Environmentally friendly soil conditioner and method for producing the same

Abstract

The present invention relates to a soil conditioner and a method for producing the same, and more specifically, to an environmentally friendly soil conditioner and a method for producing the same, which not only increases the water retention capacity of the soil, promotes soil aggregation, adjusts pH, supplies nutrients, and introduces microorganisms, thereby creating optimal vegetation conditions, but also increases the bio-carbon content while being biodegradable, thus reducing global warming.

Description

Technical Field

[0001] The present invention relates to a soil conditioner and a method for producing the same. More specifically, it can be mixed into natural or artificial soil to increase the water retention capacity in the soil, and while being biodegradable, it can increase the bio-carbon content, so it can reduce global warming. The present invention relates to an environmentally friendly soil conditioner and a method for producing the same.

Background Art

[0002] A soil conditioner generally refers to a substance used to improve the physical, chemical, and / or biological properties of problematic soils that affect plant growth / crop quality and safety due to natural / human influences.

[0003] Problematic soils include sandy soil, clay soil, structural obstacle soil, acidic soil, saline soil, alkaline soil, contaminated soil, etc. Such problematic soils mainly have insufficient vegetation, poor structure, hinder the growth of plant roots, have low fertility, and lack nutrients (imbalance, acidification, salinity, excessive or insufficient soil moisture, toxic substances, etc.).

[0004] In particular, among problematic soils, sandy soil mainly appears in dry areas and in soils where desertification is progressing. In dry areas, the soil is eroded by wind or concentrated rainfall, and the survival rate of planted trees and forests is low. Due to the characteristics of sandy soil, it does not retain water, so when the water in the soil drains out, the nutrient components in the soil are washed away together. The roots of plants such as trees or grass can utilize not only water but also nutrient components, making it difficult to form forests or grasslands.

[0005] In arid regions like these, attempts have been made to improve soil by adding hygroscopic polymers such as polyacrylic acid (ASAP; acrylic sodium salt polymer) or polyacrylamide to maintain soil moisture and prevent desertification (Patent Documents 1 and 2). However, organic matter, including fertilizers, is not effective in maintaining or improving soil moisture. Polyacrylamide, in particular, is classified as a secondary carcinogen and is harmful to health. Petroleum-based acrylics are major culprits in greenhouse gas emissions and should no longer be used to prevent environmental pollution.

[0006] On the other hand, inorganic salts such as magnesium chloride (MgC2) can help retain moisture in the soil, but especially in sandy soils, they dissolve easily in rainwater and are easily removed from the soil, flowing into river water and negatively impacting aquatic ecosystems such as rivers due to salt concentration. Furthermore, the use of excessive amounts of inorganic salts may cause environmental problems such as soil acidification and plant death.

[0007] Furthermore, hygroscopic polymers require a long time to decompose in the soil, and there is a risk that these polymers and / or their decomposition products may act as toxic components in the soil ecosystem, causing environmental pollution.

[0008] Therefore, in order to improve damaged soils and prevent sand formation in arid regions, there is a need for soil conditioners that do not use inorganic salts or polymers that cause soil toxicity as their main component, and that improve crop survival rates / productivity during afforestation or grassland formation, and agricultural activities in arid regions, by maintaining / improving soil moisture while preventing the leaching of fertilizer components from the soil and enhancing fertilizer effects. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Korean Registered Patent No. 10-1264829 (Publication Date: January 23, 2013) [Patent Document 2] Korean Registered Patent No. 10-2479792 (Publication Date: April 20, 2022) [Overview of the project] [Problems that the invention aims to solve]

[0010] The main objective of the present invention is to solve the above-mentioned problems, and to provide an environmentally friendly soil conditioner and a method for producing the same that can increase the water retention capacity of the soil and increase the bio-carbon content while being biodegradable, thereby reducing global warming. [Means for solving the problem]

[0011] To achieve the above objective, one embodiment of the present invention provides an environmentally friendly soil conditioner characterized by containing a thermoplastic resin containing 65% to 80% by weight of hydroxyethylcellulose and 20% to 35% by weight of glycerin.

[0012] In a preferred embodiment of the present invention, the environmentally friendly soil conditioner may further contain 5 to 60 parts by weight of a porous inorganic material per 100 parts by weight of a thermoplastic resin, or 5 to 40 parts by weight of a crosslinking agent per 100 parts by weight of a thermoplastic resin.

