JP2016106629A - Artificial soil particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide artificial soil particle capable of efficiently absorbing and retaining moisture required for growth of plant.SOLUTION: There is provided artificial soil particle 50 containing fiber aggregate 10 formed by granulation of fiber 1, which contains water absorption facilitating material 3 enhancing early stage water absorption of fiber aggregate 10. The water absorption facilitating material 3 containing at least one selected from a group consisting of organic macromolecule material 3a and/or hydrophilization material, as well as inorganic porous material 3b. The organic macromolecule material 3a contains at least one hydrophilic substance selected from a group consisting of agar, polyethylene glycol, carrageenan, gelatin, pectin, alginic acid, methylcellulose, carboxymethylcellulose, and salt or derivative thereof, polyacrylamide water absorptive resin, polyvinyl alcohol water absorptive resin, as well as polyalkenyleneoxide water absorptive resin.SELECTED DRAWING: Figure 2

Description

  The present invention relates to artificial soil particles having a fiber mass formed by granulating fibers.

  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 order to cultivate root vegetables in a plant factory using artificial soil, it is necessary to develop artificial soil particles that are excellent in basic performance as soil, high in quality, and easy to handle. Artificial soils are required to have unique functions that are difficult to realize in natural soils, such as reducing the number of watering of plants and facilitating the management of water content.

  Patent Document 1 proposes an artificial aggregate in which particles made of an inorganic material are entangled with an organic material made of organic plant fibers and the like, and solidified into particles with a binder. This artificial aggregate is intended to improve water retention by using organic plant fiber or the like as an organic material.

JP 2001-204245 A

  In the development of artificial soil, a function capable of appropriately maintaining and managing water retention is required while achieving the same plant growth ability as natural soil. In particular, it is necessary to efficiently absorb and retain moisture in the artificial soil medium in order to reduce the number of watering times for plants and to realize an optimal cultivation schedule according to the type of plant.

  In this respect, the artificial aggregate of Patent Document 1 is an inorganic material material entangled with organic plant fibers or the like and granulated with a binder, and uses organic plant fibers with high hydrophilicity. It is considered that moisture can be retained in the gaps between the porous structures in the aggregates by absorbing into the aggregates. However, once the aggregates formed by granulating organic plant fibers are in a dry state, a large amount of air enters the gaps in the aggregates. As a result, water could hardly be soaked, and as a result, there was a risk that water would be discharged without sufficiently retaining moisture in the artificial soil. That is, conventional artificial soil may not be able to efficiently absorb moisture from the initial stage of irrigation.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide artificial soil particles that can efficiently absorb and retain moisture necessary for plant growth.

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 granulating fibers,
The object is to include a water absorption promoting material that enhances the initial water absorption of the fiber mass.

  According to the artificial soil particle of this configuration, since the water absorption promoting material that enhances the initial water absorption of the fiber lump is included, the water supplied by irrigation or the like can be quickly absorbed and retained in the fiber lump. it can. As a result, even in the initial stage of irrigation and even when the amount of irrigation is small, the plant can use the water necessary for the growth of the plant, reducing the number of watering and reducing the labor of the operator. it can.

In the artificial soil particles according to the present invention,
The water absorption promoting material preferably includes at least one selected from the group consisting of an organic polymer material and / or a hydrophilizing material, and an inorganic porous material.

  Organic polymer materials, hydrophilizing materials, and inorganic porous materials are suitable materials as water absorption promoting materials that easily absorb moisture from the external environment. Therefore, according to the artificial soil particle of this structure, the water | moisture content supplied by irrigation etc. can be rapidly absorbed into a fiber lump body, and can be hold | maintained reliably.

In the artificial soil particles according to the present invention,
The organic polymer material includes agar, polyethylene glycol, carrageenan, gelatin, pectin, alginic acid, methylcellulose, carboxymethylcellulose, and salts or derivatives thereof, polyacrylamide-based water absorbent resin, polyvinyl alcohol-based water absorbent resin, and polyalkylene oxide-based materials. It is preferable to include at least one hydrophilic substance selected from the group consisting of water-absorbing resins.

  According to the artificial soil particle of this configuration, since an appropriate hydrophilic substance is selected as the organic polymer material, it is possible to further increase the initial water absorption of the fiber block. Further, when the organic polymer material enters the fiber mass, the organic polymer material is entangled with the fiber and is in a state of being bonded or in contact with the fiber. For this reason, the water | moisture content supplied by irrigation etc. is reliably delivered to the fiber which comprises a fiber lump through an organic polymer material.

In the artificial soil particles according to the present invention,
The hydrophilizing material is preferably at least one selected from the group consisting of a hydrophilic latex, a surfactant, and a wetting agent.

  According to the artificial soil particle of this configuration, since an appropriate material is selected as the hydrophilizing material, it is possible to further increase the initial water absorption of the fiber block. Further, when the hydrophilizing material comes into contact with the fiber lump, the hydrophilicity of the fiber is improved, and the fiber lump can absorb more water. For this reason, the water | moisture content supplied by irrigation etc. accumulates in the inside of a fiber lump, As a result, the water retention of artificial soil particle improves dramatically.

In the artificial soil particles according to the present invention,
The inorganic porous material is preferably at least one selected from the group consisting of diatomaceous earth, pearlite, vermiculite, zeolite, bentonite, clay, and porous glass beads.

  According to the artificial soil particle of this configuration, since an appropriate material is selected as the inorganic porous material, it is possible to further increase the initial water absorption of the fiber block. In addition, since the inorganic porous material has high hygroscopicity, moisture supplied by irrigation or the like is efficiently absorbed by the inorganic porous material and is reliably received by the fibers constituting the fiber lump through the inorganic porous material. Passed.

