Transparent film and transparent electrode

Abstract

Provided is a transparent film having advantages such as excellent heat resistance, a birefringence that is not easily affected by the film forming conditions, and being uniform. According to one embodiment, there is provided a transparent film including a resin composition that includes a polycarbonate resin (A) having a structural unit represented by formula (1) and having a photoelastic coefficient of 80×10.sup.−12 m.sup.2/N or less. ##STR00001##

Claims

1. A transparent film comprising a resin composition including a polycarbonate resin (A) having a structural unit represented by formula (1) and a polycarbonate resin (B) including a structural unit represented by formula (3), said transparent film having a photoelastic coefficient of 80×10.sup.−12 m.sup.2/N or less: ##STR00016## wherein R.sub.1 to R.sub.4 are each independently a hydrogen atom, an alkyl group, or an aryl group; and X is a single bond or a group represented by the following formula (2): ##STR00017## wherein R.sub.5 and R.sub.6 are a hydrogen atom, an alkyl group, or an aryl group; and at least one of R.sub.5 and R.sub.6 is an aryl group, ##STR00018## the resin composition comprises a mixture of the polycarbonate resin (A) and a polycarbonate resin (B), and a ratio of the polycarbonate resin (A) to a total mass of the polycarbonate resin (A) and the polycarbonate resin (B) is 10 to 90% by mass, and wherein the structural unit represented by formula (1) is, with respect to all of the structural units of the polycarbonate resin (A), included in a ratio of 95 to 100 mol %.

2. The transparent film according to claim 1, wherein the structural unit represented by formula (1) includes a structural unit represented by the following formula (4) or (5) ##STR00019##

3. The transparent film according to claim 1, wherein the resin composition has a glass transition temperature of 150 to 185° C.

4. The transparent film according to claim 1, wherein the resin composition has a shear viscosity at 300° C. and a shear rate of 30 to 250 sec.sup.−1 of 300 to 1200 Pa.Math.s.

5. The transparent film according to claim 1, wherein the transparent film has a thickness of 30 to 200 μm.

6. The transparent film according to claim 1, further laminated with a high hardness resin layer having a pencil hardness of H or more.

7. An optical film comprising the transparent film according to claim 1.

8. The transparent film according to claim 1, wherein the transparent film is a film for a transparent electrode base material.

9. A transparent electrode comprising the transparent film according to claim 8 and a transparent electrode layer laminated on the transparent film.

10. The transparent electrode according to claim 9, wherein the transparent electrode layer includes one or more of ATO (antimony-doped indium oxide), FTO (fluorine-doped tin oxide), AZO (aluminum-doped zinc oxide), GZO (gallium-doped zinc oxide), ITO (indium tin composite oxide), Ag, Cu, Au, and a carbon nanotube.

11. The transparent film according to claim 1, wherein the transparent film is a protective film.

12. The transparent film according to claim 1, wherein the photoelastic coefficient is 57.1×10.sup.−12 m.sup.2/N to 80×10.sup.−12 m.sup.2/N.

13. A transparent film comprising a resin composition including a polycarbonate resin (A) having a structural unit represented by formula (1) and a polycarbonate resin (B) including a structural unit represented by formula (3), said transparent film having a photoelastic coefficient of 80×10.sup.−12 m.sup.2/N or less: ##STR00020## wherein R.sub.1 to R.sub.4 are each independently a hydrogen atom, an alkyl group, or an aryl group; and X is a single bond or a group represented by the following formula (2): ##STR00021## wherein R.sub.5 and R.sub.6 are a hydrogen atom, an alkyl group, or an aryl group; and at least one of R.sub.5 and R.sub.6 is an aryl group, ##STR00022## the resin composition comprises a mixture of the polycarbonate resin (A) and a polycarbonate resin (B), a ratio of the polycarbonate resin (A) to a total mass of the polycarbonate resin (A) and the polycarbonate resin (B) is 10 to 90% by mass, and the resin composition comprises 10% by mass or less of a resin other than the polycarbonate resin (A) and the polycarbonate resin (B).

14. The transparent film according to claim 13, wherein the structural unit represented by formula (1) includes a structural unit represented by the following formula (4) or (5) ##STR00023##

15. The transparent film according to claim 13, wherein the resin composition has a glass transition temperature of 150 to 185° C.

16. The transparent film according to claim 13, wherein the resin composition has a shear viscosity at 300° C. and a shear rate of 30 to 250 sec.sup.−1 of 300 to 1200 Pa.Math.s.

