阅读说明：本技术 杀虫剂的微囊化 (Microencapsulation of insecticides ) 是由 张世玲 钟玲 任华 贠栋 陆威 常翠兰 于 2017-12-25 设计创作，主要内容包括：一种用于乳液中以形成本公开的微胶囊的有机/油混合物。所述有机/油混合物包括阿维菌素(abamectin)；非极性溶剂,所述非极性溶剂的汉森溶解度参数(Hansen solubility parameter)的极性(P)值为0至3；式I的极性溶剂：其中R<Sub>1</Sub>为C1至C15烷基；R2为H或C1至C8烷基；R<Sub>3</Sub>为C1至C15亚烷基；并且R<Sub>4</Sub>为C1至C15烷基,其中R<Sub>1</Sub>、R<Sub>2</Sub>、R<Sub>4</Sub>烷基和R<Sub>3</Sub>亚烷基中的碳的总和为8至30；和2.5至20重量％的异氰酸酯,其中每个重量％是按所述有机/油混合物的总重量计,并且所述阿维菌素、所述非极性溶剂、所述极性溶剂和所述异氰酸酯的重量％的总和总计为100重量％。<Image he="198" wi="700" file="DDA0002532238030000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(An organic/oil mixture for use in an emulsion to form the microcapsules of the present disclosure. The organic/oil mixture comprises abamectin (abamectin); a non-polar solvent having a polar (P) value of Hansen solubility parameter (Hansen solubility parameter) of 0 to 3; a polar solvent of formula I: wherein R is 1 Is a C1 to C15 alkyl group; r2 is H or C1 to C8 alkyl; r 3 Is a C1 to C15 alkylene group; and R is 4 Is C1 to C15 alkyl, wherein R 1 、R 2 、R 4 Alkyl and R 3 The sum of the carbons in the alkylene is 8 to 30; and 2.5 to 20 wt% of an isocyanate, wherein each wt% is based on the total weight of the organic/oil mixture and the sum of the wt% of the avermectin, the non-polar solvent, the polar solvent and the isocyanate totals 100 wt%.)

1. An organic/oil mixture comprising:

0.1 to 20 weight percent (wt%) of abamectin (abamectin);

10 to 70 wt% of a non-polar solvent having a polar (P) value of the Hansen solubility parameter of 0 to 3,

0.5 to 80 wt% of a polar solvent of formula I:

wherein R is₁Is a C1 to C15 alkyl group; r2 is H or C1 to C8 alkyl; r₃Is a C1 to C15 alkylene group; and R is₄Is C1 to C15 alkyl, wherein the R₁、R₂、R₄Alkyl and R₃The sum of the carbons in the alkylene is 8 to 30; and

2.5 to 20 wt% of isocyanate, wherein each wt% is based on the total weight of the organic/oil mixture and the sum of the wt% of the avermectin, the non-polar solvent, the polar solvent and the isocyanate totals 100 wt%.

2. The organic mixture of claim 1, wherein the non-polar solvent is selected from the group consisting of aromatic petroleum derivatives, vegetable oils, hydrocarbons, esters, amides, and combinations thereof.

3. The organic mixture of claim 1, wherein the non-polar solvent is Solvesso^TM150#。

4. The organic mixture of any one of claims 1 to 3, wherein R₁Is a C1 to C8 alkyl group; r₃Is a C1 to C8 alkylene group; and R is₄Is a C1 to C8 alkyl group.

5. The organic mixture of any one of claims 1 to 4, wherein R is₁、R₂、R₄Alkyl and R₃The sum of the carbons in the alkylene group is 10 to 25.

6. The organic mixture of any of claims 1-5, wherein the polar solvent is 2,2, 4-trimethyl-1, 3-pentanediol monoisobutyrate.

7. The organic mixture of any of claims 1-6, wherein the isocyanate is selected from the group consisting of: methylene diphenyl diisocyanate (MDI), polymeric MDI (pdmi), Hexamethylene Diisocyanate (HDI), Toluene Diisocyanate (TDI), 1, 5-Naphthalene Diisocyanate (NDI), methylene dicyclohexyl isocyanate (HMDI), isophorone diisocyanate (IPDI), and combinations thereof.

