JP2017079687A - Artificial soil particles and artificial soil medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide artificial soil particles having high durability and water resistance, easy handling, and excellent aesthetic appearance while maintaining basic performance as soil.SOLUTION: An artificial soil particle 100 containing inorganic matter and organic matter are provided with a mixed granular body 50 obtained by mixing an inorganic filler 10, an organic fiber 20, and a resin 30 into granules. The mixed granular body 50 has a first region A in which a resin 30 is mainly present and a second region B in which the inorganic filler 10 and the organic fiber 20 are mainly present. In the cross-sectional view of the mixed granular body 50, the first region A is constituted by a plurality of island-shaped parts having an average size of 10-700 μm. The cross-sectional area of the first region A with respect to the total cross-sectional area of the mixed granular body 50 is 5-60%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an artificial soil particle provided with a mixed granule containing an inorganic filler, an organic fiber, and a resin, and an artificial soil medium.

  Artificial soil has been used to grow vegetables in plant factories, but in recent years, the needs for artificial soil have diversified. For example, artificial soil is used to cultivate various plants such as foliage plants and flower buds. It has come to be. Artificial soil is required not only to have excellent basic performance (water retention, fertilizer retention, etc.), but also to have a clean feeling and easy handling. For example, products that put artificial soil in transparent or translucent pots and cultivate foliage plants indoors have been developed, but such highly interior products are not only beautiful in appearance and clean, Water resistance, durability, and ease of handling are required. However, since foliage plants and potted flower buds are not supposed to basically replace the soil once they are used, the structure of the artificial soil is affected by changes in the water environment due to irrigation, changes in the temperature environment, etc. It may gradually disintegrate and it may be difficult to maintain performance such as water retention, fertilizer retention, water resistance, and durability over a long period of time. In addition, when white organic matter such as cellulose fiber is used as a raw material for artificial soil, there is a concern that the artificial soil will turn brown when the period of use is prolonged, and the product value may be deteriorated due to loss of aesthetics and cleanliness. It was.

  As artificial soil developed so far, there was a porous artificial soil body in which at least one component of organic matter, inorganic matter, and soil, and solid matter such as gypsum were combined with a cured product of water-soluble urethane polymer (for example, , See Patent Document 1). The porous artificial soil body of Patent Document 1 is obtained by improving the water retention of the artificial soil body by forming pores capable of holding water by partially combining solid substances.

  Moreover, there was a aggregated structure zeolite in which powdery zeolite was bound by a binder made of a water-soluble polymer (see, for example, Patent Document 2). The aggregate structure zeolite of Patent Document 2 is a structure in which zeolite is aggregated to form pores capable of retaining water, thereby increasing the water retention of the aggregate.

JP-A-5-244820 JP 2000-336356 A

  In the artificial soil used for cultivation of ornamental plants and potted flower buds, etc., it is natural that it has basic performance such as water retention and fertilization, and it has excellent aesthetics and high water resistance and durability. And it is desired that handling is easy. In this respect, the artificial soil body of Patent Document 1 cannot be said to have sufficient strength because the bonding form of the cured product of the water-soluble urethane polymer is partial. For this reason, the structure of the artificial soil body is destroyed by a change in the moisture environment or the temperature environment, and as a result, the basic performance as soil may be reduced, or fine powder may be generated and difficult to handle. Patent Document 1 includes dark colored solids such as red soil, black soil, sludge, and old tire powder as raw materials for artificial soil bodies. However, artificial soil bodies using these as raw materials are brown. Because it presents, it cannot be said that it has an aesthetic suitable for indoor cultivation where interior properties are required.

  The aggregated structure zeolite of Patent Document 2 is obtained by simply mixing a powdered zeolite and a binder in the presence of water and drying them, so it can be said that the bonding force between the zeolite particles is sufficient. Absent. When planting plants such as foliage plants using this aggregate structure zeolite, the aggregate structure is destroyed by external pressure, etc., water retention and fertilizer retention is reduced, fine powder etc. are generated and handled May be difficult.

  The present invention has been made in view of the above problems, has high durability and water resistance while maintaining basic performance as soil, is easy to handle, and is also excellent in aesthetics. An object is to provide artificial soil particles and an artificial soil medium.

The characteristic configuration of the artificial soil particles according to the present invention for solving the above problems is as follows:
Artificial soil particles comprising a mixed granule containing inorganic filler, organic fiber, and resin,
The mixed granule has a first region mainly containing the resin, and a second region mainly containing the inorganic filler and the organic fiber,
In the cross-sectional view of the mixed granular material, the first region is composed of a plurality of island portions having an average size of 10 to 700 μm, and the cross-sectional area of the first region with respect to the total cross-sectional area of the mixed granular material is 5 to 60. It is to be%.

