JPH058645B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a culture medium for growing plants, and particularly to a culture medium for agriculture and horticulture that uses an inorganic fiber molded product as a base material. [Conventional technology] Traditionally, natural soil or granulated materials have often been used as medium materials for plant cultivation. Culture medium materials have also been developed.
As such artificial culture medium materials, it is known to use calcined minerals such as vermiculite and perlite, as well as inorganic fibers such as rock wool (Japanese Patent Publication No. 12642/1983). The invention primarily aims at improving soil quality by mixing inorganic fibers into clay soil to increase its ability to adsorb and retain water. Recently, in Europe, hydroponic cultivation, which uses rock wool, a type of inorganic fiber, molded into mats, cubes, and boards as a culture medium has become popular. Such rock wool culture medium material is produced by, for example, molding rock wool using a water-soluble phenolic resin as a binder, spraying an aqueous solution of an acidifying agent, fertilizer, and a surfactant onto the surface of the rock wool, and drying the mixture (as disclosed in Japanese Patent Application Laid-open No. Publication No. 58-141731). [Problems to be solved by the invention] However, when such an inorganic fiber molded medium material is used as a seedling raising medium material (for sowing seeds, germination, and making seedlings), some types of plants may not germinate. The seedlings were not uniform and the growth after germination was not smooth, making them unsatisfactory as a medium for raising seedlings. In Europe as well, in order to avoid problems during germination, seeds are often sown in regular soil to form seedlings, which are then transplanted to Rockwool medium. As a result of various studies, the present inventors discovered that aqueous phenolic resin, which is used as a binder when manufacturing inorganic fiber molding medium materials, causes germination problems and poor growth. This problem could be solved by changing the manufacturing conditions. [Means for Solving the Problems] The object of the present invention is to provide an inorganic fiber molded medium material that solves the problem of germination failure and poor growth. This was achieved using a plant cultivation medium material whose base material is an inorganic fiber molded product formed by molding inorganic fibers as an engaging agent. The present invention will be explained in detail below. Examples of inorganic fibers used in the present invention include Kotsuku wool, glass wool, and ceramic fibers. In particular, blast furnace slag by-produced from blast furnaces in steel plants and/or natural rocks such as basalt, andesite, and diabase are used as kyupora, Rock wool (also called rock wool, slag wool, or mineral wool), which is melted in an electric furnace or the like and blown into fibers by centrifugal force and/or fluid pressure such as air or steam, can be used favorably. Inorganic fibers such as rock wool are fiber aggregates in which fibers are accumulated in layers, and in order to form them into mats, cubes, boards, etc., a binder is required to bond the fibers together. be. Usually, inorganic fiber molded products for building materials and industrial materials use resol-type phenolic resin that uses a soda (Na) catalyst as a binder during the production of phenolic resin, in terms of strength, water resistance, and cost. There are many things. However, when inorganic fiber molded products made from resol-type phenolic resins using soda catalysts are used as medium materials for plant cultivation, particularly as medium materials for raising seedlings, the inventors have found that the above-mentioned problems in germination and poor growth are likely to occur. It was made clear by The reason for this is
It is thought that the sodium ions remaining in the phenolic resin used as a binder are eluted by irrigation and impede the germination and rooting of plant seeds.
In contrast, with resol-type phenolic resins using potassium (Ka) catalysts, such problems do not occur or occur only to a small extent. Resol-type phenolic resin using a potash catalyst is made by heating the raw material phenol and formaldehyde in the presence of a caustic potash catalyst to about 40 to 70 degrees Celsius to react.
It is produced by neutralizing with para-toluenesulfonic acid or the like. The amount of caustic potash catalyst used is 0.1 to 5% by weight, preferably 0.5 to 1.5% by weight based on the raw material.
Weight%. The amount of the resol type phenolic resin using a potash catalyst relative to the inorganic fiber is 0.5 to 5% by weight, preferably 1 to 3% by weight in terms of solid content. If the amount of phenolic resin used is less than 0.5% by weight relative to the inorganic fibers, the adhesion between the fibers will be insufficient and the shape retention of the molded product will not be sufficient, causing it to deform or fall apart when handled. If it is more than 5% by weight, the base material will become too hard and roots will not penetrate into the medium material. The resol-type phenolic resin can be added to the inorganic fibers by spraying an aqueous solution or dispersion of the phenolic resin during the production of the inorganic fibers, or by impregnating a pre-manufactured inorganic fiber aggregate with the aqueous solution or dispersion of the phenolic resin. It is best to do this by Next, the resin-sprayed inorganic fiber material is heated in a curing furnace or the like to produce a base material. The curing conditions may be the same as when using a conventional soda-catalyzed resol type phenolic resin as a binder, for example, 10 curing conditions at 250°C.
Just heat it for about a minute. A medium material for plant cultivation is required to have appropriate water absorption and water retention properties, and for this reason it is preferable to subject the inorganic fibers to a hydrophilic treatment. For such hydrophilic treatment, it is preferable to add a nonionic surfactant or a polyhydric alcohol. The amount of these surfactants added is 0.05 to 5% by weight, preferably 0.3 to 1% by weight based on the inorganic fiber.
is appropriate. If it is less than 0.05% by weight, there is no effect, and even if it exceeds 5% by weight, the hydrophilicity will not improve further and the economical efficiency will decrease. The density of the inorganic fiber molded product can be selected as appropriate depending on the intended use of the culture medium.
