JP2016202083A - Artificial soil particles, and artificial soil culture medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide artificial soil particles capable of absorbing and holding moisture content which is required for plant growth while securing air permeability.SOLUTION: An artificial soil particles 50 comprises a fiber lump body 10 which is made by aggregating a plurality of fibers 1. In the fiber lump body 10, the fibers 1 are fastened with each other by a binding material including first resin 3 having hydrophobic property and second resin 4 at least partially hydrophilized, and the fiber lump body 10 is constituted such that the fibers 1 continuously contact via the first resin 3, and the fibers 1 contact in a dot state via the second resin 4.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an artificial soil particle provided with a fiber mass formed by collecting a plurality of fibers, and an artificial soil medium using the artificial soil particle.

  In recent years, plant factories that grow plants such as vegetables in an environment where growth conditions are controlled are increasing. The plant factories so far have mainly focused on hydroponic cultivation of leafy vegetables such as lettuce, but recently there is a movement to try cultivation of root vegetables that are not suitable for hydroponic cultivation in plant factories.

  In the development of artificial soil for cultivating root vegetables and the like, a function capable of appropriately maintaining and managing water retention is required while achieving plant growth ability equivalent to natural soil. In particular, it is necessary to absorb and retain an appropriate amount of water in the artificial soil culture medium in order to realize an optimal cultivation schedule according to the type of plant.

  As a conventional artificial soil having water retention, an artificial aggregate having a porous structure in which particles made of an inorganic material are entangled with an organic material made of organic plant fibers, etc., and solidified in a granular form by a binder. It has been proposed (see, for example, Patent Document 1). The artificial aggregate of Patent Document 1 intends to improve water retention by using organic plant fibers or the like as an organic material.

JP 2001-204245 A

  Since the artificial aggregate of Patent Document 1 uses a highly hydrophilic organic plant fiber to form a porous structure, it is considered that moisture can be retained in the pores of the porous structure. However, agglomerates obtained by granulating organic plant fibers have strong moisture retention on the surface of the agglomerates because organic plant fibers are present on the surface of the agglomerates. When a soil culture medium is formed, moisture may be retained in the gaps between the aggregates and may not be easily discharged.

  The present invention has been made in view of the above problems, and uses artificial soil particles that can absorb and retain moisture necessary for plant growth while ensuring air permeability, and the artificial soil particles. An object is to provide an artificial soil medium having a good moisture environment.

The characteristic configuration of the artificial soil particles according to the present invention for solving the above problems is as follows:
Artificial soil particles having a fiber mass formed by aggregating a plurality of fibers,
The fiber lump is that the fibers are fixed to each other by a binder containing a first resin having hydrophobicity and a second resin at least partially hydrophilized.

  According to the artificial soil particle of this configuration, the fibers of the fiber block are fixed to each other by the binder including the first resin having hydrophobicity and the second resin at least partially hydrophilized. For this reason, the surface of the fiber appropriately includes a hydrophobic region and a hydrophilic region. As a result, the artificial soil particles have an excellent balance between air permeability and water retention, and can maintain a good moisture environment suitable for plant cultivation.

In the artificial soil particles according to the present invention,
The fiber lump is preferably configured such that the fibers are in continuous contact via the first resin, and the fibers are contacted in dots via the second resin.

  According to the artificial soil particle of this configuration, the fiber lump has a continuous continuous contact region because the fibers are in continuous contact via the first resin. Thereby, the area | region where a water | moisture content does not exist easily in artificial soil particle | grains can be formed, and air permeability can be ensured. On the other hand, in the fiber lump, since the fibers contact with each other via the second resin, a plurality of hydrophilic dot-shaped contact regions are formed. A space is formed between the dot-like contact areas, and moisture can be retained. As described above, the artificial soil particles of this configuration ensure a certain level of air permeability and water retention by changing the contact form (adhesion state) between the fibers, and are substantially independent of the water retaining material. A good moisture environment suitable for plant cultivation can be maintained only by the structure of the artificial soil particles.

In the artificial soil particles according to the present invention,
The binder preferably includes a soft resin having an elastic modulus of 5 to 50 MPa as the first resin, and a hard resin having an elastic modulus of 100 to 1500 MPa as the second resin.

  According to the artificial soil particles of this configuration, since the soft resin and the hard resin having appropriate elastic modulus are selected as the first resin and the second resin, respectively, the hydrophobic continuous contact region and the hydrophilic point are selected. Each of the contact areas is surely formed in the fiber block, and a good moisture environment suitable for plant cultivation can be maintained.

