Resin compositions, films, multilayers, and transparent conductive films

Abstract

To provide resin compositions containing polycarbonate resin, which have a low YI value and a small color difference before and after ultraviolet irradiation, as well as resin compositions, films, multilayers, and transparent conductive films. [Solution] A resin composition comprising 100 parts by mass of polycarbonate resin having an end structure represented by formula (1), and 0.7 to 7.0 parts by mass of a polymerized ultraviolet absorber having a molecular weight of 500 to 2000, wherein the YI value when the composition is 50 μm thick is 1.00 or less. In formula (1), R 1 R represents an alkyl group having 8 to 36 carbon atoms, or an alkenyl group having 8 to 30 carbon atoms. 2 Each of these independently represents a halogen atom, an alkyl group with 1 to 20 carbon atoms, or an alkyl group with 6 to 12 carbon atoms. n represents an integer from 0 to 4. TIFF2026048805000025.tif39170

Description

[Technical Field]

[0001] The present invention relates to resin compositions, films, multilayers, and transparent conductive films. [Background technology]

[0002] Polycarbonate resin has been widely used in many fields as an engineering plastic due to its excellent transparency, heat resistance, mechanical properties, and dimensional stability. Furthermore, in recent years, its transparency has led to its use as an optical material in fields such as optical discs, films, and lenses. One example of the use of polycarbonate resin is transparent conductive film. For example, transparent conductive films are used in touch panel film sensors, electronic paper, dye-sensitized solar cells, and other touch sensors. A transparent conductive film 10 is known to consist of, for example, an electrode layer (transparent conductive film) 11, a substrate 12, an adhesive layer 13, and a protective film 14, as shown in Figure 1. Films mainly composed of polycarbonate resin are sometimes used as the substrate and protective film of such transparent conductive films. A specific example of such a transparent conductive film is, for example, the one described in Patent Document 1. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-152187 [Overview of the project] [Problems that the invention aims to solve]

[0004] As mentioned above, polycarbonate resin is used in a variety of applications, and is frequently used in locations exposed to ultraviolet (UV) light. When used in such locations, it is advisable to incorporate UV absorbers to prevent degradation of the polycarbonate resin. Generally, the more UV absorbers added, the better the UV resistance tends to be, but this also tends to cause the resin to yellow. The present invention aims to solve the aforementioned problems and provides a resin composition containing polycarbonate resin, which has a low YI (Yellow index) value, an indicator of yellowness, and a small color difference before and after ultraviolet irradiation, as well as a film, a multilayer, and a transparent conductive film formed from the resin composition. [Means for solving the problem]

[0005] Based on the above problems, the inventors conducted research and found that by using an ultraviolet absorber with a molecular weight within a predetermined range, it is possible to lower the YI value even when a relatively large amount of ultraviolet absorber is incorporated. Specifically, the above problems were solved by the following means. <1> A resin composition comprising 100 parts by mass of polycarbonate resin having an end structure represented by formula (1), and 0.7 to 7.0 parts by mass of an ultraviolet absorber having a molecular weight of 500 to 2000, wherein the YI (Yellow index) value when the composition is 50 μm thick is 1.00 or less. [ka] (In formula (1), R 1 R represents an alkyl group having 8 to 36 carbon atoms, or an alkenyl group having 8 to 30 carbon atoms. 2 Each of these independently represents a halogen atom, an alkyl group with 1 to 20 carbon atoms, or an alkyl group with 6 to 12 carbon atoms. n represents an integer from 0 to 4. * indicates a bonding site with another part. <2> The UV absorber includes a triazine-based UV absorber and / or a cyanoacrylate-based UV absorber. <1> The resin composition described above. <3>The resin composition according to <1> or <2>, wherein the ultraviolet absorber is a multimer. <4>The resin composition according to any one of <1> to <3>, wherein the ultraviolet absorber contains a compound represented by formula (UV1) or formula (UV2). Formula (UV1)

Chemical formula

Chemical formula

[0006] The present invention makes it possible to provide a resin composition containing polycarbonate resin, having a low YI (Yellow Index) value, which is an indicator of yellowness, and a small color difference before and after ultraviolet irradiation, as well as a film, a multilayer, and a transparent conductive film formed from the resin composition. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is an example of a schematic cross-sectional diagram showing the layer structure of a transparent conductive film. [Figure 2] This figure shows a mold used to measure the rate of retardation increase before and after heat molding in the example. [Figure 3] This figure shows how strain is applied to measure chemical resistance in the examples. [Modes for carrying out the invention]

[0008] The following describes in detail embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment"). Note that the following embodiment is illustrative for explaining the present invention, and the present invention is not limited to this embodiment. In this specification, "~" is used to mean that the numbers before and after it are included as the lower and upper limits, respectively. In this specification, all physical properties and characteristic values ​​shall be those at 23°C unless otherwise specified. In this specification, when groups (atomic groups) are not specified as substituted or unsubstituted, the notation includes both groups (atomic groups) with and without substituents. For example, "alkyl group" includes not only unsubstituted alkyl groups but also substituted alkyl groups. In this specification, when notation is not specified as substituted or unsubstituted, unsubstituted is preferred. In this specification, molecular weight (e.g., weight-average molecular weight and number-average molecular weight) is a polystyrene-equivalent value measured by GPC (gel permeation chromatography) unless otherwise specified. In this specification, "film" and "multilayer" each include those in the form of a sheet. "Film" and "sheet" refer to molded articles that are thin in thickness relative to their length and width, and are generally flat. Furthermore, "film" and "sheet" in this specification may be single-layer or multi-layer. If the measurement methods, etc., described in the standards shown herein differ from year to year, unless otherwise specified, the standards as of January 1, 2021 shall apply.