Usually 50 to 250 Kg/m ³ , preferably 60 to 150 Kg/m ³ . If it is less than 50 kg/m ³ , the balance between water retention and aeration will be poor, resulting in poor plant growth. If it exceeds 250Kg/ ^m3 , the germination rate will deteriorate. The culture medium of the present invention may contain various additives, such as hydrophilicity imparting agents, acidifying agents, fertilizers, etc., as necessary. Examples of the hydrophilicity imparting agent include alkyloxyethylene ether, alkylphenylypolyoxyethylene ether, alkylpolycarbonyloxyethylene, N,N-di(polyoxyethylene)alkanamide, fatty acid polyhydric alcohol ester, fatty acid polyhydric alcohol Nonionic surfactants such as polyoxyethylene ether, fatty acid sucrose ester, fatty acid monoglyceride, N,N-di(alkanol)alkanamide, etc., such as ethylene glycol, propylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-
Examples include polyhydric alcohols such as butanediol, glycerin, butanetriol, polyethylene glycol, polypropylene glycol, polybutylene glycol, and diglycerin. The usage amount of these hydrophilicity imparting agents is 0.05% based on the inorganic fiber base material.
~5% by weight, preferably 0.3-1% by weight is suitable. If it is less than 0.05% by weight, there is no effect;
Even if it exceeds 5% by weight, there is no improvement in hydrophilicity and the economical efficiency decreases. In addition, inorganic fibers such as rock wool are
If it is soaked in water, the PH of the soaking water will rise, so if it is used as a base material for a plant that prefers a neutral or weakly acidic medium, an acidifying agent should be added. is preferred. Examples of acidifying agents include mineral acids such as sulfuric acid, nitric acid, and hydrochloric acid, or ammonium salts of these mineral acids, organic acids such as acetic acid, citric acid, tartaric acid, humic acid, and nitrohumic acid, natural minerals such as zeolite, Examples include humus such as peace moss. Further, although the base material of the seeding medium does not need to contain fertilizer components, it is preferable to incorporate a fertilizer component into the base material when the medium material is to be used, for example, as a mat for raising paddy rice seedlings or as a home gardening medium material. As for the fertilizer content, nitrogen fertilizers include ammonium sulfate, ammonium chloride, ammonium nitrate, urea, etc., potassium fertilizers include potassium sulfate, potassium chloride, etc., and phosphate fertilizers include lime superphosphate, ammonium phosphate, etc. can be given. The catalytic component potassium contained in the binder of the culture medium base of the present invention serves as a potassium fertilizer. These fertilizers may be simple fertilizers or mixed fertilizers. The type and amount of fertilizer to be added are determined as appropriate depending on the use of the culture medium. The above hydrophilicity imparting agent, acidifying agent, fertilizer, etc.
The binder may be mixed with the resol-type phenolic resin using a potash catalyst as a binder or added separately to the inorganic fibers and then heat-cured. Alternatively, the binder may be heat-cured to the inorganic fibers and the base material These may be added after production. The shape of the plant cultivation medium material of the present invention is pine,
It can be molded into any shape such as a cube, board, or granule. The fibers of the base material manufactured in this way are oriented in the horizontal direction of the base material, so if it is a board-oriented base material used for plant growing beds, it can be manufactured with the horizontal fibers intact. good. However, in order to improve the penetration of roots into pine for paddy rice seedlings and cube-oriented substrates for raising seedlings and growth, cutting the horizontal fiber substrate to an appropriate thickness and arranging them at an angle of 90 degrees allows the fibers to be oriented in the direction of fiber orientation. Since it is vertical, it can be used as a base material for vertical fibers. These culture medium materials may be cut if necessary or covered with a plastic film such as black polyester or silver polyurethane. [Example] Resol type phenol resin (potassium content 4000 ppm
and 8,000 ppm) aqueous dispersion or, for comparison, an aqueous dispersion of resol type phenol resin (soda content: 6,000 ppm) using a soda catalyst, each containing 1% by weight of the inorganic fiber in terms of solid content, and polyoxyethylene as a hydrophilicity imparting agent. Spray nonyl phenyl ether to 0.5% by weight on inorganic fibers and heat at 250°C.
The phenolic resin was cured by heating in a curing oven for 10 minutes to form base materials A, B, and C with a density of 80 kg/ ^m3.
were manufactured respectively. Cut the base material A, base material B, and base material C, and turn them 90 degrees to obtain cubes A (example) and cube B (example) with fiber orientation direction of 10 cm x 10 cm x 7.5 cm (height) vertically.
and Cube C (comparative example). Next, in order to check the water resistance of the cubes due to the binder, Cube A and Cube C were immersed in water, and the lengths in the fiber orientation direction and perpendicular direction were measured.
The increase rate was determined by setting the standard length as 100. The test results are listed in Table 1.

[Table] Furthermore, for Cube A and Cube C, the bending strength, compressive strength (20% compression), and water absorption rate were measured, respectively. The test results are listed in Table 2.

[Table] Next, Cube A, Cube B, and Cube C
Germination tests and growth tests were conducted on cucumbers (Natsu-Autumn Setsei No. 2) using the following methods. For the germination test, seeds were sown in cubes that had been watered in advance, and the germination status was observed on the 5th day after sowing. In addition, in the growth test, Otsuka No. 1 fertilizer was applied to the germinated cucumbers at a concentration of 1/2 of the garden trial formulation.
The growth status of the seedlings was measured on the 21st day after sowing. The germination test results and growth test results are listed in Table 3.

[Table] [Effects of the Invention] As explained above, the present invention achieves the following by using an inorganic fiber molded product using a potash-catalyzed resol type phenol resin as a binder as a base material for a plant cultivation medium. It can significantly improve the germination rate of plant seeds and promote plant growth.

Claims (1)

[Claims] 1. A plant cultivation medium material characterized by having an inorganic fiber molded product as a base material using a potash-catalyzed resol type phenolic resin as a binder.