JP2979135B2 - Novel aggregate of natural polymer fine particles and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention provides a novel aggregate of natural polymer fine particles and a method for producing the same. In ordinary dry mechanical pulverization, strong reagglomeration of the fine particles generated during the pulverization occurs, and it is difficult to disperse the particles again.
However, a natural polymer microparticle aggregate obtained by adding a substance having an affinity to the natural polymer to the natural polymer and grinding the natural polymer is covered with the added affinity substance around the microparticles. Therefore, it does not re-aggregate during storage, and is easily dispersed in a solvent in which the affinity substance is dissolved at the time of use, whereby a dispersion suspension of natural polymer fine particles is obtained. It is easy to uniformly mix or mix this fine particle dispersion suspension with another liquid or paste-like substance. Further, by selecting an affinity substance to be added, a substance in which fine particles are sufficiently dispersed by an operation such as kneading with a solid substance that is difficult to disperse with natural polymer fine particles alone can be produced. Due to these properties, a natural polymer, which has been difficult to form into fine particles, can be dispersed as fine particles, and can be used for materials, foods, and the like that utilize the natural properties of the natural polymer.

[0002]

2. Description of the Related Art In the case of producing natural polymer fine particles by mechanical pulverization in a dry manner, re-agglomeration of the generated fine particles occurs, so that the obtained particles are of the order of several tens of microns and their particle size distribution is also small. wide. In a method utilizing a chemical treatment such as wet mechanical grinding or acid hydrolysis, 10
Although it is possible to produce submicron microparticles, the resulting microparticles are suspensions, and their concentration is limited to tens of percent by weight, occupying a large volume. In addition, when the concentration is increased, the paste becomes a highly viscous paste, and the method of transport in the used process is also limited. For this reason, its use has been limited to the field where it is mixed and mixed with a solution or a paste-like substance.

When the fine particles produced as a suspension are simply dried by a method such as freeze-drying in order to easily use the fine particles as a dry powder, the fine particles are strongly agglomerated, and it is difficult to disperse the fine particles again. Therefore, it is necessary to go through a process such as coating the surface with another substance, and there is a problem that the manufacturing process is complicated and the cost is increased.

In a method for producing a natural polymer by wet mechanical grinding or chemical treatment, fine particles are obtained as a suspension. Further, in order to make the powder into a dry powder for easy use, a special coating treatment or the like is required. Is required, and a large amount of acidic or alkaline water or solvent becomes waste liquid. Therefore, there is a problem that the cost is increased as a whole for the treatment, collection and reuse. Until now, there has been no attempt to produce dry fine particles having a narrow particle size distribution and a relatively uniform particle size by simple mechanical pulverization by adding a solid substance having another affinity to a natural polymer by a dry method.

[0005]

When a natural polymer is simply mechanically pulverized by a dry method, it is difficult to finely pulverize the natural polymer due to the toughness of the polymer. Further, since strong reaggregation of the fine particles generated during the pulverization occurs, the particles have a wide particle size distribution. On the other hand, in chemical treatments such as wet pulverization and acid hydrolysis, the obtained fine particles are in the form of a suspension, and their use has been limited. Further, in order to facilitate the use as a dry powder, a treatment such as coating with another substance was required to prevent reaggregation. Therefore, there is a problem that the manufacturing process is complicated and the cost is increased due to the treatment of the generated waste liquid and the like. Therefore, the natural polymer fine particles are pulverized in a dry manner while preventing reaggregation, and the product is obtained as an aggregate of dry fine particles having a relatively uniform particle size, and the aggregate does not cause reaggregation during storage, Easy to disperse in solvent when used,
Developed dry fine particles that can be uniformly mixed and mixed with liquid and paste-like substances as a fine particle dispersion suspension, and that can be sufficiently dispersed by mixing directly with solid substances. If so, its industrial use is wide.

According to the present invention, it is possible to produce natural polymer fine particles having a uniform particle size, which were difficult by the method already obtained with a patent (registration number: Patent No. 2560235), and to greatly expand the use thereof. It was done to make it possible.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, after adding a small amount of a solid substance having an affinity to a natural polymer, a vibrating pulverizer. It has been found that, if pulverized using such a method, it is possible to prevent re-aggregation of the generated fine particles, and at the same time, it is possible to produce a dry fine particle aggregate in which the periphery of the fine particles is covered with an affinity substance, and based on these findings, completed the present invention. I came to.

That is, in the present invention, the primary fine particles generated during the pulverization of the natural polymer are covered with another substance to prevent reaggregation and to stably retain the fine particles even after the production. In this case, the particles can be easily dispersed in fine particles. The reagglomeration of the fine particles that occurs during milling is due to physical entanglement and the formation of new bonds on the surface of the fine particles.
This re-coagulation force is strong, and it is not easy to disperse it in the original fine particles even by using a method such as ultrasonic irradiation in a solvent.
Natural polymers have many reactive functional groups such as hydroxyl groups and amino groups in the molecule, and strong hydrogen bonds and covalent bonds formed between these functional groups during grinding cause re-aggregation It is a big factor.

In order to prevent the formation of bonds that cause aggregation, it is necessary to block the functional group of the natural polymer by some method. However, when the functional group is chemically modified by a chemical treatment, the natural properties of the natural polymer are lost.
In order to solve this problem, pulverization is performed using the formation of weak hydrogen bonds between the functional groups of the natural polymer and other substances, and if the state can be maintained after pulverization, reaggregation during storage will occur. It does not happen and can be easily dispersed when used.

