Environment-friendly soil conditioner and preparation method thereof

Abstract

The invention relates to an environment-friendly soil conditioner and a preparation method thereof, and particularly relates to a soil conditioner which can increase the moisture retention capacity of soil, realize soil granulation, pH adjustment, nutrient supply, microorganism mixing and the like, thereby not only creating optimal vegetation growth conditions, but also increasing the biochar content through biodegradation and improving the soil quality. Therefore, the environment-friendly soil conditioner and the manufacturing method thereof are provided.

Description

Technical Field

[0001] This invention relates to a soil conditioner and its manufacturing method, and more particularly to an environmentally friendly soil conditioner and its manufacturing method that can improve soil moisture retention by being mixed into natural or artificial soils and can also increase bio-carbon content through biodegradation, thereby mitigating global warming. Background Technology

[0002] Soil conditioners are substances used to improve the physical, chemical, and / or biological properties of soils that are obstructed by natural or human influences and affect plant growth, crop quality, and safety.

[0003] Obstacle soils include sandy soils, clay soils, structural obstacle soils, acid soils, saline soils, alkaline soils, and contaminated soils. As mentioned above, obstacle soils typically lead to problems such as sparse vegetation, fragile structure, hindered plant root growth, reduced reproductive capacity, or nutrient deficiency (nutrient imbalance, acidification, salinization, excessive or insufficient soil moisture, and toxic substances, etc.).

[0004] In particular, sandy soils, a type of obstacle soil, are mainly found in arid regions, especially in desertified soils. In arid areas, soil is easily eroded by wind or concentrated rainfall, reducing the survival rate of afforested trees. Moreover, due to the characteristics of sandy soils, water is difficult to retain, so when water is lost, nutrients in the soil are also lost, causing problems for the roots of trees or grasses to absorb water and nutrients, making it difficult to form forests or grasslands.

[0005] In arid regions as described above, techniques have been proposed to improve soil moisture by adding hygroscopic polymers such as sodium polyacrylate (ASAP) or polyacrylamide (Patent Documents 0001 and 0002) as a method to combat desertification and maintain soil moisture. However, organic matter containing fertilizers is unlikely to maintain or increase soil moisture, especially since polyacrylamide is classified as a Class II carcinogen and poses health hazards, and petroleum-based propylene is a major source of greenhouse gases. Therefore, its use should not continue to be considered to prevent environmental pollution.

[0006] Furthermore, while inorganic salts such as magnesium chloride (MgCl2) can help retain soil moisture, they are particularly prone to dissolving into water and being lost from the soil, especially in sandy soils, and eventually flowing into rivers and other aquatic ecosystems, negatively impacting the salinity of these water bodies. In addition, excessive use of inorganic salts can also lead to environmental problems such as soil acidification and plant dieback.

[0007] Furthermore, hygroscopic polymers take a long time to decompose in soil, and the hygroscopic polymers and / or their decomposition products in the soil can act as toxic components in the soil ecosystem, which may lead to environmental pollution problems.

[0008] Therefore, there is a need to develop a soil conditioner that can improve obstacle soils in arid regions without using inorganic salts or high molecules that cause soil toxicity as the main components, and can maintain / increase soil moisture, prevent the loss of soil fertilizer components, and enhance fertilizer effectiveness in afforestation or grassland formation and in agricultural activities in arid regions, in order to improve crop survival / yield.

[0009] Existing technical documents

[0010] Patent documents

[0011] (Patent Document 1) Korean Patent Registration No. 10-1264829 (Publication Date: January 23, 2013)

[0012] (Patent Document 2) Korean Patent Registration No. 10-2479792 (Publication Date: April 20, 2022) Summary of the Invention

[0013] Technical issues

[0014] The main objective of this invention is to solve the problems described above by providing an environmentally friendly soil conditioner and its manufacturing method that can improve soil moisture retention and increase biochar content through biodegradation, thereby mitigating global warming.

[0015] Problem-solving methods

[0016] To achieve the objectives described above, one embodiment of the present invention provides an environmentally friendly soil conditioner, characterized in that it comprises a thermoplastic resin containing 65% to 80% by weight of hydroxyethyl cellulose and 20% to 35% by weight of glycerol.

[0017] In a preferred embodiment of the present invention, the environmentally friendly soil conditioner further comprises 5 to 60 parts by weight of porous inorganic material relative to 100 parts by weight of thermoplastic resin, or further comprises 5 to 40 parts by weight of crosslinking agent relative to 100 parts by weight of thermoplastic resin.

