Film, polarizing plate, and hot-bending molded body

Abstract

Provided are a thin film which has a low transmittance of light rays having a wavelength of 400 nm or less and a high transmittance of light rays having a wavelength of 420 nm or more, and which is not susceptible to the occurrence of roll scale during production, and a polarizing plate and a hot-bending molded article. The film contains 0.3-2.9 parts by mass of an ultraviolet absorber having a triazine structure per 100 parts by mass of a bisphenol A polycarbonate resin, the thickness of the film is 200-600 [mu] m, the average light transmittance of the film at a wavelength of 250-400 nm is 3% or less, and the light transmittance of the film at a wavelength of 420 nm is 30% or more.

Description

TECHNICAL FIELD

[0001] The present application relates to a film, a polarizing plate, and a heat-bent molded body. In particular, it relates to a film in which a polycarbonate resin is a main component. BACKGROUND

[0002] Polycarbonate resins are produced by condensation polymerization of an aromatic diol such as bisphenol A and a carbonate precursor such as phosgene, and have excellent impact strength, numerical stability, heat resistance, and transparency, and are widely used in the fields of outer packaging materials for electrical and electronic products, automobile parts, building materials, optical elements, and the like.

[0003] On the other hand, in the case of optical lenses for sunglasses and the like, it is necessary to have a transmittance that neither affects the field of view nor produces glare with respect to external light sources. Furthermore, it is also necessary to protect the eyes from harmful light rays of specific wavelengths such as ultraviolet rays. Therefore, various technologies have been developed to use polycarbonate resins having excellent optical properties in addition to mechanical properties for optical lenses for outdoor activities such as sunglasses (Patent Literature 1, Patent Literature 2, and the like).

[0004] PRIOR ART DOCUMENTS PATENT LITERATURE Patent Literature 1: Japanese Patent Application Publication No. 2019-202542 Patent Literature 2: International Publication No. 2019 / 066493 SUMMARY

[0005] PROBLEMS TO BE SOLVED BY THE INVENTION Hitherto, technologies have been studied in which an ultraviolet absorber is compounded in a polycarbonate resin for a lens for sunglasses.

[0006] However, when it is necessary to give the sunglasses a vision correction function, the thickness of the lens varies depending on the degree of the eyeglasses. Therefore, it is necessary to compound the ultraviolet absorber in a layer other than the lens. Among them, the sunglasses and the eyeglasses have a layer structure as shown in, for example, Figure 1 Specifically, they have a lens 1 and a polarizing film 2, and a polarizing film substrate 3 and 4 are usually provided on both side surfaces of the polarizing film 2. Among them, in the case where the ultraviolet absorber is not compounded in the lens 1, it is considered to compound the ultraviolet absorber in the polarizing film substrate 3 or the polarizing film substrate 4.

[0007] However, the polarizing film substrate needs to be as thin as 200 to 600 μm or so, and it is also necessary to be able to shield light of a wavelength of 400 nm or less but transmit light of a wavelength of 420 nm or more. In addition, the present inventors have found out through their studies that, in the case where the ultraviolet absorber is compounded in a thin film as thin as 200 to 600 μm or so, the ultraviolet absorber sometimes volatilizes, and roll fouling occurs at the time of film molding.

[0008] The present application has an object to solve the problem, and to provide a film, and a polarizing plate and a heat-bent molded body, wherein the film is a thin film, has a low light transmittance at a wavelength of 400 nm or less and a high light transmittance at a wavelength of 420 nm or more, and is less likely to cause roll marks at the time of production.

[0009] Technical solution for solving the problem Based on the above problem, the inventors of the present application have conducted studies, and as a result, have found that the above problem can be solved by using a specific ultraviolet absorber at a set ratio and adjusting the light transmittance.

[0010] Specifically, the above problem can be solved by the following solution.

[0011] <1> A film, wherein, with respect to 100 parts by mass of a bisphenol A type polycarbonate resin, 0.3 to 2.9 parts by mass of an ultraviolet absorber having a triazine structure is contained, The film has a thickness of 200 to 600 μm, The film has an average light transmittance at a wavelength of 250 to 400 nm of 3% or less, and a light transmittance at a wavelength of 420 nm of the film of 30% or more.

[0012] <2> The film according to <1>, wherein the ultraviolet absorber contains a compound represented by formula (UV-1). (In formula (UV-1), R 1 is a hydrocarbon group having 1 to 10 carbon atoms, or a group in which a hydrocarbon group having 1 to 10 carbon atoms is combined with -O- and / or -C(=O)-, R 2 ~R 4 are each independently a hydroxyl group, a hydrocarbon group having 1 to 10 carbon atoms, or a group in which a hydrocarbon group having 1 to 10 carbon atoms is combined with -O- and / or -C(=O)-, n2 is an integer of 0 to 3, n3 and n4 are each independently an integer of 0 to 4. <3> The film according to <2>, wherein n3 and n4 are each independently an integer of 1 to 4.

