Films, multilayers and transparent conductive films

Abstract

This invention provides a film, multilayer, and transparent conductive film exhibiting low rate of change in retardation before and after thermal forming, excellent bending resistance, and excellent transparency. The film contains an aromatic polycarbonate resin with the end structure shown in formula (1), wherein the viscosity-average molecular weight of the aromatic polycarbonate resin is 17,000–40,000, the film thickness is 20–150 μm, and the surface roughness Ra of the film is less than 0.7 μm. In formula (1), R... 1 It refers to an alkyl group with 8 to 36 carbon atoms or an alkenyl group with 8 to 30 carbon atoms.

Description

Technical Field

[0001] This invention relates to films, multilayers, and transparent conductive films. Background Technology

[0002] Transparent conductive films are used in membrane sensors for touchscreens, electronic paper, pigment-sensitized solar cells, and touch sensors. For example, transparent conductive film 10... Figure 1 As shown, the transparent conductive film is known to consist of an electrode layer (transparent conductive film) 11, a substrate 12, an adhesive layer 13, and a protective film 14. A specific example of such a transparent conductive film is the film described in Patent Document 1. The substrate and protective film of such transparent conductive films sometimes use films with polycarbonate resin as the main component. Furthermore, films described in Patent Documents 2 and 3 have also been studied as films with polycarbonate resin as the main component.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-152187

[0006] Patent Document 2: International Publication No. 2016 / 060100

[0007] Patent Document 3: Japanese Patent Application Publication No. 2019-002023 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] In the case of using polycarbonate resin-based films as transparent conductive films, depending on the application, a small rate of change in retardation before and after heat forming, as well as good bending resistance, are sometimes required. That is, in the case of curved displays, if the retardation change during heat forming is large, iridescence asymmetry (coloration caused by birefringence) will occur. Furthermore, poor bending resistance sometimes makes it difficult to use in curved or foldable displays. Also, since it is a display, a transparent film is naturally required. Such properties are also required when using polycarbonate resin-based films as anti-scattering films for curved glass.

[0010] The purpose of this invention is to solve the technical problem of having a small rate of change of delay before and after thermal forming, excellent bending resistance, and excellent transparency, as well as multilayers and transparent conductive films containing the above-mentioned films.

[0011] Technical solutions for solving technical problems

[0012] Based on the above-mentioned technical problems, the inventors of this invention conducted research and found that by using an aromatic polycarbonate resin with a specified molecular weight and a specified end structure, and by adjusting the thickness and surface roughness of the film to a specified range, the above-mentioned technical problems can be solved.

[0013] The aforementioned technical problems can be solved through the following solutions.

[0014] <1> A membrane containing an aromatic polycarbonate resin having an end structure as shown in formula (1), wherein the viscosity-average molecular weight of the aromatic polycarbonate resin is 17,000 to 40,000, the thickness of the membrane is 20 to 150 μm, and the surface roughness Ra of the membrane is less than 0.7 μm.

[0015]

[0016] (In equation (1), R) 1 R represents an alkyl group with 8 to 36 carbon atoms or an alkenyl group with 8 to 30 carbon atoms. 2 Each of these groups independently represents a halogen atom, an alkyl group with 1 to 20 carbon atoms, or an aryl group with 6 to 12 carbon atoms; n represents an integer from 0 to 4; and * indicates a bonding site with other sites.

[0017] <2> The membrane as described in <1>, wherein the glass transition temperature of the membrane is 115 to 142°C.

[0018] <3> The membrane as described in <1> or <2>, wherein the viscosity-average molecular weight of the aromatic polycarbonate resin is 30,000 to 40,000.

[0019] <4> The membrane as described in <1> or <2>, wherein the viscosity-average molecular weight of the aromatic polycarbonate resin is 17,000 or more and less than 30,000.

[0020] <5> The membrane as described in any one of <1> to <4>, wherein the surface roughness Ra of the membrane is 0.1 μm or less.

[0021] <6> The membrane as described in any one of <1> to <5>, wherein the haze of the membrane is 10% or less.

[0022] <7> The membrane as described in any one of <1> to <6>, wherein the delay (Re) of the membrane for light with a wavelength of 543 nm is 25 nm or less.

[0023] <8> The membrane as described in any one of <1> to <7> is a single-layer membrane.

[0024] <9> A multilayer body having the membrane described in any one of <1> to <8> and at least one other layer.

[0025] <10> A multilayer body as described in <9>, wherein the other layers mentioned above include an adhesive layer.

[0026] <11> A transparent conductive film having, in sequence, a protective layer, an adhesive layer, a substrate and an electrode layer, wherein at least one of the substrate and the protective layer is the film described in any one of <1> to <8>.