[0018] In a preferred embodiment of the present invention, the porous inorganic material is selected from one or more of the group consisting of perlite, vermiculite, bentonite and zeolite.

[0019] In a preferred embodiment of the present invention, the crosslinking agent is one or more selected from the group consisting of citric acid, polyethylene glycol, and hexanediol.

[0020] A preferred embodiment of the present invention is characterized in that the viscosity of an aqueous solution in which the hydroxyethyl cellulose is dissolved at 2% by weight in water is measured at 20°C using a Brookfield viscometer and is between 10 cps and 250,000 cps.

[0021] Another embodiment of the present invention provides a method for manufacturing an environmentally friendly soil conditioner, characterized in that it includes: step (a) obtaining a mixture by mixing 65% to 80% by weight of hydroxyethyl cellulose with 20% to 35% by weight of glycerol; step (b) obtaining a thermoplastic resin by kneading and plasticizing the obtained mixture; and step (c) granulating the obtained thermoplastic resin.

[0022] In another preferred embodiment of the present invention, the method for manufacturing the environmentally friendly soil conditioner is characterized in that: in step (a) or step (c), a porous inorganic material and / or a crosslinking agent are further added and mixed, wherein the content of the porous inorganic material is 5 to 60 parts by weight relative to 100 parts by weight of the mixture in step (a) or to 100 parts by weight of the thermoplastic resin in step (c), and the content of the crosslinking agent is 5 to 40 parts by weight relative to 100 parts by weight of the mixture in step (a) or to 100 parts by weight of the thermoplastic resin in step (c).

[0023] In another preferred embodiment of the present invention, the porous inorganic material is selected from one or more of the group consisting of perlite, vermiculite, bentonite and zeolite.

[0024] In another preferred embodiment of the present invention, the crosslinking agent is one or more selected from the group consisting of citric acid, polyethylene glycol and hexanediol.

[0025] Another preferred embodiment of the present invention is characterized in that: the viscosity of the aqueous solution in which the hydroxyethyl cellulose is dissolved in water at 2% by weight is measured at 20°C using a Brookfield viscometer is 10 cps to 250,000 cps.

[0026] In another preferred embodiment of the present invention, the mixing in step (b) is performed at 50°C to 90°C at a speed of 300 rpm or higher.

[0027] In another preferred embodiment of the present invention, the granulation in step (c) is performed by pressing and molding into granules or pellets.

[0028] Invention Effects

[0029] According to the present invention, the environmentally friendly soil conditioner can improve the drought and dry growing environment of crops by enhancing soil moisture retention, and can also increase biochar content through biodegradable raw materials, thereby mitigating global warming.

[0030] Furthermore, the environmentally friendly soil conditioner according to the present invention has excellent molding and processing properties and is easy to adjust particle size, thereby enabling large-scale spraying or mechanical spraying. Therefore, the application of the soil conditioner can be conveniently carried out, thereby effectively shortening the operation time and saving spraying costs. Moreover, due to its excellent water absorption and durability, it can maintain stable performance for a long time. Attached Figure Description

[0031] Figure 1 (a) and (b) are photographs taken with a digital camera of the soil conditioners produced by Experimental Examples 1-3 and 1-4 of the present invention.

[0032] Figure 2 These are photographs taken with a digital camera of the soil conditioner produced through Experimental Examples 2-3 of the present invention. Detailed Implementation

[0033] The advantages and features of the present invention, and the methods for achieving them, will become even clearer through the following experimental examples, which will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the experimental examples disclosed below, but can be implemented in many different forms. The following experimental examples are merely to more completely disclose the present invention and to more fully explain the scope of the invention to those skilled in the art. The present invention should only be defined within the scope of the claims.

[0034] In describing this invention, detailed descriptions of relevant prior art will be omitted if it is determined that such detailed descriptions may obscure the essence of the invention.

[0035] When using terms such as "comprising," "having," and "constituting" as used in this specification, other parts may be added unless "only" is used. Unless otherwise expressly stated, elements expressed in the singular also include those expressed in the plural.

[0036] The various features of the multiple embodiments of the present invention can be partially or completely combined or integrated with each other, and can technically achieve multiple linkages and drives. The various embodiments can be implemented independently of each other, or they can be implemented together through association.

[0037] One aspect of the present invention relates to an environmentally friendly soil conditioner, characterized in that it comprises a thermoplastic resin containing 65% to 80% by weight of hydroxyethyl cellulose and 20% to 35% by weight of glycerol.