In the artificial soil particles according to the present invention,
The fiber is preferably an organic fiber.

  According to the artificial soil particles of this configuration, since relatively soft organic fibers are used as the fibers used for the fiber mass, when the fiber mass is formed, the fibers are intertwined in a complex manner and a large number of voids are formed. As a result, the moisture absorbed in the fiber mass can be retained as water that can be easily used by plants, so-called easy-to-use water. Therefore, plant growth can be promoted even if the number of times of watering or the like is reduced.

In the artificial soil particles according to the present invention,
It is preferable that the water absorption promoting material covers at least a part of the surface of the fiber.

  According to the artificial soil particle of this configuration, since the water absorption promoting material covers at least a part of the surface of the fiber constituting the fiber mass, the water absorption promoting material can directly act on the surface of the fiber. . As a result, the initial water absorption of the fiber lump can be reliably increased, and the water supplied by irrigation or the like can be quickly absorbed into the fiber lump.

In the artificial soil particles according to the present invention,
The volumetric water content at a pF value of 1.5 is preferably 20% or more.

  According to the artificial soil particle of this structure, since the volumetric water content in pF value 1.5 is 20% or more, the water | moisture content required for plant cultivation can fully be hold | maintained in artificial soil particle.

In the artificial soil particles according to the present invention,
The fiber length of the fiber is preferably 0.1 to 2000 μm.

  According to the artificial soil particles of this configuration, the fibers constituting the fiber lump have the optimum fiber length, so that water that can be easily used by plants, so-called easy-to-use water, is reliably retained in the fiber lump. can do.

In the artificial soil particles according to the present invention,
It is preferable that at least a part of the surface of the fiber mass is coated with a water-permeable film.

  According to the artificial soil particle of this configuration, since at least a part of the surface of the fiber lump is covered with the water permeable membrane, it has a certain shielding property while ensuring water permeability between the fiber lump and the external environment. And rigidity can be established.

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 and the absorbed moisture when an organic polymer material is used as the water absorption promoting material. FIG. 3 is a model diagram conceptually showing the relationship between the voids of the artificial soil particles and the absorbed moisture when an inorganic porous material is used as the water absorption promoting material. FIG. 4 is a model diagram conceptually showing the relationship between the voids of the artificial soil particles and the absorbed moisture when both the organic polymer material and the inorganic porous material are used as the water absorption promoting material. FIG. 5 is a schematic diagram of artificial soil particles according to the second embodiment. FIG. 6 is a graph showing changes in the three-phase ratio of the artificial soil medium of the present invention. FIG. 7 is a graph showing changes in the three-phase ratio of the artificial soil medium of the present invention. FIG. 8 is a graph showing changes in the three-phase ratio of the artificial soil medium of the present invention. FIG. 9 is a graph showing changes in the three-phase ratio of the artificial soil culture medium of the comparative example. FIG. 10 is a graph showing changes in the three-phase ratio of the artificial soil culture medium of the present invention using polyethylene glycols having different molecular weights as water absorption promoting materials.

  Hereinafter, the embodiment regarding the artificial soil particle which concerns on this invention is described based on FIGS. However, the present invention is not intended to be limited to the configurations described in the embodiments and drawings described below. Here, the “external environment” described in the present specification intends an environment outside the artificial soil particles. Moisture may be present in the external environment formed between the plurality of artificial soil particles.

<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 into a granular material in which the fibers 1 are intertwined, and there are voids 2 between the fibers 1. The artificial soil particles 50 can absorb and retain moisture in the voids 2 of the fiber lump 10. Since the fiber lump 10 serving as the base of the artificial soil particle 50 has water retention, when the external environment becomes wet, moisture existing in the external environment can be absorbed and retained in the artificial soil particle 50. it can. 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. As a result, the water retentivity of the fiber lump 10 is increased, and the water absorbed by the artificial soil particles 50 can be retained as water that can be easily used by plants, so-called easy water. Therefore, plant growth can be promoted even if the number of times of watering is reduced. 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, and polyethylene fibers. And polyurethane fibers. 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. Therefore, the adsorptivity between the fiber 1 and water can be controlled by adjusting the fiber length of the fiber 1. The fiber length of the fiber 1 is preferably 0.1 to 2000 μm. When the fiber length of the fiber 1 is shorter than 0.1 μm, there is a possibility that sufficient water retention cannot be obtained. On the other hand, if the fiber length of the fiber 1 is longer than 2000 μm, the adsorptivity between the water and the fiber becomes too strong, and there is a possibility that the water that can be used by the plant is reduced.

  Here, once the artificial soil particles are in a dry state, a large amount of air enters the void 2 in the fiber lump 10, so that even if trying to irrigate again, the air gets in the way and the void 2 in the fiber lump 10. As a result, there is a risk that water will be discharged without being sufficiently retained in the fiber lump 10. That is, it may be difficult for artificial soil particles to efficiently absorb moisture from the initial stage of irrigation. Therefore, in the present invention, in order to increase the initial water absorption of the fiber 1 during irrigation, the artificial soil particles contain a water absorption promoting material. The water absorption promoting material includes at least one selected from the group consisting of an organic polymer material and / or a hydrophilizing material, and an inorganic porous material. That is, the water absorption promoting material is configured to include at least one of an organic polymer material, a hydrophilizing material, and an inorganic porous material. Thereby, as for the artificial soil particle 50, the water absorption into the fiber lump 10 is accelerated | stimulated by the effect | action of a water absorption promoting material. Hereinafter, the artificial soil particles 50 containing the water absorption promoting material will be described in detail.