In the artificial soil particles according to the present invention,
The binder preferably includes a latex rubber as the first resin and a polyolefin resin as the second resin.

  According to the artificial soil particle of this configuration, since an appropriate resin is selected as the resin contained in the binder, the hydrophobic continuous contact area and the hydrophilic point-like contact area are in the fiber mass. Each is formed reliably and can maintain a good moisture environment suitable for plant cultivation. Moreover, since inexpensive latex rubber is used as the first resin, artificial soil particles having excellent strength can be configured while reducing manufacturing costs.

In the artificial soil particles according to the present invention,
In the binder, it is preferable that the blending ratio of the first resin and the second resin is adjusted to 0.3: 1 to 5: 1 by weight ratio.

  According to the artificial soil particle of this configuration, since the blending ratio of the first resin and the second resin is adjusted to an appropriate range, the hydrophobic continuous contact region and the hydrophilic point in the fiber mass The contact area is formed at an appropriate ratio. As a result, the balance between air permeability and water retention is excellent, and a good moisture environment suitable for plant cultivation can be maintained.

In the artificial soil particles according to the present invention,
When 100 cc of water is absorbed with respect to 100 cc of the fiber mass, the initial liquid phase rate of the fiber mass is set to 10 to 30% by volume, and the initial gas phase rate is set to 40 to 60% by volume. Preferably it is.

  According to the artificial soil particles of this configuration, since the initial liquid phase rate and initial gas phase rate of the fiber mass are set in an appropriate range, the artificial soil particles have an excellent balance between air permeability and water retention Therefore, a good moisture environment suitable for plant cultivation can be maintained.

The characteristic configuration of the artificial soil culture medium according to the present invention for solving the above problems is as follows.
The artificial soil particles according to any one of the above are used.

  According to the artificial soil culture medium of this configuration, since the artificial soil particles of the present invention are used, the balance between air permeability and water retention is excellent. Therefore, the water environment of the artificial soil medium can be maintained in a good state suitable for plant cultivation.

FIG. 1 is a schematic diagram of artificial soil particles according to the first embodiment. FIG. 2 is a model diagram conceptually showing the relationship between the voids of the artificial soil particles of the present invention and the moisture absorbed in the voids. FIG. 3 is a schematic diagram of artificial soil particles according to the second embodiment.

  Hereinafter, the embodiment regarding the artificial soil particle which concerns on this invention, and an artificial soil culture medium is described based on FIGS. 1-3. However, the present invention is not intended to be limited to the configurations described in the embodiments and drawings described below.

<Artificial soil particles>
(First embodiment)
FIG. 1 is a schematic diagram of artificial soil particles 50 according to the first embodiment. The artificial soil particle 50 has a fiber lump 10 formed by granulating the fibers 1. The fiber lump 10 is formed as a granular material in which the fibers 1 are entangled, and there are voids 2 between the fibers 1, and the voids 2 can absorb and retain moisture. That is, since the fiber lump 10 serving as the base of the artificial soil particle 50 has water retention, when the external environment becomes wet, the moisture existing in the external environment is absorbed and retained in the artificial soil particle 50. Can do. Thus, the artificial soil particle 50 can ensure air permeability with the external environment to a certain level or more while maintaining the water retention required as soil. As a result, plant root rot and the like can be prevented. On the other hand, when the external environment is in a dry state, the moisture retained in the gap 2 of the fiber lump 10 is released to the external environment. Thereby, a plant can utilize a water | moisture content easily. As described above, the artificial soil particles 50 achieve a good balance between excellent water retention and air permeability by the voids 2 existing between the fibers 1 forming the fiber lump 10.

  The fibers 1 constituting the fiber lump 10 are preferably organic fibers so that sufficient moisture can be retained in the voids 2 in the fiber lump 10. Since organic fibers are relatively flexible, the fibers 1 constituting the fiber lump 10 are intertwined in a complex manner to form a large number of voids 2. Thereby, the water retention of the fiber lump 10 is increased, and the water absorbed by the artificial soil particles 50 can be held as water that can be easily used by plants, so-called easy water. As a result, plant growth can be promoted. As the organic fiber, either a natural organic fiber or a synthetic organic fiber can be used. Examples of natural organic fibers include silk, wool, cotton, and cellulose fibers. Examples of synthetic organic fibers include nylon fibers, polyester fibers, vinylon fibers, aramid fibers, rayon fibers, polypropylene fibers, polyethylene fibers, polyurethane fibers, and the like. Among these organic fibers, cellulose fibers that are natural organic fibers are preferably used. In addition, it is also possible to use what mixed natural organic fiber and synthetic organic fiber as the fiber 1 used for the fiber lump 10.