[0009] The resin composition of this embodiment is a resin composition comprising 100 parts by mass of polycarbonate resin having an end structure represented by formula (1), and 0.7 to 7.0 parts by mass of an ultraviolet absorber having a molecular weight of 500 to 2000, characterized in that the YI (Yellow index) value when the thickness is 50 μm is 1.00 or less. [ka] (In formula (1), R 1 represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms. Each R 2 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 from 0 to 4. * represents a bonding site with another site.) By adopting such a configuration, a resin composition with a low YI (Yellow index) value, which is an index indicating yellowness, and a small color difference before and after ultraviolet irradiation can be obtained. Furthermore, even when a large amount of ultraviolet absorber is blended, gas generation during extrusion, roll fouling, and roll fouling transfer can be effectively suppressed.

[0010] <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.

Chemical formula

[0011] R 1 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 an alkenyl group having 10 or more carbon atoms, more preferably an alkyl group or an alkenyl group having 12 or more carbon atoms, and still more preferably an alkyl group or an alkenyl group having 14 or more carbon atoms. Thereby, the glass transition temperature of the resin can be further lowered, and the thermoformability of the multilayer body can be improved. Also, R 1It is preferably an alkyl group or alkenyl group having 22 or fewer carbon atoms, and more preferably an alkyl group or alkenyl group having 18 or fewer carbon atoms. This tends to improve compatibility with other resins. 1 It is preferable that the alkyl group is an alkyl group. The alkyl group and alkenyl group are preferably linear or branched alkyl or alkenyl groups, and more preferably linear alkyl or alkenyl groups. In this embodiment, R 1 It is particularly preferable that this is a hexadecyl group. Also, R 1 It may be located at the meta, para, or ortho position, but it is preferably located at the meta or para position, and more preferably at the para position.

[0012] R 2 Each of these independently represents a halogen atom, a C1-C20 alkyl group, or a C6-C12 aryl group, 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 between 0 and 4, preferably between 0 and 2, more preferably 0 or 1, and even more preferably 0.

[0013] The terminal structure represented by formula (1) can be added to a polycarbonate resin by using an end-capturing agent such as hexadecyl parahydroxybenzoate. Details thereof can be found in paragraphs 0022 to 0030 of Japanese Patent Application Publication No. 2019-002023, and these contents are incorporated herein by reference. The polycarbonate resin with an end structure represented by formula (1) used in this embodiment may consist of one or more end structures represented by formula (1). In this embodiment, the polycarbonate resin having the end structure represented by formula (1) may not have all end structures represented by formula (1). Typically, 80% or more (preferably 90% or more) of the end structures of the polycarbonate resin used in this embodiment are the end structures represented by formula (1).

[0014] In this embodiment, the polycarbonate resin having the end structure represented by formula (1) is preferably a bisphenol-type polycarbonate resin, and more preferably a bisphenol A-type polycarbonate resin. Furthermore, it is preferable that 50 mol% or more of the bisphenol-type polycarbonate resin has at least one end structure represented by formula (1).

[0015] Bisphenol A type polycarbonate resin may also have other structural units other than carbonate structural units derived from bisphenol A and its derivatives. Examples of dihydroxy compounds constituting such other structural units include aromatic dihydroxy compounds described in paragraph 0014 of Japanese Patent Application Publication No. 2018-154819, the details of which are incorporated herein by reference. In this embodiment, the bisphenol-type polycarbonate resin preferably contains carbonate structural units derived from bisphenol A and its derivatives accounting for 90% or more by mass of all structural units excluding terminal structures, more preferably 95% or more by mass, and even more preferably 97% or more by mass.

[0016] The method for producing bisphenol A type polycarbonate resin is not particularly limited, and any method can be used. Examples include interfacial polymerization, molten transesterification, pyridine method, ring-opening polymerization of cyclic carbonate compounds, and solid-phase transesterification of prepolymers.

[0017] 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 make the film highly resistant to bending, resulting in a film with excellent flexibility. Furthermore, a viscosity-average molecular weight of 40,000 or less tends to effectively lower the glass transition temperature of the film, effectively suppressing the rise 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, setting it to 30,000 or more tends to further improve flexural resistance. Furthermore, the viscosity-average molecular weight of the polycarbonate resin is more preferably 38,000 or less, even more preferably 35,000 or less, particularly less than 30,000, and even more particularly 28,000 or less. In particular, setting the viscosity-average molecular weight to less than 30,000, and even more preferably 28,000 or less, tends to lower the viscosity of the polycarbonate resin and improve filter permeability. Improved filter permeability can reduce the amount of foreign matter in the film. The viscosity-average molecular weight is measured according to the description in the examples below.