[0027] Invention Effects

[0028] According to the present invention, it is possible to provide a film with a small rate of change of delay before and after thermal forming, excellent bending resistance, and excellent transparency, as well as a multilayer comprising the above-mentioned film and a transparent conductive film. Attached Figure Description

[0029] Figure 1 This is an example of a cross-sectional schematic diagram showing the layered structure of a transparent conductive film.

[0030] Figure 2 This is a diagram showing the mold used to measure the rate of delayed rise before and after heat forming in the embodiment.

[0031] Figure 3 This is a diagram illustrating the method of applying deformation for measuring the drug resistance of the embodiments.

[0032] Symbol Explanation

[0033] 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. Detailed Implementation

[0034] Hereinafter, specific embodiments of the present invention (hereinafter referred to as "this embodiment") will be described in detail. However, the following embodiments are merely examples for illustrating the present invention, and the present invention is not limited to these embodiments.

[0035] In this specification, the use of “~” is intended to include the values ​​described before and after it as the lower and upper limits.

[0036] Unless otherwise specified, all physical property values ​​and characteristic values ​​in this manual refer to the values ​​at 23°C.

[0037] In the designation of groups (atomic groups) in this specification, the absence of markings for substitution and non-substitution includes both unsubstituent groups (atomic groups) and substituent groups (atomic groups). For example, "alkyl" includes not only unsubstituent alkyl groups (unsubstituted alkyl groups) but also substituent alkyl groups (substituted alkyl groups). In this specification, the absence of markings for substitution and non-substitution is preferred, especially the absence of substituent.

[0038] In this specification, multilayer bodies include those forming films or sheets. "Film" and "sheet" refer to molded bodies that are thin relative to their length and width, and are generally flat. Furthermore, "film" in this specification can refer to a single layer or multiple layers.

[0039] In addition, "parts by mass" in this specification refers to the relative amount of the ingredient, and "% by mass" refers to the absolute amount of the ingredient.

[0040] The membrane of this embodiment is characterized in that it is a membrane containing an aromatic polycarbonate resin having an end structure as shown in formula (1), wherein the viscosity-average molecular weight of the aromatic polycarbonate resin is 17,000 to 40,000, the thickness of the membrane is 20 to 150 μm, and the surface roughness Ra of the membrane is less than 0.7 μm.

[0041]

[0042] (In equation (1), R) 1 Represents an alkyl group with 8 to 36 carbon atoms or an alkenyl group with 8 to 30 carbon atoms. R 2 Each of these groups independently represents a halogen atom, an alkyl group with 1 to 20 carbon atoms, or an aryl group with 6 to 12 carbon atoms. n represents an integer from 0 to 4. * indicates a bonding site with other sites.

[0043] With the above configuration, a film exhibiting a small rate of change in retardation before and after thermal forming, excellent flexural strength, and excellent transparency can be obtained. Furthermore, a film with excellent chemical resistance can be obtained. When chemical resistance is excellent, solvent-induced cracking can be effectively suppressed when applying adhesive layers or hard coatings.

[0044] That is, by making the ends of the aromatic polycarbonate resin have the structure shown in formula (1), the glass transition temperature of the aromatic polycarbonate resin is lowered, and by making the film thickness thinner, the thermal resistance of the film is reduced, and the film is shaped in a softened state. Therefore, it is speculated that the rise of retardation (Re) during thermal shaping can be suppressed. If the rise of Re during thermal shaping is suppressed, birefringence is reduced, and iridescence inhomogeneity (coloration caused by birefringence) of the display screen can be effectively suppressed. In addition, by making the molecular weight of the aromatic polycarbonate resin within a specified range and making the film thickness thinner, it is speculated that it can be made resistant to bending, and a film with excellent bending resistance can be obtained. Furthermore, by using aromatic polycarbonate resin and reducing the surface roughness of the film, it is speculated that a film with excellent transparency can be obtained. In addition, by making the molecular weight of the aromatic polycarbonate resin within a specified range, it is speculated that a film with excellent chemical resistance can be obtained.

[0045] The following is a detailed description of this embodiment.

[0046] The membrane of this embodiment contains an aromatic polycarbonate resin having the end structure shown in Formula (1). By using such an aromatic polycarbonate resin, the glass transition temperature of the aromatic polycarbonate resin is reduced, and the increase of the heat-induced retardation (Re) can be suppressed.

[0047]

[0048] (In equation (1), R) 1 Represents an alkyl group with 8 to 36 carbon atoms or an alkenyl group with 8 to 30 carbon atoms. R 2 Each of these groups independently represents a halogen atom, an alkyl group with 1 to 20 carbon atoms, or an aryl group with 6 to 12 carbon atoms. n represents an integer from 0 to 4. * indicates a bonding site with other sites.