[0013] <4> The film according to <1>, wherein the ultraviolet absorber contains a compound represented by formula (UV-2). (In formula (UV-2), R 11 and R 31 , R 41are each independently an aliphatic hydrocarbon group having 3 to 10 carbon atoms, R 2 、R 32 and R 42 Each independently represents a hydroxyl group, a hydrocarbon group having 1 to 10 carbon atoms, or a group consisting of a hydrocarbon group having 1 to 10 carbon atoms and -O- and / or -C(=O)-, n2, n3-1 and n4-1 are each independently an integer from 0 to 3. <5> The film according to <1>, wherein the ultraviolet absorber contains a compound represented by formula (UV-3). (In formula (UV-3), R 11 and R 31 、R 41 are each independently an aliphatic hydrocarbon group having 3 to 10 carbon atoms. <6> The film according to any one of <1> to <5>, wherein the film has a light transmittance of 3% or less at a wavelength of 400 nm.

[0014] <7> The film according to any one of <1> to <6>, wherein the difference between the light transmittance of the film at a wavelength of 420 nm and the light transmittance of the film at a wavelength of 400 nm is 35% or more.

[0015] <8> A polarizing plate comprising the film according to any one of <1> to <7> and a polarizing film.

[0016] <9> A heat-bent article, which is the heat-bent article of the polarizing plate described in <8>.

[0017] Effects of the Invention According to the present invention, a film, a polarizing plate and a heat-bent molded body can be provided, wherein the film is a thin film with low transmittance for light with a wavelength below 400nm and high transmittance for light with a wavelength above 420nm, and is not prone to roller scale during production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram for explaining an example of the layer structure of the molded article according to the embodiment of the present invention. DETAILED DESCRIPTION

[0019] Hereinafter, specific embodiments for implementing the present invention (hereinafter referred to as "embodiments of the present invention") will be described in detail. It should be noted that the following embodiments of the present invention are examples for explaining the present invention, and the present invention is not limited to the embodiments of the present invention.

[0020] Note that, in the present specification, "~" is used in the meaning that the numerical value recited immediately before and after it is included as the lower limit value and the upper limit value.

[0021] In the present specification, each physical property value and characteristic value indicates the value at 23°C unless otherwise specified.

[0022] In the present specification, the weight average molecular weight is measured by gel permeation chromatography unless otherwise specified.

[0023] Specifically, a gel permeation chromatography device is used with an LC-20AD system (manufactured by Shimadzu Corporation) as a spectrum column, and an LF-804 (manufactured by Shodex Corporation) is connected thereto. The column temperature is set to 40°C. An RI detector of RID-10A (manufactured by Shimadzu Corporation) is used as the detector. Chloroform is used as the eluent, and a standard polystyrene manufactured by Tosoh Corporation is used to create a calibration curve.

[0024] In the present specification, the glass transition temperature (Tg) is a value measured according to differential scanning calorimetry (DSC) based on ISO 11357 unless otherwise specified. According to the conditions of differential scanning calorimetry (DSC measurement), the temperature is raised and lowered twice in a cycle, and the glass transition temperature at the time of the second cycle of temperature increase is measured.

[0025] The intersection of the straight line extending the baseline on the low temperature side to the intersection of the tangent lines of the inflection points is set as the glass transition temperature Tg. The measurement start temperature is 30°C, the temperature increase rate is 10°C / min, the temperature reaching temperature is 250°C, and the temperature decrease rate is 20°C / min. The unit is expressed in °C.

[0026] The measurement device uses a differential scanning calorimeter (DSC, "DSC 7020" manufactured by Hitachi High-Tech Science Corporation).

[0027] The "film" and the "sheet" in the present specification each refer to a molded body that is relatively thin in thickness relative to length and width, and is substantially flat. In addition, the "film" and the "sheet" in the present specification can be single-layered or multi-layered.

[0028] In the case of the measurement method and the like described in the specifications according to the present specification, which differ depending on the year, the standards based on the point in time of January 1, 2023 are used unless otherwise specified.

[0029] Figure 1 The scale and the like of the drawings may not be consistent with the actual ones.

[0030] The film of the present embodiment is characterized in that, with respect to 100 parts by mass of a bisphenol A-type polycarbonate resin, 0.3 to 2.9 parts by mass of an ultraviolet absorber having a triazine structure is contained, the thickness of the film is 200 to 600 μm, the average light transmittance of the film at a wavelength of 250 to 400 nm is 3% or less, and the light transmittance of the film at a wavelength of 420 nm is 30% or more.

[0031] By having such a configuration, a film having a low light transmittance at a wavelength of 400 nm or less, a high light transmittance at a wavelength of 420 nm or more, and being less likely to cause roll marks during production can be provided. Furthermore, the light transmittance at a wavelength of 400 nm can be effectively reduced, and the light transmittance at a wavelength of 420 nm can be effectively increased. That is, the change in light transmittance between a wavelength of 400 nm and a wavelength of 420 nm can be increased.

[0032] In the present embodiment, by using an ultraviolet absorber having a triazine structure (hereinafter sometimes referred to simply as "triazine-based ultraviolet absorber") as the ultraviolet absorber, even if the thickness of the film is reduced, the average light transmittance of light at a wavelength of 250 to 400 nm can be made to be 3% or less, and the light transmittance of the film at a wavelength of 420 nm can be made to be 30% or more. Furthermore, the change in light transmittance between a wavelength of 400 nm and a wavelength of 420 nm can also be increased.

