KR102308401B1 - Biodegradable release controlling fertilizer, biodegradable mulching film comprising the same and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a biodegradable release controlled fertilizer, a biodegradable mulching film comprising the same, and a method for manufacturing the same, and more particularly, by mixing a slow-release fertilizer with a biodegradable polymer resin capable of controlling the decomposition rate in an appropriate ratio, the type of crop and A biodegradable release control fertilizer capable of controlling the biodegradability rate according to the growth period and at the same time slowly decomposing the slow-release fertilizer component during biodegradation and permeating into the soil to improve soil fertility and activate the growth of crops, and biodegradability including the same It relates to a mulching film and a method for manufacturing the same.

Description

Biodegradable release control fertilizer, biodegradable mulching film containing same, and manufacturing method thereof

The present invention is a biodegradable release controlled fertilizer that can control the biodegradation rate according to the type and growth period of the crop, and can penetrate into the soil while slowly decomposing the slow-release fertilizer component during biodegradation to improve soil fertility and activate the growth of crops , to a biodegradable mulching film comprising the same and a method for manufacturing the same.

Farmers are mulching for the convenience of crop quality and management. Mulching refers to a crop cultivation method that covers the soil where crops are grown to prevent erosion of the soil and maintain moisture, control the temperature, and suppress weeds and germs to suppress weeding work or the use of herbicides. Materials used for mulching are various, such as vinyl, paper, non-woven fabric, rice straw, fallen leaves, bark (bark), and rice husk, but usually low-cost and convenient vinyl is widely used. Most of the mulching films use low-density polyethylene (LDPE)-based, non-degradable films.

However, such a difficult-to-decomposable film is not properly recovered after cultivating crops, and is a serious cause of farmland degradation due to illegal incineration and neglect. In addition, there are insufficient treatment facilities compared to the amount collected, and social costs are increasing due to the increase in the amount of accumulation.

Conventional Korean Patent Application Laid-Open No. 2005-0103546 discloses a polyethylene base resin selected from low-density polyethylene (LDPE), high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) for polyethylene mulching including Ti-based inorganic materials, carbon black, photodegradants and biodegradants. The film is disclosed. However, since the mulching film uses polyethylene as a base resin and a biodegradant is mixed with it as an additive, it is possible to decompose the biodegradant, but biodegradation of the polymer itself constituting the mulching film is impossible.

Recently, some biodegradable mulching films are being used voluntarily by each local government or by large-scale agricultural corporations (individuals). It was decomposed and there was a problem that the weed suppression effect fell. Also, in other regions, even when harvested in the fall, decomposition was slow and it was difficult to dispose of them.

On the other hand, the average annual temperature in Korea is 10~15℃, except for central and mountainous regions and islands, 23~26℃ in August, the hottest month, and -6~3℃ in January, the coldest month. The annual precipitation by region is 1200~1500mm in the central region and 1000~1800mm in the southern region. In addition, the Gyeongbuk area is 1000~1300mm, some areas along the Gyeongnam coast are around 1800mm, and the Jeju Island area is 1500~1900mm. Seasonally, 50-60% of the annual precipitation falls in summer. In addition, the wind is strong northwesterly in winter and southwesterly in summer, and seasonal winds are evident. In particular, the winds are relatively weak in September and October, and the influence of sea and land winds is evident in coastal areas. Humidity is in the range of 60-75% year-round nationwide, with July and August around 70-85%, and March and April 50-70%.

Existing biodegradable mulching film had a problem in that the degree of biodegradation was different depending on the regional climate variation in Korea, soil condition, crop type, severe climate change from year to year, and difference in precipitation. In addition, the soil was devastated and the growth of crops was affected, and crops were not able to grow properly.

Therefore, there is a need for a mulching film made of a new material that improves the growth of crops while selectively controlling the biodegradation rate according to the situation in consideration of the climate and soil environment conditions for each crop, region, and period.

Korean Patent Publication No. 2005-0103546

In order to solve the above problems, the present invention is to provide a biodegradable release controlled fertilizer capable of regulating the biodegradation rate depending on the crop and activating the growth of the crop by decomposing the slow-release fertilizer component during biodegradation. .

Another object of the present invention is to provide a biodegradable mulching film capable of controlling the biodegradation rate and increasing the growth rate and yield of crops.

Another object of the present invention is to provide a method for producing the biodegradable mulching film.