[Artificial soil particles containing organic polymer material and / or hydrophilizing material as water absorption promoting material]
FIG. 2 is a partially enlarged view of the artificial soil particle 50 shown in FIG. 1. When the organic polymer material 3 a is used as the water absorption promoting material 3, the void 2 of the artificial soil particle and the absorbed water W It is the model figure which showed notionally the relationship. In the present embodiment, the case where only the organic polymer material 3a is used as the water absorption promoting material 3 will be described as an example. However, only the hydrophilic material may be used, and the organic polymer material 3a and Both hydrophilizing materials may be used. These three usage patterns can be appropriately selected according to the usage environment of artificial soil particles, the type of plant to be cultivated, and the like. FIG. 2 (a) shows the relationship between the water W immediately after water is supplied by irrigation or the like and the fibers 1 constituting the fiber lump 10, and FIG. 2 (b) is an organic polymer material. FIG. 2C shows a stage where the supplied water W fills the gap 2. When the organic polymer material 3 a is added to the fiber 1 as the water absorption promoting material 3, the organic polymer material 3 a enters the fiber lump 10 and becomes entangled with the fiber 1, and is in a state of being bonded or in contact with the fiber 1. Here, the organic polymer material 3a is selected to have high hydrophilicity. Thereby, as shown to Fig.2 (a), the water | moisture content W supplied by irrigation etc. is adsorb | sucked rapidly. Next, the water W adsorbed on the organic polymer material 3a is quickly delivered to the fiber 1 via the organic polymer material 3a, as shown in FIG. 2 (b), and further to FIG. 2 (c). As shown, it is quickly absorbed and retained in the gap 2. Therefore, even when the irrigation is in the initial stage or when the amount of irrigation is small, the plant can use the water necessary for plant growth. As a result, the number of times of watering the cultivated plant can be reduced, and the labor of the operator can be reduced. In addition, when a hydrophilizing material is used as the water absorption promoting material 3, the fiber 1 is hydrophilized by the hydrophilizing material. As a result, the fiber lump 10 can absorb more moisture, and artificial Water retention of soil particles can be dramatically improved.

  As the organic polymer material 3a, a material having high affinity with the fiber 1 constituting the fiber lump 10 in addition to high hydrophilicity is used. As such an organic polymer material 3a, for example, agar, polyethylene glycol, carrageenan, gelatin, pectin, alginic acid, methylcellulose, carboxymethylcellulose, and salts or derivatives thereof, polyacrylamide-based water absorbent resin, polyvinyl alcohol-based water absorbent resin, Examples include hydrophilic substances such as polyalkylene oxide water-absorbing resins. Of these hydrophilic substances, agar, polyethylene glycol, alginic acid, methylcellulose, carboxymethylcellulose, and salts or derivatives thereof are preferably used. As for polyethylene glycol, those having a molecular weight of 2000 to 20000 are preferable. Examples of alginic acid and salts or derivatives thereof include alginic acid, sodium alginate, potassium alginate, calcium alginate, ammonium alginate, and alginate. The organic polymer material 3a described above can be used in a state where two or more kinds are mixed.

  As in the case of the organic polymer material 3a, a hydrophilic material having high affinity with the fibers 1 constituting the fiber lump 10 is used in addition to high hydrophilicity. Examples of such a hydrophilizing material include a hydrophilic latex, a surfactant, and a wetting agent. Examples of hydrophilic latex include natural latex, polychloroprene latex, styrene-butadiene latex, styrene-butadiene-vinylpyridine latex, acrylonitrile-butadiene latex, carboxyl-modified styrene-butadiene latex, carboxyl-modified styrene-butadiene-vinylpyridine latex, carboxyl Examples include modified acrylonitrile-butadiene latex, carboxyl-modified methyl methacrylate-butadiene latex, acrylate latex, and water-based polyurethane resin. Of these hydrophilic latexes, acrylate latex is preferably used. As the surfactant, for example, an anionic surfactant or a nonionic surfactant can be used. As the wetting agent, for example, alkyl allyl sulfonate and alkyl sulfo succinate can be used. The above hydrophilizing materials can be used in a state where two or more kinds are mixed.

  The amount of the organic polymer material 3a used is related to the water absorption of the fiber lump 10 at the initial stage of irrigation. Therefore, the water absorption of the fiber lump 10 can be controlled by adjusting the amount of the organic polymer material 3a used. In the present invention, when granulating the fiber lump 10, it is preferable to add 0.3 to 20 g of the organic polymer material 3 a to 100 g of the fiber 1. If the addition amount of the organic polymer material 3a is less than 0.3 g with respect to 100 g of the fiber 1, the water absorption of the fiber 1 may not be sufficiently increased. On the other hand, when the addition amount of the organic polymer material 3a exceeds 20 g with respect to 100 g of the fiber 1, the organic polymer material 3a narrows the void 2 in the fiber lump 10 and the artificial soil particles 50 are retained. There is a risk that the performance will be reduced.

  The organic polymer material 3a added to the fiber 1 at the time of granulation is in a state of covering at least a part of the surface of the fiber 1 constituting the fiber lump 10 when the fiber lump 10 is formed. It is desirable. Thereby, the organic polymer material 3a can be directly acted on the surface of the fiber 1, and the moisture adsorbed on the organic polymer material 3a can be reliably delivered to the fiber 1. As a result, the initial water absorption of the artificial soil particles 50 can be reliably increased, and the water supplied by irrigation or the like can be quickly absorbed into the fiber lump 10.

