Siliconized microcrystalline cellulose with friction cleaning performance and preparation method thereof

Abstract

The present invention provides a silicified microcrystalline cellulose with friction cleaning performance and a preparation method thereof, comprising the following steps: step (1), preparation of water glass; step (2), preparation of cellulose; step (3), preparation of microcrystalline cellulose; step (4), preparation of silicified microcrystalline cellulose powder. The present invention uses specially prepared active silicic acid to react with microcrystalline cellulose wet material. The high-quality active silicic acid of the present invention has higher activity and reaction efficiency, can be more evenly attached to the cellulose surface when reacting with microcrystalline cellulose, forming a stable silicified layer, the silicification reaction is complete and evenly distributed on the cellulose surface, and finally the particle size distribution of the silicified microcrystalline cellulose is even, thereby improving the bulk density and particle size uniformity.

Description

Technical Field

[0001] The invention belongs to the technical field of silicified microcrystalline cellulose, and particularly relates to silicified microcrystalline cellulose with friction cleaning performance and a preparation method thereof. Background Art

[0002] Toothpaste abrasives are solid components in toothpaste that can work together with a toothbrush to remove dental plaque on the surface of teeth through mechanical friction, and reduce foreign substances such as tooth stains, plaque, and tartar. Abrasives are one of the main raw materials of toothpaste, generally accounting for 20%-50% of the formula.

[0003] Common toothpaste abrasives include natural calcium carbonate, calcium hydrogen phosphate dihydrate, precipitated silica, aluminum hydroxide, light calcium carbonate, anhydrous calcium hydrogen phosphate, etc., among which natural calcium carbonate, calcium hydrogen phosphate dihydrate and precipitated silica are the three most important abrasives. The conditions for being used as a toothpaste abrasive are: the abrasive should have appropriate hardness and friction value, uniform particle size, white appearance, no odor, comfortable taste, safe and non-toxic, low solubility and stable chemical properties, and no chemical reaction with other components in toothpaste.

[0004] The application of silicified microcrystalline cellulose in friction cleaning is mainly due to its unique physical and chemical properties: microcrystalline cellulose itself is a non-toxic, odorless porous powder. Microcrystalline cellulose (MCC) is a porous, amorphous powder obtained by special processing of plant cellulose, usually presenting a white or nearly white fine crystal structure. This material has a wide range of applications in many fields and has good hygroscopicity and adsorption, which allows it to absorb and remove dirt and grease, just like an efficient "cleaning sponge". When used as a detergent in cleaning products, its fine particles can penetrate into the tiny gaps on the surface of the object and remove the stains through physical friction. Siliconization refers to the introduction of silane groups or a layer of silicon dioxide on its surface through chemical reactions, so that the treated silicified microcrystalline cellulose can enhance its hydrophobicity, wear resistance and dispersibility. In the detergent formula, siliconization helps the microcrystalline cellulose particles to be better dispersed in the cleaning medium, while enhancing its adsorption and repulsion capabilities for oily stains and improving cleaning efficiency.

[0005] In some cleaning products, silicified microcrystalline cellulose can also provide moderate abrasive force and be used as a mild polishing agent to help remove minor surface scratches or aging layers without damaging the substrate. It is suitable for cleaning precision parts or sensitive surfaces. Due to its excellent stability, silicified microcrystalline cellulose can maintain its shape integrity during the cleaning process and will not excessively wear the cleaned object. At the same time, it can be easily rinsed off after cleaning without leaving any residue. Therefore, the application of silicified microcrystalline cellulose in the field of friction cleaning is mainly through its own adsorption, dispersibility and appropriate mechanical force, in conjunction with other ingredients of cleaning products to complete the cleaning of the surface of the object.

