Ultrafine, high-performance microcrystalline cellulose products and their preparation methods

Abstract

The present invention provides an ultrafine, high-performance microcrystalline cellulose product and a method for preparing the same. Specifically, the microcrystalline cellulose product has an average particle size D50 of 1 to 25 μm and a loose density of 0.50 to 0.80 g / ml. This product is produced by subjecting ordinary microcrystalline cellulose to the action of a high-shear machine using a high-shear device. The microcrystalline cellulose product of the present invention has properties such as small particle size, high density, a unique spherical or quasi-spherical particle shape, good fluidity, strong compressibility, good taste, and fine texture, and can be used in a wide range of fields, including food, pharmaceuticals, and the chemical industry.

Description

Detailed Description of the Invention

[0001] [Technical Field] The present invention relates to the field of microcrystalline cellulose, and in particular to an ultrafine, high performance microcrystalline cellulose product and a method for preparing the same.

[0002] [Background technology] Microcrystalline cellulose is a free-flowing, fine powder obtained by hydrolyzing natural cellulose with dilute acid to the leveling-off degree of polymerization (LODP). It is white or near-white in color, tasteless, and odorless. The LODP is typically between 100 and 350. It is insoluble in water, dilute acids, organic solvents, and grease. It partially dissolves and swells in dilute aqueous alkaline solutions. Microcrystalline cellulose maintains its properties even under conditions of high temperature, high humidity, and strong light exposure, making it widely used in pharmaceuticals, food, daily chemicals, light industry, and other industries.

[0003] Microcrystalline cellulose is a pharmaceutical auxiliary material widely used in the medical industry. In the pharmaceutical industry, it is mainly used as an adhesive, disintegrant, and filler, primarily in the tableting process. It can be used in wet granulation, dry granulation, and direct tableting. Its excellent pressure resistance and disintegration and lubrication properties make it an important pharmaceutical auxiliary material. Due to its unique porous structure, microcrystalline cellulose can also exert a sustained-release effect on pharmaceuticals. Microcrystalline cellulose can also be used as a dietary fiber, an important functional food base in the food industry. It is an ideal food additive and fat substitute.

[0004] Microcrystalline cellulose is available in many varieties, including PH101 (average particle size 40-60 μm, loose density 0.26-0.32 g / mL), PH102 (average particle size 70-100 μm, loose density 0.28-0.33 g / mL), PH 103 (average particle size 45-75 μm, loose density 0.26-0.34 g / mL), and PH 112 (average particle size 90-140 μm, loose density 0.28-0.37 g / mL). There are also special types of microcrystalline cellulose products with high density or small particle size, such as PH301 (average particle size 40-60 μm, loose density 0.34-0.45 g / ml), PH302 (average particle size 90-140 μm, loose density 0.35-0.50 g / ml), and PH105 (average particle size 20-40 μm, loose density 0.2-0.3 g / ml).

[0005] The table below is taken from the product manual of ASAHI in Japan and shows the product parameters listed on the packaging of common microcrystalline cellulose products available on the market.

[0006] [Table 1]

[0007] Microcrystalline cellulose has different application characteristics depending on the particle size and density. In general, the smaller the particle size of microcrystalline cellulose, the more advantageous it is for uniform mixing with other ingredients, such as pharmaceuticals. It is suitable for mixing with materials with small particle sizes or low active ingredient contents to improve content uniformity. Furthermore, conventional microcrystalline cellulose with small particle sizes has the unique advantage of improving tablet strength performance. However, the smaller the particle size of microcrystalline cellulose, the lower its flowability tends to be, making it unsuitable for formulations such as direct compression, significantly limiting its application in pharmaceuticals and food products.