  The fiber length of the fibers 1 constituting the fiber lump 10 is related to the water retention of the artificial soil particles 50. By adjusting the fiber length of the fiber 1, the adsorptive power between the fiber 1 and water can be controlled. The fiber length of the fiber 1 is preferably 0.5 to 2000 μm. When the fiber length is shorter than 0.5 μm, sufficient water retention cannot be obtained. On the other hand, if the fiber length is longer than 2000 μm, the adsorptive power between the water and the fiber becomes too strong, and the easy-to-use water that can be used by the plant decreases.

  The particle size of the artificial soil particles 50 is appropriately selected depending on the plant to be cultivated, but is preferably 1 to 10 mm, more preferably 2 to 8 mm, and further preferably 2 to 5 mm. When the particle size of the artificial soil particles 50 is less than 1 mm, when the artificial soil medium is configured using the artificial soil particles 50, the gap between the artificial soil particles 50 is reduced, and moisture is excessively retained by the capillary force of the gap. Will be. As a result, it is difficult to absorb oxygen from the roots of the plant due to reduced drainage, and root rot may occur. On the other hand, when the particle size of the artificial soil particles 50 exceeds 10 mm, the gap between the artificial soil particles 50 becomes large when the artificial soil medium 50 is configured using the artificial soil particles 50, the drainage becomes excessive, and the plant It may be difficult to absorb sufficient moisture, or the artificial soil culture medium may become sparse and the plant may fall over. The particle size of the artificial soil particles 50 can be adjusted by sieving or the like.

  The artificial soil particles 50 may contain an inorganic porous material having high hygroscopicity. In this case, when the artificial soil particles 50 are irrigated, moisture is quickly absorbed by the artificial soil particles 50 through the inorganic porous material and is held in the void 2. Therefore, the plant can use the moisture absorbed in the artificial soil particles 50 even in the initial stage of irrigation or when the amount of irrigation is small. As a result, the number of times of watering the cultivated plant can be reduced, and the labor of the operator can be reduced. Examples of the inorganic porous material that can be used include diatomaceous earth, pearlite, vermiculite, zeolite, bentonite, clay, and porous glass beads. These inorganic porous materials may be used alone or in combination of two or more. A preferred inorganic porous material is diatomaceous earth. When granulating the fiber lump 10 serving as the base of the artificial soil particles 50, when diatomaceous earth is added to the fiber 1, the diatomaceous earth absorbs moisture and exhibits viscosity, so that the fibers 1 can be easily bonded to each other.

  Here, since the artificial soil particle 50 is a lump in which the fibers 1 are intertwined, the fibers 1 are exposed on the surface. For this reason, when the artificial soil medium is configured using the artificial soil particles 50, depending on the type of the fiber 1, moisture is strongly retained in the gaps formed between the artificial soil particles 50, and the drainage performance is reduced. The air permeability may deteriorate. Therefore, in the present invention, in forming the fiber lump 10 serving as the base of the artificial soil particles 50, a binder containing a hydrophobic first resin and a second resin that has been at least partially hydrophilized is used. The fibers 1 are fixed to each other. The fiber lump 10 formed in this manner is appropriately provided with a hydrophobic region formed by the first resin and a hydrophilic region formed by the second resin, so that a balance between air permeability and water retention is achieved. The artificial soil particles 50 can be excellent.