8. An emulsion, comprising:

an organic/oil mixture comprising:

0.1 to 10 weight percent (wt%) of abamectin;

10 to 30 weight percent of a non-polar solvent;

0.5 to 30 wt% of a polar solvent of formula I:

wherein R is₁Is a C1 to C15 alkyl group; r2 is H or C1 to C8 alkyl; r₃Is a C1 to C15 alkylene group; and R is₄Is C1 to C15 alkyl, wherein the R₁、R₂、R₄Alkyl and R₃The sum of the carbons in the alkylene is 8 to 30; and

2.5 to 10 weight percent isocyanate; and

an aqueous mixture comprising:

0.5 to 20 wt% of a surfactant;

0.5 to 20 wt% of a dispersant;

0.01 to 2 weight percent of a thickener; and

40 to 55 wt% water, wherein each wt% is based on the total weight of the emulsion and the sum of the wt% of the organic/oil mixture and the aqueous mixture totals 100 wt%.

9. The emulsion of claim 8, wherein the non-polar solvent is selected from the group consisting of aromatic petroleum derivatives, vegetable oils, hydrocarbons, esters, amides, and combinations thereof.

10. The emulsion of claim 9, wherein the non-polar solvent is Solvesso^TM150#。

11. The emulsion of any one of claims 8 to 10, wherein R₁Is a C1 to C8 alkyl group; r₃Is a C1 to C8 alkylene group; and R is₄Is a C1 to C8 alkyl group.

12. The emulsion of any one of claims 8 to 11, wherein R is₁、R₂、R₄Alkyl and R₃The sum of the carbons in the alkylene group is 10 to 25.

13. The emulsion of any one of claims 8 to 12, wherein the polar solvent is 2,2, 4-trimethyl-1, 3-pentanediol monoisobutyrate.

14. The emulsion of any one of claims 8 to 13, wherein the isocyanate is selected from the group consisting of: methylene diphenyl diisocyanate (MDI), polymeric MDI, Hexamethylene Diisocyanate (HDI), Toluene Diisocyanate (TDI), 1, 5-Naphthalene Diisocyanate (NDI), methylene dicyclohexyl isocyanate (HMDI), or isophorone diisocyanate (IPDI), and combinations thereof.

15. The emulsion of any one of claims 8 to 14, wherein the surfactant is a branched alcohol alkoxylate.

16. The emulsion of any one of claims 8 to 15, wherein the dispersant is an acrylate-based dispersant polymer.

17. The emulsion of any one of claims 8 to 16, wherein the thickener is selected from the group consisting of natural polysaccharides, inorganic silicates, synthetic polymers, clays, or combinations thereof.

18. A microcapsule, comprising:

a coating formed from the reaction of an amine with an isocyanate in the emulsion of any one of claims 8 to 17; and

a liquid mixture contained within the coating forming the microcapsules, wherein the liquid mixture comprises abamectin, a non-polar solvent, a surfactant, a dispersant, a thickener, and water.

19. The microcapsule of claim 18, wherein the microcapsule is suspended in the aqueous mixture of claim 8.

Technical Field

The present disclosure relates to microencapsulation, and more particularly to microencapsulation of insecticides.

Background

Abamectin (abamectin) is widely used to control pests and mites in a variety of crops, fruits, vegetables and ornamental crops. However, abamectin has undesirable properties: first, it has high photosensitivity and is easily oxidized; second, it is toxic to humans and animals.

Attempts to solve the problems of photosensitivity and oxidation have taken different approaches. For example, avermectins are sold as Emulsion Concentrates (ECs) (e.g., at a concentration of 18g/L) that include antioxidants and/or uv screeners that help minimize photodegradation of the avermectins. Alternatively, the problem of photosensitivity of avermectins has been solved by microencapsulating avermectins using an emulsion process. The emulsification process of microencapsulation starts with the emulsification of an oil phase containing abamectin and hydrophobic solvent(s) in an aqueous phase containing surfactant(s) and dispersant(s). The microcapsules are then formed by polymerization of the monomer around the oil droplets in the emulsion.

However, the key to the first step of microencapsulation involves the preparation of the active solution with a solvent that has good compatibility and solubility with the suspension system in order to achieve the target active loading level. The suspension system also requires good hydrophobicity to facilitate the formation of microcapsules. However, the solubility of abamectin in typical hydrophobic aromatic agricultural solvents is very low. For example, it is difficult to achieve a loading level of even 1 wt% avermectin in the microcapsule.

