JP7820156B2 - Resin composition, film, multilayer body, and transparent conductive film - Google Patents

Description

The present invention relates to a resin composition, a film, a multilayer body, and a transparent conductive film.

Polycarbonate resins have been widely used in many fields as engineering plastics due to their excellent transparency, heat resistance, mechanical properties, and dimensional stability. Furthermore, in recent years, their transparency has led to their expanded use as optical materials in fields such as optical disks, films, and lenses.
One example of the use of polycarbonate resin is a transparent conductive film.
For example, transparent conductive films are used in film sensors of touch panels, electronic paper, dye-sensitized solar cells, touch sensors, etc. As shown in Fig. 1 , for example, a transparent conductive film 10 is known that is composed of an electrode layer (transparent conductive film) 11, a substrate 12, an adhesive layer 13, and a protective film 14. As the substrate or protective film of such a transparent conductive film, a film containing a polycarbonate resin as a main component may be used.
A specific example of such a transparent conductive film is known from Patent Document 1, for example.

Japanese Patent Application Laid-Open No. 2018-152187

As mentioned above, polycarbonate resins are used in a variety of applications, including many in places where they are exposed to ultraviolet light. When used in places where they are exposed to ultraviolet light, it is considered to incorporate an ultraviolet absorber to prevent deterioration of the polycarbonate resin. In general, the more ultraviolet absorber incorporated, the more the ultraviolet resistance tends to improve, but the resin also tends to become more yellowish.
The present invention aims to solve the above problems, and provides a resin composition containing a polycarbonate resin, which has a low YI (Yellow index) value, which is an index indicating yellowness, and a small color difference before and after ultraviolet irradiation, as well as a film, a multilayer body, and a transparent conductive film formed from the resin composition.

In view of the above-mentioned problems, the present inventors have conducted research and found that by using an ultraviolet absorber having a molecular weight within a predetermined range, it is possible to reduce the YI value even when a relatively large amount of the ultraviolet absorber is blended. Specifically, the above-mentioned problems have been solved by the following means.
<1> A resin composition comprising 0.7 to 7.0 parts by mass of an ultraviolet absorber having a molecular weight of 500 to 2000 relative to 100 parts by mass of a polycarbonate resin having a terminal structure represented by formula (1), wherein the resin composition has a YI (Yellow index) value of 1.00 or less when made into a thickness of 50 μm.
(In formula (1), ^R1 represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms. Each ^R2 independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms or an alkyl group having 6 to 12 carbon atoms. n represents an integer of 0 to 4. * represents a bonding site to another site.)
<2> The resin composition according to <1>, wherein the ultraviolet absorber includes a triazine-based ultraviolet absorber and/or a cyanoacrylate-based ultraviolet absorber.
<3> The resin composition according to <1> or <2>, wherein the ultraviolet absorber is a polymer.
<4> The resin composition according to any one of <1> to <3>, wherein the ultraviolet absorber includes a compound represented by formula (UV1) or formula (UV2).
Formula (UV1)
(In formula (UV1), each R is independently a substituent, each n is independently an integer of 0 to 5, ^L1 is a divalent linking group, n1 is an integer of 2 to 5, and ^L11 is a single bond or an n1-valent linking group.)
Formula (UV2)
(In formula (UV2), each R is independently a substituent, each n is independently an integer of 0 to 5, ^L2 is a divalent linking group, n2 is an integer of 2 to 5, and ^L22 is a single bond or an n-divalent linking group.)
<5> The resin composition according to any one of <1> to <4>, wherein the viscosity average molecular weight of the resin composition is 14,000 to 40,000.
<6> The resin composition according to any one of <1> to <4>, wherein the viscosity average molecular weight of the resin composition is 25,000 to 40,000.
<7> The resin composition according to any one of <1> to <4>, wherein the viscosity average molecular weight of the resin composition is 14,000 or more and less than 25,000.
<8> The resin composition according to any one of <1> to <7>, wherein the glass transition temperature (Tg) of the resin composition according to differential scanning calorimetry is 114 to 138°C.
<9> A film formed from the resin composition according to any one of <1> to <8>.
<10> The film according to <9>, wherein the thickness of the film is 20 to 200 μm.
<11> The film according to <9> or <10>, wherein the surface roughness Ra of the film is less than 0.7 μm.
<12> The film according to <9> or <10>, wherein the surface roughness Ra of the film is 0.1 μm or less.
<13> The film according to any one of <9> to <12>, which has a haze of 10% or less.
<14> The film according to any one of <9> to <13>, wherein the retardation (Re) of the film at a wavelength of 543 nm is 25.0 nm or less.
<15> The film according to any one of <9> to <14>, which is a single-layer film.
<16> A multilayer body having the film according to any one of <9> to <15> and at least one other layer.
<17> The multilayer body according to <16>, wherein the other layer includes an adhesive layer.
<18> A transparent conductive film having a protective layer, an adhesive layer, a substrate, and an electrode layer in this order, wherein at least one of the substrate and the protective layer is the film according to any one of <9> to <15>.

The present invention makes it possible to provide a resin composition containing a polycarbonate resin that has a low YI (Yellow Index) value, an index indicating yellowness, and a small color difference before and after ultraviolet irradiation, as well as a film, multilayer body, and transparent conductive film formed from the resin composition.

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of a transparent conductive film. FIG. 2 is a diagram showing a mold for measuring the rate of increase in retardation before and after thermal shaping in the examples. FIG. 1 is a diagram showing how strain is applied to measure chemical resistance in an example.

Hereinafter, an embodiment of the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment.
In this specification, the word "to" is used to mean that the numerical values before and after it are included as the lower limit and upper limit.
In this specification, various physical properties and characteristic values are those at 23° C. unless otherwise specified.
In the description of groups (atomic groups) in this specification, when a notation does not specify whether they are substituted or unsubstituted, it includes both groups (atomic groups) that have no substituents and groups (atomic groups) that have substituents. For example, the term "alkyl group" includes not only alkyl groups that have no substituents (unsubstituted alkyl groups) but also alkyl groups that have substituents (substituted alkyl groups). In this specification, when a notation does not specify whether they are substituted or unsubstituted, it is preferable to use unsubstituted.
In this specification, unless otherwise specified, molecular weights (for example, weight average molecular weight and number average molecular weight) are values measured by GPC (gel permeation chromatography) in terms of polystyrene.
The terms "film" and "multilayer body" as used herein are intended to include those in the form of a sheet. "Film" and "sheet" refer to a generally flat shaped body that is thin relative to its length and width. Furthermore, the terms "film" and "sheet" as used herein may be either single-layer or multi-layer.
If the measurement methods, etc. described in the standards shown in this specification differ from year to year, they will be based on the standards as of January 1, 2021, unless otherwise stated.