  FIG. 2 is a partially enlarged view of the artificial soil particle 50 shown in FIG. 1. The artificial soil particle 50 using the first resin and the second resin has a void 2 and moisture absorbed in the void 2. It is the model figure which showed the relationship with W notionally. 2A shows the state of the void 2 of the artificial soil particle 50 before water is supplied by irrigation or the like, and FIG. 2B shows the state of the void 2 of the artificial soil particle 50 where the water W supplied by irrigation or the like is supplied. It shows the state which met. The fiber lump 10 fixes a plurality of fibers 1 to each other using a binding material including a hydrophobic first resin 3 and a hydrophilic second resin 4 that is at least partially hydrophilized. , Granulated. Here, the first resin 3 is preferably a soft resin having an elastic modulus of 5 to 50 MPa. When the fiber 1 is granulated using such a soft resin, as shown in FIG. 2A, the fibers 1 are continuously contacted and fixed via the first resin 3. Thereby, the hydrophobic area | region where the water | moisture content W does not exist easily in the fiber lump 10 is formed, and the air permeability of the artificial soil particle 50 is ensured. When the elastic modulus of the first resin 3 is larger than 50 MPa, it becomes difficult to continuously fix the fibers 1 and it becomes difficult to form a hydrophobic region in the artificial soil particle 50. However, when the elastic modulus of the first resin 3 is smaller than 5 MPa, the fibers 1 fixed by the first resin 3 are easily peeled off, and it is difficult to maintain the shape of the artificial soil particles 50 for a long period of time. The second resin 4 is preferably a hard resin having an elastic modulus of 100 to 1500 MPa. When the fiber 1 is granulated using such a hard resin, as shown in FIG. 2A, the fiber 1 comes into contact with the second resin 4 as a contact and is fixed in a dot shape. Thereby, a plurality of dot-like contact areas are formed in the fiber lump 10. Since the hydrophilic space | gap 2 is formed between these several dotted | punctate contact areas, the artificial soil particle 50 can ensure fixed water retention. When the elastic modulus of the second resin 4 is smaller than 100 MPa, it becomes difficult to fix the fibers 1 to each other in a dot shape, and the water retention is lowered. However, when the elastic modulus of the second resin 4 is greater than 1500 MPa, the melting temperature of the resin is high, so that the fibers 1 need to be exposed to a high temperature in order to fix the fibers 1, and the fibers 1 may be deteriorated. Thus, the artificial soil particles 50 of the present invention can change the contact state between the fibers 1 by adjusting the hardness (elastic modulus) of the resin used for the binder, and as a result, the artificial soil particles A certain hydrophobic region can be formed while securing a hydrophilic region in the region 50. In particular, on the surface of the artificial soil particle 50, since the fibers 1 are continuously in contact with and fixed to each other via the first resin 3 by the first resin 3 of the soft resin, the surface of the artificial soil particle 50 is constant. The hydrophobic region is formed, and the hydrophilicity of the surface of the fiber lump 10 is maintained so as not to become too high. Therefore, as shown in FIG. 2 (b), for example, even when water is supplied to the artificial soil particles 50 by irrigation, the surface is not completely covered with moisture, and the artificial soil medium 50 is used. It is possible to ensure a certain level of air permeability in the gap formed between the artificial soil particles 50. Moreover, since a certain hydrophobic area | region is also contained in the fiber lump 10, the air permeability of the artificial soil particle 50 itself can be ensured. The artificial soil particle 50 of the present invention ensures a certain level of air permeability and water retention by changing the contact form (fixed state) between the fibers 1 and is substantially artificial soil without relying on a water retention material or the like. Only the structure of the particles 50 can maintain a good moisture environment suitable for plant cultivation.

  Examples of the first resin 3 include natural latex, polychloroprene latex, styrene-butadiene latex, styrene-butadiene-vinylpyridine latex, acrylonitrile-butadiene latex, carboxyl-modified styrene-butadiene latex, and carboxyl-modified styrene-butadiene-vinylpyridine latex. A soft resin such as carboxyl-modified acrylonitrile-butadiene latex, carboxyl-modified methyl methacrylate-butadiene latex, and acrylate latex can be used. Of these soft resins, carboxyl-modified styrene-butadiene latex, carboxyl-modified acrylonitrile-butadiene latex, and acrylate latex are preferable. These soft resins are relatively hydrophilic among latex and can constitute artificial soil particles having excellent strength.

  As the second resin 4, for example, a polyolefin resin such as polyethylene or polypropylene, a polyester resin such as polyethylene terephthalate or polybutylene terephthalate, or a hard resin such as polystyrene resin such as polystyrene can be used. However, these hard resins need to be at least partially hydrophilized. A preferred hard resin is a polyolefin-based resin that has been at least partially hydrophilized.

  The mixing ratio of the first resin 3 and the second resin 4 is preferably adjusted to 0.3: 1 to 5: 1 by weight ratio. When the blending ratio of the first resin 3 and the second resin 4 is smaller than 0.3: 1 (that is, when the first resin 3 is less than 0.3 times the second resin 4), the artificial soil particles 50 In such a case, a sufficient hydrophobic region cannot be formed, and the air permeability may be lowered. On the other hand, when the blending ratio of the first resin 3 and the second resin 4 is greater than 5: 1 (that is, when the first resin 3 exceeds 5 times the second resin 4), the artificial soil particles 50 are excessive. Since a hydrophobic region is formed, water retention may be reduced.

