Modified nano-silica and method for preparing the same, pigment dispersion and photosensitive resin composition

Abstract

The invention relates to the field of materials technology and provides a modified nano-silica and a method for preparing the same, a pigment dispersion and a photosensitive resin composition, so as to solve the problem that conventional nano-silica cannot crosslink with other polymeric materials, and pigment dispersions are apt to aggregate and have a poor film-forming property. The modified nano-silica according to the invention has unsaturated double bonds on the surface thereof and can crosslink with other polymeric materials, such that the pigment dispersion comprising the modified nano-silica can effectively prevent agglomeration and has a good film-forming property, and the photosensitive resin composition comprising the pigment dispersion can reduce the thermal expansion of a film made thereby, as well as the occurrence of shrinkage and collapse phenomena in the surface of the film, and enhance the heat-resistance, chemical-resistance, mechanical properties and abrasion-resistance of the film.

Claims

1. A pigment dispersion, characterized in that the pigment dispersion is prepared by dispersing a solute in a solvent and inducing a crosslinking reaction therein, and the average particle size of the solid particles in the pigment dispersion ranges from 40 nm to 100 nm; and the solute comprises: based on 100% by mass of the pigment dispersion, 1% to 5% of modified nano-silica particles which have unsaturated double bonds grafted on the surface thereof and have an average particle size in the range of 5 nm to 50 nm, 3% to 6% of a dispersant, 2% to 6% of a binder resin, 10% to 20% of pigment, and 0.1% to 0.5% of a photoinitiator.

2. The pigment dispersion according to claim 1, characterized in that the solute further comprises 0.2% to 1% of quantum dots, based on 100% by mass of the pigment dispersion.

3. The pigment dispersion according to claim 2, characterized in that the particle size of the quantum dots is in the range of 1 nm to 10 nm.

4. The pigment dispersion according to claim 1, characterized in that the dispersant is a block copolymer composed of segment(s) having affinity to the solvent and segment(s) comprising a nitrogen atom-containing functional group.

5. The pigment dispersion according to claim 4, characterized in that the block copolymer is one or more of acrylic block copolymers composed of segment(s) having affinity to the solvent and segment(s) comprising a nitrogen atom-containing functional group, polyurethane block copolymers composed of segment(s) having affinity to the solvent and segment(s) comprising a nitrogen atom-containing functional group, polyaminoamide block copolymers composed of segment(s) having affinity to the solvent and segment(s) comprising a nitrogen atom-containing functional group, polyether ester block copolymers composed of segment(s) having affinity to the solvent and segment(s) comprising a nitrogen atom-containing functional group, and aliphatic polycarboxylic acid block copolymers composed of segment(s) having affinity to the solvent and segment(s) comprising a nitrogen atom-containing functional group.

6. The pigment dispersion according to claim 1, characterized in that the pigment is one or more of azo, phthalocyanine, quinacridone, benzimidazolone, indanthrene, and dioxazine pigments.

7. The pigment dispersion according to claim 1, characterized in that the binder resin has unsaturated double bonds.

8. The pigment dispersion according to claim 7, characterized in that the binder resin is one or more of polyvinyl alcohols, hydroxypropyl celluloses, carboxymethyl celluloses, hydroxyethyl celluloses, methyl celluloses, styrene-acrylic acid resins, styrene-acrylic acid-acrylate resins, styrene-maleic half ester resins, methacrylic acid-methacrylate resins, isobutylene-maleic acid resins, rosin-modified maleic acid resins, polyvinyl pyrrolidone, polyallylamine, polyvinyl chloride, chlorinated polypropylene, and polyethylene imine, each having unsaturated double bonds.

9. The pigment dispersion according to claim 1, characterized in that the photoinitiator is one or more of benzoin and its derivatives, benzil, alkylphenone, acyl phosphorus oxides, benzophenones, thioxanthones, diaryl iodonium salts, triaryl iodonium salts, alkyl iodonium salts, and cumene ferrocene hexafluorophosphate.

10. A photosensitive resin composition, characterized by comprising: based on 100% by mass of the photosensitive resin composition, 30% to 40% of a pigment dispersion, 1.5% to 6% of an alkali-soluble resin, 2% to 5% of a polymerizable monomer, and 0.2% to 0.8% of a photoinitiator, wherein the pigment dispersion is prepared by dispersing a solute in a solvent and inducing a crosslinking reaction therein, and the average particle size of the solid particles in the pigment dispersion ranges from 40 nm to 100 nm; and wherein the solute comprises: based on 100% by mass of the pigment dispersion, 1% to 5% of a modified nano-silica particles which have unsaturated double bonds grafted on the surface thereof and have an average particle size in the range of 5 nm to 50 nm, 3% to 6% of a dispersant, 2% to 6% of a binder resin, 10% to 20% of pigment, and 0.1% to 0.5% of a photoinitiator.

