TW202000754A - Manufacturing method of transparent resin film using polyimide resin or polyamide resin material with good mechanical strength for obtaining a homogeneous transparent resin film - Google Patents

Abstract

The invention provides a method for manufacturing a transparent resin film, which is capable of obtaining a homogeneous transparent resin film. The method for producing a transparent resin film includes a step of respectively holding two ends of a long strip-shaped transparent resin film containing at least one resin selected from the group consisting of a polyimide resin and a polyamide resin; a step of transporting the held film; a step of setting the width of the held film to a specific distance (where the holding portion is not included in the distance), and heating the above resin film in a dryer; a step of setting the width of the resin film leaving the dryer (where the holding portion is not included in the width) to be 0.90 to 1.20 with respect to the width of the resin film before leaving the dryer (the holding portion is not included in the width); and a step of releasing the holding, in which a ratio of the relaxation (F) of a clamp to the width (W) of the film leaving the dryer (where the holding portion is not included in the width) satisfies 1.6 ≤ F/W×100 ≤ 7.0.

Description

Manufacturing method of transparent resin film

The invention relates to a method for manufacturing a transparent resin film.

In flexible display devices, a transparent resin film that replaces glass is required. As a material of such a transparent resin film, a material having transparency and mechanical strength such as polyimide-based resin or polyamide-based resin is known.

In the manufacture of such a transparent resin film, in order to obtain a desired quality, a heat treatment of the resin film may be performed (for example, refer to Patent Document 1).

However, if such a heat treatment is performed in, for example, a dryer, the film immediately after leaving the dryer is rapidly cooled to room temperature, so sometimes cracks or damages occur at the end of the film, so that the uniformity of the transparent resin film cannot be obtained . [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2010-36414

[Problems to be solved by the invention]

The present invention was made in view of such circumstances, and its object is to provide a method for manufacturing a transparent resin film that does not cause cracks or damages at the film end even if heat treatment is performed. [Technical means to solve the problem]

That is, the present invention provides the following. [1] A method for manufacturing a transparent resin film, which has The step of holding both ends of a long strip-shaped transparent resin film containing at least one resin selected from the group consisting of polyimide-based resins and polyamidide-based resins, Steps of transporting the held film, The step of setting the width of the film to be held at a specific distance (where the holding portion is not included in the distance) and heat-treating the resin film in a dryer, The width of the resin film leaving the dryer (where the holding portion is not included in the width) becomes 0.90 to 1.20 relative to the width of the resin film just before leaving the dryer (where the holding portion is not included in the width) step, And the steps to release holdings, In the step of releasing the holding, the ratio of the slack amount (F) of the jig to the width of the film leaving the dryer (where the holding portion is not included in the width) (W) satisfies 1.6≦F/W×100≦7.0 . [2] The manufacturing method according to [1], wherein the holding is performed by a plurality of jigs. [3] The manufacturing method according to [1] or [2], wherein the content of the organic solvent contained in the resin film after the heat treatment is 0.001 to 3% by mass relative to the mass of the resin film. [Effect of invention]

As described above, the present invention provides a method of manufacturing a transparent resin film that can obtain a transparent resin film that is free of cracks or damage at the film end.

The materials, dimensions, etc. exemplified in the following description are examples, and the present invention is not necessarily limited to these, and can be implemented with appropriate modifications without changing the scope of the gist thereof.

The present invention provides a method for manufacturing a transparent resin film, comprising: a long strip-shaped transparent resin film containing at least one resin selected from the group consisting of polyimide-based resins and polyamide-based resins The step of holding the two ends of each part, the step of transporting the film to be held, the width of the film to be held is set to a specific distance (where the holding part is not included in the distance), and the above resin film is heat-treated in the dryer The steps of making the width of the resin film leaving the dryer become 0.90~0.99 relative to the width of the resin film just before leaving the dryer (where the holding portion is not included in the width), and the step of releasing the holding.

[Polyimide-based resin, Polyamide-based resin] The transparent resin film of the present invention contains at least one resin selected from the group consisting of polyimide-based resins and polyamide-based resins. The polyimide-based resin refers to a polymer selected from the group consisting of a polymer containing a repeating structural unit containing an amide imide group (hereinafter, sometimes referred to as a polyimide), and a polymer containing an amide imide group and an amide group. At least one polymer in the group consisting of polymers of repeating structural units (hereinafter, sometimes referred to as polyamidoamide). In addition, the polyamide resin refers to a polymer containing a repeating structural unit containing an amide group.

The polyimide-based resin preferably has a repeating structural unit represented by formula (10). Here, G is a tetravalent organic group, and A is a divalent organic group. The polyimide-based resin may contain two or more types of repeating structural units represented by formula (10) in which G and/or A are different.

Polyimide-based resin may contain one selected from the group consisting of repeating structural units represented by formula (11), formula (12), and formula (13) within the range that does not impair the various physical properties of the transparent resin film the above.

In formula (10) and formula (11), G and G ¹ are each independently a tetravalent organic group, preferably an organic group that may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. As G and G ¹ , there can be exemplified: formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) or a group represented by formula (29) and a chain hydrocarbon group having a carbon number of 4 or less and a carbon number of 6 or less. In terms of easily suppressing the yellowness (YI value) of the transparent resin film, among them, formula (20), formula (21), formula (22), formula (23), formula (24), and formula ( 25), the base represented by formula (26) or formula (27).

In formula (20) to formula (29), * represents a bonding bond, and Z represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C( CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -Ar-, -SO ₂ -, -CO-, -O-Ar-O-, -Ar-O-Ar-, -Ar-CH _2- Ar-, -Ar-C(CH ₃ ) ₂ -Ar- or -Ar-SO ₂ -Ar-. Ar represents a C6-C20 arylene group which may be substituted with a fluorine atom. As a specific example, a phenylene group can be mentioned.

In formula (12), G ² is a trivalent organic group, preferably an organic group that may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. As G ² , there can be exemplified: formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) ) Or any one of the bonding bonds of the group represented by formula (29) is substituted with a hydrogen atom and a trivalent chain hydrocarbon group having a carbon number of 6 or less.