[0038] Generally speaking, cellulosic microorganisms can biodegrade while possessing properties such as moisture retention, salt tolerance, and pH stability. Therefore, they have recently been developed into various soil conditioners. However, because they are composed of strong hydrogen bonds, they undergo thermal decomposition below their melting point, making it difficult to mix with inorganic materials, crosslinking agents, or additives. In addition, they have a high molecular structure that is difficult to shape and process, thus failing to fully realize the role of soil conditioners.

[0039] Therefore, this invention uses a thermoplastic resin obtained by adding a specific amount of glycerol to hydroxyethyl cellulose with a specific viscosity to a cellulose derivative, and further mixing it with porous inorganic materials and / or crosslinking agents and granulating it. This provides a soil conditioner that improves mechanical properties while ensuring excellent molding and processing properties, thereby stably enhancing soil moisture retention. It also enables soil granulation, pH adjustment, nutrient supply, and microbial incorporation. Furthermore, it can increase biochar content through biodegradation. As a result, it is convenient to adjust the particle size of the product, which is conducive to large-scale spraying using machinery such as drones and tractors. Moreover, it is an environmentally friendly soil conditioner that can be biodegraded because it uses plant-based and natural raw materials.

[0040] The descriptions relating to each of the aforementioned components will be provided in the subsequent description of the manufacturing method of the environmentally friendly soil conditioner to avoid repetition.

[0041] Another aspect of the present invention relates to a method for manufacturing an environmentally friendly soil conditioner, characterized by comprising: step (a) obtaining a mixture by mixing 65% to 80% by weight of hydroxyethyl cellulose with 20% to 35% by weight of glycerol; step (b) obtaining a thermoplastic resin by kneading and plasticizing the obtained mixture; and step (c) granulating the obtained thermoplastic resin.

[0042] According to the method for manufacturing an environmentally friendly soil conditioner of the present invention, a mixture is first obtained by adding glycerol to hydroxyethyl cellulose [step (a)].

[0043] Hydroxyethyl cellulose (HEC) is a water-soluble polymer that appears as a white or light yellowish-white powder. Among cellulose derivatives, it has the best salt resistance and pH stability, as well as colloidal properties, moisturizing properties, and temperature resistance, thus it is recognized as a raw material that can be used in various fields for a variety of products.

[0044] In this invention, the hydroxyethyl cellulose used as the matrix resin can be hydroxyethyl cellulose with a viscosity of 10 cps or more, preferably 10 cps to 250,000 cps, and more preferably 100 cps to 250,000 cps. In this case, the viscosity of the hydroxyethyl cellulose is the viscosity measured at 20°C using a Brookfield viscometer when an aqueous solution of hydroxyethyl cellulose dissolved in water (hydroxyethyl cellulose: 2% by weight) is obtained.

[0045] If the viscosity of the hydroxyethyl cellulose is less than 10 cps, adhesion may occur after extrusion due to the increased mixing amount with glycerin as described later, and may also cause molding-related problems when manufacturing thermoplastic resin chips.

[0046] Furthermore, the hydroxyethyl cellulose can be mixed in a proportion of 65% to 80% by weight relative to the total weight of the hydroxyethyl cellulose and glycerol. If the content of the hydroxyethyl cellulose is less than 65% by weight, the excessive glycerol content may cause adhesion or make it difficult to perform granulation. Moreover, after plasticization, it may mix into a blocky form that is difficult to feed into extruders or other equipment. If it exceeds 80% by weight, the problem of not being able to manufacture a thermoplastic resin may occur because it is difficult to be sufficiently plasticized by glycerol.

[0047] The hydroxyethyl cellulose described above can be used as a commercially available product or manufactured in-house. As for the manufacturing method of hydroxyethyl cellulose, manufacturing methods known in the industry can be applied without restriction. Preferably, it can be manufactured by reacting cellulose with an alkalizing agent to obtain alkalized cellulose, and then subjecting the obtained alkalized cellulose to an etherification reaction.

[0048] In addition, glycerol can be obtained as a byproduct in the manufacture of soaps or fatty acids from natural resins, and more recently, it has been synthesized by treating propylene with chlorine to obtain epichlorohydrin, followed by hydrolysis. It has wide applications in various fields such as rubber, toothpaste, cosmetics, chemicals, coatings, cellophane, printing inks, and pastries.

[0049] In this invention, the glycerol can inhibit the strong hydrogen bonding caused by the hydroxyl groups of hydroxyethyl cellulose by mixing into hydroxyethyl cellulose, and create an environment conducive to micro Brownian motion by increasing the distance between cellulose polymer chains. It can be added at 20% to 35% by weight relative to the total weight of hydroxyethyl cellulose and glycerol.

