Modified titanium dioxide and preparation method and application thereof

Abstract

The invention relates to modified titanium dioxide as well as a preparation method and application thereof. The modified titanium dioxide is prepared from the following raw materials: titanium dioxide, a silane coupling agent, long-carbon-chain organic acid and polyol. According to the modified titanium dioxide provided by the invention, the titanium dioxide is modified by the silane coupling agent, the long-carbon-chain organic acid and the polyhydric alcohol, so that the dispersion speed and the dispersion stability of the modified titanium dioxide in a resin composition can be remarkably improved, and the resin composition can have excellent leveling property.

Description

Technical Field

[0001] This invention belongs to the field of titanium dioxide modification technology, specifically relating to a modified titanium dioxide, its preparation method, and its application. Background Technology

[0002] Titanium dioxide (TiO2), as an important white pigment and functional filler, is widely used in coatings, plastics, inks, and composite materials. However, untreated titanium dioxide, due to its highly polar surface, is prone to absorbing water and agglomerating during production, storage, and transportation. This agglomeration in organic polymers limits its applications, especially in high-performance resin systems such as epoxy resins and cyanate ester resins, where the dispersion problem of titanium dioxide is more prominent, directly affecting the mechanical, optical, and processing properties of the composite materials.

[0003] White mini-LED backlight panels, or simply "white boards," are the encapsulation substrate for mini-LED self-emissive LED chips in next-generation LCD display technology. They require high standards for whiteness, reflectivity, resistance to yellowing, and thermal conductivity. To improve whiteness, the industry practice is to add titanium dioxide to the resin formulation, with addition levels reaching 40% or higher. However, excessive addition can lead to problems such as adhesive thickening and filler sedimentation. To achieve excellent processing performance, the titanium dioxide must undergo organic coating treatment.

[0004] In the prior art, silane coupling agents (such as KH550, KH560, etc.) are widely used for surface treatment of titanium dioxide to improve its dispersibility in resins. However, treatment with a single silane coupling agent often fails to simultaneously meet the multiple requirements of dispersion speed, dispersion stability, and leveling. CN105567054A discloses a high heat-resistant epoxy resin-based powder coating, in which titanium dioxide is treated with silane coupling agents (KH550, KH551, KH560 or KH580), but this method has limited improvement on the dispersion speed and stability of titanium dioxide in resins. CN117645802A discloses a method for preparing surface-modified titanium dioxide, which uses hydroxyl telechelic natural rubber to modify the surface of titanium dioxide. Although this improves the dispersibility of titanium dioxide in the rubber matrix, it is not suitable for high-performance resin systems such as epoxy resins and cyanate ester resins. Therefore, developing a modified titanium dioxide that can significantly improve the dispersion speed and dispersion stability of titanium dioxide in high-performance resin systems, while improving the leveling properties of the resin system, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a modified titanium dioxide, its preparation method and application. By designing the raw materials, the modified titanium dioxide can have good dispersion stability and fast dispersion speed in the resin composition, while also improving the leveling properties of the resin composition.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include titanium dioxide, silane coupling agent, long-chain organic acid and polyol.

[0008] The modified titanium dioxide provided by this invention reduces the interaction force between titanium dioxide particles by introducing long-chain organic acids, and the polyol enables titanium dioxide to have good compatibility with thermosetting resins. The synergistic effect of the two can improve the leveling performance of the resin composition. Through the combined action of silane coupling agents, long-chain organic acids and polyols, the dispersion speed and dispersion stability of titanium dioxide in the resin composition can be improved.

[0009] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0010] As a preferred technical solution, the titanium dioxide includes rutile titanium dioxide produced by the sulfuric acid process.

[0011] Preferably, the titanium dioxide is titanium dioxide after the coating has been removed.

[0012] Existing titanium dioxide is generally coated with inorganic materials, which forms a single or multiple inorganic film on the surface of the titanium dioxide particles. In order to better modify titanium dioxide, the coating on the surface of titanium dioxide needs to be removed.

