JPH05268839A - Soil capable of reserving heat and structure for reserving heat of soil - Google Patents

Abstract

PURPOSE:To obtain soil capable of reserving the heat and simply keeping a temperature suitable for cultivating a plant at a low cost and further a structure for reserving the heat of soil. CONSTITUTION:The objective soil 2 comprises earth (2a) and a heat reserving material (2b) and is capable of reserving the heat. The heat reserving material (2b) is prepared by mixing 100 pts.wt. paraffins which are a heat reserving component with 5-30 pts.wt. hydrocarbon-based organic polymer which is a binder component by a mechanical means. Furthermore, the objective structure (T) for reserving the heat of the soil 2 having an auxiliary heating means 5 additionally installed in the soil 2 capable of reserving the heat is obtained. Thereby, the soil temperature can be kept within a range suitable for cultivating a plant and the running cost for reserving the heat of the soil can remarkably be reduced. The surface treatment of the heat reserving material, the formation of a shielding layer in the structural material and a vessel or a tank for housing the heat reserving material are not required. As a result, the cost for forming the structure for reserving the heat of the soil can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil capable of storing heat and a heat storage structure of the soil which can be used for plant cultivation, horticulture, a greenhouse, etc. and can maintain a temperature suitable for plant growth.

[0002]

2. Description of the Related Art In plant cultivation, it is common practice to form a constant temperature environment in a greenhouse or a greenhouse to promote plant growth. To be more specific, circulate heated air in the aboveground space in the house, lay a pipe in the soil underground to circulate hot water, or install a heating means such as an electric heater to keep the ground and soil warm. Has been done. By this heat retention, the freezing of the soil can be prevented, and the plants are protected from the adverse effects on the plant cultivation due to the freezing of the soil.

[0003]

However, even if the object to be kept warm is a small volume of soil such as a potted plant, it is troublesome to install an electric heater, and it is necessary to keep the soil warm in a vast greenhouse or greenhouse. Providing the heating means is costly and time-consuming.

Therefore, it is conceivable to apply a heat storage material, which has been attracting attention as a functional material in recent years, as a heat insulating material for soil. As a heat storage material, it is known that a latent heat storage material that utilizes phase change latent heat can be efficiently used. Above all, as a low temperature type latent heat storage material that changes phase near room temperature,
There are inorganic heat storage materials such as water, calcium chloride hydrate, sodium sulfate hydrate, sodium acetate hydrate, etc., and organic heat storage materials such as paraffins. Each one is used.

By the way, since the heat storage material undergoes a phase change,
There is a fatal drawback that when it stores heat, it becomes liquid rather than solid. For this reason, a method of preventing liquefaction by impregnating cross-linked polyethylene or the like with paraffins has been proposed, but the disadvantage that paraffins gradually fluidize and the surface becomes sticky in a relatively short time and liquefies during heat storage cannot be solved. ..

Therefore, in order to put the heat storage material into practical use as a heat insulating material for soil, a treatment for preventing the outflow of heat storage components, for example, a surface treatment or a shield layer is formed.
Since it is necessary to separately provide a container or a tank for accommodating this, the cost becomes high, and the installation work is troublesome, and it has not been put to practical use yet.

An object of the present invention is to solve the above problems and to provide a soil capable of storing heat, which can easily and inexpensively keep the soil at a temperature suitable for plant cultivation. Another object of the present invention is to provide a soil heat storage structure using the soil capable of storing heat.

[0008]

As a result of various studies to solve the above problems, the present inventors have found that a heat storage material obtained by mixing a composition comprising a specific heat storage component and a binder component by mechanical means. It was found that the heat storage material does not fluidize during heat storage, and the above object was achieved by mixing this heat storage material with soil or forming a heat storage material portion in soil.

That is, the heat-storable soil of the present invention is heat-storable soil containing soil and a specific heat storage material, wherein the heat storage material is 100 parts by weight of paraffins as a heat storage component and carbonization of a binder component. The hydrogen-based organic polymer is mixed with 5 to 30 parts by weight by a mechanical means.