[Artificial soil particles containing an inorganic porous material as a water absorption promoting material]
FIG. 3 is a partially enlarged view of the artificial soil particle 50 shown in FIG. 1. When the inorganic porous material 3 b is used as the water absorption promoting material 3, the voids 2 of the artificial soil particle 50 and the absorbed water are shown. It is the model figure which showed the relationship with W notionally. FIG. 3 (a) shows the relationship between the water W immediately after water is supplied by irrigation or the like and the fibers 1 constituting the fiber lump 10, and FIG. 3 (b) is an inorganic porous material. FIG. 3C shows a stage where the supplied moisture W fills the gap 2. When the inorganic porous material 3 b is added to the fiber 1 as the water absorption promoting material 3, the inorganic porous material 3 b is attached to the surface of the fiber 1 and is in a state of being bonded to or in contact with the fiber 1. Here, as the inorganic porous material 3b, one having high hygroscopicity is selected. Thereby, as shown to Fig.3 (a), the water | moisture content W supplied by irrigation etc. is absorbed rapidly. Next, the absorbed water W is quickly transferred to the fiber 1 through the inorganic porous material 3b as shown in FIG. 3 (b), and further, as shown in FIG. 2 is quickly retained. Therefore, even when the irrigation is in the initial stage or when the amount of irrigation is small, the plant can use the water necessary for plant growth. As a result, the number of times of watering the cultivated plant can be reduced, and the labor of the operator can be reduced.

  As the inorganic porous material 3b, a material having high hygroscopicity is used. For example, porous materials such as diatomaceous earth, perlite, vermiculite, zeolite, bentonite, clay, and porous glass beads are used. Of these porous materials, diatomaceous earth is preferably used. When diatomaceous earth is used as the inorganic porous material 3b, when the fiber lump 10 is granulated, the diatomaceous earth absorbs moisture and becomes viscous. Therefore, it is possible to easily join the fibers 1 that are difficult to adhere to each other. It becomes possible. The inorganic porous material 3b described above can also be used in a state where two or more kinds are mixed.

  The amount of the inorganic porous material 3b used is related to the water absorption of the fiber lump 10 in the initial stage of irrigation. Therefore, the water absorption of the fiber lump 10 can be controlled by adjusting the amount of the inorganic porous material 3b used. In the present invention, when granulating the fiber lump 10, it is preferable to add 20 to 500 g of the inorganic porous material 3 b with respect to 100 g of the fiber 1. If the added amount of the inorganic porous material 3b is less than 20 g with respect to 100 g of the fiber 1, the water absorption of the fiber 1 may not be sufficiently increased. On the other hand, when the added amount of the inorganic porous material 3b exceeds 500 g with respect to 100 g of the fiber 1, the inorganic porous material 3b narrows the void 2 in the fiber lump 10 and the artificial soil particles 50 are retained. There is a risk that the performance will be reduced.

  The inorganic porous material 3b added to the fiber 1 during granulation is preferably in a state of covering at least a part of the surface of the fiber 1 when the fiber lump 10 is formed. Thereby, the inorganic porous material 3b can be made to act directly on the surface of the fiber 1, and the moisture adsorbed on the inorganic porous material 3b can be reliably delivered to the fiber 1. As a result, the initial water absorption of the artificial soil particles 50 can be reliably increased, and the water supplied by irrigation or the like can be quickly absorbed into the fiber lump 10.

[Artificial soil particles containing organic polymer material and / or hydrophilizing material and inorganic porous material as water absorption promoting material]
When designing the artificial soil particles 50, it is effective to include the organic polymer material 3a and / or the hydrophilizing material and the inorganic porous material 3b as the water absorption promoting material 3 in the fiber lump 10. FIG. 4 is a partially enlarged view of the artificial soil particle 50 shown in FIG. 1, and the void of the artificial soil particle 50 when the organic polymer material 3 a and the inorganic porous material 3 b are used as the water absorption promoting material 3. It is the model figure which showed notionally the relationship between 2 and the water | moisture content W absorbed. In this embodiment, the case where the organic polymer material 3a and the inorganic porous material 3b are used as the water absorption promoting material 3 will be described as an example. However, the hydrophilic material and the inorganic porous material 3b are used. Alternatively, the organic polymer material 3a, the hydrophilizing material, and the inorganic porous material 3b may be used. These three usage patterns can be appropriately selected according to the usage environment of artificial soil particles, the type of plant to be cultivated, and the like. FIG. 4A shows the relationship between the water W immediately after water is supplied by irrigation or the like and the fibers 1 constituting the fiber lump 10, and FIG. 4B is the organic polymer material. FIG. 4C shows a stage in which the supplied water W fills the gap 2. FIG. 4C shows a stage in which the fiber 1 is transferred from 3 a and the inorganic porous material 3 b. When the organic polymer material 3a and the inorganic porous material 3b are added to the fiber 1, the inorganic porous material 3b and the fiber 1 are connected via the organic polymer material 3a as shown in FIG. Therefore, both can cooperate and exhibit the synergistic water absorption promotion effect. Since the inorganic porous material 3b has a high affinity with the organic polymer material 3a bonded to or in contact with the fiber 1, water supplied by irrigation or the like as shown in FIG. W is adsorbed quickly in cooperation with the organic polymer material 3a. Next, as shown in FIG. 4B, the moisture W adsorbed on the organic polymer material 3a and the inorganic porous material 3b is quickly transferred to the fiber 1 via the organic polymer material 3a and the inorganic porous material 3b. As shown in FIG. 4C, it is reliably delivered quickly and reliably in the gap 2. Therefore, even in the initial stage of irrigation or when the amount of irrigation is small, the plant can more easily use the water necessary for plant growth. As a result, the number of times of watering the cultivated plant can be reduced, and the labor of the operator can be reduced.