[0008] Small-particle microcrystalline cellulose products have traditionally been produced by dry grinding, sieving, and ball milling, especially in the presence of grinding aids. Chinese Invention Patent CN101481424B discloses ultrafine-powdering microcrystalline cellulose with a particle size of 10 μm or less by decomposition with 60Co-γ irradiation, followed by mechanical grinding and / or chemical decomposition. However, the density of microcrystalline cellulose products produced by these methods is not very high. Commercially available small-particle microcrystalline cellulose products generally have an average particle size D50 of 15–30 μm and a moderate density of 0.2–0.3 g / ml. Therefore, the smaller the particle size, the worse the flowability becomes. This significantly limits industrial applications.

[0009] Chinese invention patent CN109666078A discloses a method for preparing microcrystalline cellulose by high-shear mechanical pretreatment followed by acid hydrolysis. During the pretreatment process, high-shear mechanical forces are used to cut the fibers, improving the accessibility of the acid solution to the cellulose, increasing the rate of penetration of the acid solution into the cellulose and the rate of acid hydrolysis of the acid solution into the amorphous regions of the cellulose, thereby reducing the use of chemicals and reaction time. The density of the microcrystalline cellulose prepared by this method is not improved, and the average particle size of the microcrystalline cellulose product is still above 38.7 μm.

[0010] Chinese invention patent CN110229239A discloses microcrystalline cellulose with high loose density and its manufacturing method. The filter cake obtained by acid hydrolysis is kneaded in a kneader and then spray-dried to obtain a microcrystalline cellulose product with a loose density of 0.6-0.65 g / cm3. However, the particle size of this microcrystalline cellulose product is large, with an average particle size D50 of 45-50 μm.

[0011] Chinese invention patents CN103726378A, CN103526624A, and CN1671743A also disclose methods for preparing microcrystalline cellulose. However, the particle size or loose density of the microcrystalline cellulose products prepared by these methods are not within the scope of the present invention. For example, the particle size is 25 μm or more, or the loose density is much lower than 0.5 g / ml.

[0012] Summary of the Invention The present invention provides a microcrystalline cellulose product with an ultrafine particle size and extremely high density and a method for producing the same, in order to overcome the shortcomings of prior art microcrystalline cellulose products. The microcrystalline cellulose product of the present invention has better performance and wider application fields.

[0013] The technical scheme of the present invention is as follows:

[0014] The present invention provides microcrystalline cellulose particles, characterized in that the microcrystalline cellulose particles have an average particle size D50 of 1 to 25 μm and a loose density of 0.5 to 0.8 g / ml. Preferably, the microcrystalline cellulose particles have an average particle size D50 of 1 to 25 μm and a loose density of 0.52 to 0.75 g / ml. More preferably, the microcrystalline cellulose particles have an average particle size D50 of 10 to 20 μm and a loose density of 0.55 to 0.75 g / ml.

[0015] Preferably, the microcrystalline cellulose particles are obtained from conventional microcrystalline cellulose by high-shear mechanical action, and the solids concentration of the conventional microcrystalline cellulose is 15% to 60% after high-shear mechanical action, and more preferably, the solids concentration of the conventional microcrystalline cellulose is 30% to 50% after high-shear mechanical action.

[0016] Preferably, the high shear mechanical action is performed using a high shear device with a torque of greater than 20 N m. More preferably, the high shear mechanical action is performed using a high shear device with a torque of greater than 50 N m. The high shear device is preferably a screw extruder with high strength and high shear force, such as a screw extruder, screw kneader, or screw extrusion kneader. The high shear device may be continuous or intermittent, and may be divided into multi-stage, multi-step, or repeating processes.

[0017] Another object of the present invention is to provide a method for preparing microcrystalline cellulose particles, which includes a step of subjecting conventional microcrystalline cellulose to high shear mechanical stress using a high shear mechanical stress device, wherein the solids content of the conventional microcrystalline cellulose is 15% to 60% during the high shear mechanical stress. More preferably, the solids content of the conventional microcrystalline cellulose during the high shear mechanical stress is 30% to 50%. The high shear mechanical stress is applied using a high shear mechanical stress device with a torque of 20 N m or more. More preferably, the high shear mechanical stress is applied using a high shear mechanical stress device with a torque of 50 N m or more.