[0006] In the application of silicified microcrystalline cellulose in the field of friction cleaning, its bulk density and particle size uniformity are very critical characteristics, which directly affect the cleaning effect and the overall performance of the product: high bulk density means that the weight of silicified microcrystalline cellulose per unit volume is large, which may be beneficial to increase the content of active ingredients in cleaning products in detergent formulations, thereby enhancing cleaning effectiveness. Products with high bulk density are more likely to remain tightly packed under pressure, and can provide better contact force and scraping force during wiping or brushing, which is beneficial for removing stubborn stains. If the bulk density is too low, it may cause the detergent to require more in actual use to achieve the expected cleaning effect, and may also affect the stability of the detergent mixture. Silicicated microcrystalline cellulose with uniform particle size can be more evenly distributed in the cleaning medium during the cleaning process, ensuring that particles of various sizes can produce effective friction and adsorption effects on dirt gaps of different sizes, thereby improving the comprehensiveness and depth of cleaning. If the particle size distribution is uneven, large particles may cause excessive local mechanical friction, resulting in damage to the surface of the cleaning object; while small particles may not be able to effectively remove stains in larger gaps. Therefore, the ideal particle size distribution can be adapted to different cleaning requirements, neither excessive abrasion nor incomplete cleaning.

[0007] In summary, in friction cleaning applications, the appropriate bulk density of silicified microcrystalline cellulose can optimize cleaning power and cost-effectiveness, while uniform particle size can ensure the balance and safety of the cleaning effect. For specific application scenarios, it is crucial to select silicified microcrystalline cellulose with appropriate bulk density and particle size distribution. However, the bulk density and particle size uniformity of silicified microcrystalline cellulose on the market are not ideal. Summary of the invention

[0008] The purpose of the present invention is to provide a silicified microcrystalline cellulose with friction cleaning performance and a preparation method thereof.

[0009] In order to achieve the above object, the present invention provides the following technical solutions:

[0010] A method for preparing silicified microcrystalline cellulose with friction cleaning performance comprises the following steps:

[0011] Step (1), preparation of water glass: reacting rice husk ash in a sodium hydroxide solution having a concentration of 4-7wt%, with the mass ratio of rice husk ash to sodium hydroxide solution being 1:5-8 at a temperature of 85-95°C, and then filtering, decolorizing and washing to obtain a water glass solution;

[0012] Step (2), preparation of cellulose: adding 1 part by weight of crude cellulose to 8-9 parts by weight of a mixed solution containing 4-6wt% sodium hydroxide solution and 2-4wt% hydrogen peroxide solution, heating and stirring at 74-76°C for 10-12h, cooling to room temperature, filtering, washing, and drying to obtain white fine cellulose.

[0013] Step (3), preparation of microcrystalline cellulose: 1 part by weight of white fine cellulose and 12-15 parts by weight of distilled water are mixed, sulfuric acid solution is added dropwise to adjust the pH to neutral, the mixture is stirred at 72-73° C. for 2-3 hours, and cooled to room temperature to obtain a mixed solution, 3-5 times the amount of cold distilled water as the mixed solution is added, the mixture is allowed to stand, filtered, the solid is washed with distilled water until it is neutral, dried, and sieved to obtain white microcrystalline cellulose;

[0014] Step (4), preparation of silicified microcrystalline cellulose powder; the white microcrystalline cellulose prepared in step (3) is dispersed and mixed with water, and the water glass solution and sulfuric acid solution prepared in step (1) are added at the same time under stirring, the temperature is 60-95°C, wherein the volume ratio of the microcrystalline cellulose mixed liquid, the water glass solution and the sulfuric acid solution is 5-8:9-12:1, and the pH is controlled to be 6.5-8.5. After stirring evenly, the reaction material is transferred to a pressure-resistant reaction tank, and the reaction is continued for 3-5 hours under the conditions of a temperature of 140-160°C and a vapor pressure of 0.4-0.7MPa. After the reaction, the reaction precipitate is filtered and repeatedly washed to obtain a silicified microcrystalline cellulose wet material, and the silicified microcrystalline cellulose wet material is dried at a temperature of 110-120°C to a water content of ≤10%. After cooling, the silicified microcrystalline cellulose wet material is crushed by gas to a granular powder with a particle size of 10-20μm to obtain a white silicified microcrystalline cellulose powder.

[0015] The invention also provides silicified microcrystalline cellulose prepared by the preparation method.

