COMPOSITION FOR PREPARING A COLOR FILTER

Abstract

The invention relates to a composition comprising i) A colorant ii) A radical generating photoinitiator, iii) A polymer wherein at least 40 mol-% of the repeating units are units according to formula (I), [Formula should be inserted herm] wherein R.sup.1 independently of each occurrence is H or CH.sub.3, R.sup.2 is a group of formula (II), [Formula should be inserted here] wherein L is a linking group, n is 0 or 1, and X independently of each occurrence is O or CH.sub.2, R.sup.3 independently of each occurrence is selected from H, COOH, and a group of formula (II), iv) 0.0 to 10.0% by weight, calculated on the on the weight of the polymer iii), of one or ethylenically unsaturated polymerizable monomers having a molecular weight of less than 1500 g/mol.

##STR00001##

Claims

1. A composition comprising i) a colorant ii) a radical generating photoinitiator, iii) a polymer wherein at least 40 mol-% of the repeating units are units according to the following formula (I), ##STR00009## wherein R.sup.1 independently of each occurrence is H or CH.sub.3, R.sup.2 is a group of the following formula (II), ##STR00010## wherein L is a linking group, n is 0 or 1, and X independently of each occurrence is O or CH.sub.2, R.sup.3 independently of each occurrence is selected from H, COOH, and a group of formula (II), and iv) 0.0 to 10.0% by weight, calculated on the on the weight of the polymer iii), of one or more ethylenically unsaturated polymerizable monomers having a molecular weight of less than 1500 g/mol.

2. The composition according to claim 1, wherein the composition comprises from 0.0 to 5.0% by weight, calculated on the weight of the polymer iii), of the one or more ethylenically unsaturated polymerizable monomers having a molecular weight of less than 1500 g/mol and having no alkoxysilane groups.

3. The composition according to claim 2, wherein the composition is substantially free of the one or more ethylenically unsaturated polymerizable monomers having a molecular weight of less than 1500 g/mol and having no alkoxysilane groups.

4. The composition according to claim 1, wherein the polymer iii) further comprises acid groups.

5. The composition according to claim 4, wherein the acid groups are carboxylic acid groups.

6. The composition according to claim 4, wherein polymer iii) has an acid value in the range of 65 to 170 mg KOH/g.

7. The composition according to claim 4, wherein the acid groups are linked to the polymer main chain of the polymer iii) via a linking group having at least 4 carbon atoms.

8. The composition according to claim 1, wherein the polymer iii) has a weight average molecular weight Mw in the range of 15000 to 150000 g/mol.

9. The composition according to claim 1, wherein the colorant comprises at least one of pigments and dyes.

10. The composition according to claim 1, wherein the composition is essentially free of polyfunctional thiols.

11. The composition according to claim 1, further comprising a dispersing agent for the colorant.

12. The composition according to claim 1, further comprising a compound having one or more alkoxysilane groups.

13. The composition according to claim 1, comprising i) 20.0 to 60.0% by weight of the colorant ii) 1.0 to 10.0% by weight of the radical generating photoinitiator iii) 20.0 to 70.0% by weight of h polymer wherein 40.0 to 80.0 mol-% of the repeating units are units according to the following formula (I′) ##STR00011## wherein R.sup.1 independently of each occurrence is H or CH.sub.3, R.sup.2 is a group of formula (II′) ##STR00012## wherein L is a linking group, n is 0, and X is CH.sub.2, R.sup.3 is H, and wherein the polymer has an acid value in the range of 65 to 170 mg KOH/g, iv) 0.0 to 1.5% by weight of the one or more ethylenically unsaturated polymerizable monomers having a molecular weight of less than 1500 g/mol and having no alkoxysilane groups, v) 5.0 to 20.0% by weight of a dispersant for the colorant, vi) 0.0 to 4.0% by weight of a compound having one or more alkoxysilane groups wherein the % by weight are calculated on the non-volatile content of the composition.

14. A process for preparing a color filter comprising applying the composition according to claim 1 to a substrate and curing selected areas of the applied composition by exposure to actinic radiation to create a pattern of cured and uncured areas of the applied composition.

15. The process according to claim 14, further comprising dissolving the uncured areas of the applied composition by treatment with an alkaline liquid treatment agent.

