Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
  • B32B27/281—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42 comprising polyimides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/02—Physical, chemical or physicochemical properties
  • B32B7/022—Mechanical properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/06—Interconnection of layers permitting easy separation

Definitions

• the present invention relates to a laminate.
• it relates to a laminate of a polyimide film and a protective film that protects the polyimide film.
• transparent resin films such as polyimide films and polyamide films have been widely used as materials to replace conventionally used glass.
• a transparent resin film is laminated with a protective film on one side to prevent the transparent resin film from being scratched, and a functional layer such as a hard coat layer is formed on the other side.
• the protective film is removed and used for various purposes.
• Patent Documents 1 to 3 Examples of documents describing a laminate of a transparent resin film and a protective film include Patent Documents 1 to 3.
• Patent No. 6376271 Patent No. 6450048 Patent No. 6400875
• the transparent resin film be made thinner from the viewpoint of excellent transparency and suppression of coloration.
• thin transparent resin films have weak stiffness and are unnecessarily soft, so even when laminated with a protective film, the stiffness was not sufficient. For this reason, when the laminate is made into a film roll, there are problems in transportability, such as the tendency for wrinkles to form.
• the thin transparent resin film is easily scratched, it must be handled with care, making it difficult to handle. Further, there is a problem in that wrinkles and scratches are likely to occur when punching the laminate using Thomson type processing or the like.
• Patent Documents 1 to 3 have not been studied in terms of stiffness, transportability (handling properties), suitability for punching, and winding properties, and there is room for improvement.
• the present invention solves the above problems, and provides a laminate of a polyimide film and a protective film that has improved stiffness, transportability (handling performance), suitability for punching, and winding performance, and
• the object of the present invention is to provide a film roll of the laminate.
• the present inventors have found that by setting the product of the elastic modulus and thickness of the laminate of a polyimide film and a protective film within a certain range, the laminate and the It was discovered that the stiffness, transportability, suitability for punching, and winding properties of a film roll of a laminate can be improved, leading to the completion of the present invention.
• the present invention includes the following configuration.
• the protective film has an elastic modulus Epf of 1.0 GPa or more.
• the protective film includes a polyester film and an adhesive layer.
• the laminate of the polyimide film and protective film of the present invention has good stiffness. Furthermore, even when the laminate is made into a film roll, it has excellent conveyance (handling) properties, winding properties, and suitability for punching.
• the polyimide film of the present invention is not particularly limited as long as it has a polyimide structure.
• Examples include aromatic polyimide film, aliphatic polyimide film, alicyclic polyimide film, aromatic polyamide-imide film, aliphatic polyamide-imide film, alicyclic polyamide-imide film, and a mixture thereof.
• it is an aromatic polyimide film, an aliphatic polyimide film, or an alicyclic polyimide film.
• polyimide film is produced by applying a polyamic acid (polyimide precursor) solution obtained by reacting diamines and tetracarboxylic acids in a solvent to a polyimide film production support and drying it to form a green film (hereinafter referred to as "polyamide precursor"). It is obtained by subjecting the green film to a high-temperature heat treatment on a support for producing a polyimide film or in a state peeled from the support to cause a dehydration ring-closing reaction.
• a polyamic acid (polyimide precursor) solution obtained by reacting diamines and tetracarboxylic acids in a solvent
• polyamide precursor green film
• the polyamic acid (polyimide precursor) solution can be applied using conventionally known solutions such as spin coating, doctor blade, applicator, comma coater, screen printing, slit coating, reverse coating, dip coating, curtain coating, and slit die coating. Any means may be used as appropriate.
• the polyimide film of the present invention needs to have a yellowness index (hereinafter also referred to as "yellow index" or "YI") of 10 or less. From the viewpoint of good transparency, it is preferably 8 or less, more preferably 7 or less, even more preferably 6 or less, even more preferably 5 or less, even more preferably 4 or less, Particularly preferably, it is 3 or less.
• the lower limit of the yellowness index of the polyimide film is not particularly limited, but in order to use it as a flexible electronic device, it is preferably 0.1 or more, more preferably 0.2 or more, and still more preferably 0.3 or more. be. When the yellowness index of the polyimide film of the present invention is within the above range, transparency becomes good (transparent polyimide film).
• the method for measuring the yellowness index of the polyimide film is based on the method described in Examples.