The object of the present invention is not limited to the object mentioned above. The objects of the present invention will become more apparent from the following description, and will be realized by means and combinations thereof described in the claims.

Most of the biodegradable mulching films produced and supplied in the past are based on PBAT (Polybutylene adipate terephthalate), which is the base resin, PLA (Polylactic acid), PBS (Poly Butylene Succinate) and TPS (Thermo Plastic Starch), inorganic substances, and various functional additives. It was prepared by mixing and the like. However, in this case, the mechanical properties are different and there is a difference in the degree and speed of decomposition, so it was difficult for the farmers who use it to select an appropriate biodegradable mulching film. In addition, if TPS, a plastic starch, was used for rapid decomposition, it was biodegraded at an early stage and did not play a sufficient role as mulching. In addition, there were problems such as the need to recover because the local temperature and climatic conditions were different, so that the decomposition was not carried out well, or the mulching function could not be performed due to the early decomposition and weeds grew.

Therefore, biodegradable biodegradable polymer resin that can selectively change the biodegradation rate according to regional (south, central, and northern) climate and soil environment, crops, and seasons is mixed with a slow-acting fertilizer that increases crop growth in an appropriate ratio. The present invention was completed by developing a sexual release control fertilizer and a mulching film containing the same. Here, the controlled release fertilizer (Controlled Release Fertilizer, CRF) refers to a fertilizer that slows fertilization by controlling dissociation of the fertilizer among the slow-release fertilizers by physical means. The controlled release fertilizer is also known as a time delay fertilizer or a sustained release fertilizer.

The biodegradable release controlled fertilizer according to the present invention is a biodegradable polymer resin capable of controlling the decomposition rate by mixing the slow-release fertilizer in an appropriate ratio, thereby controlling the biodegradability rate according to the type and growth period of the crop, and the slow-release fertilizer component is slowly decomposed during biodegradation. As it permeates into the soil, it can improve soil fertility and activate the growth of crops.

The biodegradable mulching film according to the present invention can control the biodegradability rate according to the type and growth period of the crop by adjusting the acid value of the biodegradable polymer resin, and the slow-acting fertilizer component is slowly decomposed in the soil to increase the growth rate and yield of crops. can be increased With the development of agricultural technology and the length of the growing period for crops, it is possible to prevent the deterioration of rural areas and illegal disposal due to the use of products made of non-degradable resin. It is not necessary, so the national and social cost can be reduced. In addition, it can contribute to the reduction of microplastics or microbeads, which have recently become an issue.

The biodegradable mulching film according to the present invention has biodegradability that can control the decomposition rate, so it is possible to reduce social costs due to the collection, recovery and treatment of mulching films, and to reduce the aging of the rural workforce, the avoidance of agriculture, and the decrease in the population of drunkenness. This can improve the poor agricultural environment and increase productivity. In addition, it is possible to prevent the devastation of farmland, and it has the advantage of securing the economic feasibility of rural areas by resolving the labor shortage caused by the aging of the rural population and reducing labor costs.

As described above, the present invention relates to a biodegradable release controlled fertilizer, a biodegradable mulching film comprising the same, and a method for manufacturing the same.

Specifically, the biodegradable release controlled fertilizer of the present invention is a biodegradable polymer resin 10 to 80% by weight; And 20 to 90% by weight of a slow-acting fertilizer; it may include, and an acid value of 0.1 to 5 KOH / g. The biodegradable release-controlled fertilizer has the advantage of controlling the release rate and release pattern of the nutrient component of the slow-release fertilizer by mixing the slow-release fertilizer with the biodegradable polymer resin in an appropriate ratio. In addition, the biodegradable release control fertilizer is a biodegradable rate is controlled by adjusting the acid value of the biodegradable polymer resin to release a slow-acting fertilizer component according to the type of crop and the growth period (for example, 3 months, 6 months, 8 months) You can adjust the timing. Due to this, the biodegradable release controlled fertilizer can increase the growth rate and yield of crops.

The biodegradable release controlled fertilizer may be prepared by mixing a slow-release fertilizer with a biodegradable polymer resin and then extruding it in the form of pellets. The biodegradable release control fertilizer can be adjusted so that the release of nutrients after fertilization can be delayed for a certain period of time, and as the biodegradation progresses by controlling the decomposition rate of the polymer, the necessary inorganic minerals can be released slowly. .

