KR20200031471A - Photodegradable capsules for controlled release fertilizers and controlled release fertilizers comprising the same - Google Patents

Abstract

The present invention relates to an elution-controlled coating fertilizer comprising a photodegradable capsule containing poly (alkylene glycol of 1 to 3 carbon atoms) in which 2 or more of unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof are introduced as an additive, More specifically, poly (C1 to C1) having 2 or more of unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof introduced to disperse the photocatalyst to increase the photolysis efficiency of the photocatalyst in order to solve the problem of the residual capsule after elution. (3) alkylene glycol) and a photocatalyst containing a fertilizer in a photodegradable capsule, a dissolution-controlled coating fertilizer, and a method of manufacturing the same, which has the advantage of being environmentally friendly by increasing the photolysis efficiency of an excellent photocatalyst.

Description

Photodegradable capsules for controlled release fertilizers and controlled release fertilizers comprising the same}

The present invention relates to a photodegradable capsule for elution-controlled fertilizers and an elution-controlled coating fertilizer comprising such photodegradable capsules, and more specifically, an unsaturated car of 10 to 25 carbon atoms as an additive to solve the problem of residual capsules after elution. Dissolution-controlled coating fertilizer in the form of fertilizer contained in a photodegradable capsule containing a photocatalyst having an increased photodegradation rate using poly (alkylene glycol having 1 to 3 carbon atoms) in which two or more carboxylic acids or derivatives thereof are introduced, and the same It relates to a manufacturing method.

Various dissolution control fertilizers have been developed for the purpose of enhancing the fertilization or expressing the effect of fertilizer according to the growth of plants.

In these controlled release fertilizers (CRF), fertilizer components such as nitrogen, phosphorus, and potassium are gradually supplied to crops for a long time. Conventional fertilizers that are sprayed in water or sprayed in powder form are usually difficult to sustain for more than 20 days once applied. This is because it is difficult for the crop to absorb the fertilizer component because it is washed out in the rain or penetrates deep into the ground. Due to this problem, the fertilizer is frequently applied in an excessive amount. Dissolution-controlled fertilizers reduce the release rate of fertilizer components with polymer capsules to compensate for these general fertilizer shortcomings, so that they are released for a long period of time. The polymer capsule is made of an olefin-based resin, a urethane-based resin, a latex, an acrylic resin, and the like, and after the fertilizer component melts while water vapor penetrates through the capsule, it is released through the capsule according to the osmotic pressure principle. The rate of penetration of water and fertilizer components varies depending on the ingredients and the thickness of the capsules. This can be used to control the rate at which the fertilizer component comes out. The period during which the fertilizer component is released from the capsule can be adjusted from a minimum of 30 days to a maximum of 2 years. However, after the fertilizer is released, the capsule polymer does not decompose and remains in the soil or river. In order to solve this problem, attempts have been made to use a biodegradable polymer as a capsule material, but since the biodegradable polymer has a rapid moisture permeation and decomposes by microorganisms between 1 and 6 months, the fertilizer component is at least 2 to 1 month. Not suitable for use in CRFs that have to be released over the years. In addition, in order to overcome the disadvantages of using only the biodegradable polymers listed above, when a non-degradable polymer such as an olefin resin and a biodegradable polymer are mixed and coated, the non-degradable polymer eventually has a disadvantage.

In order to solve this problem, an elution-controlled fertilizer using a photodegradable polymer has been recently proposed. For example, Chinese Patent No. 103588561 suggests that when hydrophilic titanium dioxide (TiO ₂ ) is used, the photolysis rate is lower than that of hydrophobic titanium dioxide. However, hydrophobic titanium dioxide has a disadvantage that it is more expensive than hydrophilic titanium dioxide.

Under this background, the problem to be solved by the present invention is to satisfy the dissolution control properties and productivity required for the dissolution-control fertilizer as described above, while improving the photolysis efficiency of the photocatalyst that has not been surface-treated to solve the problem of residual capsules. It is an object to provide an increased dissolution control coating fertilizer and a method for manufacturing the same.