  The usage amount (usage ratio) of the organic polymer material 3a and the inorganic porous material 3b greatly affects the water absorption of the fiber lump 10 at the initial stage of irrigation. Therefore, the water absorption effect of the fiber 1 can be remarkably enhanced by adjusting the respective usage amounts of the organic polymer material 3a and the inorganic porous material 3b. The amount of the inorganic porous material 3b used is preferably 0.9 to 1800 times the weight of the organic polymer material 3a. If the amount of the inorganic porous material 3b used is less than 0.9 times that of the organic polymer material 3a, the synergistic effect of the organic polymer material 3a and the inorganic porous material 3b may not be sufficiently enhanced. is there. On the other hand, even if the amount of the inorganic porous material 3b used exceeds 1800 times that of the organic polymer material 3a, the synergistic effect with the organic polymer material 3a is not improved any more, and problems such as powder falling are rather caused. May occur.

  In order for plants to grow, the soil needs to retain a certain amount of water after irrigation. The force with which the soil retains moisture is expressed as a pF value, and it is necessary to set the volumetric water content at a pF value of 1.5 to a certain level or more. Here, the volumetric water content indicates the amount of water that remains in the soil 24 hours after irrigation of 30 to 50 mm or more per day (a state in which drainage by gravity is almost completed). In order to sufficiently grow plants planted in the soil, the volumetric water content at a pF value of 1.5 is set to 20% or more, preferably 30% or more. If the volumetric water content of the artificial soil medium is set in such a range, the water necessary for plant cultivation can be sufficiently retained in the artificial soil particles 50, so that plant growth can be promoted.

  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, the gap between the artificial soil particles 50 is reduced, and moisture is excessively held by the capillary force of the gap. 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, if the particle size of the artificial soil particles 50 exceeds 10 mm, the gap between the artificial soil particles 50 becomes large and the drainage property becomes excessive, which makes it difficult for the plant to absorb sufficient moisture, There is a possibility that the artificial soil culture medium composed of the particles 50 becomes sparse and the plant falls over. The particle size of the artificial soil particles 50 can be adjusted by sieving.

(Second embodiment)
FIG. 5 is a schematic diagram of artificial soil particles 51 according to the second embodiment. The artificial soil particles 51 are those in which at least a part of the outer surface of the fiber lump 10 constituting the artificial soil particles 50 of the first embodiment is covered with the water membrane 20. The water permeable membrane 20 is a membrane having fine pores through which moisture can pass. Or it can also be set as the permeable membrane which water | moisture content permeates from one side and can move to the other side. The water permeable membrane 20 functions to establish a certain shielding property and rigidity while ensuring water permeability between the fiber lump 10 and the external environment. For this reason, it becomes possible to adjust the water retention and water absorption of the artificial soil particles 51 also by changing the film thickness and material of the water permeable membrane 20. Since the water permeable membrane 20 can take in moisture from the external environment and release moisture to the external environment, the artificial soil particles 51 provided with the water permeable membrane 20 accompany movement of moisture such as artificial soil. Excellent flexibility can be shown in the application.

  Moreover, the strength of the artificial soil particles 51 is maintained and the durability is improved by covering the fiber lump 10 with the aqueous film 20. Therefore, by covering the outer surface of the fiber lump 10 with the water membrane 20, both water retention and strength can be achieved. 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, and examples thereof include a resin material. Examples of such a resin material include polyolefin resins such as polyethylene and polypropylene, vinyl chloride resins such as polyvinyl chloride and polyvinylidene chloride, polyester resins such as polyethylene terephthalate, and styrene resins such as polystyrene. Of these, polyethylene is preferred. In place of the resin material, a synthetic polymer gelling agent such as polyethylene glycol or a natural gelling agent such as sodium alginate can be used.

<Method for producing artificial soil particles>
The manufacturing method of the artificial soil particle 50 of 1st embodiment is demonstrated. When the organic polymer material 3a is used as the water absorption promoting material 3, first, a predetermined amount of the fiber 1 is stirred with a stirring and mixing granulator, and a granulation liquid in which the organic polymer material 3a is added to the binder is added little by little. And granulate. Thereby, the organic polymer material 3 a adheres to the surface of the fiber 1. The same operation is performed when a hydrophilic material is used as the water absorption promoting material 3 or when both the organic polymer material 3a and the hydrophilic material are used. Examples of usable binders include polyolefin resins, polyvinyl alcohol resins, polyurethane resins, polyvinyl acetate resins, and latexes. When the inorganic porous material 3b is used as the water absorption promoting material 3, the inorganic porous material 3b is put into the stirring and mixing granulator together with the fibers 1, and stirred and mixed until uniform, and then granulated while stirring. Add a small amount of liquid and granulate. When the organic polymer material 3a and the inorganic porous material 3b are used, a granulated product in which the organic polymer material 3a and the inorganic porous material 3b are attached to the surface of the fiber 1 can be obtained. When the granulated product of the fiber 1 is dried with a dryer, at least a part of the surface of the fiber 1 is covered with the organic polymer material 3a and / or the inorganic porous material 3b. Next, the temperature of the dryer is raised, and the binder 1 dispersed in the granulated material is melted to fix the fibers 1 to each other. Thereby, the fiber lump 10 is completed and can be used as the artificial soil particle 50 shown in FIG. A solid (powder) binder is put into a stirring and mixing granulator together with fibers 1 and stirred and mixed until uniform, and then a liquid containing the water absorption promoting material 3 is added little by little to form a fiber lump. It is also possible to finish the body 10. The artificial soil particles 50 are dried and classified as necessary to adjust the particle size.

  When granulating the fiber lump 10, if diatomaceous earth is used as the inorganic porous material 3 b, the particle size distribution of the fiber lump 10 to be granulated can be easily adjusted. Since diatomaceous earth becomes viscous by absorbing moisture, the fibers 1 that are difficult to adhere can be easily bonded to each other by moisture added during granulation. By utilizing the characteristics of this diatomaceous earth and further adjusting the rotation speed of the stirring blade of the stirring and mixing granulator and the dripping amount of the binder, it is possible to easily produce the fiber lump 10 having a desired particle size distribution. become.