The resin composition of the present embodiment is a resin composition containing 0.7 to 7.0 parts by mass of an ultraviolet absorber having a molecular weight of 500 to 2000 relative to 100 parts by mass of a polycarbonate resin having a terminal structure represented by formula (1), and is characterized in that the YI (Yellow index) value when made into a thickness of 50 μm is 1.00 or less.
(In formula (1), ^R1 represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms. Each ^R2 independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms or an alkyl group having 6 to 12 carbon atoms. n represents an integer of 0 to 4. * represents a bonding site to another site.)
By using this composition, a resin composition can be obtained that has a low YI (Yellow Index) value, which is an index indicating yellowness, and a small color difference before and after UV irradiation. Furthermore, even if a large amount of UV absorber is blended, gas generation during extrusion, roll contamination, and roll contamination transfer can be effectively suppressed.

<Polycarbonate resin having a terminal structure represented by formula (1)>
The resin composition of the present embodiment contains a polycarbonate resin having a terminal structure represented by formula (1). By using a polycarbonate resin having a terminal structure represented by formula (1), the glass transition temperature of the polycarbonate resin can be lowered.
(In formula (1), ^R1 represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms. Each ^R2 independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 12 carbon atoms. n represents an integer of 0 to 4. * represents a bonding site to another site.)

^R1 represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms, preferably an alkyl group or alkenyl group having 10 or more carbon atoms, more preferably an alkyl group or alkenyl group having 12 or more carbon atoms, and even more preferably an alkyl group or alkenyl group having 14 or more carbon atoms. This can further lower the glass transition temperature of the resin and improve the heat bending properties of the multilayer body. Furthermore, ^R1 is preferably an alkyl group or alkenyl group having 22 or less carbon atoms, more preferably an alkyl group or alkenyl group having 18 or less carbon atoms. This tends to improve compatibility with other resins. ^R1 is preferably an alkyl group. The alkyl group and alkenyl group are preferably linear or branched alkyl groups or alkenyl groups, and more preferably linear alkyl groups or alkenyl groups.
In this embodiment, R ¹ is particularly preferably a hexadecyl group.
Furthermore, R ¹ may be located at any of the meta, para, and ortho positions, but is preferably located at the meta or para position, and more preferably at the para position.

^R2 's each independently represent a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and are preferably a fluorine atom, a chlorine atom, a methyl group, an ethyl group, or a phenyl group, and more preferably a fluorine atom, a chlorine atom, or a methyl group.
n represents an integer of 0 to 4, preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0.

The terminal structure represented by formula (1) can be added to a polycarbonate resin by using a terminal blocking agent such as parahydroxybenzoic acid hexadecyl ester. For details, see paragraphs 0022 to 0030 of JP 2019-002023 A, the contents of which are incorporated herein by reference.
The polycarbonate resin having the terminal structure represented by formula (1) used in this embodiment may have one type of terminal structure represented by formula (1), or two or more types of terminal structures represented by formula (1).
In the polycarbonate resin used in the present embodiment having a terminal structure represented by formula (1), not all of the terminal structures may be terminal structures represented by formula (1). Usually, 80% or more (preferably 90% or more) of the terminal structures of the polycarbonate resin used in the present embodiment are terminal structures represented by formula (1).

In this embodiment, the polycarbonate resin having the terminal structure represented by formula (1) is preferably a bisphenol polycarbonate resin, and more preferably a bisphenol A polycarbonate resin. It is also preferable that 50 mol % or more of the bisphenol polycarbonate resin have at least one terminal structure represented by formula (1).

The bisphenol A polycarbonate resin may also have other structural units in addition to the carbonate structural units derived from bisphenol A and its derivatives. Examples of dihydroxy compounds constituting such other structural units include the aromatic dihydroxy compounds described in paragraph 0014 of JP-A-2018-154819, the contents of which are incorporated herein by reference.
In the bisphenol polycarbonate resin of the present embodiment, carbonate structural units derived from bisphenol A and its derivatives preferably account for 90% by mass or more of all structural units excluding terminal structures, more preferably 95% by mass or more, and even more preferably 97% by mass or more.

There are no particular limitations on the method for producing bisphenol A polycarbonate resin, and any method can be used. Examples include interfacial polymerization, melt transesterification, pyridine, ring-opening polymerization of cyclic carbonate compounds, and solid-phase transesterification of prepolymers.

The viscosity-average molecular weight of the polycarbonate resin used in this embodiment is preferably 17,000 to 40,000. A viscosity-average molecular weight of 17,000 or more makes it possible to improve resistance to bending, resulting in a film with excellent flex resistance. Furthermore, a viscosity-average molecular weight of 40,000 or less tends to effectively lower the glass transition temperature of the film, effectively suppressing an increase in Re during thermal shaping.
The viscosity average molecular weight of the polycarbonate resin is more preferably 20,000 or more, even more preferably 22,000 or more, even more preferably 24,000 or more, and may even be 30,000 or more. In particular, a viscosity average molecular weight of 30,000 or more tends to further improve flex resistance. Furthermore, the viscosity average molecular weight of the polycarbonate resin is more preferably 38,000 or less, even 35,000 or less, particularly less than 30,000, and more particularly 28,000 or less. In particular, by adjusting the viscosity average molecular weight to less than 30,000, or even 28,000 or less, the viscosity of the polycarbonate resin decreases, and filter permeability tends to improve. Improved filter permeability can reduce foreign matter in the film.
The viscosity average molecular weight is measured according to the description in the Examples section below.

The glass transition temperature (Tg) of the polycarbonate resin having a terminal structure represented by formula (1) used in this embodiment is preferably 142°C or lower, more preferably 138°C or lower, and even more preferably 132°C or lower. By setting the Tg at or below the upper limit, the hot bending formability of the multilayer body tends to be further improved. Furthermore, the glass transition temperature (Tg) of the polycarbonate resin having a terminal structure represented by formula (1) used in this embodiment is preferably 118°C or higher, more preferably 122°C or higher, and even more preferably 126°C or higher. By setting the Tg at or above the lower limit, the durability in environmental resistance tests such as moist heat tests and high-temperature tests tends to be further improved.
The glass transition temperature (Tg) is measured as described in the Examples section below.