Further, the soil heat storage structure of the present invention comprises an auxiliary heating means provided side by side with the soil capable of storing heat.

[0011]

According to the constitution of the present invention, the soil capable of storing heat can be obtained by a simple method of mixing the heat storage material with the soil or forming the heat storage material portion in the soil. Further, the heat storage material stores heat such as solar heat, heat in the house, and auxiliary heating, and radiates the heat at night or in the cold, so that the soil temperature can be maintained within a range suitable for plant cultivation. Moreover, since the specific organic heat storage material that does not flow during heat storage is dispersed, heat storage components do not flow out and the surrounding soil is not contaminated. Moreover, since a specific organic heat storage material having a large heat storage amount is used, heat is efficiently absorbed and radiated, and heat radiation is continued for a long time to keep the soil warm. Furthermore, since the auxiliary heating means is also provided, the soil temperature can be accurately maintained within a range suitable for plant cultivation.

Next, the present invention will be described in more detail. The soil capable of storing heat of the present invention is obtained by blending various soils for plant cultivation with a heat storage material obtained by mechanically mixing the following specific composition.

The heat storage material may be prepared by mixing paraffins as a heat storage component and a binder component made of a hydrocarbon organic polymer in an amount of 5 to 30 parts by weight per 100 parts by weight of the paraffins by mechanical means. What is used is used.

As the above-mentioned paraffins, JIS K
An organic compound having a T _max of 0 to 50 ° C., preferably 0 to 35 ° C., measured according to 7121 (Plastic transition temperature measuring method) is used. If this T _max is too low, the temperature of the soil will be low, and the heat retaining function will not be exerted, and if it is too high, natural thermal energy will not be sufficiently accumulated.

Specific preferred examples of the paraffins include various paraffins, waxes and waxes of an aliphatic saturated hydrocarbon having a linear or side chain represented by C _n H _{2n + 2} , and α-olefins. Examples thereof include higher alcohols, fatty acids, esters of these fatty acids with monohydric or dihydric higher alcohols, polyethylene glycol, and the like, and these are used as one kind or a mixture of two or more kinds.

In the above hydrocarbon-based organic polymer, the main chain is basically hydrocarbon, and the content of other components (eg, O, N, Si, halogen, etc.) in the main chain is 10% by weight or less. , And preferably 1 or 2 or more kinds of the hydrocarbon-based organic polymer of 5% by weight or less are used. Examples of such hydrocarbon organic polymers are shown below.

(1) Polyolefin polymers: homopolymers of α-olefins such as polymethylene, polyethylene and polypropylene, copolymers of olefins,
Examples thereof include copolymers of α-olefins with other monomers such as vinyl acetate, ethyl acrylate, ethyl methacrylate, and the like, and lightly halogenated polymers thereof. It may be amorphous to low crystalline,
It may be crystalline.

(2) Thermoplastic elastomers: Among the known or known thermoplastic elastomers in the fields of rubber and plastics, the paraffins used have a temperature range of T _max + 10 ° C. Preferably, those having rubber elasticity in the temperature range of T _max + 20 ° C. are used. Of course, it is also possible to use one that maintains rubber elasticity at a temperature higher than T _max + 20 ° C. Specifically, various conventionally known thermoplastic elastomers such as styrene type, olefin type, urethane type and ester type can be exemplified.

(3) Hydrocarbon rubbers: natural rubber, styrene-butadiene-copolymer rubber, butyl rubber, isoprene rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene terpolymer rubber, ethylene −
Examples thereof include vinyl acetate copolymer rubber and ethylene-ethyl acrylate copolymer rubber. The hydrocarbon-based organic polymer may be either crosslinkable or non-crosslinkable.

The amount of the hydrocarbon organic polymer used is 5 to 30 parts by weight based on 100 parts by weight of paraffins. If it is less than 5 parts by weight, the paraffins tend to exude at T _max or more, while if it exceeds 30 parts by weight, the heat storage amount decreases in proportion to the use amount of the paraffins decreasing. ..