In formula (13), G ³ is a divalent organic group, preferably an organic group that may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. As G ³ , there can be exemplified: formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) ) Or the bonding bond of the group represented by formula (29), two groups that are not adjacent to each other and are substituted by hydrogen atoms and a chain hydrocarbon group having 6 or less carbon atoms.

In formula (10) to formula (13), A, A ¹ , A ² and A ³ are each independently a divalent organic group, preferably an organic group that may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. Examples of A, A ¹ , A ² and A ³ include formula (30), formula (31), formula (32), formula (33), formula (34), formula (35), formula (36), Groups represented by formula (37) or formula (38); those substituted with methyl, fluoro, chloro or trifluoromethyl; and chain hydrocarbon groups with a carbon number of 6 or less.

In formula (30) to formula (38), * represents a bonding bond, Z ¹ , Z ² and Z ³ independently represent a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH (CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or -CO-. An example is: Z ¹ and Z ³ are -O-, and Z ² is -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, or -SO ₂ -. The bonding positions of Z ¹ and Z ² to each ring, and the bonding positions of Z ² and Z ³ to each ring are preferably meta or para to each ring, respectively.

The polyimide-based resin preferably has at least the repeating structural unit represented by formula (10) and the repeating structural unit represented by formula (13) from the viewpoint of easily improving visibility. In addition, the polyamide resin preferably has at least a repeating structural unit represented by formula (13).

In one embodiment of the present invention, the polyimide-based resin system uses a diamine and a tetracarboxylic acid compound (a related compound of a tetracarboxylic acid compound such as an acetyl chloride compound and a tetracarboxylic dianhydride), and a dicarboxylic acid if necessary Condensed polymer obtained by reacting (polycondensing) acid compounds (dicarboxylic acid compounds such as acetyl chloride compounds) and tricarboxylic acid compounds (tricarboxylic acid compounds such as acetyl chloride compounds and tricarboxylic anhydrides), etc. The repeating structural unit represented by formula (10) or formula (11) is usually derived from a diamine and a tetracarboxylic acid compound. The repeating structural unit represented by formula (12) is usually derived from diamine and tricarboxylic acid compounds. The repeating structural unit represented by formula (13) is usually derived from a diamine and a dicarboxylic acid compound.

In one embodiment of the present invention, the polyamide resin is a condensation-type polymer obtained by reacting (condensing) a diamine and a dicarboxylic acid compound. That is, the repeating structural unit represented by formula (13) is usually derived from a diamine and a dicarboxylic acid compound.

Examples of the tetracarboxylic acid compound include aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic dianhydride; and aliphatic tetracarboxylic acid compounds such as aliphatic tetracarboxylic dianhydride. The tetracarboxylic acid compound may be used alone or in combination of two or more. In addition to the dianhydride, the tetracarboxylic acid compound may also be a tetracarboxylic acid compound related compound such as an acetyl chloride compound.

Specific examples of the aromatic tetracarboxylic dianhydride include: 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2 ,2',3,3'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 2,2',3,3'-biphenyl tetra Carboxylic dianhydride, 3,3',4,4'-diphenylene tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2 ,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl) propane dianhydride, 4,4'-(hexafluoroisopropylidene) di-o-benzene Dicarboxylic dianhydride (6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1, 2-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane Dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride and 4,4'-(p-phenylene dioxy) diphthalic dianhydride and 4,4'-(m-phenylene Dioxy) diphthalic dianhydride. These can be used alone or in combination of two or more.

Examples of the aliphatic tetracarboxylic dianhydride include cyclic or acyclic aliphatic tetracarboxylic dianhydride. The cycloaliphatic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure. Specific examples thereof include: 1,2,4,5-cyclohexanetetracarboxylic dianhydride, Cycloalkane tetracarboxylic dianhydride such as 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, bicyclo[2.2.2]octane- 7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride and positional isomers of these. These can be used alone or in combination of two or more. Specific examples of the non-cyclic aliphatic tetracarboxylic dianhydride include 1,2,3,4-butane tetracarboxylic dianhydride, 1,2,3,4-pentane tetracarboxylic dianhydride, etc. , These can be used alone or in combination of two or more. In addition, cyclic aliphatic tetracarboxylic dianhydride and non-cyclic aliphatic tetracarboxylic dianhydride can be used in combination.

Among the above-mentioned tetracarboxylic dianhydrides, from the viewpoint of high transparency and low colorability, 1,2,4,5-cyclohexanetetracarboxylic dianhydride and bicyclo[2.2.2]octan-7 are preferred -Ene-2,3,5,6-tetracarboxylic dianhydride and 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride, and mixtures thereof. In addition, as the tetracarboxylic acid, a water adduct of the acid anhydride of the above-mentioned tetracarboxylic acid compound can be used.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acids, aliphatic tricarboxylic acids, and related acetyl chloride compounds, acid anhydrides, and the like, and two or more kinds may be used in combination. Specific examples include: anhydride of 1,2,4-benzenetricarboxylic acid; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; a single bond between phthalic anhydride and benzoic acid,- A compound formed by connecting CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or phenylene.

Examples of the dicarboxylic acid compound include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and related acetyl chloride compounds, acid anhydrides, and the like, and two or more of them may be used in combination. As specific examples of these, terephthaloyl dichloride (terephthaloyl dichloride (TPC)); m-xylylene dichloride; naphthalene dichloromethane; 4,4'-linked Phthaloyl dichloride; 3,3'-biphenyl dimethyl dichloride; 4,4'-oxybis(benzoyl chloro) (OBBC); dicarboxylic acid of chain hydrocarbons with carbon number below 8 The compound and the two benzoic acids are connected by a single bond, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or phenylene.