[0049] R 1 The term represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms, preferably an alkyl or alkenyl group having 12 or more carbon atoms, and more preferably an alkyl or alkenyl group having 14 or more carbon atoms. Additionally, R... 1 Preferably, it is an alkyl or alkenyl group with 22 or fewer carbon atoms, more preferably an alkyl or alkenyl group with 18 or fewer carbon atoms. 1 Alkyl groups are preferred. Alkyl and alkenyl groups are preferably straight-chain or branched alkyl or alkenyl groups, more preferably straight-chain alkyl or alkenyl groups.

[0050] In this embodiment, R 1 Hexadecyl is particularly preferred.

[0051] Additionally, R 1 It can be located in any position, either intermediate, opposite, or adjacent, but is preferably located in an intermediate or opposite position, and more preferably in an opposite position.

[0052] R 2 Each of the following can be independently represented: a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 12 carbon atoms, preferably a fluorine atom, a chlorine atom, a methyl group, an ethyl group, or a phenyl group, more preferably a fluorine atom, a chlorine atom, or a methyl group.

[0053] n represents an integer from 0 to 4, preferably an integer from 0 to 2, more preferably 0 or 1, and even more preferably 0.

[0054] The end structure shown in formula (1) can be added to polycarbonate by using a capping agent such as hexadecyl p-hydroxybenzoate. For details, please refer to paragraphs 0022 to 0030 of Japanese Patent Application Publication No. 2019-002023, and these contents are incorporated herein by reference.

[0055] In the aromatic polycarbonate resin with the end structure shown in Formula (1) used in this embodiment, the end structure shown in Formula (1) may be one type or two or more types.

[0056] In this embodiment, the aromatic polycarbonate resin having the end structure shown in formula (1) is preferably a bisphenol type polycarbonate resin, and more preferably a bisphenol A type polycarbonate resin.

[0057] Bisphenol A type polycarbonate resins may also have structural units other than those derived from bisphenol A and its derivatives, besides the carbonate structural units. Examples of dihydroxy compounds constituting such other structural units include, for instance, the aromatic dihydroxy compounds described in paragraph 0014 of Japanese Patent Application Publication No. 2018-154819, and these contents are incorporated herein by reference.

[0058] In the bisphenol-type polycarbonate resin of this embodiment, the carbonate structural units from bisphenol A and its derivatives preferably account for 90% or more by mass of all structural units excluding end structures, more preferably 95% or more by mass, and even more preferably 97% or more by mass.

[0059] There are no particular limitations on the manufacturing method of bisphenol A type polycarbonate resin; any method can be used. Examples include interfacial polymerization, melt transesterification, pyridine polymerization, ring-opening polymerization of cyclic carbonate compounds, and solid-phase transesterification of prepolymers.

[0060] The aromatic polycarbonate resin used in this embodiment has a viscosity-average molecular weight of 17,000 to 40,000. With a viscosity-average molecular weight of 17,000 or higher, it exhibits excellent bending resistance, resulting in a film with superior bending resistance. Furthermore, with a viscosity-average molecular weight of 40,000 or lower, it tends to effectively lower the glass transition temperature of the film, effectively suppressing the rise of Re during thermal forming.

[0061] The viscosity-average molecular weight of the aforementioned aromatic polycarbonate resin is preferably 20,000 or more, more preferably 22,000 or more, even more preferably 24,000 or more, and even more preferably 30,000 or more. In particular, by setting it to 30,000 or more, there is a tendency to further improve flexural strength. Furthermore, the viscosity-average molecular weight of the aforementioned aromatic polycarbonate resin is preferably 38,000 or less, even more preferably 35,000 or less, particularly preferably less than 30,000, and even more preferably less than 28,000. In particular, by making the viscosity-average molecular weight less than 30,000, and further less than 28,000, there is a tendency to reduce the viscosity of the aromatic polycarbonate resin and improve filter permeability. Improved filter permeability reduces foreign matter in the membrane.

[0062] In addition, when the membrane of this embodiment contains an aromatic polycarbonate resin having the end structure shown in formula (1) and other aromatic polycarbonate resins, it is preferable that the viscosity-average molecular weight of the polycarbonate resin used as an admixture satisfies the above-mentioned range.