[0033] Furthermore, by using a triazine-based ultraviolet absorber, the ultraviolet absorber can be made less likely to volatilize, and roll marks during film production can be effectively suppressed. The reason for this is presumed to be that a triazine-based ultraviolet absorber has high compatibility with a polycarbonate resin.

[0034] The details of the present embodiment will be described below.

[0035] "Bisphenol A-type polycarbonate resin" The resin composition of the present embodiment contains a bisphenol A-type polycarbonate. The bisphenol A-type polycarbonate of the present embodiment refers to a resin in which 80% by mass or more of the structural units constituting the polycarbonate are structural units represented by formula (A). The proportion of the structural units represented by formula (A) in the polycarbonate resin used in the present embodiment is preferably 85% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and still further preferably 99% by mass or more. The proportion of the structural units represented by formula (A) in the bisphenol A-type polycarbonate resin used in the present embodiment can also be 100% by mass excluding terminal groups.

[0036] Formula (A) In the above formula (A), n is an arbitrary number.

[0037] As the dihydric alcohol component other than bisphenol A constituting the bisphenol A type polycarbonate resin in the embodiment of the present application, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone, 1,1-bis(4-hydroxyphenyl)ethane, bisphenol A, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3-chlorophenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, a,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane, and the like can be exemplified.

[0038] The bisphenol A type polycarbonate resin of the embodiment of the present application is not particularly limited in the molecular weight, and is preferably 20,000 or more, more preferably 30,000 or more, in terms of the weight average molecular weight. In addition, the above weight average molecular weight is preferably 100,000 or less, more preferably 70,000 or less. By setting the above weight average molecular weight to be the lower limit value or more, the strength of the obtained multilayer body for hot bending processing can be improved. Further, by setting the above weight average molecular weight to be the upper limit value or less, there is a tendency that the molding processability is improved.

[0039] Note that, in the embodiment of the present application, two or more kinds of the bisphenol A type polycarbonate resin of the embodiment of the present application having different weight average molecular weights can be used in mixture, in which case, the weight average molecular weight of the mixture is set.

[0040] The bisphenol A type polycarbonate resin of the embodiment of the present application used in the embodiment of the present application preferably has a glass transition temperature (Tg) of 160°C or less, more preferably 155°C or less, further preferably 154°C or less, more further preferably 153°C or less, again further preferably 152°C or less, yet further preferably 151°C or less. In addition, the bisphenol A type polycarbonate resin of the embodiment of the present application used in the embodiment of the present application has a glass transition temperature (Tg) of, for example, 140°C or more, and can also be 143°C or more, 145°C or more, 147°C or more, 148°C or more.

[0041] In the case where the resin composition of the embodiment of the present application contains two or more kinds of bisphenol A type polycarbonate resins, the glass transition temperature of the bisphenol A type polycarbonate resins is the sum of the values obtained by multiplying the glass transition temperature of each bisphenol A type polycarbonate resin by the mass percentage.

[0042] Further, the details of the bisphenol A polycarbonate resin can be referred to the description of Japanese Patent Application Publication No. 2012-144604, paragraphs 0011 to 0020, Japanese Patent Application Publication No. 2019-002023, paragraphs 0014 to 0035, and incorporated herein, as long as the details do not exceed the gist of the embodiments of the present application.

[0043] The content of the bisphenol A polycarbonate resin in the film of the embodiments of the present application is preferably 85% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, still further preferably 97% by mass or more, and yet further preferably 98% by mass or more, of 100% by mass of the film. Further, the content of the bisphenol A polycarbonate resin in the film of the embodiments of the present application is preferably the amount of all components other than the triazine-based ultraviolet absorber in 100% by mass of the film.

[0044] In the case where two or more kinds of bisphenol A polycarbonate resins are contained in the film of the embodiments of the present application, the total amount is preferably within the above range.

[0045] < Triazine-based ultraviolet absorber > In the film of the embodiments of the present application, 0.3 to 2.9 parts by mass of an ultraviolet absorber having a triazine structure (triazine-based ultraviolet absorber) is contained with respect to 100 parts by mass of the bisphenol A polycarbonate resin. By having such a configuration, even if the thickness of the film is reduced, the average light transmittance of light rays having a wavelength of 250 to 400 nm can be reduced, the light transmittance of the film at light rays having a wavelength of 420 nm can be increased, and the change in light transmittance between light rays having a wavelength of 400 to 420 nm can be increased. Further, the roll contamination at the time of manufacturing the film can be effectively suppressed.