Another problem that causes difficulties in microencapsulating avermectins is the chemistry used in the microencapsulation process. A typical microencapsulation process uses an interfacial polymerization process based on polyurea/polyurethane chemistry. This chemistry uses isocyanate monomers to create the microcapsule walls. However, abamectin has hydroxyl groups (one secondary and two tertiary) as seen in formula I below. These hydroxyl groups can react with isocyanate monomers, resulting in degradation of the avermectin during microcapsule formation.

Thus, there is a need in the art for improved microencapsulation of avermectins.

Disclosure of Invention

The present disclosure provides improvements in the microencapsulation of avermectins. The present disclosure provides, among other things, an active solution having a solvent with good abamectin solubility, achieving a target abamectin loading level (a level of 3 to 5 wt%), and having good hydrophobicity so as to facilitate capsule formation while minimizing abamectin degradation during the capsule formation process. In particular, it has been surprisingly found that the use of a specific polar solvent in combination with a non-polar solvent, referred to herein as an organic/oil mixture (discussed herein), results in microcapsules containing a weight percentage of avermectin comparable to the weight percentage of avermectin in the organic/oil mixture used to form the microcapsules. In other words, the weight percentage of avermectin in the microcapsules is surprisingly close to the weight percentage of avermectin in the organic/oil mixture used to form the microcapsules, which indicates that avermectin is surprisingly well protected during the encapsulation reaction.

As mentioned above, embodiments of the present disclosure include organic/oil mixtures for forming emulsions for forming the microcapsules of the present disclosure. The organic/oil mixture comprises 0.1 to 20 weight percent (wt%) abamectin; 10 to 70 wt% of a non-polar solvent having a Hansen solubility parameter (Hansen solubility parameter) with a polarity (P) value of 0 to 3; 0.5 to 80 wt% of a polar solvent of formula I:

wherein R is₁Is a C1 to C15 alkyl group; r2 is H or C1 to C8 alkyl; r₃Is a C1 to C15 alkylene group; and R is₄Is C1 to C15 alkyl, wherein R₁、R₂、R₄Alkyl and R₃The sum of the carbons in the alkylene is 8 to 30; and 2.5 to 20 wt% of isocyanate, wherein each wt% is based on the total weight of the organic/oil mixture and the sum of the wt% of avermectin, non-polar solvent, polar solvent and isocyanate totals 100 wt%.

The organic/oil mixture is used in an emulsion, wherein the emulsion comprises the organic/oil mixture and an aqueous mixture. The organic/oil mixture of the emulsion comprises 0.1 to 10 weight percent (wt%) of abamectin; 10 to 30 weight percent of a non-polar solvent; 0.5 to 30 wt% of a polar solvent of formula I:

wherein R is₁Is a C1 to C15 alkyl group; r2 is H or C1 to C8 alkyl; r₃Is a C1 to C15 alkylene group; and R is₄Is C1 to C15 alkyl, wherein R₁、R₂、R₄Alkyl and R₃The sum of the carbons in the alkylene is 8 to 30; and 2.5 to 10 weight percent isocyanate. The aqueous mixture comprises 0.5 to 20 wt% of a surfactant; 0.5 to 20 wt% of a dispersant; 0.01 to 2 weight percent of a thickener; and 40 to 55 wt% water, wherein each wt% of the emulsion is based on the total weight of the emulsion and the sum of the wt% of the organic/oil mixture and the aqueous mixture totals 100 wt%.

Preferably, R₁Is a C1 to C8 alkyl group; r₃Is a C1 to C8 alkylene group; and R is₄Is a C1 to C8 alkyl group. Preferably, R₁、R₂、R₄Alkyl and R₃The sum of the carbons in the alkylene group is 10 to 25. Most preferably, the polar solvent is 2,2, 4-trimethyl-1, 3-pentanediol monoisobutyrate.

As described herein, the polar (P) value of the hansen solubility parameter of a non-polar solvent is from 0 to 3, wherein such non-polar solvent is selected from the group consisting of aromatic petroleum derivatives, vegetable oils, hydrocarbons, esters, amides, and combinations thereof. In a preferred embodiment, the non-polar solvent is Solvesso^TM150# (ExxonMobil Co., Ltd.), which is an aromatic petroleum derivative.

For the various embodiments, the isocyanate is selected from the group consisting of: methylene diphenyl diisocyanate (MDI), polymeric MDI, Hexamethylene Diisocyanate (HDI), Toluene Diisocyanate (TDI), 1, 5-Naphthalene Diisocyanate (NDI), methylene dicyclohexyl isocyanate (HMDI), isophorone diisocyanate (IPDI), and combinations thereof.