[0063] The preferred Q value of the aromatic polycarbonate resin used in this embodiment is 30 × 10. -2 Below cc / sec, preferably 20×10 -2 Below cc / sec, further preferably 10×10 -2 Below cc / sec, 8×10 is even more preferred. -2 Below cc / sec, 4.0×10 is even more preferred. -2 Below cc / sec. By setting it below the aforementioned upper limit, there is a tendency for improved flexural strength and chemical resistance of the membrane. Furthermore, the lower limit of the aforementioned Q value is preferably 0.1 × 10⁻⁶. -2 cc / sec or higher, preferably 0.5×10 -2 cc / sec or higher, more preferably 1.0×10 -2 cc / sec or higher, and more preferably 3.0×10 - 2 For speeds above cc / sec, it can be 5.0 × 10 -2 Above cc / sec. By setting it above the lower limit mentioned above, there is a tendency for increased flowability and improved filter permeability. Increased filter permeability can reduce foreign matter in the membrane.

[0064] In addition, when the membrane of this embodiment contains an aromatic polycarbonate resin having the end structure shown in formula (1) and other aromatic polycarbonate resins, it is preferable that the Q value of the polycarbonate resin used as an admixture satisfies the above-mentioned range.

[0065] The glass transition temperature of the aromatic polycarbonate resin with the end structure shown in Formula (1) used in this embodiment is preferably 145°C or lower, more preferably 142°C or lower, even more preferably 140°C or lower, even more preferably 135°C or lower, and even more preferably 132°C or lower. By setting it to the upper limit value or lower, it tends to more effectively suppress the rise of Re during heat forming. In addition, the glass transition temperature of the aromatic polycarbonate resin with the end structure shown in Formula (1) used in this embodiment is preferably 115°C or higher, more preferably 120°C or higher, and even more preferably 123°C or higher. By setting it to the lower limit value or higher, it tends to further improve the bending resistance. In addition, when the film of this embodiment contains the aromatic polycarbonate resin with the end structure shown in Formula (1) and other aromatic polycarbonate resins, it is preferable that the glass transition temperature of the polycarbonate resin as an admixture satisfies the above range.

[0066] In this embodiment, the proportion of aromatic polycarbonate resin (preferably an aromatic polycarbonate resin having the end structure shown in formula (1)) in the membrane is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 97% by mass or more. By setting it to the lower limit or above, a membrane with better transparency can be obtained. The upper limit of the proportion of aromatic polycarbonate resin in the membrane of the above embodiment can be 100% by mass.

[0067] The membrane of this embodiment may contain only one type of aromatic polycarbonate resin, or it may contain two or more types. When it contains two or more types, the total amount is preferably within the range described above.

[0068] <Other ingredients>

[0069] In addition to containing an aromatic polycarbonate resin having the terminal structure shown in Formula (1), the membrane of this embodiment may contain other components without departing from the spirit of the invention. Specifically, it may contain polycarbonate resins other than the aromatic polycarbonate resins described above, thermoplastic resins other than polycarbonate resins, antioxidants, transesterification inhibitors, release agents, heat stabilizers, flame retardants, flame retardant additives, ultraviolet absorbers, colorants, antistatic agents, fluorescent whitening agents, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact improvers, slip improvers, hue improvers, acid traps, etc. One of these components may be used, or two or more may be used in combination. For details, please refer to Japanese Patent Application Publication No. 2017-031313, International Publication No. 2015 / 190162, Japanese Patent Application Publication No. 2019-002023, and Japanese Patent Application Publication No. 2018-199745, and these contents are incorporated into this specification.

[0070] <Membrane physical properties and characteristics>

[0071] The film thickness in this embodiment is 20 to 150 μm. By making the thickness 20 μm or more, film breakage can be suppressed, and a film with excellent strength can be obtained. Furthermore, by making the thickness 150 μm or less, the increase in Re during heat forming can be suppressed, improving flexural strength. The film thickness is preferably 25 μm or more, more preferably 30 μm or more. Additionally, the film thickness is preferably 140 μm or less, more preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 60 μm or less.

[0072] The surface roughness Ra of the membrane in this embodiment is less than 0.7 μm. By achieving this configuration, a membrane with excellent transparency can be obtained. The aforementioned 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. Regarding the lower limit of the surface roughness Ra of the membrane, ideally it is 0 μm, but it is realistic to have a value of 0.0001 μm or more, and even when it is 0.001 μm or more, the required performance can be sufficiently satisfied.

[0073] The glass transition temperature of the film in this embodiment is preferably 115 to 142°C. Setting it to the lower limit or above tends to further improve flexural strength. Furthermore, setting it to the upper limit or below tends to more effectively suppress the rise of Re during heat forming. The glass transition temperature of the film is preferably 140°C or below, more preferably 135°C or below, and even more preferably 132°C or below. Furthermore, the glass transition temperature of the film is preferably 115°C or above, more preferably 120°C or above, and even more preferably 123°C or above.