[0050] When the glycerol content is less than 20% by weight relative to the total weight of hydroxyethyl cellulose and glycerol, the effect of creating an environment conducive to micro Brownian motion by inhibiting the strong hydrogen bonding caused by the hydroxyl groups of hydroxyethyl cellulose and increasing the distance between cellulose polymer chains may be negligible, resulting in the inability to lower the glass transition temperature and impart flexibility to the resin. When the content exceeds 35% by weight, excessive glycerol dissolution may cause adhesion and make it difficult to granulate into particles.

[0051] Next, a thermoplastic resin can be obtained by compounding and plasticizing the mixture of hydroxyethyl cellulose and glycerol [step (b)].

[0052] The mixing of the mixture can be performed at 50°C to 90°C at 300 rpm or higher, preferably at 70°C to 90°C at 300 rpm to 600 rpm, in order to easily achieve plasticization of hydroxyethyl cellulose. The mixing time can be adjusted appropriately according to the content of the mixture or the degree of plasticization, preferably 30 minutes to 60 minutes.

[0053] When the mixing is performed under the conditions described, the glass transition temperature and melting point can be reduced, thus facilitating the micro-Brownian motion of hydroxyethyl cellulose, thereby improving the plasticization efficiency of hydroxyethyl cellulose even with the use of a small amount of glycerol.

[0054] The mixing can be performed in any manner, either by a mixing machine alone or by an extruder in conjunction with the extrusion described later. In this case, the mixing machine is not subject to any particular limitation and can be any mixing machine commonly used in this industry; for example, it could be a high-speed mixer, a blender, or an agitator.

[0055] In addition, additives may be further mixed as needed before and / or after the mixing (plasticizing) step.

[0056] The additive is preferably selected from one or more of the group consisting of antioxidants, lubricants, biodegradation promoters and strength enhancers. It may use ingredients commonly used in the industry. The present invention does not impose any special restrictions on the selection of the additive.

[0057] Specifically, the antioxidant in the additive can prevent the thermal decomposition of hydroxycellulose during thermoplasticization and molding. It can be a general antioxidant that can be used in this industry. As an example, it can be a single or mixed form of tetrakis(methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)) and tris(2,4-di-t-butylphenyl) phosphate.

[0058] Furthermore, the lubricant used to enhance the lubrication properties of the thermoplastic resin can be any general lubricant that is applicable in the industry, without limitation. In terms of miscibility and lubricity with the thermoplastic resin of the present invention, it is preferably selected from one or more of the group consisting of sorbitol, magnesium stearate, calcium stearate, ethylene glycol, glyceryl monostearate and lecithin.

[0059] Furthermore, the biodegradation accelerator and strength reinforcing agent can be any general biodegradation accelerator and strength reinforcing agent that can promote the biodegradation of thermoplastic resin or enhance the strength of resin. As the biodegradation accelerator, it can be a single component or a mixture of two or more fatty oils such as soybean oil, castor oil, linoleic acid, lauric acid, oleic acid, and linoleic acid; fatty acids such as ethyl oleate, ethyl linoleate, and isooctyl ester; and as the strength reinforcing agent, it can be glass fiber and carbon fiber.

[0060] The additives described above can be selected in generally used amounts without limitation within the range that do not impair the target physical properties of the thermoplastic material of the present invention. Preferably, each additive can be 0.01 parts by weight to 10 parts by weight relative to 100 parts by weight of the thermoplastic resin of the present invention.

[0061] As described above, the compounded (plasticized) thermoplastic resin can be further processed into a form that is easy to commercialize by performing extrusion and cutting steps.

[0062] The extrusion step can be performed by an extruder, which is not subject to any special restrictions and can use any extruder commonly used in the industry. As an example, a single-screw extruder equipped with one screw or a multi-screw extruder equipped with multiple screws can be used. From the perspectives of uniform mixing of materials, ease of processing and economy, it is preferable to use a twin-screw extruder with two screws.

[0063] In order to effectively perform extrusion without causing the decomposition of the thermoplastic resin, the extruder temperature can be between 70°C and 200°C, preferably between 130°C and 180°C, and the extruder screw speed can be between 20 rpm and 300 rpm, preferably between 20 rpm and 200 rpm. With appropriate throughput per unit time under the extrusion conditions described above, sufficient extrusion can be achieved while ensuring excellent engineering efficiency, and it also has the advantage of not causing problems such as thermal decomposition of the resin components.