[0013] Preferably, the titanium dioxide has a D 50 The particle size is 0.5-2μm, for example, it can be 0.52μm, 0.54μm, 0.56μm, 0.58μm, 0.6μm, 0.8μm, 1μm, 1.2μm, 1.4μm, 1.6μm, 1.8μm, etc.

[0014] In this invention, the titanium dioxide has a D 50 The particle size was obtained according to GB / T 41949-2022.

[0015] Preferably, the silane coupling agent comprises any one or a combination of at least two of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane.

[0016] Preferably, the long-chain organic acid includes organic acids containing C10-C18 straight-chain alkyl or C10-C18 straight-chain alkenyl groups, and more preferably oleic acid and / or stearic acid.

[0017] Preferably, the polyol includes triols and / or tetraols, and more preferably trimethylolpropane or pentaerythritol.

[0018] Preferably, based on the mass of the titanium dioxide as 100%, the mass of the silane coupling agent is 1-3%, for example, it can be 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, etc.

[0019] Preferably, based on the mass of the titanium dioxide as 100%, the mass of the long-chain organic acid is 1-5%, for example, it can be 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, etc.

[0020] Preferably, based on the mass of the titanium dioxide as 100%, the mass of the polyol is 0.5-2%, for example, it can be 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, etc.

[0021] Preferably, the mass ratio of the long-chain organic acid to the polyol is (1-5):1, for example, it can be 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1, etc., and more preferably (2-4):1.

[0022] In a second aspect, the present invention provides a method for preparing modified titanium dioxide as described in the first aspect, the method comprising:

[0023] Titanium dioxide was modified using silane coupling agents, long-chain organic acids, and polyols to obtain the modified titanium dioxide.

[0024] Preferably, the preparation method specifically includes the following steps:

[0025] (1) Titanium dioxide was modified with silane coupling agent to obtain silane coupling agent modified titanium dioxide;

[0026] (2) The silane coupling agent modified titanium dioxide, long-chain organic acid and polyol are reacted to obtain the modified titanium dioxide.

[0027] The modified titanium dioxide preparation method provided by this invention is simple to operate and has mild process conditions. First, titanium dioxide is initially modified with a silane coupling agent, and then modified with long-chain organic acids and polyols, thereby forming a stable modification layer on the surface of titanium dioxide. This can significantly improve the dispersion speed and dispersion stability of titanium dioxide in resin compositions and improve the leveling properties of resin compositions.

[0028] Preferably, the modification in step (1) is carried out by the following method, the method comprising:

[0029] A silane coupling agent, water, and ethanol are mixed to obtain a treatment solution; the treatment solution is sprayed onto titanium dioxide, and after a first drying process, it is pulverized to obtain the silane coupling agent modified titanium dioxide.

[0030] Preferably, in the treatment solution, the mass of water is 5-20% based on 100% of the silane coupling agent, for example, it can be 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, etc.

[0031] Preferably, in the treatment solution, based on the mass of the silane coupling agent being 100%, the mass of the ethanol is 80-95%, for example, it can be 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, etc.

[0032] Preferably, the first drying is carried out at 18-35℃ (e.g., 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, 32℃, 34℃, etc.) for 36-60 hours (e.g., 38 h, 40 h, 42 h, 44 h, 46 h, 48 h, 50 h, 52 h, 54 h, 56 h, 58 h, etc.), and then at 100-110℃ (101℃, 102℃, 103℃, 104℃, 105℃, 106℃, 107℃, 108℃, 109℃, etc.) for 2-4 hours (e.g., 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, etc.).

[0033] Preferably, the reaction temperature is 30-50℃, for example, 32℃, 34℃, 36℃, 38℃, 40℃, 42℃, 44℃, 46℃, 48℃, etc.

[0034] Preferably, the reaction time is 2-4 hours, for example, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, etc.

[0035] Preferably, the reaction is carried out in the presence of an organic solvent.

[0036] Preferably, the organic solvent includes ethanol.

[0037] Preferably, the mass ratio of the organic solvent to titanium dioxide is (2-5):1, for example, it can be 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1, 4.2:1, 4.4:1, 4.6:1, 4.8:1, etc.