[0074] The delay (Re) of the film for light with a wavelength of 543 nm in this embodiment is preferably 25 nm or less, more preferably 15 nm or less, even more preferably 10 nm or less, even more preferably 8 nm or less, even more preferably 5 nm or less, and even more preferably 3 nm or less. By setting it to the upper limit value mentioned above, the tendency for rainbow inhomogeneity is more effectively suppressed. Regarding the lower limit value of the above delay (Re), ideally it is 0 nm, but it is realistic to have a value of 0.01 nm or more.

[0075] The haze of the film in this embodiment is preferably 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 it below the above-mentioned upper limit value, there is a tendency to further improve the transparency of the film. Regarding the lower limit value of the haze of the film, 0% is ideal, but 0.001% or more is realistic.

[0076] The Ra, glass transition temperature, Re, and haze described above can be measured based on the description in the embodiments described later.

[0077] <Membrane Manufacturing Method>

[0078] The membrane of this embodiment can be manufactured using known methods, such as extrusion molding or casting molding, which are preferred. As an example of extrusion molding, a method can be described as follows: Granules, flakes, or powders of a resin composition containing aromatic polycarbonate resin and desired additives are melted and mixed using an extruder, and then extruded from a T-die, etc. While the semi-molten sheet is clamped using polishing rollers, it is cooled and solidified to form an article. The extruder can be a single-screw or a twin-screw extruder; it can also be used with or without ventilation openings.

[0079] When the film of this embodiment is a multilayer body, it can also be manufactured by known methods. For example, when performing melt extrusion using a T-die, it can be formed into a film by stacking layers inside the die, or by stacking layers after forming the film, thereby forming a multilayer film.

[0080] <Uses>

[0081] The membrane of this embodiment can be used as a single-layer membrane. Alternatively, as described above, the membrane of this embodiment can also be used as a multilayer having the membrane of this embodiment and at least one other layer. As the other layer mentioned above, known layers can be used, such as an adhesive layer or a hard coating layer, with an adhesive layer being preferred. Of course, both an adhesive layer and a hard coating layer can also be included.

[0082] As an adhesive layer, a polyolefin resin layer can be exemplified.

[0083] As a hard coating, reference can be made to the descriptions in paragraphs 0045 to 0055 of Japanese Patent Application Publication No. 2013-020130, paragraphs 0073 to 0076 of Japanese Patent Application Publication No. 2018-103518, and paragraphs 0062 to 0082 of Japanese Patent Application Publication No. 2017-213771, and these contents are incorporated into this specification.

[0084] The membrane in this embodiment is preferably used as a protective film or substrate for a transparent conductive membrane. It is particularly preferred to use it as a transparent conductive membrane, which sequentially comprises a protective layer, an adhesive layer, a substrate, and an electrode layer, wherein at least one of the substrate and the protective layer (preferably at least the protective layer) is the membrane of this embodiment.

[0085] Furthermore, the aforementioned transparent conductive film is preferably used as a transparent conductive film for use in film sensors of touch screens, electronic paper, pigment-sensitized solar cells, touch sensors, and the like.

[0086] Furthermore, in addition to the above, the membrane of this embodiment is preferably used for applications requiring a small rate of change in delay before and after heat forming, excellent bending resistance, and high transparency. For example, it can be used as an anti-scattering membrane.

[0087]

Example

[0088] The present invention will be described in more detail below with examples. The materials, amounts, proportions, processing contents, processing steps, etc., shown in the following examples can be appropriately modified without departing from the spirit of the invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0089] When the measuring equipment used in the embodiments is not readily available due to obsolescence or other reasons, other equipment with equivalent performance can be used for measurement.

[0090] 1. Raw materials

[0091] <Manufacturing example of PC-1>

[0092] Based on the description in the Organic Chemistry Handbook (pp. 143-150), 4-hydroxybenzoic acid produced by Tokyo Chemical Industry Co., Ltd. and 1-hexadecyl alcohol produced by Tokyo Chemical Industry Co., Ltd. were used to carry out esterification by dehydration reaction to obtain hexadecyl p-hydroxybenzoate (CEPB).

[0093] Add 7.1 kg (31.14 mol) of bisphenol A (BPA) manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd. and 30 g of sodium dithionite to 57.2 kg of a 9% sodium hydroxide aqueous solution and dissolve them. Add 40 kg of dichloromethane while stirring and maintaining the solution temperature within the range of 15–25°C, and blow in 4.33 kg of carbonyl chloride over 30 minutes.