[0013] In a preferred embodiment of the present invention, the porous inorganic material may be one or more selected from the group consisting of perlite, vermiculite, bentonite, and zeolite.

[0014] In one preferred embodiment of the present invention, the crosslinking agent may be one or more selected from the group consisting of citric acid, polyethylene glycol, and hexanediol.

[0015] In a preferred embodiment of the present invention, the hydroxyethyl cellulose may be characterized in that the viscosity of an aqueous solution prepared by dissolving it in 2% by weight in water is measured at 20°C using a Brookfield viscometer to 10 cps to 250,000 cps.

[0016] Another embodiment of the present invention provides a method for producing an environmentally friendly soil conditioner, comprising the steps of (a) mixing 65% to 80% by weight of hydroxyethylcellulose with 20% to 35% by weight of glycerin to obtain a mixture, (b) kneading the obtained mixture to plasticize it to obtain a thermoplastic resin, and (c) granulating the obtained thermoplastic resin.

[0017] In another preferred embodiment of the present invention, the method for producing the environmentally friendly soil conditioner is to further add and mix a porous inorganic material and / or a crosslinking agent to step (a) or step (c), wherein the content of the porous inorganic material is 5 to 60 parts by weight per 100 parts by weight of the mixture in step (a) or 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 per 100 parts by weight of the mixture in step (a) or 100 parts by weight of the thermoplastic resin in step (c).

[0018] In another preferred embodiment of the present invention, the porous inorganic material may be characterized by being one or more selected from the group consisting of perlite, vermiculite, bentonite, and zeolite.

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

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

[0021] In another preferred embodiment of the present invention, the kneading in the step (b) can be characterized in that it is carried out at 50 °C to 90 °C at 300 rpm or more.

[0022] In another preferred embodiment of the present invention, the granulation in the step (c) can be characterized in that it is pressure-molded into a granular state such as granular or pellet-like.

Effects of the Invention

[0023] The environment-friendly soil conditioner according to the present invention can increase the water retention capacity in the soil, improve the drought and dry growth environment of crops, and increase the bio-carbon content as a biodegradable raw material, so that global warming can be reduced.

[0024] In addition, the environment-friendly soil conditioner according to the present invention is excellent in molding processability, easy to adjust the particle size, and can be bulk-sprayed or mechanically sprayed, so the laying work of the soil conditioner is simple, efficient in shortening the working time and saving the spraying cost, and has excellent water absorption and durability, so it can maintain a certain performance for a long time.

Brief Description of the Drawings

[0025] [Figure 1] Figures 1(a) and 1(b) are photographic images of the soil conditioners produced in Experimental Examples 1-3 and 1-4 of the present invention taken with a digital camera. [Figure 2] It is a photographic image of the soil conditioner produced in Experimental Example 2-3 of the present invention taken with a digital camera.

Modes for Carrying Out the Invention

[0026] The advantages, features, and methods for achieving them of the present invention will become clearer with reference to the experimental examples described in detail below, along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and can be realized in a variety of different forms. These embodiments are provided merely to complete the disclosure of the present invention and to fully inform those who are ordinary skill in the art to which the present invention pertains. The present invention is defined solely by the scope of the claims.

[0027] In describing the present invention, if it is determined that a specific description of related known technologies may obscure the gist of the present invention, such detailed description will be omitted.

[0028] Wherever "includes," "has," "consists of," or "is composed of" is used in this specification, other parts may be added unless "only" is used. When a component is expressed singularly, it includes cases where it includes multiple components unless otherwise explicitly stated.

[0029] The features of each of the various experimental examples of the present invention can be partially or entirely combined or linked with one another, enabling a variety of technically diverse interdependencies and drives, and each experimental example may be carried out independently of the others or together in relation to one another.

[0030] In one aspect, the present invention relates to an environmentally friendly soil conditioner characterized by containing a thermoplastic resin containing 65% to 80% by weight of hydroxyethylcellulose and 20% to 35% by weight of glycerin.

