of the area from 0 to 3.32, the amount of low molecular weight component W (%) is in a range that satisfies a predetermined relationship in relation to the amount of residual solvent S (% by mass) in the transparent resin film described later. There must be. In the present invention, the amount W of low-molecular-weight components in the protective film may be appropriately adjusted in relation to the amount S of residual solvent in the transparent resin film to be laminated, but is preferably more than 0.33% and 0.35%. % is more preferred.

When the low-molecular-weight component content W is more than 0.33%, the quality of the laminate of the transparent resin film and the protective film obtained by laser cutting is good.
The inventors presume the reason for this as follows. When an ultraviolet laser is irradiated from the protective film side, the ultraviolet laser passes through the protective film base material (in the case of self-adhesive protective film, the protective film itself), but does not pass through the transparent resin, which is polyimide in this case. absorbs UV light and heats up locally. After that, the protective film substrate is perforated. That is, holes are formed in the direction of the substrate from the protective film/polyimide interface, which has reached a high temperature. At this time, if it takes a long time for the protective film substrate to be perforated completely, smears and gas generated by the ultraviolet laser irradiation enter between the protective film and the polyimide, resulting in poor quality. Specifically, smears adhere to the surface of the polyimide film, and the cut edges become black. When W is more than 0.33%, the decomposition of the protective film proceeds rapidly, and a large amount of outgassing occurs at the interface between the protective film and polyimide due to instantaneous heating with a laser, and the stress also affects the protective film substrate. perforate early. As described above, the protective film and the transparent resin film are suitably cut without being deformed or scorched. This is the same even when an ultraviolet absorber is added to a part of the protective film, since contamination and damage to the polyimide film can be suppressed if holes are formed in the substrate early.

Although the thickness of the protective film is not particularly limited, it is usually 10 μm or more, preferably 20 μm or more, and more preferably 25 μm or more from the viewpoint of protection of the transparent resin film. On the other hand, from the viewpoint of film handling, it is preferably 300 μm or less. When protective films are attached to both sides of the transparent resin film, the thickness of the protective films on each side may be the same or different.

In the present invention, the residual solvent amount S (% by mass) of the transparent resin film constituting the laminate and the low molecular weight component amount W (%) of the protective film bonded to the transparent resin film are expressed by the relational expression (1 ):
S × W ≤ 4.7 (1)
(However, W>0.33, S≤5)
A transparent resin film and a protective film are combined so as to satisfy Here, the residual solvent amount S (% by mass) of the transparent resin film is a value calculated as a mass reduction rate at 120 ° C. to 250 ° C. by thermogravimetric-differential thermal (TG-DTA) measurement, and the protective film The low-molecular-weight component content W (%) of the protective film is defined as the ratio of the area of Log M from 0 to 3.32 with respect to the total area of the chart measured by gel permeation chromatography at a measurement temperature of 140 ° C. is the value to be From the viewpoint of whitening suppression effect, the value of S×W (hereinafter also referred to as “the value of formula (1)”) in the laminate of the present invention is preferably 4.5 or less, more preferably 4.0. or less, more preferably 3.5 or less, even more preferably 3.4 or less, particularly preferably 3.3 or less, even more preferably 2.0 or less, particularly preferably 0 0.5 or less, particularly preferably 0.4 or less. When protective films are laminated on both sides of the transparent resin film, the relationship between the low-molecular-weight component content W of each protective film and the residual solvent content S of the transparent resin film satisfies the above formula (1). is preferred.

For the value of formula (1), when using a transparent resin film with a large amount of residual solvent, a protective film with a low low-molecular-weight component content is selected within the range satisfying W>0.33. When a large amount of protective film is used, it can be controlled by selecting a transparent resin film with a small amount of residual solvent.

By controlling the amount of residual solvent in the transparent resin film and the amount of low-molecular-weight components in the protective film, the laminate of the present invention has an excellent effect of suppressing whitening of the surface of the transparent resin film to which the protective film is laminated. Therefore, the transparent resin film constituting the laminate of the present invention is excellent in transparency, and its haze is preferably 1.0% or less, more preferably 0.7% or less, still more preferably 0.7% or less. 5% or less. Further, the total light transmittance of the transparent resin film constituting the laminate of the present invention is preferably 75% or more, more preferably 80% or more, still more preferably 85% or more, and still more preferably It is 87% or more, particularly preferably 88% or more. Furthermore, the yellowness of the transparent resin film constituting the laminate of the present invention is preferably 10.0 or less, more preferably 7.0 or less, still more preferably 5 or less, and still more preferably 3 or less. is. When the haze and total light transmittance of the transparent resin film constituting the laminate are within the above ranges, the laminate is suitable for optical applications requiring high transparency. In addition, the laminate of the present invention is suitable for optical applications because the yellowness of the transparent resin film is low and coloring is suppressed. It should be noted that the "whitening of the transparent resin film" in the present invention can be identified by irradiating a high-intensity light with a luminous flux of 3000 lumens, as will be described later in the examples. It does not necessarily directly affect the haze and total light transmittance of the resin film. The transparent resin film used by peeling off the protective film from the laminate of the present invention is less likely to cause whitening of the film surface and has excellent transparency. Compared with the case of using such a material, it becomes easier to ensure a constant brightness, and it becomes possible to suppress the emission intensity of a display element or the like. Therefore, power consumption can be reduced.