[0094] After the carbonyl chloride was blown in, 6 kg of 9% sodium hydroxide aqueous solution, 11 kg of dichloromethane, and a solution obtained by dissolving 443 g (1.22 mol) of CEPB obtained above in 10 kg of dichloromethane were added. The mixture was stirred vigorously to emulsify it, and then 10 mL of triethylamine was added as a polymerization catalyst. Polymerization was carried out for about 40 minutes.

[0095] The polymerization solution was separated into an aqueous phase and an organic phase. The organic phase was neutralized with phosphoric acid, and the solution was repeatedly washed with pure water until the pH of the washing solution reached neutral. The organic solvent was removed by evaporation from the purified aromatic polycarbonate resin solution, thereby obtaining aromatic polycarbonate resin powder (PC-1).

[0096] To 100 parts by weight of the obtained aromatic polycarbonate resin powder, 0.0075 parts by weight of ADEKASTAB 2112 (manufactured by ADEKA Corporation, tris(2,4-di-tert-butylphenyl) phosphite) as an antioxidant and 0.0045 parts by weight of RIKEMAL S-100A (manufactured by RIKEN VITAMIN CO.,LTD., glyceryl monostearate) as a release agent were added. After mixing in a drum for 15 minutes, the mixture was melt-blended at a barrel temperature of 280°C using a vented twin-screw extruder ("TEX30α" manufactured by Nippon Steel Works Co., Ltd.) with a screw diameter of 32 mm. Granules were then obtained using a skewer cutter. The viscosity-average molecular weight (Mv) and glass transition temperature (Tg) of the obtained aromatic polycarbonate resin granules were determined.

[0097] <Manufacturing example of PC-2>

[0098] In the above <PC-1 manufacturing example>, CEPB was 348g (0.96mol), and the other steps were carried out in the same manner.

[0099] <Manufacturing example of PC-3>

[0100] In the above <PC-1 manufacturing example>, CEPB was made into 266g (0.73mol), and the other steps were carried out in the same manner.

[0101] <Manufacturing example of PC-4>

[0102] In the above <PC-1 manufacturing example>, CEPB was 940g (2.59mol), and the other steps were carried out in the same manner.

[0103] <Manufacturing example of PC-5>

[0104] In the above-mentioned <PC-1 manufacturing example>, the aromatic polycarbonate resin powder used in the production of granules was a mixture of bisphenol A type polycarbonate resin with a terminal structure of p-tert-butylphenyl (manufactured by Mitsubishi Engineering Plastics Co., Ltd., E-2000F, viscosity-average molecular weight: 28000, Tg: 150°C) and bisphenol A type polycarbonate resin with a terminal structure of p-tert-butylphenyl (manufactured by Mitsubishi Engineering Plastics Co., Ltd., S-3000F, viscosity-average molecular weight: 21000, Tg: 146°C) in a mass ratio of 1:1, and other processes were carried out in the same manner.

[0105] <Filter performance>

[0106] When manufacturing the above granules, a polymer filter with a mesh size of 20μm is installed on a twin-screw extruder with a vent. The case where the pressure exceeds the upper limit and extrusion cannot be performed is referred to as B, and the case where extrusion is successful is referred to as A.

[0107] <Determination of viscosity-average molecular weight (Mv)>

[0108] The viscosity-average molecular weight of aromatic polycarbonate resins was determined using the following method.

[0109] Using dichloromethane as a solvent, the intrinsic viscosity [η] (unit: dL / g) at 25°C was determined using an Uberloud viscometer. According to Schnell's viscosity formula, η = 1.23 × 10⁻⁶. -4 Mv 0.83 Calculated. Additionally, intrinsic viscosity [η] is the specific viscosity [η] measured at each solution concentration [C] (g / dL). sp And the value is calculated using the following formula.

[0110]

[0111] <Q value>

[0112] The obtained granules were dried for 5 hours at 110°C using a high-efficiency flow tester and a hot air circulating dryer, with a load of 160 kgf / cm². 2 Hole: 1 mm in diameter × 10 mm in length, Q value of aromatic polycarbonate resin determined at 280℃. The unit of Q value is expressed as 0.01 cc / sec.

[0113] The high-performance flow tester uses the Shimadzu CFT-500D manufactured by Shimadzu Corporation.

[0114] <Determination of Glass Transition Temperature (Tg)>

[0115] The glass transition temperatures of the membrane and aromatic polycarbonate resin granules were determined as described below.

[0116] For approximately 10 mg of membrane or aromatic polycarbonate resin granules, two cycles of heating and cooling were performed under the DSC (Differential Scanning Calorimetry) conditions described below. The glass transition temperature during the heating phase of the second cycle was measured. The intersection of the line obtained by extending the baseline from the low temperature side to the high temperature side and the tangent at the inflection point was taken as the starting glass transition temperature. The intersection of the line obtained by extending the baseline from the high temperature side to the low temperature side and the tangent at the inflection point was taken as the ending glass transition temperature. The midpoint between the starting and ending glass transition temperatures was taken as the glass transition temperature (Tg, unit: °C) of this invention.

