JPH0355085B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an artificial culture medium, and more particularly to an artificial culture medium that provides a suitable cultivation environment for various plants and does not generate harmful molds. Conventionally, various artificial culture medium materials have been proposed. In order to promote good growth of plants, all of these artificial culture medium materials have water retention properties necessary for plant survival, and at the same time, they have the ability to retain water-soluble nutrients dissolved in water due to such water retention properties. There is. However, such water-retaining properties mean that artificial culture media provide an extremely suitable environment for the growth of harmful molds. The current situation is that they are proliferating and are causing various harms, not just aesthetics. In view of the current situation, the present inventors have conducted intensive research and have found that by incorporating zeolite-based particles carrying antibacterial metal ions into culture medium materials, they can provide a suitable cultivation environment for various plants while at the same time preventing harmful They discovered that there was no mold growth and completed the present invention. An object of the present invention is to provide an artificial culture medium that provides a suitable cultivation environment for various plants and does not generate harmful molds. The above object is achieved by an artificial culture medium characterized in that the main components are a culture medium material and zeolite particles carrying metal ions having a bactericidal effect. The zeolite-based particles having a bactericidal effect (hereinafter abbreviated as metal-zeolite particles) applied to the present invention are one type of metal ion having a bactericidal effect or It is one that holds two or more types. Preferred examples of metal ions having a bactericidal effect include Ag, Cu, and Zn, and these metal ions can be used alone or in combination. Zeolite is generally an aluminosilicate with a three-dimensionally developed skeleton structure, and generally has a structure of XM ₂ /nO・Al ₂ O ₃・based on Al ₂ O ₃
It is expressed as ySiO ₂・ZH ₂ O. M represents an ion-exchangeable metal ion, usually a monovalent to divalent metal, and n corresponds to this valence. On the other hand, X and y are the coefficients of metal oxide and silica, respectively, and Z
represents the number of water of crystallization. Many types of zeolites are known, differing in their composition ratio, pore diameter, specific surface area, etc. However, the specific surface area of the zeolite solid particles used in the present invention is 150 m ² /g (based on anhydrous zeolite).
Above, the zeolite constituent SiO ₂ /
The Al ₂ O ₃ molar ratio is preferably 1.3 or more and 14 or less, more preferably 1.3 or more and 11 or less. The solution of water-soluble salts of metals with bactericidal activity, such as silver, copper, and zinc, used in the present invention easily undergoes ion exchange with zeolite, so using this phenomenon, the above-mentioned metal ions can be extracted singly or It is a mixed type that can be retained in a zeolite stationary phase, but the zeolite particles that retain metal ions have a specific surface area of 150 m ² /g or more,
Particularly favorable results are obtained when the following two conditions are met: the SiO ₂ /Al ₂ O ₃ molar ratio is 1.3 or more and 14 or less; when it deviates from this range, the bactericidal action tends to be markedly reduced. This is thought to be due to the fact that the absolute amount of metal ions fixed on the zeolite is insufficient in a state where the effect can be exerted. In other words, this is considered to be due to the physicochemical properties of the zeolite, such as the amount of exchange groups, exchange rate, and accessibility. Therefore, it is known as Molekyura sheep.
Zeolites with a large SiO ₂ /Al ₂ O ₃ molar ratio are not preferred for the present invention. Zeolite with a SiO ₂ /Al ₂ O ₃ molar ratio of 1.3 or more and 14 or less can uniformly retain metal ions that have a bactericidal effect, and therefore, by using such zeolite, a sufficient bactericidal effect can be achieved. can get. On the other hand, the acid resistance and alkali resistance of zeolite with a high silica ratio (SiO ₂ /Al ₂ O ₃ molar ratio of more than 14) increase with increasing SiO ₂ , but it takes a long time to synthesize, and it is not economically viable. However, it is not advisable to use zeolites with such high silica ratios. The above-mentioned natural or synthetic zeolite with SiO ₂ /Al ₂ O ₃ ≦14 is advantageous because it is inexpensive and has good acid resistance and alkali resistance in the fields in which the present structure is usually used. From this meaning as well
The SiO ₃ /Al ₂ O ₃ molar ratio is preferably 14 or less. As the zeolite material having a SiO ₂ /Al ₂ O ₃ molar ratio of 14 or less used in the present invention, either natural or synthetic zeolite can be used. For example, natural zeolite is analcime (Analcime).
