Antiglare film, polarizer, and image display device
10048407 ยท 2018-08-14
Assignee
Inventors
Cpc classification
B32B2307/50
PERFORMING OPERATIONS; TRANSPORTING
B32B5/16
PERFORMING OPERATIONS; TRANSPORTING
B32B2457/202
PERFORMING OPERATIONS; TRANSPORTING
B32B2307/40
PERFORMING OPERATIONS; TRANSPORTING
G09F9/30
PHYSICS
G02B5/3025
PHYSICS
International classification
B32B5/16
PERFORMING OPERATIONS; TRANSPORTING
G02F1/1335
PHYSICS
Abstract
An antiglare film in which occurrence of screen scintillation and white muddiness can be sufficiently prevented at a high level while maintaining hard coating properties and antiglare properties, and excellent display images with a high contrast can be provided. The antiglare film includes a light-transmitting substrate; and an antiglare layer having a surface roughness on at least one surface of the light-transmitting substrate, wherein the antiglare layer contains an aggregate composed of two or more types of fine particles, and the aggregate forms a projection of the surface of the antiglare layer to form a surface roughness on the antiglare layer.
Claims
1. An antiglare film comprising: a light-transmitting substrate; and an antiglare layer having a surface roughness on at least one surface of the light-transmitting substrate, wherein the antiglare layer contains an aggregate composed of two or more types of spherical fine particles in a binder resin, the aggregate forms a projection of the surface of the antiglare layer to form a surface roughness on the antiglare layer, the two or more types of spherical fine particles do not protrude from the surface of the binder resin, the two or more types of spherical fine particles include one or more types of organic fine particles and one or more types of inorganic fine particles, the organic fine particles have an average particle size of 0.3 to 10.0 m and the inorganic fine particles have an average particle size of 500 nm to 5.0 m, and the antiglare layer further contains binder particles that promote the formation of an aggregate composed of the organic fine particles and the inorganic fine particles and have a particle size of 200 nm or smaller.
2. The antiglare film according to claim 1, wherein the binder particles are unevenly distributed around the organic fine particles and the inorganic fine particles.
3. The antiglare film according to claim 1, wherein the binder particles are fumed silica.
4. The antiglare film according to claim 3, wherein the fumed silica is surface-treated.
5. The antiglare film according to claim 4, wherein the fumed silica is surface-treated by hydrophobing treatment, and the hydrophobizing treatment is methyl treatment, octylsilane treatment, or dimethyl silicone oil treatment.
6. The antiglare film according to claim 1, wherein the organic fine particles are fine particles of at least one material selected from the group consisting of acrylic resins, polystyrene resins, styrene/acrylic copolymers, polyethylene resins, epoxy resins, silicone resins, polyvinylidene fluoride resins, and polyfluoroethylene resins.
7. The antiglare film according to claim 1, wherein the inorganic fine particles are at least one type of fine particles selected from the group consisting of particles of aluminosilicate, talc, mica, and silica.
8. A polarizer comprising a polarizing element, wherein the polarizer comprises the antiglare film according to claim 1, on a polarizing element surface.
9. An image display device comprising the antiglare film according to claim 1, or a polarizer comprising a polarizing element, wherein the polarizer comprises the antiglare film according to claim 1 on a polarizing element surface, on an outermost surface thereof.
10. The antiglare film according to claim 1, wherein the organic particles are present in an amount of 0.5 to 15% by mass.
11. The antiglare film according to claim 1, wherein the organic particles are present in an amount of 2 to 10% by mass.
12. The antiglare film according to claim 1, wherein the inorganic particles are present in an amount of 0.1 to 10% by mass.
13. The antiglare film according to claim 1, wherein the inorganic particles are present in an amount of 0.5 to 7% by mass.
14. The antiglare film according to claim 1, wherein the inorganic particles are configured to be placed among and below the organic fine particles in the aggregate.