[0018] The glass transition temperature (Tg) of the polycarbonate resin having the end 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. Setting it below the upper limit tends to further improve the heat-bending moldability of the multilayer body. Furthermore, the glass transition temperature (Tg) of the polycarbonate resin having the end 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. Setting it above the lower limit tends to further improve the durability in environmental resistance tests such as humid heat tests and high-temperature tests. The glass transition temperature (Tg) is measured according to the description in the examples below.

[0019] Further details regarding polycarbonate resin can be found in paragraphs 0040-0073 of Japanese Patent Publication No. 2019-035001 and paragraphs 0016-0043 of Japanese Patent Publication No. 2018-103518, the contents of which are incorporated herein by reference.

[0020] The proportion of polycarbonate resin having the end structure represented by formula (1) in the film of this embodiment is preferably 90% by mass or more, more preferably 92% by mass or more, and even more preferably 94% by mass or more. By setting it above the lower limit, a film with superior transparency can be obtained. The upper limit of the proportion of polycarbonate resin in the film of the above embodiment is preferably 99% by mass or less. The film of this embodiment may contain only one type of polycarbonate resin, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0021] <UV absorber> The resin composition of this embodiment contains 0.7 to 7.0 parts by mass of an ultraviolet absorber with a molecular weight of 500 to 2000 per 100 parts by mass of a polycarbonate resin having an end structure represented by formula (1). With this configuration, a resin composition containing a polycarbonate resin with a low YI (Yellow index) value and exhibiting a small color difference before and after ultraviolet irradiation can be obtained. The molecular weight of the ultraviolet absorber, which has 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. Setting it above the lower limit effectively suppresses the generation of gas and roll contamination during film molding. Furthermore, the molecular weight of the ultraviolet absorber, which has 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. Setting it below the upper limit tends to improve compatibility with the resin. The resin composition of this embodiment may contain only one type of ultraviolet absorber, or it may contain two or more types. When it contains two or more types, it is preferable that at least one of the ultraviolet absorbers contained in the resin composition is an ultraviolet absorber with a value of 500 to 2000, and at least one of the other ultraviolet absorbers is within the above preferred range.

[0022] Examples of UV absorbers used in this embodiment include triazine-based UV absorbers, cyanoacrylate-based UV absorbers, benzotriazole-based UV absorbers, and benzophenone-based UV absorbers, with the inclusion of a triazine-based UV absorber and / or a cyanoacrylate-based UV absorber being preferred. By using a triazine-based UV absorber and / or a cyanoacrylate-based UV absorber, the occurrence of fouling on the rolls during molding can be effectively suppressed. The ultraviolet absorber used in this embodiment is preferably a polymer. A polymer is an ultraviolet absorber that has multiple ultraviolet absorbing sites in a single molecule. Here, the ultraviolet absorbing sites are non-conjugated. Furthermore, it is preferable that the ultraviolet absorbing sites are a single site formed by combining aromatic rings and parts where single bonds are alternately connected to double bonds, triple bonds, etc.

[0023] In this embodiment, the ultraviolet absorber used is preferably one represented by formula (UV1) or formula (UV2). Formula (UV1) [ka] (In equation (UV1), R is an independent substituent, n is an independent integer from 0 to 5, and L 1 is a divalent linking group, n1 is an integer from 2 to 5, and L 11 (This 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) (however, it may contain one or more oxygen atoms or ester groups), a halogen atom (preferably a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, more preferably a fluorine atom or a 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 in the terminal or 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 between 0 and 4, more preferably an integer between 0 and 3, even more preferably an integer between 0 and 2, even more preferably an integer of 0 or 1, and may be 0. L 1 The group is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms, or a group consisting of a combination of a divalent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms and an oxygen atom and / or an ester group. The divalent aliphatic saturated hydrocarbon group is preferably an alkylene group. L 11 The linking group is either a single bond or an n1-valent linking group, with an n1-valent linking group being preferred. The n1-valent linking group is preferably an n1-valent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms, or a group consisting of a combination of an n1-valent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms and an oxygen atom and / or an ester group. n1 is preferably an integer between 2 and 4, more preferably an integer between 3 and 4, and even more preferably 4. In equation (UV1), the n1 structures within the parentheses may be different or identical. Preferably, they are identical. An example of an ultraviolet absorber represented by formula (UV1) is Uvinul 3030FF, manufactured by BASF.

[0024] Formula (UV2) [ka] (In equation (UV2), R is an independent substituent, n is an independent integer from 0 to 5, and L 2 is a divalent linking group, n2 is an integer from 2 to 5, and L 22 (This is a single bond or an n2-valent linking group.) R and n are synonymous with R in equation (UV1), and the preferred range is also the same. L 2 The group is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms, or a group consisting of a combination of a divalent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms and an oxygen atom and / or an ester group. The divalent aliphatic saturated hydrocarbon group is preferably an alkylene group. L 22 The linking group is either a single bond or an n2-valent linking group, with an n2-valent linking group being preferred. The n2-valent linking group is preferably an n2-valent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms, or a group consisting of a combination of an n2-valent aliphatic saturated hydrocarbon group having 1 to 30 carbon atoms and an oxygen atom and / or an ester group. n2 is preferably an integer between 2 and 4, more preferably an integer between 2 and 3, and even more preferably 2. In equation (UV2), the n2 structures within the parentheses may be different or identical. Preferably, they are identical. An example of an ultraviolet absorber represented by formula (UV2) is LA-1000, manufactured by ADEKA Corporation.