_SiO2 / _Al2O3 =3.6 _{~ 5.6} ), Chabazite: _SiO2 / _Al2O3 =3.2~6.0 and 6.4~
7.6), Clinoptilolite:
SiO ₂ /Al ₂ O ₃ = 8.5 to 10.5), Erionite (Erionite: SiO ₂ / Al ₂ O ₃ = 5.8 to 7.4), Faujasite (Faujasite: SiO ₂ / Al ₂ O ₃ = 4.2 to 4.6),
mordenite: SiO ₂ /Al ₂ O ₃ = 8.34
~10.0), Philipsite:
SiO ₂ /Al ₂ O ₃ =2.6 to 4.4), and the like. These typical natural zeolites are suitable for the present invention. On the other hand, typical synthetic zeolites include A-type zeolite (SiO ₂ /Al ₂ O ₃ = 1.4-2.4),
-type zeolite (SiO ₂ /Al ₂ O ₃ = 2-3), Y-
_These synthetic _zeolites are suitable as _{the zeolite} material of the _present invention _. . Particularly preferred are
Synthetic A-type zeolites, X-type zeolites and synthetic or natural mordenites. The metal-zeolite particles having bactericidal activity used in the present invention can be prepared using an ion exchange reaction, as described above. The amount of metal in the above metal-zeolite particles (based on dry product at 100°C) is 0.001 to 5% by weight for silver.
On the other hand, regarding the zinc and copper used in the present invention, it is sufficient that the amount of zinc or copper in the metal-zeolite particles (based on dry products at 100°C) is 25% by weight or less, and the preferable range is 0.01 to 15% by weight. . The culture medium used in the present invention refers to materials that provide a suitable cultivation environment for the underground parts of various plants, such as water retention, air permeability, and shape retention. Flakes, granules, pellets, and fibers obtained by molding synthetic polymers such as coalescence, semi-synthetic polymers such as cellulose, vinyl acetal polymers, acrylic polymers, urea polymers, and urethane polymers. Examples include: The above-mentioned culture medium material applied to the present invention is not particularly limited, and may be appropriately selected from the known culture medium materials described in, for example, Japanese Patent Publication No. 57-402343, Japanese Patent Publication No. 57-37291, etc. Just use it. In the artificial culture medium according to the present invention, the culture medium material and the metal-zeolite particles having a bactericidal effect may be simply mixed together.
A more favorable result can be obtained if both are fixed and integrated. That is, when actually cultivating plants using the artificial medium of the present invention, simply mixing the two will result in water supply, etc., no matter how uniformly the two are mixed.
