JPH037693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a limited length and thickness;
This invention relates to a method for producing cellulose powder having a special shape in the form of short rods. More specifically, the maximum fiber length is 250μ, it contains 20 to 80% short rod-shaped particles with a length of 50μ or more, and the thickness is 250μ.
This invention relates to a method for producing specially shaped cellulose powder for pharmaceutical preparations, which has a particle size of ~20μ, has excellent fluidity, and also has excipient properties. Cellulose powder has traditionally been known as an excellent tablet excipient. However, cellulose powder generally has poor fluidity and often causes trouble during tabletting. For this reason,
Many attempts have been made to improve fluidity. For example, Japanese Patent Application Laid-open No. 19917/1983 describes the idea of hydrolyzing a cellulose raw material and then cutting the fibers. In this case, it is assumed that the pulverization process is mainly carried out in a dry manner, and the hydrolysis merely serves as an aid to the pulverization process. Therefore,
The cellulose is not sufficiently hydrolyzed and the cellulose is crushed while maintaining a fairly strong fiber strength. Furthermore, although there are descriptions of pulverization in a wet state, hydrolysis merely serves as an aid to pulverization, as described above. Furthermore, JP-A-49-88925 describes that cellulose is chemically pulverized during acid hydrolysis.
There is a description that it can be crushed without applying any physical force. Further, US Pat. No. 2,978,446 describes a method of wet grinding in a colloid mill into fine particles of several microns or less. As mentioned above, these techniques not only require a great deal of power to cut the cellulose fibers too finely, or force the physical cutting while maintaining the strength of the cellulose fibers, but also affect the way the cellulose fibers are cut. , they were randomly cut or torn apart in different directions, without distinction between vertical and horizontal directions. As a result, the shape of the obtained cellulose powder was irregular, and the particle sizes were long and short, and included particles of various sizes. Therefore, in order to obtain a powder with a special shape that has both fluidity and shapeability, operations such as sieving and classification are necessary to obtain the desired shape,
It is necessary to take out only particles of the same size, which makes the process complicated, and has the disadvantage that a large amount of unnecessary parts are produced at the same time. In view of this point, the inventor of the present invention, as a result of research, found that after hydrolyzing a cellulose raw material with a cellulose fiber diameter of 2 to 20μ with mineral acid to make a depolymerized product,
Maximum fiber length can be easily achieved by cutting in liquid until the fiber is large enough to pass through the mesh wire mesh.
The present invention was completed based on the discovery that a cellulose powder containing 20 to 80% of short rod-shaped particles with a diameter of 250 μm or 50 μm or more and a thickness of 2 to 20 μm could be obtained. That is, in the present invention, a cellulose raw material having a diameter of 2 to 20 μm is hydrolyzed with mineral acid to form a depolymerized product, and then stirred in a turbulent flow region with a Ray nozzle number of 300 or more to form a 60-mesh wire mesh. This invention relates to a method for producing specially shaped cellulose powder, which is characterized by cutting the cellulose powder in a liquid until it has a size that can pass through a cellulose powder. The cellulose fibers used in the present invention include:
In general, any natural cellulose fiber will work; examples include cotton, cotton linters,
There are hemp, jute, wood pulp, linter pulp, bamboo pulp, bagasse pulp, etc. The thickness of this cellulose fiber is an important factor regulating the shape of the product, so the thickness of the fiber is preferably 2 to 20μ, preferably 5 to 10μ. From an industrial standpoint, it is better to use wood pulp of stable quality. The mineral acids used in the present invention include, for example, hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, etc. Among these, nitric acid has strong penetrating power and tends to reduce the thickness of fibers, so if possible, hydrochloric acid, sulfuric acid, nitric acid, etc. It is better to choose from among phosphoric acids. In particular, sulfuric acid is the most suitable because it causes less damage to the fibers. It should be noted that these acids may be used as a mixture as appropriate. The hydrolysis of the present invention may be carried out under any conditions as long as the average degree of polymerization is adjusted to 100 to 300.
From the viewpoint of less damage to fibers and good yield during hydrolysis, acid concentration of 0.01 to 1.0 is recommended.