17. The transparent film according to claim 13, wherein the transparent film has a thickness of 30 to 200 μm.

18. The transparent film according to claim 13, further laminated with a high hardness resin layer having a pencil hardness of H or more.

19. An optical film comprising the transparent film according to claim 13.

20. The transparent film according to claim 13, wherein the transparent film is a film for a transparent electrode base material.

21. A transparent electrode comprising the transparent film according to claim 20 and a transparent electrode layer laminated on the transparent film.

22. The transparent electrode according to claim 21, wherein the transparent electrode layer includes one or more of ATO (antimony-doped indium oxide), FTO (fluorine-doped tin oxide), AZO (aluminum-doped zinc oxide), GZO (gallium-doped zinc oxide), ITO (indium tin composite oxide), Ag, Cu, Au, and a carbon nanotube.

23. The transparent film according to claim 13, wherein the transparent film is a protective film.

24. The transparent film according to claim 13, wherein the photoelastic coefficient is 57.1×10.sup.−12 m.sup.2/N to 80×10.sup.−12 m.sup.2/N.

Description

EXAMPLES

(1) The present invention will now be described in detail with reference to examples, but the subject matter of the present invention is not limited thereto.

(Synthesis Example 1: Synthesis of Polycarbonate Resin (A))

(2) 34 liters of an 8.0% mass/mass solution of aqueous sodium hydroxide, 5800 g of 1,1-bis(4-hydroxyphenyl)-1-phenylethane (BPAP) (manufactured by Honshu Chemical Industrial Co., Ltd., 20.00 mol), and 10 g of hydrosulfite were charged into a 100 liter reaction vessel and mixed. 22 liters of dichloromethane was added to the resultant mixture, and 2600 g of phosgene was blown therein over 30 minutes while stirring at 15° C.

(3) After the blowing was finished, the reaction solution was emulsified by vigorously stirring for 1 minute, and 240 g of p-tertiary-butylphenol (PTBP, 1.60 mol) was added. After stirring for another 10 minutes, 20 mL of triethylamine was added, and stirring was continued for another 50 minutes.

(4) The obtained liquid was separated into an aqueous phase and an organic phase, and the organic phase was neutralized with phosphoric acid. Washing with water was repeated until the conductivity of the cleaning liquid reached 10 μS/cm or less, to thereby obtain a purified resin liquid. The obtained resin solution was diluted with dichloromethane to adjust to 10.0% mass/mass. The resin solution was added dropwise to warm water maintained at 45° C., and the solvent was removed by evaporation to obtain a white precipitate. The obtained precipitate was filtered off and dried at 120° C. for 24 hours to obtain a powder of the polycarbonate resin (A). The polycarbonate resin (A) contained a structural unit represented by the above formula (4) (a structural unit derived from 1,1-bis(4-hydroxyphenyl)-1-phenylethane (BPAP)) as a main component (bisphenol AP). The viscosity average molecular weight of the polycarbonate resin (A) was 12,000.

Example 1

(5) The powder of the polycarbonate resin (A) produced in Synthesis Example 1 was melt-kneaded with a twin-screw extruder equipped with a vent and extruded into a film. The film was dropped between a first cooling roll and a second cooling roll of a film forming machine having three cooling rolls arranged perpendicularly to the molding direction, and the film was pressure-bonded by those rolls to obtain a film having a width of 250 mm and a thickness of 160 μm. At that time, two types of samples were obtained, one in which the pressing pressure of the first cooling roll and the second cooling roll was 5 kPa and the other in which the pressing pressure was 2 kPa.

Example 2

(6) Using a blender, 5.0 kg of the polycarbonate resin (A) produced in Synthesis Example 1 and 5.0 kg of E-2000F (a bisphenol A type polycarbonate manufactured by Mitsubishi Engineering-Plastics Corporation) having a viscosity average molecular weight of 27500, which is the polycarbonate resin (B) including a structural unit represented by the above formula (3), were stirred and uniformly mixed. Using the obtained powder, a film was prepared in the same manner as in Example 1.

Example 3

(7) Using a blender, 3.0 kg of the polycarbonate resin (A) produced in Synthesis Example 1 and 7.0 kg of E-2000F (manufactured by Mitsubishi Engineering-Plastics Corporation) having a viscosity average molecular weight of 27500 were stirred and uniformly mixed. Using the obtained powder, a film was prepared in the same manner as in Example 1.

Example 4

(8) Using a blender, 1.0 kg of the polycarbonate resin (A) produced in Synthesis Example 1 and 9.0 kg of E-2000F (manufactured by Mitsubishi Engineering-Plastics Corporation) having a viscosity average molecular weight of 27500 were stirred and uniformly mixed. Using the obtained powder, a film was prepared in the same manner as in Example 1.