• Aromatic tetracarboxylic acids for obtaining colorless and highly transparent polyimide include 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid, 4,4'-oxydiphthalic acid, and 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-benz
• Examples include tetracarboxylic acids and their acid anhydrides.
• dianhydrides having two acid anhydride structures are preferred, particularly 4,4'-(2,2-hexafluoroisopropylidene)diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, Acid dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, and pyromellitic dianhydride are preferred.
• the aromatic tetracarboxylic acids may be used alone or in combination of two or more kinds.
• the amount of copolymerized aromatic tetracarboxylic acids is preferably 50% by mass or more of the total tetracarboxylic acids, more preferably 60% by mass or more, and still more preferably 70% by mass.
• the content is more preferably 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
• dianhydrides having two acid anhydride structures are preferred, particularly 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2,3,4-cyclohexanetetracarboxylic dianhydride.
• Acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride is preferred, and 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride
• Acid dianhydride is more preferred, and 1,2,3,4-cyclobutanetetracarboxylic dianhydride is even more preferred. Note that these may be used alone or in combination of two or more.
• the amount of copolymerized alicyclic tetracarboxylic acids is, for example, preferably 50% by mass or more of the total tetracarboxylic acids, more preferably 60% by mass or more, and even more preferably 70% by mass. % or more, still more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may even be 100% by mass.
• tricarboxylic acids examples include aromatic tricarboxylic acids such as trimellitic acid, 1,2,5-naphthalene tricarboxylic acid, diphenyl ether-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, alkylenes such as ethylene glycol bis trimellitate, propylene glycol bis trimellitate, 1,4-butanediol bis trimellitate, and polyethylene glycol bis trimellitate.
• examples include glycol bistrimelitate, and monoanhydrides and esterified products thereof. Among these, monoanhydrides having one acid anhydride structure are preferred, and trimellitic anhydride and hexahydrotrimellitic anhydride are particularly preferred. Incidentally, these may be used alone or in combination.
• dicarboxylic acids examples include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, 4,4'-oxydibenzenecarboxylic acid, or the above-mentioned aromatic dicarboxylic acids such as 1,6-cyclohexanedicarboxylic acid.
• examples include esterified products.
• aromatic dicarboxylic acids and hydrogenated products thereof are preferred, with terephthalic acid, 1,6-cyclohexanedicarboxylic acid, and 4,4'-oxydibenzenecarboxylic acid being particularly preferred.
• dicarboxylic acids may be used alone or in combination.
• Diamines or isocyanates for obtaining colorless and highly transparent polyimides are not particularly limited, and include aromatic diamines, aliphatic diamines, and alicyclic diamines commonly used in polyimide synthesis, polyamide-imide synthesis, and polyamide synthesis.
• diisocyanates, aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, etc. can be used. From the viewpoint of heat resistance, aromatic diamines are preferred, and from the viewpoint of transparency, alicyclic diamines are preferred. Further, when aromatic diamines having a benzoxazole structure are used, it becomes possible to exhibit high elastic modulus, low thermal shrinkage, and low coefficient of linear expansion as well as high heat resistance. Diamines and isocyanates may be used alone or in combination of two or more.
• aromatic diamines examples 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,
• some or all of the hydrogen atoms on the aromatic ring of the aromatic diamine may be substituted with a halogen atom, an alkyl group or alkoxyl group having 1 to 3 carbon atoms, or a cyano group, and further, Part or all of the hydrogen atoms of the alkyl group or alkoxyl group of ⁇ 3 may be substituted with a halogen atom.
• aromatic diamines having the 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,
• aromatic diamines may be used alone or in combination.
• alicyclic diamines examples include 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, Examples include 1,4-diamino-2-tert-butylcyclohexane and 4,4'-methylenebis(2,6-dimethylcyclohexylamine).
• 1,4-diaminocyclohexane and 1,4-diamino-2-methylcyclohexane are particularly preferred, and 1,4-diaminocyclohexane is more preferred.
• the alicyclic diamines may be used alone or in combination.
• diisocyanates examples include diphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3' - or 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2 '-or 5,3'-or 6,2'-or 6,3'-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, dipheny
• the diisocyanates may be used alone or in combination.
• a polyimide film by using a polyimide film, it has excellent heat resistance. Moreover, since it is a polyimide film, it can be suitably cut with an ultraviolet laser.