15. The antiglare film according to claim 1, which has a haze value of less than 20%.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
DESCRIPTION OF EMBODIMENTS
(7) The present invention will be described by means of the following examples which, however, are not intended to limit the scope of the present invention. The terms part(s) and % are based on mass unless otherwise stated.
Example 1
(8) A light-transmitting substrate (an 80-m-thick triacetyl cellulose resin film, TD 80UL, product of Fujifilm Corporation) was prepared. A composition for an antiglare layer with the formulation shown below was applied to one side of the light-transmitting substrate to prepare a coating. Then, the formed coating was dried for 60 seconds in a hot oven at 50 C. to evaporate the solvent in the coating. The coating was cured with ultraviolet light until the accumulated light quantity reaches 50 mJ/cm.sup.2, and thereby formed into a 4-m-thick antiglare layer (after cured). Thus, an antiglare film in accordance with Example 1 was prepared.
(9) (Composition for Antiglare Layer)
(10) Organic fine particles (acrylic/styrene copolymer particles, average particle size of 2.0 m, refractive index of 1.515, product of Sekisui Plastics Co., Ltd.) 1 part by mass
(11) Spherical inorganic fine particles (aluminosilicate particles, average particle size of 2.0 m, refractive index of 1.50, product of MIZUSAWA INDUSTRIAL CHEMICALS, LTD.) 3 parts by mass
(12) Fumed silica (AEROSIL R805, average particle size of 12 nm, product of Nippon Aerosil Co., Ltd.) 1 part by mass
(13) Pentaerythritoltriacrylate (PETA, product of DAICEL-CYTEC Company LTD.) 60 parts by mass
(14) Urethane acrylate (UV1700B, product of The Nippon Synthetic Chemical Industry Co., Ltd.) 40 parts by mass
(15) Irgacure 184 (product of BASF Japan Ltd.) 6 parts by mass
(16) Irgacure 907 (product of BASF Japan Ltd.) 1 part by mass
(17) Polyether-modified silicone (TSF4460, product of Momentive Performance Materials Inc.) 0.025 parts by mass
(18) Toluene 105 parts by mass
(19) Isopropyl alcohol 30 parts by mass
(20) Cyclohexanone 15 parts by mass
(21) The fumed silica was surface-treated with a silane coupling agent containing a methyl group.
Example 2
(22) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 5 parts by mass. An antiglare film according to Example 2 was produced as in Example 1 except that this composition for an antiglare layer was used.
Example 3
(23) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 12 parts by mass. An antiglare film according to Example 3 was produced as in Example 1 except that this composition for an antiglare layer was used.
Example 4
(24) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 5 parts by mass and the amount of the inorganic fine particles was 0.3 parts by mass. An antiglare film according to Example 4 was produced as in Example 1 except that this composition for an antiglare layer was used.
Example 5
(25) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 5 parts by mass and the amount of the inorganic fine particles was 8 parts by mass. An antiglare film according to Example 5 was produced as in Example 1 except that this composition for an antiglare layer was used.
Example 6
(26) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 5 parts by mass and the amount of the fumed silica was 0.3 parts by mass. An antiglare film according to Example 6 was produced as in Example 1 except that this composition for an antiglare layer was used.
Example 7
(27) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 5 parts by mass and the amount of the fumed silica was 4 parts by mass. An antiglare film according to Example 7 was produced as in Example 1 except that this composition for an antiglare layer was used.
Example 8
(28) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 5 parts by mass and 1 part by mass of fumed silica (average particle size of 12 nm, product of Nippon Aerosil Co., Ltd., surface-treated with a silane coupling agent containing octylsilane) was used. An antiglare film according to Example 8 was produced as in Example 1 except that this composition for an antiglare layer was used.
Example 9
(29) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 5 parts by mass and no fumed silica was blended. An antiglare film according to Example 9 was produced as in Example 1 except that this composition for an antiglare layer was used.