11. The photosensitive resin composition according to claim 10, characterized in that the alkali-soluble resin is an acrylic copolymer, and the acid value of the acrylic copolymer is in the range of 50 to 150.

12. The photosensitive resin composition according to claim 11, characterized in that the acrylic copolymer is selected from (meth)acrylic acid/methyl (meth)acrylate copolymer, (meth)acrylic acid/benzyl (meth)acrylate copolymer, (meth)acrylic acid/2-hydroxyethyl (meth)acrylate/benzyl (meth)acrylate copolymer, (meth)acrylic acid/methyl (meth)acrylate/styrene copolymer, (meth)acrylic acid/2-hydroxyethyl (meth)acrylate/benzyl (meth)acrylate/methyl (meth)acrylate copolymer, and (meth)acrylic acid/benzyl (meth)acrylate/N-phenyl maleimide copolymer, and the acrylic copolymer has an acid value in the range of 60-120.

13. The photosensitive resin composition according to claim 10, characterized in that the polymerizable monomer is one or more of hexylphenyl carbitol acrylate, N-vinyl pyrrolidone, 2-ethylhexyl carbitol acrylate, ethyl (meth)acrylate, bisphenol A bis(acryloxyethyl) ether, pentaerythritol tetra(meth)acrylate, acrylonitrile, styrene, and vinyl acetate.

Description

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

(1) To enable a person skilled in the art to have a better understanding of the technical solutions of the present invention, the following specific embodiments of the present invention are described in detail.

(2) The average particle size described herein was measured by a laser nano particle size analyzer (ZS90, available from Malvern Instruments Co. Ltd., China).

(3) The acid value and amine value described herein were measured using a pH meter according to the titration method, respectively.

(4) The luminance described herein was measured by a color difference meter (Color i5, available from X-rite Inc., U.S.) under the following conditions: the light source is a pulsed xenon lamp, D65, the illumination ranges from 750 to 3200 Lux, and the detection power is 20 watts.

(5) The materials used in Comparative Example and Examples are described below.

(6) TABLE-US-00001 Materials Description Anthraquinone red DIC Co., Ltd., ATY-R177 pigment PR177 Indanthrene Blue RS Shanghai Yalian Pigment Chemicals Co., Ltd. Benzimidazolone Yellow Jiangxi Veco Pigment Co., Ltd., H4G PY151 Carbazole dioxazine Clariant Co., Ltd., RL COF01 Violet 19 Propylene glycol Dow Chemical Company monomethyl ether acetate 2-hydroxy-2-methyl-1- Ciba Specialty Chemicals, OXE01 phenyl acetone Dibenzoyl phenyl Hubei Xinghengkang Chemical phosphine oxide Technology Co., Ltd., photoinitiator TPO p-benzoylphenoxy Shanghai PE biochem Co., Ltd., diphenyliodonium photoinitiator IHT-PI440 hexafluorophosphate Carboxymethyl cellulose Haisheng Cellulose Derivatives Plant, Yinzhou, Ningbo City, CMC-1 Polyvinyl pyrrolidone Shanghai Westang Bio-Tech Co. Ltd., PVP-K30 Methacrylic acid/ A self-made resin, molecular weight: methyl methacrylate 9700, acid value: 37.9, solid content: copolymer 40 wt % Methacrylic acid/benzyl A customized resin, molecular weight: methacrylate/N-phenyl 26600, acid value: 86.3, solid content: maleimide copolymer 29.1 wt % Methacrylic acid/methyl BASF Corporation, Resin 611 methacrylate/styrene copolymer Methacrylic acid/benzyl Degussa Corporation, TEGO Variplus methacrylate copolymer SK Methacrylic acid/methyl A self-made resin, molecular weight: methacrylate resin 9700, acid value: 37.9, solid content: 40 wt % Acrylic acid-isobutylene- A self-made resin, molecular weight: maleic anhydride resin 17500, acid value: 39.5, solid content: 11.7 wt % Methacrylic acid/(2- A customized resin, molecular weight: hydroxyethyl methacrylate)/ 8400, acid value: 33.3, solid content: benzyl methacrylate/methyl 37.9 wt % methacrylate copolymer Hexylphenyl carbitol acrylate Sinopharm Corporation Ethyl methacrylate Sinopharm Corporation Bisphenol A type bis Hitachi Chemical Co., Ltd., FA-321M (acryloxyethyl) ether Pentaerythritol tetra(meth) Sinopharm Corporation acrylate Styrene Sinopharm Corporation

Comparative Example

(7) This comparative example provides a pigment dispersion, and a photosensitive resin composition comprising the pigment dispersion.

