LIGHT-BLOCKING MATERIAL FOR OPTICAL DEVICES, AND PRODUCTION METHOD THEREFOR

Abstract

Provided is a method for producing a light-blocking material for optical devices which is provided with a light-blocking coat achieving low gloss while maintaining the necessary physical properties of a light-blocking coat, i.e. a light-blocking property, even when the light-blocking coat is formed extremely thinly. In the method for producing the light-blocking material for optical devices which is provided with the light-blocking coat, a coating liquid including at least a binder resin, black microparticles, and a dye is prepared. A dye including a metal such as chrome oxide, iron oxide, or cobalt oxide is preferably used as the dye. The coating liquid is subsequently applied to a base material, and dried to form the light-blocking coat.

Claims

1. A method for producing a light-blocking material for optical devices provided with a light-blocking film, the method comprising the steps of preparing a coating liquid including at least a binder resin, black microparticles and a dye, applying the coating liquid to a substrate and drying to form a light-blocking film.

2. The method for producing a light-blocking material for optical devices according to claim 1, wherein a dye including a metal is used as the dye.

3. The method for producing a light-blocking material for optical devices according to claim 2, wherein those including at least either one of chrome oxide, iron oxide and cobalt oxide are used as the dye.

4. The method for producing a light-blocking material for optical devices according to claim 3, wherein the dye is blended in a range of 1 part by weight or greater and 30 parts by weight or less with respect to 100 parts by weight of a binder resin in the coating liquid.

5. The method for producing a light-blocking material for optical devices according to claim 4, wherein a light-blocking film is formed to have a thickness of 6 m or less.

6. The method for producing a light-blocking material for optical devices according to claim 5, wherein a coating liquid furthermore including a matting agent in an amount of 0.2 part by weight or greater and 10 parts by weight or less with respect to 100 parts by weight of a binder resin is used.

7. A light-blocking material for optical devices provided with a light-blocking film including at least a binder resin and black microparticles, wherein the light-blocking film is formed by using a coating liquid including a dye together with the binder resin and black microparticles and specular gloss thereof at 60 degrees is adjusted to be less than 4%.

8. A coating liquid for forming light-blocking films, which is a coating liquid for forming a light-blocking film provided to a light-blocking material for optical devices, wherein the coating liquid includes at least a binder resin, black microparticles, a dye and a solvent.

9. The method for producing a light-blocking material for optical devices according to claim 1, wherein the dye is blended in a range of 1 part by weight or greater and 30 parts by weight or less with respect to 100 parts by weight of a binder resin in the coating liquid.

10. The method for producing a light-blocking material for optical devices according to claim 2, wherein the dye is blended in a range of 1 part by weight or greater and 30 parts by weight or less with respect to 100 parts by weight of a binder resin in the coating liquid.

11. The method for producing a light-blocking material for optical devices according to claim 1, wherein a light-blocking film is formed to have a thickness of 6 m or less.

12. The method for producing a light-blocking material for optical devices according to claim 2, wherein a light-blocking film is formed to have a thickness of 6 m or less.

13. The method for producing a light-blocking material for optical devices according to claim 3, wherein a light-blocking film is formed to have a thickness of 6 m or less.

14. The method for producing a light-blocking material for optical devices according to claim 1, wherein a coating liquid furthermore including a matting agent in an amount of 0.2 part by weight or greater and 10 parts by weight or less with respect to 100 parts by weight of a binder resin is used.

15. The method for producing a light-blocking material for optical devices according to claim 2, wherein a coating liquid furthermore including a matting agent in an amount of 0.2 part by weight or greater and 10 parts by weight or less with respect to 100 parts by weight of a binder resin is used.

16. The method for producing a light-blocking material for optical devices according to claim 3, wherein a coating liquid furthermore including a matting agent in an amount of 0.2 part by weight or greater and 10 parts by weight or less with respect to 100 parts by weight of a binder resin is used.

17. The method for producing a light-blocking material for optical devices according to claim 4, wherein a coating liquid furthermore including a matting agent in an amount of 0.2 part by weight or greater and 10 parts by weight or less with respect to 100 parts by weight of a binder resin is used.