[0031] Generally, cellulose derivatives possess water retention, flame resistance, and pH stability, and are biodegradable. Recently, development of various soil conditioners has been progressing. However, they are composed of strong hydrogen bonds, and as thermal decomposition progresses below their melting point, they are difficult to mix with inorganic materials, crosslinking agents, and additives. Furthermore, they have a polymer structure that is difficult to mold and process, and have not been able to adequately fulfill their role as soil conditioners.

[0032] Therefore, in this invention, a thermoplastic resin is used, obtained by adding glycerin in a specific amount to hydroxyethyl cellulose, which has a specific viscosity, among cellulose derivatives. By further mixing porous inorganic materials and / or crosslinking agents to this resin and granulating it, it is possible to stably increase the water retention capacity in the soil, promote soil aggregation, adjust pH, supply nutrients, and introduce microorganisms. In addition, it is possible to increase the bio-carbon content while being biodegradable, the particle size of the product can be easily adjusted, which is advantageous for large-scale spraying using machinery such as drones and tractors, and an environmentally friendly soil conditioner that is biodegradable using plant-based and natural materials can be provided.

[0033] To avoid repetition, the explanation of each of the aforementioned components will be provided later in the description of the manufacturing method for the environmentally friendly soil conditioner.

[0034] From another perspective, the present invention relates to a method for producing an environmentally friendly soil conditioner, characterized by comprising the steps of (a) mixing 65% to 80% by weight of hydroxyethylcellulose with 20% to 35% by weight of glycerin to obtain a mixture; (b) kneading the obtained mixture to plasticize it to obtain a thermoplastic resin; and (c) granulating the obtained thermoplastic resin.

[0035] The method for producing an environmentally friendly soil conditioner according to the present invention first involves adding glycerin to hydroxyethylcellulose to obtain a mixture [(a) step].

[0036] The aforementioned hydroxyethyl cellulose (HEC) is a white or pale yellowish-white powdered water-soluble polymer component. Among cellulose derivatives, it possesses the best flame resistance and pH stability, as well as colloidal properties, water retention, and temperature resistance. It is recognized as a raw material that can be used in a wide variety of products across various industries.

[0037] In the present invention, the hydroxyethylcellulose is a base resin and may be hydroxyethylcellulose having 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 hydroxyethylcellulose is the viscosity measured at 20°C using a Brookfield viscometer in an aqueous solution of hydroxyethylcellulose dissolved in water (hydroxyethylcellulose: 2% by weight).

[0038] If the viscosity of the hydroxyethyl cellulose is less than 10 cps, the amount of glycerin mixed in, as described later, will increase, which may cause stickiness after extrusion and lead to moldability problems during the manufacture of thermoplastic resin chips.

[0039] Furthermore, the hydroxyethylcellulose can be mixed in an amount of 65% to 80% by weight relative to the total weight of hydroxyethylcellulose and glycerin. If the hydroxyethylcellulose content is less than 65% by weight, an excessive amount of glycerin may be present, resulting in stickiness, difficulty in the granulation process, and the mixture may form into a lump that is difficult to feed into equipment such as an extruder after plasticization. If it exceeds 80% by weight, there is a risk that plasticization by glycerin will not be sufficient, making it impossible to manufacture a thermoplastic resin.

[0040] Such hydroxyethyl cellulose can be used as a commercially available product or manufactured and used. Any known manufacturing method in the art is applicable without limitation as a method for producing hydroxyethyl cellulose. Preferably, cellulose can be reacted with an alkalizing agent to obtain alkalized cellulose, and then the obtained alkalized cellulose can be subjected to an etherification reaction.

[0041] On the other hand, glycerin can be obtained as a by-product when manufacturing soap or fatty acids from natural resins, but recently it is synthesized by treating propylene with chlorine to produce epichlorohydrin, which is then hydrolyzed. It is used in a variety of fields, including rubber, toothpaste, cosmetics, chemicals, paints, cellophane, printing inks, and confectionery.

[0042] In the present invention, the glycerin is mixed with hydroxyethylcellulose to interfere with the strong hydrogen bonding caused by the hydroxyl groups of hydroxyethylcellulose, thereby increasing the distance between cellulose polymer chains and creating an environment conducive to micro-Brownian motion. It can be added in an amount of 20% to 35% by weight relative to the total weight of hydroxyethylcellulose and glycerin.