According to the artificial soil particle of this structure, the mixed granular material containing an inorganic filler, organic fiber, and resin is made into the artificial soil particle. Since the resin contained in the mixed granule is excellent in water resistance and durability, the shape of the artificial soil particle is not destroyed even if the artificial soil particle is exposed to a moist environment for a long time. Can be maintained. Further, the mixed granular body has a first region mainly containing a resin and a second region mainly containing an inorganic filler and an organic fiber, and the resin, the inorganic filler and the organic fiber are completely mixed. Since it is not in a state, the water resistance and durability derived from the resin and the water retention and fertilizer retention derived from the inorganic filler and the organic fiber can be exhibited in a balanced manner. Moreover, in the cross-sectional view of the mixed granular material, the first region is composed of a plurality of island-shaped portions having an average size of 10 to 700 μm, and the cross-sectional area of the first region with respect to the total cross-sectional area of the mixed granular material is 5 to 60%. Therefore, even if the artificial soil particles are exposed to a moist environment for a long time, the structure of the artificial soil particles is not destroyed and it is easy to use, while maintaining its shape, water retention and fertilizer retention Etc. can exhibit the basic performance.
In this way, the artificial soil particles of this configuration are easy to handle without degrading the basic performance as soil, and are excellent in usability, and are used for houseplants and potted plants with little exchange of soil. It can be suitably used as a culture medium for florets and the like.

In the artificial soil particles according to the present invention,
In the mixed granular material, the total amount (a) of the inorganic filler and the organic fiber and the amount (b) of the resin are 2: 1 to 30: 1 in a weight ratio (a: b). It is preferable that it is set.

  According to the artificial soil particles of this configuration, the total blending amount (a) of the inorganic filler and the organic fiber and the blending amount (b) of the non-emulsion binder are set to the appropriate weight ratio (a: b). Therefore, in particular, water resistance and durability can be enhanced while sufficiently maintaining water retention, which is one of the basic performances of artificial soil particles.

In the artificial soil particles according to the present invention,
The resin is derived from a resin powder having a 50% particle size range of 15 to 355 μm and a melt flow rate (temperature: 190 ° C., load: 2.16 kgf) measured in accordance with JIS K7210 of 50 g / 10 min or more. It is preferable to do.

  According to the artificial soil particle of this structure, since the resin derived from the resin powder having the above appropriate particle size range is included, discoloration due to deterioration with time of the inorganic filler and the organic fiber can be minimized. In addition, since the resin powder has the appropriate melt flow rate described above, it can effectively increase the bonding strength between the inorganic filler and the organic fiber, and is excellent in water resistance and durability while maintaining the basic performance as soil. Artificial soil particles.

In the artificial soil particles according to the present invention,
The resin powder is preferably a polyolefin resin powder.

  According to the artificial soil particle of this structure, it can be set as the artificial soil particle excellent in water resistance and durability especially by selecting polyolefin resin powder as resin powder.

In the artificial soil particles according to the present invention,
The inorganic filler is preferably white diatomaceous earth, and the organic fiber is preferably cellulose.

  According to the artificial soil particle of this structure, since the white diatomaceous earth used as an inorganic filler and the cellulose used as an organic fiber are all white-type materials, they can be artificial soil particles excellent in aesthetics.

In the artificial soil particles according to the present invention,
The mixed granule preferably contains a colorant and / or a discoloration preventing agent.

  According to the artificial soil particle of this structure, since the mixed granular material containing the inorganic filler, the organic fiber, and the resin further includes the colorant and / or the discoloration preventing agent, the artificial soil particle having excellent interior properties can be obtained. . In particular, when the inorganic filler and the organic fiber are white materials, the coloring by the coloring agent becomes vivid, and when the anti-discoloring agent is included, the discoloration due to deterioration with time is prevented, thereby adding value. Can be increased.

In the artificial soil particles according to the present invention,
It is preferable that the surface of the mixed granular material is coated with a discoloration inhibitor.

  According to the artificial soil particles of this configuration, discoloration of the artificial soil particles is prevented by the anti-discoloring agent, and therefore, it is suitably used as a growth medium for indoor houseplants and potted flower buds that require aesthetics and cleanliness. be able to.

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

  According to the artificial soil medium of this configuration, the same excellent effects as those of the artificial soil particles described above are exhibited. That is, the water resistance and durability derived from the resin and the water retention and fertilizer retention derived from the inorganic filler and organic fiber can be exerted in a balanced manner, and the artificial soil particles are exposed to a moist environment for a long period of time. Even if this is done, the structure of the artificial soil particles is not destroyed and it is easy to use. And basic performances, such as water retention and fertilizer retention, can be exhibited, maintaining the shape of artificial soil particles.

In the artificial soil medium according to the present invention,
It is preferable that the particle size distribution of the artificial soil particles is adjusted to 0.5 to 12 mm.

  According to the artificial soil culture medium of this configuration, since the particle size distribution is adjusted to the appropriate range described above, it is possible to hold an appropriate amount of water in the gap between the artificial soil particles, and to improve water retention. it can.

In the artificial soil medium according to the present invention,
A growth medium for florets or foliage plants is preferred.

  According to the artificial soil culture medium of this configuration, it is easy to handle without degrading the basic performance as soil, and it is also easy to use. Can be suitably used as a growth medium.

FIG. 1 is a schematic configuration diagram of artificial soil particles of the present invention. FIG. 2 is a flowchart showing a procedure for producing the artificial soil particles of the present invention. FIG. 3 is a microscopic image of the artificial soil particles according to the example.