(8) The pigment dispersion of this comparative example was prepared by mixing a solute with solvent and inducing reaction of the resultant mixture. The average particle size of the solid particles in the pigment dispersion is 200 nm, and the solute comprises, based on 100% by mass of the pigment dispersion, 1% of commercially available modified nano-silica (JR-NS01A, Xuancheng Jing Rui new Material Co., Ltd., particle size: about 20 nm), 3% of a dispersant, 6% of a binder resin, 20% of a pigment, 0.1% of a photoinitiator, and the rest of solvent.

(9) The process for preparing the pigment dispersion comprises the steps of: weighing anthraquinone red pigment PR177 as a pigment, Disperbyk-137 as a dispersant, propylene glycol monomethyl ether acetate as a solvent, and a methacrylic acid/benzyl methacrylate copolymer as a binder resin, according to the aforesaid mass percentages, and mixing them in a disperser at a speed of 500 rpm for 1 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, and then removing the zirconium oxide beads after completion of milling, thereby obtaining a pigment-containing dispersion liquid; and adding the commercially available modified nano-silica and the initiator 2-hydroxy-2-methyl-1-phenyl acetone into the pigment-containing dispersion liquid under stirring, and inducing a crosslinking reaction, after stirring for 0.5 h, under the irradiation of a UV lamp (Double-sided Precision Exposure Machine GE-B8565, Beijing Zhengsheng Hongcheng Electronic Equipment Factory) for 30 s, thereby obtaining a pigment dispersion.

(10) The photosensitive resin composition of the comparative example comprises (mass %): 32% of the pigment dispersion as prepared above, 1.5% of an alkali-soluble resin, 0.2% of a photoinitiator, 2% of a polymerizable monomer, and the rest of solvent.

(11) The process for preparing the photosensitive resin composition comprises the steps of: weighing the pigment dispersion prepared in this comparative example, methacrylic acid/methyl methacrylate copolymer as an alkali-soluble acrylic copolymer resin (acid value: 150), hexylphenyl carbitol acrylate as a polymerizable monomer, and propylene glycol monomethyl ether acetate as a solvent, according to the aforesaid mass percentages, and mixing them in a ball mill at a speed of 500 rpm for 3 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, then removing the zirconium oxide beads after completion of milling, and then adding the photoinitiator, 2-thiobenzothiazole.

(12) The resultant photosensitive resin composition was coated onto a transparent glass substrate provided with a black matrix. After a photoetching process including exposure for 20 s, development and so on, a color layer (i.e., a photoresist layer) of a color filter was obtained. The appearance of the photoresist layer was inspected, and the results are shown in Table 1.

(13) A display panel comprising the color filter was prepared, and further was packaged in a display device. The brightness of the display device was tested at 20 watts, and the results are shown in Table 1.

Example 1

(14) This example provides modified nano-silica particles and a method of preparing the same, as well as a pigment dispersion and a photosensitive resin composition comprising the same.

(15) The modified nano-silica particles provided in this example have unsaturated double bonds grafted on the surface thereof, and have an average particle size of 5 nm.

(16) The method for preparation of the aforesaid modified nano-silica particles comprises the following steps: 1) the step of reacting to produce a nano-silica precursor: weighing 40 parts by mass of anhydrous ethanol, 5 parts by mass of deionized water, 6 parts by mass of 25% (v/v) ammonia, and 3 parts by mass of vinyl trimethoxy silane, and mixing them uniformly in a four-necked flask, then raising the temperature of the resultant mixture to 60 C., then slowly adding dropwise into the flask 15 parts by mass of tetraethyl orthosilicate over 2 h, and continuing the reaction for 11 h after completion of the addition, thereby obtaining the nano-silica precursor; and 2) the step of aging the nano-silica precursor: transferring the nano-silica precursor obtained in Step 1) to a thermostatic reactor and aging for 8 h at 160 C., and then filtering the resultant precipitate, washing the cake three times with ethanol and drying it in vacuo, thereby obtaining modified nano-silica particles.