As one aspect for achieving the above object, the present invention,

A polyolefin-based polymer, ethylene vinyl acetate, a photodegradable capsule (1) comprising poly (alkylene glycol having 1 to 3 carbon atoms) and photocatalyst having 2 or more of unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof as an additive; And

It relates to a dissolution controlled fertilizer comprising a fertilizer (2) contained in a space surrounded by the photodegradable capsule. Preferably, in the photodegradable capsule (1), the additive may be arranged so that the PEG is directed toward the photocatalyst to surround the photocatalyst.

The dissolution-controlled coating fertilizer according to the present invention is a polycatalyst in which an unsaturated carboxylic acid having 10 to 25 carbon atoms or a derivative thereof is introduced at least 2 as an additive (alkylene glycol having 1 to 3 carbon atoms) is used as an additive. By increasing the photodecomposition efficiency, by improving the problem of decomposition of capsules, which is a problem in conventional dissolution-controlled fertilizers, it promotes rapid decomposition of polymer capsules after fertilizer release, and has an environmentally friendly effect.

1 is a conceptual diagram briefly showing technical features of the present invention.

Hereinafter, the present invention will be described in detail.

The dissolution-control fertilizer according to the present invention is a polyolefin-based and ethylene vinyl acetate-based polymer, poly (unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof, or poly (alkylene glycols having 1 to 3 carbon atoms) and photocatalysts) having 2 or more introduced therein. It is characterized by including fertilizer in a space surrounded by a photodegradable capsule (1), which has increased photolysis efficiency by improving the efficiency of the photocatalyst by improving the dispersibility of the photocatalyst.

The polyolefin-based polymer may be high or low density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, polybutene, butene-ethylene copolymer, butene-propylene copolymer, and preferably low density polyethylene. In the present invention, the ethylene vinyl acetate copolymer is a copolymer comprising ethylene and vinyl acetate, and the content and molecular weight of the vinyl acetate are not particularly limited.

In a preferred embodiment, the polyolefin (LDPE, MI (melt index): 7 to 9, D (density): 0.90 to 0.95) and ethylene vinyl acetate (MI (melt index): 1 to 3, D (density): 0.90 to The polymer containing 0.96) may be included in an amount of 15 to 80 parts by weight, preferably 30 to 60 parts by weight, relative to the total weight of the coating layer. In addition, the weight ratio of polyolefin and ethylene vinyl acetate is 1: 1 to 6: 1 as polyolefin: ethylene vinyl acetate.

In addition, since the photocatalyst contained in the photodegradable capsule 1 acts as a catalyst only while receiving sunlight, while the fertilizer is released in the soil where sunlight is blocked, the polymer capsule is gradually released during the elution period while the polymer capsule is not decomposed. Is done. After the fertilizer is eluted, capsules exposed to the topsoil by plowing, etc., begin to decompose by sunlight.

The photocatalyst may be titanium dioxide (TiO ₂ ), zinc oxide (ZnO), or a mixture thereof, but is not limited thereto. Preferably, the photocatalyst may be in the form of nanoparticles having a primary particle having an average particle diameter of 5 to 50 nm. If the particle size of the photocatalyst is less than 5 nm, it is difficult to synthesize, and if it is more than 50 nm, there is a problem in that the specific surface area is increased and the photocatalyst efficiency is deteriorated. It may be included in 0.01 to 5 parts by weight.

The present invention is an additive for increasing the photodegradation efficiency of a photocatalyst that is not surface-treated, and includes poly (10 to 25 alkylene glycols of 1 to 3 carbon atoms) with an unsaturated carboxylic acid having 10 to 25 carbon atoms or a derivative thereof. It is characterized by. Examples of poly (alkylene glycols having 1 to 3 carbons) in which 2 or more of the unsaturated carboxylic acids having 10 to 25 carbons or derivatives thereof are introduced are preferably poly (ethylene glycol) dioleate. However, it is not limited thereto. Preferably, when the poly carboxylic acid having 10 to 25 carbon atoms or a derivative thereof (2 or more alkylene glycols having 1 to 3 carbon atoms) is included in the photodegradable capsule, titanium dioxide (TiO) in the coating solution _By improving the particle dispersion of the photocatalyst such as ₂ ), the decomposition efficiency of the photocatalyst is remarkably increased, and it has very desirable characteristics as an elution-controlled fertilizer.