  Embodiments of the present invention will be described below with reference to FIGS. However, the present invention is not intended to be limited to the configurations described in the following description and drawings.

<Artificial soil particles>
FIG. 1 is a schematic configuration diagram of an artificial soil particle 100 of the present invention. FIG. 1A is a diagram schematically illustrating the entire artificial soil particle 100, and FIG. 1B is a diagram in which the inside of the artificial soil particle 100 is partially enlarged. The artificial soil particle 100 includes a mixed granular material (cured granulated product) 50 including an inorganic filler 10, an organic fiber 20, and a resin 30. The mixed granular material 50 is configured by mixing and granulating the inorganic filler 10, the organic fiber 20, and the resin 30. The inorganic filler 10 and the organic fiber 20 contained in the artificial soil particle 100 exist in the artificial soil particle 100 in a state of being mixed with each other, and are fixed through the resin 30 while maintaining the state. Thus, the artificial soil particles 100 are maintained in the shape of particles by the resin 30. Hereinafter, the structure of the artificial soil particle 100 of this invention is demonstrated.

  Although the inorganic filler 10 will not be specifically limited if it is an inorganic substance, It is preferable that it is inorganic porous bodies, such as a porous mineral, an inorganic foam, an inorganic porous aggregate. Examples of the porous mineral include diatomaceous earth, perlite, vermiculite, and pumice. Examples of the inorganic foam include glass foam, shale foam, and shirasu balloon. Examples of the inorganic porous aggregate include foamed concrete and foamed brick. Among these inorganic porous bodies, diatomaceous earth and pearlite, which are porous minerals, are excellent in water retention, have a good appearance because they have a white appearance, have good colorability, and are inexpensive. Since it is also inexpensive, it is particularly preferably used as a material for artificial soil used in large quantities. When it is desired to increase the fertilizer of the artificial soil particle 100, a mineral having ion exchange ability can be used as the inorganic filler 10. Examples of the inorganic filler 10 include cation exchange minerals (eg, smectite minerals such as montmorillonite, bentonite, beidellite, hectorite, saponite, and stevensite, mica minerals, vermiculite, and zeolite), anion exchange minerals ( For example, natural layered double hydroxides with double hydroxide as the main skeleton such as hydrotalcite, manaceite, pyroaulite, sjoglenite, patina, synthetic hydrotalcite and hydrotalcite-like substances, allophane, imogolite, kaolin And clay minerals). Each inorganic filler 10 listed above may be a mixture of two or more. For example, if diatomaceous earth and zeolite are selected as the inorganic filler 10 and mixed with an appropriate blending ratio, artificial soil particles that have both water retention and fertilizer retention while being relatively inexpensive. 100 can be designed.

  The organic fiber 20 is not particularly limited as long as it is an organic material, and naturally-derived fibers, regenerated fibers, semi-synthetic fibers, synthetic fibers, and the like can be used. However, it is preferable to use hydrophilic fibers so that the artificial soil particles 100 can maintain a certain level of water retention. Preferred hydrophilic fibers include cellulose, cotton, wool, and the like for natural fibers, rayon and the like for regenerated fibers, acetate for semisynthetic fibers, and vinylon, urethane, and nylon for synthetic fibers. Among these hydrophilic fibers, cellulose, cotton, and vinylon have a white appearance and have good appearance, good coloration, and are inexpensive in price. Particularly preferably used as a material. The organic fiber 20 may be a mixture of a plurality of types of fibers.

  The resin 30 is derived from the non-emulsion binder, which is one of the raw materials of the artificial soil particles 100, and is formed in the mixed granular material 50. In the curing step of “Artificial soil particle manufacturing method” described later, The non-emulsion binder is solidified. For example, the resin 30 is formed by melting and solidifying a resin powder made of a polyolefin resin such as polyethylene resin (PE) or low-density polyethylene resin (LDPE) in the mixed granule 50. Therefore, the resin 30 contains the non-emulsion binder component as it is. The non-emulsion binder has a 50% particle size range of 15 to 355 μm, preferably 75 to 180 μm, and a melt flow rate (temperature: 190 ° C., load: 2.16 kgf) measured according to JIS K7210 is 50 g / A resin powder of 10 minutes or more, preferably 58 g / 10 minutes or more is used. If the resin powder having such properties is used, discoloration or fading of artificial soil particles that may occur due to deterioration of the inorganic filler or organic fiber with time can be minimized. Moreover, if the resin powder which has said appropriate melt flow rate is used, the bond strength of an inorganic filler and organic fiber can be improved effectively, and the basic performance of the artificial soil particle 100 finally obtained will be maintained. However, water resistance and durability can be improved.