Examples of diamines include aliphatic diamines, aromatic diamines, and mixtures of these. In addition, in this embodiment, the "aromatic diamine" refers to a diamine in which an amine group is directly bonded to an aromatic ring, and a part of its structure may contain an aliphatic group or other substituents. The aromatic ring may be a single ring or a condensed ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, and a stilbene ring, but are not limited thereto. Among these, the aromatic ring is preferably a benzene ring. The "aliphatic diamine" refers to a diamine in which an amine group is directly bonded to an aliphatic group, and a part of its structure may contain an aromatic ring or other substituents.

Examples of the aliphatic diamine include non-cyclic aliphatic diamines such as hexamethylene diamine, 1,3-bis(aminomethyl)cyclohexane, and 1,4-bis(aminomethyl)cyclohexane. Cyclic aliphatic diamines such as alkanes, norane diamines, 4,4'-diaminodicyclohexylmethane, etc. These can be used alone or in combination of two or more.

Examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, and 2 , 6-diaminonaphthalene and other aromatic diamines with one aromatic ring; 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'- Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenylbenzene, 3,4'-diamine Diphenyl benzene, 3,3'-diaminodiphenyl benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4 ,4'-diaminodiphenyl sulfone, bis[4-(4-aminophenoxy)phenyl] phenanthrene, bis[4-(3-aminophenoxy)phenyl] phenanthrene, 2,2 -Bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethyl Aniline, 2,2'-bis(trifluoromethyl) benzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 4,4'-bis (4-aminophenoxy) biphenyl, 9,9-bis(4-aminophenyl) stilbene, 9,9-bis(4-amino-3-methylphenyl) stilbene, 9,9 -Bis(4-amino-3-chlorophenyl) stilbene, 9,9-bis(4-amino-3-fluorophenyl) stilbene and other aromatic diamines having two or more aromatic rings. These can be used alone or in combination of two or more.

Among the above diamines, from the viewpoint of high transparency and low colorability, it is preferable to use one or more selected from the group consisting of aromatic diamines having a biphenyl structure, and it is more preferable to use one selected from the group consisting of 2 ,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-bis(4-aminophenoxy)biphenyl and 4,4'-diamine More than one of the group consisting of diphenyl ether is further preferably 2,2'-bis(trifluoromethyl)benzidine.

The polyimide-based resin is obtained by mixing the above raw materials such as the diamine, the tetracarboxylic acid compound, the tricarboxylic acid compound, and the dicarboxylic acid compound by conventional methods such as stirring, etc. The resulting intermediate is subjected to imidization in the presence of an imidization catalyst and optionally a dehydrating agent. The polyamide resin is obtained by mixing the raw materials such as the above-mentioned diamine and dicarboxylic acid compound by a conventional method such as stirring.

The imidate catalyst used in the imidate step is not particularly limited, and examples thereof include aliphatic amines such as tripropylamine, dibutylpropylamine, and ethyldibutylamine; N -Alicyclic amines (monocyclic) such as ethyl piperidine, N-propyl piperidine, N-butyl pyrrolidine, N-butyl piperidine, and N-propyl hexahydropyrazine; azabicyclo[ 2.2.1] Heptane, azabicyclo[3.2.1]octane, azabicyclo[2.2.2]octane and azabicyclo[3.2.2]nonane and other alicyclic amines (polycyclic); And 2-picoline, 3-picoline, 4-picoline, 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, 2,4-lutidine, 2,4, Aromatic amines such as 6-trimethylpyridine, 3,4-cyclopentenopyridine, 5,6,7,8-tetrahydroisoquinoline and isoquinoline.

The dehydrating agent used in the amide imidization step is not particularly limited, and examples thereof include acetic anhydride, propionic anhydride, isobutyric anhydride, trimethylacetic anhydride, butyric anhydride, and isovaleric anhydride.

In the mixing and imidization steps of the raw materials, the reaction temperature is not particularly limited, for example, 15 to 350°C, preferably 20 to 100°C. The reaction time is not particularly limited, for example, it is about 10 minutes to 10 hours. If necessary, the reaction can be carried out under an inert environment or under reduced pressure. In addition, the reaction can be carried out in a solvent, and examples of the solvent include, for example, the solvent used in the preparation of varnish. After the reaction, the polyimide resin or the polyimide resin is refined. Examples of the purification method include a method such as adding a poor solvent to the reaction solution, depositing the resin by the reprecipitation method, drying and taking out the precipitate, and washing and drying the precipitate with a solvent such as methanol as necessary. In addition, for the production of the polyimide-based resin, for example, the production method described in Japanese Patent Laid-Open No. 2006-199945 or Japanese Patent Laid-Open No. 2008-163107 can be referred to. In addition, commercially available products may be used for the polyimide-based resin. Specific examples thereof include Neopulim (registered trademark) manufactured by Mitsubishi Gas Chemical Co., Ltd., and KPI-MX300F manufactured by Kawamura Industries (Co., Ltd.).

The weight average molecular weight of the polyimide-based resin or the polyamidoamine-based resin is preferably 200,000 or more, more preferably 250,000 or more, and further preferably 300,000 or more, preferably 600,000 or less, and more preferably 500,000 or less. The greater the weight-average molecular weight of the polyimide-based resin or the polyamide-based resin, the greater the tendency to exhibit higher flex resistance during film formation. Therefore, from the viewpoint of improving the flex resistance of the transparent resin film, the weight average molecular weight is preferably at least the above lower limit. On the other hand, the smaller the weight average molecular weight of the polyimide-based resin or the polyamide-based resin, the easier it is to lower the viscosity of the varnish and to improve the processability. In addition, there is a tendency to easily improve the extensibility of the polyimide-based resin or the polyamide-based resin. Therefore, from the viewpoint of processability and extensibility, the weight average molecular weight is preferably equal to or less than the above upper limit. In addition, in this case, the weight average molecular weight can be measured by gel permeation chromatography (GPC), and can be calculated by standard polystyrene conversion, for example, by the method described in the examples.