[0046] The triazine-based ultraviolet absorber used in the embodiments of the present application is an ultraviolet absorber including a triazine structure, and the kind thereof is not particularly limited, and preferably contains a compound represented by formula (UV-1), more preferably contains a compound represented by formula (UV-2), and further preferably contains a compound represented by formula (UV-3). (In formula (UV-1), R 1 is a hydrocarbon group having 1 to 10 carbon atoms, or a group in which a hydrocarbon group having 1 to 10 carbon atoms is combined with -O- and / or -C(=O)-, R 2 to R 4 are each independently a hydroxyl group, a hydrocarbon group having 1 to 10 carbon atoms, or a group in which a hydrocarbon group having 1 to 10 carbon atoms is combined with -O- and / or -C(=O)-, n2 is an integer of 0 to 3, and n3 and n4 are each independently an integer of 0 to 4. R 1 is a hydrocarbon group having 1 to 10 carbon atoms, or a group formed by combining a hydrocarbon group having 1 to 10 carbon atoms with -O- and / or -C(=O)-, more preferably an aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a group formed by combining an aliphatic hydrocarbon group having 1 to 10 carbon atoms with -O- and / or -C(=O)-, further preferably an aliphatic hydrocarbon group having 1 to 10 carbon atoms, still further preferably a straight-chain aliphatic hydrocarbon group having 3 to 10 carbon atoms, yet further preferably a straight-chain alkyl group having 3 to 10 carbon atoms.

[0047] as the hydrocarbon group (preferably an aliphatic hydrocarbon group, more preferably an alkyl group) for R 1 is preferably 2 or more, more preferably 3 or more, further preferably 4 or more, still further preferably 5 or more, and is preferably 9 or less, more preferably 8 or less, further preferably 7 or less.

[0048] R 2 to R 4 are each independently a hydroxyl group, a hydrocarbon group having 1 to 10 carbon atoms, or a group formed by combining a hydrocarbon group having 1 to 10 carbon atoms with -O- and / or -C(=O)-, at least one of R 2 to R 4 is a hydroxyl group, and at least one of the remaining R 2 to R 4 is a hydrocarbon group having 1 to 10 carbon atoms, or a group formed by combining a hydrocarbon group having 1 to 10 carbon atoms with -O- and / or -C(=O)-.

[0049] The hydrocarbon group having 1 to 10 carbon atoms for R 2 to R 4 may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and is preferably a straight-chain aliphatic hydrocarbon group (preferably a straight-chain alkyl group) or a phenyl group.

[0050] The hydrocarbon group having 1 to 10 carbon atoms for R 2 to R 4 is preferably 2 or more, more preferably 3 or more, further preferably 4 or more, still further preferably 5 or more, and is preferably 9 or less, more preferably 8 or less, further preferably 7 or less.

[0051] n2 is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, further preferably 1.

[0052] n3 and n4 are each independently an integer of 0 to 4, preferably an integer of 1 or more, more preferably an integer of 2 or more, further preferably an integer of 3 or more, still preferably an integer of 4 or less. (In formula (UV-2), R 11 and R 31 , R 41 are each independently an aliphatic hydrocarbon group having 3 to 10 carbon atoms, R 2 , R 32 , and R 42 are each independently a hydroxyl group, a hydrocarbon group having 1 to 10 carbon atoms, or a group in which a hydrocarbon group having 1 to 10 carbon atoms is combined with -O- and / or -C(=O)-, and n2, n3-1, and n4-1 are each independently an integer of 0 to 3.) R 11 , R 31 , and R 41 are each independently an aliphatic hydrocarbon group having 3 to 10 carbon atoms, and the number of carbon atoms of the above aliphatic hydrocarbon group is more preferably 4 or more, further preferably 5 or more, and is preferably 9 or less, more preferably 8 or less, further preferably 7 or less. In addition, the aliphatic hydrocarbon group is preferably a straight-chain aliphatic hydrocarbon group, and more preferably a straight-chain alkyl group.

[0053] The aliphatic hydrocarbon group is preferably a straight-chain aliphatic hydrocarbon group, and more preferably a straight-chain alkyl group, and is preferably a propyl group, a butyl group, a pentyl group, a hexyl group, and more preferably a butyl group, a pentyl group, or a hexyl group.

[0054] R 2 , R 32 , and R 42 are each independently a hydroxyl group, a hydrocarbon group having 1 to 10 carbon atoms, or a group in which a hydrocarbon group having 1 to 10 carbon atoms is combined with -O- and / or -C(=O)-.

[0055] The preferable range of R 2 is the same as that of R 2 in formula (UV-1).

[0056] The preferable range of R 32 and R 42 is each independently preferably a hydroxyl group and an alkyl group having 1 to 3 carbon atoms, and more preferably a hydroxyl group and a methyl group.

[0057] n2 is an integer of 0 to 3, and is preferably 1 or 2, and more preferably 1.

[0058] n3-1 and n4-1 are each independently an integer of 0 to 3, and are preferably 1 or 2, and more preferably 2. (In formula (UV-3), R 11 and R 31 , R 41 are each independently an aliphatic hydrocarbon group having 3 to 10 carbon atoms.) R 11 and R 31, R 41 R1and R2are each independently an aliphatic hydrocarbon group having 3 to 10 carbon atoms, the number of carbon atoms in the aliphatic hydrocarbon group is more preferably 4 or more, further preferably 5 or more, and is preferably 9 or less, more preferably 8 or less, further preferably 7 or less. In addition, the aliphatic hydrocarbon group is preferably a straight-chain aliphatic hydrocarbon group, more preferably a straight-chain alkyl group.