• the glass transition temperature of the polyimide film of the present invention is preferably 300°C or higher. Since the heat resistance becomes good, the temperature is more preferably 350°C or higher, still more preferably 375°C or higher, and even more preferably 400°C or higher. It is preferable that the glass transition temperature is within the above range because it can withstand a heat treatment process of 300° C. or higher during the production of flexible electronic devices. Although the upper limit is not particularly limited, it may be 500°C or less industrially. The glass transition temperature of the polyimide film was measured by the method described in Examples.
• the thickness of the polyimide film is preferably 3 ⁇ m or more, more preferably 7 ⁇ m or more, still more preferably 14 ⁇ m or more, and even more preferably 20 ⁇ m or more.
• the upper limit of the thickness of the polyimide film is preferably 40 ⁇ m or less, more preferably 30 ⁇ m or less. By setting it within the above range, the transparency and stiffness of the polyimide film will be good.
• the average coefficient of linear expansion (CTE) between 30°C and 250°C of the polyimide film is preferably 65 ppm/K or less. More preferably 55 ppm/K or less, still more preferably 45 ppm/K or less, even more preferably 35 ppm/K or less, even more preferably 25 ppm/K or less, even more preferably 15 ppm/K or less It is particularly preferably 10 ppm/K or less. Further, it is preferably -5 ppm/K or more, more preferably -3 ppm/K or more, and even more preferably 1 ppm/K or more.
• the CTE is within the above range, the difference in linear expansion coefficient with a general support (for example, a glass substrate) can be kept small, and the polyimide film and the support will not peel off even if subjected to a process of applying heat. Alternatively, warping of the entire support can be avoided.
• CTE is a factor representing reversible expansion and contraction with respect to temperature.
• the CTE of the polyimide film refers to the average value of the CTE in the coating direction (MD direction) and the CTE in the width direction (TD direction) of the polyimide solution or polyimide precursor solution. The CTE of the polyimide film was measured by the method described in Examples.
• the polyimide film of the present invention preferably has a total light transmittance of 75% or more. Since transparency becomes good, 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.
• the upper limit of the total light transmittance of the polyimide film is not particularly limited, but in order to use it as a flexible electronic device, it is preferably 98% or less, more preferably 97% or less. When the total light transmittance of the polyimide film of the present invention is within the above range, transparency becomes good (transparent polyimide film). The total light transmittance of the polyimide film was measured by the method described in Examples.
• the haze of the polyimide film of the present invention is preferably 1.0 or less, more preferably 0.8 or less, still more preferably 0.5 or less, and even more preferably 0.3 or less.
• the lower limit is not particularly limited, but industrially, there is no problem if it is 0.01 or more, and it may be 0.05 or more.
• transparency becomes good (transparent polyimide film).
• the haze of the polyimide film was measured by the method described in Examples.
• the tensile strength at break of the polyimide film of the present invention is preferably 60 MPa or more, more preferably 80 MPa or more, and still more preferably 100 MPa or more.
• the upper limit of the tensile strength at break is not particularly limited, but is practically less than about 1000 MPa.
• the tensile strength at break is 60 MPa or more, it is possible to prevent the polyimide film from breaking when peeled from the protective film.
• the tensile strength at break of the polyimide film refers to the average value of the tensile strength at break in the machine direction (MD direction) and the tensile strength at break in the width direction (TD direction) of the polyimide film.
• the tensile elongation at break of the polyimide film of the present invention is preferably 1% or more, more preferably 5% or more, and still more preferably 10% or more. When the tensile elongation at break is 1% or more, handling properties are excellent. Note that the tensile elongation at break of the polyimide film refers to the average value of the tensile elongation at break in the machine direction (MD direction) and the tensile elongation at break in the width direction (TD direction) of the polyimide film.
• the tensile modulus of the polyimide film of the present invention is preferably 3.0 GPa or more, more preferably 4.0 GPa or more, even more preferably 5.0 GPa or more, and even more preferably 6.0 GPa or more.
• the tensile modulus is 3.0 GPa or more, the polyimide film undergoes little elongation deformation when peeled from the protective film, resulting in excellent handling properties.
• the tensile modulus of the polyimide film is 3.0 GPa or more, the width of vibration during conveyance or handling of the laminate in the laminate with the protective film can be kept small.
• the tensile modulus is preferably 9.0 GPa or less, more preferably 8.8 GPa or less, still more preferably 8.5 GPa or less.