[0038] The modified titanium dioxide preparation method provided by this invention combines dry mechanical processing and wet chemical modification, which retains the advantages of the simple and efficient dry process, and achieves a more stable surface modification effect on titanium dioxide through wet chemical modification.

[0039] Preferably, the reaction further includes a second drying step after completion.

[0040] Preferably, the temperature of the second drying is 50-80℃, for example, it can be 52℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃, 70℃, 72℃, 75℃, 78℃, etc.

[0041] Preferably, the second drying time is 4-8 hours, for example, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, etc.

[0042] Preferably, the titanium dioxide is pretreated before the modification in step (1), and the pretreatment includes calcination, alkaline cleaning, third drying and grinding in sequence.

[0043] The present invention removes the organic modification on the surface of titanium dioxide by calcination and removes the inert coating on the surface of titanium dioxide by alkaline washing.

[0044] Preferably, the roasting temperature is 400-500℃, for example, it can be 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃, etc.

[0045] Preferably, the roasting time is 1-3 hours, for example, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, etc.

[0046] Preferably, the alkaline solution comprises a sodium hydroxide solution.

[0047] Preferably, the concentration of the sodium hydroxide solution is 1-3 mol / L, for example, it can be 1.2 mol / L, 1.4 mol / L, 1.6 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L, 2.4 mol / L, 2.6 mol / L, 2.8 mol / L, etc.

[0048] Preferably, the alkaline solution is used for cleaning 2-4 times, with each cleaning session lasting 20-40 minutes.

[0049] Preferably, the temperature of the third drying is 110-150℃, for example, it can be 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, etc.

[0050] Preferably, the third drying time is 2-4 hours, for example, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, etc.

[0051] Thirdly, the present invention provides a resin composition comprising modified titanium dioxide, thermosetting resin and curing agent as described in the first aspect.

[0052] Preferably, the thermosetting resin includes epoxy resin or cyanate ester resin.

[0053] Preferably, the epoxy resin comprises 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate and / or bisphenol A type epoxy resin.

[0054] Preferably, the bisphenol A type epoxy resin includes E-51 type epoxy resin and / or E-12 type epoxy resin.

[0055] Preferably, the modified titanium dioxide is 5-50% by mass, based on 100% of the thermosetting resin, for example, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, etc.

[0056] Preferably, the curing agent includes methyltetrahydrophthalic anhydride and / or phthalic anhydride.

[0057] Preferably, the curing agent accounts for 30-40% of the mass of the thermosetting resin (100%), for example, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, etc.

[0058] In this invention, the resin composition is prepared by the following method, the method comprising:

[0059] After mixing thermosetting resin and modified titanium dioxide, a curing agent is added to obtain the resin composition.

[0060] Preferably, the stirring speed is 2000-4000 r / min, for example, it can be 2200 r / min, 2400 r / min, 2600 r / min, 2800 r / min, 3000 r / min, 3200 r / min, 3400 r / min, 3600 r / min, 3800 r / min, etc.

[0061] Preferably, the mixing time is 35-60 minutes, for example, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, etc.

[0062] Fourthly, the present invention provides a white LED backlight panel, wherein the raw materials for preparing the white LED backlight panel include the resin composition described in the third aspect.

[0063] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] The modified titanium dioxide provided by this invention is modified by silane coupling agent, long-chain organic acid and polyol, which can significantly improve its dispersion speed and dispersion stability in resin composition, and also make the resin composition have excellent leveling properties; wherein the dispersion time of the modified titanium dioxide is 35-60 min, and after mixing with thermosetting resin, stratification or precipitation occurs 6-12 days later, and after the resin composition is scraped, the coating roughness is 0.60-0.82 μm. Detailed Implementation

[0066] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0067] The sources of some components in the following examples and comparative examples are as follows:

[0068] (1) Sulfuric acid process rutile titanium dioxide: Wuhan Fangyuan Titanium Dioxide Co., Ltd., D 50Particle sizes of 0.52 μm, 1.15 μm, and 1.87 μm, with TiO2 ≥ 98%;

[0069] (2) Long-chain organic acids:

[0070] Oleic acid, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0071] Stearic acid, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0072] (3) Silane coupling agent:

[0073] γ-aminopropyltriethoxysilane, Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0074] γ-glycidyl etheroxypropyltrimethoxysilane, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0075] γ-Methacryloxypropyltrimethoxysilane, Shanghai McLean Biochemical Technology Co., Ltd.