  As shown in the partially enlarged view of FIG. 1B, the resin 30 is dispersed in an island shape inside the mixed granular material 50. In this specification, the area | region where the resin 30 mainly exists in the mixed granular material 50 is made into the 1st area | region A, and the area | region where the inorganic filler 10 and the organic fiber 20 mainly exist is prescribed | regulated as the 2nd area | region B. The artificial soil particle 100 adjusts characteristics such as water retention, water resistance and durability by changing the size of the first region A in the mixed granule 50 and the ratio of the first region A and the second region B. can do. According to the study by the present inventors, when designing the artificial soil particles 100, the average size of the first region A is set to 10 to 700 μm, preferably 80 to 450 μm, and mixed as shown in the examples described later. The cross-sectional area of the first region A with respect to the total cross-sectional area of the granule 50 (total cross-sectional area of the first region A and the second region B) is 5 to 60%, preferably 7 to 50%, more preferably 10 to 30. By setting the%, even if the artificial soil particles 100 are exposed to a moist environment for a long time, high durability and water resistance are maintained while maintaining the basic performance (water retention, fertilizer retention, etc.) as soil. It turns out that it can be realized.

  Here, the average size of the first regions A is, for example, the area of each first region A with respect to the plurality of first regions A appearing in the observation region when the surface or the inside of the mixed granular material 50 is observed with a microscope or the like. Is converted into a plurality of equivalent circles and is obtained from the average diameter of the circles. That is, the average diameter of the equivalent circles of the first region A can be regarded as the average size of the first region A.

  The cross-sectional area of the first region A relative to the total cross-sectional area of the mixed granular material 50 can be obtained, for example, by the following image analysis. The surface or the inside of the mixed granular material 50 is observed with a microscope or the like, and an image of the observation region is acquired. The acquired image is divided into a plurality of meshes. For each mesh, (a) a mesh mainly containing the first region A (dark portion), (b) a mesh mainly containing the second region B (bright portion), and (c) the first region A and the second region. Each mesh in which the region B is mixed (portion where light and dark are mixed) is counted. (A) and (b) are included in the count of the first area A or the second area B as 1 square, and (c) are counted as 0.5 square in the count of the first area A and the second area B, respectively. Include. The ratio of the first area A and the second area B is obtained as the ratio of the number of meshes counted, and the area (cross section) of the first area A relative to the area (cross-sectional area) of the observation area of the mixed granular material 50 is determined from the ratio. (Area) ratio is calculated.

  In the mixed granule 50, the total blending amount of the inorganic filler 10 and the organic fiber 20 and the blending amount of the resin 30 are set in a weight ratio of 2: 1 to 30: 1, preferably 4: 1 to 20: Set to 1. When the weight ratio is smaller than 2: 1 (that is, when the total amount of the inorganic filler 10 and the organic fiber 20 is less than twice the amount of the resin 30), the amount of the resin 30 is excessive. Therefore, the inorganic filler 10 and the organic fiber 20 are buried in the resin 30, and the water retention and fertilizer retention of the artificial soil particle 100 finally obtained may be reduced. On the other hand, when the weight ratio is larger than 30: 1 (that is, when the total amount of the inorganic filler 10 and the organic fiber 20 exceeds 30 times the amount of the resin 30), the amount of the resin 30 is insufficient. For this reason, the bonding strength between the inorganic filler 10 and the organic fiber 20 is insufficient, and the artificial soil particle 100 finally obtained is easily collapsed.

  The artificial soil particles 100 have a particle size distribution of 0.5 to 12 mm, preferably 0.7 to 6 mm. When a large number of particles having a particle size smaller than 0.5 mm are included, when an artificial soil medium is configured using the artificial soil particles 100, gaps formed between the artificial soil particles 100 are reduced, and cultivated plants are used in the gaps. Possible moisture (easy-to-use water) is strongly adsorbed and air permeability is lowered. As a result, oxygen cannot be sufficiently supplied to the roots of cultivated plants, and root rot may occur. On the other hand, when many particles having a particle diameter larger than 12 mm are included, a gap formed between the artificial soil particles 100 becomes large, and a force for holding moisture in the gap is weakened, so that water retention is reduced. Therefore, it is necessary to increase the frequency of irrigation to the cultivated plant, and it takes time and effort to cultivate foliage plants, potted flower buds and the like.

  The artificial soil particles 100 can contain a colorant (not shown) in the mixed granule 50 in order to enhance the beauty and interior properties. In this case, the colorant can be dispersed in the first region A and / or the second region B to give the artificial soil particles 100 a color. As a colorant, a powder colorant or a liquid colorant can be used. When a powder colorant is used, it may be directly mixed with the raw material containing the inorganic filler, the organic fiber, and the non-emulsion binder as described in the “mixing step” described later. When using a liquid colorant, it may be added to the granulation liquid as described in the “granulation step” described later. As the colorant, pigment-based colorants, dye-based colorants, food additives, and the like can be used. When the mixed granule 50 contains a colorant, the artificial soil particle 100 can create a unique atmosphere that is not found in natural soil. Therefore, an appropriate colorant can be selected according to the scene in which the artificial soil particle 100 is used. For example, it can be suitably used as a growth medium for indoor ornamental plants and potted flower buds.