The present inventors have proposed a solid substance having an affinity for a hydroxyl group or an ether bond in a molecule and capable of forming a weak hydrogen bond with a natural polymer, that is, natural oligosaccharides, polysaccharides, and proteins. Alternatively, a chemically synthesized polyether, polyalcohol, or natural polymer derivative may be
If about 20% by weight is added and pulverized by a vibration pulverizer or the like, a weak hydrogen bond is formed between the functional group of the affinity substance and the functional group of the natural polymer during the pulverization, and the resulting natural polymer is formed. The inventors have invented that an aggregate of dried natural polymer fine particles in which aggregation of fine particles is prevented and the periphery of the fine particles is entirely or partially covered with an affinity substance is obtained. This aggregate of fine particles can be easily dispersed in a solvent or the like at the time of use without causing reaggregation of the fine particles during storage. Further, the fine particles are fine particles having a relatively uniform particle size and a narrow particle size distribution. Until now, such an aggregate of natural polymer fine particles has not been obtained.

In the present invention, a weak hydrogen is added between the generated natural polymer fine particles and the affinity substance by adding a small amount of the affinity substance to the natural polymer and mechanically pulverizing it in a dry manner. By forming the bond, aggregation is prevented, and it is basically possible to produce a natural polymer fine particle aggregate covered with the affinity substance according to claim 1. This does not deny the addition of non-affinity additives and the like in addition to the affinity substance.

[0012]

The novel aggregate of natural polymer fine particles according to the present invention is obtained as a dry powder, and does not re-aggregate during storage. Further, as the affinity substance to be mixed, any of a water-soluble substance and an organic solvent-soluble substance can be selected. Therefore, in addition to being used as various suspensions, it can be mixed and mixed with a liquid or paste-like substance or directly kneaded with a solid substance. Further, since the particle diameter of the fine particles is relatively uniform, it is possible to highly disperse them in other materials. From these properties, a wide range of applications to various materials and foods using the natural polymer fine particles are possible.

[0013]

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Example 1 An example is shown in which cellulose is used as a natural polymer and polyethylene glycol is used as an affinity substance to be added.
The raw material cellulose used was CF11 manufactured by Whatman, which is a high-purity fibrous cellulose derived from cotton, and the polyethylene glycol used was a primary reagent having a molecular weight of 2,000,000 manufactured by Wako Pure Chemical Industries. First, cellulose (50 grams) whose adsorbed water content was reduced to 0.5% by weight or less by drying under reduced pressure, and polyethylene glycol of 2 to 20% by weight based on the cellulose were put in the same pulverizing container, and were used for 120 minutes using a vibration ball mill. Dry pulverized. The obtained aggregate of the fine particles of cellulose in cellulose was poured into water, which is a good solution of polyethylene glycol, and dispersed by stirring for 5 minutes. Table 1-1 shows the particle size distribution of the dispersed cellulose fine particles.
Shown in As comparative data, Table 1-2 shows the particle size distribution when cellulose containing about 7% by weight of adsorbed moisture and cellulose which was dried to make the amount of adsorbed moisture 0.5% by weight or less were individually ground in the same manner.

[Table 1-1]

[Table 1-2]

Comparison between Table 1-1 and Table 1-2 shows that when polyethylene glycol was added and pulverized, the particle size distribution was narrower and the particle size was relatively uniform as compared with the case of cellulose alone. Clearly, fine particles are obtained. Cellulose has about 7% by weight adsorbed moisture in a standard environment (temperature 20 ° C., relative humidity 65%). When polyethylene glycol was added and pulverized in the presence of the adsorbed water, a lump-shaped aggregate of fine particles was obtained. However, as is evident from Table 1-3, the particle size distribution was comparable to the powdered product when dried.

[Table 1-3]

Example 2 Polyvinyl alcohol (degree of polymerization: 3500, partially saponified type), soluble starch,
Table 2 shows the particle size distribution of the fine particles obtained when lactose or glucose was added in an amount of 15% by weight and pulverized under the same conditions as in Example 1, and the obtained fine particle aggregate was dispersed in water. All of the added affinity substances used were special grade or first grade reagents manufactured by Wako Pure Chemical Industries. Also in this case, fine particles having a uniform particle size were obtained.

[Table 2]

Example 3 Cellulose acetate was added to cellulose as an affinity substance.
% By weight, and pulverized under the same conditions as in Example 1. The particle size distribution of the fine particles when the obtained fine particle aggregate was dispersed in acetone is shown in Table 3. As the added cellulose acetate, a first-class reagent manufactured by Wako Pure Chemical Industries, Ltd. was used. Also in this case, fine particles having a uniform particle size were obtained.

[Table 3]

Example 4 Collagen purified from cowhide was mixed with 15% by weight of polyethylene glycol as an affinity substance, pulverized under the same conditions as in Example 1, and the obtained fine particle aggregate was dispersed in water. Table 4 shows the particle size distribution of the fine particles in this case. Also in this case, fine particles having a uniform particle size were obtained.

[Table 4]

Example 5 Chitin purified from crab shells was mixed with 15% by weight of polyethylene glycol as an affinity substance, pulverized under the same conditions as in Example 1, and the obtained fine particle aggregate was dispersed in water. Table 5 shows the particle size distribution of the fine particles obtained in the above case. Again,
Fine particles having a uniform particle size were obtained.

[Table 5]

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Claims (2)

(57) [Claims] Claims: 1. Natural oligosaccharides, polysaccharides, proteins or chemically synthesized polyethers, polyalcohols, and natural polymer derivatives having an affinity for natural macromolecules are used to form natural polymer microparticles as a whole. Or, a partially covered dry natural polymer particle aggregate. 2. adding a natural oligosaccharide, a polysaccharide, a protein or a chemically synthesized polyether, a polyalcohol, or a natural polymer derivative having an affinity to the natural polymer to the natural polymer; A method for producing an aggregate of dried natural polymer fine particles in which an affinity substance added by dry mechanical pulverization completely or partially covers fine particles of a natural polymer.