Crosslinking and vulcanization of the above-mentioned hydrocarbon organic polymer are carried out during or after mixing with paraffins, if necessary. As the method of crosslinking or vulcanizing, generally used chemical crosslinking, silane crosslinking (water crosslinking), electron beam or radiation irradiation, or the like can be adopted.

When the heat storage material is cross-linked, the degree of cross-linking is determined according to JIS regardless of which cross-linking method is adopted.
According to C3005, the crosslinked product in the composition has a gel fraction of 1% by weight or more, preferably 2% by weight or more. By setting the degree of cross-linking to 1% or more, preferably 2% or more, even if the heat storage material is heated to T _max or more of the used paraffins, the heat storage material retains its original shape without melting or dropping. It becomes possible to do.

The heat storage material used in the present invention is obtained by mixing the above-mentioned paraffins and a hydrocarbon-based organic polymer by mechanical means at the above-mentioned proportions. The mixing here means paraffins. A state in which any of the components to be mixed can be flow-deformed by an external force by swelling, preferably dissolving the remaining components in the melt of at least one component of the hydrocarbon organic polymer and by the high temperature. Means to be stirred, mixed, or kneaded.

For example, a mode in which a hydrocarbon-based organic polymer is dissolved in a melt of paraffins maintained at 100 to 200 ° C. and the resulting high temperature solution is stirred and mixed, and a temperature at which each mixed component is softened, for example, 50 Examples include a mode in which kneading and mixing are performed at a temperature of up to 250 ° C. using an ordinary kneading machine such as a two-roll mill, a Banbury mixer, an extruder, and a twin-screw kneading extruder. Mixing is preferably as complete as possible, but generally 1
It is sufficient to perform mixing for about 150 minutes and visually judge that they are uniformly mixed.

The composition which has been made into a solution by the above-mentioned mixing can be used as it is or by cooling it slightly to form a heat storage material having an arbitrary shape. The shape of the heat storage material is powder, granular,
It can be formed into pellets, chips, fibers, rods, horns, sheets, plates, blocks and the like. For example, the composition in the form of a solution can be extruded into a sheet shape or a plate shape by an extruder, and can also be formed into a rod shape or a pipe shape by the extruder. Further, the plate-shaped or block-shaped molded product can be crushed into chips, or the rod-shaped or pipe-shaped molded product can be shredded into granules or pellets.

If desired, various additives may be added to the heat storage material used in the present invention. For example, antioxidants, antioxidants, colorants, pigments, antistatic agents, etc. are blended, and depending on other uses, antifungal agents, flame retardants, etc., and metal powders, metal fibers, metals to improve heat transfer properties. Oxides, carbon, carbon fibers and the like can be used in combination.

The heat storage material thus obtained is sprayed directly on the soil, directly mixed with the soil and dispersed in the soil, or a mixture previously mixed with the soil is dispersed on the soil or dispersed in the soil. Alternatively, the heat storage material portion is formed in the soil to form the heat storage soil. At this time, even if an additive such as fertilizer is added to the soil, there is no effect and there is no problem. Further, by selecting the size and shape of the heat storage material, a space can be formed in the soil capable of storing heat, and air in the soil can be circulated and held. Further, since the heat storage material itself has a heat insulating property, the heat storage material can be laid or a heat storage material portion can be formed to form a heat insulating layer in the soil.

When the heat storage material is directly mixed with soil, the amount of the heat storage material mixed is 10 to 70% by volume, preferably about 20 to 60% by volume. The mixing method is performed by simply mixing a small-sized heat storage material such as granules, chips, or pellets with the soil. The mixing amount of the heat storage material is 10
When it is less than the volume%, the heat storage amount is small and it is not effective for keeping the temperature of the soil, and when it exceeds 70 volume%, the content of the soil itself is small, which is not preferable for the growth of plants.