(17) The pigment dispersion of this example was prepared by mixing a solute with solvent and inducing a crosslinking reaction therein. The average particle size of the solid particles in the pigment dispersion is 50 nm, and the solute comprises, based on 100% by mass of the pigment dispersion, 1% of the modified nano-silica, 3% of a dispersant, 6% of a binder resin, 20% of a pigment, 0.1% of a photoinitiator, and the rest 69.9% of solvent.

(18) The process for preparing the pigment dispersion comprises the steps of: weighing anthraquinone red pigment PR177 as a pigment, Disperbyk-137 as a dispersant, propylene glycol monomethyl ether acetate as a solvent, and a methacrylic acid/benzyl methacrylate copolymer as a binder resin, according to the aforesaid mass percentages, and mixing them in a disperser at a speed of 500 rpm for 1 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, and then removing the zirconium oxide beads after completion of milling, thereby obtaining a pigment-containing dispersion liquid; and adding the modified nano-silica of this example and the initiator 2-hydroxy-2-methyl-1-phenyl acetone into the pigment-containing dispersion liquid under stirring, and inducing a crosslinking reaction, after stirring for 0.5 h, under the irradiation of a UV lamp (GE-B8565) for 30 s, thereby obtaining a pigment dispersion.

(19) The photosensitive resin composition of this example comprises (mass %): 32% of the pigment dispersion as prepared above, 1.5% of an alkali-soluble resin, 0.2% of a photoinitiator, 2% of a polymerizable monomer, and the rest of solvent.

(20) The process for preparing the photosensitive resin composition comprises the steps of: weighing the pigment dispersion prepared in this example, methacrylic acid/methyl methacrylate copolymer as an alkali-soluble acrylic copolymer resin (acid value: 150), hexylphenyl carbitol acrylate as a polymerizable monomer, and propylene glycol monomethyl ether acetate as a solvent, according to the aforesaid mass percentages, and mixing them in a ball mill at a speed of 500 rpm for 3 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, then removing the zirconium oxide beads after completion of milling, and then adding the photoinitiator, 2-thiobenzothiazole.

(21) The resultant photosensitive resin composition was coated onto a transparent glass substrate provided with a black matrix. After a photoetching process including exposure for 20 s, development and so on, a color layer (i.e., a photoresist layer) of a color filter was obtained. The appearance of the photoresist layer was inspected, and the results are shown in Table 1.

(22) A display panel comprising the color filter was prepared, and further was packaged in a display device. The brightness of the display device was tested at the same power as the Comparative Example, and the results are shown in Table 1.

Example 2

(23) This example provides modified nano-silica particles and a method of preparing the same, as well as a pigment dispersion and a photosensitive resin composition comprising the same.

(24) The modified nano-silica particles provided in this example have unsaturated double bonds grafted on the surface thereof, and have an average particle size of 10 nm.

(25) The method for preparation of the aforesaid modified nano-silica particles comprises the following steps: 1) the step of reacting to produce a nano-silica precursor: dissolving quantum dots (CdTe, particle size: 10 nm) in anhydrous ethanol to form a solution of the quantum dots; and

(26) weighing 20 parts by mass of anhydrous ethanol, 2 parts by mass of deionized water, 2 parts by mass of 25% (v/v) ammonia, 10 parts by mass of vinyl trichlorosilane, and predetermined amount of the quantum dots solution (based on the mass of the modified nano-silica finally obtained, the amount of the quantum dots being 5%), and mixing them uniformly in a four-necked flask, then raising the temperature of the resultant mixture to 80 C., then slowly adding dropwise into the flask 20 parts by mass of tetraethyl orthosilicate over 2.5 h, and continuing the reaction for 6 h after completion of the addition, thereby obtaining the nano-silica precursor; and 2) the step of aging the nano-silica precursor: transferring the nano-silica precursor obtained in Step 1) to a thermostatic reactor and aging for 12 h at 120 C., and then filtering the resultant precipitate, washing the cake three times with ethanol and drying it in vacuo, thereby obtaining modified nano-silica particles.

(27) The pigment dispersion of this example was prepared by mixing a solute with solvent and inducing a crosslinking reaction therein. The average particle size of the solid particles in the pigment dispersion is 100 nm, and the solute comprises, based on 100% by mass of the pigment dispersion, 2% of the modified nano-silica, 6% of a dispersant, 2% of a binder resin, 10% of a pigment, 0.3% of a photoinitiator, 0.1% of quantum dots (CdTe, particle size: 10 nm), and the rest 79.6% of solvent.