[0018] The term "conventional microcrystalline cellulose" refers to microcrystalline cellulose products with different average particle diameters (D50) and / or loose densities than those of the present invention. These products have an average particle diameter (D50) of more than 25 μm and / or a loose density of 0.50 g / ml or less. Examples include microcrystalline cellulose products prepared from raw materials for preparing microcrystalline cellulose by conventional methods in the art, microcrystalline cellulose filter cakes or semi-finished products prepared from natural cellulose pulp subjected to conventional hydrolysis or electron beam irradiation, and existing commercially available microcrystalline cellulose products. An example of the conventional hydrolysis method involves acid hydrolysis of cellulose pulp at a temperature of 110-170°C and an acid concentration of 0.03-0.35 mol / L, followed by washing and filtration to obtain a filter cake. An example of the electron beam irradiation method involves the production of microcrystalline cellulose by electron beam irradiation at a dose of 0.2 Mrad to 10 Mrad. The raw material of the natural cellulose pulp is not particularly limited and may be any material commonly used in the art for producing microcrystalline cellulose, including, but not limited to, the following raw materials or pulps: wood pulp, hemp pulp, bamboo pulp, cotton, cotton linters, straw, reed, straw pulp, cane bagasse, algae, bacterial microorganisms, etc. The existing commercially available microcrystalline cellulose products include, but are not limited to, microcrystalline cellulose products with code names such as PH101, PH102, PH112, PH301, PH302, PH105, or PH103.

[0019] wherein in the above process, the microcrystalline cellulose particles are obtained from material processed by a high shear device, which optionally further comprises steps of dilution, dispersion, drying, sieving and / or milling.

[0020] Another object of the present invention is to provide the use of said microcrystalline cellulose particles as an adjuvant or carrier in industries such as pharmaceuticals, health foods, food, industry, light industry, daily chemicals, petroleum, personal care, and agricultural chemicals.

[0021] The microcrystalline cellulose particles of the present invention can also be understood as powder, etc. These refer to microcrystalline cellulose products having granular or powdery particles with an average particle size D50 of 1 to 25 μm and a loose density of 0.50 to 0.80 g / ml.

[0022] The high shear force device or equipment used in the present invention can reduce the particle size by applying extremely high shear force and mechanical effects such as pressure and friction. Unlike conventional methods for producing microcrystalline cellulose, the present invention does not use a solid grinding aid during high shear treatment, nor does it use a water-soluble grinding aid such as a salt, making it possible to treat microcrystalline cellulose with high shear.

[0023] The high shear force device or equipment of the present invention may be a continuous or intermittent device, and may be used in multiple repeated steps. Generally, when using a screw device such as an extruder or kneader, the torque is preferably 20 N·m or more. In the present embodiment, the torque is 50 N·m or more and controlled between 50 and 150 N·m. During actual extrusion operations, the torque fluctuates. It is initially low and then increases. For example, it may initially be around 50 N·m and later reach 100 N·m or more. The microcrystalline cellulose product prepared by this method can achieve the particle size and density described in the present invention.

[0024] In the high-shear mechanical processing used in the present invention, the solids concentration of the material is generally 15% to 60%, preferably 30% to 50%. If the material to be processed is hydrolyzed microcrystalline cellulose filter cake and the solids content is too high, an appropriate amount of water can be added before or during processing until the appropriate solids content is reached. If the solids concentration is too low, dewatering can be performed before or during high-shear processing. Dewatering methods can include centrifugation, filtration, pressing, infrared irradiation, hot blowing, air blowing, or a combination thereof. Alternatively, the solids content of the final mixture can be adjusted by adding a high solids content of dried microcrystalline cellulose powder or hydrolyzed microcrystalline cellulose filter cake. If the material to be processed is an existing microcrystalline cellulose powder, an appropriate amount of water can be added before or during processing until the appropriate solids content is reached. The solid microcrystalline cellulose powder may be factory-produced microcrystalline cellulose powder or commercially available existing products, such as, but not limited to, PH101, PH102, PH112, PH301, PH302, PH105, PH103, etc.