In the present invention, the heat storage material freely colored with the colorant or pigment can be dispersed to form colorful soil capable of storing heat. In addition, the specific gravity can be adjusted by adding an additive to the heat storage material to adjust the specific gravity, or by selecting the soil quality of the soil to be dispersed, so that heavy soil or light soil can be prepared depending on the application.

In the above, the heat retention of soil in greenhouses and greenhouses has been described, but it is also effective for heat preservation of potted soil of plants and soil laid under water in hydroponics, and also for heat preservation of medium such as porous polyurethane. Similarly, the heat storage material can be applied to retain heat.

In the present invention, the heat storage material can be a heat storage material having a desired heat storage temperature by selecting a heat storage component. Therefore, a heat storage material having an appropriate heat storage temperature may be selected and used according to the purpose of use. For example, a heat storage material having a heat storage temperature of 15 ° C. to 25 ° C. is suitable for cultivating tropical plants, orchids, etc. When this heat storage material is used, the growth of these plants can be promoted. Further, the heat storage material having a heat storage temperature of 0 ° C. to 14 ° C. stores heat at room temperature in the daytime and radiates heat when it becomes 0 ° C. or less at night, so that the soil does not freeze.

Further, in the present invention, an auxiliary heating means such as a hot water pipe or an electric heater can be provided in the heat storage soil to form a heat storage structure of the soil. FIG. 4 shows an example in which the auxiliary heating means is provided side by side.
The auxiliary heating means 5 is installed therein to form a soil heat storage structure T.

Specifically, when the vast soil 10 is to be kept warm, as shown in FIG. 4 (a), the upper part of the soil 10 is set as the heat storage soil 2 in which the heat storage material 2b is mixed with the soil 10, and this heat storage soil is used. Auxiliary heating means 5 such as an electric heater or hot water pipe in 2
To store natural energy in the daytime and to store heat energy at night with cheap electricity such as electricity at night and heat storage adjustment contract electricity. The heat is stored in the heat storage material. Further, as shown in FIG. 4B, the heat storage soil 2 is formed, and the heat storage material 2b layer is formed on the upper portion of the auxiliary heating means 5,
The soil 2a layer may be formed thereon.

In the above structure, when the auxiliary heating means 5 is operated to heat the heat storage soil 2, heat energy is stored in the heat storage material 2b. Then, when the heating is stopped, the temperature of the soil starts to decrease, but when the temperature becomes equal to or lower than the heat storage temperature of the heat storage material 2b, heat radiation starts from this heat storage material 2b, the temperature decrease of the soil 2 is suppressed, and It can maintain a constant temperature.

At this time, when the heat insulating layer 6 is formed on the boundary surface between the soil 10 and the heat storage soil 2 and the auxiliary heating means 5 is installed thereon, the thermal energy from the auxiliary heating means 5 is effectively stored. It is preferable because the heat is stored in 2b. In addition, in the case of keeping a small amount of soil such as potted plants and home gardening warm, a simple auxiliary heating means such as an electric heater is provided in the soil.

According to the above construction, the natural heat of the daytime is stored, and the heat energy supplied from the auxiliary heating means is stored in the heat storage material so as to be radiated in the cold at night and the like, so that the soil can be kept warm. Therefore, it is preferable.

[0037]

EXAMPLES Hereinafter, the present invention will be described more specifically by showing examples. Needless to say, the present invention is not limited to these examples. Example 1 [Preparation of heat storage material] Composition of heat storage material 100 parts by weight of C ₁₆ normal paraffin 20 parts by weight of SEBS thermoplastic elastomer for hydrocarbon polymer binder (trade name, manufactured by Clayton G Shell Chemical Co., Inc.) Antioxidant 0. 2 parts by weight of the above composition at a temperature of 130 ° C. with a stir mixer
Melt forced agitation for ~ 2 hours. The obtained mixture was poured into a mold and cooled to form a prismatic shaped product, which was further shredded to prepare a heat storage material of about 6 mm square. The heat storage temperature of this heat storage material was 16 ° C, and the heat storage amount was 40 cal / g. However,
The measurement is based on JIS K 7121 and JIS K 71.
22.