(28) The process for preparing the pigment dispersion comprises the steps of: weighing indanthrene blue RS as a pigment, TR-7010 (a polyurethane) as a dispersant, propylene glycol monomethyl ether acetate as a solvent, and carboxymethyl cellulose as a binder resin, according to the aforesaid mass percentages, and mixing them in a disperser at a speed of 500 rpm for 1 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, and then removing the zirconium oxide beads after completion of milling, thereby obtaining a pigment-containing dispersion liquid; and adding the modified nano-silica of this example and the initiator benzil into the pigment-containing dispersion liquid under stirring, and inducing a crosslinking reaction, after stirring for 1 h, under the irradiation of a UV lamp (GE-B8565) for 40 s, thereby obtaining a pigment dispersion.

(29) The photosensitive resin composition of this example comprises (mass %): 30% of the pigment dispersion as prepared above, 2% of an alkali-soluble resin, 0.3% of a photoinitiator, 5% of a polymerizable monomer, and the rest of solvent.

(30) The process for preparing the photosensitive resin composition comprises the steps of: weighing the pigment dispersion prepared in this example, methacrylic acid/benzyl methacrylate copolymer as an alkali-soluble acrylic copolymer resin (acid value: 50), ethyl methacrylate as a polymerizable monomer, and propylene glycol monomethyl ether acetate as a solvent, according to the aforesaid mass percentages, and mixing them in a ball mill at a speed of 500 rpm for 3 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, then removing the zirconium oxide beads after completion of milling, and then adding the photoinitiator benzil.

(31) The resultant photosensitive resin composition was coated onto a transparent glass substrate provided with a black matrix. After a photoetching process including exposure for 20 s, development and so on, a color layer (i.e., a photoresist layer) of a color filter was obtained. The appearance of the photoresist layer was inspected, and the results are shown in Table 1.

(32) A display panel comprising the color filter was prepared, and further was packaged in a display device. The brightness of the display device was tested at the same power as the Comparative Example, and the results are shown in Table 1.

Example 3

(33) This example provides modified nano-silica particles and a method of preparing the same, as well as a pigment dispersion and a photosensitive resin composition comprising the same.

(34) The modified nano-silica particles provided in this example have unsaturated double bonds grafted on the surface thereof, and have an average particle size of 20 nm.

(35) The method for preparation of the aforesaid modified nano-silica particles comprises the following steps: 1) the step of reacting to produce a nano-silica precursor: dissolving quantum dots (CdTe, particle size: 1 nm) in anhydrous ethanol to form a solution of the quantum dots; and

(36) weighing 30 parts by mass of anhydrous ethanol, 10 parts by mass of deionized water, 8 parts by mass of 25% (v/v) ammonia, 5 parts by mass of vinyl triethoxysilane, and predetermined amount of the quantum dots solution (based on the mass of the modified nano-silica finally obtained, the amount of the quantum dots being 23.3%), and mixing them uniformly in a four-necked flask, then raising the temperature of the resultant mixture to 50 C., then slowly adding dropwise into the flask 25 parts by mass of tetraethyl orthosilicate over 2.5 h, and continuing the reaction for 6 h after completion of the addition, thereby obtaining the nano-silica precursor; and 2) the step of aging the nano-silica precursor: transferring the nano-silica precursor obtained in Step 1) to a thermostatic reactor and aging for 12 h at 120 C., and then filtering the resultant precipitate, washing the cake three times with ethanol and drying it in vacuo, thereby obtaining modified nano-silica particles.

(37) The pigment dispersion of this example was prepared by mixing a solute with solvent and inducing a crosslinking reaction therein. The average particle size of the solid particles in the pigment dispersion is 80 nm, and the solute comprises, based on 100% by mass of the pigment dispersion, 3% of the modified nano-silica, 4% of a dispersant, 3% of a binder resin, 14% of a pigment, 0.4% of a photoinitiator, 0.7% of quantum dots (CdTe, particle size: 1 nm), and the rest 74.9% of solvent.