  By the way, in order for a plant planted in soil to grow, it is necessary to ensure that the soil has a certain level of air permeability and water retention after irrigation. For example, when the volumetric water content of the soil is maximized by one irrigation, the air permeability may deteriorate and the root rot of the plant may occur. In addition, when the volumetric water content of the soil is not sufficiently increased by one irrigation, it is difficult to supply sufficient moisture to the plant over a long period of time, so it is necessary to shorten the irrigation interval. In this respect, the artificial soil particle 50 of the present invention is formed by granulating fibers using a binder including the first resin 3 and the second resin 4 in the fiber lump 10 serving as a base. An appropriate balance with water retention is maintained, and when the artificial soil medium is constructed using the artificial soil particles 50, the liquid phase rate and the gas phase rate can be set in appropriate ranges. The liquid phase rate and the gas phase rate of the artificial soil particles 50 can be evaluated by the initial liquid phase rate and the initial gas phase rate. Here, the “initial liquid phase ratio” is the amount of water (liquid phase ratio in a three-phase distribution) retained in the artificial soil particles when 100 cc of water is absorbed with respect to 100 cc of the artificial soil particles in a dry state. Yes, the “initial gas phase rate” is the porosity (the gas phase rate in the three-phase distribution) maintained in the artificial soil particles when 100 cc of water is absorbed with respect to 100 cc of the artificial soil particles in the dry state. . In order to maintain the air permeability and water retention of the artificial soil particles 50 in a well-balanced manner, the initial liquid phase rate of the fiber mass 10 is 10 to 30% by volume, and the initial gas phase rate is 40 to 60% by volume. Preferably, the initial liquid phase rate of the fiber lump 10 is set to 15 to 30% by volume, and the initial gas phase rate is set to 45 to 60% by volume. When the initial liquid phase rate of the fiber lump 10 is set to less than 10% by volume or the initial gas phase rate is set to be greater than 60% by volume, it becomes difficult to supply sufficient moisture to the plant. On the other hand, when the initial liquid phase rate of the fiber lump 10 is set to be larger than 30% by volume or the initial gas phase rate is set to be less than 45% by volume, the air permeability may be lowered and the root rot of the plant may occur. In addition, in order for a plant to grow, since it is necessary to hold | maintain the moisture content more than fixed after irrigation, it is preferable to set the maximum volume moisture content of the artificial soil particle 50 to 30 volume% or more.

(Second embodiment)
FIG. 3 is a schematic diagram of the artificial soil particles 51 according to the second embodiment. The artificial soil particle 51 is obtained by coating the outer surface of the fiber block 10 constituting the artificial soil particle 50 of the first embodiment with the aqueous film 20. In FIG. 3, the entire outer surface of the fiber lump 10 is covered with the water permeable membrane 20, but it is sufficient that at least a part of the outer surface is covered. The water permeable membrane 20 controls the water permeability between the fiber lump 10 and the external environment, and is a membrane having fine pores through which moisture can pass, or moisture penetrates from one side and moves to the other side. It can be configured as a possible permeable membrane. The artificial soil particles 51 can adjust water retention and water absorption by changing the size, film thickness, and material of the micropores in the water permeable membrane 20. The water permeable membrane 20 also contributes to maintaining the strength and improving the durability of the artificial soil particles 51. Therefore, the artificial soil particles 51 according to the present embodiment can take in moisture from the external environment through the water permeable membrane 20 and release moisture to the external environment, but also have excellent strength and durability. The value of use is high.

  The water-permeable membrane 20 forms a thickness from the outer surface of the fiber lump 10 to a slightly infiltrated state so as to reinforce the entangled portions of the fibers constituting the fiber lump 10 (portions where the fibers contact each other). May be. Thereby, the intensity | strength and durability of the artificial soil particle 51 can further be improved. The film thickness of the water-permeable membrane 20 is set to 1 to 200 μm, preferably 10 to 100 μm, and more preferably 20 to 60 μm. The material of the water permeable membrane 20 is preferably insoluble in water and hardly oxidized, for example, polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride resins such as polyvinyl chloride and polyvinylidene chloride, and polyesters such as polyethylene terephthalate. And styrene resins such as polystyrene. Of these, polyethylene is preferred. It is also possible to use gelling agents such as polyethylene glycol and sodium alginate.