For further details regarding polycarbonate resins, please refer to the descriptions in paragraphs 0040 to 0073 of JP 2019-035001 A and paragraphs 0016 to 0043 of JP 2018-103518 A, the contents of which are incorporated herein by reference.

The proportion of the polycarbonate resin having the terminal structure represented by formula (1) in the film of this embodiment is preferably 90% by mass or more of the film, more preferably 92% by mass or more, and even more preferably 94% by mass or more. By making it equal to or greater than the lower limit, a film with better transparency can be obtained. The upper limit of the proportion of the polycarbonate resin in the film of the embodiment is preferably 99% by mass or less.
The film of the present embodiment may contain only one type of polycarbonate resin, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

<Ultraviolet absorber>
The resin composition of this embodiment contains 0.7 to 7.0 parts by mass of an ultraviolet absorber having a molecular weight of 500 to 2000 relative to 100 parts by mass of a polycarbonate resin having a terminal structure represented by formula (1). By using such a configuration, a resin composition containing a polycarbonate resin with a low YI (Yellow index) value and showing a small color difference before and after ultraviolet irradiation can be obtained.
The molecular weight of the ultraviolet absorber having a molecular weight of 500 to 2000 is preferably 550 or more, more preferably 590 or more, even more preferably 800 or more, even more preferably 900 or more, and even more preferably 950 or more. By setting the molecular weight at or above the lower limit, the generation of gas and roll contamination during film formation can be effectively suppressed. Furthermore, the molecular weight of the ultraviolet absorber having a molecular weight of 500 to 2000 is preferably 1800 or less, more preferably 1600 or less, even more preferably 1400 or less, even more preferably 1200 or less, and even more preferably 1100 or less. By setting the molecular weight at or below the upper limit, compatibility with resins tends to be improved.
The resin composition of this embodiment may contain only one type of ultraviolet absorber, or may contain two or more types. When two or more types are contained, it is preferable that at least one of the ultraviolet absorbers contained in the resin composition has a molecular weight of 500 to 2000, and at least one other ultraviolet absorber has a molecular weight in the above-mentioned preferred range.

Examples of the UV absorber used in this embodiment include a triazine-based UV absorber, a cyanoacrylate-based UV absorber, a benzotriazole-based UV absorber, and a benzophenone-based UV absorber, and it is preferable to include a triazine-based UV absorber and/or a cyanoacrylate-based UV absorber. By using a triazine-based UV absorber and/or a cyanoacrylate-based UV absorber, it is possible to effectively suppress the occurrence of roll contamination during molding.
The ultraviolet absorber used in this embodiment is preferably a polymer. A polymer refers to an ultraviolet absorber having multiple ultraviolet absorbing moieties in one molecule. Here, the ultraviolet absorbing moieties are non-conjugated. Furthermore, it is preferable that the ultraviolet absorbing moiety is a single moiety consisting of an aromatic ring and a double bond, a triple bond, or the like, alternately connected with a single bond.

The ultraviolet absorber used in this embodiment is preferably one represented by formula (UV1) or formula (UV2).
Formula (UV1)
(In formula (UV1), each R is independently a substituent, each n is independently an integer of 0 to 5, ^L1 is a divalent linking group, n1 is an integer of 2 to 5, and ^L11 is a single bond or an n1-valent linking group.)
R is preferably a hydrocarbon group having 1 to 30 carbon atoms (preferably an aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms) (which may contain one or more oxygen atoms or ester groups), a halogen atom (preferably a fluorine atom, chlorine atom, bromine atom, or iodine atom, more preferably a fluorine atom or chlorine atom), or a hydroxyl group. More preferably, R is a linear or branched alkyl group having 1 to 30 carbon atoms, a linear or branched alkyl group having 1 to 30 carbon atoms containing one or more oxygen atoms and/or ester groups at the end or in the chain, or a hydroxyl group. Even more preferably, R is a linear or branched alkyl group having 1 to 30 carbon atoms, a linear or branched alkoxy group having 1 to 30 carbon atoms, or a hydroxyl group. Here, the hydrocarbon group having 1 to 30 carbon atoms (preferably an aliphatic saturated hydrocarbon group) is preferably a hydrocarbon group having 1 to 10 carbon atoms (preferably an aliphatic saturated hydrocarbon group).
n is preferably an integer of 0 to 4, more preferably an integer of 0 to 3, even more preferably an integer of 0 to 2, and even more preferably an integer of 0 or 1, and may be 0.
^L1 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms or a group formed by combining a divalent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms with an oxygen atom and/or an ester group. The divalent aliphatic saturated hydrocarbon group is preferably an alkylene group.
^L11 is a single bond or an n1-valent linking group, preferably an n1-valent linking group. The n1-valent linking group is preferably an n1-valent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms, or a group formed by combining an n1-valent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms with an oxygen atom and/or an ester group.
n1 is preferably an integer of 2 to 4, more preferably an integer of 3 or 4, and even more preferably 4.
In formula (UV1), the n1 structures in parentheses may be different from each other or may be the same, and preferably are the same.
An example of the ultraviolet absorber represented by formula (UV1) is Uvinul 3030FF, manufactured by BASF.

Formula (UV2)
(In formula (UV2), each R is independently a substituent, each n is independently an integer of 0 to 5, ^L2 is a divalent linking group, n2 is an integer of 2 to 5, and ^L22 is a single bond or an n-divalent linking group.)
R and n have the same meanings as R in formula (UV1), and the preferred ranges are also the same.
^L2 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms or a group formed by combining a divalent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms with an oxygen atom and/or an ester group. The divalent aliphatic saturated hydrocarbon group is preferably an alkylene group.
L ²² is a single bond or an n2-valent linking group, preferably an n2-valent linking group. The n2-valent linking group is preferably an n2-valent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms, or a group formed by combining an n2-valent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms with an oxygen atom and/or an ester group.
n2 is preferably an integer of 2 to 4, more preferably an integer of 2 or 3, and even more preferably 2.
In formula (UV2), the n2 structures in parentheses may be different from each other or may be the same, and preferably are the same.
An example of the ultraviolet absorber represented by formula (UV2) is LA-1000 manufactured by ADEKA Corporation.