[0076] Example 1

[0077] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide, 2g of γ-aminopropyltriethoxysilane, 3g of oleic acid and 1g of trimethylolpropane;

[0078] The preparation method of the modified titanium dioxide includes the following steps:

[0079] (1) The sulfuric acid process rutile titanium dioxide (D 50 The titanium dioxide (particle size 1.15 μm) was placed in a muffle furnace and heated to 500 °C at a heating rate of 5 °C / min, and calcined at this temperature for 2 h. It was then allowed to cool naturally to room temperature. The calcined titanium dioxide was placed in a 500 mL beaker, and 300 mL of 2 mol / L NaOH solution was added. The mixture was then treated with an ultrasonic cleaner and vibrated for 30 minutes. This process was repeated 3 times. The mixture was washed with deionized water until neutral, filtered, and then dried in a vacuum drying oven at 110 °C for 2 h. Finally, it was ground in a mortar and pestle to obtain the decoated sulfuric acid rutile titanium dioxide.

[0080] Add 1.7g of anhydrous ethanol to a 50mL beaker, turn on magnetic stirring (500rpm), add 2g of γ-aminopropyltriethoxysilane and 0.3g of deionized water in sequence, stir for 15 minutes to obtain a treatment solution; spray the treatment solution evenly onto 100g of the decoated sulfuric acid rutile titanium dioxide using a spray device, then dry it naturally for 48h, crush it with a mortar and pestle, and bake it at 100℃ for 3h; then place it in a mechanical pulverizer and pulverize it for 4 minutes to obtain silane coupling agent modified titanium dioxide;

[0081] (2) The silane coupling agent modified titanium dioxide was placed in a 500mL three-necked flask, and 400mL of anhydrous ethanol, 3g of oleic acid and 1g of trimethylolpropane were added. The mixture was ultrasonically treated in a 50℃ water bath for 2 hours. The suspension was transferred to a centrifuge tube and centrifuged at 4000rpm for 10 minutes. The supernatant was discarded and the mixture was washed three times each with acetone and n-hexane. After each washing, the mixture was centrifuged. Finally, the precipitate was placed in a vacuum drying oven and dried at 50℃ for 4 hours to obtain the modified titanium dioxide.

[0082] Example 2

[0083] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide, 2g of γ-glycidyl etheroxypropyltrimethoxysilane, 4g of stearic acid and 1.5g of pentaerythritol;

[0084] The preparation method of the modified titanium dioxide includes the following steps:

[0085] (1) Perform the same procedure as in Example 1 on sulfuric acid process rutile titanium dioxide (D 50 Pretreatment was performed on titanium dioxide with a particle size of 0.52 μm to obtain decoated rutile titanium dioxide produced by the sulfuric acid process. 1.7 g of anhydrous ethanol was added to a 50 mL beaker, and magnetic stirring (500 rpm) was started. 2 g of γ-glycidyl etheroxypropyltrimethoxysilane and 0.3 g of deionized water were added sequentially, and the mixture was stirred for 15 minutes to obtain a treatment solution. The treatment solution was evenly sprayed onto 100 g of the decoated rutile titanium dioxide produced by the sulfuric acid process using a spray device, and then naturally dried for 48 h. The mixture was then crushed in a mortar and pestle and baked at 100 °C for 3 h. Finally, it was pulverized in a mechanical grinder for 4 minutes to obtain silane coupling agent modified titanium dioxide.