The biodegradable controlled release fertilizer has an acid value of 0.1-5 KOH/g, preferably 0.1-2.5 KOH/g, more preferably 0.2-1 KOH/g, most preferably 0.5 KOH/g it could be In this case, if the acid value is less than 0.1 KOH/g, the biodegradation rate is too delayed compared to the growth period of the crop, and there is a problem in that the release-controlled fertilizer is not decomposed even after the crop is harvested. On the other hand, if the acid value is more than 5 KOH/g, the biodegradation rate proceeds very quickly, so that it is decomposed before the sprouts of the crops appear, limiting the application range of the crops, and there is a limit in improving the soil and activating the growth of the crops.

The acid value is the amount of the acid component in the biodegradable release controlled fertilizer, and is a number expressed in g unit of the amount of potassium hydroxide (KOH: Potassium Hydroxide) required to neutralize the acid component of 1 g of the sample. Potassium hydroxide (KOH) may be further included for acid value control in the biodegradable release controlled fertilizer.

The biodegradable polymer resin used in the present invention may selectively use a resin having a certain level of tensile strength and tensile elongation while at the same time controlling the biodegradation rate. Specifically, the biodegradable polymer resin is polylactic acid (PLA), polybutylene adipate terephthalate [Poly (butylene adipate terephthalate), PBAT], polybutylene ethylene adipate succinate-co-terephthalate [ Poly(butylene ethylene adipate succinate-co-terephthalate), PBEAST], polybutylene succinate terephthalate [Poly(butylene succinate terephthalate), PBST], and poly(butylene ethylene adipate terephthalate), PBAT] at least one selected from the group consisting of may be used. Preferably, the biodegradable polymer resin may be polylactic acid, polybutyleneethylene adipate succinate-co-terephthalate, or a mixture thereof. Most preferably, a mixture of polylactic acid and polybutyleneethylene adipate succinate-co-terephthalate may be used. In this case, the mixture contains polylactic acid and polybutyleneethylene adipate succinate-co-terephthalate in a weight ratio of 6:2 to 7.5:0.5, preferably 6.5:1.5 to 7:1 by weight, most preferably 7: It may be a mixture of 1 weight ratio. The mixture is very excellent in controlling the biodegradation rate when mixing the polybutylene ethylene adipate succinate-co-terephthalate having biodegradability and easy adjustment of the acid value to polylactic acid having excellent biodegradability.

In particular, the polybutyleneethylene adipate succinate-co-terephthalate (PBEAST) may be prepared by synthesizing a difunctional glycol, an aliphatic ester acid and an aromatic ester acid by an esterification reaction or an transesterification reaction. The bifunctional glycol may be ethylene glycol having a tensile strength of 300 to 500 kg/cm 2 , an elongation of 200 to 400%, and a melting point of 90 to 120° C., 1,4-butanediol, or a mixture thereof. In addition, as the aliphatic ester acid and derivative, at least one selected from the group consisting of dimethyl succinate, adipic acid and succinic acid may be used. As the aromatic ester acid and derivative, at least one selected from the group consisting of dimethyl terephthalate, trimethyl trimellidate, dimethyl isophthalate, terephthalic acid, isophthalic acid and pyromellitic acid may be used. During the esterification reaction or transesterification reaction, 0.01 to 1.5 parts by weight of the catalyst and 0.02 to 1 parts by weight of the stabilizer may be mixed with respect to 100 parts by weight of the reactant. Tin normal butyl titanate may be mixed as the catalyst, and phosphorous acid may be mixed as the stabilizer.

The biodegradable polymer resin may have a number average molecular weight (Mn) of 30,000 to 100,000 g / mol, and a melting point of 50 to 180 ° C., preferably, a number average molecular weight (Mn) of 30,000 to 50,000 g / mol, It may have a melting point of 100 to 150 °C.

The biodegradable polymer resin may contain 10 to 80% by weight, preferably 65 to 80% by weight, more preferably 70 to 80% by weight, and most preferably 80% by weight based on the total content of the controlled release fertilizer. can If the content of the biodegradable polymer resin is less than 10% by weight, the polymer resin is rapidly decomposed and it may be difficult to control the release rate of the slow-release fertilizer for a desired period. Conversely, if the content of the biodegradable polymer resin is more than 80% by weight, the content of the polymer resin is higher than that of the slow-release fertilizer, so that the effect of improving the soil and activating the growth of crops cannot be expected. In addition, the slow biodegradation rate can cause problems with rotary operation after crop harvesting.