For aqueous mixtures, the surfactant is a branched alcohol alkoxylate. The dispersant is an acrylate-based dispersant polymer. The thickener is selected from the group consisting of natural polysaccharides, inorganic silicates, synthetic polymers, clays, or combinations thereof.

The present disclosure also includes microcapsules comprising a coating formed by reacting an amine with an isocyanate in an emulsion as provided herein, and a liquid mixture contained within the coating forming the microcapsules, wherein the liquid mixture comprises abamectin, a non-polar solvent, a surfactant, a dispersant, a thickener, and water. The microcapsules are suspended in an aqueous mixture.

Detailed Description

The present disclosure provides improvements in the microencapsulation of avermectins. The present disclosure provides, among other things, an active solution having a solvent with good abamectin solubility, achieving a target abamectin loading level (a level of 3 to 5 wt%), and having good hydrophobicity so as to facilitate capsule formation while minimizing abamectin degradation during the capsule formation process. In particular, it has been surprisingly found that the use of a specific polar solvent in combination with a non-polar solvent, referred to herein as an organic/oil mixture (discussed herein), allows the weight percentage of avermectins contained by the microcapsules to be comparable to the weight percentage of avermectins in the organic/oil mixture used to form the microcapsules. In other words, the weight percentage of avermectin in the microcapsules is surprisingly close to the weight percentage of avermectin in the organic/oil mixture used to form the microcapsules, which indicates that avermectin is surprisingly well protected during the encapsulation reaction.

As provided herein, the organic/oil mixture is used with an aqueous mixture to form an emulsion. An amine is added to the emulsion, wherein the amine reacts with the isocyanate present in the organic/oil mixture to form a coating around the organic/oil mixture by an interfacial polymerization process, thereby forming the microcapsules of the present disclosure. The liquid mixture contained within the coating forming the microcapsules comprises abamectin.

Organic/oil mixtures

Embodiments of the present disclosure include an organic/oil mixture for forming an emulsion that is subsequently used to form the microcapsules of the present disclosure. The organic/oil mixture comprises 0.1 to 20 weight percent (wt%) abamectin; 10 to 70 weight percent of a non-polar solvent having a hansen solubility parameter with a polarity (P) value of 0 to 3; 0.5 to 80 wt% of a polar solvent of formula I:

wherein R is₁Is a C1 to C15 alkyl group; r2 is H or C1 to C8 alkyl; r₃Is a C1 to C15 alkylene group; and R is₄Is C1 to C15 alkyl, wherein R₁、R₂、R₄Alkyl and R₃The sum of the carbons in the alkylene is 8 to 30; and 2.5 to 20 wt% of isocyanate, wherein each wt% is based on the total weight of the organic/oil mixture and the sum of the wt% of avermectin, non-polar solvent, polar solvent and isocyanate totals 100 wt%.

The organic/oil mixture comprises 0.1 to 20 wt% of abamectin, wherein the wt% is based on the total weight of the organic/oil mixture. Preferably, the organic/oil mixture comprises 0.1 to 10 wt% of abamectin. In a preferred embodiment, the organic/oil mixture comprises 3 to 5 wt% of abamectin. Abamectin (CAS registry No. 71751-41-2) is a mixture containing more than 80 wt% abamectin B1a (CAS registry No. 65195-55-3) and abamectin B1B (CAS registry No. 65195-56-4) constituting the remainder, i.e. to 100 wt%. Avermectin is a pesticide derived from the soil bacterium Streptomyces avermitilis. Avermectin is commercially available from Hebei Wei Yongbio Chemicals, Inc. (Hebei Veyong Bio-Chemical Co., Ltd.).

Although the present disclosure uses avermectins, it is understood that other biologically active compounds having a hydroxyl group similar to avermectins, in addition to avermectins, may be used with the organic/oil mixture in forming the emulsions and microcapsules of the present disclosure. Such biologically active compounds may include, but are not limited to, macrolides including avermectins (avermectins) (ivermectins, avermectins, and dorametins) and milbemycins (milbemycins) (milbemycins oxime and moxidectin), and the like.