Description

EXAMPLES

[0061] Below, the present invention will be explained furthermore with examples. Note that part and % are based on weight unless otherwise mentioned.

1. Preparation of Light-Blocking Material Samples

Experimental Examples 1-1 to 8-3

[0062] A black PET film having a thickness of 25 m (Lumirror X30: Toray Industries, Inc.) was used as a substrate, and coating liquids a to h of the formulas below were applied respectively on both surfaces thereof by using a bar coating method. Contents (parts in terms of solid content) of acryl polyol, etc. in respective coating liquids are shown in Table 2. The respective coating liquids were all prepared to have a solid content of 13.5%.

[0063] After that, light-blocking coats A1 to H3 were formed after drying, so that light-blocking material samples of respective experimental examples were produced. Adhesion amounts of respective coating liquids are shown in Table 3 below.

[0064] <Formulas of Coating Liquids a to h for Forming Light-blocking coat>

TABLE-US-00002 * acryl polyol (solid content 50%) 153.8 parts (ACRYDIC A807: DIC Corporation) * isocyanate (solid content 75%) 30.8 parts (BURNOCK DN980: DIC Corporation) * carbon black (average particle diameter 25 nm) 24 parts (TOKABLACK #5500: Tokai Carbon Co., Ltd.) * dye listed in Table 1 (not included in coating parts listed in liquid h) Table 1 * matting agent (average particle diameter 2.0 m) 5 parts * methyl ethyl ketone and toluene 745.16 to 934.18 parts

TABLE-US-00003 TABLE 2 Material Name (part, solid content) Binder Resin Dye (Resin Content) Absorbable Coating Acryl Carbon Matting Wavelength Liquid Polyol Isocyanate Total Black Agent X1 X2 X3 X4 Color Range (nm) a 76.9 23.1 100 24 5 0.5 Black 380-750 b 1.8 Black 380-750 c1 5 Black 380-750 c2 14 Black 380-750 c3 16 Black 380-750 c4 30 Black 380-750 d 31 Black 380-750 e 1.2 Blue 450-495 f 5 5 Green 450-590 g 5 5 Purple 450-750 h

[0065] Note that, in Table 2, dye X1 is a black dye composed of Sol. Black 27 and absorbs a ray having a wavelength range of 380 to 750 nm (product name: Black C-832 produced by Chuo synthetic Chemical Co., Ltd.), dye X2 is a blue dye composed of Sol. Blue 44 and absorbs a ray having a wavelength range of 450 to 495 nm (product name: Blue 44 C-531 produced by Chuo synthetic Chemical Co., Ltd.), dye X3 is a red dye composed of Sol. Red 218 and absorbs a ray having a wavelength range of 620 to 750 nm (product name: Red C-431 produced by Chuo synthetic Chemical Co., Ltd.) and dye X4 is a yellow dye composed of Sol. Yellow 21 and absorbs a ray having a wavelength range of 570 to 590 nm (product name: Yellow C-131 produced by Chuo Synthetic Chemical Co., Ltd.).

2. Evaluation

[0066] The obtained light-blocking material samples obtained in the respective experimental examples were evaluated on physical properties by the methods below. The results are shown in Table 3. Note that Table 3 also shows application amounts of coating liquids in Table 1 and film thicknesses of formed light-blocking coats, etc.

[0067] Note that evaluation of a light-blocking property in (1) below was made by using samples formed by applying respective coating liquids of formulas in the respective experimental examples above in an adhesion amount of 14 g/m.sup.2 on one surface of a transparent polyethylene terephthalate film (Lumirror T60: Toray Industries, Inc.) having a thickness of 25 m and drying.

(1) Evaluation on Light-Blocking Property Optical transmission densities of samples in respective experimental examples were measured based on JIS-K7651:1988 by using an optical densitometer (TD-904: Gretag Macbeth) to evaluate a light-blocking property based on the references below. Note that a UV filter was used in the optical density measurement.
: Optical transmission density exceeded 4.0 (excellent).
x: Optical transmission density was 4.0 or less (defective).