The slow-release fertilizer has a porous structure and has high nutrient adsorption, which can increase nutrient inefficiency, and a natural potassium component that does not leave salts can promote root development and harden fruits. In addition, by supplying various inorganic trace elements to crops, it exerts an excellent effect in resolving continuous cultivation disorders, and it can activate soil microorganisms with high far-infrared rays and negative ions. Specifically, the slow-release fertilizer is silicon dioxide (SiO ₂ ), potassium oxide (K ₂ O), aluminum oxide (Al ₂ O ₃ ), sodium oxide (Na ₂ O), magnesium oxide (MgO), ferric oxide (Fe ₂ O) ₃ ) and phosphoric acid (P ₂ O ₅ ) It may include one or more selected from the group consisting of. In addition, the slow-release fertilizer may further include one or more trace elements selected from the group consisting of cerium (Ce), lanthanum (La) and yttnium (Y), which are rare earth components effective for the growth of crops, in a very small amount.

The slow-release fertilizer may comprise 20 to 90% by weight, preferably 20 to 60% by weight, more preferably 20 to 40% by weight, and most preferably 20% by weight based on the total content of the controlled release fertilizer. . At this time, if the content of the slow-release fertilizer is less than 20% by weight, the effect of improving soil fertility or activating the growth of crops may be insignificant. Conversely, if the content of the slow-release fertilizer is more than 90% by weight, it may be difficult to selectively control the release rate of the slow-release fertilizer as the content of the biodegradable polymer resin is relatively small and the biodegradation proceeds rapidly.

Based on 100 parts by weight of the mixture of the biodegradable polymer resin and the slow release fertilizer, 0.01 to 0.3 parts by weight of a dispersant, 0.1 to 0.5 parts by weight of a slip agent, and 0.1 to 3 parts by weight of an antioxidant may be further included.

The dispersant may be mixed to increase the compatibility of the biodegradable polymer resin and the slow-release fertilizer. As the dispersant, at least one selected from the group consisting of octenyl succinic anhydride, dodecenyl succinic anhydride, hexadecenyl succinic anhydride and octadecenyl succinic anhydride may be used.

The dispersant may include 0.01 to 0.3 parts by weight, preferably 0.1 to 0.2 parts by weight, and most preferably 0.1 parts by weight based on 100 parts by weight of the mixture of the biodegradable polymer resin and the slow-release fertilizer. At this time, if the content of the dispersant is less than 0.01 parts by weight, the slow-release fertilizer may not be properly dispersed in the biodegradable polymer resin. Conversely, when the content of the dispersant exceeds 0.3 parts by weight, an improved compatibility effect cannot be expected any more when the biodegradable polymer resin and the slow-release fertilizer are mixed.

The slip agent processes the release control fertilizer and passes through the nip-roll step when forming the mulching film, and then the bubbles are compressed. The slip agent may be included to improve the slip properties of the mulching film. Specifically, the slip agent may be at least one selected from the group consisting of silica, diatomaceous earth, kaolin, and talc.

The slip agent may include 0.1 to 0.5 parts by weight, preferably 0.2 to 0.4 parts by weight, and most preferably 0.3 parts by weight based on 100 parts by weight of the mixture of the biodegradable polymer resin and the slow-release fertilizer. When the content of the slip agent is less than 0.1 parts by weight, the slip property of the mulching film may be insignificant during film forming by processing the release control fertilizer. If the content of the slip agent exceeds 0.5 parts by weight, further improved slip properties cannot be expected.

The antioxidant prevents crosslinking of the polymer resin when the biodegradable polymer resin and the slow-acting fertilizer are mixed, and may serve to have oxidation stability and decomposition rate suitable for each crop growth period. Specifically, the antioxidant may be phosphorus-based, phenol-based, or a mixture thereof. The phosphorus-based antioxidants include Bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite (SONGNOX® 6260), Tris(2, 4-di-tert-butylphenyl) phosphite (Tris(2,4-di-tert-butylphenyl) phosphite) (SONGNOX® 1680) and Poly(dipropylene glycol) phenyl phosphite (SONGNOX®DHOP) may be at least one selected from the group consisting of.