[0025] In addition to the ultraviolet absorbers described in the examples below, LA-31 (manufactured by ADEKA) and Tinuvin 360 (manufactured by BASF) are also preferably used in this embodiment.

[0026] 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 even more preferably 2.5 parts by mass or more, and depending on the application, it may be 4.0 parts by mass or more, or 4.5 parts by mass or more. Setting it above the lower limit tends to further improve weather resistance. 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, depending on the application, it 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. By keeping it below the above upper limit, the YI value tends to be low, and the generation of gas and roll fouling can be suppressed more effectively. The resin composition of this embodiment may contain only one UV absorber having a molecular weight of 500 to 2000, or it may contain two or more UV absorbers. When two or more UV absorbers are included, it is preferable that the total amount is within the above range.

[0027] The resin composition of this embodiment may or may not contain ultraviolet absorbers with a molecular weight of less than 500 and ultraviolet absorbers with a molecular weight of more than 2000. Preferably, the resin composition of this embodiment is substantially free of ultraviolet absorbers with a molecular weight of less than 500 and ultraviolet absorbers with a molecular weight of more than 2000. Specifically, the content of ultraviolet absorbers with a molecular weight of less than 500 and ultraviolet absorbers with a molecular weight of more than 2000 is preferably 10% by mass or less, 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, of the content of ultraviolet absorbers with a molecular weight of 500 to 2000.

[0028] <Other ingredients> The film of this embodiment may contain, in addition to the polycarbonate resin having the end structure represented by formula (1), other components as long as it does not depart from the spirit of the present invention. Specifically, it may contain thermoplastic resins other than the polycarbonate resin having the end structure represented by formula (1), antioxidants, transesterification inhibitors, mold release agents, heat stabilizers, flame retardants, flame retardant additives, ultraviolet absorbers, colorants, antistatic agents, fluorescent whitening agents, antifogging agents, flow modifiers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact modifiers, sliding modifiers, hue modifiers, acid trapping agents, etc. One of these components may be used, or two or more may be used in combination. These details can be found in Japanese Patent Publication No. 2017-031313, International Publication No. 2015 / 190162, Japanese Patent Publication No. 2019-002023, and Japanese Patent Publication No. 2018-199745, the contents of which are incorporated herein by reference. The total amount of the other components mentioned above, if present, is preferably 0.001 to 5% by mass of the resin composition, more preferably 0.001 to 2% by mass, and even more preferably 0.01 to 1% by mass.

[0029] The type of mold release agent used in the resin composition of this embodiment is not particularly specified, but examples include aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds with a number average molecular weight of 200 to 15,000, polyethers with a number average molecular weight of 100 to 5,000, and polysiloxane-based silicone oils. Details of the release agent can be found in paragraphs 0035-0039 of International Publication No. 2015 / 190162, which are incorporated herein by reference. The release agent content 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, per 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 this embodiment may use only one type of release agent, or it may use two or more types. When using two or more types, it is preferable that the total amount is within the above range.

[0030] The resin composition of this embodiment is prepared so that the total of a polycarbonate resin having an end structure represented by formula (1), an ultraviolet absorber with a molecular weight of 500 to 2000, and other components added as needed amounts to 100% by mass.

[0031] <Method for producing resin compositions> The method for producing the resin composition of this embodiment is not limited, and a wide range of known production methods can be employed. A specific example of this method involves pre-mixing a predetermined polycarbonate resin, a predetermined ultraviolet absorber, and other components as needed using various mixers such as tumblers, Henschel mixers, and super mixers, and then melt-kneading them using mixers such as Banbury mixers, rolls, brabenders, single-screw extruders, twin-screw extruders, and kneaders.

[0032] <Physical properties of resin compositions> The resin composition of this embodiment preferably has a low YI (Yellow Index). Specifically, the YI value of the resin composition of this embodiment is 1.00 or less when the resin composition is 50 μm thick. Such a low YI value can be achieved, for example, by using an ultraviolet absorber with limited conjugation of ultraviolet absorption sites. For example, a polymeric ultraviolet absorber is a good example. It can also 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, may be 0.90 or less, may be 0.86 or less, or may be 0.80 or less. The lower limit of the YI value is usually ideally 0, practically 0.01 or more, and even 0.1 or more sufficiently satisfies the required performance. In addition, if a blue coloring agent such as a bluing agent is included, the YI value may be less than 0, in which case the lower limit is preferably -2 or more, and more preferably -1 or more. The YI value is measured according to the example described below.

[0033] The resin composition of this embodiment is formed into a film with 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 also be 0.30 or less, 0.25 or less, or even 0.20. Such low color difference can be achieved, for example, by using a broadly conjugated ultraviolet absorber or by increasing the content of the ultraviolet absorber. Ideally, the lower limit of the color difference (ΔE) should be 0, but even if it is 0.01 or higher, it will still sufficiently meet the required performance. The aforementioned color difference (ΔE) is measured according to the description in the examples below.