[0059] The aliphatic hydrocarbon group is preferably a straight-chain aliphatic hydrocarbon group, more preferably a straight-chain alkyl group, and is preferably a propyl group, a butyl group, a pentyl group, or a hexyl group, more preferably a butyl group, a pentyl group, or a hexyl group.

[0060] The following illustrates a triazine-based ultraviolet absorber used in the embodiment of the present application. The ultraviolet absorber used in the embodiment of the present application is not limited thereto. The molecular weight of the triazine-based ultraviolet absorber used in the embodiment of the present application is preferably 400 or more, more preferably 500 or more, further preferably 550 or more, more further preferably 610 or more, and still more further preferably 650 or more. By setting the molecular weight of the triazine-based ultraviolet absorber to be the above lower limit value or more, the triazine-based ultraviolet absorber is less likely to volatilize, and it is possible to more effectively suppress roll marks. In addition, the molecular weight of the triazine-based ultraviolet absorber used in the embodiment of the present application is preferably 1000 or less, more preferably 900 or less, and further preferably 800 or less. By setting the molecular weight of the triazine-based ultraviolet absorber to be the above upper limit value or less, there is a tendency to further improve the compatibility with the polycarbonate resin.

[0061] The triazine-based ultraviolet absorber in the film of the embodiment of the present application is 0.3 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 0.6 parts by mass or more, further preferably 0.8 parts by mass or more, more further preferably 1.0 parts by mass or more, and still more further preferably 1.2 parts by mass or more, relative to 100 parts by mass of the bisphenol A-type polycarbonate resin. By setting to the above lower limit value or more, there is a tendency to be able to further reduce the light transmittance of the film at a wavelength of 400 nm. In addition, the upper limit value of the content of the above triazine-based ultraviolet absorber relative to 100 parts by mass of the bisphenol A-type polycarbonate resin is 2.9 parts by mass or less, preferably 2.7 parts by mass or less, more preferably 2.5 parts by mass or less, further preferably 2.4 parts by mass or less, more further preferably 2.3 parts by mass or less, and still more further preferably 2.2 parts by mass or less. By setting to the above upper limit value or less, there is a tendency to be able to more effectively suppress the yellowing of the film.

[0062] The content of the triazine-based ultraviolet absorber in the film according to the embodiment of the present application is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, further preferably 0.6% by mass or more, still further preferably 0.8% by mass or more, yet further preferably 1.0% by mass or more, and even further preferably 1.2% by mass or more, relative to 100% by mass of the film. By setting to the above lower limit value or more, there is a tendency that the transmittance of light at a wavelength of 400 nm of the film can be further reduced. In addition, the upper limit value of the content of the above triazine-based ultraviolet absorber is 2.9% by mass or less, preferably 2.7% by mass or less, more preferably 2.5% by mass or less, further preferably 2.4% by mass or less, still further preferably 2.3% by mass or less, yet further preferably 2.2% by mass or less, relative to 100% by mass of the film. By setting to the above upper limit value or less, there is a tendency that the yellowing of the film can be more effectively suppressed.

[0063] The film according to the embodiment of the present application can contain only one kind of triazine-based ultraviolet absorber, or can contain two or more kinds. In the case of containing two or more kinds, the total content is preferably within the above range.

[0064] <Other Components> The film according to the embodiment of the present application can contain other components than the bisphenol A-type polycarbonate resin and the triazine-based ultraviolet absorber, or can not contain such other components.

[0065] As the other components, for example, antioxidants, release agents, heat stabilizers, flame retardants, flame retardant aids, colorants, antistatic agents, optical brighteners, antifogging agents, flowability improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact resistance improvers, sliding property improvers, hue improvers, acid catchers, and the like can be exemplified.

[0066] In addition, within the scope not departing from the gist of the present application, the film according to the embodiment of the present application can be compounded with the additives described in International Publication No. 2021 / 241471, paragraphs 0047 to 0103, which content is incorporated into the present specification.

[0067] In the case of containing other components, the total content thereof is preferably 0.001 to 3% by mass, more preferably 2% by mass or less, further preferably 1% by mass or less, still further preferably 0.5% by mass or less, yet further preferably 0.1% by mass or less, and can be less than 0.01% by mass.

[0068] The other components can contain only one kind, or can contain two or more kinds. In the case of containing two or more kinds of other components, the total content is preferably within the above range.

[0069] The film of the present embodiment can also be configured so as to substantially not contain a triazine-based ultraviolet absorber other than the compound represented by formula (UV-3). By substantially not contain, it is meant that the content of the triazine-based ultraviolet absorber other than the compound represented by formula (UV-3) is less than 1 mass% of the content of the compound represented by formula (UV-3) contained in the film, and preferably less than 0.1 mass%.

[0070] The film of the present embodiment can contain an ultraviolet absorber other than the triazine-based ultraviolet absorber, or can not contain an ultraviolet absorber other than the triazine-based ultraviolet absorber.