The phenolic antioxidant is octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (octadecyl-3-(3,5-di-tert-butyl-4- hydroxyphenyl) propionate) (SONGNOX® 1076), tetrakis[methylene(3,5-di-tert-butyl- 4-hydroxyphenyl)propionate methane) (SONGNOX® 1010) or a mixture thereof.

The antioxidant may include 0.1 to 3 parts by weight, preferably 1 to 3 parts by weight, and most preferably 2 parts by weight, based on 100 parts by weight of the mixture of the biodegradable polymer resin and the slow-release fertilizer. At this time, if the content of the antioxidant is less than 0.1, the antioxidant effect is insignificant, and the durability of the controlled release fertilizer may be reduced. Conversely, if the content of the antioxidant is more than 3 parts by weight, biodegradability may be reduced.

On the other hand, the biodegradable mulching film of the present invention may include the biodegradable release control fertilizer.

The biodegradable mulching film can control the biodegradability rate by adjusting the acid value of the biodegradable polymer resin, and the slow-release fertilizer component is slowly released during biodegradation, thereby increasing the growth rate and yield of crops.

The thickness of the biodegradable mulching film may be 12 to 50 μm, preferably 13 to 40 μm, more preferably 18 to 25 μm, and most preferably 18 μm. At this time, if the thickness of the mulching film is less than 12 μm, the biodegradation rate of the mulching film is very fast, so there is a problem in that the mulching film is biodegraded before harvesting and weeds grow abundantly. Conversely, if the thickness of the mulching film is more than 50 μm, the biodegradation rate is too slow, which may cause problems in rotary operation after crop harvesting, and there is a hassle of having to dispose of it.

In addition, the method for producing a biodegradable mulching film of the present invention comprises the steps of preparing a composition for a mulching film comprising the biodegradable release controlled fertilizer; and extruding the composition for a mulching film at a temperature of 110 to 180° C. to prepare a biodegradable mulching film.

The step of preparing the composition for the mulching film may be prepared by mixing additives as needed in the biodegradable release controlled fertilizer. As the additive, one or more kinds from the group consisting of pigments, lubricants, flame retardants, antistatic agents, heat stabilizers, light stabilizers and ultraviolet absorbers may be mixed. In particular, the pigment may be included to impart color to the mulching film, and specifically, carbon black, titanium dioxide, or a mixture thereof may be used.

In the step of preparing the mulching film, the mulching film may be manufactured by molding the composition for the mulching film using an extrusion molding machine. At this time, the molding temperature (ie, barrel temperature and die temperature) during film molding is 100 to 270 ° C., preferably 110 to 200 ° C., more preferably 110 to 170 ° C., most preferably 150 ° C. can In addition, during molding, the extrusion speed is 400-600 rpm, the raw material input speed is 50-200 rpm, and the roll speed can be manufactured under the conditions of 100-300 rpm. The main use of the mulching film may be an agricultural mulching film or a pot for hair growth, but is not limited thereto.

The biodegradable release controlled fertilizer according to the present invention is a biodegradable polymer resin capable of controlling the decomposition rate by mixing the slow-release fertilizer in an appropriate ratio, thereby controlling the biodegradability rate according to the type and growth period of the crop, and the slow-release fertilizer component is slowly decomposed during biodegradation. As it permeates into the soil, it can improve soil fertility and activate the growth of crops.

The biodegradable mulching film according to the present invention can control the biodegradability rate according to the type and growth period of the crop by adjusting the acid value of the biodegradable polymer resin, and the slow-acting fertilizer component is slowly decomposed in the soil to increase the growth rate and yield of crops. can be increased

The biodegradable mulching film according to the present invention has biodegradability that can control the decomposition rate, so it is possible to reduce social costs due to the collection, recovery and treatment of mulching films, and to reduce the aging of the rural workforce, the avoidance of agriculture, and the decrease in the population of drunkenness. This can improve the poor agricultural environment and increase productivity. In addition, it is possible to prevent the devastation of farmland, and it has the advantage of securing the economic feasibility of rural areas by resolving the labor shortage caused by the aging of the rural population and reducing labor costs.

The effects of the present invention are not limited to the above-mentioned effects. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 is a photograph showing a crop cultivation site when 0 days, 45 days, 85 days and 120 days have elapsed after coating of the biodegradable mulching film prepared in Example 11 according to the present invention.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the following examples.