In addition to the UV absorbers described in the examples below, other preferred UV absorbers used in this embodiment include LA-31 (manufactured by ADEKA Corporation) and Tinuvin 360 (manufactured by BASF Corporation).

The content of the ultraviolet absorber having a molecular weight of 500 to 2000 in the resin composition of this embodiment is 0.7 parts by mass or more, preferably 0.8 parts by mass or more, more preferably 0.9 parts by mass or more, even more preferably 1.5 parts by mass or more, even more preferably 1.8 parts by mass or more, and still more preferably 2.5 parts by mass or more, relative to 100 parts by mass of the polycarbonate resin, and may be 4.0 parts by mass or more, 4.5 parts by mass or more, depending on the application. By making the content equal to or more than the above lower limit, weather resistance tends to be further improved. Furthermore, the content of the ultraviolet absorber having a molecular weight of 500 to 2000 in the resin composition of this embodiment is 7.0 parts by mass or less, preferably 6.8 parts by mass or less, more preferably 6.5 parts by mass or less, even more preferably 6.4 parts by mass or less, even more preferably 6.0 parts by mass or less, and even more preferably 5.5 parts by mass or less, relative to 100 parts by mass of the polycarbonate resin, and may be 4.5 parts by mass or less, 4.0 parts by mass or less, 3.5 parts by mass or less, 2.5 parts by mass or less, or 1.5 parts by mass or less, depending on the application. By setting the content at or below the upper limit, the YI value tends to be low, and the generation of gas and roll contamination tends to be more effectively suppressed.
The resin composition of the present embodiment may contain only one type or two or more types of ultraviolet absorbers having a molecular weight of 500 to 2000. When two or more types are contained, the total amount is preferably in the above range.

The resin composition of this embodiment may or may not contain UV absorbers with a molecular weight of less than 500 and UV absorbers with a molecular weight of more than 2000. It is preferable that the resin composition of this embodiment is substantially free of UV absorbers with a molecular weight of less than 500 and UV absorbers with a molecular weight of more than 2000. Specifically, the content of UV absorbers with a molecular weight of less than 500 and UV absorbers with a molecular weight of more than 2000 is preferably 10% by mass or less of the content of UV absorbers with a molecular weight of 500 to 2000, more preferably 5% by mass or less, even more preferably 1% by mass or less, and even more preferably 0.1% by mass or less.

<Other ingredients>
The film of this embodiment may contain, in addition to the polycarbonate resin having the terminal structure represented by Formula (1), other components within the scope of the present invention. Specifically, the film may contain thermoplastic resins other than the polycarbonate resin having the terminal structure represented by Formula (1), antioxidants, transesterification inhibitors, release agents, heat stabilizers, flame retardants, flame retardant aids, ultraviolet absorbers, colorants, antistatic agents, fluorescent brighteners, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact improvers, sliding improvers, hue improvers, acid trapping agents, etc. These components may be used alone or in combination of two or more. For details, please refer to the descriptions in JP 2017-031313 A, WO 2015/190162 A, JP 2019-002023 A, and JP 2018-199745 A, the contents of which are incorporated herein by reference.
When contained, the total amount of the other components is preferably 0.001 to 5 mass %, more preferably 0.001 to 2 mass %, and even more preferably 0.01 to 1 mass % of the resin composition.

The type of release agent used in the resin composition of the present embodiment is not particularly limited, but examples thereof include aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000, polyethers having a number average molecular weight of 100 to 5,000, and polysiloxane-based silicone oils.
For details of the release agent, please refer to paragraphs 0035 to 0039 of WO 2015/190162, the contents of which are incorporated herein by reference.
The content of the release agent is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, and even more preferably 0.01 parts by mass or more, relative to 100 parts by mass of the resin composition. The upper limit is preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, and even more preferably 0.2 parts by mass or less.
The resin composition of the present embodiment may use only one type of release agent or two or more types. When two or more types are used, the total amount is preferably in the above range.

The resin composition of this embodiment is prepared so that the total amount of a polycarbonate resin having a terminal structure represented by formula (1), an ultraviolet absorber having a molecular weight of 500 to 2000, and other components blended as necessary is 100% by mass.

<Method of producing resin composition>
The method for producing the resin composition of the present embodiment is not limited, and a wide range of known production methods can be employed.
A specific example of such a method is to premix a predetermined polycarbonate resin, a predetermined ultraviolet absorber, and other components that are blended as necessary using various mixers such as a tumbler, a Henschel mixer, or a super mixer, and then melt-knead the mixture using a mixer such as a Banbury mixer, a roll, a Brabender mixer, a single-screw kneading extruder, a twin-screw kneading extruder, or a kneader.

<Physical Properties of Resin Composition>
The resin composition of this embodiment preferably has a low YI. Specifically, the YI (Yellow index) value when the resin composition of this embodiment is applied to a thickness of 50 μm is 1.00 or less. Such a low YI value can be achieved, for example, by using an ultraviolet absorber in which the conjugation of the ultraviolet absorbing moiety is not extensive. For example, a polymeric ultraviolet absorber can be used. Alternatively, the low YI value can be achieved by adjusting the content of the ultraviolet absorber and the content of other additives.
The YI value is preferably 0.99 or less, and may be 0.90 or less, 0.86 or less, or 0.80 or less. The lower limit of the YI value is usually 0, with 0.01 or more being practical, and even 0.1 or more sufficiently meeting the required performance. Furthermore, when a blue colorant such as a bluing agent is contained, the YI value may be less than 0. In this case, the lower limit is preferably, for example, -2 or more, and more preferably -1 or more.
The YI value is measured as described in the Examples section below.

The resin composition of this embodiment is formed into a film having a thickness of 50 μm, and when subjected to a weather resistance test for 100 hours in accordance with JIS D 0205, the color difference (ΔE) is preferably 1.00 or less, more preferably 0.80 or less, even more preferably 0.60 or less, even more preferably 0.50 or less, even more preferably 0.40 or less, and may even be 0.30 or less, 0.25 or less, or 0.20. Such a low color difference can be achieved, for example, by using an ultraviolet absorber with a wide conjugation range or by increasing the content of the ultraviolet absorber. The lower limit of the color difference (ΔE) is ideally 0, but even if it is 0.01 or more, the required performance is sufficiently met.
The color difference (ΔE) is measured according to the description in the examples below.