  The artificial soil particles 51 of the second embodiment are obtained by forming the water permeable membrane 20 on the surface of the fiber block 10 constituting the artificial soil particles 50 of the first embodiment. For example, the case where a polyethylene emulsion is used as the resin material will be described as an example. 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 fiber lump 10 to which the polyethylene emulsion is adhered is dried with a dryer, and then the dryer is heated to melt the polyethylene, and the polyethylene is fused to the fibers 1 near the outer surface of the fiber lump 10. A water permeable membrane 20 is formed. 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, water permeability between the fiber lump 10 and the external environment is ensured. The obtained 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 water retention characteristics were evaluated. In this example, the water retention characteristics of the artificial soil medium were evaluated from the change in the three-phase distribution of the artificial soil medium depending on the number of irrigations.

[Preparation of artificial soil medium]
Artificial soil particles were prepared according to the blending amount (g) described in Table 1.
<Example 1>
As organic fiber, 600 g of cellulose fiber (BWW 40, average fiber length 0.2 mm, average fiber diameter 0.02 mm, manufactured by Rettenmeier) is used, and this is stirred and rolled by a stirring and mixing granulator (manufactured by G-Labo Co., Ltd.). While moving, 1200 g of granulation liquid was added and granulated to form a fiber mass in which the granulation liquid was impregnated. The granulation liquid was prepared according to the blending amounts shown in Table 1, (1) polyolefin resin emulsion (Sumitomo Seika Co., Ltd., Sepoljon G315, concentration 40% by weight) as a binder, and (2) water absorption promoter (organic high Molecular material) was mixed with an agar aqueous solution (manufactured by Nacalai Tesque Co., Ltd., final concentration of granulation liquid: 0.5% by weight). Next, 25 g of polyolefin resin emulsion was added to the fiber mass, and impregnated while rolling so that the emulsion adhered uniformly to the outer surface of the fiber mass. The fiber lump is dried at 60 ° C. using a dryer, and the surface of the cellulose fiber is coated with agar, and then the dryer is heated to 100 ° C. to melt the polyolefin resin to fix the cellulose fibers together. Artificial soil particles with a water permeable membrane were prepared.

<Example 2>
Cellulose fiber 300g which is an organic fiber and diatomaceous earth (Radiolite (registered trademark) 300, manufactured by Showa Chemical Industry Co., Ltd.) 300g which is a water absorption promoting material (inorganic porous material) are put into a stirring and mixing granulator, and uniformly While stirring and rolling until it becomes, 820 g of granulation liquid was added and granulated to form a fiber mass impregnated with the granulation liquid. The granulating liquid was prepared by mixing (1) a polyolefin resin emulsion and (2) water in accordance with the blending amounts shown in Table 1. The fiber lump is dried at 60 ° C. using a dryer, and the surface of the cellulose fiber is coated with agar, and then the dryer is heated to 100 ° C. to melt the polyolefin resin to fix the cellulose fibers together. Artificial soil particles were prepared.

<Example 3>
Cellulose fiber 300g which is organic fiber and diatomaceous earth 300g which is water absorption promoting material (inorganic porous material) are put into a stirring and mixing granulator, and 844g of granulating liquid is added while stirring and rolling until uniform. Granulated and formed into a fiber lump with the granulation liquid impregnated inside. The granulation liquid was prepared by mixing (1) a polyolefin resin emulsion and (2) an agar aqueous solution which is a water absorption promoting material (organic polymer material) according to the blending amount shown in Table 1. The fiber lump is dried at 60 ° C. using a dryer, and the surface of the cellulose fiber is coated with agar, then heated to 100 ° C. to melt the polyolefin resin, and the cellulose fibers are fixed together to artificial soil. Particles were made.

<Example 4>
Cellulose fiber 300g which is organic fiber and diatomaceous earth 300g which is water absorption promoting material (inorganic porous material) are put into a stirring and mixing granulator, and 844g of granulating liquid is added while stirring and rolling until uniform. Granulated and formed into a fiber lump with the granulation liquid impregnated inside. The granulation liquid was prepared by mixing (1) a polyolefin resin emulsion and (2) an agar aqueous solution which is a water absorption promoting material (organic polymer material) according to the blending amount shown in Table 1. The fiber lump is dried at 60 ° C. using a dryer, and the surface of the cellulose fiber is coated with agar, then heated to 100 ° C. to melt the polyolefin resin, and the cellulose fibers are fixed together to artificial soil. Particles were made.

<Example 5>
Cellulose fiber 400g which is an organic fiber, diatomaceous earth 200g which is a water absorption promoting material (inorganic porous material), and foamed glass (Supersol (registered trademark), manufactured by Trim Co., Ltd.) 100g are put into a stirring and mixing granulator. While stirring and rolling until uniform, 1170 g of granulation liquid was added and granulated to form a fiber lump body impregnated with the granulation liquid. The granulation liquid was prepared by mixing (1) a polyolefin resin emulsion and (2) an agar aqueous solution which is a water absorption promoting material (organic polymer material) according to the blending amount shown in Table 1. Next, 25 g of polyolefin resin emulsion was added to the fiber mass, and impregnated while rolling so that the emulsion adhered uniformly to the outer surface of the fiber mass. The fiber lump is dried at 60 ° C. using a dryer, and the surface of the cellulose fiber is coated with agar, and then the dryer is heated to 100 ° C. to melt the polyolefin resin to fix the cellulose fibers together. Artificial soil particles with a water permeable membrane were prepared.