  By the way, when using the artificial soil particles 100 as a growth medium for foliage plants, potted flower buds, etc., it is not assumed that the medium is changed once the use is started (or the replacement frequency is low). Measures to maintain aesthetics and cleanliness. Since artificial soil particles 100 of the present invention are selected from materials and particle sizes suitable as non-emulsion binders, discoloration is unlikely to occur. The agent may discolor due to deterioration over time, or may fade due to the influence of ultraviolet rays, moisture, or the like. Therefore, when the artificial soil particles 100 are colored, a discoloration preventing layer (not shown) can be provided on the surface of the mixed granular material 50 as necessary. In this case, if a discoloration preventing agent is contained in the discoloration preventing layer, discoloration and fading of the colorant can be suppressed. The discoloration prevention layer does not need to be provided on the entire surface of the mixed granule 50, and a certain discoloration prevention effect can be obtained if it is provided on 50% or more of the surface area of the mixed granule 50. Moreover, it is also possible to contain the discoloration preventing agent in the raw material of the artificial soil particle 100 so that the discoloration preventing agent is dispersed throughout the artificial soil particle 100. In this case, the discoloration of the artificial soil particles is further suppressed, and an artificial soil having excellent interior properties can be obtained. Examples of the discoloration preventing agent include resins such as ethylene / glycidyl methacrylate copolymer.

<Method for producing artificial soil particles>
The artificial soil particles of the present invention can be produced by executing a mixing step, a granulating step, and a hardening step, and further performing a coating step and a particle size adjusting step as necessary. Through these series of steps, it is possible to produce artificial soil particles that have high durability and water resistance, are easy to handle, and have excellent aesthetics while maintaining basic performance as soil. Hereinafter, a method for producing artificial soil particles will be described.

[Mixing process]
FIG. 2 is a flowchart showing a procedure for producing the artificial soil particles of the present invention. The symbol “S” shown in the figure means a step. First, the inorganic filler, the organic fiber, and the non-emulsion binder that are raw materials of the artificial soil particles are mixed and stirred (S1: mixing step). The mixing step is performed by charging the inorganic filler, organic fiber, and non-emulsion binder into a stirrer (granulator) and stirring until the raw materials are sufficiently mixed. The order of putting the raw materials into the stirrer may be all at the same time or may be different. For example, the inorganic filler and the organic fiber may be first added and stirred, and the non-emulsion binder may be added after both of them are sufficiently familiar. When mixing non-emulsion binders, it is not necessary to add surfactants, etc., so the artificial soil particles finally obtained do not generate foaming even when wet due to irrigation etc., and are easy to use It will be a thing. As the non-emulsion binder, resin powder such as polyolefin, polyurethane, latex and the like can be used. Among these, resin powders made of polyolefins such as polyethylene resin (PE) and low density polyethylene resin (LDPE) are excellent in water resistance and durability, and are therefore suitable for use as artificial soil particles. As described above, the resin powder used as the non-emulsion binder has a 50% particle size range of 15 to 355 μm, preferably 75 to 180 μm, and a melt flow rate (temperature: 190 ° C.) measured according to JIS K7210. , Load: 2.16 kgf) is 50 g / 10 min or more, preferably 58 g / 10 min or more. Here, the x% -containing particle size range is a particle size range in which x% of the total number of particles is included with the median particle size as the median value in the particle size distribution of the resin powder in which the median particle size is indicated. means. For example, when the median particle size is 20 μm, the 50% particle size range can be 15 to 35 μm, and the 80% particle size range can be 10 to 40 μm. When the median particle size is 130 μm, the 50% containing particle size range can be 75 to 180 μm, and the 80% containing particle size range can be 40 to 250 μm. When the median particle size is 250 μm, the 50% content particle size range can be 180-355 μm, and the 80% content particle size range can be 50-500 μm. In order to set the 50% particle size range to 15 to 355 μm, three kinds of resin powders having a median particle size of 20 μm, 130 μm, and 250 μm may be mixed at an appropriate blending ratio. If the resin powder having such properties is used, discoloration or fading of artificial soil particles that may occur due to deterioration of the inorganic filler or organic fiber with time can be minimized. Moreover, if the resin powder having the appropriate melt flow rate described above is used, the binding force between the inorganic filler and the organic fiber can be effectively increased, while maintaining the basic performance of the artificial soil particles finally obtained. Water resistance and durability can be improved.

  The amount of each raw material is such that the total amount (a) of the inorganic filler and organic fiber and the amount (b) of the non-emulsion binder are 2: 1 to 30: 1 in a weight ratio (a: b). It is preferably adjusted to be 4: 1 to 20: 1. When the weight ratio (a: b) is smaller than 2: 1 (that is, when the total amount (a) of the inorganic filler and the organic fiber is less than twice the amount (b) of the non-emulsion binder. ) Since the blending amount of the non-emulsion binder becomes excessive, the inorganic filler and the organic fiber are buried in the non-emulsion binder, and the water retention and fertilizer retention of the artificial soil particles finally obtained may be reduced. There is. On the other hand, when the weight ratio (a: b) is greater than 30: 1 (that is, the total amount (a) of the inorganic filler and the organic fiber exceeds 30 times the amount (b) of the non-emulsion binder. ), The amount of the non-emulsion binder is insufficient, so that the binding force between the inorganic filler and the organic fiber becomes insufficient, and the artificial soil particles finally obtained are liable to collapse.