[0034] The viscosity-average molecular weight of the resin composition in this embodiment is preferably 14,000 to 40,000. A viscosity-average molecular weight of 14,000 or higher makes the resulting film highly resistant to bending, resulting in a film with excellent flexural resistance. Furthermore, a viscosity-average molecular weight of 40,000 or lower tends to effectively lower the glass transition temperature of the film, effectively suppressing the rise 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, setting it to 25,000 or more tends to further improve the flexibility 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 less than 23,000. In particular, setting the viscosity-average molecular weight to less than 25,000, and even more particularly less than 23,000, tends to lower the viscosity of the polycarbonate resin and improve filter permeability. Improved filter permeability reduces the amount of foreign matter in the film.

[0035] 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 in this 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 below.

[0036] The glass transition temperature (Tg) of the resin composition of this embodiment, as determined by differential scanning calorimetry, is preferably 114 to 138°C. Setting it above the lower limit tends to further improve the flexural resistance of the resulting film. Setting it below the upper limit tends to more effectively suppress the rise in Re during thermal shaping of the resulting film. 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, even more preferably 122°C or higher, and 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 according to the description in the examples below.

[0037] <Physical properties and characteristics of the film> The film of this embodiment is formed from the resin composition of this embodiment. The thickness of the film in this embodiment is preferably 20 to 200 μm. By setting the thickness to 20 μm or more, the tearing 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, the rise in Re during the heat shaping of the film can be effectively suppressed, and the flexibility 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 especially even more preferably 60 μm or less.

[0038] The film of this embodiment preferably has a surface roughness Ra of less than 0.7 μm. By having such a configuration, a film with excellent transparency can be obtained. 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 0.0001 μm or more is practical, and even 0.001 μm or more is sufficient to meet the required performance.

[0039] The film of this embodiment preferably has a retardation (Re) of 25.0 nm or less at a wavelength of 543 nm, 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 it below the above upper limit, rainbow unevenness tends to be suppressed more effectively. The lower limit of the retardation (Re) is ideally 0 nm, but 0.01 nm or more is practical.

[0040] 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 keeping it below the above upper limit, the transparency of the film tends to improve further. The lower limit of the haze of the film is ideally 0%, but 0.001% or more is practical. The above-mentioned Ra, Re, and haze are measured according to the examples described below.

[0041] <Film manufacturing method> The film of this embodiment can be manufactured by known methods, for example, extrusion molding and casting molding are preferred. An example of extrusion molding is a method in which pellets, flakes, or powder of a resin composition containing a predetermined polycarbonate resin, a predetermined ultraviolet absorber, and optionally additives are melted and kneaded in an extruder, then extruded through a T-die or the like, and the resulting semi-molten sheet is cooled and solidified while being pressed between polishing rolls or the like to produce the product. The extruder may be single-screw or twin-screw, and either vented or non-vented can be used.

[0042] Even when the film of this embodiment is a multilayer, it can be manufactured by known methods. For example, a multilayer film can be formed by laminating the film inside the die during melt extrusion using a T-die, or by laminating the film after it has been formed.

[0043] <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 having the film of this embodiment and at least one other layer. The other layer can be a known layer, exemplified by an adhesive layer or a hard coat layer, and it is preferable to include an adhesive layer. Of course, it may also have both an adhesive layer and a hard coat layer. A polyolefin resin layer is an example of an adhesive layer. For the hard coat layer, reference can be given to paragraphs 0045 to 0055 of Japanese Patent Publication No. 2013-020130, paragraphs 0073 to 0076 of Japanese Patent Publication No. 2018-103518, and paragraphs 0062 to 0082 of Japanese Patent Publication No. 2017-213771, and these contents are incorporated herein by reference. The film of this embodiment is preferably used as a protective film or substrate for a transparent conductive film. In particular, it is preferably used as a transparent conductive film having a protective layer, an adhesive layer, a substrate, and an electrode layer in that order, wherein at least one of the substrate and the protective layer (preferably at least the protective layer) is the film of this embodiment. In addition, the above transparent conductive film is preferably used as a transparent conductive film for a film sensor of a touch panel, electronic paper, a dye-sensitized solar cell, a touch sensor, or the like. Furthermore, the film of the present embodiment is preferably used for films for applications that require, even in other cases, a small change rate of retardation before and after thermoforming, excellent flex resistance, and high transparency. For example, it is used as an anti-scattering film.

Examples

[0044] ​​​​​​​​​​​​​​​​​The overlapping solution was separated into an aqueous phase and an organic phase. The organic phase was neutralized with phosphoric acid, and the washing with pure water was repeated until the pH of the washing solution became neutral. The aromatic polycarbonate resin powder (PC-1) was obtained by evaporating and distilling off the organic solvent from this purified aromatic polycarbonate resin solution. 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

[0046] <Synthesis example of PC-2> In the above <Synthesis example of PC-1>, CEPB was 348 g (0.96 mol), and the others were carried out in the same manner. Viscosity average molecular weight: 30,500, Tg: 136 °C

[0047] <Synthesis example of PC-3> In the above <Synthesis example of PC-1>, CEPB was 266 g (0.73 mol), and the others were carried out in the same manner. Viscosity average molecular weight: 37,500, Tg: 142 °C

[0048] <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 the solvent, the intrinsic viscosity [η] (unit: dL / g) at a temperature of 20 °C was determined using an Ubbelohde viscometer, and calculated from the Schnell viscosity formula, that is, η = 1.23×10 -4 Mv 0.83 It was calculated from. The intrinsic viscosity [η] is a value calculated by measuring the specific viscosity [ηsp] at each solution concentration [C] (g / dL) according to the following formula.