<Method for producing artificial soil particles>
The artificial soil particle 50 is substantially composed of the fiber lump 10. Therefore, the manufacturing method of the fiber lump 10 will be described first. The fiber lump 10 is obtained by granulating the fiber 1 by a known granulation method such as rolling granulation, fluidized bed granulation, stirring granulation, compression granulation, extrusion granulation or the like. In preparing the fiber lump 10, first, a predetermined amount of fiber 1 is put into a stirring and mixing granulator, and a granulation operation is performed while adding a binder containing the first resin 3 and the second resin 4 little by little. Do. At this time, an inorganic porous material may be added to the fiber 1. By this granulation operation, the fibers 1 are entangled with each other and agglomerated, and a granulated product in which the first resin 3 and the second resin 4 are adhered to the surface of the fiber 1 is formed. Next, when this granulated product is put into a dryer and heated to a temperature equal to or higher than the melting temperature of the first resin 3, the fibers 1 are bonded in a state of continuous contact via the first resin 3. Further, when the temperature is raised to the melting temperature of the second resin 4 or higher, the fibers 1 are bonded in a state where they are in contact with dots via the second resin 4 dispersed in the granulated product. When the granulated product is cooled in this state, the fiber 1 is fixed in a state of continuous contact through the first resin 3, and the fiber 1 is fixed in a state of contact in a dotted manner through the second resin 4, The fiber lump 10 is completed. The fiber lump 10 can be used as the artificial soil particle 50 shown in FIG. The artificial soil particles 50 are dried and classified as necessary to adjust the particle size.

  The artificial soil particles 51 are obtained by forming the water permeable membrane 20 on the surface of the fiber block 10. As a method for forming a water-permeable film, a case where a polyethylene emulsion is used will be described as an example. First, the fiber lump 10 is put into a suitable container, and about half of the volume (occupied volume) of the fiber lump 10 is added to immerse the water in the gap 2 of the fiber lump 10. Next, a polyethylene emulsion of 1/3 to 1/2 of the volume of the fiber lump 10 is added to the fiber lump 10 soaked with water. The polyethylene emulsion may be mixed with additives such as pigments, fragrances, bactericides, antibacterial agents, deodorants, and insecticides. Next, the polyethylene emulsion is impregnated from the outer surface of the fiber lump 10 while rolling so that the polyethylene emulsion uniformly adheres to the outer surface of the fiber lump 10. At this time, since the water has soaked into the center of the fiber lump 10, the polyethylene emulsion stays near the outer surface of the fiber lump 10. Thereafter, the polyethylene fiber is melted while the fiber lump 10 to which the polyethylene emulsion is adhered is dried with a dryer, and the polyethylene is fused to the fibers 1 near the outer surface of the fiber lump 10 to form the water permeable membrane 20. As a result, the outer surface of the fiber lump 10 is covered with the water-permeable membrane 20 of polyethylene, and the artificial soil particles 51 in which certain shielding properties and rigidity are established are completed. In the water permeable membrane 20, when the polyethylene melts, the solvent contained in the polyethylene emulsion evaporates to form a porous structure. The porous structure functions as a communication hole that communicates the fiber lump 10 and the external environment. Therefore, the artificial soil particles 51 are those in which water permeability between the internal fiber mass 10 and the external environment is ensured. The artificial soil particles 51 are dried and classified as necessary to adjust the particle size.

  An artificial soil medium was prepared using the artificial soil particles of the present invention, and the water retention characteristics of the artificial soil medium were evaluated. In this example, the water retention amount (initial liquid phase rate) retained in the artificial soil medium by one irrigation and the gas phase rate (initial gas phase ratio) maintained in the artificial soil medium during one irrigation The water retention characteristics of the artificial soil medium were evaluated from these measured values.

[Preparation of artificial soil medium]
<Example 1>
Cellulose fibers (BWW40, average fiber length 0.2 mm, average fiber diameter 0.02 mm, manufactured by Rettenmeier) 300 g and organic porous diatomaceous earth (Radiolite (registered trademark) 300, Showa Chemical Industry Co., Ltd.) 300 g) into a stirring and mixing granulator (manufactured by G-Labo Co., Ltd.), stirring and rolling until uniform, adding 860 g of granulating liquid (binding material) to granulate, A fiber lump impregnated with the granulation liquid was formed. The granulation liquid consists of (1) 100 g of acrylate latex (Nipol (registered trademark) LX811H, manufactured by Nippon Zeon Co., Ltd.) as the first resin, and (2) polyolefin resin emulsion (Sumitomo Seika Co., Ltd.) as the second resin. Manufactured by Sepoljon G315, concentration 40% by weight), 10 g of sodium alginate (reagent manufactured by Wako Pure Chemical Industries, Ltd.) as a thickener, and 650 g of water, and each material is sufficiently mixed into water. What was stirred at normal temperature for 24 hours until it disperse | distributed uniformly was used. The fiber lump is dried at 60 ° C. using a dryer, and the cellulose fibers are continuously fixed with latex (first resin), and then the dryer is heated to 100 ° C. to raise polyolefin resin (second resin). Resin) was melted, and the cellulose fibers were fixed to each other in the form of dots, which were cooled to obtain artificial soil particles of Example 1.