In the present invention, when using a poly (alkylene glycol having 1 to 3 carbon atoms) in which 2 or more of the unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof are introduced, the photocatalyst exhibits excellent dispersion in the coating layer, thereby improving particle dispersion. It is characterized in that the decomposition efficiency of the photocatalyst is significantly increased. Specifically, since the solvent used in the photocatalyst dispersion is an organic solvent and is hydrophobic, agglomerates are generated when the photocatalyst is to be dispersed therein, and according to the prior art, the particle size of such agglomer is very large and not uniform. In the case of preparing a photocatalyst dispersion by using poly (an alkylene glycol having 1 to 3 carbon atoms) in which 2 or more of unsaturated carbon carboxylic acids having 10 to 25 carbon atoms or derivatives thereof are introduced as additives, as in the present invention, the particle size is remarkably When it is small and uniformly dispersed and coated on the coating layer, it exhibits excellent photolysis efficiency due to the remarkable dispersion degree of the photocatalyst. Preferably, having such excellent dispersibility in the coating layer dissolves poly (alkylene glycols having 1 to 3 carbon atoms) in which 2 or more of unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof are introduced into an organic solvent such as tetrachloroethylene. It is formed by mixing the photocatalyst and adding a strong energy such as ultrasonic waves or a bead mill to prepare a photocatalyst dispersion, and then mixing the polyolefin with ethylene vinyl acetate and filler to adsorb on granular fertilizer. In the present invention, the photocatalyst dispersion is characterized in that the photocatalyst has a z-average dispersion particle size of 5 to 1200 nm, preferably about 50 to 1000 nm, and the dispersion particle size is maintained even in the coating layer.

  The poly (alkylene carbon 1 to 3 alkylene glycol) additive having 2 or more of the unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof may be included in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the photocatalyst. Preferably, the weight average molecular weight (Mw) of poly (alkylene glycol having 1 to 3 carbon atoms) in which 2 or more of the unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof is introduced is 120 to 4000, more preferably 500 to 2000.

In a preferred embodiment, in the dissolution-controlled fertilizer according to the present invention, a photocatalyst is dispersed in the photodegradable capsule, and the photocatalyst is a poly (carbon number 1) in which two or more unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof are added as the additive. It is characterized in that it is dispersed in a form surrounded by poly (alkylene glycols having 1 to 3 carbon atoms) in alkylene glycol).

In the present invention, the fertilizer may be various known fertilizers, for example, urea or complex fertilizers. In a preferred embodiment, the fertilizer of the present invention may be a granular core fertilizer having a granular form in order to be easily incorporated into a photodegradable capsule.

In addition, the dissolution-controlled coating fertilizer according to the present invention may further include a component included in a known dissolution-controlled fertilizer. For example, these components include, but are not limited to, fillers, amphiphilic polymers, and the like. The filler may be an inorganic or organic filler, and examples may include at least one selected from the group consisting of talc (talcum), bentonite, ocher, diatomaceous earth, silica, aluminosilicate, kaolin, starch, and carbon. In a preferred embodiment, the filler is 30 to 70% by weight, preferably 40 to 60% by weight of the total coating layer.

i) preparing a photocatalyst dispersion by dispersing a photocatalyst in an organic solvent to which a poly (an alkylene glycol having 1 to 3 carbon atoms) in which at least 2 to 25 carbon atoms of unsaturated carboxylic acid or a derivative thereof is introduced is added;

ii) preparing a composition for a photodegradable capsule comprising a polyolefin-based and ethylene-vinyl acetate-based polymer, a filler, and a photocatalyst dispersion prepared in step i); And

iii) comprising the step of coating the surface of the granular fertilizer core with the composition for photodegradable capsules prepared in step ii), relates to a method for producing a dissolution controlled fertilizer.