16. A color filter obtained by the process of claim 14.

17. A liquid crystal display comprising the color filter of claim 16.

18. A liquid crystal screen comprising the color filter of claim 16.

19. A color resolution device comprising the color filter of claim 16.

20. A sensor comprising the color filter of claim 16.

Description

EXAMPLES

[0076] Raw Materials Used

TABLE-US-00001 Name Description Source PGMEA 1-Methoxy-2-propylacetat, solvent Sigma Aldrich V-601 Dimethyl 2,2′-azobis(2-methylpropionate), initiator Wako Chemicals FA-512M Dicylcopentenyloxyethyl methacrylate Hitachi Chemical CD 535 Dicylcopentenyl methacrylate Sartomer NK Ester SA 2-Methacryloyloxyethyl succinate Shin-Nakamura MAA Methacrylic acid Sigma Aldrich HEMA 2-Hydroxyethyl acrylate Sigma Aldrich BzMA Benzyl methacrylate Sigma Aldrich Irgaphor Red BT- Colorant BASF CF LP-N 21169 Dispersant BYK-Chemie GmbH TAZ-110 2,4-Bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5- TCI, Europe triazine, Photo initiator OXE-02 1-[9-Ethyl-6-(2-methylbenzoyl)-9H-carbazol-3- BASF yl]ethanone 1-(O-acetyloxime), Photo initiator Dynasilane 3-Glycidyloxypropyltrimethoxysilane Evonik GLYMO

[0077] Preparation of Polymers iii)

[0078] General procedure for preparation of polymers P1 to P8

[0079] Solvent PGMEA was placed into a reaction vessel under nitrogen atmosphere and heated to 100°.

[0080] The monomer mixture and initiator dissolved in 2 g PGMEA were separately metered in over a period of 120 min. After metering, the reaction was further continued for 60 min and a second dose of initiator dissolved in 1 g PGMEA was added dropwise. After further reaction of 180 min, the reaction mixture was cooled to room temperature. The polymer prepared are summarized in Table 1 below.

TABLE-US-00002 TABLE 1 repeating NK units of Monomer Sartomer Ester Initiator Solvent Mw, formula Polymer FA-512M CD 535 SA MAA HEMA BzMA V-601 PGMEA g/mol (I) P1 19.7 g 11.6 g 0.43 g + 0.29 g 94.0 g 18368 60 mol % P2 19.7 g 11.6 g 0.14 g + 0.29 g 94.0 g 49104 60 mol % P3 19.2 g 4.2 g 0.42 g + 0.29 g 94.0 g 15960 60 mol % P4 16.0 g  4.2 g 3.7 g 0.14 g + 0.29 g 96.0 g 34471 50 mol % P5* 17.1 g 4.5 g 1.7 g 0.15 g + 0.22 g 93.0 g 69580 50 mol % P6 11.2 g  9.8 g 3.8 g 0.12 g + 0.24 g 95.0 g 35900 40 mol % P7  8.0 g 6.6 g 9.37 g 0.35 g + 0.23 g 96.0 g 16213 60 mol % P8 11.2 g 13.1 g 7.5 g 0.33 g + 0.33 g 95.0 g 24128 30 mol % *starting reaction temperature was 85° C., after 180 min subsequently increased to 100° C.

[0081] Preparation and Evaluation of Photocrosslinked Layers of Polymer P1-P8

[0082] The polymer solution was mixed with photoinitiator and PGMEA under stirring for 30 min. The solution was spun onto a pre-cleaned 1″ glass substrate at 1000 rpm. After prebake (90° C., 2 min) on a hotplate, the substrate was exposed to UV-light (100 mJ/cm.sup.2, i-line). The substrate was then placed into a beaker containing 0.5% NaOH solution with 0.2% sodium dodecyl sulfate for 60 s and washed with de-ionized water. The film retention was determined from the ratio of the layer thickness of the dry films before and after immersion in the developer bath. The layer thickness was measured with the aid of a surface profilometer (Surface Profiler 150 Veeco) by scratching the film and determining the step height. The photocrosslinked layer of comparative polymer P8 containing 30 mol % DCPD repeating units exhibits poor film retention indicating insufficient crosslinking of the polymer.