[0016] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0017] 1. The microcrystalline cellulose of the present invention can be derived from plant bodies such as bagasse, wood powder, corn cobs, coconut shells, straw, etc. Microcrystalline cellulose is a green, environmentally friendly and renewable resource, but it cannot be used as an abrasive. Conventional silicified microcrystalline cellulose cannot be used as a toothpaste abrasive due to the process and low degree of silicification (silicon content is less than 5%). The silicified microcrystalline cellulose prepared in this article uses a new process and improves the degree of silicification (silicon content) at the same time, which solves the problem of using green and environmentally friendly cellulose and green and environmentally friendly water glass as raw materials to prepare a toothpaste abrasive that can be used in the toothpaste industry.

[0018] 2. In the friction cleaning application, the silicified microcrystalline cellulose of the present invention has an appropriate bulk density that can optimize the cleaning power and cost-effectiveness, while the uniform particle size can ensure the balance and safety of the cleaning effect, and enhance the adsorption capacity and decontamination efficiency of grease, stains, etc. Products with uniform particle size can provide consistent friction during the cleaning process, better enter tiny gaps and grooves, and effectively remove various hard-to-reach dirt. The appropriate bulk density enables the silicified microcrystalline cellulose to provide sufficient mechanical cleaning power in the detergent formula without excessively scratching the surface of the cleaning object, thereby protecting the cleaned objects from damage, and is particularly suitable for cleaning high-value items such as precision instruments, optical lenses, and electronic equipment. The silicified microcrystalline cellulose with an appropriate bulk density and uniform particle size has a higher value in the market because such products have the following advantages: the silicified microcrystalline cellulose with an appropriate bulk density and uniform particle size has a strong market demand due to its excellent performance and wide range of applications, and the price is relatively high, and the market value is also increased accordingly. With the continuous improvement of product quality requirements and technological progress in various industries, the development and market expansion prospects of this type of product are very promising. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Example 1

[0021] This embodiment provides a method for preparing silicified microcrystalline cellulose with friction cleaning performance, comprising the following steps:

[0022] Step (1), preparation of water glass: rice husk ash is reacted in a sodium hydroxide solution with a concentration of 6wt%, with the mass ratio of rice husk ash to sodium hydroxide solution being 1:6, at a temperature of 90°C, and then filtered, decolorized and washed to obtain a water glass solution;

[0023] Step (2), preparation of cellulose: 1 part by weight of crude cellulose is added to 8.5 parts by weight of a mixed solution containing 5 wt% sodium hydroxide and 3 wt% hydrogen peroxide solution, heated and stirred at 75° C. for 11 hours, cooled to room temperature, filtered, washed, and dried to obtain white fine cellulose.

[0024] Step (3), preparation of microcrystalline cellulose: 1 part by weight of white fine cellulose and 13 parts by weight of distilled water are mixed, sulfuric acid solution is added dropwise to adjust the pH to neutral, the mixture is stirred at 72° C. for 2.5 hours, cooled to room temperature to obtain a mixed solution, 4 times the amount of cold distilled water as the mixed solution is added, the mixture is allowed to stand, filtered, the solid is washed with distilled water until it is neutral, dried, and sieved to obtain white microcrystalline cellulose;

[0025] Step (4), preparation of silicified microcrystalline cellulose powder; the white microcrystalline cellulose prepared in step (3) is dispersed and mixed with water, and under stirring conditions, the water glass solution prepared in step (1) and a certain mass fraction of sulfuric acid solution are added at the same time, the temperature is 80°C, wherein the volume ratio of the microcrystalline cellulose mixed liquid, the water glass solution and the sulfuric acid solution is 7:10:1, and the pH is controlled to 7. After stirring evenly, all the reaction materials are transferred to a pressure-resistant reaction tank, and the reaction is continued for 3 hours under the conditions of a temperature of 150°C and a vapor pressure of 0.5 MPa. After the reaction, the reaction precipitate is filtered and repeatedly washed to obtain a silicified microcrystalline cellulose wet material, and the silicified microcrystalline cellulose wet material is dried at a temperature of 110°C to a water content of ≤10%. After cooling, the silicified microcrystalline cellulose wet material is crushed by gas to a granular powder with a particle size of 10-20 μm to obtain a white silicified microcrystalline cellulose powder.