[0086] (2) The silane coupling agent modified titanium dioxide was placed in a 500mL three-necked flask, and 400mL of anhydrous ethanol, 4g of stearic acid and 1.5g of pentaerythritol were added. The mixture was ultrasonically treated in a 50℃ water bath for 3 hours. The suspension was transferred to a centrifuge tube and centrifuged at 4000rpm for 10 minutes. The supernatant was discarded and the mixture was washed three times each with acetone and n-hexane. After each washing, the mixture was centrifuged. Finally, the precipitate was placed in a vacuum drying oven and dried at 50℃ for 4 hours to obtain the modified titanium dioxide.

[0087] Example 3

[0088] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide, 1g of γ-aminopropyltriethoxysilane, 2g of γ-methacryloyloxypropyltrimethoxysilane, 4g of stearic acid and 1.5g of pentaerythritol.

[0089] The preparation method of the modified titanium dioxide includes the following steps:

[0090] (1) Perform the same procedure as in Example 1 on sulfuric acid process rutile titanium dioxide (D 50 Pretreatment was performed on particles with a diameter of 1.87 μm to obtain decoated rutile titanium dioxide produced by the sulfuric acid process.

[0091] Add 2.7g of anhydrous ethanol to a 50mL beaker, turn on magnetic stirring (500rpm), and add 1g of γ-aminopropyltriethoxysilane, 2g of γ-methacryloyloxypropyltrimethoxysilane and 0.3g of deionized water in sequence. Stir for 15 minutes to obtain a treatment solution. Spray the treatment solution evenly onto 100g of the decoated sulfuric acid rutile titanium dioxide using a spray device, then dry it naturally for 48h, crush it with a mortar and pestle, and bake it at 100℃ for 3h. Then, place it in a mechanical pulverizer and pulverize it for 4 minutes to obtain silane coupling agent modified titanium dioxide.

[0092] (2) The silane coupling agent modified titanium dioxide was placed in a 500mL three-necked flask, and 400mL of anhydrous ethanol, 4g of stearic acid and 1.5g of pentaerythritol were added. The mixture was ultrasonically treated in a 50℃ water bath for 4 hours. The suspension was transferred to a centrifuge tube and centrifuged at 4000rpm for 10 minutes. The supernatant was discarded and the mixture was washed three times each with acetone and n-hexane. After each washing, the mixture was centrifuged. Finally, the precipitate was placed in a vacuum drying oven and dried at 50℃ for 4 hours to obtain the modified titanium dioxide.

[0093] Example 4

[0094] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide, 2g of γ-aminopropyltriethoxysilane, 2.7g of oleic acid and 1.3g of trimethylolpropane;

[0095] The only difference between the preparation method of the modified titanium dioxide and Example 1 is that the amount of oleic acid used in step (2) is 2.7g and the amount of trimethylolpropane used is 1.3g. The other raw materials, process parameters and steps are the same as in Example 1.

[0096] Example 5

[0097] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide, 2g of γ-aminopropyltriethoxysilane, 3.3g of oleic acid and 0.7g of trimethylolpropane;

[0098] The only difference between the preparation method of the modified titanium dioxide and Example 1 is that the amount of oleic acid used in step (2) is 3.3g and the amount of trimethylolpropane used is 0.7g. The other raw materials, process parameters and steps are the same as in Example 1.

[0099] Example 6

[0100] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide, 2g of γ-aminopropyltriethoxysilane, 2g of oleic acid and 2g of trimethylolpropane.

[0101] The only difference between the preparation method of the modified titanium dioxide and Example 1 is that the amount of oleic acid used in step (2) is 2g and the amount of trimethylolpropane used is 2g. The other raw materials, process parameters and steps are the same as in Example 1.

[0102] Example 7

[0103] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide, 2g of γ-aminopropyltriethoxysilane, 3g of oleic acid and 1g of trimethylolpropane;

[0104] The preparation method of the modified titanium dioxide includes the following steps:

[0105] The decoated sulfuric acid rutile titanium dioxide was obtained by the same procedure as in Example 1. 100g of the decoated sulfuric acid rutile titanium dioxide, 2g of γ-aminopropyltriethoxysilane, 3g of oleic acid, 1g of trimethylolpropane, and 400mL of ethanol were mixed and sonicated at 50°C for 4 hours. The suspension was transferred to a centrifuge tube and centrifuged at 4000rpm for 10 minutes. The supernatant was discarded, and the mixture was washed three times each with acetone and n-hexane, centrifuged after each wash. Finally, the precipitate was placed in a vacuum drying oven and dried at 50°C for 4 hours to obtain the modified titanium dioxide.