[0025] Unlike conventional methods for preparing microcrystalline cellulose products, such as milling, the method of the present invention significantly increases the density of microcrystalline cellulose while reducing the particle size by controlling the mechanical action of high shear force, thereby producing high-performance microcrystalline cellulose products with small particle size and high density.

[0026] In the present invention, the material processed by the high-shear device can be further diluted and dispersed with an appropriate amount of water, and the solid content during dispersion can be controlled to a typical range of 1% to 25%. Examples of the dispersing device that can be used include, but are not limited to, any high-shear dispersing device such as a high-shear mixer, a homogenizer, or a homogenizer pump.

[0027] The diluted and dispersed material can be further dried by spray drying, fluidized bed drying, air flow drying, flash drying, etc. If necessary, the dried material can be further sieved or pulverized.

[0028] In the present invention, when a cellulose raw material or cellulose pulp is used to prepare the hydrolyzed microcrystalline cellulose filter cake, any pulp and source of the cellulose raw material can be used, including, but not limited to, wood pulp, hemp pulp, bamboo pulp, cotton, cotton staple cashmere, straw, reed, straw pulp, sugarcane bagasse, algae, bacterial microorganisms, etc.

[0029] The ultrafine, high-density microcrystalline cellulose products produced by the present invention can be applied to all known applications of microcrystalline cellulose, as well as to all potential or emerging applications, including pharmaceuticals, health foods, industrial and light industries, daily chemicals, petroleum, personal care, and agricultural chemicals. In the pharmaceutical field, its uses include, but are not limited to, binders, disintegrants, excipients, taste masking agents, dispersants, and adsorbents. The products of the present invention can be used in a variety of formulation processes, including, but not limited to, wet granulation, dry granulation, direct compression, extrusion-spheronization, spray drying, pellets, microtablets, coatings, liquid formulations, creams, injections, and sprays. Medicinal applications include herbal medicines. The microcrystalline cellulose powder of the present invention can also be widely used in the food industry. For example, it can be used in various dairy products, such as milk drinks, solid beverages, coffee / tea drinks, and carbonated beverages, as well as meat products, jams, seasonings, soups, frozen foods, yogurt, fermented milk, cheese, and biscuits. In addition to these traditional food applications, the microcrystalline cellulose of the present invention can also be applied in several new fields. For example, due to its unique and delicate taste and taste-masking or taste-modifying function, microcrystalline cellulose can be used as a carrier for flavoring substances, pigments, or other nutrients, particularly in compressed candies. Its excellent functionality and flowability significantly improve the quality and performance of compressed candies. It can also reduce or replace the use of sugar alcohols. Further application examples include, but are not limited to, its use as an encapsulating agent or excipient for active microorganisms in spray drying and tabletting.

[0030] The microcrystalline cellulose product of the present invention has a small particle size and a high loose density, resulting in improved properties such as fluidity and compressibility, and a wide range of applications. In particular, the microcrystalline cellulose product of the present invention has a unique particle shape, consisting of spherical or quasi-spherical particles. Existing commercially available microcrystalline cellulose products all have fibrous cross sections, and no spherical particles exist. Furthermore, the angle of repose of the microcrystalline cellulose of the present invention is smaller than that of UF-702, which has the smallest angle of repose among currently available microcrystalline cellulose products. The microcrystalline cellulose product of the present invention not only possesses excellent fluidity and strong compressibility, making it highly suitable for tableting, but also has a small particle size and a spherical or near-spherical shape, resulting in a fine taste and texture, and the ability to mask odors, making it suitable for the molding of pharmaceuticals and foods.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS Figure 1: Particle structure diagram of the product of Example 1 under a 32x optical microscope Figure 2: Particle structure diagram of the product of Example 1 taken with an optical microscope at 63x magnification Figure 3: Particle structure diagram of commercially available AVICEL PH101 taken with an optical microscope at 32x magnification [Mode for Carrying Out the Invention] The following examples are intended to explain and illustrate the contents of the present invention, and the contents of the examples should not be construed as limiting the protection scope of the present invention.

