Optically functional film, phase difference film, composition for formation of optically functional layer, and method for manufacture of optically functional film

A technology of optical functional layer and retardation film, which is applied in the direction of optics, nonlinear optics, layered products, etc., can solve the problem of white turbidity of the optical functional layer, and achieve high transparency, excellent adhesion, and excellent transparency Effect

Inactive Publication Date: 2008-10-01

DAI NIPPON PRINTING CO LTD

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AI-Extracted Technical Summary

Problems solved by technology

[0015] However, the above-mentioned retardation film without an alignment film is usually coated with an optical function containing the above-mentioned rod-shaped compound on a substrate having the property of being a negative ...

Method used

As exemplified in Figure 1, the optical functional film of the present invention can make the substrate and the optical functional layer adhere firmly by directly forming the optical functional layer on the above-mentioned substrate, therefore, it has the function of not interlayer over time. Advantages of stripping etc. In addition, along with the improvement of adhesiveness, there are also advantages such as improvement in alkali resistance and reworkability.

As illustrated in Figure 3, the retardation film of this mode can make the substrate and the retardation layer adhere firmly by directly forming the retardation layer on the above-mentioned substrate, therefore, it has the advantage of superior adhesion stability. In addition, along with such an improvement in adhesiveness, there are also advantages such as improvement in alkali resistance and reworkability.

In addition, utilize the optical function film of the present invention to make by directly forming optical function layer on above-mentioned base material, can make base material and optical function layer adhere firmly, therefore, have interlayer peeling etc. not because of the time-lapse advantage.

Retardation film of the present invention, it comprises: have as the property of above-mentioned A plate or B plate and as the base material of the property of negative C plate and the retardation film containing the retardation layer of rod-shaped compound. Since the aforementioned retardation layer is formed as a rod-shaped compound with random and uniform orientation, it is excellent in the development of optical characteristics that function as a negative C plate. Therefore, the retardation film of the present invention has properties as an A plate or a B plate as a whole. , and as a negative property of the C plate. The retardation film of the present invention has such optical properties. Therefore, conventionally, two retardation films having the properties of an optically negative C plate and an A plate or a B plate have been used to improve the viewing angle dependence of liquid crystal display devices. In the method, the retardation film of the present invention can achieve its purpose with one sheet.

The properties of the base material used in the present invention as an optically negative C plate can be appropriately selected according to the type of the rod-shaped compound used in the above-mentioned optical functional layer, or the optical characteristics required for the optical functional film of the present invention. Can. Among them, in the present invention, the thickness-direction retardation (Rth) of the substrate is preferably in the range of 20 to 100 nm, particularly preferably in the range of 25 nm to 80 nm, particularly preferably in the range of 30 nm to 60 nm. This is because, by setting the retardation (Rth) in the thickness direction within the above range, random uniform alignment can be easily formed in the optical function layer regardless of the type of the rod-shaped compound. In addition, it is because more homogeneous random uniform orientation can be formed by making Rth of the said base material into the said range.

Utilize the optical function film of the present invention manufacture, it is characterized in that, owing to use above-mentioned optical function layer forming composition to form optical function layer, transparency is superior.

[0112] The rod-shaped compound used in the present invention is preferably a compound having a polymerizable functional group in the molecule, and preferably has a polymerizable functional group capable of three-dimensional crosslinking. This is because: by making the above-mentioned rod-shaped compound have a polymerizable functional group, the above-mentioned rod-shaped compound can be polymerized and fixed. Therefore, by immobilizing the above-mentioned rod-shaped compound in a state where random and uniform orientation is formed, excellent alignment stability can be obtained. Optically functional films with varying properties. In addition, in the present invention, a rod-shaped compound having the above-mentioned polymerizable functional group and a rod-shaped compound not having the above-mentioned polymerizable functional group may be mixed.

[0151] In addition, as long as the base material used in the present invention possesses the above-mentioned optical properties, a flexible material with flexibility may be used, or a rigid material without flexibility may be used, but a flexible material is preferably used. This is because, by using a flexible material, the production process of the optical functional film of the present invention can be performed as a roll-to-roll process, and an optical functional film excellent in productivity can be obtained.