Comparative Example 1
(30) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 5 parts by mass and no inorganic fine particles were blended. An antiglare film according to Comparative Example 1 was produced as in Example 1 except that this composition for an antiglare layer was used
Comparative Example 2
(31) A composition for an antiglare layer was prepared as in Example 1 except that no organic fine particles were blended. An antiglare film according to Comparative Example 2 was produced as in Example 1 except that this composition for an antiglare layer was used.
Comparative Example 3
(32) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 10 parts by mass and no inorganic fine particles and no fumed silica were blended. An antiglare film according to Comparative Example 3 was produced as in Example 1 except that this composition for an antiglare layer was used.
Comparative Example 4
(33) A composition for an antiglare layer was prepared as in Example 1 except that no organic fine particles were blended and 3 parts by mass of silica (average particle size of 2.0 m, product of Tosoh Silica Corporation) was blended as the inorganic fine particles. An antiglare film according to Comparative Example 4 was produced as in Example 1 except that this composition for an antiglare layer was used.
Comparative Example 5
(34) A composition for an antiglare layer was prepared as in Example 1 except that surface-untreated, i.e., hydrophilic AEROSIL 130 (product of Nippon Aerosil Co., Ltd., a pH of 4.0 to 4.5, a specific surface area of 130 m2/g) with an average particle size of 16 nm was used instead of the fumed silica. However, gelation and precipitation of the composition for an antiglare layer were caused at an early stage, which results in failure of the formation of an antiglare layer.
Reference Example 1
(35) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 5 parts by mass and 3 parts by mass of amorphous aluminosilicate (average particle size of 2.0 m, product of MIZUSAWA INDUSTRIAL CHEMICALS, LTD.) was used as the inorganic fine particles. An antiglare film according to Reference Example 1 was produced as in Example 1 except that this composition for an antiglare layer was used.
Reference Example 2
(36) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 18 parts by mass. An antiglare film according to Reference Example 2 was produced as in Example 1 except that this composition for an antiglare layer was used.
Reference Example 3
(37) A composition for an antiglare layer was prepared as in Example 1 except that the amount of the organic fine particles was 5 parts by mass and the amount of the inorganic fine particles was 12 parts by mass. An antiglare film according to Reference Example 3 was produced as in Example 1 except that this composition for an antiglare layer was used.
Reference Example 4
(38) A composition for an antiglare layer was prepared as in Example 1 except that acrylic/styrene copolymer particles (average particle size of 1.0 m, refractive index of 1.515, product of Sekisui Plastics Co., Ltd.) was used as the organic fine particles in an amount of 10 parts by mass and amorphous aluminosilicate particles (average particle size of 0.5 m, refractive index of 1.50, product of MIZUSAWA INDUSTRIAL CHEMICALS, LTD.) was used as the inorganic fine particles in an amount of 7 parts by mass. An antiglare film according to Reference Example 4 was produced as in Example 1 except that this composition for an antiglare layer was used and the thickness thereof after cured was set to 1.5 m.
Reference Example 5
(39) A composition for an antiglare layer was prepared as in Example 1 except that acrylic/styrene copolymer particles (average particle size of 10.0 m, refractive index of 1.515, product of Sekisui Plastics Co., Ltd.) was used as the organic fine particles in an amount of 5 parts by mass, amorphous aluminosilicate particles (average particle size of 5 m, refractive index of 1.50, product of MIZUSAWA INDUSTRIAL CHEMICALS, LTD.) was used as the inorganic fine particles in an amount of 3 parts by mass, and the amount of the fumed silica was 2 parts by mass. An antiglare film according to Reference Example 5 was produced as in Example 1 except that this composition for an antiglare layer was used and the thickness thereof after cured was set to 15.0 m.
(40) The antiglare films in accordance with Examples 1 to 9, Comparative Examples 1 to 5, and Reference Examples 1 to 5 were evaluated based on the following items. Table 1 shows the evaluation results.