[0032] The particle size, density, angle of repose and microscope measurement referred to in the present invention are as follows.

[0033] 1. Particle size distribution, measured with a Malvern 2000 laser particle size analyzer.

[0034] 2. How to measure loose density. Take microcrystalline cellulose powder and add it to a dry 100ml measuring cylinder up to the 100ml mark. Let the powder settle naturally. When the top is level, read the powder volume v (ml). Pour out all the powder and weigh it in m (g). Loose density = m / v (g / ml).

[0035] 3. Method for measuring tap density: Place the measuring cylinder containing the loose density measurement material on a vibration meter and vibrate it 500 times. Read the volume V (ml) and convert it into density m / v (g / ml).

[0036] 4. Method for measuring the angle of repose. Use the fixed cone method. Microcrystalline cellulose powder is poured through a funnel into the center of a disk with a certain diameter. The radius of the disk is r. The pouring is stopped until the material on the hypotenuse of the powder accumulation layer flows automatically along the edge of the disk. Measure the height h of the cone formed by the powder accumulation. Calculate the angle of repose θ = arctan(h / r).

[0037] 5. Measurement by optical microscope. Take a small amount of microcrystalline cellulose powder on a glass slide, add a small amount of absolute ethanol to disperse it evenly, then place it under the microscope to observe, adjust the appropriate magnification and make fine adjustments to make the image clear.

[0038] In actual extrusion processing, torque fluctuates. Initially, the torque is low, for example, around 50 N m, and then increases, typically reaching 100-150 N m. When the torque exceeds 150 N m, the equipment reaches its limits. However, all prepared microcrystalline cellulose products can achieve the particle size and density described in this invention when the torque is 100 N m or higher.

[0039] Example 1 Cellulose pulp obtained from commercially available wood is collected and subjected to high-temperature acid hydrolysis (hydrolysis temperature 115-170°C, acid concentration 0.03-0.35 mol / L) for 1-2 hours to obtain hydrolyzed microcrystalline cellulose. This is then filtered and washed to a pH of 4-5, increasing the solid content of the cake to 40%. This solid filter cake is extruded three times in a high-shear extrusion device (a continuous extruder with a high-shear blade) while controlling the torque of the extrusion device to 50-150 N·m. Cooling water is introduced into the middle chamber of the extruder for cooling. The extrudate is diluted with water, stirred, neutralized to a pH of 5-8, and then spray-dried to obtain the microcrystalline cellulose product of the present invention.

[0040] Through particle size, density, and angle of repose measurements, the resulting microcrystalline cellulose particle product had a loose density of 0.670 g / ml and a tapped density of 0.807 g / ml. Its particle size distribution was D10 8.721 μm, D50 19.776 μm, and D90 48.369 μm. The angle of repose was 27.8°.

[0041] The microcrystalline cellulose particle product obtained above was observed under an optical microscope at 32x and 63x magnification, respectively. The results are shown in Figures 1 and 2. It can be seen that the product is spherical or quasi-spherical, with a unique particle shape.

[0042] For comparison, let's take the most popular product on the market, AVICEL PH101 microcrystalline cellulose, and observe its morphology under a 32x optical microscope. The results, shown in Figure 3, reveal the cross-sectional shape of fibers.

[0043] Example 2 Commercially available Vivapur PH102 microcrystalline cellulose powder was used, with an ultimate degree of polymerization of 225. Through particle size and density measurements, the loose density was 0.32 g / ml, the tapped density was 0.44 g / ml, and the particle size distribution D10 was 29.623 μm, D50 was 104.997 μm, and D90 was 227.668 μm.