[Preparation of Soil that Can Store Heat] The heat storage material and the flower bed soil were mixed at a volume ratio of 1: 2 to prepare a heat storage soil. Then, as shown in FIG. 1, about 2 liters of heat storage soil 2 was placed in a beaker 1, a thermocouple 3 was attached to the center, and the temperature in the soil was adjusted by placing it in an atmosphere of room temperature (about 23 ° C.) to 5 ° C. When the temperature was measured and the temperature was measured again while returning to room temperature to examine the heat storage state and the heat radiation state, the results shown in FIGS. 2 and 3 were obtained.

Comparative Example 1 When the flower bed soil alone was used instead of the soil capable of storing heat in Example 1, the temperature was measured in the same manner as in Example 1 above, and the results shown in FIGS. 2 and 3 were obtained. As is clear from these figures, the temperature of the soil of Comparative Example 1 drops sharply and the temperature rises sharply. On the other hand, in the soil of Example 1, it takes a long time for the temperature to drop and the temperature to rise due to the heat radiation and heat absorption of the heat storage material. As described above, the soil capable of storing heat was excellent in heat retention.

Further, in the soil capable of storing heat, the heat storage component was not exuded at all even when the temperature was raised and lowered, and the heat storage component did not separate or flow out even if water was applied. ..

Example 2 and Comparative Example 2 2 liters of each of the soil capable of storing heat of Example 1 and the soil of Comparative Example 1 were placed in a beaker in the same manner as in Example 1,
The temperature in the soil was measured by leaving it outdoors for 24 hours. The change in outside air temperature was 7 to 18 ° C. As a result, Comparative Example 1
The temperature change in the soil was 7 to 17 ° C, whereas the temperature change in the soil in Example 1 was 12 to 16 ° C, and the range of the temperature change was extremely small.

Example 3 [Preparation of heat storage material] Composition of heat storage material C ₁₆ normal paraffin 25 parts by weight C ₁₈ normal paraffin 75 parts by weight SEBS thermoplastic elastomer for hydrocarbon polymer binder 13 parts by weight (trade name: Kraton) G Shell Chemical Co., Ltd.) Polyethylene wax 7 parts by weight Antioxidant 0.2 parts by weight A heat storage material was prepared from the above composition in the same manner as in Example 1. The heat storage temperature of this heat storage material is 21 ° C, and the heat storage amount is 30 cal /
It was g.

[Preparation of soil capable of storing heat]
It mixed with soil like Example 1 and produced the heat storage soil. A heat insulating agent was laid in a vinyl house, and the heat storage soil was laid on the upper surface of the heat storage agent to a thickness of about 25 cm to obtain heat storage soil. When the temperature inside and outside the vinyl house was measured for 24 hours, the outside air temperature was 7 to 18 ° C, while the inside temperature was 16 to 21 ° C, and the temperature difference was small, and
It was suitable for plant cultivation.

Comparative Example 3 A soil was prepared in a house in exactly the same manner as in Example 3 except that the flower bed soil was used in place of the heat storage soil. When the temperature inside and outside the vinyl house was measured for 24 hours, the temperature inside the house was 10 to 25 ° C., which was higher than the outside air, but the temperature difference was large and the temperature was considerably low at night.

Example 4 [Preparation of heat storage material] Composition of heat storage material C ₁₈ .alpha.-olefin (trade name Dialene 18 manufactured by Mitsubishi Kasei) 100 parts by weight SEBS thermoplastic elastomer for hydrocarbon polymer binder 13 parts by weight (product) Clayton G Shell Chemical Co., Ltd.) Polyethylene wax 7 parts by weight Talc 5 parts by weight Antioxidant 0.2 parts by weight The above composition was subjected to the same method as in Example 1 and the obtained mixture was poured into a mold and cooled. This was made into a rod-shaped molded product, which was further shredded to prepare a chip-shaped heat storage material that passed through a 16 mm mesh screen. The heat storage temperature of this heat storage material was 16 ° C, and the heat storage amount was 30 cal / g.