By controlling the amount of low-molecular-weight components in the protective film, the laminate of the present invention exhibits excellent quality when the protective film and the transparent resin film laminate are laser-cut. For this reason, smear is less likely to accumulate between the protective film and the transparent resin film, and it is possible to prevent smear from falling off during the protective film peeling process.

For example, when a transparent resin film is continuously produced by a method including a step of applying a resin varnish containing a solvent to form a film, followed by drying to remove the solvent, as typified by the casting method, the resin varnish is applied. The supporting base material to be used is a film-like base material, and may be, for example, a resin film base material or a steel base material (eg, SUS belt). Examples of resin film substrates include polyethylene terephthalate (PET) films. The thickness of the supporting substrate is not particularly limited, and is, for example, 10-500 μm, preferably 50-300 μm.

In the step of drying the coating film, it is preferable to remove the solvent by drying so that the solvent in the resin varnish is within the desired range. Drying to remove the solvent may be carried out by air drying, air drying, heat drying, vacuum drying, and combinations thereof. Heat drying is preferable from the viewpoint of production efficiency and the like. Drying conditions may be appropriately determined according to the type of solvent used, the content of the solvent in the film, etc., as long as the optical properties of the transparent resin film are not impaired. For example, it may be heated at a temperature of 50 to 450° C., preferably 70 to 430° C., for about 5 to 100 minutes.

Next, a protective film containing a low-molecular-weight component that satisfies the above formula (1) is attached to the transparent resin film to obtain a laminated film in which the protective film is laminated on the layer of the transparent resin film. A step of washing the surface of the transparent resin film, such as washing with water, may be included before bonding the transparent resin film and the protective film.

ADVANTAGE OF THE INVENTION The laminated body of this invention can suppress the whitening in the surface of the transparent resin film which laminated the protective film, and has high transparency and a favorable appearance. In addition, because of its excellent laser cutting quality, it can be suitably used for optical applications such as displays of various image display devices.

The present invention will be described in more detail below with reference to examples. Unless otherwise specified, "%" and "parts" in the examples are % by mass and parts by mass. The amount of residual solvent in the transparent resin film and the amount of low-molecular-weight components in the protective film used in Examples and Comparative Examples were measured and calculated according to the following methods.

<Method for measuring residual solvent amount S>
Thermogravimetric-Differential Thermal (TG-DTA) Measurement TG/DTA6300 manufactured by Hitachi High-Tech Science Co., Ltd. was used as a TG-DTA measuring device. About 20 mg of sample was obtained from the produced transparent polyimide film. This sample was heated from room temperature to 120° C. at a temperature increase rate of 10° C./minute, held at 120° C. for 5 minutes, and then heated (heated) to 400° C. at a temperature increase rate of 10° C./minute. , measured the mass change of the sample.

From the TG-DTA measurement results, the mass reduction rate S (mass%) from 120°C to 250°C was calculated according to the relational expression (2).
S (% by mass) = 100 - (W1/W0) x 100 (2)
[In formula (2), W0 is the mass of the sample after being held at 120°C for 5 minutes, and W1 is the mass of the sample at 250°C].
The calculated mass reduction rate S was defined as the residual solvent amount S (% by mass) in the transparent resin film.

<Method for measuring the amount of low-molecular-weight components>
The amount of low molecular weight components is determined by gel permeation chromatography (GPC) method. GPC measurement is performed under the following conditions. The amount of low molecular weight components is determined by gel permeation chromatography (GPC) method. For the obtained chromatogram, a chart was obtained by plotting the electric signal value (intensity Y) derived from the refractive index difference between the test solution and the reference solution against the polystyrene equivalent molecular weight Log M. For this chart, the line connecting the points with Log M of 0 and 7.61 was defined as the baseline. In addition, 0 was set for the portion where the intensity Y value corrected by the baseline was negative.
(1) Sample solution preparation conditions Solvent: BHT (di-tert-butylhydroxytoluene) was added to ortho-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd., special grade) at 0.1 w/v %.
Sample solution concentration: 1 mg/mL
Automatic shaker for dissolution: DF-8020 (manufactured by Tosoh Corporation)
Dissolution conditions: 5 mg of sample was enclosed in a 1000 mesh SUS wire mesh bag, the wire mesh bag containing the sample was placed in a test tube, and 5 mL of solvent was added to the test tube. Then, the test tube covered with aluminum foil was placed in the DF-8020 and stirred at 140° C. for 120 minutes at a stirring speed of 60 reciprocations/minute.