Examples 1 to 9 and Comparative Examples 1 to 5: Preparation of biodegradable controlled release fertilizer

[Ingredients]

The biodegradable polymer resin has a number average molecular weight (Mn) of 30,000 to 70,000 g/mol and a melting point of 100 to 150 ℃ polybutylene ethylene adipate succinate-co-terephthalate (PBEAST) and polylactic acid (PLA) of the mixture was used. As a slow-acting fertilizer, natural Cari Miracle K (organic agricultural materials disclosure-1-3-271) containing the ingredients shown in Table 1 below and having a far infrared ray of 0.929 and anions of 600/cc was used. Octenyl succinic anhydride was used as a dispersant, and silica was used as a slip agent. Also, as the antioxidant, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite was used.

[Manufacturing method]

A mixture was prepared by mixing a biodegradable polymer resin, a slow release fertilizer, a dispersant, a slip agent, and an antioxidant at the mixing ratio shown in Table 2 below. Then, the mixture was extruded to prepare a biodegradable controlled release fertilizer in the form of pellets. At this time, a twin extruder having a screw diameter of 44 mm was used as the extruder, the extrusion speed was 300 rpm, the raw material input speed was 40 rpm, and the barrel temperature was 150 °C.

Experimental Example 1-1: Evaluation of biodegradability of biodegradable release controlled fertilizer

For the biodegradable release controlled fertilizers in Examples 1 to 9 and Comparative Examples 1 to 5, acid values and biodegradability in soil were confirmed in the following manner. The results are shown in Table 3 below.

[Assessment Methods]

(1) acid value

After dissolving 0.5 g of the biodegradable polymer resin in 20 ml of chloroform, the solution to which ethanol was added was titrated with 0.1N potassium hydroxide (KOH) in an automatic titrator to calculate the acid value.

(2) biodegradability

By measuring the aerobic biodegradability of plastics under KS M 3100-1 composting conditions, the amount of carbon dioxide generated in the standard sample (cellulose) and the test sample was measured and evaluated based on 6 months.

Biodegradability (%) = (amount of carbon dioxide generated / amount of theoretical carbon dioxide)*100

According to the results of Table 3, it was confirmed that Examples 1 to 9 had different degrees of biodegradation by adjusting the acid value according to the mixing ratio of the biodegradable polymer resin and the slow-release fertilizer. Through this, it was found that the release rate of the slow-release fertilizer component into the soil can be controlled by adjusting the acid value by controlling the mixing ratio of the two components.

On the other hand, in the case of Comparative Examples 1 and 2, when the biodegradable polymer resin and the slow release fertilizer are out of the mixing ratio, the acid value is too low by the biodegradable polymer resin, so that biodegradation hardly occurs, or conversely, the acid value is too high and the biodegradation proceeds quickly Confirmed. In addition, in the case of Comparative Examples 3 to 5, it was found that the acid value and the degree of biodegradation were affected according to the components of the biodegradable polymer resin and the mixing ratio thereof. However, in Comparative Examples 4 and 5, although the acid value and biodegradability showed an appropriate level, it was confirmed that the tensile strength and elongation did not satisfy the required physical property level of the film when the mulching film was manufactured using the same.

Experimental Example 1-2: Evaluation of growth change of pepper seedlings

The effect on the growth of pepper seedlings was confirmed with respect to the biodegradable release controlled fertilizer prepared in Example 8. ^{After fertilizing 110-130 g per 1 m 2} of the release-controlled fertilizer in the soil, the state of the pepper seedlings was checked at 15-day intervals. At this time, the untreated state in which no fertilizer was applied and the existing Miracle K fertilizer were used as controls. The results are shown in Tables 4 to 6 below.

According to the results of Tables 4 to 6, the biodegradable release-controlled fertilizer prepared in Example 8 showed that the pepper seedlings were gradually released into the soil for 45 days compared to the case of using untreated and general Miracle K fertilizers. It was confirmed that the growth of pepper seedlings was increased by supplying nutrients necessary for growth in a timely manner.

Examples 10-13 and Comparative Examples 6-7: Preparation of biodegradable mulching film

A composition for a biodegradable mulching film was prepared by mixing 6 parts by weight of carbon black as a pigment to 100 parts by weight of the biodegradable release controlled fertilizer prepared in Example 8. A mulching film was prepared by using the composition with a film molding machine (Daeryun Machinery Co., Ltd., model: 50 mm HD/PF FILM M/C). At this time, the barrel temperature of the film forming machine was 160 ℃, and the die temperature was 150 ℃. The extrusion speed was 500 rpm, the raw material input speed was 100 rpm, and the roll speed was 200 rpm to prepare a biodegradable mulching film. The thickness of the biodegradable mulching film was prepared differently as shown in Table 3 below.