[0071] In the first embodiment of the present embodiment, the film substantially does not contain an ultraviolet absorber other than the triazine-based ultraviolet absorber. By substantially not contain, it is meant that the content of the ultraviolet absorber other than the triazine-based ultraviolet absorber is less than 1 mass% of the content of the triazine-based ultraviolet absorber contained in the film, and preferably less than 0.1 mass%.

[0072] In the second embodiment of the present embodiment, the film is configured so as to substantially not contain a benzotriazole-based ultraviolet absorber. By substantially not contain, it is meant that the content of the benzotriazole-based ultraviolet absorber contained in the film is less than 1 mass% of the content of the triazine-based ultraviolet absorber contained in the film, and preferably less than 0.1 mass%.

[0073] In the third embodiment of the present embodiment, the film contains both a triazine-based ultraviolet absorber and a benzotriazole-based ultraviolet absorber. In the third embodiment, relative to 1 mass of the triazine-based ultraviolet absorber, preferably 1 mass or more of the benzotriazole-based ultraviolet absorber is contained, more preferably 3 mass or more is contained, further preferably 5 mass or more is contained, and preferably 6.5 mass or less is contained, more preferably 7 mass or less is contained, further preferably 8 mass or less is contained. In the third embodiment, the benzotriazole-based ultraviolet absorber can be used as only one kind, or two or more kinds can be used. In the case where two or more kinds are used, the total amount is preferably within the above range. As the benzotriazole-based ultraviolet absorber, the description in paragraphs 0023 to 0025 of Japanese Patent Application Publication No. 2023-025384 can be referred to, and the content is incorporated into the present specification.

[0074] The film of the present embodiment can contain a visible light absorber, or can not contain a visible light absorber.

[0075] The visible light absorber is typically a colorant such as a pigment or a dye.

[0076] The film of the present embodiment can also be configured so as to substantially not contain a visible light absorber. Specifically, the content of the visible light absorber is preferably less than 0.01 mass% of the content of the triazine-based ultraviolet absorber contained in the film of the present embodiment, and more preferably less than 0.001 mass%.

[0077] The film of the present embodiment can also be configured to be substantially free of black pigments (and black colorants). Specifically, the content of black pigments is preferably less than 0.01 mass% of the content of the triazine-based ultraviolet absorber contained in the present embodiment, more preferably less than 0.001 mass%. Furthermore, the black pigments (and black colorants) are preferably less than 1.0 mass ppm, more preferably less than 0.5 mass ppm, in 100 mass parts of the film of the present embodiment.

[0078] The film of the present embodiment can also be configured to be substantially free of yellow pigments (and yellow colorants). Specifically, the content of yellow pigments is preferably less than 0.01 mass% of the content of the triazine-based ultraviolet absorber contained in the present embodiment, more preferably less than 0.001 mass%. Furthermore, the yellow pigments (and yellow colorants) are preferably less than 0.5 mass ppm, more preferably less than 0.1 mass ppm, in 100 mass parts of the film of the present embodiment.

[0079] <Thickness of the film> The film of the present embodiment has a thickness of 200 to 600 μm. By setting the thickness of the above film to be equal to or greater than the lower limit value, the light transmittance of the film at a wavelength of 400 nm can often be further reduced. By setting the thickness of the film to be equal to or less than the upper limit value, the heat bending workability can often be further improved.

[0080] The thickness of the above film is preferably equal to or greater than 250 μm, more preferably equal to or greater than 280 μm, and is preferably equal to or less than 550 μm, more preferably equal to or less than 510 μm, further preferably less than 500 μm, more further preferably equal to or less than 450 μm, still further preferably equal to or less than 400 μm, yet further preferably equal to or less than 350 μm.

[0081] <Light transmittance of the film> The film of the present embodiment has an average light transmittance at a wavelength of 250 to 400 nm of 3% or less, and an average light transmittance at a wavelength of 420 nm of 30% or more.

[0082] The light transmittance at a wavelength of 420 nm of the film of the present embodiment is preferably equal to or greater than 35%, more preferably equal to or greater than 40%, further preferably equal to or greater than 43%, more further preferably equal to or greater than 45%, still further preferably equal to or greater than 47%. The upper limit of the light transmittance at a wavelength of 420 nm of the film of the present embodiment is not particularly limited, but 70% or less is feasible.

[0083] The film of the present embodiment preferably has a light transmittance at a wavelength of 400 nm of 3% or less, more preferably 2% or less, further preferably 1% or less, still further preferably 0.6% or less, yet further preferably 0.1% or less, yet further preferably 0.05% or less. The lower limit of the light transmittance at a wavelength of 400 nm of the film of the present embodiment is not particularly limited, but it is feasible to be higher than 0%.

[0084] The film satisfying the above light transmittance can be obtained, for example, by blending a triazine-based ultraviolet absorber having a prescribed structure in a prescribed amount in a bisphenol A-type polycarbonate resin.

[0085] In particular in the present embodiment, the difference between the light transmittance at a wavelength of 420 nm and the light transmittance at a wavelength of 400 nm of the film is preferably 35% or more, more preferably 40% or more, further preferably 45% or more, still further preferably 47% or more. Furthermore, the upper limit of the difference between the light transmittance at a wavelength of 420 nm and the light transmittance at a wavelength of 400 nm of the film is not particularly limited, but it is feasible to be 80% or less. The difference between the light transmittances is mainly achieved by using a triazine-based ultraviolet absorber (preferably a compound represented by formula (UV-1), more preferably a compound represented by formula (UV-2), further preferably a compound represented by formula (UV-3)) in a prescribed amount.