(41) (Coating Liquid Stability)
(42) After an antiglare film was prepared, coating liquid stability was evaluated as Good in cases where no precipitate was present in a coating liquid tank; coating liquid stability was evaluated as Acceptable in cases where no foreign matter was present in an antiglare layer, but a precipitate was present in a tank; and coating liquid stability was evaluated as Poor in cases where a foreign matter was present in an antiglare layer and a precipitate was present in a tank.
(43) (Antiglare Properties)
(44) The antiglare properties of the resulting antiglare film were evaluated based on the following criteria by visual observation of a specimen prepared by stacking a black acrylic plate and an evaluation film with a transparent adhesive agent disposed therebetween (the adhesive faces the uncoated face) in a bright room.
(45) Good: No reflection of surroundings was observed.
(46) Poor: Reflection of surroundings was distinctly observed.
(47) (Evaluation of Gloss Blackness in a Bright Room: Whether the Appearance is Glossy Black without White Muddiness)
(48) The white muddiness of the resulting antiglare film was evaluated based on the following criteria by visual observation of a specimen prepared by stacking a black acrylic plate and an evaluation film with a transparent adhesive agent disposed therebetween (the adhesive faces the uncoated face) in a bright room.
(49) Excellent: The surface had no white muddiness, and gloss blackness in a bright room was very good.
(50) Good: The surface had no white muddiness, and gloss blackness in a bright room is good.
(51) Poor: The surface totally had white muddiness.
(52) (Screen Scintillation Evaluation)
(53) The antiglare properties of the resulting antiglare film were evaluated based on the following criteria by visual observation of a laminate of a light box, a black matrix glass with 140 ppi disposed on the box, and an evaluation film disposed on the glass.
(54) Excellent: Screen scintillation was hardly observed.
(55) Good: Screen scintillation was sufficiently suppressed.
(56) Poor: No preventive effect of screen scintillation was observed.
(57) (Evaluation of Gloss Blackness in a Dark Room: Contrast Ratio in a Dark Room)
(58) In a dark room, a cool cathode fluorescent tube light source and a diffusion plate disposed therewith as a backlight unit and two polarizers (AMN-3244TP, product of Samsung) were used. The luminance (L.sub.max), at the front face, of light passed through the polarizers arranged in parallel Nicol was divided by the luminance (L.sub.min), at the front face, of light passed through the crossed Nicols polarizers to determine the contrast (L.sub.1) of an antiglare film (light-transmitting substrate+antiglare layer) and the contrast (L.sub.2) of a light-transmitting substrate. A contrast ratio was calculated by (L.sub.1/L.sub.2)100(%).
(59) The luminance was measured with a luminance colorimeter (BM-5A, product of TOPCON CORP.). The measurement angle of the luminance colorimeter was set to 1 and the visual field on a sample was set to 5 mm. With respect to the quantity of light from the backlight, two polarizers were arranged in parallel nicol without setting a sample so as to provide luminance of 3600 cd/m.sup.2.
(60) An antiglare film with a contrast ratio exceeding 90 was evaluated as a film having high contrast and excellent gloss blackness in a dark room. An antiglare film with a contrast ratio exceeding 80 and 90 or less was evaluated as a film having high contrast and good gloss blackness in a dark room. An antiglare film with a contrast ratio of 80 or less was evaluated as a film having low contrast and no gloss blackness in a dark room.
(61) (Pencil Hardness)
(62) The moisture content of the resulting antiglare film was controlled for 2 hours at a temperature of 25 C. and relative humidity of 60%. The antiglare film was subjected to a pencil hardness test (500 g of load) prescribed in JIS K5600-5-4 (1999) using a test pencil specified in JIS-S-6006. The highest hardness providing no scratch was determined.
(63) (Crack)
(64) In accordance with a mandrel test (a test in which a sample is wound around a metal cylinder) described in DIS-K 5600-5-1, the resulting antiglare film was wound around a 8-mm mandrel bar in the longitudinal direction with the antiglare layer facing outward, and the generation of a crack was evaluated.
