Functionalized titanium dioxide papermaking filler and its preparation method and application

Abstract

The present invention provides a functionalized titanium dioxide papermaking filler and its preparation method and application. The raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight, 45-55 parts by weight of rutile titanium dioxide, 3-6 parts by weight of reactive dye, 2-8 parts by weight of cationic reagent, 1-2 parts by weight of potassium aluminum sulfate dodecahydrate, 4-7 parts by weight of sodium silicate, 3-4 parts by weight of silicon nitride, 1-2 parts by weight of silane coupling agent, 2-5 parts by weight of dyeing auxiliary, 2-5 parts by weight of dispersant, 2-5 parts by weight of defoamer, 20-30 parts by weight of ammonia water with a mass concentration of 15-25%, and 135-165 parts by weight of deionized water. The functionalized titanium dioxide papermaking filler has better weather resistance and more flexible paper coloring and tinting properties. When the functionalized titanium dioxide papermaking filler is used to make various papers, the fluorescence intensity of the obtained paper can also be effectively reduced, meeting the special functionalization requirements of the filler.

Description

Technical Field

[0001] The invention relates to a functionalized titanium dioxide papermaking filler and a preparation method and application thereof, belonging to the technical field of papermaking. Background Art

[0002] Titanium dioxide, as a paper filler, is widely used in the production of specialty papers and high-end security papers. Traditional titanium dioxide fillers used in papermaking are generally unsurface-treated anatase titanium dioxide, while some types of paper use rutile titanium dioxide as a filler. However, the inherent defects of these fillers significantly impact their application in paper. For example, traditional titanium dioxide fillers exhibit certain color defects. Even trace amounts of impurities can cause severe discoloration, making it impossible to achieve subtle, light colors on paper, resulting in a lack of texture and a monotonous, unsaturated hue. Typical titanium dioxide fillers, exposed to the combined effects of sunlight, oxygen, water, and temperature, can experience aging phenomena such as yellowing, gloss loss, powdering, and weight loss, impacting their filler performance. Titanium dioxide particles are typically submicron, highly polar, and have a high specific surface area. They are prone to aggregates, which can affect the paper's tinting strength, gloss, and other application properties. They also affect their uniformity of distribution and are unable to mitigate the fluorescent photosensitivity of certain papers.

[0003] Currently, there is limited research in the field on modifying titanium dioxide fillers for papermaking to achieve properties such as superior weather resistance, more flexible coloration and colorability, and effective reduction of paper fluorescence, with no reports on similar technologies. Based on the application of specialty papers and high-end anti-counterfeiting paper, a comprehensive evaluation of the functional requirements of titanium dioxide fillers was conducted to develop a functionalized titanium dioxide papermaking filler that combines excellent weather resistance, flexible coloration and color reduction stability, and good paper distribution uniformity, thereby effectively reducing paper fluorescence. This is of great value. Summary of the Invention

[0004] In order to solve the above-mentioned shortcomings and deficiencies, one object of the present invention is to provide a functionalized titanium dioxide papermaking filler.

[0005] Another object of the present invention is to provide a method for preparing the functionalized titanium dioxide papermaking filler described above.

[0006] Another object of the present invention is to provide the use of the above-mentioned functionalized titanium dioxide papermaking filler in the production of special paper.

[0007] In order to achieve the above objectives, on the one hand, the present invention provides a functionalized titanium dioxide papermaking filler, wherein the raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight:

[0008] 45-55 parts by weight of rutile titanium dioxide, 3-6 parts by weight of reactive dye, 2-8 parts by weight of cationic agent, 1-2 parts by weight of potassium aluminum sulfate dodecahydrate, 4-7 parts by weight of sodium silicate, 3-4 parts by weight of silicon nitride, 1-2 parts by weight of silane coupling agent, 2-5 parts by weight of dyeing auxiliary, 2-5 parts by weight of dispersant, 2-5 parts by weight of defoaming agent, 20-30 parts by weight of ammonia water with a mass concentration of 15-25%, and 135-165 parts by weight of deionized water.

[0009] As a specific embodiment of the functionalized titanium dioxide papermaking filler described above in the present invention, the raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight:

[0010] 45 parts by weight of rutile titanium dioxide, 3 parts by weight of reactive dye, 2 parts by weight of cationic agent, 1 part by weight of silane coupling agent, 1 part by weight of potassium aluminum sulfate dodecahydrate, 4 parts by weight of sodium silicate, 3 parts by weight of silicon nitride, 2 parts by weight of dyeing auxiliary, 2 parts by weight of dispersant, 2 parts by weight of defoaming agent, 20 parts by weight of ammonia water with a mass concentration of 15-25%, and 135 parts by weight of deionized water.

[0011] As a specific embodiment of the functionalized titanium dioxide papermaking filler described above in the present invention, the raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight:

[0012] 48 parts by weight of rutile titanium dioxide, 4 parts by weight of reactive dye, 4 parts by weight of cationic agent, 1 part by weight of silane coupling agent, 1 part by weight of potassium aluminum sulfate dodecahydrate, 5 parts by weight of sodium silicate, 3 parts by weight of silicon nitride, 3 parts by weight of dyeing auxiliary, 3 parts by weight of dispersant, 3 parts by weight of defoaming agent, 24 parts by weight of ammonia water with a mass concentration of 15-25%, and 144 parts of deionized water.

[0013] As a specific embodiment of the functionalized titanium dioxide papermaking filler described above in the present invention, the raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight:

[0014] 50 parts by weight of rutile titanium dioxide, 5 parts by weight of reactive dye, 6 parts by weight of cationic agent, 2 parts by weight of silane coupling agent, 2 parts by weight of potassium aluminum sulfate dodecahydrate, 6 parts by weight of sodium silicate, 4 parts by weight of silicon nitride, 4 parts by weight of dyeing auxiliary, 4 parts by weight of dispersant, 4 parts by weight of defoaming agent, 28 parts by weight of ammonia water with a mass concentration of 15-25%, and 150 parts by weight of deionized water.

[0015] As a specific embodiment of the functionalized titanium dioxide papermaking filler described above in the present invention, the raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight:

[0016] 55 parts by weight of rutile titanium dioxide, 6 parts by weight of reactive dye, 8 parts by weight of cationic agent, 2 parts by weight of silane coupling agent, 2 parts by weight of potassium aluminum sulfate dodecahydrate, 7 parts by weight of sodium silicate, 4 parts by weight of silicon nitride, 5 parts by weight of dyeing auxiliary, 5 parts by weight of dispersant, 5 parts by weight of defoaming agent, 30 parts by weight of ammonia water with a mass concentration of 15-25%, and 165 parts by weight of deionized water.

[0017] As a specific embodiment of the functionalized titanium dioxide papermaking filler described above in the present invention, the reactive dye includes one or a combination of reactive bright yellow K-6G, reactive red 3BF, reactive golden yellow 3RS and reactive turquoise blue K-GL.

[0018] As a specific embodiment of the functionalized titanium dioxide papermaking filler described above, the cationic agent includes one or a combination of polydiallyldimethylammonium chloride, dimethyldiallylammonium chloride and cationic polyacrylamide.

[0019] As a specific embodiment of the functionalized titanium dioxide papermaking filler described above in the present invention, the silane coupling agent includes one or a combination of γ-methacryloxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane.

[0020] As a specific embodiment of the functionalized titanium dioxide papermaking filler described above in the present invention, the dispersant includes one or a combination of polyethylene oxide and polycarboxylate.

[0021] As a specific embodiment of the functionalized titanium dioxide papermaking filler described above, the defoaming agent includes one or a combination of polydimethylsiloxane and emulsified silicone oil, etc. The emulsified silicone oil used in the present invention is a conventional material.

[0022] As a specific embodiment of the functionalized titanium dioxide papermaking filler described above in the present invention, the dyeing auxiliary agent includes one or a combination of sulphur dioxide, sodium chloride and acetic acid.