[0064] The extruded material can be easily processed by a granulator or similar equipment, and can also be cut into shapes that facilitate the manufacture of molded products, preferably in the form of granules or pellets.

[0065] Furthermore, in the steps of obtaining thermoplastic resin according to the present invention, it would be more effective to further include a cooling step by means of a cooling water tank between the extrusion and cutting steps, and it is preferable to perform a drying step of drying at 50°C to 80°C for 4 to 8 hours after the cutting step.

[0066] As an example of a thermoplastic resin obtained in the manner described above, the tensile strength measured according to ASTM D638 can be 4.5 MPa to 6.5 MPa, the elongation can be 20 mm to 45 mm, and it has excellent mechanical properties and molding processability, as well as biodegradability.

[0067] Next, a soil conditioner is produced by granulating the obtained thermoplastic resin [step (c)].

[0068] The granulation may include an extrusion step and a cutting step of performing extrusion and cutting on the mixture as described above, thereby producing a form that is easy to productize.

[0069] The extrusion step can be performed by an extruder, which is not subject to any special restrictions and can use any extruder commonly used in the industry. As an example, a single-screw extruder equipped with one screw or a multi-screw extruder equipped with multiple screws can be used. From the perspectives of uniform mixing of materials, ease of processing and economy, it is preferable to use a twin-screw extruder with two screws.

[0070] In order to effectively perform extrusion without causing the soil conditioner to decompose, the extruder temperature can be between 70°C and 200°C, preferably between 130°C and 180°C, and the extruder screw speed can be between 20 rpm and 300 rpm, preferably between 20 rpm and 200 rpm. With appropriate throughput per unit time under the extrusion conditions described above, sufficient extrusion can be achieved while ensuring excellent engineering efficiency, and it also has the advantage of not causing problems such as thermal decomposition of resin components.

[0071] The extruded material can be easily processed by a granulator or similar equipment, and can also be cut into shapes that facilitate the manufacture of molded products, preferably in the form of granules or pellets.

[0072] Furthermore, in the manufacture of the soil conditioner according to the present invention, it is more effective to further include a cooling step by cold air drying between the extrusion and cutting steps, and it is preferable to perform a drying step at 50°C to 80°C for 4 to 8 hours after the cutting step.

[0073] The soil conditioner manufactured in the manner described above can have an average diameter of 1 mm to 7 mm, specifically 2 mm to 5 mm. Soil conditioners with an average diameter within this range can be easily sprayed into the soil, and due to their larger surface area per unit weight, they have the advantage of increasing water absorption.

[0074] Furthermore, according to the method for manufacturing an environmentally friendly soil conditioner according to the present invention, a porous inorganic material and / or a crosslinking agent can be further mixed into the mixture of hydroxyethyl cellulose and glycerol in step (a) or the thermoplastic resin of the mixture of p-ethyl cellulose and glycerol in step (c) to produce an environmentally friendly soil conditioner.

[0075] At this point, the porous inorganic material serves to aid in the absorption and release of moisture. It may contain 5 to 60 parts by weight, preferably 10 to 50 parts by weight, relative to 100 parts by weight of the mixture from step (a) or the thermoplastic resin from step (c). If the content is less than 5 parts by weight relative to 100 parts by weight of the mixture from step (a) or the thermoplastic resin from step (c), problems with moisture absorption and release may occur due to blocked moisture movement paths. If the content exceeds 60 parts by weight, it may lead to a decrease in the sustainability of moisture release, and excessive addition of porous inorganic material may cause problems with moldability after extrusion.

[0076] As the porous inorganic material, porous inorganic materials can be used without limitation. Specifically, it can be one or more selected from the group consisting of perlite, vermiculite, bentonite and zeolite, and more specifically, it can be perlite.

[0077] Furthermore, the crosslinking agent can be mixed into the mixture of step (a) or the thermoplastic resin of step (c), thereby increasing fluidity by lowering the extrusion temperature, minimizing the decrease in physical properties during moisture absorption, and enhancing moisture absorption capacity. The crosslinking agent can be mixed in amounts of 5 to 40 parts by weight, preferably 10 to 40 parts by weight, relative to 100 parts by weight of the mixture of step (a) or the thermoplastic resin of step (c). If the crosslinking agent content is less than 5 parts by weight, a decrease in moisture absorption and absorption rate may occur. If it exceeds 40 parts by weight, excessive crosslinking agent may prevent the formation of strands during extrusion.