[0044] 500 g of Vivapur PH102 microcrystalline cellulose powder was weighed and mixed with 500 g of water to achieve a 50% solids content. The resulting filter cake was extruded three times in a high-shear extruder, with the torque controlled between 50 and 150 N·m. The extruder's intermediate chamber was cooled with cooling water. The extrudate was diluted with water, stirred, neutralized to a pH of 5 to 8, and spray-dried to obtain the microcrystalline cellulose product of the present invention.

[0045] Through the measurement of particle size and density, the microcrystalline cellulose product obtained above has a loose density of 0.598g / ml, a tapped density of 0.738g / ml, a particle size distribution D10 of 8.629μm, a D50 of 18.649μm and a D90 of 36.61μm.

[0046] Example 3 Cellulose pulp obtained from commercially available bamboo is collected and acid-hydrolyzed at high temperatures (hydrolysis temperature 115-170°C, acid concentration 0.03-0.35 mol / L) for 1-2 hours to obtain hydrolyzed microcrystalline cellulose, which is then filtered and washed with water until the pH reaches 4-5. The filter cake is diluted with water and neutralized to a pH of 5-8, and then spray-dried to obtain conventional microcrystalline cellulose products. Measurements of the resulting microcrystalline cellulose powder revealed a loose density of 0.440 g / ml, a tapped density of 0.575 g / ml, and a particle size distribution D50 of 39.01 μm.

[0047] The bamboo pulp microcrystalline cellulose filter cake obtained above was adjusted to a solids content of 40% and extruded three times in a high-shear extruder, controlling the torque of the extruder to 50-150 N·m, to obtain bamboo pulp microcrystalline cellulose. Cooling water was introduced into the middle chamber of the extruder for cooling. The extrudate was diluted with water, stirred, neutralized to a pH of 5-8, and then spray-dried to obtain the microcrystalline cellulose product of the present invention.

[0048] Through the measurement of particle size and density, the microcrystalline cellulose product prepared above has a loose density of 0.624g / ml, a tapped density of 0.811g / ml, and particle size distributions of D10 5.613μm, D50 12.221μm and D90 31.201μm.

[0049] Example 4 Cellulose pulp obtained from commercially available hemp fiber is collected and subjected to high-temperature acid hydrolysis (hydrolysis temperature 115-170°C, acid concentration 0.03-0.35 mol / L) for 1-2 hours to obtain hydrolyzed microcrystalline cellulose. The pulp is washed with water to a pH of 4-5, and the filter cake is diluted with water and neutralized to a pH of 5-8. It is then spray-dried to obtain conventional microcrystalline cellulose products. The resulting microcrystalline cellulose powder was quantified and found to have a loose density of 0.388 g / ml, a tapped density of 0.561 g / ml, and a particle size distribution D50 of 36.7 μm.

[0050] The hemp pulp microcrystalline cellulose filter cake obtained above was controlled to a solids content of 40% and extruded three times using a high-shear extruder, with the torque of the extruder controlled to 50-150 N·m. Cooling water was passed through the middle chamber of the extruder for cooling. The extrudate was diluted with water, stirred, neutralized to a pH of 5-8, and then spray-dried to obtain the microcrystalline cellulose product of the present invention.

[0051] The particle size and density measurements of the microcrystalline cellulose product prepared above showed a loose density of 0.619 g / ml, a tapped density of 0.774 g / ml, and particle size distributions of D10 of 6.665 μm, D50 of 14.447 μm, and D90 of 30.297 μm.

[0052] Example 5 Cellulose pulp obtained from commercially available wood is collected and acid-hydrolyzed at high temperatures (hydrolysis temperature 115-170°C, acid concentration 0.03-0.35 mol / L) for 1-2 hours to obtain hydrolyzed microcrystalline cellulose. This is then filtered and washed to a pH of 4-5, increasing the solids content of the cake to 42%. This solid filter cake is extruded three times in a high-shear extrusion device (a continuous extruder with a high-shear blade) with the torque of the extrusion device controlled to 50-150 N·m. Cooling water is introduced into the middle chamber of the extruder for cooling. The extrudate is diluted with water, stirred, neutralized to a pH of 5-8, and then spray-dried to obtain the microcrystalline cellulose product of the present invention.