(38) The process for preparing the pigment dispersion comprises the steps of: weighing benzimidazolone yellow H4G PY151 as a pigment, BYK-130 (polyaminoamide, Disperbyk-130) as a dispersant, propylene glycol monomethyl ether acetate as a solvent, and methacrylic acid/methyl methacrylate resin as a binder resin, according to the aforesaid mass percentages, and mixing them in a disperser at a speed of 500 rpm for 1 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, and then removing the zirconium oxide beads after completion of milling, thereby obtaining a pigment-containing dispersion liquid; and adding the modified nano-silica of this example and the initiator dibenzoyl phenyl phosphine oxide into the pigment-containing dispersion liquid under stirring, and inducing a crosslinking reaction, after stirring for 2 h, under the irradiation of a UV lamp (GE-B8565) for 60 s, thereby obtaining a pigment dispersion.

(39) The photosensitive resin composition of this example comprises (mass %): 35% of the pigment dispersion as prepared above, 3% of an alkali-soluble resin, 0.4% of a photoinitiator, 3% of a polymerizable monomer, and the rest of solvent.

(40) The process for preparing the photosensitive resin composition comprises the steps of: weighing the pigment dispersion prepared in this example, methacrylic acid/methyl methacrylate/styrene copolymer as an alkali-soluble acrylic copolymer resin (acid value: 60), bisphenol A bis(acryloxyethyl) ether as a polymerizable monomer, and propylene glycol monomethyl ether acetate as a solvent, according to the aforesaid mass percentages, and mixing them in a ball mill at a speed of 500 rpm for 3 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, then removing the zirconium oxide beads after completion of milling, and then adding the photoinitiator dibenzoyl phenyl phosphine oxide.

(41) The resultant photosensitive resin composition was coated onto a transparent glass substrate provided with a black matrix. After a photoetching process including exposure for 20 s, development and so on, a color layer (i.e., a photoresist layer) of a color filter was obtained. The appearance of the photoresist layer was inspected, and the results are shown in Table 1.

(42) A display panel comprising the color filter was prepared, and further was packaged in a display device. The brightness of the display device was tested at the same power as the Comparative Example, and the results are shown in Table 1.

Example 4

(43) This example provides modified nano-silica particles and a method of preparing the same, as well as a pigment dispersion and a photosensitive resin composition comprising the same.

(44) The modified nano-silica particles provided in this example have unsaturated double bonds grafted on the surface thereof, and have an average particle size of 20 nm.

(45) The method for preparation of the aforesaid modified nano-silica particles comprises the following steps: 1) the step of reacting to produce a nano-silica precursor: dissolving quantum dots (CdTe, particle size: 2 nm) in anhydrous ethanol to form a solution of the quantum dots; and

(46) weighing 35 parts by mass of anhydrous ethanol, 8 parts by mass of deionized water, 4 parts by mass of 25% (v/v) ammonia, 7 parts by mass of vinyl triacetoxysilane, and predetermined amount of the quantum dots solution (based on the mass of the modified nano-silica finally obtained, the amount of the quantum dots being 25%), and mixing them uniformly in a four-necked flask, then raising the temperature of the resultant mixture to 70 C., then slowly adding dropwise into the flask 23 parts by mass of tetraethyl orthosilicate over 2.7 h, and continuing the reaction for 12 h after completion of the addition, thereby obtaining the nano-silica precursor; and 2) the step of aging the nano-silica precursor: transferring the nano-silica precursor obtained in Step 1) to a thermostatic reactor and aging for 20 h at 140 C., and then filtering the resultant precipitate, washing the cake three times with ethanol and drying it in vacuo, thereby obtaining modified nano-silica particles.

(47) The pigment dispersion of this example was prepared by mixing a solute with solvent and inducing a crosslinking reaction therein. The average particle size of the solid particles in the pigment dispersion is 40 nm, and the solute comprises, based on 100% by mass of the pigment dispersion, 4% of the modified nano-silica, 5% of a dispersant, 4% of a binder resin, 16% of a pigment, 0.1% of a photoinitiator, 1% of quantum dots (CdTe, particle size: 2 nm), and the rest 69.8% of solvent.

(48) The process for preparing the pigment dispersion comprises the steps of: weighing indanthrene blue RS as a pigment, BYK-131 as a dispersant, propylene glycol monomethyl ether acetate as a solvent, and isobutylene-maleic acid resin as a binder resin, according to the aforesaid mass percentages, and mixing them in a disperser at a speed of 500 rpm for 1 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, and then removing the zirconium oxide beads after completion of milling, thereby obtaining a pigment-containing dispersion liquid; and adding the modified nano-silica of this example and the initiator benzoin dimethyl ether into the pigment-containing dispersion liquid under stirring, and inducing a crosslinking reaction, after stirring for 3 h, under the irradiation of a UV lamp (GE-B8565) for 50 s, thereby obtaining a pigment dispersion.