[0026] Example 2

[0027] This embodiment provides a method for preparing silicified microcrystalline cellulose with friction cleaning performance, comprising the following steps:

[0028] Step (1), preparation of water glass: rice husk ash is reacted in a sodium hydroxide solution having a concentration of 4wt%, with the mass ratio of rice husk ash to sodium hydroxide solution being 1:5, at a temperature of 85°C, and then filtered, decolorized and washed to obtain a water glass solution;

[0029] Step (2), preparation of cellulose: adding 1 part by weight of crude cellulose to 8 parts by weight of a mixed solution containing 4 wt% sodium hydroxide solution and 2 wt% hydrogen peroxide solution, heating and stirring at 74° C. for 10 h, cooling to room temperature, filtering, washing, and drying to obtain white fine cellulose.

[0030] Step (3), preparation of microcrystalline cellulose: 1 part by weight of white fine cellulose and 12 parts by weight of distilled water are mixed, sulfuric acid solution is added dropwise to adjust the pH to neutral, the mixture is stirred at 72° C. for 2 hours, cooled to room temperature to obtain a mixed solution, 3 times the amount of cold distilled water as the mixed solution is added, the mixture is allowed to stand, filtered, the solid is washed with distilled water until it is neutral, dried, and sieved to obtain white microcrystalline cellulose;

[0031] Step (4), preparation of silicified microcrystalline cellulose powder; the white microcrystalline cellulose prepared in step (3) is dispersed and mixed with water, and under stirring conditions, the water glass solution prepared in step (1) and a certain mass fraction of sulfuric acid solution are added at the same time, the temperature is 60°C, wherein the volume ratio of the microcrystalline cellulose mixed liquid, the water glass solution and the sulfuric acid solution is 5:9:1, and the pH is controlled to be 6.5. After stirring evenly, all the reaction materials are transferred to a pressure-resistant reaction tank, and the reaction is continued for 3 hours under the conditions of a temperature of 140°C and a vapor pressure of 0.4 MPa. After the reaction, the reaction precipitate is filtered and repeatedly washed to obtain a silicified microcrystalline cellulose wet material, and the silicified microcrystalline cellulose wet material is dried at a temperature of 110°C to a water content of ≤10%. After cooling, the silicified microcrystalline cellulose wet material is crushed by gas to a granular powder with a particle size of 10-20 μm to obtain a white silicified microcrystalline cellulose powder.

[0032] Example 3

[0033] This embodiment provides a method for preparing silicified microcrystalline cellulose with friction cleaning performance, comprising the following steps:

[0034] Step (1), preparation of water glass; reacting rice husk ash in a 7wt% sodium hydroxide solution, with the mass ratio of rice husk ash to sodium hydroxide solution being 1:8, at a temperature of 95°C, and then filtering, decolorizing and washing to obtain a water glass solution;

[0035] Step (2), preparation of cellulose: add 1 part by weight of crude cellulose to 9 parts by weight of a mixed solution containing 6 wt% sodium hydroxide solution and 4 wt% hydrogen peroxide solution, heat and stir at 76°C for 12 hours, cool to room temperature, filter, wash and dry to obtain white fine cellulose.

[0036] Step (3), preparation of microcrystalline cellulose: 1 part by weight of white fine cellulose and 15 parts by weight of distilled water are mixed, sulfuric acid solution is added dropwise to adjust the pH to neutral, the mixture is stirred at 73° C. for 3 hours, and cooled to room temperature to obtain a mixed solution, 5 times the amount of cold distilled water as the mixed solution is added, the mixture is allowed to stand, filtered, the solid is washed with distilled water until it is neutral, dried, and sieved to obtain white microcrystalline cellulose;

[0037] Step (4), preparation of silicified microcrystalline cellulose powder; the white microcrystalline cellulose prepared in step (3) is dispersed and mixed with water, and under stirring conditions, the water glass solution prepared in step (1) and a certain mass fraction of sulfuric acid solution are added at the same time, the temperature is 95°C, wherein the volume ratio of the microcrystalline cellulose mixed liquid, the water glass solution and the sulfuric acid solution is 8:12:1, and the pH is controlled to be 8.5. After stirring evenly, all the reaction materials are transferred to a pressure-resistant reaction tank, and the reaction is continued for 5 hours under the conditions of a temperature of 160°C and a vapor pressure of 0.7 MPa. After the reaction, the reaction precipitate is filtered and repeatedly washed to obtain a silicified microcrystalline cellulose wet material, and the silicified microcrystalline cellulose wet material is dried at a temperature of 120°C to a water content of ≤10%. After cooling, the silicified microcrystalline cellulose wet material is crushed by gas to a granular powder with a particle size of 10-20 μm to obtain a white silicified microcrystalline cellulose powder.