[0155] In the present invention, among the above-mentioned lower fatty acid esters, acetyl cellulose is particularly suitably used. As cellulose acetate, it is most preferable to use triacetyl cellulose having an average degree of acetylation of 57.5 to 62.5% (degree of substitution: 2.6 to 3.0). This is because triacetyl cellulose has a structure having relatively large side chains. Therefore, by constituting the base material with triacetyl cellulose, the rod-shaped compound forming the above-mentioned optical function layer is easy to penetrate the base material, so further improvement can be achieved. Adhesion between substrate and optically functional layer. In addition, since triacetyl cellulose tends to exhibit the property of being an optically negative C plate, it is possible to easily form random uniform orientation of the above-mentioned rod-shaped compound. Here, the degree of acetylation refers to the amount of bound acetic acid per unit mass of cellulose. The degree of acetylation can be ...

Abstract

The main object is to provide an optically functional film which can exert excellent optical properties without the need of using any oriented film and has an excellent property of closely adhering to various layers and excellent display quality. The optically functional film comprises a substrate having properties required of an optically negative C-plate and an optically functional layer formed on the substrate and comprising a rod-shaped compound. The optically functional layer is formed on the substrate directly. The rod-shaped compound forms a random homogeneous orientation in the optically functional layer.

Application Domain

Layered productsPolarising elements +1

Technology Topic

ChemistryOptical property +1

Image

Examples

Experimental program(6)
Comparison scheme(3)

Example Embodiment

[0380] (Example 1)

[0381] 20% by mass of the compound (I) represented by the following formula as a rod-shaped compound was dissolved in cyclohexanone and coated with a rod on a substrate composed of a TAC film (manufactured by Fuji Photo Film Co., Ltd., trade name: TF80UL) The coating was applied so that the coating amount after drying was 2.5 g/m2. Then, it was heated at 90°C for 4 minutes to dry and remove the solvent, and the rod-shaped compound was immersed in the TAC film, and the coated surface was irradiated with ultraviolet rays to immobilize the rod-shaped compound to produce a retardation film. The obtained retardation film was used as a sample, and the following items were evaluated.

[0382] [化3]

[0383]

[0384] 1. Random uniform orientation

[0385] Using KOBRA-WR manufactured by Oji Measuring Instruments Co., Ltd., Rth and Re were measured for the produced retardation film and the above-mentioned TD80UF by the parallel Nicol rotation method. Regarding Rth and Re, the measured value of TD80UF was subtracted from the measured value of the retardation film to obtain the Rth and Re of the optical functional layer. Here, for the measurement of the above-mentioned Re and Rth, a product made by Oji Measuring Instruments Co., Ltd., trade name: KOBRA-21ADH was used. In addition, the Nippon Denshoku Kogyo Co., Ltd. product, brand name: NDH2000 was used for the measurement of the above-mentioned turbidity. Furthermore, for the confirmation of the presence or absence of the above-mentioned selective reflection wavelength, a product made by Shimadzu Corporation, trade name: UV-3100PC was used. As a result, Rth = 117.9 nm and Re = 0 nm. In addition, the haze was 0.2%.

[0386] Furthermore, it was confirmed that the retardation film did not have a selective reflection wavelength using an ultraviolet-visible-gold-infrared spectrophotometer (UV-3100) manufactured by Shimadzu Corporation.

[0387] 2. Adhesion test

[0388] In order to investigate the adhesion, an explanatory peel test was performed. As a peeling test, a 1mm square crack was given to the obtained sample in a checkerboard shape, an adhesive tape (manufactured by Nikkeihan Co., Ltd., Sidile (registered trademark)) was attached to the liquid crystal surface, and then the tape was peeled off and visually inspected. Observed. As a result, the adhesion degree was 100%.

[0389] Adhesion (%) = (the part without peeling/the area where the tape is attached)×100

[0390] 3. Humidity and heat resistance test-1

[0391] The sample was immersed in hot water at 90°C for 60 minutes, and the optical properties and adhesion were measured by the above-mentioned method. As a result, no changes in optical properties and adhesion were found before and after the test.