Equation

[0050] <UV absorbers (triazine-based UV absorbers)> (B1) Tinuvin 1600, manufactured by BASF, molecular weight: 606, structural formula is shown below. [ka] (B2) LA-1000, manufactured by ADEKA, molecular weight: 1000, structural formula is shown below. [ka] (B3) Tinuvin 1577, manufactured by BASF, molecular weight: 426, structural formula is shown below. [ka] (B4) Cyasorb UV-1164, Sun Chemical Co., Ltd., Molecular weight: 510, Structural formula is shown below. [ka] (B5) LA-F70, manufactured by ADEKA Corporation, molecular weight: 700, structural formula is shown below. [ka]

[0051] <UV absorbers (cyanoacrylate-based UV absorbers)> (B6) Uvinul3030FF, manufactured by BASF, molecular weight: 1061, structural formula is shown below. [ka] (B7) Uvinul3035, manufactured by BASF, molecular weight: 277, structural formula is shown below. [ka] (B8) Uvinul3039, manufactured by BASF, molecular weight: 361, structural formula is shown below. [ka]

[0052] <Release agent> (C) Glycerin monostearate, manufactured by Riken Vitamin Co., Ltd., Rikemar S-100A

[0053] 2. Examples 1-1 to 1-8, Comparative Examples 1-1 to 1-14 <Manufacturing of resin compositions (pellets)> Each component shown in Tables 1-3 was weighed to the amount indicated in the table (each component in Tables 1-3 is shown as a mass ratio). After mixing in a tumbler for 15 minutes, the mixture was melt-kneaded at a cylinder temperature of 270°C using a twin-screw extruder with a screw diameter of 32 mm and a vent (TEX30α, manufactured by Japan Steel Works, Ltd.), and pellets were obtained by strand cutting.

[0054] <Film Manufacturing 1> Using the above pellets, a film was manufactured using the following method. The pellets obtained as described above were extruded in a molten state using a T-die melt extruder consisting of a twin-screw extruder with a barrel inner diameter of 25 mm and a screw L / D ratio of 30 (Toyo Seiki Co., Ltd., "Laboplast Mill"), at a discharge rate of 4 kg / h and a screw rotation speed of 60 rpm. After being compressed between the first and second rolls, the pellets were cooled and solidified to produce a film. The cylinder and T-die temperatures were set to 280°C. The final film thickness (in μm) was adjusted by changing the roll speeds of the first and second rolls to achieve the values ​​shown in Tables 1 to 3. Details of the first and second rolls used are as follows: • First roll: Metal mirror-finish roll manufactured by Toyo Seiki Co., Ltd. Dimensions: Outer diameter 100mm x Width 200mm Roll temperature: 100~120℃ • Second roll: Metal mirror-finish roll manufactured by Toyo Seiki Co., Ltd. Dimensions: Outer diameter 100mm x Width 200mm Roll temperature: 100~120℃

[0055] <Presence or absence of gas generation during extrusion> The presence or absence of gas generation during extrusion from the extruder in the above-mentioned <Film Manufacturing 1> was checked. The evaluation was conducted by five experts, and the decision was made by majority vote. A: No gas generation was detected. B: Gas generation was detected.

[0056] <Presence or absence of dirt on the roll> The presence or absence of dirt on the rolls during the above <Film Manufacturing 1> was checked. A: No roll soiling was observed. B: Roller soiling was observed.

[0057] <Presence or absence of roll stain transfer> During the extrusion process described in <Film Manufacturing 1> above, the presence or absence of dirt from the roll being transferred to the film was visually checked. The evaluation was conducted by five experts, and the decision was made by majority vote. A: No evidence was found that the roll stains had been transferred to the film. B: It was found that dirt on the roll had been transferred to the film.

[0058] <Initial color (YI)> The initial YI value of the film obtained in <Film Manufacturing 1> above was measured using a colorimeter in accordance with JIS Z 8781-4:2013 and JIS K 7373:2006. A colorimeter used was the SD7000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

[0059] <ΔE> The film obtained in <Film Manufacturing 1> above was measured using a colorimeter in accordance with JIS Z 8781-4:2013 and JIS K 7373:2006 to determine the L1, a1, and b1 values ​​of the film. Subsequently, a weather resistance test was conducted for 100 hours in accordance with JIS D 0205. After that, the L2, a2, and b2 values ​​of the film after the weather resistance test were measured using a colorimeter. From these, the ΔE value was calculated using the following formula. ΔE=((L2-L1) 2 +(a2-a1) 2 +(b2-b1) 2 )) 1 / 2 A Sunshine Weather Meter S-300 was used for the measurements. A colorimeter SD7000 (manufactured by Nippon Denshoku Industries Co., Ltd.) was used.