[0043] If the glycerin content is added at a rate of less than 20% by weight relative to the total weight of hydroxyethylcellulose and glycerin, it will have little effect in interfering with the strong hydrogen bonding of the hydroxyl groups of hydroxyethylcellulose and widening the distance between cellulose polymer chains to create an environment conducive to micro-Brownian motion. It will not be able to lower the glass transition temperature or impart flexibility to the resin. If it exceeds 35% by weight, excessive glycerin may dissolve, causing stickiness and potentially making it difficult to form pellets or other granular materials.

[0044] Subsequently, the mixture of hydroxyethylcellulose and glycerin can be plasticized by kneading to obtain a thermoplastic resin [(b) step].

[0045] The kneading of the mixture can be carried out at 50°C to 90°C at 300 rpm or more, preferably at 70°C to 90°C at 300 rpm to 600 rpm, so that the hydroxyethylcellulose can be easily plasticized. The kneading time can be appropriately adjusted according to the content of the mixture or the degree of plasticization, preferably at 30 to 60 minutes.

[0046] When kneading is performed under the above conditions, the glass transition temperature and melting point can be lowered to facilitate micro-Brownian motion of hydroxyethylcellulose, thereby improving the plasticization efficiency of hydroxyethylcellulose even with a small amount of glycerin.

[0047] The aforementioned mixing can be carried out by any method, either by using a mixing machine alone or by using an extruder in conjunction with the extrusion described later. In this case, the mixing machine is not particularly limited and any mixing machine commonly used in this field can be used without restriction, such as a high-speed agitator, mixer, or blender.

[0048] Furthermore, additives may be added and mixed before and / or after the kneading (plasticizing) step, as needed.

[0049] The aforementioned additive may preferably be one or more selected from the group consisting of antioxidants, lubricants, biodegradation accelerators, and strength enhancers, and is a component commonly used in the field. The present invention does not particularly limit the selection of the aforementioned additive.

[0050] Specifically, the antioxidant in the additive plays a role in preventing thermal decomposition during the thermoplasticization and molding of hydroxyethylcellulose, and may be any ordinary antioxidant available in the field. For example, it may be tetrakismethylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane, tris(2,4-di-t-butylphenyl)phosphate, or other antioxidants, either alone or in mixture form.

[0051] Furthermore, the lubricant is intended to improve the lubrication properties of the thermoplastic resin, and any ordinary lubricant usable in the field can be used without limitation. In terms of miscibility with the thermoplastic resin of the present invention and lubricity, it may preferably be one or more selected from the group consisting of sorbitol, magnesium stearate, calcium stearate, ethylene glycol, glycerol monostearate, and lecithin.

[0052] Furthermore, the biodegradation accelerator and strength reinforcer can be any ordinary biodegradation accelerator and strength reinforcer that can promote the biodegradation of thermoplastic resins or reinforce the strength of the resin, and the biodegradation accelerator can be a fatty oil such as soybean oil, castor oil, linseed oil, sunflower oil, or coconut oil, fatty acids such as caproic acid, capric acid, lauric acid, oleic acid, olenic acid, or linoleic acid, or fatty acid esters such as ethyl oleate, ethyl linoleate, or isooctylate, either alone or in a mixture of two or more, and the strength reinforcer may be glass fiber, carbon fiber, etc.

[0053] Such additives can be selected without limitation in commonly used amounts, as long as they do not impair the desired physical properties of the thermoplastic resin of the present invention. Preferably, each additive may be independently present in amounts of 0.01 to 10 parts by weight per 100 parts by weight of the thermoplastic resin of the present invention.

[0054] As mentioned above, the kneaded (plasticized) thermoplastic resin can be obtained in a form that is easy to commercialize by further including an extrusion step and a cutting step of extruding and cutting.

[0055] The extrusion step can be carried out via an extruder, which is not particularly limited and can be any extruder commonly used in the field. For example, a single-screw extruder with one screw or a multi-screw extruder with multiple screws can be used. When considering uniform mixing of the material, ease of processing, and economics, it is preferable to use a twin-screw extruder with two screws.

[0056] In this case, the temperature of the extruder may be set to 70°C to 200°C, preferably 130°C to 180°C, so that extrusion can be carried out efficiently without decomposition of the thermoplastic resin, and the screw rotation speed of the extruder may be 20 rpm to 300 rpm, preferably 20 rpm to 200 rpm. Such extrusion conditions have the advantage of allowing sufficient extrusion with excellent process efficiency because the processing amount per unit time is appropriate, and does not cause problems such as thermal decomposition of resin components.