[0392] 4. Humidity and heat resistance test-2

[0393] The sample was allowed to stand for 24 hours in an environment of 80°C and a humidity of 95%, and the optical properties and adhesion were measured by the above-mentioned method. As a result, there was no change in optical properties and adhesion before and after the test. In addition, after the test, no bleeding of the refractive index anisotropic material was found, and no white turbidity was found.

[0394] 5. Water resistance test

[0395] The sample was immersed in pure water at room temperature (23.5°C) for 1 day, and the optical properties and adhesion were measured by the above-mentioned method. As a result, no changes in optical properties and adhesion were found before and after the test.

[0396] 6. Alkali resistance test

[0397] The sample was immersed in an alkaline aqueous solution (1.5N sodium hydroxide aqueous solution) at 55°C for 3 minutes, washed with water, and dried, and the optical properties and adhesiveness were measured by the above-mentioned methods. As a result, no changes in optical properties and adhesion were found before and after the test. In addition, no coloring was found.

Example Embodiment

[0398] (Example 2)

[0399] 20% by mass of the photopolymerizable liquid crystal compound (I) represented by the above formula (I) as a rod-shaped compound was dissolved in cyclohexanone and coated on an unstretched COP (cycloolefin polymer) film by bar coating (Manufactured by JSR Co., Ltd., trade name: ARTON). Then, it heated at 50 degreeC for 2 minutes, and the solvent was removed. Furthermore, the coating surface was irradiated with ultraviolet rays to immobilize the rod-like compound, and then heated at 90°C for 2 minutes to remove the residual solvent, thereby producing a retardation film. The obtained retardation film was used as a sample, and the following items were evaluated.

[0400] 1. Random uniform orientation

[0401] For the retardation layer of the produced retardation film, Re and the presence or absence of selective reflection wavelength, Rth, and haze were evaluated. The measurement was performed on the entire retardation film and the unstretched COP (cycloolefin polymer) film (manufactured by JSR Corporation, trade name: ARTON), respectively, and was performed by subtracting the measured value of the latter from the measured value of the former. Here, for the measurement of the above-mentioned Re and Rth, a product made by Oji Measuring Instruments Co., Ltd., trade name: KOBRA-21ADH was used. In addition, the Nippon Denshoku Kogyo Co., Ltd. product, brand name: NDH2000 was used for the measurement of the above-mentioned turbidity. Furthermore, for the confirmation of the presence or absence of the above-mentioned selective reflection wavelength, a product made by Shimadzu Corporation, trade name: UV-3100PC was used. As a result, the retardation layer of the produced retardation film had Rth = 106.6 nm, Re = 2.9 nm, and haze = 0.04%, and did not have a selective reflection wavelength. From this, it was confirmed that in the retardation layer of the retardation film, the said photopolymerizable liquid crystal compound was oriented randomly and uniformly.

[0402] 2. Optical characteristics

[0403] The phase difference of the sample was measured with an automatic birefringence measuring device (KOBRA-21ADH manufactured by Oji Measuring Instruments Co., Ltd.). The measurement light was incident from the oblique direction perpendicular to the surface of the sample, and it was confirmed from the graph of the optical retardation and the incident angle of the measurement light that the anisotropy of the substrate film was increased.

[0404] 3. Turbidity

[0405] In order to investigate the transparency of the sample, the turbidity was measured with a turbidity meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., trade name: NDH2000). As a result, the coating amount was 3g/m 2 , And good, 0.3% or less.

[0406] 4. Adhesion test

[0407] In order to investigate the adhesion, an explanatory peel test was performed. As a peeling test, a 1mm square crack was given to the obtained sample in a checkerboard shape, an adhesive tape (manufactured by Nikkeihan Co., Ltd., Sidile (registered trademark)) was attached to the liquid crystal surface, and then the tape was peeled off and visually inspected. Observed. As a result, the adhesion degree was 100%.