[0023] On the other hand, the present invention also provides a method for preparing the functionalized titanium dioxide papermaking filler described above, wherein the preparation method comprises:

[0024] Step 1: adding rutile titanium dioxide to deionized water, and preparing a titanium dioxide slurry under heating and stirring conditions; then adding sodium silicate and silicon nitride to the titanium dioxide slurry and continuing to heat and stir, so that the sodium silicate performs silicon coating treatment on the rutile titanium dioxide and silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride;

[0025] Step 2: Adding a reactive dye and a dyeing auxiliary into deionized water, and preparing a dyeing solution under heating and stirring conditions; adding the silicon-coated rutile titanium dioxide and silicon nitride into the dyeing solution and continuously heating and stirring; then adding potassium aluminum sulfate dodecahydrate and continuing to stir to fully dye the rutile titanium dioxide;

[0026] Step 3: After the solution obtained in step 2 is allowed to settle, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered. The titanium dioxide paste obtained after filtration is then added to deionized water to prepare a titanium dioxide paste aqueous solution, and then ammonia water with a mass concentration of 15-25% is added under stirring to adjust the pH value of the system;

[0027] Step 4: Add the cationic reagent, dispersant, and silane coupling agent to the solution obtained in step 3 in sequence, mix them evenly under heating and stirring conditions, then add the defoaming agent and continue stirring to mix them evenly;

[0028] Step 5: Dry the mixed solution obtained in step 4 to obtain the functionalized titanium dioxide papermaking filler.

[0029] As a specific embodiment of the preparation method described above, there is no specific requirement for the order of adding sodium silicate and silicon nitride in step 1, and the order of adding the two can be reasonably adjusted according to the actual operation needs on site.

[0030] As a specific embodiment of the preparation method described above of the present invention, wherein, in step 1: the heating and stirring conditions are: temperature of 80° C., rotation speed of 500-600 rpm, and stirring time of 1-1.5 h;

[0031] The conditions for continuous heating and stirring are: temperature 80° C., rotation speed 500 rpm, and stirring time 1 h.

[0032] In the present invention, sodium silicate and silicon nitride are added to the titanium dioxide slurry in step 1 and continuously heated and stirred. There are many unbonded hydroxyl groups on the surface of the rutile titanium dioxide particles, which can polymerize with the hydroxyl groups of the hydrated oxide (silicon hydroxyl and hydroxide ion composition) to form hydroxyl bridges, thereby generating a hydroxide coating layer. At the same time, a uniform and dense coating layer, i.e., a silicon coating, is formed between the coating layer and the nano-TiO2 particles. Furthermore, unlike traditional silicon coating processes, the present invention further adds silicon nitride to the rutile titanium dioxide. The silicon coating can tightly coat the silicon nitride and rutile titanium dioxide together, thereby further improving the weather resistance of the rutile titanium dioxide without affecting other properties of the rutile titanium dioxide, thereby expanding its scope of application and having significant effects.

[0033] As a specific embodiment of the preparation method described above of the present invention, wherein, in step 2: the heating and stirring conditions are: temperature of 70° C., rotation speed of 300-500 rpm, and stirring time of 1-1.5 h;

[0034] The conditions for continuous heating and stirring are: temperature 70° C., rotation speed 300 rpm, and stirring time 1 h;

[0035] The stirring time is continued for 0.5 h.

[0036] In step 2, the potassium aluminum sulfate dodecahydrate is a very good mordant and can promote the dyeing of rutile titanium dioxide.

[0037] In step 2, the silicon-coated rutile titanium dioxide and silicon nitride are added to the dyeing solution and continuously heated and stirred. At this time, the reactive dye and the dyeing auxiliary penetrate the silicon coating to dye the rutile titanium dioxide.

[0038] As a specific embodiment of the above preparation method of the present invention, in step 3: adjusting the pH value of the system is adjusting the pH value of the system to 8-9.

[0039] As a specific embodiment of the preparation method described above, the amounts of the deionized water in step 1, the deionized water in step 2, and the deionized water used to prepare the titanium dioxide paste aqueous solution in step 3 are the same, all being 45-55 parts by weight.

[0040] In addition, the present invention does not make specific requirements on the amount of deionized water used for rinsing in step 3, and can be reasonably adjusted according to the actual rinsing conditions on site, as long as the purpose of rinsing can be achieved. As a specific embodiment of the preparation method described above of the present invention, wherein, in step 4: the heating and stirring conditions are: temperature 60°C, rotation speed 300 rpm, stirring time 1 hour;

[0041] The stirring conditions are as follows: a rotation speed of 300 rpm and a stirring time of 2 h.

[0042] In step 4, a cationic reagent, a dispersant, and a silane coupling agent are sequentially added to the solution obtained in step 3, and the mixture is uniformly mixed under heating and stirring conditions. At this time, the cationic reagent and the silane coupling agent respectively perform cationization treatment and coating modification on the silicon-coated rutile titanium dioxide and silicon nitride as a whole.

[0043] In the present invention, the stirring involved in steps 1 to 4 may be magnetic stirring.

[0044] As a specific embodiment of the above preparation method of the present invention, in step 5: the drying is carried out at 85° C. for 2 hours.

[0045] The present invention does not impose any specific requirements on the size of the functionalized titanium dioxide papermaking filler obtained in step 5. The size can be reasonably adjusted according to the actual operation needs on site, as long as the purpose of the present invention can be achieved.

[0046] The functionalized titanium dioxide papermaking filler involved in the present invention is very complex. The raw material components used therein cooperate and interact with each other. Changes in one or several raw material components, or only changing the amount of one raw material component when the raw material components remain unchanged, will cause fundamental changes in the paper color, tintability, weather resistance and other properties of the functionalized titanium dioxide papermaking filler. Even just slight changes in the operating steps and preparation conditions such as temperature during the preparation process will cause fundamental changes in the properties of the functionalized titanium dioxide papermaking filler.

[0047] In another aspect, the present invention also provides the use of the functionalized titanium dioxide papermaking filler in the production of special paper.

[0048] As a specific embodiment of the above-mentioned application of the present invention, the special paper includes different types of high-end paper or high-end anti-counterfeiting paper such as coated paper, dictionary paper, decorative paper, etc.

[0049] Compared with the prior art, the functionalized titanium dioxide papermaking filler provided by the present invention can achieve the following beneficial technical effects:

[0050] The raw materials used in the functionalized titanium dioxide papermaking filler provided by the present invention are all natural-grade raw materials, do not contain strong acids or strong alkalis, are non-toxic and harmless, and are in line with the concept of green environmental protection.

[0051] The present invention uses reactive dyes to dye rutile titanium dioxide to improve its tinting power stability; then, impurities are removed by filtration to further improve the purity of the product; finally, a silane coupling agent is used as a coating material to coat and modify the silicon-coated rutile titanium dioxide and silicon nitride as a whole to solve the problem of reduced dispersibility of rutile titanium dioxide particles after dyeing, thereby improving the dispersibility of the functionalized titanium dioxide papermaking filler finally prepared.

[0052] The present invention adopts reactive dyes of different colors to dye rutile titanium dioxide, which can give the paper maximum flexibility in color matching, expand the color space and application range of the paper, and make it suitable for the production of different types of high-end paper or high-end anti-counterfeiting paper such as coated paper, dictionary paper, decorative paper, etc.

[0053] The cationic reagent used in the present invention can change the charge of the silicon-coated rutile titanium dioxide and silicon nitride as a whole. In addition to changing the charge, it can also promote the dyeing of rutile titanium dioxide and improve the stability of the dyeing solution to a certain extent.

[0054] The polyethylene oxide and polycarboxylate used in the present invention are both good dispersants. By using these two dispersants, various other additives can be dispersed more evenly in the titanium dioxide slurry.

[0055] The polydimethylsiloxane and emulsified silicone oil used in the present invention have extremely stable chemical properties and are non-toxic and harmless, and are very good defoaming agents.

[0056] In summary, the present invention first uses a silicon coating / silicon film formed by sodium silicate to coat the rutile titanium dioxide and silicon nitride as a whole, then dyes them with reactive dyes, and finally performs cationization treatment and coating modification on the rutile titanium dioxide and silicon nitride coated with the silicon coating as a whole, so that the functionalized titanium dioxide papermaking filler finally obtained has better weather resistance and more flexible paper coloring properties. At the same time, the functionalized titanium dioxide papermaking filler is used to make various papers, which can also effectively reduce the fluorescence intensity of the paper and meet the special functionalization requirements of the filler. It can be seen that the functionalized titanium dioxide papermaking filler has a wide range of applications and good economic benefits. In addition, the preparation method of the functionalized titanium dioxide papermaking filler provided by the present invention is simple to operate and highly practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0058] Figure 1 Schematic diagram of the reaction principle of surface modification of TiO2 by γ-methacryloxypropyltrimethoxysilane in an embodiment of the present invention.

[0059] Figure 2 This is a potential analysis diagram of the modified titanium dioxide solution obtained in Example 3 of the present invention (i.e., the mixed solution obtained in step 4).

[0060] Figure 3 This is a potential analysis diagram of the modified titanium dioxide solution obtained in Example 3 of the present invention after long-term standing (i.e., after the mixed solution obtained in step 4 is allowed to stand for 30 minutes). DETAILED DESCRIPTION

[0061] It should be noted that the term "comprise" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or apparatus.