[0057] The extruded material can be easily handled via a pelletizer or the like, and can be cut into a form that facilitates the manufacture of molded products. Preferably, it may be in the form of granules or pellets.

[0058] Furthermore, in the step of obtaining the thermoplastic resin according to the present invention, it is also effective to further include a cooling step in which the resin is cooled through a cooling water bath between the extrusion and cutting steps, and it is preferable to perform a drying step after the cutting step in which the resin is dried at 50°C to 80°C for 4 to 8 hours.

[0059] The thermoplastic resin thus obtained may have a tensile strength of 4.5 MPa to 6.5 MPa as measured by ASTM D638, an elongation of 20 mm to 45 mm, excellent mechanical properties and moldability, and is biodegradable.

[0060] Subsequently, the obtained thermoplastic resin is granulated to produce a soil conditioner [(c) step].

[0061] The granulation process, which includes an extrusion step and a cutting step in which the aforementioned mixture is extruded and cut, can be obtained in a form that is easy to commercialize.

[0062] The extrusion step can be carried out via an extruder, which is not particularly limited and can be any extruder commonly used in the art. For example, a single-screw extruder with one screw or a multi-screw extruder with multiple screws can be used. When considering uniform mixing of the material, ease of processing, and economics, it is preferable to use a twin-screw extruder with two screws.

[0063] In this case, the temperature of the extruder may be set to 70°C to 200°C, preferably 130°C to 180°C, so that extrusion can be carried out efficiently without decomposition of the soil conditioner, and the screw rotation speed of the extruder may be 20 rpm to 300 rpm, preferably 20 rpm to 200 rpm. Such extrusion conditions have the advantage of allowing sufficient extrusion while being efficient in terms of process efficiency because the processing amount per unit time is appropriate, and without causing problems such as thermal decomposition of resin components.

[0064] The extruded material can be easily handled via a pelletizer or the like, and can be cut into a form that facilitates the manufacture of molded products. Preferably, it may be in the form of granules or pellets.

[0065] Furthermore, in the production of the soil conditioner according to the present invention, it is also effective to further include a cooling step via cold air drying between the extrusion and cutting steps, and it is preferable to perform a drying step after the cutting step, in which the soil is dried at 50°C to 80°C for 4 to 8 hours.

[0066] The soil conditioner manufactured in this manner may have an average diameter of 1 mm to 7 mm, and more specifically, an average diameter of 2 mm to 5 mm. Soil conditioners having an average diameter within the above range have the advantage of being easy to apply to the soil and having a large surface area per unit weight when absorbing water, which can increase the amount of water absorbed.

[0067] On the other hand, the method for producing an environmentally friendly soil conditioner according to the present invention involves further mixing a porous inorganic material and / or a crosslinking agent into a thermoplastic resin in which the mixture of hydroxyethylcellulose and glycerin from step (a) or the mixture of ethylcellulose and glycerin from step (c) has been plasticized, thereby producing an environmentally friendly soil conditioner.

[0068] In this case, the porous inorganic material plays a role in assisting the absorption and release of moisture, and may be included in amounts of 5 to 60 parts by weight, preferably 10 to 50 parts by weight, per 100 parts by weight of the mixture in step (a) or the thermoplastic resin in step (c). If it is included in amounts of less than 5 parts by weight per 100 parts by weight of the mixture in step (a) or the thermoplastic resin in step (c), the moisture transport pathway may be blocked, potentially causing problems with moisture absorption and release. If it is included in amounts exceeding 60 parts by weight, the sustained moisture release may decrease, and the addition of excessive porous inorganic material may cause problems with moldability after extrusion.

[0069] The porous inorganic material can be any porous inorganic material without limitation, and specifically, it may be one or more selected from the group consisting of perlite, vermiculite, bentonite, and zeolite, and more specifically, it may be perlite.