<Example 2>
The artificial soil particles of Example 2 were obtained by granulating the same mixture of cellulose fiber 300 g and diatomaceous earth 300 g used in Example 1 by adding 940 g of the granulating liquid. The granulation liquid consists of (1) 80 g of carboxyl-modified styrene-butadiene latex (Nipol (registered trademark) LX430, manufactured by Nippon Zeon Co., Ltd.) as the first resin, and (2) polyolefin resin emulsion (Sumitomo) as the second resin. Seigyo Co., Ltd., Sepoljon G315, concentration 40% by weight) 200 g, sodium alginate (reagent made by Wako Pure Chemical Industries, Ltd.) 10 g as a thickener, and water 650 g were mixed and stirred. . The production process of the artificial soil particles is the same as that in Example 1.

<Example 3>
The artificial soil particle of Example 3 was obtained by granulating the same mixture of cellulose fiber 300 g and diatomaceous earth 300 g used in Example 1 by adding 980 g of the granulating liquid. The granulating liquid consists of (1) 200 g of acrylate latex (Nipol (registered trademark) LX811H, manufactured by Nippon Zeon Co., Ltd.) as the first resin, and (2) polyolefin resin emulsion (Sumitomo Seika Co., Ltd.) as the second resin. Manufactured by Sepoljon G315, concentration 40% by weight) 120 g, sodium alginate (reagent manufactured by Wako Pure Chemical Industries, Ltd.) 10 g as a thickener, and water 650 g were mixed and stirred. The production process of the artificial soil particles is the same as that in Example 1.

<Example 4>
The artificial soil particles of Example 4 were obtained by granulating the same mixture of cellulose fiber 300 g and diatomaceous earth 300 g used in Example 1 by adding 960 g of the granulating liquid. The granulating liquid consists of (1) 250 g of acrylate latex (Nipol (registered trademark) LX811H, manufactured by Nippon Zeon Co., Ltd.) as the first resin, and (2) polyolefin resin emulsion (Sumitomo Seika Co., Ltd.) as the second resin. Manufactured by Sepoljon G315, concentration 40% by weight), 10 g of sodium alginate (reagent manufactured by Wako Pure Chemical Industries, Ltd.) as a thickener, and 650 g of water were mixed and stirred. The production process of the artificial soil particles is the same as that in Example 1.

<Comparative Example 1>
The artificial soil particles of Comparative Example 1 were obtained by granulating a mixture of the same cellulose fiber 300 g and diatomaceous earth 300 g used in Example 1 by adding 960 g of the granulating liquid. The granulation liquid is (1) 300 g of carboxyl-modified styrene-butadiene latex (Nipol (registered trademark) LX430, manufactured by Nippon Zeon Co., Ltd.) as the first resin and sodium alginate (Wako Pure Chemical Industries, Ltd.) as the thickener. (Reagent manufactured) 10 g and 650 g of water were mixed and stirred. That is, the granulation liquid used in Comparative Example 1 does not contain the second resin. The fiber mass was dried at 60 ° C. using a dryer, and the cellulose fibers were fixed continuously with latex (first resin), which was cooled to obtain artificial soil particles of Comparative Example 1.

<Comparative example 2>
The artificial soil particles of Comparative Example 2 were obtained by granulating a mixture of the same cellulose fiber 300 g and diatomaceous earth 300 g used in Example 1 by adding 960 g of the granulating liquid. The granulation liquid consists of (2) 300 g polyolefin resin emulsion (Sumitomo Seika Co., Ltd., Sepoljon G315, concentration 40% by weight) as the second resin, and sodium alginate (Wako Pure Chemical Industries, Ltd.) as the thickener. (Reagent manufactured) 10 g and 650 g of water were mixed and stirred. That is, the first resin is not included in the granulation liquid used in Comparative Example 2. The fiber lump was dried at 100 ° C. using a dryer, and the cellulose fibers were fixed to each other in a dot shape with a polyolefin resin (second resin), which was cooled to obtain artificial soil particles of Comparative Example 2.