• the polyimide film can be used as a flexible film.
• the tensile modulus of the polyimide film is 9.0 GPa or less, warping of the laminate after heating can be suppressed in the laminate of the protective film and the polyimide film.
• the storage modulus of the polyimide film at 280° C. can be easily set to 9.0 GPa or less.
• the storage modulus of the polyimide film at 280° C. is preferably 9.0 GPa or less, more preferably 8.0 GPa or less, still more preferably 7.0 GPa or less. Moreover, it is preferably 0.1 GPa or more, more preferably 0.5 GPa or more, and still more preferably 1.0 GPa or more. Note that the tensile modulus and storage modulus of the polyimide film refer to the average values of the tensile modulus in the machine direction (MD direction) and the tensile modulus in the width direction (TD direction) of the polyimide film.
• the thickness unevenness of the polyimide film of the present invention is preferably 20% or less, more preferably 12% or less, still more preferably 7% or less, particularly preferably 4% or less. If the thickness unevenness exceeds 20%, it tends to be difficult to apply to narrow areas.
• the preferred range of thickness irregularities of the protective film and the laminate and the method of measuring the thickness irregularities are the same as the preferred range and measuring method of the polyimide film. be.
• the polyimide film of the present invention is preferably obtained in the form of a rolled polyimide film having a width of 300 mm or more and a length of 10 m or more at the time of manufacture. More preferably, it is in the form of a film.
• the polyimide film When the polyimide film is wound into a roll, it becomes easy to transport the polyimide film in the form of a roll.
• the polyimide film in order to ensure handling properties and productivity, about 0.03 to 3% by mass of lubricant (particles) with a particle size of about 10 to 1000 nm is added and contained in the polyimide film. It is preferable to provide fine irregularities on the film surface to ensure slipperiness.
• the particle size of the lubricant is preferably 20 to 500 nm, more preferably 30 to 300 nm, and even more preferably 50 to 200 nm. By setting the particle size of the lubricant to 10 nm or more, sufficient slipperiness can be achieved with respect to the amount added. Furthermore, by setting the particle size of the lubricant to 1000 nm or less, problems such as a decrease in mechanical strength and clouding of the film can be reduced.
• the fine irregularities on the surface of the polyimide film are preferably provided on the surface opposite to the protective film (the surface not in contact with the protective film), and the surface in contact with the protective film is preferably free of the fine irregularities.
• the polyimide film may or may not have an adhesive layer on the surface in contact with the protective film.
• the surface opposite to the protective film does not have an adhesive layer.
• the polyimide film preferably has an arithmetic mean height Sa of the surface not in contact with the protective film of 0.001 ⁇ m or more, more preferably 0.003 ⁇ m or more, and still more preferably 0.005 ⁇ m or more. Moreover, it is preferably 0.100 ⁇ m or less, more preferably 0.050 ⁇ m or less, and still more preferably 0.020 ⁇ m or less. By setting it within the above range, the static friction coefficient ⁇ s and the dynamic friction coefficient ⁇ d with the protective film can be reduced.
• the arithmetic mean height Sa of the polyimide film can be controlled by the manufacturing conditions during molding (temperature, linear speed, nip roll surface waviness, nip pressure, etc.).
• the arithmetic mean height tends to become smaller when the molding temperature is lowered, and the arithmetic mean height also tends to become smaller when the linear speed is increased or the nip pressure is lowered. It can also be controlled by the storage conditions (temperature, humidity, storage time) of the polyimide film after molding.
• the protective film of the present invention is not particularly limited as long as it is a peelable film that can protect the surface of the polyimide film, but it is preferably a polyester film, and more preferably contains a polyethylene terephthalate structure (hereinafter also referred to as PET structure).
• PET structure is contained in an amount of 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass.
• the protective film can exhibit an appropriate tensile modulus.
• the appropriate tensile modulus is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 1.0 GPa or more, more preferably 2.0 GPa or more, and Preferably it is 3.0 GPa or more, and even more preferably 3.5 GPa or more.
• the protective film is a polyethylene terephthalate film.
• the protective film may or may not have an adhesive layer on the surface in contact with the polyimide film, but preferably has an adhesive layer. That is, it is preferable to have an adhesive layer between the polyimide film and the protective film. By having an adhesive layer in the protective film, self-adsorption properties can be exhibited.