(2) Measurement conditions (GPC device and software)
Measuring device: HLC-8121 GPC/HT (manufactured by Tosoh Corporation)
Measurement software: GPC-8020 model II data collection Version 4.32 (manufactured by Tosoh Corporation)
Analysis software: GPC-8020 model II data analysis Version 4.32 (manufactured by Tosoh Corporation)
(Measurement condition)
GPC column: 1 PLgel Individual (5 μm, 50 Å, 7.5 mm ID × 30 cm, manufactured by Agilent Technologies) and 2 TSKgel GMHHR-H (S) HT (7.5 mm ID × 30 cm, manufactured by Tosoh Corporation) Connection Mobile phase: 0.1 w/V% BHT added to ortho-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd., special grade) Flow rate: 1 mL/min Column oven temperature: 140°C
Autosampler temperature: 140°C
System oven temperature: 40°C
Detection: Differential Refractive Index Detector (RID)
RID cell temperature: 140°C
Sample solution injection volume: 300 μL
GPC column calibration standard substance solution: Tosoh Corporation standard polystyrene was weighed as shown in the table below, added with 5 mL of ortho-dichlorobenzene (same composition as the mobile phase), and dissolved completely at room temperature. bottom.

From the GPC measurement results, the low molecular weight component content W (%) was calculated by the relational expression (3).
W (%) = V0/V1 (3)
[In formula (3), V0 is the area of the chart obtained from GPC measurement with Log M ranging from 0 to 3.32, and V1 is the area of the entire chart].

<Method for measuring elastic modulus>
The transparent resin films obtained in Examples and Comparative Examples were dried at 200° C. for 20 minutes and cut into strips of 10 mm×100 mm using a dumbbell cutter to obtain samples. The elastic modulus of this sample was measured using Autograph AG-IS manufactured by Shimadzu Corporation under the conditions of a chuck distance of 500 mm and a tensile speed of 20 mm/min to measure an SS curve, and the elastic modulus of the optical film was calculated from the slope. Calculated.

<Method for measuring total light transmittance>
The transparent resin films obtained in Examples and Comparative Examples were cut into a size of 30 mm×30 mm, and a haze computer (manufactured by Suga Test Instruments Co., Ltd., “HGM-2DP”) was used to analyze the optical film at a thickness of 50 μm. Total light transmittance (%) was measured.

<Method for measuring haze value>
The transparent resin films obtained in Examples and Comparative Examples were cut into a size of 30 mm×30 mm, and haze (%) was measured using a haze computer (manufactured by Suga Test Instruments Co., Ltd., "HGM-2DP"). .

<Method for measuring yellowness>
The transparent resin films obtained in Examples and Comparative Examples were cut into a size of 30 mm × 30 mm, and a tristimulus value ( X, Y, Z) were obtained and substituted into the calculation formula (4) to calculate the YI value.
YI=100×(1.2769X−1.0592Z)/Y (4)

<Synthesis Example 1: Preparation of transparent polyimide polymer>
A reactor comprising a separable flask equipped with a silica gel tube, a stirrer and a thermometer, and an oil bath were prepared. In this flask, 75.52 parts by mass of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ( TFMB) of 54.44 parts by mass was added. While stirring this at 400 rpm, 519.84 parts by mass of N,N-dimethylacetamide (DMAc) was added, and stirring was continued until the contents of the flask became a homogeneous solution. Subsequently, stirring was continued for an additional 20 hours while adjusting the temperature in the container to be in the range of 20 to 30° C. using an oil bath, and the mixture was reacted to produce polyamic acid. After 30 minutes, the stirring speed was changed to 100 rpm. After stirring for 20 hours, the temperature of the reaction system was returned to room temperature, and 649.8 parts by mass of DMAc was added to adjust the polymer concentration to 10% by weight. Further, 32.27 parts by mass of pyridine and 41.65 parts by mass of acetic anhydride were added, and imidization was performed by stirring at room temperature for 10 hours. The polyimide varnish was removed from the reaction vessel. The resulting polyimide varnish was dropped into methanol for reprecipitation, and the resulting powder was dried by heating to remove the solvent to obtain a transparent polyimide polymer as a solid content. GPC measurement of the resulting polyimide polymer revealed a weight average molecular weight of 360,000.