[0117] Measurement start temperature: 30℃

[0118] Heating rate: 10℃ / minute

[0119] Reaching temperature: 250℃

[0120] Cooling rate: 20℃ / minute

[0121] The measuring apparatus used was a differential scanning calorimeter (DSC, manufactured by Hitachi Advanced Technology Co., Ltd., “DSC7020”).

[0122] 2. Examples 1-5, Comparative Examples 1-4

[0123] <Membrane Manufacturing>

[0124] Using the granules obtained above, a membrane is manufactured according to the following method.

[0125] Using a T-die melt extruder with a vented twin-screw extruder (manufactured by Nippon Steel Corporation, "TEX30α") ​​including a 32mm diameter drum and a screw L / D ratio of 31.5, the obtained granules were melt-extruded at a discharge rate of 10kg / h and a screw speed of 150rpm. After being pressed together by the first and second rollers, the granules were cooled and solidified to form a film. The barrel and T-die temperatures were 280°C.

[0126] Adjust the roller speeds of the first and second rollers to obtain the final film thickness (in μm) as shown in Table 1 or Table 2.

[0127] The details of the first and second rollers used are as follows.

[0128] • First roller: Manufactured by Mochida Shoko Co., Ltd., silicone rubber roller (IT68S-MCG) Dimensions: outer diameter 260mm × width 600mm

[0129] Roller temperature: 50℃

[0130] • Second roller: Mirror-finish metal rigid roller (surface: hard chrome treatment)

[0131] Core mold dimensions: outer diameter 250mm × width 600mm

[0132] Roller temperature: 120℃

[0133] The obtained membrane was evaluated as follows.

[0134] Comparative Example 2 broke during film manufacturing, therefore, no evaluation was given for items marked "-" in Table 2.

[0135] <Surface Roughness (Ra)>

[0136] For the membrane obtained above, the arithmetic mean surface roughness Ra was measured using a contact surface roughness meter. Specifically, based on JIS B0601:2001, for the surface of the membrane in contact with the second roller, three points in the width direction were measured, and the average value was calculated. The unit is expressed in μm.

[0137] The measuring device used is the “SURFTEST SJ-210” manufactured by Mitutoyo Corporation.

[0138] <Delay (Re)>

[0139] The obtained membrane was cut into 50×150mm pieces to measure the delay at a wavelength of 543nm. The unit is expressed in nm.

[0140] The delay was measured using a WPA-100 manufactured by Photonic Lattice Inc.

[0141] <Delay rise rate (ΔRe) before and after thermal shaping>

[0142] The obtained membrane was cut into 50×150mm pieces to measure the delay at a wavelength of 543nm. Regarding the measurement results, a 100mm line analysis was performed along the length direction from positions 25mm from the short side end and 25mm from the long side end of the membrane; the maximum value of this line analysis was taken as the maximum delay before thermal forming. The membrane was then installed on a hydraulic jack-type pressing machine. Figure 2 The upper mold 21 and lower mold 22 are shown. The molds are heated to 130°C, and the film after delay measurement is placed on the molds. The gap between the upper and lower molds is maintained at 1 mm for 1 minute, and heat forming is performed under a pressure of 0.5 MPa and a pressurization time of 1 minute. The film is then removed and cooled to 23°C. The delay is measured again in the same manner as before heat forming, and the maximum delay after heat forming is calculated. The delay rise rate (unit: %) before and after heat forming is calculated using the following formula.

[0143] Delay rise rate = [(Maximum delay after thermal shaping - Maximum delay before thermal shaping) / Maximum delay before thermal shaping] × 100

[0144] The delay was measured using a WPA-100 manufactured by Photonic Lattice Inc.

[0145] The calculated rate of retardation is evaluated and judged according to the following criteria.

[0146] A: Below 50%;

[0147] B: More than 50% but less than 120%;

[0148] C: Over 120%.

[0149] <Drug Resistance>

[0150] The obtained granules were dried at 110°C for 5 hours using a hot air circulating dryer. Then, 3mm ISO multi-object test pieces were formed using an injection molding machine under the conditions of barrel temperature 280°C, mold temperature 80°C, and molding cycle 45 seconds (the thickness of the JIS-K7139 A1 type was changed from 4mm to 3mm).