[0062] The "range" disclosed in the present invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits, and one or more upper limits respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundaries of a particular range. All ranges defined in this way are combinable, i.e., any lower limit can be combined with any upper limit to form a range. For example, a range of 60-120 and 80-110 is listed for a particular parameter, and it is understood that a range of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​listed are 1 and 2, and the maximum range values ​​listed are 3, 4, and 5, then the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0063] In the present invention, unless otherwise specified, the numerical range "ab" is an abbreviation for any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed in this invention, and "0-5" is merely an abbreviation for these numerical combinations.

[0064] In the present invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in the present invention can be combined with each other to form a new technical solution.

[0065] In the present invention, unless otherwise specified, all technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

[0066] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and Examples. The following embodiments are part of the present invention, rather than all of the embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0067] Example 1

[0068] This embodiment provides a functionalized titanium dioxide papermaking filler, wherein the raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight:

[0069] 45 parts by weight of rutile titanium dioxide, 3 parts by weight of a reactive dye (Reactive Light Yellow K-6G), 2 parts by weight of a cationic agent (polydiallyldimethylammonium chloride), 1 part by weight of a silane coupling agent (γ-methacryloxypropyltrimethoxysilane), 1 part by weight of potassium aluminum sulfate dodecahydrate, 4 parts by weight of sodium silicate, 3 parts by weight of silicon nitride, 2 parts by weight of a dyeing auxiliary (sodium sulfate), 2 parts by weight of a dispersant (polyethylene oxide), 2 parts by weight of a defoaming agent (polydimethylsiloxane), 20 parts by weight of 20% ammonia water, and 135 parts by weight of deionized water;

[0070] The functionalized titanium dioxide papermaking filler is prepared using the above components as raw materials and a preparation method comprising the following steps:

[0071] Step 1: Add 45 parts by weight of rutile titanium dioxide to 45 parts by weight of deionized water, heat to 80° C. and stir continuously to prepare a titanium dioxide slurry, then add 4 parts by weight of sodium silicate and 3 parts by weight of silicon nitride to the titanium dioxide slurry, and stir magnetically at 80° C. The speed is controlled to 500 rpm and the stirring time is 1 hour, so that the sodium silicate performs silicon coating treatment on the rutile titanium dioxide and the silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride;

[0072] Step 2: Add 3 parts by weight of a reactive dye and 2 parts by weight of a dyeing auxiliary to 45 parts by weight of deionized water, heat to 70° C. and stir continuously to prepare a dyeing solution, dissolve the silicon-coated rutile titanium dioxide and silicon nitride obtained in step 1 in the dyeing solution, and stir magnetically at 70° C., control the speed to 300 rpm, and stir for 1 hour; then add 1 part by weight of potassium aluminum sulfate dodecahydrate and stir for 0.5 hour to fully dye the rutile titanium dioxide;

[0073] Step 3: After the solution obtained in step 2 is allowed to settle for 1 hour, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered in a suction filter; the titanium dioxide paste obtained after the filtration is added to 45 parts by weight of deionized water to prepare a titanium dioxide paste aqueous solution, and 20 parts by weight of 20% ammonia water is added to the titanium dioxide paste aqueous solution while stirring to adjust the pH value of the system to between 8 and 9;

[0074] Step 4: Add 2 parts by weight of a cationic reagent, 2 parts by weight of a dispersant, and 1 part by weight of a silane coupling agent to the solution obtained in step 3, stir magnetically at 60°C and 300 rpm for 1 hour to mix thoroughly, then add 2 parts by weight of a defoaming agent and stir at 300 rpm for 2 hours to mix thoroughly;

[0075] Step 5: The mixed solution obtained in step 4 was allowed to stand for 30 minutes, and then its potential value was measured. Then, it was dried in an oven at a temperature of 85° C. for 2 hours to obtain the functionalized titanium dioxide papermaking filler particles.

[0076] Example 2

[0077] This embodiment provides a functionalized titanium dioxide papermaking filler, wherein the raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight:

[0078] 48 parts by weight of rutile titanium dioxide, 4 parts by weight of a reactive dye (Reactive Light Yellow K-6G), 4 parts by weight of a cationic agent (polydiallyldimethylammonium chloride), 1 part by weight of a silane coupling agent (γ-methacryloxypropyltrimethoxysilane), 1 part by weight of potassium aluminum sulfate dodecahydrate, 5 parts by weight of sodium silicate, 3 parts by weight of silicon nitride, 3 parts by weight of a dyeing auxiliary (sodium sulfate), 3 parts by weight of a dispersant (polyethylene oxide), 3 parts by weight of a defoaming agent (polydimethylsiloxane), 24 parts by weight of 15% ammonia water, and 144 parts by weight of deionized water;

[0079] The functionalized titanium dioxide papermaking filler is prepared using the above components as raw materials and a preparation method comprising the following steps:

[0080] Step 1: adding 48 parts by weight of rutile titanium dioxide to 48 parts by weight of deionized water, heating to 80° C. and stirring continuously to prepare a titanium dioxide slurry, then adding 5 parts by weight of sodium silicate and 3 parts by weight of silicon nitride to the titanium dioxide slurry, and magnetically stirring at 80° C., and controlling the speed to 500 rpm for 1 hour, so that the sodium silicate performs silicon coating treatment on the rutile titanium dioxide and the silicon nitride as a whole, to obtain silicon-coated rutile titanium dioxide and silicon nitride;

[0081] Step 2: 4 parts by weight of a reactive dye and 3 parts by weight of a dyeing auxiliary are added to 48 parts by weight of deionized water, heated to 70° C. and continuously stirred to prepare a dyeing solution, the silicon-coated rutile titanium dioxide and silicon nitride obtained in step 1 are dissolved in the dyeing solution, and magnetic stirring is performed at 70° C., and the speed is controlled to be 300 rpm for 1 hour; then 1 part by weight of potassium aluminum sulfate dodecahydrate is added and stirred for 0.5 hour to fully dye the rutile titanium dioxide;

[0082] Step 3: After the solution obtained in step 2 is allowed to settle for 1 hour, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered in a suction filter; the titanium dioxide paste obtained after the filtration is added to 48 parts by weight of deionized water to prepare a titanium dioxide paste aqueous solution, and 24 parts by weight of 15% ammonia water is added to the titanium dioxide paste aqueous solution while stirring to adjust the pH value of the system to between 8 and 9;

[0083] Step 4: To the solution obtained in step 3, 4 parts by weight of a cationic reagent, 3 parts by weight of a dispersant, and 1 part by weight of a silane coupling agent were added in sequence, and the mixture was magnetically stirred at 60° C. and 300 rpm for 1 hour to completely mix. 3 parts by weight of a defoaming agent was then added, and the mixture was stirred at 300 rpm for 2 hours to completely mix.

[0084] Step 5: The mixed solution obtained in step 4 was allowed to stand for 30 minutes, and then its potential value was measured. Then, it was dried in an oven at a temperature of 85° C. for 2 hours to obtain the functionalized titanium dioxide papermaking filler particles.

[0085] Example 3

[0086] This embodiment provides a functionalized titanium dioxide papermaking filler, wherein the raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight:

[0087] 50 parts by weight of rutile titanium dioxide, 5 parts by weight of a reactive dye (Reactive Light Yellow K-6G), 6 parts by weight of a cationic agent (polydiallyldimethylammonium chloride), 2 parts by weight of a silane coupling agent (γ-methacryloxypropyltrimethoxysilane), 2 parts by weight of potassium aluminum sulfate dodecahydrate, 6 parts by weight of sodium silicate, 4 parts by weight of silicon nitride, 4 parts by weight of a dyeing auxiliary (sodium sulfate), 4 parts by weight of a dispersant (polyethylene oxide), 4 parts by weight of a defoaming agent (polydimethylsiloxane), 28 parts by weight of 20% ammonia water, and 150 parts by weight of deionized water;

[0088] The functionalized titanium dioxide papermaking filler is prepared using the above components as raw materials and a preparation method comprising the following steps:

[0089] Step 1: Add 50 parts by weight of rutile titanium dioxide to 50 parts by weight of deionized water, heat to 80° C. and stir continuously to prepare a titanium dioxide slurry, then add 6 parts by weight of sodium silicate and 4 parts by weight of silicon nitride to the titanium dioxide slurry, and stir magnetically at 80° C., control the speed to 500 rpm, and stir for 1 hour, so that the sodium silicate silicon-coates the rutile titanium dioxide and silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride;

[0090] Step 2: Add 5 parts by weight of a reactive dye and 4 parts by weight of a dyeing auxiliary to 50 parts by weight of deionized water, heat to 70° C. and stir continuously to prepare a dyeing solution, dissolve the silicon-coated rutile titanium dioxide and silicon nitride obtained in step 1 in the dyeing solution, and stir magnetically at 70° C., control the speed to 300 rpm, and stir for 1 hour; then add 2 parts by weight of potassium aluminum sulfate dodecahydrate and stir for 0.5 hour to fully dye the rutile titanium dioxide;

[0091] Step 3: After the solution obtained in step 2 is allowed to settle for 1 hour, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered in a suction filter; the titanium dioxide paste obtained after the filtration is added to 50 parts by weight of deionized water to prepare a titanium dioxide paste aqueous solution, and 28 parts by weight of 20% ammonia water is added to the titanium dioxide paste aqueous solution while stirring to adjust the pH value of the system to between 8 and 9;

[0092] Step 4: 6 parts by weight of a cationic reagent, 4 parts by weight of a dispersant, and 2 parts by weight of a silane coupling agent were added to the solution obtained in step 3, and the mixture was magnetically stirred at 60°C and 300 rpm for 1 hour to completely mix. 4 parts by weight of a defoaming agent was then added, and the mixture was stirred at 300 rpm for 2 hours to completely mix.