  In the case of coloring artificial soil particles, a coloring agent can be mixed with the raw material in the mixing step. In this case, since the inorganic filler, the organic fiber, and the non-emulsion binder mixed in the mixing step are all non-aqueous materials (non-wetting materials), it is possible to use a non-aqueous powder colorant as a colorant. preferable. In this case, the powder colorant is preferably a pigment composed of nano-order ultrafine particles. This is because the inorganic filler contained in the artificial soil particles usually has a micron order size, and if a general micron order pigment is used, it becomes a spotted pattern when the inorganic filler and the pigment are mixed. .

[Granulation process]
Next, a granulating liquid is added to the mixture of the inorganic filler, organic fiber, and non-emulsion binder obtained in the mixing step, and stirring with a stirrer (granulator) is continued as it is. Then, the mixture is gradually granulated while entraining the granulation liquid, and a mixed granule that is the original shape of the artificial soil particles is generated (S2: granulation step). Thus, the granulation liquid binds the raw materials contained in the mixture while adjusting the mixture to a particle shape. For this reason, a viscous liquid is used as the granulating liquid. As granulation liquid, agar, alginate, cellulose, starch, carrageenan, gum arabic, pectin, locust bean gum, xanthan gum, tara gum, guar gum, tamarind seed gum, psyllium seed gum, hyaluronic acid, chitin, chitosan, glue, etc. A natural polysaccharide dissolved or dispersed in water is preferably used. Moreover, it is also possible to use what melt | dissolved or disperse | distributed water-soluble polymers and hydrophilic polymers, such as polyvinyl alcohol, polyvinyl acetate, methylcellulose, carboxymethylcellulose, hydroxypropyl methylcellulose, and polyacrylate, to water. . The granulation step can be performed by a known granulation method such as rolling granulation, fluidized bed granulation, stirring granulation, compression granulation, extrusion granulation, crush granulation, melt granulation, spray granulation, or the like. .

  When coloring artificial soil particles, the powder colorant was mixed in the above mixing process, but instead of or in addition to mixing the powder colorant, a liquid colorant was added along with the granulation liquid used in the granulation process. can do. In this case, it is preferable to use a dispersion of ultrafine pigment as the liquid colorant. Since the liquid colorant can easily penetrate into the inside of the mixed granule and can be uniformly colored, the artificial soil particles finally obtained are colored in a vivid color, and the artificial soil has excellent interior properties. it can. In the granulation step, a discoloration inhibitor can be added together with the granulation liquid. In this case, since the discoloration inhibitor is dispersed throughout the artificial soil particles and discoloration due to deterioration over time is prevented, the added value of the artificial soil can be further increased. Examples of the discoloration preventing agent include resins such as ethylene / glycidyl methacrylate copolymer.

  When making an artificial soil particle carry | support a fertilizer component, a fertilizer component can be added to a granulation liquid. When the granulation process of a mixture is performed using the granulation liquid containing a fertilizer component, a fertilizer component adheres to an inorganic filler, organic fiber, and a non-emulsion binder, and is hold | maintained from the surface of a mixed granule to the inside. In the artificial soil particles composed of this mixed granular material, the fertilizer component is first eluted from the surface of the mixed granular material by irrigation, plant root acid, etc., and then the fertilizer component retained inside the mixed granular material gradually To elute. Such artificial soil particles having a sustained release property of fertilizer are suitable as a growth medium for foliage plants and potted flower buds that are cultivated over a long period of time. In addition, when the material which has ion exchange ability is used as an inorganic filler, since the fertilizer component is carry | supported not only by adhesion to a raw material but by an inorganic filler by ion exchange, the sustained release period of a fertilizer can further be extended. Incidentally, since the structure of the artificial soil particles is fixed by the hardening process described later, the structure as the artificial soil particles is maintained even after the fertilizer component is removed. Therefore, the structure of the artificial soil particles is not easily collapsed and no fine powder or the like is generated, so that the handling becomes easy.

[Curing process]
Next, the mixed granule containing the inorganic filler, organic fiber, and non-emulsion binder produced by the granulation step is cured (S3: curing step). The curing step can be performed in various ways depending on the properties of the non-emulsion binder. For example, when the non-emulsion binder contains a thermoplastic resin, the mixed granule is once heated to the melting point of the non-emulsion binder or higher, and the non-emulsion binder is fused to the inorganic filler and the organic fiber. Next, the mixed granule is cooled, and the non-emulsion binder is solidified to fix the inorganic filler and the organic fiber. Thereby, the mixture of the inorganic filler, the organic fiber, and the non-emulsion binder is cured while maintaining the particle shape. As other curing processes, for example, when the non-emulsion binder contains a crosslinkable resin that is crosslinked (cured) by heating or light irradiation, the inorganic filler, the organic fiber, and the non-emulsion bond are bonded by a thermosetting reaction or a photocrosslinking reaction. The mixture of agents can be cured into a particle shape.