[0078] As the crosslinking agent, any crosslinking agent capable of crosslinking thermoplastic resins can be used without limitation. Specifically, it can be one or more selected from the group consisting of citric acid, polyethylene glycol, and hexanediol, and more specifically, it can be citric acid. Citric acid is a natural substance, and therefore has the advantages of being non-toxic and more biodegradable.

[0079] The soil conditioner according to the present invention, manufactured in the manner described above, is biodegradable and has excellent molding, processing, and mechanical properties. Therefore, it can increase soil moisture retention while achieving soil granulation, pH adjustment, nutrient supply, and microbial incorporation. This not only creates optimal vegetation growth conditions but also increases biocarbon content through biodegradation.

[0080] It should be clarified that, in the process of describing the soil conditioner and its manufacturing method of the present invention, other conditions or devices not explicitly described may be appropriately selected within the scope of what is usually practiced in the industry and are not subject to special restrictions.

[0081] The invention will now be described in more detail through specific experimental examples. These examples are merely illustrative to aid in understanding the invention, and their scope is not limited thereto.

[0082] <Experimental Example 1-1>

[0083] 77g of hydroxyethyl cellulose (Lotte Precision Chemical, HEC B100K) with a viscosity of 100,000 cps was mixed with 23g of glycerol and plasticized by high-speed mixing at 300 rpm for 30 minutes. The mixture was then extruded using a twin-screw extruder with a screw speed of 30 rpm [main motor speed 200-250 rpm] at an average extruder temperature of 150°C to obtain a thermoplastic resin. Perlite was added to the obtained thermoplastic resin according to the amounts in Table 1 and mixed for 20 minutes. The mixture was then extruded using a twin-screw extruder with a screw speed of 30 rpm [main motor speed 200-250 rpm] at an average extruder temperature of 150°C to obtain a strip-shaped (3mm × 3mm) soil conditioner.

[0084] <Experimental Examples 1-2 to 1-14>

[0085] The soil conditioner was manufactured using the same method as in Experimental Example 1-1, except that the conditions in Table 1 below were changed to produce a strip-shaped soil conditioner.

[0086] <Experimental Example 1-15>

[0087] After mixing 74g of hydroxyethyl cellulose (Lotte Precision Chemical, HEC H200K) with 200,000 cps and 26g of glycerol to obtain a mixture, 10g of perlite was added to the mixture, followed by high-speed mixing at 300 rpm for 30 minutes to plasticize it. After plasticization, the mixture was extruded using a twin-screw extruder with a screw speed of 30 rpm [main motor speed of 200 rpm to 250 rpm] at an average extruder temperature of 150°C to obtain a strip-shaped (3mm × 3mm) soil conditioner.

[0088] <Experimental Example 1-16>

[0089] The soil conditioner was manufactured using the same method as in Experimental Examples 1-15, except that the conditions in Table 1 below were changed to produce strip-shaped soil conditioners.

[0090] <Experimental Examples 1-17 to 1-27>

[0091] The soil conditioner was manufactured using the same method as in Experimental Example 1-1, except that the conditions in Table 1 below were changed to produce a strip-shaped soil conditioner.

[0092] <Experimental Example 1-28>

[0093] After adding 10g of perlite to 100g of hydroxyethyl cellulose (Lotte Precision Chemical, HEC B100K) with a viscosity of 100,000cps and mixing for 20 minutes, the mixture was extruded using a twin-screw extruder with a screw speed of 30rpm [main motor speed of 200rpm~250rpm] at an average extruder temperature of 150°C, thereby obtaining a strip-shaped (3mm×3mm) soil conditioner.

[0094] [Determination of soil conditioner's formability, water absorption, and water release]

[0095] The properties of the soil conditioners prepared in Experimental Examples 1-1 to 1-28 were determined according to the method described below, and the results are shown in Table 1 below.

[0096] Determination methods

[0097] (1) Molding properties test: The flowability of the extruded material was evaluated by visual inspection immediately after extrusion. In Table 1, “good” is recorded when extrusion is easy and the extruded material is in good condition, and “poor” is recorded when extrusion is impossible.

[0098] (2) Measurement of water absorption: 100g of soil conditioner sample prepared by the experimental example was put into a plastic container and mixed with 1,500ml of water. After 60 minutes, the amount of water absorbed by the soil conditioner was calculated by formula 1 and recorded in Table 1.