[0093] Among them, the schematic diagram of the reaction principle of silane coupling agent to modify the surface of TiO2 is as follows Figure 1 As shown;

[0094] Step 5: The mixed solution obtained in step 4 was allowed to stand for 30 minutes, and then its potential value was measured. Then, it was dried in an oven at a temperature of 85° C. for 2 hours to obtain the functionalized titanium dioxide papermaking filler particles.

[0095] Example 4

[0096] This embodiment provides a functionalized titanium dioxide papermaking filler, wherein the raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight:

[0097] 55 parts by weight of rutile titanium dioxide, 6 parts by weight of reactive dye (Reactive Light Yellow K-6G), 8 parts by weight of cationic agent (polydiallyldimethylammonium chloride), 2 parts by weight of silane coupling agent (γ-methacryloxypropyltrimethoxysilane), 2 parts by weight of potassium aluminum sulfate dodecahydrate, 7 parts by weight of sodium silicate, 4 parts by weight of silicon nitride, 5 parts by weight of dyeing auxiliary (sulfate sulfate), 5 parts by weight of dispersant (polyethylene oxide), 5 parts by weight of defoaming agent (polydimethylsiloxane), 30 parts by weight of 20% ammonia water, and 165 parts by weight of deionized water;

[0098] The functionalized titanium dioxide papermaking filler is prepared using the above components as raw materials and a preparation method comprising the following steps:

[0099] Step 1: 55 parts by weight of rutile titanium dioxide is added to 55 parts by weight of deionized water, heated to 80° C. and continuously stirred to prepare a titanium dioxide slurry, and then 7 parts by weight of sodium silicate and 4 parts by weight of silicon nitride are added to the titanium dioxide slurry, and magnetic stirring is performed at 80° C. The speed is controlled to be 500 rpm and the stirring time is 1 hour, so that the sodium silicate performs silicon coating treatment on the rutile titanium dioxide and the silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride;

[0100] Step 2: 6 parts by weight of a reactive dye and 5 parts by weight of a dyeing auxiliary are added to 55 parts by weight of deionized water, heated to 70° C. and continuously stirred to prepare a dyeing solution, the silicon-coated rutile titanium dioxide and silicon nitride obtained in step 1 are dissolved in the dyeing solution, and magnetic stirring is performed at 70° C., and the speed is controlled to be 300 rpm for 1 hour; then 2 parts by weight of potassium aluminum sulfate dodecahydrate are added and stirred for 0.5 hour to fully dye the rutile titanium dioxide;

[0101] Step 3: After the solution obtained in step 2 is allowed to settle for 1 hour, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered in a suction filter; the titanium dioxide paste obtained after the filtration is added to 55 parts by weight of deionized water to prepare a titanium dioxide paste aqueous solution, and 30 parts by weight of 20% ammonia water is added to the titanium dioxide paste aqueous solution while stirring to adjust the pH value of the system to between 8 and 9;

[0102] Step 4: 8 parts by weight of a cationic reagent, 5 parts by weight of a dispersant, and 2 parts by weight of a silane coupling agent were added to the solution obtained in step 3, and the mixture was stirred magnetically at 60°C and 300 rpm for 1 hour to completely mix. 5 parts by weight of a defoaming agent was then added, and the mixture was stirred at 300 rpm for 2 hours to completely mix.

[0103] Step 5: The mixed solution obtained in step 4 was allowed to stand for 30 minutes, and then its potential value was measured. Then, it was dried in an oven at a temperature of 85° C. for 2 hours to obtain the functionalized titanium dioxide papermaking filler particles.

[0104] Example 5

[0105] This embodiment provides a functionalized titanium dioxide papermaking filler, wherein the raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight:

[0106] 50 parts by weight of rutile titanium dioxide, 5 parts by weight of a reactive dye (Reactive Light Yellow K-6G), 6 parts by weight of a cationic agent (dimethyldiallylammonium chloride), 2 parts by weight of a silane coupling agent (γ-methacryloxypropyltrimethoxysilane), 2 parts by weight of potassium aluminum sulfate dodecahydrate, 6 parts by weight of sodium silicate, 4 parts by weight of silicon nitride, 4 parts by weight of a dyeing auxiliary (sodium sulfate), 4 parts by weight of a dispersant (polyethylene oxide), 4 parts by weight of a defoaming agent (polydimethylsiloxane), 28 parts by weight of 20% ammonia water, and 150 parts by weight of deionized water;

[0107] The functionalized titanium dioxide papermaking filler is prepared using the above components as raw materials and a preparation method comprising the following steps:

[0108] Step 1: Add 50 parts by weight of rutile titanium dioxide to 50 parts by weight of deionized water, heat to 80° C. and stir continuously to prepare a titanium dioxide slurry, then add 6 parts by weight of sodium silicate and 4 parts by weight of silicon nitride to the titanium dioxide slurry, and stir magnetically at 80° C., control the speed to 500 rpm, and stir for 1 hour, so that the sodium silicate silicon-coates the rutile titanium dioxide and silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride;

[0109] Step 2: Add 5 parts by weight of a reactive dye and 4 parts by weight of a dyeing auxiliary to 50 parts by weight of deionized water, heat to 70° C. and stir continuously to prepare a dyeing solution, dissolve the silicon-coated rutile titanium dioxide and silicon nitride obtained in step 1 in the dyeing solution, and stir magnetically at 70° C., control the speed to 300 rpm, and stir for 1 hour; then add 2 parts by weight of potassium aluminum sulfate dodecahydrate and stir for 0.5 hour to fully dye the rutile titanium dioxide;

[0110] Step 3: After the solution obtained in step 2 is allowed to settle for 1 hour, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered in a suction filter; the titanium dioxide paste obtained after the filtration is added to 50 parts by weight of deionized water to prepare a titanium dioxide paste aqueous solution, and 28 parts by weight of 20% ammonia water is added to the titanium dioxide paste aqueous solution while stirring to adjust the pH value of the system to between 8 and 9;

[0111] Step 4: 6 parts by weight of a cationic reagent, 4 parts by weight of a dispersant, and 2 parts by weight of a silane coupling agent were added to the solution obtained in step 3, and the mixture was magnetically stirred at 60°C and 300 rpm for 1 hour to completely mix. 4 parts by weight of a defoaming agent was then added, and the mixture was stirred at 300 rpm for 2 hours to completely mix.

[0112] Step 5: The mixed solution obtained in step 4 was allowed to stand for 30 minutes, and then its potential value was measured. Then, it was dried in an oven at a temperature of 85° C. for 2 hours to obtain the functionalized titanium dioxide papermaking filler.