[0070] Furthermore, the crosslinking agent is mixed with the mixture in step (a) or the thermoplastic resin in step (c) to lower the extrusion temperature and increase flowability, minimize the deterioration of physical properties during water absorption, and increase water absorption capacity. It can be mixed in an amount of 5 to 40 parts by weight, preferably 10 to 40 parts by weight, per 100 parts by weight of the mixture in step (a) or the thermoplastic resin in step (c). If the amount of crosslinking agent is less than 5 parts by weight, there is a risk of problems occurring where the amount and rate of water absorption decreases, and if the amount exceeds 40 parts by weight, there is a risk of problems occurring where strands cannot be produced during extrusion due to an excess of crosslinking agent.

[0071] The aforementioned crosslinking agent can be applied without limitation as long as it is a crosslinking agent capable of crosslinking thermoplastic resins. Specifically, it may be one or more selected from the group consisting of citric acid, polyethylene glycol, and hexanediol, and more specifically, it may be citric acid. Since citric acid is a natural substance, it has the advantage of being non-toxic and even more favorable for biodegradation.

[0072] The soil conditioner produced according to the present invention in this manner is biodegradable, has excellent moldability and mechanical properties, and can stably increase the water retention capacity of the soil, as well as promote soil aggregation, pH adjustment, nutrient supply, and microbial incorporation, thereby creating optimal vegetation conditions. Furthermore, it can increase the bio-carbon content while being biodegradable.

[0073] In describing the soil conditioner and its manufacturing method of the present invention, it should be made clear that other conditions and equipment not explicitly mentioned can be appropriately selected within the range of practices commonly used in the art, and are not particularly limited. [Examples]

[0074] The present invention will be described in more detail below through specific experimental examples. The following experimental examples are merely illustrative to aid in understanding the present invention and do not limit its scope.

[0075] <Experimental Example 1-1> 77 g of hydroxyethyl cellulose (HEC B100K, manufactured by Lotte Fine Chemical Co., Ltd.) with a viscosity of 100,000 cps was mixed with 23 g of glycerin and plasticized by high-speed mixing at 300 rpm for 30 minutes. Then, a thermoplastic resin was obtained by extruding it using a twin-screw extruder with a screw speed of 30 rpm [main motor speed 200 rpm to 250 rpm] at an average extruder temperature of 150°C. Perlite was added to the obtained thermoplastic resin in the amounts shown in Table 1 and mixed for 20 minutes. Then, a strand-shaped (3 mm x 3 mm) soil conditioner was produced by extruding it using a twin-screw extruder with a screw speed of 30 rpm [main motor speed 200 rpm to 250 rpm] at an average extruder temperature of 150°C.

[0076] <Experimental Examples 1-2 to 1-14> The soil conditioner was manufactured in the same manner as in Experimental Example 1-1, but with the conditions shown in Table 1 below changed to produce a strand-shaped soil conditioner.

[0077] <Experimental Example 1-15> A mixture was obtained by mixing 74 g of hydroxyethyl cellulose (manufactured by Lotte Fine Chemical, HEC H200K) with a viscosity of 200,000 cps with 26 g of glycerin. After adding 10 g of perlite to the mixture, it was plasticized by high-speed mixing at 300 rpm for 30 minutes. The plasticized mixture was then extruded using a twin-screw extruder with a screw speed of 30 rpm [main motor speed 200 rpm to 250 rpm] at an average extruder temperature of 150°C to produce a soil conditioner in the shape of strands (3 mm x 3 mm).

[0078] <Experimental Example 1-16> The soil conditioner was manufactured in a strand shape using the same method as in Experimental Examples 1-15, but with the conditions shown in Table 1 below changed.

[0079] <Experimental Example 1-17-1-27> The soil conditioner was manufactured in the same manner as in Experimental Example 1-1, but with the conditions shown in Table 1 below changed to produce a strand-shaped soil conditioner.

[0080] <Experimental Example 1-28> To 100g of hydroxyethylcellulose (HEC B100K, manufactured by Lotte Fine Chemical Co., Ltd.) with a viscosity of 100,000 cps, 10g of perlite was added and mixed for 20 minutes. Then, the mixture was extruded using a twin-screw extruder with a screw speed of 30 rpm [main motor speed set to 200 rpm to 250 rpm] at an average extruder temperature of 150°C to produce a soil conditioner in the shape of strands (3 mm x 3 mm).

[0081] [Measurement of moldability, water absorption, and water release of soil conditioners] The properties of the soil conditioners produced in Experimental Examples 1-1 to 1-28 were measured using the following method, and the results are shown in Table 1 below.