  The cured granulated product obtained by the curing process is one in which inorganic fillers and organic fibers are bonded and fixed by a non-emulsion binder. Since the non-emulsion binder is a resin powder, the inorganic filler and the organic fiber are not completely covered by the non-emulsion binder, and the inorganic filler and the organic fiber are fixed in a state where they are appropriately exposed. . Therefore, this hardened granulated product balances the water retention and fertilization properties inherent to the inorganic filler and organic fiber with the water resistance and durability derived from the non-emulsion binder.

[Coating process]
The cured granulated product obtained by the above curing process can withstand even if used as artificial soil particles as it is, but the surface of the cured granulated product is exposed, so when used for a long time , May deteriorate due to moisture, ultraviolet rays, friction, etc. For example, when artificial soil particles are colored with a colorant, discoloration, discoloration, fading, etc. may occur. Therefore, after the above-described curing step, it is possible to perform coating on the surface of the cured granulated material as necessary. For example, the surface is coated with a discoloration inhibitor (S4: coating step). As the discoloration preventing agent in this case, for example, a resin such as an ethylene / glycidyl methacrylate copolymer can be used. The discoloration inhibitor is preferably in the form of fine particles having a particle diameter of 1 μm or less. The coating process can be carried out by spraying the above-mentioned discoloration preventing agent directly on the surface of the cured granulated product, or by immersing the cured granulated product in a dispersion containing the discoloration preventing agent and pulling it up. It is also effective to repeat the coating process a plurality of times. In this case, since the surface of the artificial soil particles is coated with a resin composed of a discoloration preventing agent, in addition to the discoloration preventing effect by the discoloration preventing agent, the effect of reinforcing the artificial soil particles by the coating is also obtained.

(Granularity adjustment process)
When an artificial soil medium is constructed using artificial soil particles, if the particle size distribution of the artificial soil particles is moderately aligned, not only the artificial soil particles but also the gaps formed between the artificial soil particles Moisture can be retained. Therefore, when configuring an artificial soil medium, the particle size distribution of the artificial soil particles is adjusted to 0.5 to 12 mm, preferably 0.7 to 6 mm (S5: particle size adjusting step). When the particle size of the artificial soil particles is smaller than 0.5 mm, the gaps formed between the artificial soil particles are reduced, and moisture (easy-to-use water) that can be used by the cultivated plants is strongly adsorbed in the gaps so that the air permeability is increased. descend. As a result, oxygen cannot be sufficiently supplied to the roots of cultivated plants, and root rot may occur. On the other hand, when the particle diameter of the artificial soil particles is larger than 12 mm, the gap formed between the artificial soil particles is increased, and the water retaining force is weakened to reduce the water retention capacity. Therefore, it is necessary to increase the frequency of irrigation to the cultivated plant, and human labor is required when cultivating foliage plants, potted flower buds and the like. The particle size adjustment step can be performed by sieving or the like, but in the above-described granulation step, when the mixed granule containing the inorganic filler, the organic fiber, and the non-emulsion binder is generated, the particle size distribution is approximately 0.00. If it can adjust to 5-12 mm, it is not necessary to perform a particle size adjustment process anew, and in this case, a granulation process will serve as a particle size adjustment process. Artificial soil particles whose particle size distribution is appropriately adjusted can be suitably used as a growth medium for foliage plants and potted flower buds.

  In accordance with the method for producing artificial soil particles described above, artificial soil particles (Examples 1 to 9) containing an inorganic filler, an organic fiber, and a resin derived from a non-emulsion binder were produced. Each artificial soil particle was observed with an optical microscope, and its structure (average size of the first region where the resin is present, ratio of the cross-sectional area of the first region to the total cross-sectional area of the mixed granular material) was specified. Further, each artificial soil particle was evaluated for its initial water absorption, water resistance in water, and anti-color change property.

<Production of artificial soil particles>
In accordance with the composition of raw materials shown in Table 1 (unit: parts by weight), artificial soil particle base materials (inorganic fillers, organic fibers, and binders) are added to a stirring and mixing granulator (MGS12 manufactured by G-Labo Co., Ltd.). Then, after stirring and rolling for several minutes, the granulation liquid was added and further stirred and rolled for about 10 minutes to form a granulated body. Diatomaceous earth (Radiolite (registered trademark) # 1500, manufactured by Showa Chemical Industry Co., Ltd.) is used as the inorganic filler, and cellulose fiber (KC Flock (registered trademark) W-100GK, manufactured by Nippon Paper Industries Co., Ltd.) is used as the organic fiber. ) And three types of polyethylene resin powders (A, B, C), which are non-emulsion binders, were used as binders. The polyethylene resin powder A has a median particle size of 250 μm, a 50% content particle size range of 180 to 355 μm, an 80% content particle size range of 50 to 500 μm, and a melt flow rate of 55 g / 10 minutes. The polyethylene resin powder B has a median particle size of 130 μm, a 50% containing particle size range of 75 to 180 μm, an 80% containing particle size range of 40 to 250 μm, and a melt flow rate of 58 g / 10 min. Polyethylene resin powder C has a median particle size of 20 μm, a 50% containing particle size range of 15 to 35 μm, an 80% containing particle size range of 10 to 40 μm, and a melt flow rate of 69 g / 10 min. For the granulating liquid, 6 parts by weight of potassium alginate (manufactured by Kimika Co., Ltd.) and 6 parts by weight of agar (MS-700, manufactured by Marine Science Co., Ltd.) were dissolved in 1200 parts by weight of tap water. . The granulated body is dried with hot air of 60 to 80 ° C., and further heat treated at 130 ° C. for 2 hours to melt the polyethylene resin powder to bond diatomaceous earth and cellulose fibers, and cool this to cool the Example 1 Nine artificial soil particles were obtained.