[0086] The film of the present embodiment preferably has a low YI value (Yellow Index). Specifically, the YI value is preferably 20 or less, more preferably 15 or less. The lower limit of the YI value of the film of the present embodiment can be 0, but it is feasible to be 0.01 or more, and even if it is 3 or more, the required properties can be sufficiently satisfied.

[0087] In particular, by making the difference between the light transmittance at a wavelength of 420 nm and the light transmittance at a wavelength of 400 nm of the film large, and satisfying a low YI value, a more excellent film can be formed.

[0088] <Wind-up> The film of the present embodiment can be made into a wind-up in which the film is wound around a core material.

[0089] <Polarizing Plate> The film of the present embodiment is preferably used as a polarizing plate.

[0090] In an embodiment of the present invention, the polarizer is a sheet in which the film of the embodiment of the present invention, the polarizing film, and the polarizing film substrate are sequentially laminated. That is, the film of the embodiment of the present invention is preferably used as at least one side of the polarizing film substrate of the polarizer. The polarizing film substrate is usually bonded to the polarizing film by an adhesive. In an embodiment of the present invention, the polarizing film substrate on one side of the polarizer can be the film of the embodiment of the present invention, or it can be other polarizing film substrates. The polarizing film substrate on the other side of the polarizer can use a known polarizing film substrate of a polarizer, or it can be the same as the film of the embodiment of the present invention. The polarizing film can be a known product, for example, a product made by absorbing or impregnating iodine or a dichroic organic dye in a polyvinyl alcohol (PVA) film.

[0091] Known adhesives can be used to bond the film, polarizing film substrate, and polarizing film according to an embodiment of the present invention. Examples include acrylic adhesives, polyurethane adhesives, epoxy resin adhesives, silicone adhesives, and polyvinyl alcohol adhesives. Among them, polyurethane adhesives are preferred.

[0092] The thickness of the adhesive is usually 1 μm or more and usually 30 μm or less.

[0093] Furthermore, the polarizing plate according to the embodiment of the present invention may further include a mask or the like provided outside the polarizing film substrate.

[0094] Furthermore, in the embodiment of the present invention, the polarizing plate of the embodiment of the present invention is preferably used as a heat-bent molded body that has been subjected to a heat-bending process, and is particularly preferably used as a polarizing film substrate for the polarizing plate.

[0095] When the film according to the embodiment of the present invention is used for a polarizing plate, it may be provided on either side or both sides of the polarizing film.

[0096] In the first embodiment, the film of the embodiment of the present invention is configured to be located on the concave side of the polarizing film after the heat bending process, for example, Figure 1 Position on one side of the polarizing film substrate 4.

[0097] In the second embodiment, the film of the embodiment of the present invention is configured to be located on the convex side of the polarizing film after the heat bending process, for example, Figure 1 Position on one side of the polarizing film substrate 3.

[0098] In a third embodiment, the film of the embodiment of the present invention is configured to be located on both sides of the polarizing film, for example Figure 1 Both polarizing film substrates 3 and 4 are films according to an embodiment of the present invention.

[0099] It should be noted that in Figure 1In the present embodiment, the polarizing plate, the lens 1, the polarizing film 2, the polarizing film base material 3, 4 are subjected to bending processing, but of course, the case where the bending processing is not performed is also included in the present embodiment.

[0100] In the present embodiment, the polarizing plate is preferably used as a polarizing plate for a liquid crystal display device, a polarizing lens (sunglasses, ski goggles, spectacle lenses with a prescribed power, viewfinder lenses for cameras), a cover plate for various meters, a glass for an automobile, a glass for an electric train, a display panel for a vehicle, a housing for an electronic device, and the like, a rearview mirror for a vehicle, a silver mirror for a helmet, and the like.

[0101] Example The present application is more specifically described below by citing examples. The materials, amounts, proportions, processing contents, processing steps, and the like shown in the following examples can be appropriately changed as long as the gist of the present application is not exceeded. Therefore, the scope of the present application is not limited to the specific examples shown below.

[0102] When the measuring instruments and the like used in the examples are difficult to obtain due to discontinuation of production and the like, other devices having equivalent performance can be used for measurement.

[0103] 1. Raw materials Bisphenol A polycarbonate sheet resin: S-3000 manufactured by Mitsubishi Gas Chemical Company, Inc. Ultraviolet absorber B1: LA-F70, manufactured by ADEKA Corporation B2: LA-31, manufactured by ADEKA Corporation Examples 1 to 2, Comparative Examples 1 to 6 <Manufacture of film> A polycarbonate resin film was manufactured by the following method.