[0099] Water absorption (g) = Weight of soil conditioner after moisture absorption (g) - [Weight of soil conditioner before moisture absorption (g) + Weight of plastic container (g)] .....(1)

[0100] (3) Measurement of moisture release: The soil conditioner after absorbing moisture was placed at 20°C and 60% humidity for 180 hours (7 days). The moisture release was measured using a balance in 12-hour increments. The results were calculated using Formula 2 and recorded in Table 1.

[0101] Water release (g / h) = [Weight of soil conditioner after moisture absorption (g) - Weight of soil conditioner after water release (g)] / 144 (h) ... (2)

[0102] [Table 1]

[0103]

[0104] As shown in Table 1, the soil conditioners in Experiments 1-1 to 1-19 exhibited good formability and sufficient water absorption and hourly water release. Conversely, when the hydroxyethyl cellulose content exceeded 65%–80%, the soil conditioners showed poor formability. Furthermore, when polyethylene glycol (PEG) was used as a plasticizer, the formability was good, but the water absorption and hourly water release were poor. When hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), and hydroxyethyl methylcellulose (HEMC) were used, the formability was poor.

[0105] <Experimental Example 2-1>

[0106] A mixture was obtained by adding 23g of glycerol to 77g of hydroxyethyl cellulose (Lotte Precision Chemical, HEC B100K) with a viscosity of 100,000cps. Then, 5g of citric acid, a crosslinking agent, was added to the obtained mixture and plasticized by high-speed mixing at 300rpm for 30 minutes. The mixture was then extruded using a twin-screw extruder with a screw speed of 30rpm [main motor speed of 200rpm to 250rpm] at an average extruder temperature of 130°C, thereby obtaining a strip-shaped (3mm × 3mm) soil conditioner.

[0107] <Experimental Examples 2-2 to 2-14>

[0108] The soil conditioner was manufactured using the same method as in Experimental Example 2-1, except that the conditions in Table 2 below were changed to produce a strip-shaped soil conditioner.

[0109] <Experimental Example 2-15>

[0110] A mixture was obtained by adding 26g of glycerol to 74g of hydroxyethyl cellulose (Lotte Precision Chemical, HEC H200K) with a viscosity of 200,000cps. After plasticizing the mixture by high-speed mixing at 300rpm for 30 minutes, it was extruded using a twin-screw extruder with a screw speed of 30rpm [main motor speed of 200rpm-250rpm] at an average extruder temperature of 150°C, thereby obtaining a thermoplastic resin. After adding citric acid as a crosslinking agent to the obtained thermoplastic resin according to the amounts in Table 2 and mixing for 20 minutes, it was extruded using a twin-screw extruder with a screw speed of 30rpm [main motor speed of 200rpm-250rpm] at an average extruder temperature of 130°C, thereby obtaining a strip-shaped (3mm × 3mm) soil conditioner.

[0111] <Experimental Examples 2-16 and 2-17>

[0112] The soil conditioner was manufactured using the same method as in Experimental Examples 2-15, except that the conditions in Table 2 below were changed to produce strip-shaped soil conditioners.

[0113] <Experimental Examples 2-18 to 2-27>

[0114] The soil conditioner was manufactured using the same method as in Experimental Example 2-1, except that the conditions in Table 2 below were changed to produce a strip-shaped soil conditioner.

[0115] <Experimental Example 2-28>

[0116] After adding 25g of citric acid to 100g of hydroxyethyl cellulose (Lotte Precision Chemical, HEC B100K) with a viscosity of 100,000cps and mixing for 20 minutes, the mixture was extruded using a twin-screw extruder with a screw speed of 30rpm [main motor speed of 200rpm~250rpm] at an average extruder temperature of 130°C, thereby obtaining a strip-shaped (3mm×3mm) soil conditioner.

[0117] [Determination of soil conditioner's formability, water absorption, and water release]

[0118] The properties of the soil conditioners prepared in Experimental Examples 2-1 to 2-28 were determined according to the method described below, and the results are shown in Table 2 below.

[0119] Determination methods

[0120] (1) Molding properties test: The flowability of the extruded material was evaluated by visual inspection immediately after extrusion. In Table 2, “good” is recorded when extrusion is easy and the extruded material is in good condition, and “poor” is recorded when extrusion is impossible.

[0121] (2) Determination of water absorption: 100g of soil conditioner sample prepared by the experimental example was put into a plastic container and mixed with 1,500ml of water. After 60 minutes, the amount of water absorbed by the soil conditioner was calculated by formula 3 and recorded in Table 2.