The imidate ratio of the polyimide-based resin is preferably 95 to 100%, more preferably 97 to 100%, further preferably 98 to 100%, and still more preferably 100%. From the viewpoint of the stability of the varnish and the mechanical properties of the obtained transparent resin film, the imidate ratio is preferably at least the above lower limit. Furthermore, the imidate ratio can be obtained by IR method, NMR (nuclear magnetic resonance, nuclear magnetic resonance) method, or the like. From the above viewpoint, the polyimide-based resin contained in the varnish preferably has an imidization ratio within the above range. The aforementioned imidate ratio can be obtained by, for example, the method described in Japanese Patent Application No. 2018-007523.

In a preferred embodiment of the present invention, the polyimide-based resin or the polyamide-based resin contained in the transparent resin film of the present invention may contain, for example, fluorine atoms introduced by the above-mentioned fluorine-containing substituents, etc. Etc. halogen atoms. When the polyimide-based resin or the polyamide-based resin contains halogen atoms, it is easy to increase the elastic modulus of the transparent resin film and reduce the yellowness (YI value). If the elastic modulus of the transparent resin film is high, it is easy to suppress the occurrence of damage and wrinkles of the film, and if the yellowness of the transparent resin film is low, it is easy to improve the transparency of the film. The halogen atom is preferably a fluorine atom. Examples of preferred fluorine-containing substituents for containing a fluorine atom in the polyimide-based resin or polyamidoamine-based resin include a fluorine group and a trifluoromethyl group.

The content of halogen atoms in the polyimide resin or polyimide resin is based on the mass of the polyimide resin or polyimide resin, preferably 1 to 40% by mass, more preferably 5 to 40% by mass, more preferably 5 to 30% by mass. If the content of halogen atoms is 1% by mass or more, it is easy to further increase the elastic modulus at the time of film formation, reduce the water absorption rate, further reduce the yellowness (YI value), and further improve the transparency. In addition, if the content of halogen atoms is 40% by mass or less, synthesis may be easy.

In one embodiment of the present invention, the content of the polyimide-based resin and/or the polyamidoamine-based resin in the transparent resin film is preferably 40% by mass or more based on the total mass of the transparent resin film. It is more preferably 50% by mass or more, and further preferably 70% by mass or more. From the viewpoint of easy improvement of flex resistance and the like, the content of the polyimide-based resin and/or the polyamide-based resin is preferably at least the above lower limit. In addition, the content of the polyimide-based resin and/or the polyamide-based resin in the transparent resin film is generally 100% by mass or less based on the total mass of the transparent resin film.

[additive] The transparent resin film of the present invention may further contain additives such as fillers. Examples of such additives include silicon dioxide particles, ultraviolet absorbers, whitening agents, silicon dioxide dispersants, antioxidants, pH adjusters, and leveling agents.

(Silica particles) The transparent resin film of the present invention may further contain silica particles as an additive. The content of silicon dioxide particles is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and more preferably 5 parts by mass or more, preferably 60 parts by mass or less, relative to 100 parts by mass of the transparent resin film. It is preferably 50 parts by mass or less, and more preferably 45 parts by mass or less. In addition, the content of silicon dioxide particles can be any combination of the lower limit and the upper limit among the upper limit and the lower limit. If the content of silicon dioxide particles is within the numerical range of the upper limit and/or the lower limit, there is a tendency for the silicon dioxide particles to be hardly aggregated and uniformly dispersed in the state of primary particles in the transparent resin film of the present invention. Therefore, the decrease in visibility of the transparent resin film of the present invention can be suppressed.

The particle diameter of the silicon dioxide particles is preferably 1 nm or more, more preferably 3 nm or more, further preferably 5 nm or more, still more preferably 8 nm or more, preferably 30 nm or less, more preferably 28 nm or less It is further preferably 25 nm or less, and still more preferably 20 nm or less. The particle size of the silica particles can be any combination of the lower limit and the upper limit among the upper limit and the lower limit. If the content of silicon dioxide particles is within the numerical range of the upper limit and/or the lower limit, the transparent resin film of the present invention is less likely to interact with light of a specific wavelength in white light, so the present invention can be suppressed The visibility of the transparent resin film decreases. In this specification, the particle size of silica particles means the average primary particle size. The particle size of the silicon dioxide particles in the transparent resin film can be measured from a camera using a transmission electron microscope (TEM). The particle size of the silica particles before the transparent resin film is made (for example, before being added to the varnish) can be measured by a laser diffraction particle size distribution meter.

Examples of the form of the silica particles include silica sol in which silica particles are dispersed in an organic solvent and the like, and silica powder prepared by a vapor phase method. Among these, from the viewpoint of workability, silica sol is preferred.

The silicon dioxide particles may be subjected to surface treatment. For example, the silicon dioxide particles may be replaced with a solvent (more specifically, γ-butyrolactone, etc.) from a water-soluble alcohol-dispersed silica sol. The water-soluble alcohol is an alcohol having a carbon number of 3 or less per hydroxyl group in one molecule of the water-soluble alcohol, and examples thereof include methanol, ethanol, 1-propanol, and 2-propanol. Generally, if the silica particles are surface-treated, the compatibility with the polyimide-based polymer contained in the transparent resin film increases, and the dispersibility of the silica particles tends to increase, so the present invention can be suppressed. The visibility declines, but it also depends on the affinity of the silica particles and the type of polyimide-based polymer.

(UV absorber) The transparent resin film of the present invention may further contain an ultraviolet absorber. For example, three types of ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, etc. can be cited. These can be used alone or in combination of two or more. Preferred commercially available ultraviolet absorbers include, for example, Sumika Chemtex (registered trademark) Sumisorb (registered trademark) 340, ADEKA (registered trademark) Adekastab (registered trademark) LA-31, and BASF JAPAN (shared) The TINUVIN (registered trademark) 1577 and so on. The content of the ultraviolet absorber is preferably 1 phr or more and 10 phr or less, more preferably 3 phr or more and 6 phr or less, based on the mass of the transparent resin film of the present invention.