Experimental Example 2: Evaluation of physical properties of biodegradable mulching film

The properties of the biodegradable mulching films prepared in Examples 10 to 13 and Comparative Examples 6 and 7 were evaluated in the following manner. The results are shown in Table 8 below.

[Assessment Methods]

(1) biodegradability

The degree of biodegradation was measured in the same manner as in Experimental Example 1.

(2) Tensile strength, tear strength and elongation

^{Tensile strength (Kgf/cm 2} ) and elongation (%) in the longitudinal direction (MD) and transverse direction (TD) of the mulching film at the time of breakage of the sample were measured according to the 7.6 tensile strength and elongation test method of KS M 3503.

According to the results of Table 8, in the case of Examples 10 to 13, it was confirmed that the mulching film had an appropriate degree of biodegradation of 72 to 93% while having excellent tensile strength and elongation required for the film depending on the film thickness of the film. In contrast, in Comparative Examples 6 and 7, when the film thickness was too thin, the biodegradability was as low as 50% or less, and when the film thickness was too thick, it was found that the biodegradability was as high as 99%.

Experimental Example 3: Evaluation of physical properties of biodegradable mulching film

The biodegradable mulching film prepared in Example 11 was coated on the soil of the Jeju Island region, and the decomposition progress of the coated mulching film was visually checked as the coating progressed for 4 months to evaluate the biodegradability. In this case, soybeans were used as the evaluation crop.

1 is a photograph showing the field of crop cultivation when 0 days, 45 days, 85 days and 120 days have elapsed after the coating of the biodegradable mulching film prepared in Example 11. According to the result of FIG. 1, it was confirmed that the film was coated without a torn part on the day of coating, and the film was coated without decomposition even after 45 days and 85 days, which are the periods in which crops are grown. In addition, it was confirmed that the film was gradually decomposed when the coating started 120 days after harvesting the crops. Through this, it can be seen that the mulching film prepared in Example 11 has mechanical properties to withstand external pressure during the period during which crops are being grown, and after 120 days of coating from which crops are harvested, mechanical properties are reduced and biodegradation occurs. It was found that the decomposition rate of the film can be controlled.

Claims (8)

Polylactic acid (PLA) and polybutylene ethylene adipate succinate-co-terephthalate [Poly (butylene ethylene adipate succinate-co-terephthalate), PBEAST] in a weight ratio of 6: 2 to 7.5: 0.5 Biodegradable polymer resin 10 to 80% by weight; And 20 to 90% by weight of a slow release fertilizer; containing, and an acid value of 0.1 to 5 KOH / g biodegradable release controlled fertilizer.
delete According to claim 1,
The biodegradable polymer resin has a number average molecular weight (Mn) of 30,000 ~ 100,000 g / mol, the melting point of the biodegradable release controlled fertilizer of 50 ~ 180 ℃.
According to claim 1,
The slow-release fertilizer is silicon dioxide (SiO ₂ ), potassium oxide (K ₂ O), aluminum oxide (Al ₂ O ₃ ), sodium oxide (Na ₂ O), magnesium oxide (MgO), ferric oxide (Fe ₂ O ₃ ) And phosphoric acid (P ₂ O ₅ ) Biodegradable release controlled fertilizer comprising at least one selected from the group consisting of.
According to claim 1,
The biodegradable release controlled fertilizer further comprising 0.01 to 0.3 parts by weight of a dispersant, 0.1 to 0.5 parts by weight of a slip agent, and 0.1 to 3 parts by weight of an antioxidant based on 100 parts by weight of a mixture of the biodegradable polymer resin and the slow release fertilizer.
A biodegradable mulching film comprising the biodegradable release controlled fertilizer of any one of claims 1 or 3 to 5.
7. The method of claim 6,
The thickness of the mulching film is a biodegradable mulching film of 12 ~ 50㎛.
Claims 1 or claim 3 to preparing a composition for a mulching film comprising the biodegradable release controlled fertilizer of any one of claims 1 to 5; and
Extruding the composition for the mulching film at a temperature of 100 to 270 ℃ to prepare a biodegradable mulching film;
A method for producing a biodegradable mulching film comprising a.

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