[0113] Comparative Example 1

[0114] This comparative example provides a modified titanium dioxide papermaking filler, wherein the raw material composition of the modified titanium dioxide papermaking filler comprises, by weight:

[0115] 50 parts by weight of rutile titanium dioxide, 5 parts by weight of a reactive dye (Reactive Light Yellow K-6G), 6 parts by weight of a cationic agent (polydiallyldimethylammonium chloride), 2 parts by weight of a silane coupling agent (γ-methacryloxypropyltrimethoxysilane), 2 parts by weight of potassium aluminum sulfate dodecahydrate, 6 parts by weight of sodium silicate, 4 parts by weight of silicon nitride, 4 parts by weight of a dyeing auxiliary (sodium sulfate), 4 parts by weight of a dispersant (polyethylene oxide), 4 parts by weight of a defoaming agent (polydimethylsiloxane), 28 parts by weight of 20% ammonia water, and 150 parts by weight of deionized water;

[0116] The modified titanium dioxide papermaking filler is prepared using the above components as raw materials and a preparation method comprising the following steps:

[0117] Step 1: Add 50 parts by weight of rutile titanium dioxide to 50 parts by weight of deionized water, heat to 80° C. and stir continuously to prepare a titanium dioxide slurry, then add 6 parts by weight of sodium silicate and 4 parts by weight of silicon nitride to the titanium dioxide slurry, and stir magnetically at 80° C., control the speed to 500 rpm, and stir for 1 hour, so that the sodium silicate silicon-coates the rutile titanium dioxide and silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride;

[0118] Step 2: Add 5 parts by weight of a reactive dye and 4 parts by weight of a dyeing auxiliary to 50 parts by weight of deionized water, heat to 80° C. and stir continuously to prepare a dyeing solution, dissolve the silicon-coated rutile titanium dioxide and silicon nitride obtained in step 1 in the dyeing solution, and stir magnetically at 70° C., control the speed to 300 rpm, and stir for 1 hour; then add 2 parts by weight of potassium aluminum sulfate dodecahydrate and stir for 0.5 hour to fully dye the rutile titanium dioxide;

[0119] Step 3: After the solution obtained in step 2 is allowed to settle for 1 hour, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered in a suction filter; the titanium dioxide paste obtained after the filtration is added to 50 parts by weight of deionized water to prepare a titanium dioxide paste aqueous solution, and 28 parts by weight of 20% ammonia water is added to the titanium dioxide paste aqueous solution while stirring to adjust the pH value of the system to between 8 and 9;

[0120] Step 4: 6 parts by weight of a cationic reagent, 4 parts by weight of a dispersant, and 2 parts by weight of a silane coupling agent were added to the solution obtained in step 3, and the mixture was magnetically stirred at 60°C and 300 rpm for 1 hour to completely mix. 4 parts by weight of a defoaming agent was then added, and the mixture was stirred at 300 rpm for 2 hours to completely mix.

[0121] Step 5: The mixed solution obtained in step 4 was allowed to stand for 30 minutes, and then its potential value was measured. It was then dried in an oven at 85° C. for 2 hours to obtain the modified titanium dioxide papermaking filler.

[0122] Comparative Example 2

[0123] This comparative example provides a modified titanium dioxide papermaking filler, wherein the raw material composition of the modified titanium dioxide papermaking filler comprises, by weight:

[0124] 50 parts by weight of rutile titanium dioxide, 5 parts by weight of a reactive dye (Reactive Light Yellow K-6G), 6 parts by weight of a cationic agent (polydiallyldimethylammonium chloride), 2 parts by weight of a silane coupling agent (γ-methacryloxypropyltrimethoxysilane), 2 parts by weight of potassium aluminum sulfate dodecahydrate, 6 parts by weight of sodium silicate, 4 parts by weight of silicon nitride, 4 parts by weight of a dyeing auxiliary (sodium sulfate), 4 parts by weight of a dispersant (polyethylene oxide), 4 parts by weight of a defoaming agent (polydimethylsiloxane), 28 parts by weight of 20% ammonia water, and 150 parts by weight of deionized water;

[0125] The modified titanium dioxide papermaking filler is prepared using the above components as raw materials and a preparation method comprising the following steps:

[0126] Step 1: Add 50 parts by weight of rutile titanium dioxide to 50 parts by weight of deionized water, heat to 80° C. and stir continuously to prepare a titanium dioxide slurry, then add 6 parts by weight of sodium silicate and 4 parts by weight of silicon nitride to the titanium dioxide slurry, and stir magnetically at 80° C., control the speed to 500 rpm, and stir for 1 hour, so that the sodium silicate silicon-coates the rutile titanium dioxide and silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride;

[0127] Step 2: Add 5 parts by weight of a reactive dye and 4 parts by weight of a dyeing auxiliary to 50 parts by weight of deionized water, heat to 70° C. and stir continuously to prepare a dyeing solution, dissolve the silicon-coated rutile titanium dioxide and silicon nitride obtained in step 1 in the dyeing solution, and stir magnetically at 60° C., control the speed to 300 rpm, and stir for 1 hour; then add 2 parts by weight of potassium aluminum sulfate dodecahydrate and stir for 0.5 hour to fully dye the rutile titanium dioxide;

[0128] Step 3: After the solution obtained in step 2 is allowed to settle for 1 hour, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered in a suction filter; the titanium dioxide paste obtained after the filtration is added to 50 parts by weight of deionized water to prepare a titanium dioxide paste aqueous solution, and 28 parts by weight of 20% ammonia water is added to the titanium dioxide paste aqueous solution while stirring to adjust the pH value of the system to between 8 and 9;

[0129] Step 4: 6 parts by weight of a cationic reagent, 4 parts by weight of a dispersant, and 2 parts by weight of a silane coupling agent were added to the solution obtained in step 3, and the mixture was magnetically stirred at 60°C and 300 rpm for 1 hour to completely mix. 4 parts by weight of a defoaming agent was then added, and the mixture was stirred at 300 rpm for 2 hours to completely mix.

[0130] Step 5: The mixed solution obtained in step 4 was allowed to stand for 30 minutes, and then its potential value was measured. It was then dried in an oven at 85° C. for 2 hours to obtain the modified titanium dioxide papermaking filler particles.

[0131] Comparative Example 3

[0132] This comparative example provides a modified titanium dioxide papermaking filler, wherein the raw material composition of the modified titanium dioxide papermaking filler comprises, by weight:

[0133] 50 parts by weight of rutile titanium dioxide, 5 parts by weight of reactive dye (Reactive Light Yellow K-6G), 6 parts by weight of cationic agent (polydiallyldimethylammonium chloride), 2 parts by weight of silane coupling agent (γ-methacryloxypropyltrimethoxysilane), 2 parts by weight of potassium aluminum sulfate dodecahydrate, 6 parts by weight of sodium silicate, 4 parts by weight of silicon nitride, 4 parts by weight of dyeing auxiliary (polyethylene oxide), 4 parts by weight of dispersant (sodium sulfate), 4 parts by weight of defoaming agent (polydimethylsiloxane), 28 parts by weight of 20% ammonia water, and 150 parts by weight of deionized water;

[0134] The modified titanium dioxide papermaking filler is prepared using the above components as raw materials and a preparation method comprising the following steps:

[0135] Step 1: Add 50 parts by weight of rutile titanium dioxide to 50 parts by weight of deionized water, heat to 80° C. and stir continuously to prepare a titanium dioxide slurry, then add 6 parts by weight of sodium silicate and 4 parts by weight of silicon nitride to the titanium dioxide slurry, and stir magnetically at 80° C., control the speed to 500 rpm, and stir for 1 hour, so that the sodium silicate silicon-coates the rutile titanium dioxide and silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride;

[0136] Step 2: Add 5 parts by weight of a reactive dye and 4 parts by weight of a dyeing auxiliary to 50 parts by weight of deionized water, heat to 70° C. and stir continuously to prepare a dyeing solution, dissolve the silicon-coated rutile titanium dioxide and silicon nitride obtained in step 1 in the dyeing solution, and stir magnetically at 80° C., control the speed to 300 rpm, and stir for 1 hour; then add 2 parts by weight of potassium aluminum sulfate dodecahydrate and stir for 0.5 hour to fully dye the rutile titanium dioxide;

[0137] Step 3: After the solution obtained in step 2 is allowed to settle for 1 hour, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered in a suction filter; the titanium dioxide paste obtained after the filtration is added to 50 parts by weight of deionized water to prepare a titanium dioxide paste aqueous solution, and 28 parts by weight of 20% ammonia water is added to the titanium dioxide paste aqueous solution while stirring to adjust the pH value of the system to between 8 and 9;

[0138] Step 4: 6 parts by weight of a cationic reagent, 4 parts by weight of a dispersant, and 2 parts by weight of a silane coupling agent were added to the solution obtained in step 3, and the mixture was magnetically stirred at 60°C and 300 rpm for 1 hour to completely mix. 4 parts by weight of a defoaming agent was then added, and the mixture was stirred at 300 rpm for 2 hours to completely mix.

[0139] Step 5: The mixed solution obtained in step 4 was allowed to stand for 30 minutes, and then its potential value was measured. It was then dried in an oven at 85° C. for 2 hours to obtain the modified titanium dioxide papermaking filler particles.