In addition, in the production method according to the present invention, in step i), an organic solvent, preferably an organic solvent such as tetrachloroethylene (TCE), having 2 to 25 carbon atoms of an unsaturated carboxylic acid or a derivative thereof is introduced 2 or more. After dissolving poly (alkylene glycol having 1 to 3 carbon atoms), the photocatalyst is mixed and dispersed using strong energy such as sonication or bead mill. The composition for photodegradable capsules can be prepared by stirring the photocatalyst dispersion of step i) with a polyethylene-based polymer and an ethylene-vinyl acetate-based polymer. Step iii) may also be performed by a known coating method, but is not limited thereto. All of poly (C1-C3 alkylene glycol), photocatalyst, polyolefin-based polymer, and ethylene-vinyl acetate-based copolymer in which 2 to 25 carbon atoms of unsaturated carboxylic acid or derivatives thereof are introduced are 2 or more. The same can be said.

Preferably, in step i), the dispersion particle size of the photocatalyst is prepared to have a dispersion particle size of 5 to 1000 nm using strong energy such as ultrasonication.

According to the manufacturing method of the present invention, when the photocatalyst is simply added to the solvent without adding an additive, unlike the present in the composition for coating in a large aggregate state, when the additive according to the present invention is used, the aggregate of the photocatalyst is uniform and less It exhibits a dispersed particle size and thus exhibits excellent photocatalytic decomposition efficiency.

Hereinafter, the present invention will be specifically described through Examples and Experimental Examples, but the following Examples and Experimental Examples are merely illustrative of the present invention, and the scope of the present invention is not interpreted to be limited to the following Examples and Experimental Examples. .

Examples and Comparative Examples: Preparation of coating-control fertilizers for elution control

In the case of Examples 1 to 2, poly (ethylene glycol) 400 dioleate (Example 1) or poly (ethylene glycol) 1000 diolate (Example 2) having a weight average molecular weight of 400 of poly (ethylene glycol) as an additive is used. After dissolving in organic solvent tetrachloroethylene and mixing TiO ₂ to apply ultrasonic waves to prepare a photocatalyst dispersion, the photocatalyst dispersion, polyethylene, ethylene vinyl acetate, and talc are mixed in a composition ratio according to Table 1 below, and the solid content concentration is 5 After uniformly stirring and mixing at 90 ° C. with tetrachloroethylene so as to be weight%, the mixed composition was applied to nitrogen fertilizer particles using a fluidized bed dryer to prepare an elution controlled coating fertilizer.

In the case of the comparative example, after mixing and uniformly stirring at 90 ° C. with tetrachloroethylene so that the solid content concentration is 5% by weight in the mixing ratio of the composition according to Table 1, the mixed composition is applied to the nitrogen fertilizer particles using a fluid bed dryer. Dissolution controlled coating fertilizer was prepared.

Composition of dissolution-controlled coating fertilizer (g) Comparative example Examples 1-2 LDPE 30 30 EVA 13 13 Talc 57 57 additive 0 0.09 Titanium dioxide (TiO ₂ ) 0.86 0.86

Experimental example  1: Comparison test for photolysis properties

The photodegradation properties were measured by the following method.

Specifically, 5 g of the coated fertilizer coated as described above was taken, and a pinhole was drilled one by one with a needle, and then the internal fertilizer was completely eluted, and then the decomposition evaluation was performed with the remaining coating film. The coating film was exposed to light at 50 ° C and 400w / m 2 using ATLAS 'Suntest CPS + equipment. The change in weight of the coating film was measured after a total of 4 weeks of exposure on a daily basis for 8 hours, and the photolysis rate was calculated by the following equation, and the results are shown in Table 2 ,.

Photolysis rate of dissolution-controlled coating fertilizer according to additives additive Photolysis rate (%) HLB Particle size (nm) Example 1 Poly (ethylene glycol) 400 diolate 48 ± 3 8 924 Example 2 Poly (ethylene glycol) 1000 diolate 46 ± 3 8 983 Comparative example - 34 ± 15 - 1.7 ~ 3.2 x10 ⁴

As can be seen in Table 2, in the case of preparing the coating fertilizer as a comparative example, the dispersion particle size of the photocatalyst aggregate is large and the coating fertilizer does not exhibit a uniform particle size, whereas the additive according to the present invention has 10 to 25 carbon atoms. Coating with a coating composition comprising poly (ethylene glycol) 400 dioleate and poly (ethylene glycol) 1000 dioleate corresponding to poly (alkylene glycol having 1 to 3 carbon atoms) in which two or more unsaturated carboxylic acids or derivatives thereof are introduced In the case of one fertilizer, it was confirmed that the photocatalyst dispersion and the coating composition exhibited an excellently increased dispersion degree not only in the coating layer, but accordingly, a significant increase in the photolysis rate of 10% or more compared to the comparative example without using these additives. .