<Structure of artificial soil particles>
For the artificial soil particles of Examples 1 to 6, the average size of the first region where the polyethylene resin is present, and the ratio of the cross-sectional area of the first region to the total cross-sectional area of the artificial soil particles (mixed granule) are observed with a microscope. Obtained by image analysis. The results are shown in Table 2. However, for the artificial soil particles of Examples 7 to 9, since the particle size of the polyethylene resin powder C used as a raw material is small and image analysis is difficult, data is not shown. A microscopic image of each artificial soil particle is shown in FIG.

<Characteristic evaluation of artificial soil particles>
1. Initial water absorption Stainless steel cups (diameter 50 mm, depth 51 mm) are provided with a number of drain holes with a hole diameter of about 1 mm at a pitch of about 2 mm on the bottom surface, the water content is adjusted to 5% in the stainless cup, and particles are obtained by sieving. A sample filled with 100 cc of artificial soil particles (artificial soil medium) whose diameter was adjusted to 2 to 4 mm was used. First, the weight of the sample was measured, 50 cc of water was dropped on each sample, and after confirming that water was not discharged from the drain hole, the weight of the sample was measured again. And the amount of water absorption was calculated | required from the weight change of the sample before and behind water dripping, and this was made into initial stage water absorption.
2. Durability in water 100 cc of water and 3 g of artificial soil particles (artificial soil medium) were put into a transparent container, stirred for 24 hours at 300 rpm using a stirrer, and then the state of artificial soil particles in water was visually observed. . “◯” indicates that no change was observed, “Δ” indicates that a slight collapse was observed, and “x” indicates a complete collapse.
3. Anti-discoloration property A plant was cultivated in an artificial soil medium, and the change in the surface color of the artificial soil particles during cultivation was observed visually. “◯” indicates that no change was observed, “Δ” indicates that a slight discoloration was observed, and “×” indicates a discoloration as a whole.
Furthermore, the above results 1 to 3 were comprehensively evaluated. The more “+”, the better the balance of performance. Table 3 shows the results of the characteristic evaluation test.

  According to the characteristic evaluation test, it was confirmed that the artificial soil particles of Examples 1 to 9 have a certain performance or more with respect to initial water absorption, durability in water, and discoloration prevention. In particular, the artificial soil particles of Examples 4 to 6 were excellent in the balance of each performance, and were confirmed to be useful as artificial soil particles for growing media such as foliage plants and flower buds.

  The artificial soil particles of the present invention are suitably used as a growth medium for indoor houseplants and potted flower buds, but can also be used as a growth medium for vegetables grown in plant factories and the like.

10 Inorganic filler 20 Organic fiber 30 Resin 50 Mixed granule (cured granulated product)
100 Artificial soil particles A 1st area B 2nd area

Claims (10)

Artificial soil particles comprising a mixed granule containing inorganic filler, organic fiber, and resin,
The mixed granule has a first region mainly containing the resin, and a second region mainly containing the inorganic filler and the organic fiber,
In the cross-sectional view of the mixed granular material, the first region is composed of a plurality of island portions having an average size of 10 to 700 μm, and the cross-sectional area of the first region with respect to the total cross-sectional area of the mixed granular material is 5 to 60. % Artificial soil particles.   In the mixed granular material, the total amount (a) of the inorganic filler and the organic fiber and the amount (b) of the resin are 2: 1 to 30: 1 in a weight ratio (a: b). The artificial soil particle according to claim 1, which is set.   The resin is derived from a resin powder having a 50% particle size range of 15 to 355 μm and a melt flow rate (temperature: 190 ° C., load: 2.16 kgf) measured in accordance with JIS K7210 of 50 g / 10 min or more. The artificial soil particle according to claim 1 or 2.   The artificial soil particle according to claim 3, wherein the resin powder is a polyolefin resin powder.   The artificial soil particle according to any one of claims 1 to 4, wherein the inorganic filler is white diatomaceous earth, and the organic fiber is cellulose.   The artificial mixed particle according to any one of claims 1 to 5, wherein the mixed granule includes a colorant and / or a discoloration preventing agent.   The artificial soil particle according to any one of claims 1 to 6, wherein a surface of the mixed granular material is coated with a discoloration inhibitor.   The artificial soil culture medium using the artificial soil particle as described in any one of Claims 1-7.   The artificial soil medium according to claim 8, wherein a particle size distribution of the artificial soil particles is adjusted to 0.5 to 12 mm.   The artificial soil medium according to claim 8 or 9, which is a growth medium for florets or foliage plants.

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