[0060] [Table 1]

[0061] [Table 2]

[0062] [Table 3]

[0063] 3. Examples 2-1 to 2-5 <Manufacturing of resin compositions (pellets)> Polycarbonate resin and UV absorber (B2, LA-1000, manufactured by ADEKA Corporation) shown in Table 4 (each component in Table 4 is shown as a mass ratio) were weighed to the amounts shown in Table 4. After mixing in a tumbler for 15 minutes, the mixture was melt-kneaded at a cylinder temperature of 270°C using a twin-screw extruder with a screw diameter of 32 mm and a vent (TEX30α, manufactured by Japan Steel Works, Ltd.), and pellets were obtained by strand cutting. The viscosity-average molecular weight (Mv) and glass transition temperature (Tg) of the obtained resin composition (pellets) were measured according to the method described above.

[0064] <Filter permeability> When manufacturing the above pellets, a polymer filter with a mesh size of 20 μm was attached to a twin-screw extruder with a vent. If the pressure during extrusion exceeded the upper limit and extrusion was not possible, it was designated as B; if extrusion was possible, it was designated as A.

[0065] <Film Manufacturing 2> Using the pellets obtained above, a film was manufactured using the following method. The pellets obtained as described above were extruded in a molten state using a T-die melt extruder consisting of a vented twin-screw extruder (manufactured by Japan Steel Works, "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. After being compressed between the first and second rolls, the pellets were cooled and solidified to produce a film. The cylinder and T-die temperatures were set to 270°C. The final film thickness (in μm) was adjusted by changing the roll speeds of the first and second rolls to achieve the values ​​shown in Table 4. Details of the first and second rolls 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℃ • Second roll: Mirror-finish metal rigid roll (Surface: Hard chrome treatment) Core dimensions: Outer diameter 250mm x width 600mm Roll temperature: 120℃

[0066] <Surface roughness (Ra)> The arithmetic mean surface roughness Ra of the film obtained in <Film Manufacturing 2> above 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 in contact with the second roll, and the average value was calculated. The unit is expressed in μm. The measuring device used was the Mitutoyo Surftest SJ-210.

[0067] <Lettering (Re)> The film obtained in <Film Manufacturing 2> above was cut to a size of 50 × 150 mm, and the retardation at a measurement wavelength of 543 nm was measured. The unit is given in nm. Retardation measurements were performed using a WPA-100 from Photonic Lattice.

[0068] <Increase in retardation before and after heat conditioning (ΔRe)> The film obtained in <Film Manufacturing 2> above was cut to a size of 50 × 150 mm, and the retardation at a measurement wavelength of 543 nm was measured. Line analysis was performed on the measurement results at a length of 100 mm in the longitudinal direction from 25 mm from the short side edge of the film and 25 mm from the long side edge of the film, and the maximum value was taken as the maximum retardation before heat forming. The upper die 21 and lower die 22 shown in Figure 2 were attached to a hydraulic jack-type press machine. The dies were heated to 130°C, the film after retardation measurement was placed on top of the dies, and held for 1 minute with a gap of 1 mm between the upper and lower dies, and heat forming was performed under the conditions of a pressure of 0.5 MPa and a pressurization time of 1 minute. After removing the film and allowing it to cool to 23°C, the retardation was measured in the same way as before heat forming to determine the maximum retardation after heat forming, and the retardation increase rate (unit: %) before and after heat forming was calculated using the following formula. Retardation increase rate = [(Maximum retardation after heat conditioning - Maximum retardation before heat conditioning) / Maximum retardation before heat conditioning] × 100 Retardation was measured using a WPA-100 from Photonic Lattice. A: 50% or less B: More than 50% and less than 120% C: Over 120%

[0069] <Chemical resistance> The pellets obtained above were dried at 110°C for 5 hours in a hot air circulating dryer. Subsequently, 3mm ISO multipurpose test specimens (JIS-K7139 Type A1 with a thickness changed from 4mm to 3mm) were molded using an injection molding machine under the following conditions: cylinder temperature 280°C, mold temperature 80°C, and molding cycle of 45 seconds. A Sodick "PE-100" (product name) injection molding machine was used. The obtained test specimens were annealed in an oven at 110°C for 2 hours. As shown in Figure 3, 2,2-bis(4-glycidyloxyphenyl)propane was applied to the annealed test specimens under a strain of 0.45%, and the specimens were held in an oven at 75°C for 3 hours, after which they were cooled to 23°C. In Figure 3, 31 represents the test specimen, and L represents the distance between the supports. The strain [ε] (%) was calculated using the following formula, with respect to the deflection [s] (mm) of the test specimen, the thickness [h] (mm) of the test specimen, and the distance between supports [L] (mm). ε = 600sh / L 2 The deflection of the test specimen [s] (mm) was calculated using I0 (mm) and I (mm) shown in Figure 3, using the following formula. s = I0 - I The test samples were visually evaluated according to the following criteria. The evaluation was conducted by five experts and the final decision was made by majority vote. A: Chemical scratches occur on the coated surface, but the test specimen does not break. B: The test specimen fractured.

[0070] <Bending resistance> The film obtained in <Film Manufacturing 2> above was cut to 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 bent surface. In this bending resistance test, the test samples after 2000 bending cycles were visually evaluated according to the following criteria. The evaluation was conducted by five experts and decided by majority vote. For the FPC bending test, we used the "No.306 FPC Bending Tester" (product name) manufactured by Yasuda Seiki Seisakusho Co., Ltd. S: No deformation or cracking occurs in the film. A: The film deforms slightly into an arc shape, but no cracks occur. B: The film deforms into an arc shape, but no cracks occur. C: The film deformed into an arc shape, cracks appeared, etc.