(49) The photosensitive resin composition of this example comprises (mass %): 38% of the pigment dispersion as prepared above, 6% of an alkali-soluble resin, 0.8% of a photoinitiator, 4% of a polymerizable monomer, and the rest of solvent.

(50) The process for preparing the photosensitive resin composition comprises the steps of: weighing the pigment dispersion prepared in this example, (meth)acrylic acid/2-hydroxyethyl methacrylate/benzyl methacrylate/methyl methacrylate copolymer as an alkali-soluble acrylic copolymer resin (acid value: 120), pentaerythritol tetra(meth)acrylate as a polymerizable monomer, and propylene glycol monomethyl ether acetate as a solvent, according to the aforesaid mass percentages, and mixing them in a ball mill at a speed of 500 rpm for 3 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, then removing the zirconium oxide beads after completion of milling, and then adding the photoinitiator benzoin dimethyl ether.

(51) The resultant photosensitive resin composition was coated onto a transparent glass substrate provided with a black matrix. After a photoetching process including exposure for 20 s, development and so on, a color layer (i.e., a photoresist layer) of a color filter was obtained. The appearance of the photoresist layer was inspected, and the results are shown in Table 1.

(52) A display panel comprising the color filter was prepared, and further was packaged in a display device. The brightness of the display device was tested at the same power as the Comparative Example, and the results are shown in Table 1.

Example 5

(53) This example provides modified nano-silica particles and a method of preparing the same, as well as a pigment dispersion and a photosensitive resin composition comprising the same.

(54) The modified nano-silica particles provided in this example have unsaturated double bonds grafted on the surface thereof, and have an average particle size of 50 nm.

(55) The method for preparation of the aforesaid modified nano-silica particles comprises the following steps: 1) the step of reacting to produce a nano-silica precursor: dissolving quantum dots (CdTe, particle size: 4.5 nm) in anhydrous ethanol to form a solution of the quantum dots; and

(56) weighing 25 parts by mass of anhydrous ethanol, 6 parts by mass of deionized water, 5 parts by mass of 25% (v/v) ammonia, 9 parts by mass of vinyl triisopropoxysilane, and predetermined amount of the quantum dots solution (based on the mass of the modified nano-silica finally obtained, the amount of the quantum dots being 10%), and mixing them uniformly in a four-necked flask, then raising the temperature of the resultant mixture to 50 C., then slowly adding dropwise into the flask 18 parts by mass of tetraethyl orthosilicate over 3 h, and continuing the reaction for 8 h after completion of the addition, thereby obtaining the nano-silica precursor; and 2) the step of aging the nano-silica precursor: transferring the nano-silica precursor obtained in Step 1) to a thermostatic reactor and aging for 24 h at 130 C., and then filtering the resultant precipitate, washing the cake three times with ethanol and drying it in vacuo, thereby obtaining modified nano-silica particles.

(57) The pigment dispersion of this example was prepared by mixing a solute with solvent and inducing a crosslinking reaction therein. The average particle size of the solid particles in the pigment dispersion is 70 nm, and the solute comprises, based on 100% by mass of the pigment dispersion, 5% of the modified nano-silica, 4.5% of a dispersant, 5% of a binder resin, 18% of a pigment, 0.5% of a photoinitiator, 0.5% of quantum dots (CdTe, particle size: 4.5 nm), and the rest 66.5% of solvent.

(58) The process for preparing the pigment dispersion comprises the steps of: weighing carbazole dioxazine Violet 19 as a pigment, Disperbyk-161 as a dispersant, propylene glycol monomethyl ether acetate as a solvent, and polyvinyl pyrrolidone as a binder resin, according to the aforesaid mass percentages, and mixing them in a disperser at a speed of 500 rpm for 1 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, and then removing the zirconium oxide beads after completion of milling, thereby obtaining a pigment-containing dispersion liquid; and adding the modified nano-silica of this example and the initiator p-benzoyl phenoxy diphenyl iodonium hexafluorophosphate into the pigment-containing dispersion liquid under stirring, and inducing a crosslinking reaction, after stirring for 2.5 h, under the irradiation of a UV lamp (GE-B8565) for 45 s, thereby obtaining a pigment dispersion.

(59) The photosensitive resin composition of this example comprises (mass %): 40% of the pigment dispersion as prepared above, 5% of an alkali-soluble resin, 0.5% of a photoinitiator, 2.5% of a polymerizable monomer, and the rest of solvent.