It is best to carry out using a specified relatively low concentration of acid and at a temperature of 95°C or higher. When cellulose fibers are hydrolyzed, their fiber strength generally decreases. and the average degree of polymerization is 100
If the average degree of polymerization is 300 or more, the strength of the fibers will be extremely low, and even if weak stirring is applied, the fibers will fall apart and the thickness of the fibers will no longer be maintained. If one attempts to forcefully cut this, a powerful crusher similar to the conventional one would be required, which is not preferable. Therefore, in the present invention, it is necessary to adjust the average degree of polymerization of depolymerized cellulose to 100-300. Cutting in the present invention involves dispersing the depolymerized product in a liquid and stirring it to cause a flow of the liquid, and cutting using the shearing force caused by this flow. . In other words, the depolymerized product whose physical strength has been appropriately reduced is subjected to shearing force in the flow and is cut. At this time, since cellulose fibers with a longer woven fiber length receive a greater force from the liquid flow, it is thought that longer fibers are preferentially cut, resulting in particles with approximately uniform length. The flow of liquid required for this cutting is easily obtained by conventional stirring. The degree of stirring may be such that the liquid in which the cellulose fibers are dispersed is mixed homogeneously, but it is preferable to carry out the stirring in a turbulent flow region of 300 or more when expressed in terms of Reynolds number. The liquid in which the depolymerized product is dispersed is preferably water or an aqueous solution containing an acid, a salt, an organic substance, etc., but even if it is an organic solvent, the liquid will not be cleaved. The concentration at which the depolymerized product is dispersed in the liquid may be any concentration as long as the dispersion liquid flows freely, but it is preferably in the range of 1 to 20% by weight. This is undesirable because at concentrations below 1%, the energy used to stir the liquid is too large compared to the energy used to cut the cellulose fibers, and at concentrations above 20%, the chances of cellulose fibers coming into contact increase. However, this is not preferable because the grinding effect due to contact of the fibers takes precedence over cutting by the fluid, and damage to the cellulose fibers cannot be ignored. The time for stirring the liquid should be adjusted as appropriate depending on the stirring device used, the degree of polymerization of the depolymerized product, the concentration of dispersion in the liquid, etc., and stirring should be continued until the cellulose fibers in the liquid pass through a 60-mesh wire mesh. be. The obtained specially shaped cellulose powder is taken out from the liquid, washed if necessary, and further dried. Any method may be used for drying, but for example,
Drying methods such as spray drying and flash drying are convenient for use in pharmaceutical preparations. The specially shaped powder obtained by the method of the present invention has an average degree of polymerization of 100 to 300 and a substantially uniform particle shape, so it has both appropriate flowability and shapeability. Therefore, it is used when molding powder in fields such as pharmaceuticals, foods, and cosmetics. In particular, when used for tabletting medicines, it has excellent fluidity, allows easy handling, and provides high moldability, making it highly valuable. Hereinafter, it will be explained in more detail with reference to Examples. Example 1 Wood dissolving pulp for acetate with an average degree of polymerization of 720 and a fiber diameter of approximately 5 to 10 μm was immersed in 0.8N sulfuric acid, and
Hydrolysis was carried out at °C for 5 hours to obtain hydrolyzed cellulose with an average degree of polymerization of 180. This hydrolyzed cellulose was filtered and washed with water, and then dispersed in water to form a slurry with a solid content concentration of 5%. Diameter of this slurry
Place in a cylindrical tank 30cm long and 50cm high, with a diameter of 15cm.
The mixture was stirred at a rotation speed of 300 rpm using a 6-blade turbine blade. The Reynolds number at this time was 5800. Stir for 20 minutes, maximum length approximately 200 microns, 50
The proportion of particles larger than microns is 52%, and the fiber diameter is approximately 5 ~
A special shaped cellulose powder with a distribution of 10μ was obtained. Example 2 A dissolving pulp for rayon with a fiber diameter of 5 to 10μ, an average degree of polymerization of 680, and 92% α-cellulose was used as a cellulose raw material, and it was hydrolyzed with 0.5N sulfuric acid at 115°C for 2 hours to obtain an average degree of polymerization of 220. Hydrolyzed cellulose was obtained. This hydrolyzed cellulose was placed in the stirring device used in Example 1 while containing sulfuric acid, and
Stirred at 150 rpm for 1 hour. At this time, the Reynolds number was 1150, and the solid content of the slurry was 7%. The obtained powdered cellulose has a maximum length of approximately 250μ, a proportion of particles of 50μ or more at 38%, and a fiber thickness of approximately 5 to 50μ.
It was 10μ. Example 3 Diameter of cellulose fiber is 3 to 10μ, average degree of polymerization
1250 linter pulp was hydrolyzed using 0.7N phosphoric acid at a temperature of 120℃ for 35 minutes.
Hydrolyzed cellulose with an average degree of polymerization of 250 was obtained. After neutralizing this hydrolyzed cellulose with 1N sodium hydroxide, it was placed in the stirrer used in Example 1,
When stirred in exactly the same manner as in Example 1, the maximum length was 250μ, the proportion of particles of 50μ or more was 63%, and the fiber diameter was 3.
Specially shaped powdered cellulose with a distribution of ~10μ was obtained. Comparative Example 1 Acetate pulp with an average degree of polymerization of 720 was hydrolyzed with 0.8N hydrochloric acid at 80℃ for 20 minutes to achieve an average degree of polymerization of 350.
Depolymerized cellulose was obtained. After washing with water, add 5%
Slurry with solid content concentration, diameter 30cm, height 50cm
The mixture was placed in a cylindrical tank and stirred for 1 hour at a rotation speed of 10 rpm using a 6-blade turbine blade with a diameter of 10 cm. The Reynolds number at this time was 86. The obtained cellulose powder has a maximum fiber length of approximately 800μ, 50μ
The proportion of these particles was 85%. Test Example 1 The cellulose powders obtained in Example 1 and Comparative Example 1 were compressed into tablets using a Kikusui Seisakusho RT-S22-T35 high-speed direct compression machine using an 8 mmφ, 12R punch at a tableting speed of 30 rpm and a molding pressure of 200 kg. did. The variation in tablet weight and tablet hardness were evaluated. The result is the first
Shown in the table. 【table】

Claims (1)

[Claims] 1 A cellulose raw material with a cellulose fiber diameter of 2 to 20μ is hydrolyzed with a mineral acid to obtain a depolymerized product with an average degree of polymerization of about 100 to 300, and then the Raynozzle number is
By stirring in a turbulent region of more than 300, approximately 60
A method for producing specially shaped cellulose powder, which is characterized by cutting it in a liquid until it has a size that can pass through a mesh wire mesh. 2. The production method according to claim 1, wherein the mineral acid consists of at least one selected from hydrochloric acid, sulfuric acid, and phosphoric acid. 3. The manufacturing method according to claim 2, wherein the mineral acid is sulfuric acid. 4. The manufacturing method according to claim 1, wherein the cellulose raw material is wood dissolving pulp made of cellulose fibers with a diameter of 5 to 10 μm. 5. The production method according to claim 1, wherein the cutting is carried out by stirring in water or an aqueous solution containing 1 to 20% by weight of the depolymerized product. 6 Hydrolysis is performed at an acid concentration of 0.01 to 1N and a temperature of 95℃.
The manufacturing method according to claim 1, which is carried out as described above.