The organic/oil mixture further comprises 10 to 70 weight percent of a non-polar solvent having a hansen solubility parameter with a polarity (P) value of 0 to 3, wherein weight percent is based on the total weight of the solvent organic/oil mixture. Preferably, the organic/oil mixture comprises 20 to 60 wt% of the non-polar solvent. Generally, useful non-polar solvents for the present disclosure include, but are not limited to, agriculturally acceptable hydrophobic solvents having low water solubility (e.g., less than 0.1 weight percent) at room temperature (e.g., 23 ℃) and a polar (P) value of 0 to 3 for the hansen solubility parameter. As used herein, the hansen solubility parameter website is used (bhttps:// www.hansen-solubility.com/buy-HSPiP-software.php) The software available above calculates the polarity (P) value of the hansen solubility parameter. The polarity (P) value of the hansen solubility parameter can also be calculated based on: hansen solubility parameters: user manual second edition (Hansen Solubility Parameters: A user's hand)book, second edition.). Poladradon, Flo, CRC Press, ISBN 978-0-8493-. The polarity values for the hansen solubility parameters provided herein are measured at room temperature (23 ℃).

Such non-polar solvents are selected from the group consisting of aromatic petroleum derivatives, vegetable oils, hydrocarbons, esters, amides, and combinations thereof. Examples of aromatic petroleum derivatives include those available under the trade name Solvesso^TM100、Solvesso^TM150、Solvesso^TM200、Solvesso^TM150ND、Solvesso^TM200ND、Aromatic^TM150、Aromatic^TM200、Hydrosol^TMA200、Hydrosol^TMA 230/270、Caromax^TM20、Caromax^TM28、Aromat^TMK 150、Aromat^TMK200 and Shellsol^TMA150 and the like are those commercially available from Exxon Mobil corporation or British Petroleum. In a preferred embodiment, the non-polar solvent is Solvesso^TM150# (exxon mobil corporation), which is an aromatic petroleum derivative. Examples of vegetable oils include soybean oil, rapeseed oil, palm oil, and corn oil, among others. Examples of hydrocarbons include pentane, hexane, and the like, straight-chain alkanes, isoalkanes, and cycloalkanes. Examples of esters include, but are not limited to, terpene esters, benzyl acetate, benzyl benzoate. Examples of amides include N, N-dialkylamides, commercially available as Hallcomide M810 from The PC Hall Co., and Gengen 4166 from Clariant Corporation. Combinations of any of the above non-polar solvents may also be used.

The organic/oil mixture further comprises 0.5 to 80 wt% of a polar solvent of formula I, wherein wt% is based on the total weight of the organic/oil mixture. Preferably, the organic/oil mixture comprises 10 to 70 wt% of the polar solvent. In contrast to non-polar solvents, polar solvents of the present disclosure have a polarity (P) value of the hansen solubility parameter of greater than 3 to 10, as measured/calculated according to the methods discussed herein for non-polar solvents. As noted above, the polar solvent is shown in formula I:

wherein R is₁Is a C1 to C15 alkyl group; r2 is H or C1 to C8 alkyl; r₃Is a C1 to C15 alkylene group; and R is₄Is C1 to C15 alkyl, wherein R₁、R₂、R₄Alkyl and R₃The sum of the carbons in the alkylene is 8 to 30; and 2.5 to 20 wt% of isocyanate, wherein each wt% is based on the total weight of the organic/oil mixture and the sum of the wt% of avermectin, non-polar solvent, polar solvent and isocyanate totals 100 wt%. Preferably, R₁Is a C1 to C8 alkyl group; r₄Is a C1 to C8 alkyl group; and R is₃Is a C1 to C8 alkylene. Preferably, R₁、R₂、R₃And R₄The sum of the carbons in the alkyl group is 10 to 25. Most preferably, the polar solvent is 2,2, 4-trimethyl-1, 3-pentanediol monoisobutyrate (IBT).

As provided herein, the use of a polar solvent helps to protect the avermectin from decomposition during microcapsule formation. In particular, the hydroxyl groups in the polar solvent help to reduce the degradation of abamectin that may be caused by the reaction between isocyanate groups and the hydroxyl groups in abamectin. The polar solvent helps to form stable emulsions and microcapsule suspensions even under cold and hot aging tests and ultraviolet stability tests, as seen in the examples section below.