[0106] Comparative Example 1

[0107] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide and 6g of γ-aminopropyltriethoxysilane.

[0108] The method for preparing the modified titanium dioxide includes:

[0109] Following the same procedure as in Example 1, decoated sulfuric acid rutile titanium dioxide was obtained. 5.1 g of anhydrous ethanol was added to a 50 mL beaker, and magnetic stirring (500 rpm) was started. 6 g of γ-aminopropyltriethoxysilane and 0.9 g of deionized water were added, and the mixture was stirred for 15 minutes to obtain a treatment solution. The treatment solution was evenly sprayed onto 100 g of the decoated sulfuric acid rutile titanium dioxide using a spray device, and then naturally dried for 48 hours. The mixture was then crushed in a mortar and pestle and baked at 100°C for 3 hours. Afterward, it was placed in a mechanical pulverizer and pulverized for 4 minutes to obtain the modified titanium dioxide.

[0110] Comparative Example 2

[0111] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated rutile titanium dioxide produced by the sulfuric acid process and 6g of oleic acid;

[0112] The method for preparing the modified titanium dioxide includes:

[0113] Following the same procedure as in Example 1, decoated sulfuric acid rutile titanium dioxide was obtained. The decoated sulfuric acid rutile titanium dioxide was placed in a 500 mL three-necked flask, and 400 mL of anhydrous ethanol and 6 g of oleic acid were added. The mixture was ultrasonically treated in a 50 °C water bath for 2 hours. The suspension was transferred to a centrifuge tube and centrifuged at 4000 rpm for 10 minutes. The supernatant was discarded, and the mixture was washed three times each with acetone and n-hexane, centrifuged after each wash. Finally, the precipitate was placed in a vacuum drying oven and dried at 50 °C for 4 hours to obtain the modified titanium dioxide.

[0114] Comparative Example 3

[0115] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide and 6g of trimethylolpropane;

[0116] The only difference between the preparation method of the modified titanium dioxide and Comparative Example 2 is that oleic acid is replaced by trimethylolpropane by mass, while the other raw materials, process parameters and steps are the same as those in Comparative Example 2.

[0117] Comparative Example 4

[0118] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide, 2g of γ-aminopropyltriethoxysilane, and 4g of oleic acid;

[0119] The only difference between the preparation method of the modified titanium dioxide and Example 1 is that trimethylolpropane is not used in step (2), and the amount of oleic acid is increased to 4g. The other raw materials, process parameters and steps are the same as in Example 1.

[0120] Comparative Example 5

[0121] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide, 2g of γ-aminopropyltriethoxysilane and 4g of trimethylolpropane;

[0122] The only difference between the preparation method of the modified titanium dioxide and Example 1 is that oleic acid is not used in step (2), and the amount of trimethylolpropane is increased to 4g. The other raw materials, process parameters and steps are the same as in Example 1.

[0123] Comparative Example 6

[0124] A modified titanium dioxide, wherein the raw materials for preparing the modified titanium dioxide include 100g of decoated sulfuric acid rutile titanium dioxide, 5g of oleic acid and 1g of trimethylolpropane;

[0125] The method for preparing the modified titanium dioxide includes:

[0126] Following the same procedure as in Example 1, decoated sulfuric acid rutile titanium dioxide was obtained. The decoated sulfuric acid rutile titanium dioxide was placed in a 500 mL three-necked flask, and 400 mL of anhydrous ethanol, 5 g of oleic acid, and 1 g of trimethylolpropane were added. The mixture was ultrasonically treated in a 50°C water bath for 2 hours. The suspension was transferred to a centrifuge tube and centrifuged at 4000 rpm for 10 minutes. The supernatant was discarded, and the mixture was washed three times each with acetone and n-hexane, centrifuged after each wash. Finally, the precipitate was placed in a vacuum drying oven and dried at 50°C for 4 hours to obtain the modified titanium dioxide.