[0140] Comparative Example 4

[0141] This comparative example provides a modified titanium dioxide papermaking filler, wherein the raw material composition of the modified titanium dioxide papermaking filler comprises, by weight:

[0142] 50 parts by weight of rutile titanium dioxide, 5 parts by weight of a reactive dye (Reactive Light Yellow K-6G), 6 parts by weight of a cationic agent (polydiallyldimethylammonium chloride), 2 parts by weight of a silane coupling agent (γ-methacryloxypropyltrimethoxysilane), 2 parts by weight of potassium aluminum sulfate dodecahydrate, 6 parts by weight of sodium silicate, 4 parts by weight of silicon nitride, 4 parts by weight of a dyeing auxiliary (sodium sulfate), 4 parts by weight of a dispersant (polyethylene oxide), 4 parts by weight of a defoaming agent (polydimethylsiloxane), 28 parts by weight of 20% ammonia water, and 150 parts by weight of deionized water;

[0143] The modified titanium dioxide papermaking filler is prepared using the above components as raw materials and a preparation method comprising the following steps:

[0144] Step 1: Add 50 parts by weight of rutile titanium dioxide to 50 parts by weight of deionized water, heat to 80° C. and stir continuously to prepare a titanium dioxide slurry, then add 6 parts by weight of sodium silicate and 4 parts by weight of silicon nitride to the titanium dioxide slurry, and stir magnetically at 80° C., control the speed to 500 rpm, and stir for 1 hour, so that the sodium silicate silicon-coates the rutile titanium dioxide and silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride;

[0145] Step 2: Add 5 parts by weight of a reactive dye and 4 parts by weight of a dyeing auxiliary to 50 parts by weight of deionized water, heat to 70° C. and stir continuously to prepare a dyeing solution, dissolve the silicon-coated rutile titanium dioxide and silicon nitride obtained in step 1 in the dyeing solution, and stir magnetically at 70° C., control the speed to 300 rpm, and stir for 1 hour; then add 2 parts by weight of potassium aluminum sulfate dodecahydrate and stir for 0.5 hour to fully dye the rutile titanium dioxide;

[0146] Step 3: After the solution obtained in step 2 is allowed to settle for 1 hour, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered in a suction filter; the titanium dioxide paste obtained after the filtration is added to 50 parts by weight of deionized water to prepare a titanium dioxide paste aqueous solution, and 28 parts by weight of 20% ammonia water is added to the titanium dioxide paste aqueous solution while stirring to adjust the pH value of the system to between 8 and 9;

[0147] Step 4: 6 parts by weight of a cationic reagent, 4 parts by weight of a dispersant, and 2 parts by weight of a silane coupling agent were sequentially added to the solution obtained in step 3, and magnetically stirred at 300 rpm at 50°C for 1 hour to completely mix them. 4 parts by weight of a defoaming agent was then added, and stirred at 300 rpm for 2 hours to completely mix them.

[0148] Step 5: The mixed solution obtained in step 4 was allowed to stand for 30 minutes, and then its potential value was measured. It was then dried in an oven at 85° C. for 2 hours to obtain the modified titanium dioxide papermaking filler particles.

[0149] Comparative Example 5

[0150] This comparative example provides a modified titanium dioxide papermaking filler, wherein the raw material composition of the modified titanium dioxide papermaking filler comprises, by weight:

[0151] 50 parts by weight of rutile titanium dioxide, 5 parts by weight of a reactive dye (Reactive Light Yellow K-6G), 6 parts by weight of a cationic agent (polydiallyldimethylammonium chloride), 2 parts by weight of a silane coupling agent (γ-methacryloxypropyltrimethoxysilane), 2 parts by weight of potassium aluminum sulfate dodecahydrate, 6 parts by weight of sodium silicate, 4 parts by weight of silicon nitride, 4 parts by weight of a dyeing auxiliary (sodium sulfate), 4 parts by weight of a dispersant (polyethylene oxide), 4 parts by weight of a defoaming agent (polydimethylsiloxane), 28 parts by weight of 20% ammonia water, and 150 parts by weight of deionized water;

[0152] The modified titanium dioxide papermaking filler is prepared using the above components as raw materials and a preparation method comprising the following steps:

[0153] Step 1: Add 50 parts by weight of rutile titanium dioxide to 50 parts by weight of deionized water, heat to 80° C. and stir continuously to prepare a titanium dioxide slurry, then add 6 parts by weight of sodium silicate and 4 parts by weight of silicon nitride to the titanium dioxide slurry, and stir magnetically at 80° C., control the speed to 500 rpm, and stir for 1 hour, so that the sodium silicate silicon-coates the rutile titanium dioxide and silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride;

[0154] Step 2: Add 5 parts by weight of a reactive dye and 4 parts by weight of a dyeing auxiliary to 50 parts by weight of deionized water, heat to 70° C. and stir continuously to prepare a dyeing solution, dissolve the silicon-coated rutile titanium dioxide and silicon nitride obtained in step 1 in the dyeing solution, and stir magnetically at 70° C., control the speed to 300 rpm, and stir for 1 hour; then add 2 parts by weight of potassium aluminum sulfate dodecahydrate and stir for 0.5 hour to fully dye the rutile titanium dioxide;

[0155] Step 3: After the solution obtained in step 2 is allowed to settle for 1 hour, the upper dye solution is discarded, and then the solution is repeatedly rinsed with deionized water several times and filtered in a suction filter; the titanium dioxide paste obtained after the filtration is added to 50 parts by weight of deionized water to prepare a titanium dioxide paste aqueous solution, and 28 parts by weight of 20% ammonia water is added to the titanium dioxide paste aqueous solution while stirring to adjust the pH value of the system to between 8 and 9;

[0156] Step 4: To the solution obtained in step 3, 6 parts by weight of a cationic reagent, 4 parts by weight of a dispersant, and 2 parts by weight of a silane coupling agent were added in sequence, and the mixture was magnetically stirred at 70°C at a speed of 300 rpm for 1 hour to completely mix. 4 parts by weight of a defoaming agent was then added, and the mixture was stirred at a speed of 300 rpm for 2 hours to completely mix.

[0157] Step 5: The mixed solution obtained in step 4 was allowed to stand for 30 minutes, and then its potential value was measured. It was then dried in an oven at 85° C. for 2 hours to obtain the modified titanium dioxide papermaking filler particles.

[0158] Test Example 1

[0159] In this test example, the papermaking filler particles provided in Examples 3, 5, and Comparative Examples 1-5, as well as ordinary rutile titanium dioxide, were added as additives to paper pulp, and papermaking was performed. The resulting paper was then cut into paper samples of appropriate specifications using a cutter. The paper samples were placed in a standard testing chamber under constant temperature and humidity. After four hours, the weathering resistance was measured in a Dayongfangyi YG(B)611-III solar weathering tester. The parameters were set as follows: chamber temperature 35°C, chamber humidity 40%, BS(P)T: 50, and irradiance (Irr): 1.1. These experimental conditions accelerated the aging process of the paper samples, and the radiation exposure to the paper samples in one hour was equivalent to one week under natural conditions. The paper samples were removed every 12 hours and observed for yellowing, chalking, or surface defects such as bubbles and pitting. When the paper sample shows yellowing, powdering, etc., the weather resistance test of the paper sample is terminated, and the length of time required for the change to appear is used as the weather resistance test indicator.

[0160] The weather resistance data obtained in this test example are shown in Table 1 below.

[0161] Table 1

[0162]

[0163] As can be seen from Table 1 above, the weather resistance of paper produced using the functionalized titanium dioxide papermaking filler provided in Example 3 of the present invention as an additive is significantly improved compared to paper produced using ordinary rutile titanium dioxide and the papermaking filler particles provided in Comparative Examples 1 to 5 as additives. Furthermore, compared to the functionalized titanium dioxide papermaking filler produced using dimethyldiallylammonium chloride as a cationic reagent in Example 5, the weather resistance of paper produced using the functionalized titanium dioxide papermaking filler provided in Example 3 of the present invention as an additive is significantly improved, indicating that polydiallyldimethylammonium chloride outperforms dimethyldiallylammonium chloride when used as a cationic reagent.

[0164] Test Example 2

[0165] In this test example, the papermaking filler particles provided in Examples 1-5 and Comparative Examples 1-5, as well as ordinary rutile titanium dioxide, were added as additives to paper pulp, and papermaking was performed. The resulting paper was then cut into paper samples of appropriate specifications using a cutter. The paper samples were placed in a standard testing room under constant temperature and humidity. After four hours, the whiteness, smoothness, and opacity were measured using a ZB-B whiteness meter, a phDY-1 Buick smoothness meter, and a WSB-V intelligent whiteness tester, respectively. Herein:

[0166] Opacity R = R0 / R∞ (Eq. 1);

[0167] Formula 1): R0 is the single-layer reflection factor of the front or back side of the paper sample, %;

[0168] R∞ is the internal reflection factor of the front or back of the paper sample, %.