(2) Evaluation on Conductivity

[0068] Surface resistivity () of light-blocking material samples obtained in the respective experimental examples was measured based on JIS-K6911:1995 and conductivity was evaluated based on the references below.

: Surface resistivity was 1.010.sup.6 or less (excellent).
: Surface resistivity exceeded 1.010.sup.6 and 1.010.sup.10 or less (preferable).
x: Surface resistivity exceeded 1.010.sup.10 (defective).

(3) Evaluation of Delustering Property

[0069] On the light-blocking material samples obtained in the respective experimental examples, specular gloss (unit: %) at 60 degrees (G60) on the light-blocking coat surfaces was measured based on JIS-Z8741:1997 by using a glossimeter (product name: VG-2000, Nippon Denshoku Industries Co., Ltd.) and evaluated based on the references below. Specular gloss (unit: %) at 20 degrees and 85 degrees (G20 and G85) was also measured in addition to G60 and evaluated based on the references below.

[0070] It was observed that the smaller the respective measurement values in G20, G60 and G85 were, the lower the glossiness was, and that the lower the glossiness, the more excellent in a delustering property.

[G60]

[0071] : Glossiness was less than 4% (very excellent).
: Glossiness was 4% or more and less than 10% (excellent).
: Glossiness was 10% or more and less than 15% (preferable).
x: Glossiness was 15% or more (defective).

[G20]

[0072] : Glossiness was less than 0.1% (very excellent).
: Glossiness was 0.1% or more and less than 0.5% (excellent).
: Glossiness was 0.5% or more and less than 1% (preferable).
x: Glossiness was 1% or more (defective).

[G85]

[0073] : Glossiness was less than 20% (very excellent).
: Glossiness was 20% or more and less than 25% (excellent).
: Glossiness was 25% or more and less than 30% (preferable).
x: Glossiness was 30% or more (defective).

TABLE-US-00004 TABLE 3 Coating Liquid Dye Blending Amount/ 100 Light-blocking parts of coat Performances Resin Adhesion Film Light- Delustering Experimental Content Amount Thickness Blocking Property example Formula (part) (g/m.sup.2) Kind (m) Property Conductivity G20 G60 G85 1-1 a 0.5 24 A1 5.5 1-2 a 28 A2 6 1-3 a 46 A3 8 2 b 1.8 14 B 5.5 3-1 C1 5 14 C1 4 3-2 C2 14 14 C2 4 3-3 C3 16 14 C3 4 3-4 C4 30 14 C4 4 4 d 30.5 14 D 4 5 e 1.2 24 E 5.5 6 f 10 14 F 4 7 g 10 14 G 4 8-1 h 0 28 H1 6 X 8-2 h 50 H2 10 X X 8-3 h 100 H3 20 X X

3. Consideration

[0074] As shown in Table 2 and Table 3, when using a coating liquid blended with a dye together with carbon black (those except for coating liquid h) (those except for experimental examples 8-1 to 8-3), usefulness of obtained light-blocking coat was confirmed (experimental examples 1-1 to 7). Among them, light-blocking coats obtained from experimental examples 2, 3-1 to 3-4 and 5 to 7 using coating liquids, wherein a blending amount of a dye with respect to 100 parts of a resin content was in a preferable range (1 to 30 parts) of the present invention, exhibited a more excellent delustering property than light-blocking coats of other experimental examples (1-1 to 1-3 and 4). Particularly, when a blending amount of a dye with respect to 100 parts of a resin content was in a more preferable range (5 to 15 parts) of the present invention (experimental examples 3-1, 3-2, 6 and 7), light-blocking coats to be obtained were furthermore excellent in the delustering property than those of other experimental examples (2, 3-3, 3-4 and 5).

[0075] On the other hand, it was confirmed that when a blending amount of a dye is zero (experimental examples 8-1 to 8-3), light-blocking coats to be obtained were not able to achieve both performances of the light-blocking property and delustering property compared with light-blocking coats of experimental examples 1-1 to 7.