[0127] Application Example 1

[0128] A resin composition comprising 100g of E-51 type epoxy resin (purchased from Baling Petrochemical Epoxy Resin Co., Ltd., CYD-128), 20g of modified titanium dioxide provided in Example 1, and 35g of methyltetrahydrophthalic anhydride curing agent.

[0129] The method for preparing the resin composition includes:

[0130] E-51 type epoxy resin was placed in a 500mL beaker, modified titanium dioxide was added, and the mixture was dispersed at 3000rpm for 60 minutes using a high-speed disperser. During the dispersion process, the temperature was controlled not to exceed 40℃. Methyltetrahydrophthalic anhydride curing agent was added, and the resin composition was obtained after vacuum degassing.

[0131] Application Example 2-7, Comparison with Application Example 1-6

[0132] A resin composition and its preparation method are disclosed, which differ from Application Example 1 only in that the modified titanium dioxide provided in Example 1 is replaced by the modified titanium dioxide provided in Examples 2-7 and Comparative Examples 1-6, while the other raw materials, process parameters and steps are the same as in Application Example 1.

[0133] Comparative Application Example 7

[0134] A resin composition and its preparation method are disclosed, which differ from Application Example 1 only in that the modified titanium dioxide provided in Example 1 is replaced by unmodified sulfuric acid rutile titanium dioxide (uncoated) in equal mass. All other raw materials, process parameters and steps are the same as in Application Example 1.

[0135] Performance testing

[0136] (1) Dispersion time: 2g of modified titanium dioxide was added to 10g of E-51 epoxy resin (purchased from Baling Petrochemical Epoxy Resin Co., Ltd., CYD-128), the disperser was started and the timer was started, and the stirring speed was 3000rpm. Determination of dispersion endpoint: 0.1g of dispersion was taken every 5 minutes and coated onto a glass plate to check the particle agglomeration. The timer was stopped when no visible particles were observed. The dispersion time was measured. The unmodified sulfuric acid rutile titanium dioxide was used as a blank control and its dispersion time was tested using the same method.

[0137] (2) Dispersion stability test: The well dispersed mixture in test (1) is injected into a transparent glass test tube and sealed. It is placed vertically in a 25°C environment and observed periodically. The time when stratification or precipitation occurs is recorded.

[0138] The modified titanium dioxide and unmodified rutile titanium dioxide produced by the sulfuric acid process provided in the examples and comparative examples were tested according to the above method. The test results are shown in Table 1 below:

[0139] Table 1

[0140]

[0141] As can be seen from the test data in Table 1, the modified titanium dioxide provided by the present invention has good dispersion stability and fast dispersion speed in epoxy resin.

[0142] As can be seen from the comparison of Example 1 and Comparative Examples 1-6, using only one or two of the following—silane coupling agents, long-chain organic acids, and polyols—to modify titanium dioxide cannot effectively improve the dispersion speed and dispersion stability of titanium dioxide.

[0143] (3) Coating leveling: The resin composition was coated onto the glass substrate with a 300μm doctor blade and cured at 80℃ for 2 hours and 120℃ for 2 hours. Using a contact profilometer (Talysurf), 5 points were randomly selected on the coating surface to measure the arithmetic mean roughness (Ra). The lower the Ra value, the smoother the surface and the better the leveling.

[0144] The resin compositions provided in the application examples and comparative application examples were tested according to the above method, and the test results are shown in Table 2 below:

[0145] Table 2

[0146]

[0147] As can be seen from the test data in Table 2, the resin composition containing the modified titanium dioxide provided by the present invention has better leveling properties compared to Comparative Application Example 7.

[0148] As can be seen from the comparison between Application Example 1 and Comparative Application Examples 1-6, it is not possible to effectively improve the leveling properties of the resin composition by using only one or two of the following: silane coupling agent, long-chain organic acid and polyol to modify titanium dioxide.