[0169] The whiteness, smoothness, and opacity data obtained in this test example are shown in Table 2 below.

[0170] Among them, the paper whiteness test is carried out in accordance with GB / T24999-2 110 "Maximum Limits of Brightness (Whiteness) of Paper and Paperboard";

[0171] The paper smoothness test is carried out in accordance with GB / T456-2002 Paper and board - Determination of smoothness.

[0172] The paper opacity test is carried out in accordance with GB / T 1543-2005 Paper and paperboard - Determination of opacity (paper backing) (diffuse reflectance method).

[0173] Table 2

[0174] Whiteness % Smoothness Opacity % Example 1 83 94.3 84.8 Example 2 83.4 94.2 85 Example 3 85.4 94.5 86.3 Example 4 81.2 93.9 84.6 Ordinary rutile titanium dioxide 77.3 92 82.9 Example 5 82.2 93.5 84.5 Comparative Example 1 81 92.5 82.7 Comparative Example 2 78.8 94 82.7 Comparative Example 3 79.2 93.8 83 Comparative Example 4 77.6 94.1 84.4 Comparative Example 5 81.4 93.4 84.2

[0175] As can be seen from Table 2 above, compared to paper produced using ordinary rutile titanium dioxide as an additive, the whiteness, smoothness, opacity, and other properties of paper produced using the functionalized titanium dioxide papermaking filler provided in Examples 1 to 5 of the present invention as an additive are all improved. Furthermore, compared to the other examples, the whiteness, smoothness, and opacity of paper produced using the functionalized titanium dioxide papermaking filler provided in Example 3 of the present invention as an additive are the most excellent. It can also be seen from Table 2 above that, compared to paper produced using the papermaking filler particles provided in Control Examples 1 to 5 as an additive, the whiteness, smoothness, and opacity of paper produced using the functionalized titanium dioxide papermaking filler provided in Example 3 of the present invention as an additive are all improved.

[0176] Test Example 3

[0177] This test example performs potential tests on the papermaking filler particles provided by Examples 1 to 5 and Comparative Examples 1 to 5, respectively, and specifically includes the following steps:

[0178] The modified titanium dioxide solutions obtained after standing for 30 minutes in step 5 of Examples 1 to 5 and Control Examples 1 to 5 were diluted to a nearly colorless and transparent state, and then a certain amount of 2 mmol / L sodium chloride solution was added to each solution and subjected to potential testing on a Zeta potential analyzer. The same sample was tested multiple times, and the average value was taken as the potential data of the sample.

[0179] The potential test data obtained in this test example are shown in Table 3 below. In addition, the potential analysis diagram of the modified titanium dioxide solution obtained in Example 3 of the present invention (i.e., the mixed solution obtained in step 4) and the potential analysis diagram of the modified titanium dioxide solution obtained in Example 3 after long-term standing (i.e., after the mixed solution obtained in step 4 was allowed to stand for 30 minutes) are shown in Table 3 below. Figure 2 and Figure 3 shown.

[0180] Table 3

[0181] Serial number Potential (mV) Potential after prolonged exposure (mV) Example 1 31.24 30.43 Example 2 32.42 31.28 Example 3 38.35 37.66 Example 4 44.18 47.34 Example 5 32.43 30.25 Comparative Example 1 33.56 33.25 Comparative Example 2 37.43 38.12 Comparative Example 3 37.69 37.96 Comparative Example 4 31.64 30.94 Comparative Example 5 33.54 32.36

[0182] From Table 3 above and Figure 2-Figure 3 It can be seen that in Examples 1 to 4, as the amount of cationic reagent increases, the potential of the mixed solution obtained in step 4 and the mixed solution after standing for 30 minutes gradually increases. Figure 2-Figure 3 It can be seen that by changing certain factors in the preparation process, such as the content of each additive, the amount of reactive dye, the amount of cationic reagent, temperature, etc., the most preferred embodiment of the present invention is determined to be Example 3.

[0183] Test Example 4

[0184] In this test example, the functionalized titanium dioxide papermaking filler provided in Example 3 of the present invention and the unmodified titanium dioxide, i.e., ordinary rutile titanium dioxide, are first used as additives in the production of dictionary paper. The obtained dictionary paper is then tested for whiteness, smoothness, and opacity. The whiteness, smoothness, and opacity test results obtained in this test example are shown in Table 4 below.

[0185] Among them, the paper whiteness test is carried out in accordance with GB / T24999-2 110 "Maximum Limits of Brightness (Whiteness) of Paper and Paperboard";

[0186] The paper smoothness test is carried out in accordance with GB / T456-2002 Paper and board - Determination of smoothness.

[0187] The paper opacity test is carried out in accordance with GB / T 1543-2005 Paper and paperboard - Determination of opacity (paper backing) (diffuse reflectance method).

[0188] Table 4

[0189]

[0190] It can be seen from Table 4 above that compared with the dictionary paper produced by using unmodified titanium dioxide, i.e., ordinary rutile titanium dioxide as an additive for the papermaking of dictionary paper, the dictionary paper produced by using the functionalized titanium dioxide papermaking filler provided in Example 3 of the present invention as an additive for the papermaking of dictionary paper has better properties such as whiteness, smoothness and opacity.

[0191] Test Example 5

[0192] In this test example, the functionalized titanium dioxide papermaking filler provided in Example 3 of the present invention and unmodified titanium dioxide, i.e., ordinary rutile titanium dioxide, were first used as additives in the production of coated paper. The resulting coated paper was then tested for whiteness, smoothness, glossiness, and opacity. The whiteness, smoothness, glossiness, and opacity test results obtained in this test example are shown in Table 5 below.

[0193] Among them, the paper whiteness test is carried out in accordance with GB / T24999-2 110 "Maximum Limits of Brightness (Whiteness) of Paper and Paperboard";

[0194] The paper smoothness test is carried out in accordance with GB / T456-2002 Paper and board - Determination of smoothness.

[0195] The paper opacity test is carried out in accordance with GB / T 1543-2005 Paper and paperboard - Determination of opacity (paper backing) (diffuse reflectance method).

[0196] The paper gloss test is carried out in accordance with GB / T 8941-2013 “Paper and board—Determination of specular gloss”.

[0197] Table 5

[0198]

[0199]

[0200] As can be seen from Table 5 above, compared with the coated paper produced by using unmodified titanium dioxide, i.e., ordinary rutile titanium dioxide as an additive for the production of coated paper, the coated paper produced by using the functionalized titanium dioxide papermaking filler provided in Example 3 of the present invention as an additive for the production of coated paper has better properties such as smoothness, glossiness and opacity, while the whiteness of the two is basically the same and there is no obvious difference.

[0201] Test Example 6

[0202] In this test example, the functionalized titanium dioxide papermaking filler provided in Example 3 of the present invention and unmodified titanium dioxide, i.e., ordinary rutile titanium dioxide, were first used as additives in the production of decorative paper. The retention rate and fluorescence intensity of the resulting decorative paper were then tested using conventional methods in the art. The test results are shown in Tables 6 and 7 below.

[0203] Table 6

[0204]

[0205] Table 7

[0206]

[0207] As can be seen from Tables 6 and 7 above, when the functionalized titanium dioxide papermaking filler provided in Example 3 of the present invention is used for decorative papermaking, ordinary rutile titanium dioxide has a certain positive charge after cationic surface modification. It can better combine with negatively charged pulp fibers through electrostatic attraction, enhancing the adhesion of titanium dioxide to the fibers. Its retention rate in paper is higher than that of ordinary titanium dioxide, with the retention rate increased by about 11.5%. In addition, the electrostatic attraction between the cationic titanium dioxide and the negatively charged pulp fibers causes it to be more evenly adsorbed on the fiber surface, thereby improving its dispersion uniformity in the paper. Therefore, the fluorescence intensity of the paper made using the cationic titanium dioxide is lower than that of the paper made using ordinary titanium dioxide. Therefore, the functionalized titanium dioxide papermaking filler provided in the embodiment of the present invention can meet the process control requirements for retention rate and fluorescence intensity of specialty papers such as decorative paper.