[0082] Measurement method (1) Measurement of moldability: The flowability of the extruded material was visually evaluated immediately after extrusion. If extrusion was easy and the condition of the extruded material was good, it was recorded as "good" in Table 1; if it was not extruded, it was recorded as "poor" in Table 1.

[0083] (2) Measurement of moisture absorption: 100g of the soil conditioner test piece produced in the experimental example was placed in a plastic container, mixed with 1,500ml of water, and after 60 minutes, the amount of moisture absorbed by the soil conditioner was calculated using Equation 1 and is shown in Table 1.

[0084] Amount of moisture absorbed (g) = Weight of soil conditioner after moisture absorption (g) - [Weight of soil conditioner before moisture absorption (g) + Weight of plastic container (g)] ... (Equation 1)

[0085] (3) Measurement of moisture release: The soil conditioner after moisture absorption was left for 180 hours (7 days) at a temperature of 20°C and a humidity of 60%. The amount of moisture released was measured by weighing in 12-hour intervals, and then calculated using Equation 2, as shown in Table 1.

[0086] Moisture release rate (g / h) = [Weight of soil conditioner after moisture absorption (g) - Weight of soil conditioner after moisture release (g)] / 144 (h) ... (Equation 2) [Table 1]

[0087] As shown in Table 1, the soil conditioners in Experimental Examples 1-1 to 1-19 exhibited good moldability and sufficient water absorption and water release per unit time. In contrast, when the hydroxyethylcellulose content deviated from 65% to 80%, the moldability of the soil conditioners was found to be poor. Furthermore, when PEG was applied as a plasticizer, moldability was good, but water absorption and water release per unit time were found to be inferior. Additionally, when hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), and hydroxyethyl methylcellulose (HEMC) were applied, moldability was found to be poor.

[0088] <Experimental Example 2-1> A mixture was obtained by adding 23 g of glycerin to 77 g of hydroxyethyl cellulose (HEC B100K, manufactured by Lotte Fine Chemical Co., Ltd.) with a viscosity of 100,000 cps. 5 g of citric acid was added to the mixture as a crosslinking agent and the mixture was 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 rpm to 250 rpm] at an average extruder temperature of 130°C to produce a soil conditioner in the shape of strands (3 mm x 3 mm).

[0089] <Experimental Examples 2-2 to 2-14> The soil conditioner was manufactured in the same manner as in Experimental Example 2-1, but with the conditions shown in Table 2 below changed to produce a strand-shaped soil conditioner.

[0090] <Example 2-15> A mixture was obtained by mixing 74 g of hydroxyethyl cellulose (manufactured by Lotte Fine Chemical, HEC H200K) with a viscosity of 200,000 cps with 26 g of glycerin. This mixture was then plasticized by high-speed mixing at 300 rpm for 30 minutes, and then extruded using a twin-screw extruder with a screw speed of 30 rpm [main motor speed 200 rpm to 250 rpm] at an average extruder temperature of 150°C to obtain a thermoplastic resin. Citric acid was added to the obtained thermoplastic resin as a crosslinking agent in the amounts shown in Table 2, and after mixing for 20 minutes, the material was extruded using a twin-screw extruder with a screw speed of 30 rpm [main motor speed 200 rpm to 250 rpm] at an average extruder temperature of 130°C to produce a soil conditioner in the shape of strands (3 mm x 3 mm).

[0091] <Experimental Examples 2-16 and 2-17> The soil conditioner was manufactured in the same manner as in Experimental Example 2-15, but with the conditions shown in Table 2 below changed to produce a strand-shaped soil conditioner.

[0092] <Experimental Example 2-18-2-27> The soil conditioner was manufactured in the same manner as in Experimental Example 2-1, but with the conditions shown in Table 2 below changed to produce a strand-shaped soil conditioner.

[0093] <Experimental Example 2-28> To 100g of hydroxyethylcellulose (HEC B100K, manufactured by Lotte Fine Chemical Co., Ltd.) with a viscosity of 100,000 cps, 25g of citric acid was added and mixed for 20 minutes. Then, the mixture was extruded using a twin-screw extruder with a screw speed of 30 rpm [main motor speed set to 200 rpm to 250 rpm] at an average extruder temperature of 130°C to produce a soil conditioner in the shape of strands (3 mm x 3 mm).