[0071] <Hayes[%]> For the film obtained in <Film Manufacturing 2> above, the haze (unit: %) was measured using a haze meter under the condition of a D65 light source and a 10° field of view. A haze meter, model "HM-150" manufactured by Murakami Color Technology Research Institute, was used.

[0072] <Presence or absence of gas generation during extrusion> The presence or absence of gas generation during extrusion from the extruder in the above-mentioned <Film Manufacturing 2> was checked. The evaluation was conducted by five experts, and the decision was made by majority vote. A: No gas generation was detected. B: Gas generation was detected.

[0073] <Presence or absence of dirt on the roll> We checked for any dirt on the rolls during the above <Film Manufacturing 2> process. A: No roll soiling was observed. B: Roller soiling was observed.

[0074] <Presence or absence of roll stain transfer> During the extrusion process described in <Film Manufacturing 2> above, the presence or absence of dirt from the roll being transferred to the film was visually checked. The evaluation was conducted by five experts, and the decision was made by majority vote. A: No evidence was found that the roll stains had been transferred to the film. B: It was found that dirt on the roll had been transferred to the film.

[0075] <Initial color (YI)> The initial YI values ​​of the films obtained in the above <Film Manufacturing 2> were measured using a colorimeter in accordance with JIS Z 8781-4:2013 and JIS K 7373:2006. A colorimeter used was the SD7000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

[0076] <ΔE> The film obtained in <Film Manufacturing 2> above was measured using a colorimeter in accordance with JIS Z 8781-4:2013 and JIS K 7373:2006 to determine the L1, a1, and b1 values ​​of the film. Subsequently, a weather resistance test was conducted for 100 hours in accordance with JIS D 0205. After that, the L2, a2, and b2 values ​​of the film after the weather resistance test were measured using a colorimeter. From these, the ΔE value was calculated using the following formula. ΔE=((L2-L1) 2 +(a2-a1) 2 +(b2-b1) 2 )) 1 / 2 A Sunshine Weather Meter S-300 was used for the measurements. A colorimeter SD7000 (manufactured by Nippon Denshoku Industries Co., Ltd.) was used.

[0077] [Table 4] [Explanation of symbols]

[0078] 10 Transparent conductive film 11 Electrode layer (transparent conductive film) 12 Base material 13 Adhesive layer 14 Protective film 21 Upper mold 22 Lower mold 31 Test specimens

Claims

1. A resin composition comprising 100 parts by mass of polycarbonate resin having an end structure represented by formula (1), and 0.7 to 7.0 parts by mass of an ultraviolet absorber having a molecular weight of 500 to 2000, wherein the YI (Yellow index) value when the composition is 50 μm thick is 1.00 or less. A resin composition comprising a UV absorber represented by formula (UV1) or formula (UV2). 【Chemistry 1】 (In formula (1), R １ R represents an alkyl group having 8 to 36 carbon atoms, or an alkenyl group having 8 to 30 carbon atoms. ２ Each of these independently represents a halogen atom, an alkyl group with 1 to 20 carbon atoms, or an alkyl group with 6 to 12 carbon atoms. n represents an integer from 0 to 4. * indicates a bonding site with another part. Formula (UV1) 【Chemistry 2】 (In formula (UV1), R is an independent substituent, n is an independent integer from 0 to 5, and L １ is a divalent linking group, n1 is an integer from 2 to 5, L １１ (This is a single bond or an n1-valent linking group.) Formula (UV2) 【Transformation 3】 (In formula (UV2), R is an independent substituent, n is an independent integer from 0 to 5, and L ２ is a divalent linking group, n2 is an integer from 2 to 5, and L ２２ (This is a single bond or an n2-valent linking group.)

2. The resin composition according to claim 1, wherein the viscosity-average molecular weight of the resin composition is 14,000 to 40,000.

3. The resin composition according to claim 1, wherein the viscosity-average molecular weight of the resin composition is 25,000 to 40,000.

4. 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.

5. The resin composition according to any one of claims 1 to 4, wherein the glass transition temperature (Tg) of the resin composition, as determined by differential scanning calorimetry, is 114 to 138°C.

6. A film formed from the resin composition according to any one of claims 1 to 5.

7. The film according to claim 6, wherein the thickness of the film is 20 to 200 μm.

8. The film according to claim 6 or 7, wherein the surface roughness Ra of the film is less than 0.7 μm.

9. The film according to claim 6 or 7, wherein the surface roughness Ra of the film is 0.1 μm or less.

10. A film according to any one of claims 6 to 9, wherein the haze is 10% or less.

11. 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.

12. A single-layer film, as described in any one of claims 6 to 11.

13. A multilayer having a film according to any one of claims 6 to 12 and at least one other layer.

14. The multilayer according to claim 13, wherein the other layer includes an adhesive layer.

15. A protective layer, Adhesive layer, Substrate and A transparent conductive film having an electrode layer in this order, A transparent conductive film in which at least one of the substrate and the protective layer is the film described in any one of claims 6 to 12.

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