[0053] The particle size, density, and angle of repose of the microcrystalline cellulose particles obtained above were measured, and the loose density was 0.600 g / ml, the tapped density was 0.730 g / ml, the particle size distribution was D10 8.773 μm, D50 21.459 μm, D90 48.528 μm, and the angle of repose was 30.5°.

[0054] Comparative Example Cellulose pulp obtained from commercially available wood is collected and acid-hydrolyzed at high temperatures (hydrolysis temperature 115-170°C, acid concentration 0.03-0.35 mol / L) for 1-2 hours to obtain hydrolyzed microcrystalline cellulose. This is then filtered and washed to a pH of 4-5 and a cake solids content of 35%. This solid filter cake is extruded three times using a high-shear extruder (a continuous extruder equipped with a high-shear blade). The torque of the extruder is controlled to 14-20 N·m during the extrusion process. Note that the torque gradually increases as water evaporates during the extrusion process, but can be reduced to below 20 N·m by adding an appropriate amount of water. Cooling water is introduced into the middle chamber of the extruder for cooling. The extrudate is diluted with water, stirred, neutralized to a pH of 5-8, and then spray-dried to obtain the microcrystalline cellulose product of the present invention.

[0055] Measurement of particle size and density revealed that the loose density of the obtained microcrystalline cellulose particles was 0.487 g / ml, the tap density was 0.574 g / ml, and the particle size distribution D10 was 11.598 μm, D50 was 37.001 μm, and D90 was 87.476 μm. [Brief explanation of the drawings]

[0056] [Figure 1] Particle structure diagram of the product of Example 1 under a 32x optical microscope [Figure 2] Particle structure diagram of the product of Example 1 taken with an optical microscope at 63x magnification [Figure 3] Particle structure diagram of commercially available AVICEL PH101 taken with an optical microscope at 32x magnification

Claims

1. A method for producing microcrystalline cellulose particles having an average particle size D50 of 1 to 25 μm and a loose density of 0.50 to 0.80 g / ml, comprising the steps of: The method comprises a step of subjecting ordinary microcrystalline cellulose to a mechanical action by high shear force using a high shear force device, wherein the solids concentration of the ordinary microcrystalline cellulose during the mechanical action by high shear force is 15% to 60%, and the mechanical action by high shear force is performed using a high shear force device with a torque controlled between 50 and 150 N m, and the ordinary microcrystalline cellulose is a microcrystalline cellulose product having an average particle size D50 of more than 25 μm and / or a loose density of 0.50 g / ml or less. How to do this.

2. The method of claim 1, wherein the high shear force device is a high strength, high shear force screw extrusion device.

3. The method described in claim 2, characterized in that the screw extrusion device is a screw extruder, a screw kneader or a screw extrusion kneader.

4. 2. The method according to claim 1, wherein the conventional microcrystalline cellulose is a semi-finished product of microcrystalline cellulose obtained from natural cellulose pulp by hydrolysis or electron beam irradiation, or an existing microcrystalline cellulose powder product.

5. 5. The method of claim 4, wherein the raw material source of the natural cellulose pulp comprises wood pulp, hemp pulp, bamboo pulp, cotton, cotton linters, straw, reed, straw pulp, sugarcane bagasse, algae, or bacterial microorganisms.

6. 5. The method of claim 4, wherein the existing microcrystalline cellulose powder product comprises microcrystalline cellulose codenamed PH101, PH102, PH112, PH301, PH302, PH105, or PH103.

7. 7. The method according to claims 1 to 6, characterized in that it optionally further comprises the steps of diluting, dispersing, drying, sieving and / or grinding the material treated by the high shear device to obtain the microcrystalline cellulose particles.

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