The viscosity-average molecular weight of the resin composition of this embodiment is preferably 14,000 to 40,000. A viscosity-average molecular weight of 14,000 or more makes it possible to improve the resistance to bending of the resulting film, resulting in a film with excellent flex resistance. Furthermore, a viscosity-average molecular weight of 40,000 or less tends to effectively lower the glass transition temperature of the film, effectively suppressing an increase in Re during thermal shaping of the film.
The viscosity average molecular weight of the polycarbonate resin is preferably 17,000 or more, more preferably 19,000 or more, even more preferably 21,000 or more, and may even be 25,000 or more. In particular, a viscosity average molecular weight of 25,000 or more tends to further improve the flex resistance of the film. Furthermore, the viscosity average molecular weight of the resin composition of this embodiment is preferably 40,000 or less, and may even be 35,000 or less, 30,000 or less, particularly less than 25,000, and more particularly 23,000 or less. In particular, by adjusting the viscosity average molecular weight to less than 25,000, or even 23,000 or less, the viscosity of the polycarbonate resin is reduced, and filter permeability tends to be improved. Improved filter permeability can reduce foreign matter in the film.

A first example of the viscosity average molecular weight of the resin composition of this embodiment is 25,000 to 40,000.
A second example of the viscosity average molecular weight of the resin composition of the present embodiment is 14,000 or more and less than 25,000.
The viscosity average molecular weight is measured according to the description in the Examples section below.

The glass transition temperature (Tg) of the resin composition of this embodiment, as measured by differential scanning calorimetry, is preferably 114 to 138°C. By setting the Tg at or above the lower limit, the flex resistance of the resulting film tends to be further improved. Furthermore, by setting the Tg at or below the upper limit, the increase in Re of the resulting film during thermal shaping tends to be more effectively suppressed. The glass transition temperature (Tg) of the film is preferably 116°C or higher, more preferably 118°C or higher, even more preferably 120°C or higher, and even more preferably 122°C or higher. Depending on the application, it may be 124°C or higher or 130°C or higher. Furthermore, the glass transition temperature of the film is preferably 137°C or lower, more preferably 135°C or lower, even more preferably 133°C or lower, even more preferably 130°C or lower, and even more preferably 128°C or lower.
The glass transition temperature (Tg) is measured as described in the Examples below.

<Film properties and characteristics>
The film of this embodiment is formed from the resin composition of this embodiment.
The thickness of the film of this embodiment is preferably 20 to 200 μm. By setting the thickness to 20 μm or more, breakage of the film is effectively suppressed, and a film with excellent strength tends to be obtained. Furthermore, by setting the thickness to 200 μm or less, an increase in Re during thermal shaping of the film can be effectively suppressed and flex resistance can be further improved. The thickness of the film is preferably 25 μm or more, and more preferably 30 μm or more. Furthermore, the thickness of the film is preferably 180 μm or less, more preferably 160 μm or less, even more preferably 150 μm or less, even more preferably 140 μm or less, even more preferably 100 μm or less, even more preferably 70 μm or less, and particularly preferably 60 μm or less.

The film of this embodiment preferably has a surface roughness Ra of less than 0.7 μm. This configuration results in a film with excellent transparency. The surface roughness is preferably 0.5 μm or less, more preferably 0.1 μm or less, even more preferably 0.08 μm or less, even more preferably 0.05 μm or less, and even more preferably 0.02 μm or less. The lower limit of the surface roughness Ra of the film is ideally 0 μm, but a value of 0.0001 μm or more is practical, and even a value of 0.001 μm or more will fully satisfy the required performance.

The film of this embodiment preferably has a retardation (Re) at a wavelength of 543 nm of 25.0 nm or less, more preferably 15.0 nm or less, even more preferably 11.0 nm or less, even more preferably 9.0 nm or less, even more preferably 8.0 nm or less, even more preferably 5.0 nm or less, even more preferably 3.0 nm or less, and even more preferably 2.7 nm or less, 2.5 nm or less, 2.3 nm or less, or 2.1 nm or less. By setting the retardation at or below the upper limit, rainbow unevenness tends to be more effectively suppressed. The lower limit of the retardation (Re) is ideally 0 nm, but a value of 0.01 nm or more is practical.

The film of this embodiment preferably has a haze of 10% or less, more preferably 5% or less, even more preferably 1% or less, even more preferably 0.5% or less, and even more preferably 0.2% or less. By setting the haze at or below the upper limit, the transparency of the film tends to be further improved. The lower limit of the haze of the film is ideally 0%, but practically 0.001% or more.
The Ra, Re and haze are measured according to the description in the examples below.

<Film manufacturing method>
The film of this embodiment can be produced by a known method, and for example, extrusion molding or cast molding is preferred. Examples of extrusion molding include a method in which pellets, flakes, or powder of a resin composition containing a predetermined polycarbonate resin, a predetermined UV absorber, and, if necessary, additives are melted and kneaded in an extruder, and then extruded through a T-die or the like, and the resulting semi-molten sheet is cooled and solidified while being sandwiched and pressed between polishing rolls or the like to form a product. The extruder may be single-screw or twin-screw, and either vented or non-vented may be used.

When the film of this embodiment is a multilayer body, it can be produced by known methods. For example, during melt extrusion using a T-die, the materials can be laminated inside the die and formed into a film, or the materials can be formed into a film and then laminated to form a multilayer film.

<Application>
The film of this embodiment can be used as a single layer film. Furthermore, as described above, the film of this embodiment can also be used as a multilayer body having the film of this embodiment and at least one other layer. The other layer can be a known layer, such as an adhesive layer or a hard coat layer, and preferably includes an adhesive layer. Of course, the film may have both an adhesive layer and a hard coat layer.
The adhesive layer may be, for example, a polyolefin resin layer.
For the hard coat layer, the descriptions in paragraphs 0045 to 0055 of JP-A-2013-020130, the descriptions in paragraphs 0073 to 0076 of JP-A-2018-103518, and the descriptions in paragraphs 0062 to 0082 of JP-A-2017-213771 can be referred to, and the contents of these can be incorporated into this specification.
The film of the present embodiment is preferably used as a protective film or substrate for a transparent conductive film, particularly as a transparent conductive film having a protective layer, an adhesive layer, a substrate, and an electrode layer in this order, in which at least one of the substrate and the protective layer (preferably at least the protective layer) is the film of the present embodiment.
The transparent conductive film is also preferably used as a transparent conductive film for use in film sensors of touch panels, electronic paper, dye-sensitized solar cells, touch sensors, and the like.
Furthermore, the film of the present embodiment is also preferably used for applications other than those mentioned above, which require a small change in retardation before and after thermal shaping, excellent bending resistance, and high transparency. For example, it is used as a shatterproof film.