<Example 6>
Cellulose fiber 150g which is organic fiber and diatomaceous earth 550g which is water absorption promoting material (inorganic porous material) are put into a stirring and mixing granulator, and 1045g of granulating liquid is added while stirring and rolling until uniform. Granulated and formed into a fiber lump with the granulation liquid impregnated inside. The granulation liquid was prepared according to the blending amounts shown in Table 1, (1) polyolefin resin emulsion, (2) agar and polyethylene glycol (molecular weight: 2000, manufactured by Nacalai Tesque Co., Ltd.) as a water absorption promoting material (organic polymer material). ) Containing aqueous solution. The fiber mass is dried at 60 ° C. using a dryer, and the surface of the cellulose fiber is coated with agar and polyethylene glycol, and then heated to 100 ° C. to melt the polyolefin-based resin, thereby fixing the cellulose fibers together. Artificial soil particles were prepared.

<Example 7>
Cellulose fiber 300g which is organic fiber and 180g of diatomaceous earth which is water absorption promoting material (inorganic porous material) are put into a stirring and mixing granulator, and 834g of granulating liquid is added while stirring and rolling until uniform. Granulated and formed into a fiber lump with the granulation liquid impregnated inside. In accordance with the blending amount shown in Table 1, the granulation liquid was prepared by mixing (1) a polyolefin resin emulsion and (2) a potassium alginate aqueous solution (made by Kimika Co., Ltd.), which is a water absorption promoting material (organic polymer material). It was supposed to be. The fiber lump is dried at 60 ° C. using a dryer, and the surface of the cellulose fiber is coated with potassium alginate, and then heated to 100 ° C. to melt the polyolefin-based resin, thereby fixing the cellulose fibers together to artificially Soil particles were made.

<Example 8>
200g of organic fibers and 100g of polyester fibers (average fiber length 0.5mm, manufactured by Kuraray Co., Ltd.) are put into a stirring and mixing granulator, and stirred and rolled until uniform, 1155g of granulating liquid. Was added and granulated to form a fiber mass in which the granulation liquid was impregnated. The granulation liquid was prepared by mixing (1) a polyolefin resin emulsion and (2) an agar aqueous solution which is a water absorption promoting material (organic polymer material) according to the blending amount shown in Table 1. Next, 20 g of a polyolefin resin emulsion was added to the fiber mass, and impregnated while rolling so that the emulsion adhered uniformly to the outer surface of the fiber mass. The fiber lump is dried at 60 ° C. using a dryer, and the surface of the cellulose fiber is coated with agar, and then the dryer is heated to 100 ° C. to melt the polyolefin resin to fix the cellulose fibers together. Artificial soil particles with a water permeable membrane were prepared.

<Example 9>
200 g of polyester fibers as organic fibers and 350 g of diatomaceous earth as a water absorption promoting material (inorganic porous material) are put into a stirring and mixing granulator, and 1655 g of granulating liquid is added while stirring and rolling until uniform. Granulated and formed into a fiber lump with the granulation liquid impregnated inside. The granulating liquid comprises (1) a polyolefin resin emulsion, (2) agar as a water absorption promoting material (organic polymer material), polyethylene glycol (molecular weight: 2000), and potassium alginate according to the blending amounts shown in Table 1. The aqueous solution containing it was mixed. The fiber mass is dried at 60 ° C. using a dryer, and the surface of the cellulose fiber is coated with agar, polyethylene glycol, and potassium alginate, and then heated to 100 ° C. to melt the polyolefin-based resin. Artificial soil particles were prepared by fixing them together.

<Example 10>
As a water absorption promoting material (organic polymer material), an aqueous polyethylene glycol solution (molecular weight: 2000, manufactured by Nacalai Tesque, Inc., final concentration of granulation liquid: 0.5% by weight) is used instead of the agar aqueous solution of Example 1. did. Other than that, the artificial soil particle which has a water-permeable film by the method similar to Example 1 was produced.

<Example 11>
As a water absorption promoting material (organic polymer material), an aqueous polyethylene glycol solution (molecular weight: 6000, manufactured by Nacalai Tesque, Inc., final concentration of granulation liquid: 0.5% by weight) is used instead of the agar aqueous solution of Example 1. did. Other than that, the artificial soil particle which has a water-permeable film by the method similar to Example 1 was produced.

<Example 12>
As a water absorption promoting material (organic polymer material), an aqueous polyethylene glycol solution (molecular weight: 20000, manufactured by Nacalai Tesque, Inc., final concentration of granulation liquid: 0.5% by weight) is used instead of the agar aqueous solution of Example 1. did. Other than that, the artificial soil particle which has a water-permeable film by the method similar to Example 1 was produced.

<Comparative Example 1>
Artificial soil particles having a water-permeable membrane were produced in the same manner as in Example 1 using a granulating liquid that did not contain a water absorption promoting material.

  Each artificial soil particle of Examples 1 to 12 and Comparative Example 1 was adjusted to a particle size of 2 to 4 mm by sieving, and this was used as an artificial soil medium for use in an evaluation test of moisture retention characteristics.

[Evaluation of water retention characteristics of artificial soil medium]
100cc of each artificial soil medium with a moisture content of 5% by weight or less is put into a stainless steel cup (diameter 50mm x height 51mm, capacity 100cc) provided with a number of drain holes with a diameter of about 1mm on the bottom. This was subjected to the test. As a test method, 50 ml of water (100 ml in the comparative example) was dropped on each artificial soil medium, the change in the weight of the sample was measured, and the solid phase ratio, liquid phase ratio, and gas phase ratio of each artificial soil medium were measured. The phase distribution was calculated. And the said water dripping and calculation of three phase distribution were repeatedly implemented until the value of the liquid phase rate of each artificial soil culture medium became fixed. About a moisture content and a solid-phase rate, it measured with the following method.
(1) Moisture content: Measured using an infrared heating dry mass measurement type moisture content meter (model number: MOC-120H, manufactured by Shimadzu Corporation). As measurement conditions, the sample amount of each artificial soil medium was set to about 3 to 6 g, and the heating temperature was set to 120 ° C.
(2) Solid-phase ratio: About each artificial soil culture medium 100cc before dripping water, it measured using the digital real volume measuring apparatus (model number: DIK-1150, Dairika Kogyo Co., Ltd. make).