This is because there is a tendency for the two to separate over time due to a difference in their specific gravity, etc., but if they are fixed and integrated in advance, such a phenomenon will not occur. The fixation and integration may be performed, for example, by the method described below. For example, when the medium material is non-foamed polymer fibers or aggregates thereof, the fibers or aggregates are heated and while the polymer is in a semi-molten state, metal-zeolite particles or aggregates thereof are heated. For example, when the medium material is a foam, the metal-zeolite particles are made into a slurry and the foam is poured into the slurry, thereby filling the pores of the foam with metal-zeolite solid particles. The medium material and the metal-zeolite particles can be integrated by such methods. The metal-zeolite particles are preferably in the form of powder particles or aggregates. Examples of the shape of the aggregate include pellets and spheres. When the medium material is fibers or aggregates thereof, the particle size is preferably 1 micron or more in order to stably retain the fibers or aggregates thereof. When the medium material is a foam, the particle size is preferably 50 μm or less in order to smoothly fill the pores of the foam with metal-zeolite particles. The proportion of the metal-zeolite in the whole is preferably 0.01 to 50% by weight (based on anhydrous zeolite). The artificial culture medium mainly composed of metal-zeolite particles and medium materials obtained by the present invention has water retention, air permeability, and fibrous properties necessary for the growth of various plants, and is effective in preventing the generation of harmful molds. It has extremely significant effects. The bonding force between zeolite and antibacterial metal ions such as zinc, silver, and copper is extremely large, unlike the method of simply holding them by physical adsorption on an adsorbent such as activated carbon or alumina. Therefore, an artificial medium containing such metal-zeolite particles has a strong antibacterial effect for a long time. EXAMPLES The present invention will be explained in more detail with reference to Examples below. Production example 1 Using a 50 mm stainless steel polymerization tank with a reflux tube and a stirrer, azobisisobutyronitrile was used as an initiator in a dimethylformamide solvent, and the monomer concentration was 30 mm.
Polymerization was carried out for 16 hours under the conditions of weight %, monomer composition: 50% acrylonitrile, 49% vinylidene chloride, 1% sodium allylsulfonate, and a polymerization temperature of 68°C to obtain a polymerized dope. After recovering the monomer, the viscosity was adjusted with dimethylformamide and extruded into a coagulation bath of a 50% DMF solution using various 500-hole nozzles with a diameter of 0.06 to 0.2 mm. The monomer was then stretched 4 times in boiling water, dried, and then stuffed. It was mechanically crimped using a box-type crimper, and then set using a moist heat setter. This was cut into 50 mm pieces and subjected to the following cultivation test. (The acrylic fiber obtained in this production example is abbreviated as AF.) Production example 2 Average degree of polymerization as PVA: 1200, saponification degree: 99 mol%
A PVF sponge (sheet-like product) with a porosity of about 90% and an average pore diameter of 60μ was produced by formalizing it in the presence of a sulfuric acid catalyst using completely saponified PVA and starch as a pore-forming aid. By adjusting the oxidation conditions, two types of sponges were obtained: a low formalized sponge with a degree of formalization of 65 mol% and a highly formalized sponge with a formalized degree of 83%.These sponges were cut into pieces with a cross section of 2.
A linear object (string-like object) measuring ~3 mm square and 10 to 15 cm in length was used in the following cultivation trial. (The PVF sponge obtained in this production example is abbreviated as PS-1) Production example 3 Collect 250 g of each of the six types of natural and synthetic zeolite powder dry products listed in the column of zeolite materials used in Table 1 below. and add 1/10M silver nitrate aqueous solution to each
500 ml was added and the resulting mixture was kept at room temperature under stirring for 23 hours to perform ion exchange. The silver-zeolite obtained by this ion exchange method was filtered and then washed with water to remove excess silver ions. Next, the water-washed silver-zeolite was dried at 100 to 105°C and ground to obtain a fine powder of silver-zeolite.
The silver content and specific surface area of the dried silver-zeolite product obtained were as shown in Table 1. (Among silver-zeolite conversion products, silver-A type zeolite is _Z1 , silver-X
type zeolite as Z ₂ , silver-Y type zeolite as Z ₃ , silver-natural mordenite (Shin-Tohoku Kagaku Kogyo Co., Ltd.) as Z ₄ , silver-natural mordenite (Anaconda Minerals)
Company) is abbreviated as _Z5 , and silver-natural chabasite is abbreviated as _Z6 . )

[Table] Production Example 4 Collect 250 g of dried fine powder of the four types of natural and synthetic zeolites listed in the column of zeolite materials used in Table 2 below, and add one part of a 1/20M copper sulfate aqueous solution to each.
added. The resulting mixture was stirred at room temperature for 5 minutes.