The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.
If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

1. Raw materials <Synthesis example of PC-1>
Based on the description in Organic Chemistry Handbook, pp. 143-150, esterification was carried out by dehydration using 4-hydroxybenzoic acid manufactured by Tokyo Chemical Industry Co., Ltd. and 1-hexadecanol manufactured by Tokyo Chemical Industry Co., Ltd. to obtain hexadecyl parahydroxybenzoate (CEPB).
7.1 kg (31.14 mol) of bisphenol A (BPA) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. and 30 g of hydrosulfite were dissolved in 57.2 kg of a 9% by mass aqueous solution of sodium hydroxide. 40 kg of dichloromethane was added thereto, and while stirring, 4.33 kg of phosgene was blown in over 30 minutes while maintaining the solution temperature in the range of 15 to 25°C.
After the completion of the phosgene injection, 6 kg of a 9% by mass aqueous solution of sodium hydroxide, 11 kg of dichloromethane, and a solution in which 443 g (1.22 mol) of CEPB obtained above was dissolved in 10 kg of dichloromethane were added, and the mixture was emulsified by vigorously stirring. Then, 10 ml of triethylamine was added as a polymerization catalyst, and polymerization was carried out for about 40 minutes.
The polymerization solution was separated into an aqueous phase and an organic phase, the organic phase was neutralized with phosphoric acid, and the organic phase was repeatedly washed with pure water until the pH of the washings became neutral. The organic solvent was evaporated and distilled off from this purified aromatic polycarbonate resin solution to obtain an aromatic polycarbonate resin powder (PC-1).
The viscosity average molecular weight (Mv) and glass transition temperature (Tg) of the obtained aromatic polycarbonate resin powder were measured. Viscosity average molecular weight: 25,500, Tg: 130°C

<Synthesis Example of PC-2>
The same procedure was carried out as in the above <Synthesis Example of PC-1>, except that 348 g (0.96 mol) of CEPB was used. Viscosity average molecular weight: 30,500, Tg: 136°C

<Synthesis Example of PC-3>
The same procedure was carried out as in the above <Synthesis Example of PC-1>, except that 266 g (0.73 mol) of CEPB was used. Viscosity average molecular weight: 37,500, Tg: 142°C

<Measurement of viscosity average molecular weight (Mv)>
The viscosity average molecular weight of the polycarbonate resin and the resin composition was measured by the following method.
Using methylene chloride as a solvent, the intrinsic viscosity [η] (unit: dL/g) at a temperature of 20°C was determined using an Ubbelohde viscometer, and calculated from Schnell's viscosity formula, i.e., η = 1.23 × 10 ^-4 Mv ^0.83 . The intrinsic viscosity [η] is a value calculated from the specific viscosity [ηsp] measured at each solution concentration [C] (g/dL) using the following formula:

<Measurement of Glass Transition Temperature (Tg)>
The glass transition temperatures of the polycarbonate resin and the resin composition were measured as follows.
Approximately 10 mg of polycarbonate resin and resin composition (pellets) were subjected to two heating and cooling cycles under the following DSC (differential scanning calorimetry) measurement conditions, and the glass transition temperature during the second heating cycle was measured. The initial glass transition temperature was determined as the point at which a line extending the low-temperature baseline toward the high-temperature side intersects with a tangent to the inflection point, and the final glass transition temperature was determined as the point at which a line extending the high-temperature baseline toward the low-temperature side intersects with a tangent to the inflection point. The midpoint between the initial and final glass transition temperatures was determined as the glass transition temperature (Tg, unit: ° C.) in the present invention.
Measurement start temperature: 30℃
Temperature rise rate: 10°C/min. Final temperature: 250°C
Temperature decreasing rate: 20° C./min. The measurement device used was a differential scanning calorimeter (DSC, manufactured by Hitachi High-Tech Science Corporation, "DSC7020").

<Ultraviolet absorber (triazine-based UV absorber)>
(B1) Tinuvin 1600, manufactured by BASF, molecular weight: 606, structural formula is shown below.
(B2) LA-1000, manufactured by ADEKA Corporation, molecular weight: 1000, structural formula is shown below.
(B3) Tinuvin 1577, manufactured by BASF, molecular weight: 426, structural formula is shown below.
(B4) Cyasorb UV-1164, Sun Chemical Co., Ltd., molecular weight: 510, structural formula is shown below.
(B5) LA-F70, manufactured by ADEKA Corporation, molecular weight: 700, structural formula is shown below.

<Ultraviolet absorber (cyanoacrylate-based UV absorber)>
(B6) Uvinul 3030FF, manufactured by BASF, molecular weight: 1061, structural formula is shown below.
(B7) Uvinul 3035, manufactured by BASF, molecular weight: 277, structural formula is shown below.
(B8) Uvinul 3039, manufactured by BASF, molecular weight: 361, structural formula is shown below.

<Release Agent>
(C) Glycerin monostearate, manufactured by Riken Vitamin Co., Ltd., Rikemal S-100A

2. Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-14
<Production of Resin Composition (Pellets)>
Each component shown in Tables 1 to 3 was weighed out so as to obtain the amount of addition shown in the table (each component in Tables 1 to 3 is shown as a mass ratio). After mixing for 15 minutes in a tumbler, the mixture was melt-kneaded at a cylinder temperature of 270°C in a vented twin-screw extruder ("TEX30α" manufactured by The Japan Steel Works, Ltd.) with a screw diameter of 32 mm, and pellets were obtained by strand cutting.