[0151] The injection molding machine used was a Sodick PE-100 (trade name). The resulting test pieces were annealed in an oven at 110°C for 2 hours. Figure 3 As shown, while applying a 0.45% deformation to the annealed test piece, 2,2-bis(4-glycidoxyphenyl)propane, the test substance, was coated. After being kept in an oven at 75°C for 3 hours, it was cooled to 23°C. Figure 3 In the diagram, 31 represents the test piece, and L represents the distance between the support points.

[0152] The deformation [ε] (%) is calculated using the following formula, based on the bending [s] (mm) of the test piece, the thickness [h] (mm) of the test piece, and the distance between the support points [L] (mm).

[0153] ε=600sh / L 2

[0154] use Figure 3 The bending [s] (mm) of the test piece is calculated using the following formula, based on the given I0 (mm) and I (mm).

[0155] s = I0 - I

[0156] The test samples were evaluated visually according to the following criteria. Five experts participated in the evaluation, and the judgment was made by majority vote.

[0157] A: The coated surface was damaged by the drug, but the test piece did not break.

[0158] B: The test piece broke.

[0159] <Bending resistance>

[0160] The obtained film was cut into 75×25mm pieces and subjected to a bending resistance test with a curvature radius of 4.0mm using an FPC (Flexible Printed Circuit Board) bending tester based on JIS C5016:1994. In this bending resistance test, the test samples were evaluated visually after 2000 bending tests according to the following criteria. Five experts evaluated the samples, and a majority vote was taken.

[0161] As an FPC bending testing machine, the "No.306FPC Bending Testing Machine" (trade name) manufactured by Yasuda Seiki Co., Ltd. is used.

[0162] S: No deformation or cracks occurred in the membrane.

[0163] A: The membrane deformed slightly into an arc shape, but no cracks were formed.

[0164] B: The membrane deformed into an arc shape, but no cracks were formed.

[0165] C: In addition to A and B above, for example, the film may deform into an arc shape, resulting in cracks, etc.

[0166] <Haze>

[0167] The haze (unit: %) of the obtained film was measured using a haze meter under the conditions of D65 light source and 10° field of view.

[0168] The haze meter used is the "HM-150" manufactured by Murakami Color Technology Research Institute Co., Ltd.

[0169] Comparative Example 5

[0170] In the manufacture of the membrane, the following changes were made, while the rest were the same as in Example 1.

[0171] • Second roller: Embossing roller with an arithmetic mean roughness of 2.4 μm

[0172] Core mold dimensions: outer diameter 250mm × width 600mm

[0173] Roller temperature: 120℃

[0174] Comparative Example 5 had high haze due to the use of an embossing roller, making it unsuitable for use as an optical film. Therefore, no evaluation was conducted on retardation, retardation rise rate before and after heat forming, chemical resistance, or flexural strength.

[0175] Table 1

[0176]

[0177] Table 2

[0178]

Claims

1. A membrane, characterized in that: Contains an aromatic polycarbonate resin having the end structure shown in formula (1), The aromatic polycarbonate resin has a viscosity-average molecular weight of 17,000 to 40,000. The thickness of the membrane is 20–150 μm. The surface roughness Ra of the membrane is less than 0.7 μm. In equation (1), R 1 R represents an alkyl group with 8 to 36 carbon atoms or an alkenyl group with 8 to 30 carbon atoms. 2 Each of the following can be independently represented: a halogen atom, an alkyl group with 1 to 20 carbon atoms, or an aryl group with 6 to 12 carbon atoms. n represents an integer from 0 to 4, and * represents a bonding site with other sites.

2. The membrane as described in claim 1, characterized in that: The glass transition temperature of the membrane is 115–142 °C.

3. The membrane as described in claim 1 or 2, characterized in that: The viscosity-average molecular weight of the aromatic polycarbonate resin is 30,000 to 40,000.

4. The membrane as described in claim 1 or 2, characterized in that: The viscosity-average molecular weight of the aromatic polycarbonate resin is above 17,000 and less than 30,000.

5. The membrane as described in claim 1 or 2, characterized in that: The surface roughness Ra of the membrane is less than 0.1 μm.

6. The membrane as described in claim 1 or 2, characterized in that: The haze of the membrane is below 10%.

7. The membrane as described in claim 1 or 2, characterized in that: The film has a delay Re of less than 25 nm for light with a wavelength of 543 nm.

8. The membrane as described in claim 1 or 2, characterized in that: It is a single-layer membrane.

9. A multilayer body, characterized in that: It has a membrane as described in any one of claims 1 to 8 and at least one other layer.

10. The multilayer body as described in claim 9, characterized in that: The other layers include adhesive layers.

11. A transparent conductive film, characterized in that: It consists of a protective layer, an adhesive layer, a substrate, and an electrode layer, in sequence. At least one of the substrate and the protective layer is the membrane according to any one of claims 1 to 8.

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