Comparative Example 1

(9) A film was prepared in the same manner as in Example 1 using 10.0 kg of E-2000F (manufactured by Mitsubishi Engineering-Plastics Corporation) having a viscosity average molecular weight of 27500.

Comparative Example 2

(10) A film was prepared in the same manner as in Example 1 using 10.0 kg of the polycarbonate resin H-4000F (manufactured by Mitsubishi Engineering-Plastics Corporation) having a viscosity average molecular weight of 16000.

(11) The physical properties of the resins and films of the examples and comparative examples were evaluated as follows.

(12) (1) Shear Viscosity

(13) The resins of the examples and comparative examples were charged into a Capillograph B1 manufactured by Toyo Seiki Co., Ltd., the resins were extruded at 300° C. from a nozzle hole (orifice) having a length of 10 mm and a diameter of 1.0 mm, and the shear viscosity at a shear rate of 30 to 250 sec.sup.−1 was measured.

(14) (2) Glass Transition Temperature

(15) The glass transition temperature of the resins of the Examples and Comparative Examples was measured with an EXTAR DSC7020 manufactured by Hitachi High-Tech Science Corporation. Approximately 10 mg of the object to be measured was placed in a non-sealed aluminum container, heated to 300° C. at a heating rate of 5° C./min in a nitrogen gas stream, and then the temperature was lowered to 40° C. The temperature was raised again under the same conditions to obtain a DSC curve. A tangent line was drawn on the DSC curve between two baselines before and after transition (a glass state baseline and a molten state baseline), and the temperature at the intersection of the tangent line and the baseline on the glass state side was used as the glass transition temperature.

(16) (3) Photoelastic Coefficient

(17) The films obtained in the examples and comparative examples were annealed. The films after the annealing treatment were subjected to a stress load (0 to 720 gf) using an ellipsometer M-220 manufactured by JASCO Corporation in an environment of 23° C. and a relative humidity of 50% to measure the retardation (Re) value in the film plane at a wavelength of 633 nm. Then, the photoelastic coefficient was calculated from the stress and the Re slope.

(18) (4) Haze

(19) The haze of the films obtained in the examples and comparative examples was measured using an HM-150 manufactured by Murakami Color Research Laboratory in accordance with JIS K7136.

(20) (5) Retardation (Re)

(21) Using a WPA-100 manufactured by Photonics Lattice Inc., the retardation in the film width direction of the films produced in the examples and comparative examples (roll pressing pressures of 5 MPa and 2 MPa, respectively) was measured at 0.5 mm intervals by selecting a measurement wavelength of 523 nm. The average value of the retardation values obtained for each sample was calculated and used as the “Re average value”. Further, for each of the examples and comparative examples, the difference between the Re average value of the sample having a roll pressing pressure of 5 MPa and the sample having a roll pressing pressure of 2 MPa (5 MPa Re average value−2 MPa Re average value) was calculated and used as the “Re average change amount”. In addition, the ratio of the Re average change amount to the Re average value of the 5 MPa sample (Re average change amount/5 MPa Re average value) was calculated and used as the “Re average change rate”.

(22) The evaluation results of the physical properties are shown in Table 1 below.

(23) TABLE-US-00001 TABLE 1 Resin (A): Resin (B): Glass Roll Re Re Re (main component: (main component: Shear Photoelastic transition pressing average average average bisphenol AP) bisphenol A) viscosity coefficient temperature Haze pressure value change change (% by mass) (% by mass) (Pa .Math. s) (10.sup.−12m.sup.2/N) (° C.) (%) (MPa) (nm) amount (nm) rate (%) Example 1 100 0 500 57.1 168 0.1 5 119 25 21 2 96 Example 2 50 50 760 61.0 156 0.1 5 156 39 25 2 117 Example 3 30 70 900 72.2 154 0.1 5 164 41 25 2 130 Example 4 10 90 1100 74.1 151 0.1 5 218 74 34 2 179 Comparative 0 100 1200 85.1 150 0.1 5 237 85 36 Example 1 2 152 Comparative 0 100 200 84.1 140 0.1 5 280 151 54 Example 2 2 131

(24) From Table 1, it can be seen that birefringence in the transparent film of the present invention is not easily affected by the film forming conditions.

(25) Although several embodiments of the present invention have been described above, these embodiments are presented as examples, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other modes, and various omissions, replacements, and changes can be made thereto without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and spirit of the invention, and are also included in the scope of the equivalents to the invention recited in the claims.