<Synthesis Example 2: Preparation of transparent polyamideimide polymer>
In a nitrogen gas atmosphere, 50 parts by mass (156.13 mmol) of TFMB and 642.07 parts by mass of DMAc were added to a 1 L separable flask equipped with a stirring blade, and TFMB was dissolved in DMAc with stirring at room temperature. Next, 20.84 parts by mass (46.91 mmol parts) of 6FDA was added to the flask and stirred at room temperature for 3 hours. After that, 9.23 parts by mass (31.27 mmol parts) of 4,4′-oxybis(benzoyl chloride) (OBBC) and then 15.87 parts by mass (78.18 mmol parts) of terephthaloyl chloride (TPC) were added to the flask. at room temperature for 1 hour. Next, 9.89 g (106.17 mmol) of 4-methylpyridine and 14.37 parts by mass (140.73 mmol) of acetic anhydride were added to the flask, stirred at room temperature for 30 minutes, and heated to 70°C using an oil bath. The temperature was raised and the mixture was further stirred for 3 hours to obtain a reaction solution.
The resulting reaction solution was cooled to room temperature and poured into a large amount of methanol in the form of a thread, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the precipitate was dried under reduced pressure at 100° C. to obtain a transparent polyamide-imide polymer. GPC measurement of the resulting polyamide-imide polymer revealed a weight average molecular weight of 420,000.

<Production Example 1: Production of transparent resin film A>
A resin varnish was obtained by dissolving the transparent polyimide polymer obtained in Synthesis Example 1 in a mixed solvent of GBL and DMAc at a ratio of 1:9 at a concentration of 16.5%. This resin varnish was applied to the non-slip surface of polyethylene terephthalate film A4100 (manufactured by Toyobo Co., Ltd.) using a comma coater so that the final film thickness would be 25 μm. The polyethylene terephthalate A4100 film was passed through a hot air oven and wound up, at which time it was dried at 100° C. for 10 minutes. After drying, the solvent-containing polyimide film that has obtained self-supporting properties is peeled off from the support, passed through a pin tenter having a pin sheet on which pins are arranged, and gripped by inserting the ends of the film into the pins, so as not to break the film. In addition, the pin sheet interval is adjusted so that unnecessary slack does not occur, and the sheet is conveyed, heated and dried under the conditions of 200°C for 3 minutes, 250°C for 3 minutes, 300°C for 3 minutes, and 330°C for 3 minutes. let me After that, the film was cooled to room temperature for 2 minutes, and portions of the film with poor flatness at both ends were cut off with a slitter and rolled up into a roll to obtain 200 m of polyimide film A with a width of 450 mm.

<Production Example 2: Production of transparent resin film B>
A resin varnish was obtained by dissolving the transparent polyimide polymer obtained in Synthesis Example 1 in DMAc at a concentration of 16.5%. This resin varnish was applied to the non-slip surface of polyethylene terephthalate film A4100 (manufactured by Toyobo Co., Ltd.) using a comma coater so that the final film thickness would be 25 μm. The polyethylene terephthalate A4100 film was passed through a hot air oven and wound up, at which time it was dried at 100° C. for 10 minutes. After drying, the solvent-containing polyimide film that has obtained self-supporting properties is peeled off from the support, passed through a pin tenter having a pin sheet on which pins are arranged, and gripped by inserting the ends of the film into the pins, so as not to break the film. In addition, the pin sheet interval is adjusted so that unnecessary slack does not occur, and the sheet is conveyed, heated and dried under the conditions of 200°C for 3 minutes, 250°C for 3 minutes, 280°C for 3 minutes, and 300°C for 3 minutes. let me After that, the film was cooled to room temperature for 2 minutes, and portions of the film with poor flatness at both ends were cut off with a slitter and rolled up into a roll to obtain 200 m of polyimide film B with a width of 450 mm.

<Production Example 3: Preparation of transparent resin film C>
A resin varnish was obtained by dissolving the transparent polyamide-imide polymer obtained in Synthesis Example 2 in DMAc at a concentration of 16.5%. 200 m of a polyamide-imide film C having a width of 450 mm was obtained in the same manner as in Production Example 1 except that this resin varnish was used.

<Production Example 4: Production of transparent resin film D>
A resin varnish was obtained by dissolving the transparent polyamide-imide polymer obtained in Synthesis Example 2 in DMAc at a concentration of 16.5%. 200 m of a polyamide-imide film D having a width of 450 mm was obtained in the same manner as in Production Example 2 except that this resin varnish was used.