(Brightener) The transparent resin film of the present invention may further contain a whitening agent. The whitening agent can be added for the purpose of adjusting the color tone when, for example, an additive other than the whitening agent is added. Examples of the whitening agent include monoazo dyes, triarylmethane dyes, phthalocyanine dyes, and anthraquinone dyes. Among these, anthraquinone-based dyes are preferred. Examples of preferred commercially available whitening agents include MACROLEX (registered trademark) Violet B manufactured by Lanxess, Sumiplast (registered trademark) Violet B manufactured by Sumika Chemtex (share), and Diaresin manufactured by Mitsubishi Chemical (share) (Registered trademark) Blue G, etc. These can be used alone or in combination of two or more. When the whitening agent is included, the content is based on the mass of the transparent resin film of the present invention, preferably 1 to 50 ppm, more preferably 1 to 45 ppm, further preferably 3 to 40 ppm, and more Preferably it is 5~35 ppm.

The application of the transparent resin film of the present invention is not particularly limited, and can be used for various applications. As described above, the transparent resin film may be a single layer or a laminate. The transparent resin film may be used as it is, or it may be further used as a laminate with other films. Since this transparent resin film has excellent surface quality, it is useful as a transparent resin film in an image display device or the like.

The transparent resin film of the present invention is useful as a front panel of an image display device, especially a front panel (window film) of a flexible display. The flexible display includes, for example, a flexible functional layer and the above-mentioned polyimide-based film that overlaps the flexible functional layer and functions as a front panel. That is, the front panel of the flexible display is disposed on the viewing side above the flexible functional layer. The front panel has the function of protecting the flexible functional layer.

[Manufacturing method of transparent resin film] The transparent resin film of the present invention is not particularly limited, for example, it can be manufactured by a method including the following steps: (a) a step of preparing a liquid (hereinafter sometimes referred to as varnish) containing the above resin and the above filler (varnish preparation step), (b) The step of applying the varnish to the substrate to form a coating film (coating step), and (c) The step of drying the applied liquid (coating film) to form a transparent resin film (transparent resin film forming step).

In the varnish preparation step, the above resin is dissolved in a solvent, the above filler and other additives as needed are added and mixed with stirring, thereby preparing a varnish. Furthermore, in the case of using silica as a filler, the above-mentioned resin-soluble solvent, such as the solvent used in the preparation of the following varnish, can be replaced by a dispersion of silica-containing silica sol Silica sol is added to the resin.

The solvent used in the preparation of the varnish is not particularly limited as long as it can dissolve the above resin. Examples of the solvent include: amide-based solvents such as N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide (DMF); γ-butyrolactone (GBL), Lactone-based solvents such as γ-valerolactone; sulfur-based solvents such as dimethyl ash, dimethyl sulfoxide, and ciprool; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and the like combination. Among these, an amide-based solvent or a lactone-based solvent is preferred. These solvents can be used alone or in combination of two or more. In addition, the varnish may contain water, alcohol solvents, ketone solvents, acyclic ester solvents, ether solvents, and the like. The solid content concentration of the varnish is preferably 1 to 25% by mass, more preferably 5 to 20% by mass. The solid content can be measured by the drying method.

In the coating step, the varnish is coated on the substrate by a known coating method to form a coating film. Known coating methods include, for example, roll coating methods such as wire bar coating, reverse coating, and gravure coating, die coating methods, comma coating methods, and die lip coating methods. , Screen coating method, spray coating method, spray method, casting method, etc.

In the step of forming a transparent resin film, the coating film is dried and peeled from the substrate, whereby a long strip-shaped transparent resin film can be formed. After peeling, a heat treatment step of drying the transparent resin film may be further performed. The heat treatment of the coating film can usually be carried out at a temperature of 50~350℃. If necessary, the coating film can be dried under an inert environment or under reduced pressure. In the heat treatment, the two ends of the long strip-shaped transparent resin film are respectively held, and the film is held on one side, and the width of the film held on the other side is set to a specific distance, for example, while being transported in a dryer, the heat treatment is performed . At this time, the ratio of the width of the film after heat treatment (where the holding portion is not included in the width) to the width of the film before heat treatment (where the holding portion is not included in the width) becomes 1.1 or less, and the The resin film left by the dryer is held so that the transparent resin film can be heat-treated. The ratio of the width of the film after heat treatment (where the holding portion is not included in the width) to the width of the film before heat treatment (where the holding portion is not included in the width) (hereinafter, sometimes referred to as stretch ratio) is better It is 0.70 to 1.10, more preferably 0.8 to 1.05, and further preferably 0.80 to 1.00. The holding of the film can be performed by using a plurality of jigs, for example. In addition, since the holding portion is held by a jig or the like, it cannot be the above-mentioned stretchable width, so when calculating the stretch magnification, it is described as being removed from the film width. The plurality of jigs can be fixed to a loop chain of a specific length according to the size of the conveying device. The chain moves at the same speed as the film. A jig is provided at an appropriate position on the chain. The transparent resin film is placed before entering the dryer. Hold, release the hold when leaving the dryer. As a plurality of jigs provided at one end of the film, the space between adjacent jigs is set to, for example, 1 to 50 mm, preferably 3 to 25 mm, and more preferably 5 to 10 mmm. Also, it can be set as follows: when the straight line orthogonal to the film transport axis is aligned with the center of the holding portion of any jig at one end of the film, the intersection point of the straight line with the other end of the film and the holding portion of the jig closest to the intersection point The distance between the centers is preferably 3 mm or less, more preferably 2 mm or less, and further preferably 1 mm or less. By making the distance within the above range, the optical properties such as the phase difference between the left and right of the film can be made uniform. If the ratio of the width of the film after heat treatment to the width of the film before heat treatment is within the above range, the appearance of the film tends to be good. The amount of solvent in the film after heat treatment is based on the quality of the film, preferably 0.001 to 3% by mass, more preferably 0.001 to 2% by mass, further preferably 0.001 to 1.5% by mass, even more preferably 0.001 to 1.3 quality%. If the amount of solvent in the film after the heat treatment is within the above range, the appearance of the film tends to be good. If the heat treatment is over and the film leaves the dryer, the film's retention is released, preferably the film ends are torn off immediately. By tearing off the end of the film, the rupture in the end of the film that is easy to be generated between the holding part and the unheld part is removed from the film, thereby preventing the film from being transported and the temperature from dropping due to the subsequent The expansion of the resulting film rupture.