[0149] The applicant declares that this invention illustrates the modified titanium dioxide, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A modified titanium dioxide, characterized in that, The raw materials for preparing the modified titanium dioxide include titanium dioxide, silane coupling agent, long-chain organic acid, and polyol.

2. The modified titanium dioxide according to claim 1, characterized in that, The titanium dioxide includes rutile titanium dioxide produced by the sulfuric acid process. Preferably, the titanium dioxide is titanium dioxide after the coating has been removed; Preferably, the titanium dioxide has a D 50 The particle size is 0.5-2μm; Preferably, the silane coupling agent comprises any one or a combination of at least two of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane; Preferably, the long-chain organic acid includes oleic acid and / or stearic acid; Preferably, the polyol comprises trimethylolpropane and / or pentaerythritol.

3. The modified titanium dioxide according to claim 1 or 2, characterized in that, Based on the mass of the titanium dioxide being 100%, the mass of the silane coupling agent is 1-3%. Preferably, based on the mass of the titanium dioxide as 100%, the mass of the long-chain organic acid is 1-5%; Preferably, based on the mass of the titanium dioxide as 100%, the mass of the polyol is 0.5-2%; Preferably, the mass ratio of the long-chain organic acid to the polyol is (1-5):1, and more preferably (2-4):

1.

4. A method for preparing modified titanium dioxide as described in any one of claims 1-3, characterized in that, The preparation method includes: Titanium dioxide was modified using silane coupling agents, long-chain organic acids, and polyols to obtain the modified titanium dioxide.

5. The preparation method according to claim 4, characterized in that, The preparation method specifically includes the following steps: (1) Titanium dioxide was modified with silane coupling agent to obtain silane coupling agent modified titanium dioxide; (2) The silane coupling agent modified titanium dioxide, long-chain organic acid and polyol are reacted to obtain the modified titanium dioxide; Preferably, the modification in step (1) is carried out by the following method, the method comprising: A silane coupling agent, water, and ethanol are mixed to obtain a treatment solution; the treatment solution is sprayed onto titanium dioxide, and after a first drying process, it is pulverized to obtain the silane coupling agent modified titanium dioxide. Preferably, in the treatment solution, the water comprises 5-20% by mass, based on 100% of the silane coupling agent. Preferably, in the treatment solution, the mass of the silane coupling agent is 100%, and the mass of the ethanol is 80-95%. Preferably, the first drying is carried out at 18-35°C for 36-60 hours, and then at 100-110°C for 2-4 hours.

6. The preparation method according to claim 5, characterized in that, The reaction temperature is 30-50℃; Preferably, the reaction time is 2-4 hours; Preferably, the reaction is carried out in the presence of an organic solvent; Preferably, the mass ratio of the organic solvent to titanium dioxide is (2-5):1; Preferably, the reaction further includes a second drying step after completion; Preferably, the temperature for the second drying is 50-80°C; Preferably, the second drying time is 4-8 hours.

7. The preparation method according to claim 5 or 6, characterized in that, Before the modification in step (1), the titanium dioxide is pretreated. The pretreatment includes calcination, alkaline cleaning, third drying and grinding in sequence. Preferably, the calcination temperature is 400-500℃; Preferably, the roasting time is 1-3 hours; Preferably, the temperature of the third drying step is 100-150°C; Preferably, the third drying time is 2-4 hours.

8. A resin composition, characterized in that, The resin composition comprises the modified titanium dioxide, thermosetting resin, and curing agent as described in any one of claims 1-3.

9. The resin composition according to claim 8, characterized in that, The thermosetting resin includes epoxy resin or cyanate ester resin; Preferably, the modified titanium dioxide comprises 5-50% by weight, based on 100% of the mass of the thermosetting resin; Preferably, the curing agent comprises methyltetrahydrophthalic anhydride and / or phthalic anhydride; Preferably, the curing agent comprises 30-40% of the mass of the thermosetting resin, which is 100% of the total mass.

10. A white LED backlight panel, characterized in that, The raw materials for preparing the white LED backlight panel include the resin composition as described in claim 8 or 9.

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