(65) A film uncracked was evaluated as Good. A film cracked was evaluated as Poor.
(66) (Average Distance (Sm) Between a Projection and a Depression; Arithmetic Mean Roughness (Ra) of an Projections and Depressions; Average Tilt Angle (a) of Projections and Depressions; and 10-Point Mean Roughness (Rz))
(67) With respect to an antiglare film with a surface roughness, the average distance (Sm) between a projection and a depression; arithmetic mean roughness (Ra) of projections and depressions; and 10-point mean roughness (Rz) were measured according to JIS B 0601-1994, and an average tilt angle (a) of projections and depressions was measured by the method shown in
(68) (1) Probe of surface roughness detection part:
(69) Model/SE2555N (2 probe), product of Kosaka Laboratory Ltd.
(70) (tip curvature radius 2 m/apex: 90 degrees/material: diamond)
(71) (2) Measurement conditions of surface roughness measurement device:
(72) Standard length (cut-off value of roughness curve c: 2.5 mm
(73) Evaluation length (standard length (cut-off value c)5): 12.5 mm
(74) Probe sending speed: 0.5 mm/s
(75) The cut-off value is usually set at 0.8 mm, but in the present invention, the cut-off value is set at 2.5 mm for the measurement. The reason for this as follows: the surface roughness on the antiglare film of the present invention preferably has a shape that enables to prevent reflection of natural light and provide a black display of an image display device excellent in gloss blackness (reproducibility of luster black color as if wetted in screen display) as described above. That is, a large and gentle surface roughness is preferable, and in order to measure this surface roughness, the cut-off value is preferably set at 2.5 mm for the measurement.
(76) (Aggregation State of Fine Particles)
(77) The cross-section of the antiglare film was observed with STEM at a magnification of 2000 times to 30000 times. An aggregate formed of organic fine particles and inorganic fine particles was evaluated as Good. Anything other than that was evaluated as Poor.
(78) TABLE-US-00001 TABLE 1 Gloss blackness Gloss blackness in dark room: in bright room: Film Unevenness of surface contrast in Anti-glare white thickness Sm Ra a Rz dark room properties muddiness Example 1 4.0 355.5 0.0788 0.155 0.422 99 Good Excellent Example 2 4.0 250.0 0.0970 0.210 0.539 98 Good Excellent Example 3 4.0 215.5 0.1432 0.346 0.818 95 Good Good Example 4 4.0 260.6 0.0950 0.198 0.505 99 Good Excellent Example 5 4.0 202.1 0.1410 0.401 0.853 95 Good Good Example 6 4.0 305.6 0.0855 0.177 0.488 96 Good Excellent Example 7 4.0 203.3 0.1488 0.388 0.899 96 Good Good Example 8 4.0 240.2 0.1122 0.274 0.669 96 Good Excellent Example 9 4.0 390.3 0.0692 0.105 0.353 97 Good Excellent Comparative 4.0 505.5 0.0602 0.068 0.321 99 Poor Excellent Example 1 Comparative 4.0 540.2 0.0577 0.061 0.306 99 Poor Excellent Example 2 Comparative 4.0 105.6 0.3512 1.541 1.532 80 Good Poor Example 3 Comparative 4.0 160.4 0.2740 1.254 1.286 81 Good Poor Example 4 Comparative Example 5 Reference 4.0 237.8 0.1049 0.246 0.588 78 Good Good Example 1 Reference 4.0 136.4 0.3111 1.326 1.402 88 Good Poor Example 2 Reference 4.0 162.1 0.2896 1.265 1.278 90 Good Poor Example 3 Reference 1.5 220.4 0.1377 0.354 0.788 97 Good Good Example 4 Reference 15.0 382.1 0.0745 0.189 0.466 93 Good Good Example 5 Aggregation Coating Surface Pencil state of liquid Scintillation hardness Crack particles stability Example 1 Excellent 2H Good Good Good Example 2 Good 2H Good Good Good Example 3 Good 2H Good Good Good Example 4 Good 2H Good Good Good Example 5 Good 2H Good Good Good Example 6 Excellent 2H Good Good Good Example 7 Good 2H Good Good Good Example 8 Good 2H Good Good Good Example 9 Excellent 2H Good Good Acceptable Comparative Excellent 2H Good Poor Good Example 1 Comparative Excellent 2H Good Poor Good Example 2 Comparative Good 2H Good Poor Acceptable Example 3 Comparative Poor 2H Good Poor Good Example 4 Comparative Poor Example 5 Reference Good 2H Good Poor Good Example 1 Reference Poor 2H Good Poor Good Example 2 Reference Poor 2H Good Poor Good Example 3 Reference Good H Good Good Good Example 4 Reference Good 3H Poor Good Good Example 5
(79) Table 1 shows that all the antiglare films in accordance with the examples have a high contrast ratio in a dark room, and have excellent antiglare properties, properties of preventing white muddiness, properties of preventing screen scintillation, and hard coating properties (pencil hardness and crack).