Holds time. The copper-zeolite obtained by this ion exchange method was suctioned and washed with water until sulfate ions were removed. Next, the washed copper-zeolite was dried at 100 to 105°C and ground to obtain a finely powdered copper-zeolite conversion product. Table 5 shows the copper content and specific surface area of the copper-zeolite conversion product obtained by the above method. (Copper-
Among zeolite conversion products, copper-A zeolite
_Z7 , copper-Y type zeolite is abbreviated as _Z8 , copper-natural mordenite is abbreviated as _Z9 , and copper-natural chaabasite is abbreviated as _Z10 . )

[Table] Production Example 5 Water was added to the various metal-zeolites obtained in Production Examples 3 and 4 to obtain a 50% aqueous slurry.
Next, a PVF sponge was produced in the same manner as in Production Example 2, and the PVF sponge was immersed in the slurry.
The impregnation and squeezing process was repeated to fill the pores of the sponge with metal-zeolite. Obtained metal-
Table 3 shows the types of zeolite-containing sponges and the metal-zeolite content. Nos. 21 to 30) These sponges were cut into cotton-like materials (string-like materials) each having a cross section of 2 to 3 mm square and a length of 10 to 15 cm, and these were subjected to the following cultivation test. (obtained in this production example)
(PVF sponge is abbreviated as PS-2) The metal-zeolite content in the sponge was measured as follows. That is, the absolute dry weight of the PVF sponge obtained in Production Example 2 before being impregnated with the aqueous slurry was measured in advance, the metal-zeolite-containing sponge impregnated with the aqueous slurry was again completely dried, and the weight was determined from the weight difference. Example 1 After the acrylic fiber obtained in Production Example 1 was allowed to sufficiently absorb water, a cultivation test was conducted using a mixture of various metal-zeolites obtained in Production Examples 3 and 4 as a medium. The cultivated product is Sansevieria that has been grown in natural sphagnum moss for one year, and is grown once every two days in various media.
100 ml of tap water was poured in and changes in growth and appearance were observed. The results are shown in Table 3. (Nos. 1 to 10) Example 2 After the PVF sponge obtained in Production Example 2 was sufficiently absorbed, various metal-zeolites obtained in Production Examples 3 and 4 were added and blended and used as a medium. A cultivation test was conducted in exactly the same manner as in Example 1. The results are shown in Table 3. (Nos. 11 to 20) Example 3 A cultivation test was conducted in exactly the same manner as in Example 1, except that the metal-zeolite-containing sponge obtained in Production Example 5 was used as the culture medium material. The result is the third
Shown in the table. (No.21-30)

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【table】

Claims (1)

[Scope of Claims] 1. An artificial culture medium characterized by containing a culture medium material and zeolite particles carrying metal ions having a bactericidal effect. 2. The artificial culture medium according to claim 1, wherein the culture medium material is made of a synthetic polymer foam. 3. The artificial culture medium according to claim 2, wherein the synthetic polymer foam is a porous polyvinyl acetal polymer. 4. The artificial culture medium according to claim 1, wherein the culture medium material is made of a non-foaming polymer. 5. The artificial culture medium according to claim 4, wherein the non-foaming water-absorbing polymer is an absorbent acrylic polymer or a polyvinyl acetal polymer. 6. The artificial medium according to any one of claims 1 to 5, wherein the metal ion is a silver ion, a copper ion, or a zinc ion. 7. Claims 1 to 7, wherein the zeolite particles have a specific surface area of 150 m ² /g or more (based on anhydrous zeolite), and the SiO ₂ /Al ₂ O ₃ molar ratio of the zeolite constituents is 1.3 or more and 14 or less The artificial medium according to any of Item 6. 8. Any one of claims 1 to 7, wherein the zeolite particles carrying metal ions contain 0.001% by weight or more and 15% by weight or less (based on dry product at 100°C) of metal ions. Artificial medium as described.