[0038] Example 4

[0039] A method for preparing silicified microcrystalline cellulose with friction cleaning performance comprises the following steps:

[0040] Step (1), preparation of water glass; reacting rice husk ash in a sodium hydroxide solution having a concentration of 4wt%, with the mass ratio of rice husk ash to sodium hydroxide solution being 1:8 at a temperature of 85°C, and then filtering, decolorizing and washing to obtain a water glass solution;

[0041] Step (2), preparation of cellulose: 1 part by weight of crude cellulose is added to 9 parts by weight of a mixed solution containing 4 wt% sodium hydroxide solution and 4 wt% hydrogen peroxide solution, heated and stirred at 74° C. for 12 h, cooled to room temperature, filtered, washed, and dried to obtain white fine cellulose.

[0042] Step (3), preparation of microcrystalline cellulose: 1 part by weight of white fine cellulose and 12 parts by weight of distilled water are mixed, sulfuric acid solution is added dropwise to adjust the pH to neutral, the mixture is stirred at 73° C. for 2 hours, cooled to room temperature to obtain a mixed solution, 5 times the amount of cold distilled water as the mixed solution is added, the mixture is allowed to stand, filtered, the solid is washed with distilled water until it is neutral, dried, and sieved to obtain white microcrystalline cellulose;

[0043] Step (4), preparation of silicified microcrystalline cellulose powder; the white microcrystalline cellulose prepared in step (3) is dispersed and mixed with water, and under stirring conditions, the water glass solution prepared in step (1) and a certain mass fraction of sulfuric acid solution are added at the same time, the temperature is 60°C, wherein the volume ratio of the microcrystalline cellulose mixed liquid, the water glass solution and the sulfuric acid solution is 8:9:1, and the pH is controlled to be 8.5. After stirring evenly, all the reaction materials are transferred to a pressure-resistant reaction tank, and the reaction is continued for 3 hours under the conditions of a temperature of 140°C and a vapor pressure of 0.7 MPa. After the reaction, the reaction precipitate is filtered and repeatedly washed to obtain a silicified microcrystalline cellulose wet material, and the silicified microcrystalline cellulose wet material is dried at a temperature of 120°C to a water content of ≤10%. After cooling, the silicified microcrystalline cellulose wet material is crushed by gas to a granular powder with a particle size of 10-20 μm to obtain a white silicified microcrystalline cellulose powder.

[0044] Example 5

[0045] A method for preparing silicified microcrystalline cellulose with friction cleaning performance comprises the following steps:

[0046] Step (1), preparation of water glass: rice husk ash is reacted in a sodium hydroxide solution having a concentration of 7wt%, with the mass ratio of rice husk ash to sodium hydroxide solution being 1:5 at a temperature of 95°C, and then filtered, decolorized and washed to obtain a water glass solution;

[0047] Step (2), preparation of cellulose: add 1 part by weight of crude cellulose to 8 parts by weight of a mixed solution containing 6 wt% sodium hydroxide solution and 2 wt% hydrogen peroxide solution, heat and stir at 76°C for 10 hours, cool to room temperature, filter, wash and dry to obtain white fine cellulose.

[0048] Step (3), preparation of microcrystalline cellulose: 1 part by weight of white fine cellulose and 15 parts by weight of distilled water are mixed, sulfuric acid solution is added dropwise to adjust the pH to neutral, the mixture is stirred at 72° C. for 3 hours, and cooled to room temperature to obtain a mixed solution, 3 times the amount of cold distilled water as the mixed solution is added, the mixture is allowed to stand, filtered, the solid is washed with distilled water until it is neutral, dried, and sieved to obtain white microcrystalline cellulose;