(80) The antiglare films according to the examples in which properties of preventing white muddiness is evaluated as Excellent have surface haze values in the range of 0.1% or more and less than 2% and haze values owing to internal diffusion in the range of 2% or more and less than 5%.
(81) On the other hand, both the antiglare films according to Comparative Examples 1 and 2 have less antiglare properties.
(82) The antiglare film according to Comparative Example 3 in which the antiglare layer contains no inorganic fine particles is poor in properties of preventing white muddiness. The antiglare film according to Comparative Example 4 in which the antiglare layer contains no organic fine particles is poor in properties of preventing white muddiness and properties of preventing screen scintillation.
(83) The antiglare film according to Reference Example 1 shows less contrast in a dark room because the inorganic fine particles are amorphous aluminosilicate. The antiglare film according to Reference Example 2 is poor in properties of preventing white muddiness and properties of preventing screen scintillation because of too large an amount of organic fine particles. The antiglare film according to Reference Example 3 is poor in properties of preventing white muddiness and properties of preventing screen scintillation because of too large an amount of inorganic fine particles. The antiglare film according to Reference Example 4 shows poor results of the pencil hardness test because of the small thickness of the antiglare layer. The antiglare film according to Reference Example 5 is poor in resistance to crack because of the large thickness of an antiglare layer.
(84) A composition for a low refractive index layer with the following formulation was applied to the surface of the antiglare layer of each of the antiglare films obtained in the examples so as to be a film with a thickness of 0.1 m after drying (40 C.1 minute). The film was cured by ultraviolet radiation with a radiation dose of 100 mJ/cm.sup.2 using ultraviolet radiation apparatus (light source H bulb, product of Fusion UV Systems Japan KK.). Thus, a low refractive index layer was produced. An antiglare film having the resulting low refractive index layer was excellent in white muddiness prevention effects.
(85) (Composition for Low Refractive Index Layer)
(86) Hollow silica fine particles (solid content of the silica fine particles: 20% by mass, solution: methyl isobutyl ketone, average particle size: 50 nm) 40 parts by mass
(87) Pentaerythritol triacrylate (PETA) (product of DAICEL-CYTEC Company LTD.) 10 parts by mass
(88) Polymerization initiator (Irgacure 127: product of BASF Japan Ltd.) 0.35 parts by mass
(89) Modified silicone oil (X22164E: product of Shin-Etsu Chemical Co., Ltd.) 0.5 parts by mass
(90) MIBK 320 parts by mass
(91) PGMEA 161 parts by mass
INDUSTRIAL APPLICABILITY
(92) The antiglare film of the present invention can be suitable for cathode-ray tube (CRT) display devices, liquid crystal displays (LCD), plasma display panels (PDP), electroluminescence displays (ELD), field-emission displays (FED), touch panels, electronic paper displays, tablet computers, and the like.