[0104] Each component described in Table 1 was weighed in the amount described in Table 1 (expressed in parts by mass in Table 1). Then, after mixing in a mixer for 15 minutes, a T-shaped die melt extruder of a twin-screw segmented extruder (manufactured by Japan Orient Techno Machine Co., Ltd., "2D30W2") having a barrel diameter of 25 mm, a screw with L / D = 30, and a vent was used to extrude in a molten state under the conditions of a discharge amount of 8 Kg / h and a screw rotation speed of 100 rpm, and only the first roll of a film-sheet recycling device (manufactured by Japan Orient Techno Machine Co., Ltd., "FT3W20") was used for cooling and solidification to manufacture a polycarbonate resin film. This was performed under the conditions of a barrel die temperature of 280°C and a roll temperature of 130°C.

[0105] The adjustment of the thickness of the finally obtained film was performed by changing the roll speed of the first roll, and the period became the thickness shown in Table 1.

[0106] Average light transmittance of light rays of wavelength 250 to 400 nm For the obtained film, the average light transmittance of light rays of wavelength 250 to 400 nm was measured.

[0107] Specifically, using a spectrophotometer, the transmittance of the film at wavelengths of 250 to 400 nm (unit: %) was measured under conditions of a scanning speed of 300 nm / min and a sampling interval of 1 nm. The average value was calculated from the light transmittance value for each 1 nm wavelength.

[0108] At the time of measurement, a spectrophotometer U-4100 (manufactured by Hitachi High-Technologies Corporation) was used.

[0109] The evaluation was performed in stages as described below.

[0110] A: 3% or less B: more than 3% and 10% or less C: more than 10% Light transmittance at wavelength 420 nm For the obtained film, the light transmittance at wavelength 420 nm was measured. The measurement of light transmittance was performed in the same manner as the measurement of the average light transmittance of light rays of wavelength 250 to 400 nm described above.

[0111] Light transmittance at wavelength 400 nm For the obtained film, the light transmittance at wavelength 400 nm was measured. The measurement of light transmittance was performed in the same manner as the measurement of the average light transmittance of light rays of wavelength 250 to 400 nm described above.

[0112] Roller dirt For the roller used at the time of film production, it was visually confirmed whether or not roller dirt was present. The confirmation of the presence or absence of roller dirt was performed by five experts in accordance with the following standards, with the majority principle.

[0113] A: no roller dirt was confirmed B: roller dirt was confirmed YI value For the obtained film, the YI value was measured using a spectrophotometer under light receiving conditions of di: 0° after spectrophotometric illumination in accordance with JIS Z 8722.

[0114] The spectrophotometer used was an SD-7000 manufactured by Nippon Denshoku Industries Co., Ltd.

[0115] [Table 1] Explanation of symbols 1: lens 2: polarizing film 3: polarizing film base material 4: polarizing film base material.

Claims

1. A film, characterized in that: The composition contains 0.3 to 2.9 parts by mass of an ultraviolet absorber having a triazine structure relative to 100 parts by mass of the bisphenol A polycarbonate resin. The thickness of the film is 200 to 600 μm. The average light transmittance of the film at a wavelength of 250 to 400 nm is 3% or less, and the light transmittance of the film at a wavelength of 420 nm is 30% or more.

2. The film according to claim 1, wherein: The ultraviolet absorber contains a compound represented by formula (UV-1), In formula (UV-1), R 1 is a hydrocarbon group having 1 to 10 carbon atoms, or a group consisting of a hydrocarbon group having 1 to 10 carbon atoms and -O- and / or -C(=O)-, R 2 ~R 4 Each independently represents a hydroxyl group, a hydrocarbon group having 1 to 10 carbon atoms, or a group consisting of a hydrocarbon group having 1 to 10 carbon atoms and -O- and / or -C(=O)-, n2 is an integer from 0 to 3, n3 and n4 are each independently an integer of 0 to 4.

3. The film according to claim 2, wherein: The n3 and n4 are each independently an integer of 1 to 4.

4. The film according to claim 1, wherein: The ultraviolet absorber contains a compound represented by formula (UV-2), In formula (UV-2), R 11 and R 31 、R 41 are each independently an aliphatic hydrocarbon group having 3 to 10 carbon atoms, R 2 、R 32 and R 42 Each independently represents a hydroxyl group, a hydrocarbon group having 1 to 10 carbon atoms, or a group consisting of a hydrocarbon group having 1 to 10 carbon atoms and -O- and / or -C(=O)-, n2, n3-1 and n4-1 are each independently an integer of 0 to 3.

5. The film according to claim 1, wherein: The ultraviolet absorber contains a compound represented by formula (UV-3), In formula (UV-3), R 11 and R 31 、R 41 Each independently represents an aliphatic hydrocarbon group having 3 to 10 carbon atoms.

6. The film according to any one of claims 1 to 5, wherein: The film has a light transmittance of 3% or less at a wavelength of 400 nm.

7. The film according to any one of claims 1 to 6, wherein: The difference between the light transmittance of the film at a wavelength of 420 nm and the light transmittance of the film at a wavelength of 400 nm is 35% or more.

8. A polarizing plate, characterized in that: A polarizing film comprising the film according to any one of claims 1 to 7 and a polarizing film.

9. A hot-bend formed body, characterized in that: This is the heat-bent molded body of the polarizing plate according to claim 8.

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