• the adhesive layer is not particularly limited, but for example, a urethane-based, silicone-based, or acrylic-based adhesive layer can be used, and a silicone-based or acrylic-based adhesive layer is preferred.
• the adhesive layer can be produced by applying an adhesive dissolved in a solvent and drying it.
• the surface opposite to the polyimide film (the surface not in contact with the polyimide film) preferably does not have an adhesive layer.
• the thickness of the protective film is preferably 10 ⁇ m or more, more preferably 20 ⁇ m or more, even more preferably 30 ⁇ m or more, even more preferably 40 ⁇ m or more, even more preferably 50 ⁇ m or more, Still more preferably, it is 60 ⁇ m or more. Moreover, it is preferably 200 ⁇ m or less, and more preferably 150 ⁇ m or less. By setting it within the above range, when laminated with a polyimide film, the stiffness and conveyance properties (handling properties) of the laminate will be good.
• the thickness of the protective film includes the adhesive layer.
• the thickness of the protective film is preferably the same as or thicker than the thickness of the polyimide film.
• the ratio of the thickness of the protective film to the thickness of the polyimide film is preferably 1.0 or more, more preferably 1.1 or more, and even more preferably is 1.5 or more, even more preferably 2.0 or more, particularly preferably 2.5 or more. Moreover, it is preferably 10 or less, more preferably 8 or less, and still more preferably 6 or less.
• the protective film may contain various additives in the protective film and/or the adhesive layer, if necessary.
• the additives include fillers, antioxidants, light stabilizers, antigelation agents, organic wetting agents, antistatic agents, surfactants, pigments, and dyes.
• the arithmetic mean height Sa of the surface not in contact with the polyimide film of the protective film is preferably 0.005 ⁇ m or more, more preferably 0.010 ⁇ m or more, and still more preferably 0.020 ⁇ m or more. Moreover, it is preferably 1.000 ⁇ m or less, more preferably 0.500 ⁇ m or less, and still more preferably 0.200 ⁇ m or less. By setting it within the above range, the static friction coefficient ⁇ s and the dynamic friction coefficient ⁇ d with the protective film can be reduced.
• the arithmetic mean height Sa of the protective film can be controlled by manufacturing conditions (temperature, linear speed, surface waviness of the nip roll, nip pressure, etc.) during molding of the protective film.
• the arithmetic mean height tends to become smaller when the molding temperature is lowered, and the arithmetic mean height also tends to become smaller when the linear speed is increased or the nip pressure is lowered. It can also be controlled by the storage conditions (temperature, humidity, storage time) of the protective film after molding. When using a commercially available protective film, it is also possible to select a suitable one by measuring the arithmetic mean height of the protective film used before laminating it with the polyimide film.
• the laminate of the present invention is a laminate in which the protective film is laminated on at least one surface of the polyimide.
• a protective film may be laminated on both sides of the polyimide.
• the product of the tensile modulus E1 (unit: GPa) of the laminate and the film thickness T1 (unit: ⁇ m) of the laminate is 200 or more and 340 or less.
• the lower limit is preferably 220 or more, more preferably 240 or more, still more preferably 260 or more, particularly preferably 280 or more.
• the upper limit value is preferably 335 or less, more preferably 330 or less, still more preferably 325 or less, particularly preferably 320 or less.
• the stiffness and transportability (handling performance) of the laminate are improved. Adjustment within the above range can be achieved by appropriately combining the polyimide film and the protective film.
• the product of E1 and T1 exceeds the lower limit, the stiffness of the laminate is sufficiently strong and wrinkles are less likely to occur during transportation, punching, etc.
• the laminate below the above upper limit, the laminate is not too stiff and is moderately flexible, so it follows the rollers well during the process of winding up the laminate, and there are no gaps between the core material and the laminates or between the laminates. It is possible to obtain a laminate film roll that is evenly and densely packed without any voids.
• the coefficient of static friction ⁇ s between the surface of the polyimide film opposite to the protective film and the surface of the protective film opposite to the polyimide film is 0.70 or less.
• a laminate having a dynamic friction coefficient ⁇ d of 0.60 or less is preferable.
• the static friction coefficient ⁇ s is more preferably 0.65 or less, further preferably 0.60 or less, particularly preferably 0.55 or less.