[0208] Furthermore, the functionalized titanium dioxide papermaking filler provided in the embodiments of the present invention can be used in decorative paper to improve its opacity, gloss, and strength, making the resulting decorative paper thin and smooth, impervious to penetration during printing, and exhibiting excellent coverage and surface smoothness. Compared to conventional rutile titanium dioxide, decorative paper prepared using the functionalized titanium dioxide papermaking filler as an additive exhibits a finer texture and richer color, making it suitable for a variety of applications, including furniture, flooring, wallpaper, and raw materials.

[0209] Compared with ordinary colored decorative paper dyed in the pulp with inorganic dyes or dyed on the surface of the printing press, the colored decorative paper with the functionalized titanium dioxide papermaking filler provided by the embodiment of the present invention has strong covering power, uniform color, and can improve the low basis weight. At the same time, the loss of pigment is less, and the difficulty of wastewater treatment can be reduced, which is more conducive to environmentally friendly production.

[0210] From the experimental data obtained in Test Examples 1 to 6, it can be seen that by comparing the quality of various papers such as copperplate paper, dictionary paper, decorative paper, etc. obtained by using ordinary rutile titanium dioxide or the modified titanium dioxide papermaking filler particles provided in the control example as an additive with the quality of various papers such as copperplate paper, dictionary paper, decorative paper, etc. obtained by using the functionalized titanium dioxide papermaking filler provided in the embodiment of the present invention as an additive, the results show that the functionalized titanium dioxide papermaking filler provided in the embodiment of the present invention can be used as an additive for the production of high-grade paper and other papers, and has a wide range of applications and obvious effects.

[0211] In summary, the embodiment of the present invention first uses a silicon coating / silicon film formed by sodium silicate to coat the rutile titanium dioxide and silicon nitride as a whole, then dyes them with reactive dyes, and finally performs cationization treatment and coating modification on the rutile titanium dioxide and silicon nitride coated with the silicon coating as a whole, so that the functionalized titanium dioxide papermaking filler finally obtained has better weather resistance and more flexible paper coloring properties. At the same time, the functionalized titanium dioxide papermaking filler is used to make various papers, which can also effectively reduce the fluorescence intensity of the paper and meet the special functionalization requirements of the filler. It can be seen that the functionalized titanium dioxide papermaking filler has a wide range of applications and good economic benefits. In addition, the preparation method of the functionalized titanium dioxide papermaking filler provided in the embodiment of the present invention is simple to operate and highly practical.

[0212] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, substitutions of equivalent components, or equivalent changes and modifications made within the scope of patent protection, should still fall within the scope of this patent. Furthermore, the technical features of this invention may be freely combined with one another, with other technical inventions, and with other technical inventions.

Claims

1. A functionalized titanium dioxide papermaking filler, characterized in that: The raw material composition of the functionalized titanium dioxide papermaking filler comprises, by weight: 45-55 parts by weight of rutile titanium dioxide, 3-6 parts by weight of reactive dye, 2-8 parts by weight of cationic agent, 1-2 parts by weight of potassium aluminum sulfate dodecahydrate, 4-7 parts by weight of sodium silicate, 3-4 parts by weight of silicon nitride, 1-2 parts by weight of silane coupling agent, 2-5 parts by weight of dyeing auxiliary, 2-5 parts by weight of dispersant, 2-5 parts by weight of defoaming agent, 20-30 parts by weight of 15-25% ammonia aqueous solution, and 135-165 parts by weight of deionized water; The functionalized titanium dioxide papermaking filler is prepared by a preparation method comprising the following steps: Step 1: adding rutile titanium dioxide to deionized water, and preparing a titanium dioxide slurry under heating and stirring conditions; then adding sodium silicate and silicon nitride to the titanium dioxide slurry and continuing to heat and stir, so that the sodium silicate performs silicon coating treatment on the rutile titanium dioxide and silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride; Step 2: Adding a reactive dye and a dyeing auxiliary into deionized water, and preparing a dyeing solution under heating and stirring conditions; adding the silicon-coated rutile titanium dioxide and silicon nitride into the dyeing solution and continuously heating and stirring; then adding potassium aluminum sulfate dodecahydrate and continuing to stir to fully dye the rutile titanium dioxide; Step 3: After the solution obtained in step 2 is allowed to settle, the upper dye solution is poured off, and then the solution is repeatedly rinsed with deionized water for several times and filtered. The titanium dioxide paste obtained after filtration is then added to deionized water to prepare a titanium dioxide paste aqueous solution, and then ammonia water with a mass concentration of 15-25% is added under stirring to adjust the pH value of the system; Step 4: Add the cationic reagent, dispersant, and silane coupling agent to the solution obtained in step 3 in sequence, mix them evenly under heating and stirring conditions, then add the defoaming agent and continue stirring to mix them evenly; Step 5: Dry the mixed solution obtained in step 4 to obtain the functionalized titanium dioxide papermaking filler.

2. The functionalized titanium dioxide papermaking filler according to claim 1, characterized in that: The reactive dye comprises one or a combination of reactive bright yellow K-6G, reactive red 3BF, reactive golden yellow 3RS and reactive turquoise blue K-GL.

3. The functionalized titanium dioxide papermaking filler according to claim 1 or 2, characterized in that: The cationic agent includes one or a combination of polydiallyldimethylammonium chloride, dimethyldiallylammonium chloride and cationic polyacrylamide.

4. The functionalized titanium dioxide papermaking filler according to claim 1 or 2, characterized in that: The silane coupling agent includes one or a combination of γ-methacryloxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane.

5. The functionalized titanium dioxide papermaking filler according to claim 1 or 2, characterized in that: The dispersant includes one or a combination of polyethylene oxide and polycarboxylates.

6. The functionalized titanium dioxide papermaking filler according to claim 1 or 2, characterized in that: The defoaming agent includes one or a combination of polydimethylsiloxane and emulsified silicone oil.

7. The functionalized titanium dioxide papermaking filler according to claim 1 or 2, characterized in that: The dyeing auxiliary agent includes one or a combination of glauber salt, sodium chloride and acetic acid.

8. The method for preparing the functionalized titanium dioxide papermaking filler according to any one of claims 1 to 7, characterized in that: The preparation method comprises: Step 1: adding rutile titanium dioxide to deionized water, and preparing a titanium dioxide slurry under heating and stirring conditions; then adding sodium silicate and silicon nitride to the titanium dioxide slurry and continuing to heat and stir, so that the sodium silicate performs silicon coating treatment on the rutile titanium dioxide and silicon nitride as a whole, thereby obtaining silicon-coated rutile titanium dioxide and silicon nitride; Step 2: Adding a reactive dye and a dyeing auxiliary into deionized water, and preparing a dyeing solution under heating and stirring conditions; adding the silicon-coated rutile titanium dioxide and silicon nitride into the dyeing solution and continuously heating and stirring; then adding potassium aluminum sulfate dodecahydrate and continuing to stir to fully dye the rutile titanium dioxide; Step 3: After the solution obtained in step 2 is allowed to settle, the upper dye solution is poured off, and then the solution is repeatedly rinsed with deionized water for several times and filtered. The titanium dioxide paste obtained after filtration is then added to deionized water to prepare a titanium dioxide paste aqueous solution, and then ammonia water with a mass concentration of 15-25% is added under stirring to adjust the pH value of the system; Step 4: Add the cationic reagent, dispersant, and silane coupling agent to the solution obtained in step 3 in sequence, mix them evenly under heating and stirring conditions, then add the defoaming agent and continue stirring to mix them evenly; Step 5: Dry the mixed solution obtained in step 4 to obtain the functionalized titanium dioxide papermaking filler.

9. The preparation method according to claim 8, characterized in that In step 1: the heating and stirring conditions are: temperature is 80 o C, the speed is 500-600 rpm, and the stirring time is 1-1.5h; The conditions for continuous heating and stirring are: temperature 80 o C, speed 500 rpm, stirring time 1 h.

10. The preparation method according to claim 8 or 9, characterized in that: In step 2: the heating and stirring conditions are: temperature 70 o C, speed is 300-500 rpm, stirring time is 1-1.5h; The conditions for continuous heating and stirring are: temperature 70 o C, speed 300 rpm, stirring time 1 h; The stirring time is continued for 0.5 h.

11. The preparation method according to claim 8 or 9, characterized in that: In step 3: the pH value of the system is adjusted to 8-9.

12. The preparation method according to claim 8 or 9, characterized in that: In step 4: the heating and stirring conditions are: temperature 60 o C, speed 300 rpm, stirring time 1 h; The stirring conditions are as follows: a rotation speed of 300 rpm and a stirring time of 2 h.

13. The preparation method according to claim 8 or 9, characterized in that: In step 5: the drying is 85 o C and dried for 2 h.

14. Use of the functionalized titanium dioxide papermaking filler according to any one of claims 1 to 7 in the production of special paper.

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