[Preparation of Heat Storage Structure] As shown in FIG. 4B, a heat insulating material 6 is laid in the soil 10 in a simple vinyl house (not shown), and an electric heater 5 is installed on the upper surface thereof.
The chip-shaped heat storage material 2b was laid thereon to a thickness of about 30 cm, and finally the flower bed soil 2a was laid to a thickness of about 25 cm to form a heat storage structure T for the soil 2. The heat storage material 2b of the heat storage structure T is operated by heating the heater 5 at midnight power while controlling the natural heat in the daytime and controlling the temperature of the soil 2 to a maximum of 20 ° C. at night to generate heat energy. Stored heat.
As a result, the outside air temperature was 0 to 14 ° C, but the temperature of the soil 2 was kept at 14 to 20 ° C throughout the day and night, which was suitable for plant cultivation.

Example 5 [Preparation of heat storage material] Composition of heat storage material 100 parts by weight of C ₁₄ normal paraffin 15 parts by weight of SEBS thermoplastic elastomer for hydrocarbon polymer binder (trade name: Kraton G Shell Chemical Co., Ltd.) polyethylene wax 10 parts by weight Antioxidant 0.2 parts by weight The above composition was treated in the same manner as in Example 4 to prepare a chip-shaped heat storage material. The heat storage temperature of this heat storage material was 2 ° C, and the heat storage amount was 40 cal / g.

[Preparation of soil capable of storing heat]
It mixed with soil like Example 1 and produced the heat storage soil. When this heat storage soil was applied to a flowerpot and left outdoors in winter, the heat storage soil did not freeze even though the temperature cooled to -5 ° C at night.

Comparative Example 4 In Example 5, the flower pots alone were applied to the flower pots, and the soil was frozen, and frost columns were observed.

[0050]

As described above, in the present invention, the heat storage material stores natural heat energy such as solar heat and heat in the house,
It radiates heat at night, so you can effectively use heat energy,
The soil temperature can be maintained within a range suitable for plant cultivation.

Further, since a heating device such as a normal hot water pipe or an electric heater is provided side by side to store heat by economical night power, the running cost for keeping the soil warm can be greatly reduced.

Further, since a specific organic heat storage material that does not flow the heat storage component during heat storage is used, it does not flow out into the soil, so surface treatment of the heat storage material, formation of a shielding layer in the structural material, and further heat storage Eliminates the need for containers and tanks to store materials,
The heat storage structure formation cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a diagram showing a heat storage state of soil capable of storing heat according to the present invention.

FIG. 3 is a diagram showing a heat radiation state of soil capable of storing heat according to the present invention.

FIG. 4 is a sectional view showing a heat storage structure of soil according to an embodiment of the present invention.

[Explanation of symbols]

 2: Soil capable of storing heat 2a: Soil 2b: Heat storage material 5: Auxiliary heating means T: Heat storage structure of soil

Claims (5)

[Claims] 1. A soil capable of storing heat, which contains soil and a heat storage material, wherein the heat storage material is a paraffin 100 as a heat storage component.
5 to 30 parts by weight of hydrocarbon-based organic polymer as a binder component
A soil capable of storing heat, characterized by being mixed with parts by weight by mechanical means. 2. The soil capable of storing heat according to claim 1, wherein the soil contains 10 to 70% by volume of a heat storage material. 3. The soil capable of storing heat according to claim 1, wherein the soil is soil in which a heat storage material is dispersed. 4. The soil capable of storing heat according to claim 1 or 2, wherein the soil has a heat storage material portion formed in the soil. 5. A heat storage structure of soil in which auxiliary heating means is provided side by side with soil capable of storing heat.