[0408] Adhesion (%) = (the part without peeling/the area where the tape is attached)×100

[0409] 5. Humidity and heat resistance test

[0410] The sample was immersed in hot water at 90°C for 60 minutes, and the optical properties and adhesion were measured by the above-mentioned method. As a result, no changes in optical properties and adhesion were found before and after the test.

[0411] 6. Water resistance test

[0412] The sample was immersed in pure water at room temperature (23.5°C) for 1 day, and the optical properties and adhesion were measured by the above-mentioned method. As a result, no changes in optical properties and adhesion were found before and after the test.

Example Embodiment

[0413] (Example 3)

[0414] 20% by mass of the photopolymerizable liquid crystal compound (I) represented by the above formula (I), which is a rod-shaped compound, was dissolved in cyclohexanone, and then coated on a uniaxially stretched COP (cycloolefin polymer) by bar coating Film (manufactured by JSR Co., Ltd., trade name: ARTON). Then, it heated at 50 degreeC for 2 minutes, and the solvent was removed. Furthermore, the coating surface was irradiated with ultraviolet rays to immobilize the rod-like compound, and then heated at 90°C for 2 minutes to remove the residual solvent, thereby producing a retardation film. The obtained retardation film was used as a sample, and the following items were evaluated.

[0415] 1. Random uniform orientation

[0416] For the retardation layer of the produced retardation film, the presence or absence of the selective reflection wavelength, Rth, and haze were evaluated. The measurement was performed on the entire retardation film and the above-mentioned uniaxially stretched COP (cycloolefin polymer) film (manufactured by JSR Co., Ltd., trade name: ARTON), and was performed by subtracting the measured value of the latter from the measured value of the former . Here, for the measurement of the above-mentioned Re and Rth, a product made by Oji Measuring Instruments Co., Ltd., trade name: KOBRA-21ADH was used. In addition, the Nippon Denshoku Kogyo Co., Ltd. product, brand name: NDH2000 was used for the measurement of the above-mentioned turbidity. Furthermore, for the confirmation of the presence or absence of the above-mentioned selective reflection wavelength, a product made by Shimadzu Corporation, trade name: UV-3100PC was used. As a result, the retardation layer of the produced retardation film had Rth=2.9 nm, Re=106.6 nm, and haze=0.04%, and did not have a selective reflection wavelength. From this, it was confirmed that in the retardation layer of the retardation film, the said photopolymerizable liquid crystal compound was oriented randomly and uniformly.

[0417] 2. Optical characteristics

[0418] The phase difference of the sample was measured with an automatic birefringence measuring device (KOBRA-21ADH manufactured by Oji Measuring Instruments Co., Ltd.). The measurement light was incident from the oblique direction perpendicular to the surface of the sample, and it was confirmed from the graph of the optical retardation and the incident angle of the measurement light that the anisotropy of the substrate film was increased. In addition, the three-dimensional refractive index was measured using the measuring device. The results are shown in Table 1 below.

[0419] [Table 1]

[0420] Nx

[0421] 3. Turbidity

[0422] In order to investigate the transparency of the sample, the turbidity was measured with a turbidity meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., trade name: NDH2000). As a result, the coating amount was 3g/m 2 , And good, 0.3% or less.

[0423] 4. Adhesion test

[0424] In order to investigate the adhesion, an explanatory peel test was performed. As a peeling test, a 1mm square crack was given to the obtained sample in a checkerboard shape, an adhesive tape (manufactured by Nikkeihan Co., Ltd., Sidile (registered trademark)) was attached to the liquid crystal surface, and then the tape was peeled off and visually inspected. Observed. As a result, the adhesion degree was 100%.

[0425] Adhesion (%) = (the part without peeling/the area where the tape is attached)×100

[0426] 5. Humidity and heat resistance test

[0427] The sample was immersed in hot water at 90°C for 60 minutes, and the optical properties and adhesion were measured by the above-mentioned method. As a result, no changes in optical properties and adhesion were found before and after the test.

[0428] 6. Water resistance test

[0429] The sample was immersed in pure water at room temperature (23.5°C) for 1 day, and the optical properties and adhesion were measured by the above-mentioned method. As a result, no changes in optical properties and adhesion were found before and after the test.

PUM

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