  6 to 8 are graphs showing changes in the three-phase ratio of the artificial soil medium of the present invention. 6 evaluated the artificial soil culture medium of Example 1, Example 2, and Example 3, and FIG. 7 evaluated the artificial soil culture medium of Example 4, Example 5, and Example 6. FIG. FIG. 8 shows an evaluation of the artificial soil culture media of Example 7, Example 8, and Example 9. FIG. 9 is a graph showing changes in the three-phase ratio of the artificial soil culture medium of the comparative example. The artificial soil medium of Example 1 using agar as the water absorption promoting material reached a substantially constant liquid phase ratio (corresponding to the volumetric water content at a pF value of 1.5) by the second drop of water, and was very Showed high water absorption. The artificial soil medium of Example 2 using diatomaceous earth as a water absorption promoting material reached a substantially constant liquid phase ratio by the third drop of water, and also showed high water absorption from the initial stage. The artificial soil culture medium of Example 3 using a combination of agar as an organic polymer material and diatomaceous earth as an inorganic porous material as a water absorption promoting material reaches a substantially constant liquid phase ratio by the first drop of water, and the initial stage. The water absorption was extremely high. The results of Example 3 are clearly superior in water absorption at the initial stage as compared with the artificial soil culture media of Examples 1 and 2, and the synergistic effect of the agar that is an organic polymer material and diatomaceous earth that is an inorganic porous material. confirmed. The artificial soil medium of Example 4 is obtained by reducing the amount of agar added to the artificial soil particles of Example 3 to half or less, and exhibits high water absorption from the initial stage, and is an organic polymer material agar. A synergistic effect with diatomaceous earth, which is an inorganic porous material, was confirmed. The artificial soil medium of Example 5 to which foamed glass was added as an inorganic porous material, the artificial soil medium of Example 6 to which polyethylene glycol was added as an organic polymer material, and Example 7 to which potassium alginate was added as an organic polymer material These artificial soil culture media showed high water absorption, indicating that these water absorption promoting materials are effective in improving the initial water absorption of the artificial soil culture media. Moreover, although the artificial soil culture medium of Example 8 and Example 9 uses the polyester fiber which is a synthetic organic fiber for some or all of the fiber used for a fiber lump, all are the water of the 3rd time. It was confirmed that a substantially constant liquid phase ratio was reached by dropping, and that even when synthetic organic fibers were used as the fibers, high water absorption was exhibited from the initial stage. On the other hand, the artificial soil culture medium of Comparative Example 1 that does not contain a water absorption promoting material, until the dripping amount of water is increased to 100 ml (50 ml in the example), reaches a substantially constant liquid phase rate. This required 5 drops of water, and the water absorption at the initial stage was insufficient.

  FIG. 10 is a graph showing changes in the three-phase ratio of the artificial soil culture medium of the present invention using polyethylene glycol having different molecular weights as a water absorption promoting material. The artificial soil culture medium of Example 10 (molecular weight of PEG: 2000), The artificial soil culture medium of Example 11 (PEG molecular weight: 6000) and the artificial soil culture medium of Example 12 (PEG molecular weight: 20000) were evaluated. The artificial soil culture media of Examples 10 to 12 all reached a substantially constant liquid phase ratio by the third drop of water. Even when polyethylene glycol having a different molecular weight was used as the water absorption promoting material, it was confirmed that high water absorption was exhibited from the initial stage.

  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 Water absorption promotion material 3a Organic polymer material 3b Inorganic porous material 10 Fiber aggregate 20 Water-permeable membrane 50,51 Artificial soil particle

Claims (10)

Artificial soil particles having a fiber mass formed by granulating fibers,
Artificial soil particles containing a water absorption promoting material that enhances the initial water absorption of the fiber mass.   The artificial soil particle according to claim 1, wherein the water absorption promoting material includes at least one selected from the group consisting of an organic polymer material and / or a hydrophilizing material, and an inorganic porous material.   The organic polymer material includes agar, polyethylene glycol, carrageenan, gelatin, pectin, alginic acid, methylcellulose, carboxymethylcellulose, and salts or derivatives thereof, polyacrylamide-based water absorbent resin, polyvinyl alcohol-based water absorbent resin, and polyalkylene oxide-based materials. The artificial soil particle according to claim 2, comprising at least one hydrophilic substance selected from the group consisting of a water absorbent resin.   The artificial soil particle according to claim 2 or 3, wherein the hydrophilizing material includes at least one selected from the group consisting of a hydrophilic latex, a surfactant, and a wetting agent.   The artificial inorganic material according to any one of claims 2 to 4, wherein the inorganic porous material is at least one selected from the group consisting of diatomaceous earth, pearlite, vermiculite, zeolite, bentonite, clay, and porous glass beads. Soil particles.   The artificial fiber according to any one of claims 1 to 5, wherein the fiber is an organic fiber.   The artificial soil particle according to any one of claims 1 to 6, wherein the water absorption promoting material covers at least a part of a surface of the fiber.   The artificial soil particles according to any one of claims 1 to 7, wherein the volumetric water content at a pF value of 1.5 is 20% or more.   The fiber length of the said fiber is 0.1-2000 micrometers, The artificial soil particle as described in any one of Claims 1-8.   The artificial soil particle according to any one of claims 1 to 9, wherein at least a part of the surface of the fiber mass is coated with a water-permeable film.

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