[0122] Water absorption (g) = Weight of soil conditioner after moisture absorption (g) - [Weight of soil conditioner before moisture absorption (g) + Weight of plastic container (g)] .....(3)

[0123] (3) Measurement of moisture release: The soil conditioner after absorbing moisture was placed at 20°C and 60% humidity for 180 hours (7 days). The moisture release was measured using a balance in 12-hour increments. The results were calculated using Formula 4 and recorded in Table 2.

[0124] Water release (g / h) = [Weight of soil conditioner after moisture absorption (g) - Weight of soil conditioner after water release (g)] / 144 (h) ... (4)

[0125] [Table 2]

[0126]

[0127] As shown in Table 2, the soil conditioners of Experiments 2-1 to 2-20 exhibited good formability and sufficient water absorption and hourly water release. Conversely, when the hydroxyethyl cellulose content exceeded 65 wt% to 80 wt%, the formability was poor. Furthermore, when polyethylene glycol was used as a plasticizer, the formability was good, but the water absorption and hourly water release were poor. When hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), and hydroxyethyl methylcellulose (HEMC) were used, the formability was poor.

[0128] This confirms that the soil conditioner according to the present invention can enhance soil moisture retention and increase biochar content through biodegradation, thereby mitigating global warming.

[0129] As described above, although the present invention has been illustrated with limited experimental examples and accompanying drawings, the present invention is not limited thereto. Those skilled in the art to which this invention pertains can make various modifications and variations within the scope of the technical concept of the present invention and the appended claims.

Claims

1. An environmentally friendly soil conditioner, characterized in that: It contains a thermoplastic resin with 65% to 80% by weight of hydroxyethyl cellulose and 20% to 35% by weight of glycerol.

2. The environmentally friendly soil conditioner according to claim 1, characterized in that: The environmentally friendly soil conditioner also contains 5 to 60 parts by weight of porous inorganic material relative to 100 parts by weight of thermoplastic resin, or 5 to 40 parts by weight of crosslinking agent relative to 100 parts by weight of thermoplastic resin.

3. The environmentally friendly soil conditioner according to claim 2, characterized in that: The porous inorganic material is one or more selected from the group consisting of perlite, vermiculite, bentonite and zeolite.

4. The environmentally friendly soil conditioner according to claim 2, characterized in that: The crosslinking agent is one or more selected from the group consisting of citric acid, polyethylene glycol, and hexanediol.

5. The environmentally friendly soil conditioner according to claim 1, characterized in that: The viscosity of an aqueous solution of hydroxyethyl cellulose dissolved in water at 2% by weight was measured at 20°C using a Brookfield viscometer and ranged from 10 cps to 250,000 cps.

6. A method for manufacturing an environmentally friendly soil conditioner, characterized in that, include: Step (a) is to obtain the mixture by mixing 20% ​​to 35% glycerol with 65% to 80% hydroxyethyl cellulose; Step (b) involves kneading and plasticizing the obtained mixture to obtain a thermoplastic resin; and Step (c) involves granulating the obtained thermoplastic resin.

7. The method for manufacturing the environmentally friendly soil conditioner according to claim 6, characterized in that: In the method for manufacturing the environmentally friendly soil conditioner, a porous inorganic material and / or a crosslinking agent are further added and mixed in step (a) or step (c). The content of the porous inorganic material is 5 to 60 parts by weight relative to 100 parts by weight of the mixture in step (a) or 100 parts by weight of the thermoplastic resin in step (c). The content of the crosslinking agent is 5 to 40 parts by weight relative to 100 parts by weight of the mixture in step (a) or 100 parts by weight of the thermoplastic resin in step (c).

8. The method for manufacturing the environmentally friendly soil conditioner according to claim 7, characterized in that: The porous inorganic material is one or more selected from the group consisting of perlite, vermiculite, bentonite and zeolite.

9. The method for manufacturing the environmentally friendly soil conditioner according to claim 7, characterized in that: The crosslinking agent is one or more selected from the group consisting of citric acid, polyethylene glycol, and hexanediol.

10. The method for manufacturing the environmentally friendly soil conditioner according to claim 6, characterized in that: The viscosity of an aqueous solution of hydroxyethyl cellulose dissolved in water at 2% by weight was measured at 20°C using a Brookfield viscometer and ranged from 10 cps to 250,000 cps.

11. The method for manufacturing the environmentally friendly soil conditioner according to claim 6, characterized in that: The mixing in step (b) is performed at 50°C to 90°C at 300 rpm or higher.

12. The method for manufacturing the environmentally friendly soil conditioner according to claim 6, characterized in that: The granulation in step (c) is to pressurize and mold it into a granular state in the form of particles or pellets.

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