• the lower limit of the static friction coefficient ⁇ s is not particularly limited, and may be industrially 0.10 or more, or 0.20 or more.
• the dynamic friction coefficient ⁇ d is more preferably 0.55 or less, further preferably 0.50 or less, particularly preferably 0.45 or less.
• the lower limit of the dynamic friction coefficient ⁇ d is not particularly limited, and may be industrially 0.10 or more, or 0.20 or more.
• the static friction coefficient ⁇ s 0.70 or less and the dynamic friction coefficient ⁇ d 0.60 or less there is no particular limitation, but for example, a method of adding a lubricant to the polyimide film can be mentioned.
• a method of adding a lubricant to the polyimide film can be mentioned.
• the smaller the surface roughness the larger the value of the friction coefficient. This means that the smoother the surface, the greater the friction, and one possible way to reduce the coefficient of friction is to add a lubricant to the polyimide film to impart fine roughness to the surface.
• the static friction coefficient ⁇ s and the dynamic friction coefficient ⁇ d change depending on the degree and properties of the surface of the polyimide film or protective film, so they can be controlled, for example, by coating the surface with an appropriate film and modifying it.
• the sum of the arithmetic mean height Sa of the polyimide film and the arithmetic mean height Sa of the protective film is preferably from 0.030 ⁇ m to 1.000 ⁇ m, more preferably from 0.050 ⁇ m to 0.0 ⁇ m. .800 ⁇ m or less, more preferably 0.100 ⁇ m or more and 0.700 ⁇ m or less.
• ⁇ Polymerization example 1 Preparation of polyamic acid solution A1> After purging the inside of the reaction vessel equipped with a nitrogen introduction tube, a reflux tube, and a stirring bar with nitrogen, 9.61 g of 2,2'-bis(trifluoromethyl)benzidine (TFMB) and 3.91 g of pyromellitic dianhydride were added. (PMDA), 3.51 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added as a solid, followed by N,N-dimethylacetamide (DMAc, 96.65 g).
• TFMB 2,2'-bis(trifluoromethyl)benzidine
• BPDA 3,3',4,4'-biphenyltetracarboxylic dianhydride
• DMAc N,N-dimethylacetamide
• Polyamic acid solution A1 was coated on the non-slip surface of polyethylene terephthalate film A4100 (manufactured by Toyobo Co., Ltd.) using a comma coater so that the final film thickness was adjusted to 23 ⁇ m. This was dried at 90 to 110°C for 10 minutes.
• the polyamic acid film that has obtained self-supporting properties after drying 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 to prevent the film from breaking and
• the pin sheet interval was adjusted to avoid unnecessary sagging, and the sheet was conveyed, and heated at 250° C. for 3 minutes, 300° C. for 3 minutes, and 370° C. for 6 minutes to advance the imidization reaction. Thereafter, the film was cooled to room temperature for 2 minutes, and portions with poor flatness at both ends of the film were cut off using a slitter to obtain 500 m of polyimide film F1 with a width of 450 mm.
• Polyimide film F2 was obtained in the same manner as polyimide film F1 except that the final film thickness was changed to 15 ⁇ m.
• ⁇ Polymerization example 2 Preparation of polyamic acid solution A2> After purging the inside of the reaction vessel equipped with a nitrogen introduction tube, a reflux tube, and a stirring bar with nitrogen, 11.26 g of 2,2'-bis(trifluoromethyl)benzidine (TFMB) and 3.43 g of 1,2,3 , 4-cyclobutanetetracarboxylic dianhydride (CBDA), 3.60 g 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 1.63 g 4,4'-oxydiphthalic acid After adding dianhydride (ODPA) as a solid, N,N-dimethylacetamide (DMAc, 112.93 g) was added to a total amount of 0.15% by mass based on the total amount of polymer solids in the polyamic acid solution.
• TFMB 2,2'-bis(trifluoromethyl)benzidine
• CBDA 4-cyclobutanetetracarboxy
• Polyimide solution A2 was coated on the non-slip surface of polyethylene terephthalate film A4100 (manufactured by Toyobo Co., Ltd.) using a comma coater so that the final film thickness was adjusted to 24 ⁇ m.
• the polyethylene terephthalate film A4100 was passed through a hot air oven and wound up, and at this time was dried at 100° C. for 10 minutes.