  Each artificial soil particle of Examples 1 to 4 and Comparative Examples 1 and 2 was adjusted to a particle size of 2 to 4 mm by sieving, and an artificial soil medium for use in an evaluation test of moisture retention characteristics was prepared using this.

[Evaluation of water retention characteristics of artificial soil medium]
In evaluating the moisture retention characteristics of the artificial soil medium, first, the three-phase ratio (liquid phase ratio, solid phase ratio, and gas phase ratio) of the artificial soil particles was measured. Each artificial soil adjusted to have a moisture content of 5% by weight or less in a stainless steel cup (diameter 50 mm x height 51 mm, capacity 100 cc) provided with a number of drain holes with a diameter of about 1 mm on the bottom. 100 cc of medium was added and 100 cc of water was added dropwise. The moisture content of the artificial soil culture medium is measured using an infrared heating dry mass measurement type moisture content meter (model number: MOC-120H, manufactured by Shimadzu Corporation). 3 to 6 g, and the heating temperature was set to 120 ° C. The liquid phase ratio (volume%) of the artificial soil culture medium was calculated by measuring the weight change of each artificial soil culture medium and dividing this by the weight of each artificial soil culture medium after dropping water. The solid phase ratio of the artificial soil medium was measured using a digital real volume measuring device (model number: DIK-1150, manufactured by Dairika Kogyo Co., Ltd.) with respect to 100 cc of each artificial soil medium before dropping water. The gas phase ratio (volume%) of the artificial soil medium was calculated by subtracting the solid phase ratio (volume%) and the liquid phase ratio (volume%) from the three-phase total (100 volume%) of the artificial soil medium. The liquid phase rate and the gas phase rate obtained by the first irrigation were taken as the initial liquid phase rate and the initial gas phase rate, respectively. Table 1 shows measured values of the initial liquid phase rate and initial gas phase rate of each artificial soil medium containing the artificial soil particles of Examples 1 to 4 and Comparative Examples 1 and 2.

  The artificial soil medium containing the artificial soil particles of Examples 1 to 4 has an initial liquid phase rate of 10 to 30% by volume within the range of the present invention, and an initial gas phase rate within the range of the present invention 40 to 40%. 60% by volume. As described above, it was confirmed that the artificial soil medium containing the artificial soil particles of the present invention maintains an appropriate water retention and air permeability in a well-balanced manner. On the other hand, the artificial soil medium containing the artificial soil particles of Comparative Example 1 in which the fiber lump is formed using only the first resin has a low initial liquid phase rate and a high initial gas phase rate, which is sufficient. Water retention was not obtained. The artificial soil medium containing the artificial soil particles of Comparative Example 2 in which the fiber mass is formed using only the second resin has a high initial liquid phase rate and a low initial gas phase rate, and sufficient air permeability is obtained. I couldn't.

  The artificial soil particles according to the present invention and the artificial soil medium using the artificial soil particles can be used in agriculture and horticulture in home gardens, plant factories, indoor greening, and the like.

DESCRIPTION OF SYMBOLS 1 Fiber 2 Cavity 3 1st resin 4 2nd resin 10 Fiber lump 50,51 Artificial soil particle

Claims (7)

Artificial soil particles having a fiber mass formed by aggregating a plurality of fibers,
The fiber lump is an artificial soil particle in which the fibers are fixed to each other by a binder including a first resin having hydrophobicity and a second resin that is at least partially hydrophilized.   The artificial fiber according to claim 1, wherein the fiber block is configured such that the fibers are in continuous contact via the first resin, and the fibers are in contact with dots via the second resin. Soil particles.   The artificial soil particle according to claim 1 or 2, wherein the binder includes a soft resin having an elastic modulus of 5 to 50 MPa as the first resin, and a hard resin having an elastic modulus of 100 to 1500 MPa as the second resin.   The artificial binder particle according to any one of claims 1 to 3, wherein the binding material includes latex rubber as the first resin and includes a polyolefin-based resin as the second resin.   The artificial material according to any one of claims 1 to 4, wherein the binder is adjusted such that a mixing ratio of the first resin and the second resin is 0.3: 1 to 5: 1 by weight. Soil particles.   When 100 cc of water is absorbed with respect to 100 cc of the fiber mass, the initial liquid phase rate of the fiber mass is set to 10 to 30% by volume, and the initial gas phase rate is set to 40 to 60% by volume. The artificial soil particle according to any one of claims 1 to 5.   The artificial soil culture medium using the artificial soil particle as described in any one of Claims 1-6.

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