If the film leaves the dryer, the film is rapidly cooled and shrunk, sometimes breaking. Therefore, it is preferable to have a step of relaxing a certain percentage of the film from the outlet of the dryer to the position where the film holding is released. As this ratio, the comparison between the width of the film leaving the dryer (where the retention width is removed) (W) and the distance (F) from the dryer exit to the release of the film until the film is released is preferably 1.7≦F/ W×100≦6.9, more preferably 1.8≦F/W×100≦6.8, further preferably 1.9≦F/W×100≦6.7, and even more preferably 2.0≦F/W×100≦6.7. The slack distance on one end side is set to Fa, and the slack distance on the other end side is set to Fb with respect to the transport direction of the film. The distance from the outlet of the dryer to the time when the holding of the film is released is preferably 200 to 2,000 mm, more preferably 300 to 1,500 mm, further preferably 300 to 1,300 mm, and still more preferably 300 to 1,000 mm. If the distance is within the above range, there is a tendency that the film is less likely to be cracked, and poor appearance such as sagging is less likely to occur.

As an example of the base material, if it is a metal system, it may include: SUS (Steel Use Stainless, Japanese stainless steel standard) endless belt, if it is a resin system, it may include: a long strip of PET (polyethylene terephthalate, poly Ethylene terephthalate) film, PEN (polyethylene naphthalate, polyethylene naphthalate) film, other polyimide resin or polyimide resin film, cycloolefin polymer (COP) film, Acrylic film, etc. Among them, from the viewpoint of excellent smoothness and heat resistance, PET films, COP films, and the like are preferable, and further, from the viewpoint of adhesion to a transparent resin film and cost, PET films are more preferable.

Protective film In the present invention, the transparent resin film may include a protective film bonded to the transparent resin film to form a laminate. The protective film is attached to the unsupported surface of the transparent resin film. When the laminated body is wound in a roll shape, when there is a problem such as sticking, the protective film may be additionally attached to the surface of the support opposite to the transparent resin film on the basis of the above. The protective film attached to the transparent resin film is a film for temporarily protecting the surface of the transparent resin film, and it is not particularly limited as long as it can protect the surface of the transparent resin film and can be peeled off. For example, polyester resin films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin resin films such as polyethylene and polypropylene films; The acrylic resin film and the like are preferably selected from the group consisting of polyolefin resin film, polyethylene terephthalate resin film and acrylic resin film. When the protective film is attached to both sides of the laminate, the protective films on each side may be the same or different.

The thickness of the protective film is not particularly limited, but it is usually 10 to 100 μm, preferably 10 to 80 μm. When the protective film is attached to both sides of the laminate, the thickness of the protective film on each side may be the same or different.

Laminated film roll In the present invention, the layered product (support, transparent resin film, and optional protective film) wound around the core in a roll is called a layered film roll. In the continuous production of laminated film rolls, due to other constraints of space, it is often stored temporarily in the form of a film roll, and the laminated film roll is also one of them. If it is in the form of a laminate film roll, the laminate is wound more tightly, so the substance causing the cloudiness on the support is easily transferred to the transparent resin film. However, if the support body of the present invention having a specific contact angle to water is used, it is difficult for the white turbid substance from the support body to be transferred to the transparent resin film, and even if it is wound around the laminate film roll, it is difficult to produce white turbidity.

Examples of the material constituting the core of the laminate film roll include polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyester resin, epoxy resin, phenol resin, melamine resin, silicone resin, and polyamine group. Formate resin, polycarbonate resin, ABS (acrylonitrile-butadiene-styrene resin) resin and other synthetic resins; aluminum and other metals; fiber reinforced plastic (FRP (fiber reinforced plastice): Composite materials that contain fibers such as glass fibers in plastic to increase strength) etc. The winding core is formed into a cylindrical shape or a cylindrical shape, and the diameter thereof is, for example, 80 to 170 mm. In addition, the diameter of the film roll (diameter after winding) is not particularly limited, but is usually 200 to 800 mm.

Furthermore, after the protective film is attached to the transparent resin film, it can be torn to a desired width. [Example]

Hereinafter, the effects of the present invention will be further clarified by examples. In addition, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications without changing the gist of the invention.

(Weight average molecular weight) Gel permeation chromatography (GPC) determination (1) Pre-processing method After dissolving the sample in γ-butyrolactone (GBL) to make a 20% by mass solution, it was diluted to 100 times with a DMF eluent, and a filter using a 0.45 μm membrane filter was used as the measurement solution. (2) Measurement conditions Column: TSKgel SuperAWM-H×2+SuperAW2500×1 (6.0 mm I.D.×150 mm×3 pieces) Dissolution solution: DMF (addition of 10 mmol/L lithium bromide) Flow rate: 0.6 mL/min Detector: RI detector Column temperature: 40℃ Injection volume: 20 μL Molecular weight standard: standard polystyrene

＜Determination of Amidation Rate＞ The polyimide resin and the polyimide amide imide resin used in the examples and comparative examples were measured for their imilation rate by NMR, using a signal derived from the partial structure represented by formula (Chem XXX) And figure it out. The measurement conditions and the method of calculating the imidate ratio from the obtained results are as follows.

(Measurement conditions of NMR) Measuring device: 600 MHz NMR device AVANCE600 manufactured by Bruker Sample temperature: 303 K Measuring method: ¹ H-NMR, HSQC (heteronuclear singular quantum correlation, heteronuclear single quantum coherence)

(Calculation method of polyimide resin's imidization ratio) The ¹ H-NMR spectrum obtained by using a solution containing polyimide resin as a measurement sample is derived from protons in formula (XXX) ( The integral value of the signal of A) is set to Int _A , and the integral value of the signal from the proton (B) is set to Int _B. From these values, the imidate ratio (%) was determined by the following formula (NMR-1).