• the polyamic acid film that has obtained self-supporting properties after drying 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 to prevent the film from breaking and
• the pin sheet interval was adjusted to avoid unnecessary sagging, and the sheet was conveyed and heated under the conditions of 200° C. for 3 minutes, 250° C. for 3 minutes, and 300° C. for 6 minutes to advance the imidization reaction. Thereafter, the film was cooled to room temperature for 2 minutes, and portions with poor flatness at both ends of the film were cut off using a slitter to obtain 500 m of polyimide film F3 with a width of 450 mm.
• Polyimide film F4 was obtained in the same manner as polyimide film F3 except that the final film thickness was changed to 25 ⁇ m.
• Polyimide film F5 was obtained in the same manner as polyimide film F3 except that the final film thickness was changed to 41.5 ⁇ m.
• Polyimide film F6 was obtained in the same manner as polyimide film F1 except that the final film thickness was changed to 42 ⁇ m.
• Protective films B1 and B2 were produced and used as follows. Commercially available protective films B3 to B5 were used. B1 to B3 are PET-based protective films, and B4 to B5 are PE (polyethylene)-based protective films.
• PET film Toyobo Co., Ltd., A4100, 25 ⁇ m, 50 ⁇ m (polyethylene terephthalate film)
• an adhesive composition C1 100 parts by mass of the acrylic resin and 3 parts by mass of Coronate L (manufactured by Tosoh Corporation, polyisocyanate for paints) were mixed to obtain an adhesive composition C1.
• the obtained adhesive composition C1 was applied onto a polyethylene terephthalate (PET) film (A4100, thickness 25 ⁇ m) manufactured by Toyobo Co., Ltd. that had been subjected to corona treatment in advance, and the solvent was removed by drying at 100 ° C.
• PET polyethylene terephthalate
• Example 1 The protective film B1 from which the release film has been removed is pasted onto the polyimide film F1 produced in Production Example 1 above so that the adhesive layer is in contact with the polyimide film to form a laminate, which is wound at 50N around a winding core with an outer diameter of 175 mm. A laminate roll 1 was obtained by winding it up into a roll under tension. The results are shown in Table 1.
• T1 ⁇ Measurement of laminate thickness (T1 ( ⁇ m))>
• the thickness (T1) of the laminate was measured using a high-precision digimatic micrometer (manufactured by Mitutoyo Co., Ltd., MDH-25M).
• the entire width was measured at 10 m intervals in the flow direction at two locations at both ends and one location at the center in the width direction, and the average value is shown in Table 1 as the results.
• ⁇ Protective film thickness Tpf ( ⁇ m) measurement> The thickness of the protective film was measured using a high-precision digimatic micrometer (manufactured by Mitutoyo Co., Ltd., MDH-25M). The entire width was measured at 10 m intervals in the flow direction at two locations at both ends and one location at the center in the width direction, and the average value is shown in Table 1 as the results.
• Tpi ⁇ Measurement of polyimide film thickness Tpi ( ⁇ m)>
• the thickness of the polyimide film was measured using a high-precision digimatic micrometer (manufactured by Mitutoyo Co., Ltd., MDH-25M).
• the entire width was measured at 10 m intervals in the flow direction at two locations at both ends and one location at the center in the width direction, and the average value is shown in Table 1 as the results.
• ⁇ Windability of laminate> The windability of the laminate was determined by visually observing the appearance of laminate rolls 1 to 9 and grading it as " ⁇ " or "x" according to the following criteria. ⁇ : Air entrapment (bulge) between the laminates was not observed. ⁇ : Air entrapment (bulge) between the laminates was confirmed.
• Total light transmittance The total light transmittance (TT) of the film was measured using HAZEMETER (NDH5000, manufactured by Nippon Denshoku Co., Ltd.). A D65 lamp was used as a light source. Note that similar measurements were performed three times and the arithmetic mean value was used.
• ⁇ Haze> The haze of the film was measured using HAZEMETER (NDH5000, manufactured by Nippon Denshoku Co., Ltd.). A D65 lamp was used as a light source. Note that similar measurements were performed three times and the arithmetic mean value was used.
• the present invention can provide a laminate with improved stiffness, transportability (handling performance), punching suitability, and winding performance.
• the laminate described on the left can be expected to be used, for example, as a material to replace glass that has been conventionally used in the displays of various image display devices, and will contribute to making the displays of various image display devices thinner, lighter, and more flexible. can be expected.

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• 2023
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