(60) The process for preparing the photosensitive resin composition comprises the steps of: weighing the pigment dispersion prepared in this example, (meth)acrylic acid/benzyl methacrylate/N-phenyl maleimide copolymer as an alkali-soluble acrylic copolymer resin (acid value: 100), styrene as a polymerizable monomer, and propylene glycol monomethyl ether acetate as a solvent, according to the aforesaid mass percentages, and mixing them in a ball mill at a speed of 500 rpm for 3 h, and then dispersing the obtained mixture in a high speed stirring mill for 5 h after adding appropriate amount of zirconium oxide beads having an average particle size of 0.3 to 1.0 mm, then removing the zirconium oxide beads after completion of milling, and then adding the photoinitiator p-benzoyl phenoxy diphenyl iodonium hexafluorophosphate.

(61) The resultant photosensitive resin composition was coated onto a transparent glass substrate provided with a black matrix. After a photoetching process including exposure for 20 s, development and so on, a color layer (i.e., a photoresist layer) of a color filter was obtained. The appearance of the photoresist layer was inspected, and the results are shown in Table 1.

(62) A display panel comprising the color filter was prepared, and further was packaged in a display device. The brightness of the display device was tested at the same power as the Comparative Example, and the results are shown in Table 1.

(63) TABLE-US-00002 TABLE 1 Comparison of appearance of the photoresist layers and brightness of the display devices Brightness (the result of Appearance of the Comparative Example Example No. photoresist layer serving as a reference value) Comparative With shrinkage and collapse Reference value Example Example 1 No shrinkage or collapse Reference value Example 2 No shrinkage or collapse Improved by 9% Example 3 No shrinkage or collapse Improved by 8% Example 4 No shrinkage or collapse Improved by 13% Example 5 No shrinkage or collapse Improved by 12%

(64) As shown in Table 1, the photoresist layers comprising the modified nano-silica prepared according to the present invention exhibited no shrinkage or collapse, whereas shrinkage and collapse occurred in the photoresist layer of Comparative Example. Such results demonstrate that the modified nano-silica according to the present invention can be polymerized and crosslinked with polymerizable monomers to form an interpenetrating composite network structure, so as to enhance the support effect. The display devices of Examples 2-5 comprising quantum dots have an improved brightness, compared to the display devices of Comparative Example and Example 1 without quantum dots. Such results demonstrate that the addition of quantum dots has significant effect on improvement of the brightness of display devices and on energy saving.

(65) Since the modified nano-silica particles according to the present invention have unsaturated double bonds on the surface thereof, they can crosslink with other polymeric materials. Meanwhile, since the modified nano-silica particles having a particle size according to the present invention are much smaller than the size of the organic pigment capable of being dispersed, they will be separated by the steric hindrance effect of the binder resin covered on the surface of the pigment after they are added to the pigment paste and evenly dispersed. Furthermore, the functional groups of the modified nano-silica particles per se can prevent them from agglomerating and thus are suitable for forming nodes of a crosslinked network that connect the chain segments of polymeric materials to form a network structure.

(66) According to the present invention, modified nano-silica particles are added in a pigment dispersion to serve as crosslinking nodes, and the binder resin containing unsaturated double bonds in the dispersion is initiated to undergo crosslinking polymerization to form a network polymeric resin system in the dispersion. As such, the effect of encapsulation and stabilization of the pigment particles is enhanced and the occurrence of particle agglomeration and precipitation is effectively decreased.

(67) During the exposure stage after a photosensitive resin composition is prepared by adding an alkali-soluble resin, a polymerizable monomer, a photoinitiator and other additives to a pigment dispersion, a network structure is formed by the polymerization and crosslinking of the polymerizable monomer, which combines with the network crosslinked structure comprising the nano-silica particles in the pigment dispersion to form an interpenetrating composite network structure. The two kinds of network in the composite structure interpenetrate and cooperate with each other such that they can support each other in the post-baking stage, thereby reducing the thermal expansion of the resultant film as well as the occurrence of shrinkage and collapse phenomena in the surface of the film, and effectively enhancing the heat-resistance, chemical-resistance, mechanical properties and abrasion-resistance of the film, while maintaining the transparency and gloss of the film without any adverse effect on the optical properties of the photosensitive resin.

(68) It should be understood that the embodiments described above are provided for the purpose of illustrating the principle of the invention, while the invention is not limited thereto. It will be apparent to a person skilled in the art that various changes and modifications can be made to the invention without departing from the spirit of the invention, and such changes and modifications are within the scope of the present invention.