<Production Example 5: Production of transparent resin film E>
A resin varnish was obtained by dissolving the transparent polyimide polymer obtained in Synthesis Example 1 in a mixed solvent of GBL and DMAc at a ratio of 1:9 at a concentration of 16.5%. This resin varnish was applied to the non-slip surface of polyethylene terephthalate film A4100 (manufactured by Toyobo Co., Ltd.) using a comma coater so that the final film thickness would be 25 μm. The polyethylene terephthalate A4100 film was passed through a hot air oven and wound up, at which time it was dried at 100° C. for 10 minutes. After drying, the solvent-containing polyimide film that has obtained self-supporting properties is peeled off from the support, passed through a pin tenter having a pin sheet on which pins are arranged, and gripped by inserting the ends of the film into the pins, so as not to break the film. In addition, the sheet was conveyed while adjusting the distance between the pin sheets so as not to cause unnecessary slack, and dried by heating under the conditions of 180° C. for 3 minutes and 200° C. for 4 minutes. After that, the film was cooled to room temperature for 2 minutes, and portions of the film having poor flatness at both ends were cut off with a slitter and rolled up into a roll to obtain 200 m of polyimide film E having a width of 450 mm.

<Preparing the protective film>
Commercially available protective films PF1 and PF3 were used.
PF1: Toretec 7832C (manufactured by Toray Advanced Film Co., Ltd.)
PF3: SUNYTECT SAT type (manufactured by Sanei Kaken Co., Ltd.)

Protective film PF2 was prepared as follows.

While stirring 100 parts by mass of urethane-based solvent-based adhesive US-902-50 (manufactured by Lion Specialty Chemicals, ethyl acetate solvent, solid content 50%), 5.4 mass of cross-linking agent N (manufactured by Lion Specialty Chemicals) were added and allowed to react at 40° C. for 20 minutes. After filtering the resulting solution with a PTFE cartridge filter (0.45 μm), 5 parts by mass of hexane was added, and after stirring, a base material (Toyobo Co., Ltd. A4100) and heated at 100° C. for 2 minutes to obtain a protective film.

A protective film was attached to the obtained transparent resin film using a roller to prepare a laminate. Table 2 shows the combinations and evaluation results.

<Appearance evaluation>
The appearance of the obtained transparent resin film was evaluated. The laminate was allowed to stand for 24 hours in an environment with a temperature of 23° C. and a humidity of 50%. After that, the laminated protective film was peeled off, and the surface of the transparent resin film to which the protective film was laminated was rubbed with a clean cloth. After that, using a high-intensity light with a luminous flux of 3,000 lumens, the appearance (whitening) of the film was evaluated according to the following evaluation criteria. Table 2 shows the results.

<Evaluation criteria for whitening>
○: Whitening was not confirmed ×: Whitening was confirmed on the surface of the transparent resin film

<Laser cutability evaluation>
The laminated film prepared above was irradiated with an ultraviolet laser from the protective film side so as to have a size of 70 mm×70 mm. The irradiation with the ultraviolet laser was performed without peeling off the protective film from the transparent resin film. The ultraviolet laser used is a pulsed laser with a wavelength of 355 nm manufactured by Takei Electric. The same place was scanned three times at a power of 8.5 W, a pulse frequency of 1000 kHz and a scanning speed of 500 mm/sec. As a result, the protective film and the transparent resin film were cut into a size of 70 mm×70 mm.

Here, the quality after the ultraviolet laser irradiation was confirmed. The protective film was peeled off from the laminate of the protective film and the transparent resin film, and the distance in the direction perpendicular to the laser-cut portion of the black powdery portion (smear) was determined, and the maximum value was taken as the smear width. Judgment was performed as follows.
◯: smear width of 500 μm or less ×: smear width of greater than 500 μm The results are shown in Table 2.

Claims (4)

A laminate in which a transparent resin film and a protective film are laminated in this order,
The transparent resin film contains a resin and a solvent,
The resin is at least one selected from the group consisting of polyimide, polyamide and polyamideimide,
the solvent is N,N-dimethylacetamide;
The product (S × W) of the residual solvent amount S (% by mass) of the transparent resin film and the low molecular weight component amount W (%) of the protective film is 4.7 or less (W > 0.33, S ≤ 5) the laminate. The laminate according to claim 1, wherein the transparent resin film has a haze of 1.0% or less. 3. The laminate according to claim 1, wherein the transparent resin film has a total light transmittance of 75% or more. The laminate according to any one of claims 1 to 3, wherein the protective film comprises a polyolefin-based or polyester-based resin film.