<Film production 1>
Using the pellets, a film was produced in the following manner.
The pellets obtained above were extruded into a molten state using a T-die melt extruder consisting of a vented twin-screw extruder ("Labo Plastomill" manufactured by Toyo Seiki Seisaku-sho, Ltd.) with a barrel inner diameter of 25 mm and a screw L/D of 30 at a discharge rate of 4 kg/h and a screw rotation speed of 60 rpm. The pellets were pressed between a first roll and a second roll, and then cooled and solidified to produce a film. The cylinder and T-die temperatures were 280°C.
The thickness (unit: μm) of the final film was adjusted by changing the roll speeds of the first roll and the second roll so as to achieve the values shown in Tables 1 to 3.
Details of the first roll and second roll used are as follows.
First roll: Metal mirror finish roll manufactured by Toyo Seiki Co., Ltd. Dimensions: outer diameter 100 mm x width 200 mm
Roll temperature: 100 to 120°C
Second roll: Metal mirror finish roll manufactured by Toyo Seiki Co., Ltd. Dimensions: outer diameter 100 mm x width 200 mm
Roll temperature: 100 to 120°C

<Whether or not gas is generated during extrusion>
The presence or absence of gas generation during extrusion from the extruder in the above <Film Production 1> was confirmed. The evaluation was carried out by five experts and judged by majority vote.
A: No gas generation was observed.
B: Gas generation was observed.

<Whether or not the roll is dirty>
The presence or absence of contamination on the roll during the above <Film Production 1> was confirmed.
A: No contamination of the roll was observed.
B: Roll contamination was observed.

<Whether or not dirt is transferred to the roll>
During the extrusion in the above <Film Production 1>, the presence or absence of transfer of dirt from the roll to the film was visually confirmed. The evaluation was carried out by five experts and judged by majority vote.
A: No transfer of roll dirt to the film was observed.
B: Transfer of roll dirt to the film was observed.

<Initial color (YI)>
The initial YI value of the film obtained in <Film Production 1> above was measured using a color difference meter in accordance with JIS Z 8781-4:2013 and JIS K 7373:2006.
The color difference meter used was SD7000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

<ΔE>
The L1 value, a1 value, and b1 value of the film obtained in <Film Production 1> above were measured using a color difference meter in accordance with JIS Z 8781-4:2013 and JIS K 7373:2006. Thereafter, a weather resistance test was performed for 100 hours in accordance with JIS D 0205. Thereafter, the L2 value, a2 value, and b2 value of the film after the weather resistance test were measured using the color difference meter. From these values, the ΔE value was calculated using the following formula.
ΔE = ((L2-L1) ² + (a2-a1) ² + (b2-b1) ² )) ^1/2
The measurements were carried out using a Sunshine Weather Meter S-300 and a color difference meter SD7000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

3. Examples 2-1 to 2-5
<Production of Resin Composition (Pellets)>
The polycarbonate resin and ultraviolet absorber (B2, LA-1000, manufactured by ADEKA Corporation) shown in Table 4 (each component in Table 4 is shown in mass ratio) were weighed out to obtain the contents shown in Table 4. After mixing for 15 minutes in a tumbler, the mixture was melt-kneaded at a cylinder temperature of 270°C in a vented twin-screw extruder having a screw diameter of 32 mm ("TEX30α" manufactured by The Japan Steel Works, Ltd.), and pellets were obtained by strand cutting.
The viscosity average molecular weight (Mv) and glass transition temperature (Tg) of the resulting resin composition (pellets) were measured according to the above-mentioned methods.

<Filter permeability>
When producing the pellets, a polymer filter with a 20 μm opening was attached to a vented twin-screw extruder, and if the pressure during extrusion exceeded the upper limit and extrusion was not possible, it was rated B, and if extrusion was possible, it was rated A.

<Film production 2>
The pellets obtained above were used to produce a film in the following manner.
The pellets obtained above were extruded into a molten state using a T-die melt extruder consisting of a vented twin-screw extruder (manufactured by The Japan Steel Works, Ltd., "TEX30α") with a barrel diameter of 32 mm and a screw L/D ratio of 31.5 at a discharge rate of 10 kg/h and a screw rotation speed of 150 rpm. The pellets were pressed between a first roll and a second roll, and then cooled and solidified to produce a film. The cylinder and T-die temperatures were 270°C.
The thickness (unit: μm) of the final film was adjusted by changing the roll speeds of the first roll and the second roll so as to obtain the values shown in Table 4.
Details of the first roll and second roll used are as follows.
First roll: Silicone rubber roll (IT68S-MCG) manufactured by Mochida Shoko Co., Ltd.
Dimensions: outer diameter 260mm x width 600mm
Roll temperature: 50°C
・Second roll: mirror-finished rigid metal roll (surface: hard chrome treated)
Core dimensions: outer diameter 250 mm x width 600 mm
Roll temperature: 120°C

<Surface roughness (Ra)>
The arithmetic mean surface roughness Ra of the film obtained in the above <Film Production 2> was measured using a contact surface roughness meter. Specifically, in accordance with JIS B0601:2001, measurements were taken at three points in the width direction on the surface of the film that contacted the second roll, and the average value was calculated. The unit is μm.
The measurement device used was "Surftest SJ-210" manufactured by Mitutoyo Corporation.

<Retardation (Re)>
The film obtained in the above <Film Production 2> was cut into a size of 50 x 150 mm, and the retardation was measured at a measurement wavelength of 543 nm. The unit is shown in nm.
The retardation was measured using a WPA-100 manufactured by Photonic Lattice.

<Retardation increase rate (ΔRe) before and after thermal shaping>
The film obtained in <Film Production 2> above was cut into a size of 50 x 150 mm, and the retardation at a measurement wavelength of 543 nm was measured. The measurement results were analyzed by line analysis over a 100 mm length in the longitudinal direction from positions 25 mm from the short edge of the film and 25 mm from the long edge of the film, and the maximum value was taken as the maximum retardation before thermal shaping. The upper mold 21 and lower mold 22 shown in Figure 2 were attached to a hydraulic jack press. The mold was heated to 130°C, and the film after retardation measurement was placed on the mold and held for 1 minute with a gap of 1 mm between the upper and lower molds. Thermal shaping was performed under conditions of a pressure of 0.5 MPa and a pressure time of 1 minute. The film was removed and allowed to cool to 23°C. The retardation was measured in the same manner as before thermal shaping to determine the maximum retardation after thermal shaping. The retardation increase rate (unit: %) before and after thermal shaping was calculated using the following formula:
Retardation increase rate = [(maximum retardation after thermal shaping - maximum retardation before thermal shaping) / maximum retardation before thermal shaping] x 100
The retardation was measured using a WPA-100 manufactured by Photonic Lattice.
A: 50% or less B: More than 50% and 120% or less C: More than 120%