[0049] Step (4), preparation of silicified microcrystalline cellulose powder; the white microcrystalline cellulose prepared in step (3) is dispersed and mixed with water, and under stirring conditions, the water glass solution prepared in step (1) and a certain mass fraction of sulfuric acid solution are added at the same time, the temperature is 95°C, wherein the volume ratio of the microcrystalline cellulose mixed liquid, the water glass solution and the sulfuric acid solution is 5:12:1, and the pH is controlled to be 6.5. After stirring evenly, all the reaction materials are transferred to a pressure-resistant reaction tank, and the reaction is continued for 5 hours under the conditions of a temperature of 160°C and a vapor pressure of 0.4 MPa. After the reaction, the reaction precipitate is filtered and repeatedly washed to obtain a silicified microcrystalline cellulose wet material, and the silicified microcrystalline cellulose wet material is dried at a temperature of 110°C to a water content of ≤10%. After cooling, the silicified microcrystalline cellulose wet material is crushed by gas to a granular powder with a particle size of 10-20 μm to obtain a white silicified microcrystalline cellulose powder.

[0050] Comparative Example 1

[0051] The difference between this comparative example and Example 1 is: preparation of water glass; rice husk ash is reacted in a sodium hydroxide solution with a concentration of 2wt%, with a mass ratio of rice husk ash to sodium hydroxide solution of 1:10 at a temperature of 80°C, and then filtered, decolorized and washed to obtain a water glass solution.

[0052] Comparative Example 2

[0053] The difference between this comparative example and Example 1 is: preparation of cellulose; 1 part by weight of crude cellulose is added to 7 parts by weight of a mixed solution containing 3wt% sodium hydroxide solution and 1.5wt% hydrogen peroxide solution, heated and stirred at 70°C for 8h, cooled to room temperature, filtered, washed, and dried to obtain white fine cellulose.

[0054] Comparative Example 3

[0055] The difference between this comparative example and Example 1 is that the volume ratio of the microcrystalline cellulose mixed liquid, the water glass solution and the sulfuric acid solution is 3:15:1.

[0056] Comparative Example 4

[0057] The difference between this comparative example and Example 1 is that the reaction materials are all transferred to a pressure-resistant reaction tank, and the reaction is continued for 7 hours at a temperature of 130° C. and a vapor pressure of 0.3 MPa.

[0058] Performance Testing

[0059] Main technical indicators of silicified microcrystalline cellulose powder:

[0060] (1) Technical indicators such as whiteness (WG) and pH value are tested in accordance with the standard QB / T2346-2015 "Silicon Dioxide for Toothpaste in Oral Care Products";

[0061] (2) The friction cleaning performance of silicified microcrystalline cellulose powder was evaluated using the copper loss value.

[0062] Method for determining copper loss value: Use a hard particle measuring instrument, fix a wool round pad on the friction head of the instrument, take the copper sheet to be tested for wear and weigh its mass as M1, put the copper sheet to be tested for wear in the test slot, add the dispersed silicified microcrystalline cellulose powder dispersion (the mass ratio of silicified microcrystalline cellulose powder to dispersion is 20:100), and then start the instrument to perform 10,000 wear tests on the copper sheet. After the test, take out the copper sheet, clean it, dry it and weigh it, and measure the mass of the copper sheet as M2. The copper loss value of the silicified microcrystalline cellulose powder is M (mg), M=M1-M2; theoretically, the larger M is, the greater the wear of the powder on the copper sheet, indicating that its friction cleaning performance is better.

[0063] Table 1 Test results

[0064]

[0065] The key performance indicators of the silicified microcrystalline cellulose obtained by the present invention are as follows: whiteness (WG) ≥ 95%, pH value (5% suspension) 7.0-9.5, copper loss value (friction cleaning performance) ≥ 2.0 mg, high silicification degree, silicon content ≥ 15%, and these performance indicators meet the use requirements of toothpaste abrasives, and can be used as toothpaste abrasives.

[0066] As a powder material, the bulk density and particle size uniformity of silicified microcrystalline cellulose have an important influence on its fluidity and processing performance. The friction cleaning performance test can evaluate the characteristics of the powder by observing the effect of the material contacting and wearing another surface (such as a copper surface). The copper loss value is an indicator to measure the friction and wear performance of the material, which reflects the degree of wear caused by the material to another surface (such as copper) during the friction process. Therefore, the copper loss value can reflect the bulk density and particle size uniformity of silicified microcrystalline cellulose powder to a certain extent:

[0067] (1) Bulk density: Bulk density refers to the mass of powder per unit volume. If the bulk density of SMCC is higher, it means that there are more particles per unit volume and the contact between particles is closer. This may lead to higher friction and thus higher copper loss. Conversely, powders with lower bulk density may have fewer particles in contact, resulting in lower copper loss.