As a result, when an unsaturated carboxylic acid having 10 to 25 carbon atoms or a derivative thereof having 2 or more carbons (alkylene glycol having 1 to 3 carbon atoms) is used as an additive for a coating film of a dissolution-controlled fertilizer according to the present invention, excellent light It is clear that due to the decomposition rate, the problem of decomposition of capsules, which is a problem in conventional dissolution-controlled fertilizers, can be improved.

Claims (13)

A polymer containing polyolefin and ethylene vinyl acetate, a photodegradable capsule comprising poly (alkylene glycol having 1 to 3 carbon atoms) and photocatalyst having 2 or more unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof as additives (1) ); And
Dissolution controlled fertilizer comprising a fertilizer (2) contained in a space surrounded by the photodegradable capsule. The method of claim 1, wherein the polyolefin-based polymer is one selected from the group consisting of high or low density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, polybutene, butene-ethylene copolymer and butene-propylene copolymer. The dissolution control fertilizer. The method of claim 1, wherein the polymer comprising the polyolefin and ethylene vinyl acetate is 15 to 80 parts by weight compared to 100 parts by weight of the total photodegradable capsule, dissolution-controlled fertilizer. According to claim 1, wherein the polyunsaturated carboxylic acid having 10 to 25 carbon atoms or a derivative thereof (2 or more alkylene glycols having 1 to 3 carbon atoms) is contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the photocatalyst. , Dissolution controlled fertilizer. The poly (ethylene glycol) dioleate of claim 1, wherein the poly (alkylene glycol having 1 to 3 carbon atoms) in which 2 or more of the unsaturated carboxylic acids having 10 to 25 carbon atoms or derivatives thereof are introduced is poly (ethylene glycol) dioleate. ), Dissolution controlled fertilizer. According to claim 1, The photocatalyst will be titanium dioxide (TiO ₂ ), zinc oxide (ZnO) or a mixture thereof, dissolution-controlled fertilizer. According to claim 6, Primary particles of the photocatalyst having a particle diameter of 5 to 50 nm, dissolution-controlled fertilizer. According to claim 1, The photocatalyst will be 0.01 to 10 parts by weight compared to 100 parts by weight of the total photodegradable capsule, dissolution-controlled fertilizer. The poly (alkyl having 1 to 3 carbons) in poly (alkylene having 1 to 3 carbons) in which 2 or more of the unsaturated carboxylic acids having 10 to 25 carbons or derivatives thereof are introduced in the photodegradable capsule. A dissolution-controlled fertilizer in which the renglycol) group is in a form surrounding the photocatalyst. According to claim 1, The photodegradable capsule is to further include a filler, dissolution controlled fertilizer. According to claim 1, The filler is talc (talcum), bentonite, ocher, diatomaceous earth, silica, aluminosilicate, kaolin, starch, and one or more selected from the group consisting of carbon, elution controlled fertilizer. The dissolution controlling fertilizer according to claim 1, wherein a dispersion particle size in the coating layer of the photocatalyst is 5 to 1200 nm. i) preparing a photocatalyst dispersion by dispersing a photocatalyst in an organic solvent to which a poly (an alkylene glycol having 1 to 3 carbon atoms) in which at least 2 to 25 carbon atoms of unsaturated carboxylic acid or a derivative thereof is introduced is added;
ii) preparing a composition for a photodegradable capsule comprising a polyolefin-based and ethylene vinyl acetate polymer, and the photocatalyst dispersion prepared in step i); And
iii) coating the surface of the granular fertilizer core with the composition for photodegradable capsules prepared in step ii).

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