Acetylimidization rate (%)=100×(1-Int _B /Int _A ) (NMR-1)

<Measurement of total light transmittance (Tt)> The total light transmittance of the transparent resin film is measured in accordance with JIS K 7105:1981 by a fully automatic direct-read haze computer HGM-2DP manufactured by Suga Test Instruments. The results are shown in Table 3.

<Measurement of haze> The haze of the transparent resin film was measured in accordance with JIS K 7105: 1981 by a fully automatic direct-read haze computer HGM-2DP manufactured by Suga Test Instruments Co., Ltd. The results are shown in Table 3.

<Measurement of Yellowness (YI)> The yellow index (yellowness: YI value) of the transparent resin film was measured by an ultraviolet visible near infrared spectrophotometer V-670 manufactured by Japan Spectroscopy Corporation. After background measurement without a sample, a transparent resin film is set in the sample holder, and the transmittance of light of 300 to 800 nm is measured to obtain tristimulus values (X, Y, Z). The YI value is calculated based on the following formula. YI value=100×(1.2769X-1.0592Z)/Y The results are shown in Table 3.

<Measurement of residual solvent amount> Using TG-DTA (EXSTAR6000 TG/DTA6300 manufactured by SII), the transparent resin films obtained in Examples 1 and 2 and Comparative Examples and 2 were heated from 30°C to 120°C, and kept at 120°C for 5 minutes. Thereafter, the temperature was raised to 400°C at a temperature increase rate of 5°C/min. The ratio of the decrease in the mass of the film from 120°C to 250°C relative to the mass of the film at 120°C was calculated as the solvent content in the film (referred to as the residual solvent amount). The results are shown in Table 3.

<Cracked> At the position where the film is unfastened from the jig, visually confirm the film during 50 m of the film and check for cracks. The results are shown in Table 2.

<Scratch> The surface of the obtained film was irradiated with a Prairie lamp ["PS-X1" manufactured by Polarion Corporation] (3,400 lumens) in the direction of self-advancement (ie, longitudinal direction). At this time, the film is irradiated at an angle of about 20 to 70° relative to the film surface. The direction of visual recognition is: from directly above the surface of the evaluated resin film (at an angle of 90° with respect to the surface of the resin film), visually check for scratches. In Table 2, the case without scratches was rated as good and indicated as, and the case with scratches was rated as poor and indicated as ×.

<Production Example 1: Polyimide resin (2) production) Under a nitrogen atmosphere, add 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB) 45 g (140.52 mmol) to a 1 L separable flask equipped with a stirring blade And 768.55 g of N,N-dimethylacetamide (DMAc), dissolving TFMB in DMAc while stirring at room temperature. Next, 18.4 g (42.58 mmol) of 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride (6FDA) was added to the flask, and stirred at room temperature for 3 hours. Thereafter, 4.4'-oxybis(benzyl chloride) (OBBC) 4.19 g (14.19 mmol) was added to the flask, followed by terephthaloyl chloride (TPC) 17.29 g (85.16 mmol), in Stir at room temperature for 1 hour. Then, 4.63 g (49.68 mmol) of 4-methylpyridine and 13.04 g (127.75 mmol) of acetic anhydride were added to the flask, and after stirring at room temperature for 30 minutes, the temperature was raised to 70°C using an oil bath, and the mixture was further stirred for 3.5 hours to obtain The reaction solution. The obtained reaction liquid was cooled to room temperature, poured into a large amount of methanol in a linear form, and the precipitated precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Next, the precipitate was dried under reduced pressure at 100°C to obtain a polyimide-based resin (2). The weight average molecular weight of the polyimide-based resin (2) is 455,000. In addition, the imidate ratio of polyimide was 98.9%.

<Production Example 2: Production of Dispersion Liquid 1> The methanol-dispersed organic silicon dioxide (particle size measured by BET method: 27 nm) was replaced with γ-butyrolactone (GBL) to obtain GBL-dispersed organic silicon dioxide (solid content 30.3% by mass). This dispersion liquid is referred to as dispersion liquid 1.

<Production Example 3: Production of varnish (2)> The varnish (2) is mixed in a GBL solvent at room temperature in such a way that the composition ratio of the polymer and the filler becomes 60:40, in which the relative mass of the polymer and the silica becomes 5.7 phr or 35 ppm Add Sumisorb 340 (UVA) and Sumiplast Violet B (BA) in a manner and stir until uniform. A varnish (2) having a solid content of 10.3% by mass and a viscosity of 38,500 at 25°C was obtained.

[Table 1]

<Production Example 4: Film production of raw material film (2)> Cast varnish (2) on PET (polyethylene terephthalate) film ("COSMOSHINE (registered trademark) A4100" manufactured by Toyobo Co., Ltd., thickness 188 μm, thickness distribution ±2 μm) by casting Instead, a coating film is formed. At this time, the linear velocity is 0.3 m/min. Furthermore, the coating film was dried under the following conditions: after heating at 80°C for 10 minutes, at 100°C for 10 minutes, then at 90°C for 10 minutes, and finally at 80°C for 10 minutes. After that, the coating film was peeled off from the PET film to obtain a raw film 2 of 58 μm and a width of 1,190 mm. The weight reduction rate M of the raw material film 2 was 9.2%.

<Production Example 5: Film formation of raw material film (3)> In the same manner as in Production Example 4, a raw material film (3) having a thickness of 58 μm and a width of 690 mm was obtained. The mass reduction rate M of the raw material film 2 is 9.3%.

<Production Example 6: Film formation of raw material film (4)> A raw material film 3 having a thickness of 34 μm and a width of 690 mm was obtained in the same manner as in Production Example 5 except that the linear velocity was changed to 0.6 m/min. The mass reduction rate M of the raw film 3 is 9.6%.

<Production Example 7: Film formation of raw material film (5)> The varnish (1) was cast on PET (polyethylene terephthalate) film ("COSMOSHINE A4100" manufactured by Toyobo Co., Ltd., thickness 188 μm, thickness distribution ±2 μm) to form a coating film . At this time, the linear velocity was 0.4 m/min, and the coating film was dried under the following conditions: after heating at 80°C for 10 minutes, at 100°C for 10 minutes, then at 90°C for 10 minutes, and finally at 80°C Heat for 10 minutes. Thereafter, the coating film was peeled from the PET film to obtain a raw film (5) having a thickness of 90 μm and a width of 865 mm. The mass reduction rate M of the raw film 4 is 9.4%.