[0094] [Measurement of moldability, water absorption, and water release of soil conditioners] The properties of the soil conditioner produced in Experimental Example 2-1-2-28 were measured using the following method, and the results are shown in Table 2 below.

[0095] Measurement method (1) Measurement of moldability: Immediately after extrusion, the flowability during extrusion was visually evaluated. If extrusion was easy and the condition of the extruded material was good, it was recorded as "good"; if it was not extruded, it was recorded as "poor" in Table 2.

[0096] (2) Measurement of moisture absorption: 100g of the soil conditioner test piece produced in the experimental example was placed in a plastic container, mixed with 1,500ml of water, and after 60 minutes, the amount of moisture absorbed by the soil conditioner was calculated using Equation 3 and is shown in Table 2.

[0097] Amount of moisture absorbed (g) = Weight of soil conditioner after moisture absorption (g) - [Weight of soil conditioner before moisture absorption (g) + Weight of plastic container (g)] ... (Equation 3)

[0098] (3) Measurement of moisture release: The soil conditioner after moisture absorption was left for 180 hours (7 days) at a temperature of 20°C and a humidity of 60%. The amount of moisture released was measured by weighing in 12-hour intervals, and then calculated using Equation 4, as shown in Table 2.

[0099] Moisture release rate (g / h) = [Weight of soil conditioner after moisture absorption (g) - Weight of soil conditioner after moisture release (g)] / 144 (h) ... (Equation 4) [Table 2]

[0100] As shown in Table 2, the soil conditioner in Experimental Example 2-1-2-20 exhibited good moldability, sufficient water absorption, and water release per hour. However, when the hydroxyethylcellulose content deviated from 65 wt% to 80 wt%, moldability was found to be poor. Furthermore, when polyethylene glycol was applied as a plasticizer, moldability was good, but water absorption and water release per hour were inferior. When hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), and hydroxyethyl methylcellulose (HEMC) were applied, moldability was found to be poor.

[0101] Therefore, it was confirmed that the soil conditioner according to the present invention can increase the water retention capacity of the soil and increase the bio-carbon content while being biodegradable, thereby reducing global warming.

[0102] As described above, although the present invention has been explained by limited experimental examples and drawings, it is understood that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical concept of the present invention and the following claims by persons with ordinary skill in the art to which the present invention pertains.

Claims

1. An environmentally friendly soil conditioner characterized by containing a thermoplastic resin containing 65% to 80% by weight of hydroxyethylcellulose and 20% to 35% by weight of glycerin.

2. The environmentally friendly soil conditioner according to claim 1, characterized in that it further contains 5 to 60 parts by weight of a porous inorganic material per 100 parts by weight of a thermoplastic resin, or further contains 5 to 40 parts by weight of a crosslinking agent per 100 parts by weight of a 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 hydroxyethyl cellulose has a viscosity of 10 cps to 250,000 cps when an aqueous solution of 2% by weight dissolved in water is measured at 20°C using a Brookfield viscometer.

6. (a) A step of obtaining a mixture by mixing 65% to 80% by weight of hydroxyethylcellulose with 20% to 35% by weight of glycerin, (b) A step of obtaining a thermoplastic resin by kneading the obtained mixture and plasticizing it, (c) A method for producing an environmentally friendly soil conditioner, comprising the step of granulating the obtained thermoplastic resin.

7. The method for producing the environmentally friendly soil conditioner, as described in claim 6, further involves adding and mixing a porous inorganic material and / or a crosslinking agent to step (a) or step (c), wherein the content of the porous inorganic material is 5 to 60 parts by weight per 100 parts by weight of the mixture in step (a) or 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 per 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 producing an 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 producing an 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 producing an environmentally friendly soil conditioner according to claim 6, characterized in that the hydroxyethyl cellulose has a viscosity of 10 cps to 250,000 cps when an aqueous solution of 2% by weight dissolved in water is measured at 20°C using a Brookfield viscometer.

11. The method for producing an environmentally friendly soil conditioner according to claim 6, characterized in that the kneading in step (b) is carried out at 50°C to 90°C at 300 rpm or more.

12. The method for producing an environmentally friendly soil conditioner according to claim 6, characterized in that the granulation in step (c) above is performed by press-molding into a granular or pellet-like state.

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