[0068] (2) Particle size uniformity: Powders with good particle size uniformity have small differences in particle size and can be more evenly distributed and contact the friction surface. If the particle size distribution of the powder is uneven, large particles may cause greater wear during the friction process, resulting in higher copper loss values; while powders with uniform particle size distribution have relatively less wear and correspondingly lower copper loss values.

[0069] The present invention can understand the bulk density and particle size uniformity of the silicified microcrystalline cellulose powder by measuring the copper consumption value. A high copper consumption value means that the bulk density and particle size uniformity of the powder are better. The new silicified microcrystalline cellulose abrasive prepared by the method enriches the raw materials of toothpaste abrasives, which is beneficial to promote the development of the toothpaste industry; it also promotes the green, environmentally friendly, low-carbon and sustainable development of the toothpaste industry, and has important practical significance for promoting the technological progress of the toothpaste industry.

[0070] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing silicified microcrystalline cellulose with friction cleaning performance, characterized in that: The following steps are involved: Step (1), preparation of water glass: reacting rice husk ash in a sodium hydroxide solution having a concentration of 4-7wt% at a temperature of 85-95°C, and then filtering, decolorizing and washing to obtain a water glass solution; Step (2), preparation of cellulose: adding 1 part by weight of crude cellulose to 8-9 parts by weight of a mixed solution containing a sodium hydroxide solution and a hydrogen peroxide solution, heating and stirring at 74-76° C. for 10-12 hours, cooling to room temperature, filtering, washing, and drying to obtain white fine cellulose; Step (3), preparation of microcrystalline cellulose: 1 part by weight of white fine cellulose and 12 to 15 parts by weight of distilled water are mixed, sulfuric acid solution is added dropwise to adjust the pH to neutral, the mixture is stirred for reaction, cooled to room temperature to obtain a mixed solution, 3 to 5 times the amount of cold distilled water as the mixed solution is added, the mixture is allowed to stand, filtered, the solid is washed with distilled water until it is neutral, dried, and sieved to obtain white microcrystalline cellulose; Step (4), preparation of silicified microcrystalline cellulose powder; the white microcrystalline cellulose prepared in step (3) is dispersed and mixed with water, and under stirring conditions, the water glass solution prepared in step (1) and a certain mass fraction of sulfuric acid solution are added at the same time, the temperature is 60-95°C, and the pH is controlled at 6.5-8.

5. After stirring evenly, all the reaction materials are transferred to a pressure-resistant reaction tank, reacted in the pressure-resistant reaction tank, cooled to room temperature after the reaction, the reaction precipitate is filtered, and repeatedly washed to obtain a silicified microcrystalline cellulose wet material, the silicified microcrystalline cellulose wet material is dried at a temperature of 110-120°C, and after cooling, it is crushed by gas into granular powder with a particle size of 10-20 μm to obtain white silicified microcrystalline cellulose powder; In step (1), the mass ratio of rice husk ash to sodium hydroxide solution is 1:5-8; The concentration of the sodium hydroxide solution in step (2) is 4-6wt%; The concentration of the hydrogen peroxide solution in step (2) is 2-4%; In step (3), the reaction is stirred at 72-73° C. for 2-3 hours; In step (4), the volume ratio of the microcrystalline cellulose mixed liquid, the water glass solution and the sulfuric acid solution is 5-8:9-12:1; The reaction conditions of the pressure-resistant reactor are: continuing the reaction for 3-5 hours at a temperature of 140-160° C. and a vapor pressure of 0.4-0.7 MPa.

2. The method for preparing silicified microcrystalline cellulose with friction cleaning performance according to claim 1, characterized in that: Dry to a moisture content of ≤10%.

3. Silicified microcrystalline cellulose obtained by the preparation method according to any one of claims 1 to 2.

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