TABLE-US-00003 Polymer Photoinitiator Photoinitiator Film # solution OXE02 TAZ-110 PGMEA retention P1 5.00 g — 0.05 g 1.25 g 79% P2 5.00 g — 0.05 g 1.25 g 90% P2 5.00 g 0.05 g — 1.25 g 93% P3 5.00 g — 0.04 g — 71% P4 5.00 g — 0.05 g 1.25 g 84% P4 5.00 g 0.05 g — 1.25 g 82% P5 5.00 g — 0.04 g 1.00 g + 0.67 g 90% n-BuOH P6 5.00 g — 0.05 g 1.25 g 81% P7 5.00 g — 0.04 g — 76% P8 5.00 g — 0.05 g 1.25 g 10%

[0083] Preparation of Compositions According to the Invention

[0084] Composition 1

[0085] Preparation of Millbase MB1

[0086] 7.5 g of Irgaphor Red BT-CF, 10.0 g of polymer solution P2, 5.6 g of LPN21169, 24.4 g of PGMEA and 2.5 g of n-butanol were put together in a glass bottle. 100 g of Zirconox beads were added and a dispersion process was performed in a LAU-disperser DA S200 over a period of time 4 h at 40° C.

[0087] 20.0 g of MB1, 20.0 g of P2 and 0.32 g of photoinitiator TAZ-110 were mixed under stirring for 2 h and filtered through a 1-2 μm pore size syringe filter.

[0088] Composition 2

[0089] Preparation of Millbase MB2

[0090] 7.5 g of Irgaphor Red BT-CF, 12.5 g of polymer solution P5, 5.6 g of LPN21169, 21.9 g of PGMEA and 2.5 g of n-butanol were put together in a glass bottle. 100 g of Zirconox beads were added and a dispersion process was performed in a LAU-disperser DA S200 over a period of time 4 h at 40° C.

[0091] 20.0 g of MB2, 20.0 g of P5 and 0.32 g of photoinitiator TAZ-110 were mixed under stirring for 2 h and filtered through a 1-2 μm pore size syringe filter.

[0092] Composition 3

[0093] Preparation of Millbase MB3

[0094] 7.5 g of Irgaphor Red BT-CF, 12.5 g of polymer solution P4, 5.6 g of LPN21169, 21.9 g of PGMEA and 2.5 g of n-butanol were mixed under stirring in a double-walled stainless steel container. 100 g of Zirconox beads were added and a dispersion process was performed with a dissolver Dispermat LC30 (VMA-Getzmann) over a period of time 10 h at 40° C.

[0095] 20.0 g of MB3, 20.0 g of P4, 0.16 g of Dynasilane Glymo and 0.32 g of photoinitiator OXE02 were mixed under stirring for 2 h and filtered through a 1-2 μm pore size syringe filter.

[0096] Preparation of Color Filters

[0097] Color Filter 1

[0098] Composition 1 was spun onto a pre-cleaned 1″ glass substrate at 1000 rpm. After prebake (150° C., 2 min) on a hotplate, the substrate was covered with a shadow mask (USAF1951 resolution target) and exposed to UV-light (100 mJ/cm.sup.2, i-line). The substrate was then placed into a beaker containing 0.5% NaOH solution with 0.2% sodium dodecyl sulfate for 120 s and washed with de-ionized water. The photo-patterned substrate was finally baked at 120° C. for 5 min. A minimum line width resolution of 7 μm at a film thickness of 1.3 μm was obtained.

[0099] Color Filter 2

[0100] Composition 2 was spun onto a pre-cleaned 1″ glass substrate at 2000 rpm. After prebake (120° C., 5 min) on a hotplate, the substrate was covered with a shadow mask (USAF1951 resolution target) and exposed to UV-light (200 mJ/cm.sup.2, i-line). The substrate was then placed into a beaker containing 0.5% NaOH solution with 0.2% sodium dodecyl sulfate for 150 s and washed with de-ionized water. The photo-patterned substrate was finally baked at 120° C. for 5 min. A minimum line width resolution of 8 μm at a film thickness of 1.6 μm was obtained.

[0101] Color Filter 3

[0102] Composition 3 was spun onto a pre-cleaned 1″ glass substrate at 1500 rpm. After prebake (90° C., 2 min) on a hotplate, the substrate was covered with a shadow mask (USAF1951 resolution target) and exposed to UV-light (200 mJ/cm.sup.2, i-line). The substrate was then placed into a beaker containing 0.5% NaOH solution with 0.2% sodium dodecyl sulfate for 100 s and washed with de-ionized water. The photo-patterned substrate was finally baked at 120° C. for 5 min. A minimum line width resolution of 10 μm at a film thickness of 1.5 μm was obtained.

[0103] It has been demonstrated that the composition of the invention is very suitable for preparing color filters without using substantial amounts of low molecular weight ethylenically unsaturated polymerizable monomers.