<Chemical resistance>
The pellets obtained above were dried in a hot air circulation dryer at 110°C for 5 hours, and then molded into 3 mm ISO multipurpose test specimens (JIS-K7139 Type A1 thickness changed from 4 mm to 3 mm) using an injection molding machine under conditions of a cylinder temperature of 280°C, a mold temperature of 80°C, and a molding cycle of 45 seconds.
The injection molding machine used was a "PE-100" (trade name) manufactured by Sodick Corporation. The obtained test specimens were annealed in an oven at 110°C for 2 hours. As shown in Figure 3, the annealed test specimens were coated with 2,2-bis(4-glycidyloxyphenyl)propane as the test substance while being subjected to a strain of 0.45%, and then held in an oven at 75°C for 3 hours, and then cooled to 23°C. In Figure 3, 31 indicates the test specimen, and L indicates the distance between supports.
The strain [ε] (%) was calculated from the following formula using the deflection [s] (mm) of the test piece, the thickness [h] (mm) of the test piece, and the distance between supports [L] (mm).
ε=600sh/L ²
The deflection [s] (mm) of the test piece was calculated from the following formula using I0 (mm) and I (mm) shown in Figure 3.
s = I0 - I
The test samples were visually inspected and evaluated according to the following criteria. The evaluation was carried out by five experts and judged by majority vote.
A: Chemical damage occurs on the coated surface, but the test piece does not break.
B: The test piece broke.

<Bending resistance>
The film obtained in <Film Production 2> above was cut into a size of 75 x 25 mm, and a bending resistance test was performed using an FPC (flexible printed circuit board) bending tester in accordance with JIS C5016:1994, with a bending radius of 4.0 mm on the bending surface. In this bending resistance test, the test sample after 2000 bending cycles was visually evaluated according to the following criteria. The evaluation was performed by five experts using a majority vote.
The FPC bending tester used was "No. 306 FPC bending tester" (product name) manufactured by Yasuda Seiki Seisakusho Co., Ltd.
S: Neither deformation nor cracking of the film occurs.
A: The film is slightly deformed into an arc shape, but no cracks occur.
B: The film is deformed into an arc shape, but no cracks occur.
C: The film was deformed into an arc shape, cracks were generated, etc.

<Haze [%]>
The haze (unit: %) of the film obtained in the above <Film Production 2> was measured using a haze meter under conditions of a D65 light source and a 10° field of view.
The haze meter used was "HM-150" manufactured by Murakami Color Research Laboratory.

<Whether or not gas is generated during extrusion>
The presence or absence of gas generation during extrusion from the extruder in the above <Film Production 2> was confirmed. The evaluation was carried out by five experts and judged by majority vote.
A: No gas generation was observed.
B: Gas generation was observed.

<Whether or not the roll is dirty>
The presence or absence of contamination on the roll during the above <Film Production 2> was confirmed.
A: No contamination of the roll was observed.
B: Roll contamination was observed.

<Whether or not dirt is transferred to the roll>
During the extrusion in the above <Film Production 2>, the presence or absence of transfer of dirt from the roll to the film was visually confirmed. The evaluation was carried out by five experts and judged by majority vote.
A: No transfer of roll dirt to the film was observed.
B: Transfer of roll dirt to the film was observed.

<Initial color (YI)>
The initial YI value of the film obtained in <Film Production 2> above was measured using a color difference meter in accordance with JIS Z 8781-4:2013 and JIS K 7373:2006.
The color difference meter used was SD7000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

<ΔE>
The L1 value, a1 value, and b1 value of the film obtained in <Film Production 2> above were measured using a color difference meter in accordance with JIS Z 8781-4:2013 and JIS K 7373:2006. Thereafter, a weather resistance test was performed for 100 hours in accordance with JIS D 0205. Thereafter, the L2 value, a2 value, and b2 value of the film after the weather resistance test were measured using the color difference meter. From these values, the ΔE value was calculated using the following formula.
ΔE = ((L2-L1) ² + (a2-a1) ² + (b2-b1) ² )) ^1/2
The measurements were carried out using a Sunshine Weather Meter S-300 and a color difference meter SD7000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

10 Transparent conductive film 11 Electrode layer (transparent conductive film)
12 Substrate 13 Adhesive layer 14 Protective film 21 Upper mold 22 Lower mold 31 Test piece

Claims (15)

A resin composition comprising 0.7 to 7.0 parts by mass of an ultraviolet absorber having a molecular weight of 500 to 2000 relative to 100 parts by mass of a polycarbonate resin having a terminal structure represented by formula (1), wherein the resin composition has a YI (Yellow index) value of 1.00 or less when made into a thickness of 50 μm, and the ultraviolet absorber comprises at least one of the following (B1), (B2), and (B6) :
(In formula (1), ^R1 represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms. Each ^R2 independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms or an alkyl group having 6 to 12 carbon atoms. n represents an integer of 0 to 4. * represents a bonding site to another site.)
(B1)
(B2)
(B6)
The resin composition according to claim 1 , wherein the viscosity average molecular weight of the resin composition is 14,000 to 40,000. The resin composition according to claim 1 , wherein the viscosity average molecular weight of the resin composition is 25,000 to 40,000. The resin composition according to claim 1 , wherein the viscosity average molecular weight of the resin composition is 14,000 or more and less than 25,000. The resin composition according to any one of claims 1 to 4 , wherein the resin composition has a glass transition temperature (Tg) of 114 to 138°C according to differential scanning calorimetry. A film formed from the resin composition according to any one of claims 1 to 5 . The film of claim 6 , wherein the thickness of the film is 20 to 200 μm. 8. The film of claim 6 or 7 , wherein the surface roughness Ra of the film is less than 0.7 μm. 8. The film according to claim 6 , wherein the surface roughness Ra of the film is 0.1 μm or less. The film according to any one of claims 6 to 9 , having a haze of 10% or less. The film according to any one of claims 6 to 10 , wherein the retardation (Re) of the film at a wavelength of 543 nm is 25.0 nm or less. The film according to any one of claims 6 to 11 , which is a monolayer film. A multilayer body comprising the film according to any one of claims 6 to 12 and at least one other layer. The multilayer body of claim 13 , wherein the other layer comprises an adhesive layer. A protective layer;
An adhesive layer;
A substrate;
a transparent conductive film having, in this order, a first electrode layer and a second electrode layer,
A transparent conductive film, wherein at least one of the substrate and the protective layer is the film according to any one of claims 6 to 12 .