<Example 1> For the raw material film (1) of Production Example 4, a tenter dryer (structure of 1 to 6 chambers) using a jig as a holding device was used to remove the solvent to obtain a polyimide film 1 with a thickness of 50 μm. Set the temperature in the dryer to 200°C and adjust it as follows: clamp holding width 25 mm, film transport speed 0.9 m/min, film width at the inlet of the dryer (distance between clamps) and film width at the outlet of the dryer The ratio becomes 0.98, the wind speed of each room becomes 13.5 m/s (room 1), 13 m/s (room 2), 11 m/s (rooms 3~6), and NOK KLUBER( Co., Ltd.) manufactures BARRIIERTA J400V as lubricating oil and processes it. From the position where the clamp was unwound at a position 1 m after the film left the dryer, the combined film shrinkage was performed for a total of 52 mm of relaxation. Its relaxation rate is equivalent to 4.6%. After the film is unwound from the jig, the jig portion is torn off, a PET-based protective film is attached to the film, and wound up to a 6-inch core made by ABS to obtain a rolled film. The phase difference, optical characteristics and residual solvent amount of the film processed by the tenter dryer are shown in Table 1.

<Example 2> A polyimide film 2 with a thickness of 50 μm was obtained except that the amount of relaxation was changed to 34 mm so that the relaxation rate was equivalent to 3.0%, and processing was performed under the same conditions as in Example 1.

<Comparative Example 1> A polyimide film 3 having a thickness of 50 μm was obtained except that the amount of relaxation was changed to 80 mm so that the relaxation rate was equivalent to 7.2%, and the processing was performed under the same conditions as in Example 1.

<Comparative example 2> A polyimide film 4 having a thickness of 50 μm was obtained except that the relaxation rate was changed to 17 mm so that the relaxation amount was changed to 17 mm, and processing was performed under the same conditions as in Example 1.

<Example 3> Except that the raw material film 2 obtained in Production Example 5 was used, the relaxation amount was set to 40 mm in such a way that the relaxation rate was equivalent to 6.4%, and the processing was performed under the same conditions as in Example 1, to obtain a polyimide with a thickness of 50 μm. Imine film 5.

<Example 4> A polyimide film 6 having a thickness of 50 μm was obtained except that the amount of relaxation was changed to 20 mm so that the relaxation rate was changed to 20 mm, and processing was performed under the same conditions as in Example 3.

<Comparative Example 3> A polyimide film 7 with a thickness of 50 μm was obtained except that the amount of relaxation was changed to 80 mm so that the relaxation rate was equivalent to 12.8%, and processing was performed under the same conditions as in Example 3.

<Comparative Example 4> Except not relaxing, processing was performed under the same conditions as in Example 3 to obtain a polyimide film 8 with a thickness of 50 μm.

<Example 5> Except that the raw material film 4 obtained in Production Example 6 was used, it was processed under the same conditions as in Example 3 to obtain a polyimide film 9 having a thickness of 30 μm.

<Example 6> Divide by a slack ratio equivalent to 1.8%, change the amount of slack to 15 mm, change the ratio of the film width at the inlet of the dryer (distance between clamps) to the film width at the outlet of the dryer to 0.98, and change the transport speed to Other than 0.6 m minutes, processing was performed under the same conditions as in Example 1, to obtain a polyimide film 10 having a thickness of 80 μm.

[Table 2]

[table 3]

(a)‧‧‧Side view (b) ‧‧‧ top view (1)‧‧‧1 (2) Room ‧‧‧2 (3) Room ‧‧‧ (4) Room ‧‧‧‧ (5) Room ‧‧‧‧ (6) Room ‧‧‧ Fa‧‧‧relaxed width relative to one end of film transport direction Fb‧‧‧slack width at the other end W‧‧‧The width of the film just after leaving the dryer W-(Fa+Fb)‧‧‧ Film width after relaxation (X)‧‧‧Relieve the hold

FIG. 1 shows an example of a dryer for manufacturing a transparent resin film of the present invention. Transport the film from the left side to the right side of the paper. (a) shows a side view of the dryer, and the center line shows the state of the film being transported. (b) shows the top view of the dryer, and the square in the center shows the film being transported.

(a)‧‧‧Side view

(b) ‧‧‧ top view

(1)‧‧‧1

(2) Room ‧‧‧2

(3) Room ‧‧‧

(4) Room ‧‧‧‧

(5) Room ‧‧‧‧

(6) Room ‧‧‧

Fa‧‧‧relaxed width relative to one end of film transport direction

Fb‧‧‧slack width at the other end

W‧‧‧The width of the film just after leaving the dryer

W-(Fa+Fb)‧‧‧ Film width after relaxation

(X)‧‧‧Relieve the hold

Claims (3)

A method for manufacturing a transparent resin film, which has The step of holding both ends of a long strip-shaped transparent resin film containing at least one resin selected from the group consisting of polyimide-based resins and polyamidide-based resins, Steps of transporting the held film, The step of setting the width of the film to be held at a specific distance (where the holding portion is not included in the distance) and heat-treating the resin film in a dryer, The width of the resin film leaving the dryer (where the holding portion is not included in the width) becomes 0.90 to 1.20 relative to the width of the resin film just before leaving the dryer (where the holding portion is not included in the width) Steps, and Steps to unhold, In the step of releasing the holding, the ratio of the slack amount (F) of the jig to the width of the film leaving the dryer (where the holding portion is not included in the width) (W) satisfies 1.6≦F/W×100≦7.0 . The manufacturing method according to claim 1, wherein the holding is performed by a plurality of jigs. The manufacturing method according to claim 1 or 2, wherein the content of the organic solvent contained in the resin film after heat treatment is 0.001 to 3% by mass relative to the mass of the resin film.

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