Examples of suitable polar solvents of the present disclosure also include, but are not limited to, solvents having similar solubility parameters as the ester alcohols described above. Examples of such polar solvents include butyl formate (CAS 592-84-7), diethylene glycol hexyl ether (CAS 112-59-4), dipropylene glycol mono-n-butyl ether (CAS 29911-28-2), ethylene glycol monoethyl ether acrylate (CAS 106-74-1), meclofenoxate (CAS 51-68-3), methanol cluster (CAS 67-56-1), methyl acrylate (CAS 96-33-3), propylene glycol monomethyl ether acetate (CAS 108-65-6), propylene glycol monopropyl ether (CAS 1569-01-3), 2, 4-trimethyl-1, 3-pentanediol monoisobutyrate (CAS 25265-77-4), vinyl crotonate (CAS 14861-06-4), vinyl formate (CAS 692-45-5), 2,2,3,4,4, 4-hexafluorobutan-1-ol (CAS 382-31-0), 1,1, 1-trifluoro-2-methylpropan-2-ol (CAS 507-52-8), 1-pentanol, 2,3,3,4,4,5, 5-octafluoro (CAS 355-80-6), ethyl 2-methyl-3-hydroxy-4, 4, 4-trifluorobutyrate (CAS91600-33-8), and propylene glycol 2-tert-butyl ether (CAS 94023-15-1).

The organic/oil mixture further comprises 2.5 to 30 weight percent of an isocyanate, wherein weight percent is based on the total weight of the organic/oil mixture. Preferably, the organic/oil mixture comprises 5 to 20 wt% of isocyanate. The isocyanates of the present disclosure may include, but are not limited to, methylene diphenyl diisocyanate (MDI), polymeric MDI (pdmi), Hexamethylene Diisocyanate (HDI), Toluene Diisocyanate (TDI), 1, 5-Naphthalene Diisocyanate (NDI), methylene dicyclohexyl isocyanate (HMDI), isophorone diisocyanate (IPDI), and combinations thereof. Suitable isocyanates may also include other aromatic and/or aliphatic polyfunctional isocyanates. Aromatic isocyanates include those containing phenyl, tolyl, xylyl, naphthyl, or diphenyl moieties or combinations thereof, such as trimethylolpropane adduct of xylylene diisocyanate, trimethylolpropane adduct of toluene diisocyanate, 4' -diphenyldimethane diisocyanate (MOI), Xylylene Diisocyanate (XDI), 4' -diphenyldimethylmethane diisocyanate, dialkyldiphenylmethane diisocyanates and tetraalkyldiphenylmethane diisocyanates, 4' -dibenzyl diisocyanate, 1, 3-phenylene diisocyanate, 1, 4-phenylene diisocyanate, and combinations thereof. Suitable aliphatic polyfunctional isocyanates include the trimer of hexamethylene diisocyanate, the trimer of isophorone diisocyanate, the biuret of hexamethylene diisocyanate, the hydrogenated polymeric methylene diphenyl diisocyanate, the hydrogenated MDI, the tetramethylxylene diisocyanate (TMXDI), 1-methyl-2, 4-diisocyanatocyclohexane, 1, 6-diisocyanate-2, 2, 4-trimethylhexane, 1-isocyanatomethyl-3-isocyanato-1, 5, 5-trimethylcyclohexane, tetramethoxybutane 1, 4-diisocyanate, butane 1, 4-diisocyanate, hexane 1, 6-diisocyanate, dicyclohexylmethane diisocyanate, the diisocyanate, Cyclohexane 1, 4-diisocyanates and combinations thereof

Emulsion and method of making

The organic/oil mixture is used in an emulsion, wherein the emulsion comprises the organic/oil mixture and an aqueous mixture. As used herein, the aqueous mixture includes water, surfactant, thickener, and dispersant, wherein an amine is added after the emulsion is formed to crosslink the isocyanate and form the walls of the disclosed microcapsules.

The organic/oil mixture of the emulsion comprises 0.1 to 10 weight percent (wt%) of abamectin; 10 to 30 weight percent of a non-polar solvent; 0.5 to 30 wt% of a polar solvent of formula I:

wherein R is₁Is a C1 to C15 alkyl group; r2 is H or C1 to C8 alkyl; r₃Is a C1 to C15 alkylene group; and R is₄Is C1 to C15 alkyl, wherein R₁、R₂、R₄Alkyl and R₃The sum of the carbons in the alkylene is 8 to 30; and 2.5 to 10 weight percent isocyanate. The aqueous mixture comprises 0.5 to 20 wt% of a surfactant; 0.5 to 20 wt% of a dispersant; 0.01 to 2 weight percent of a thickener; and 40 to 55 wt% water, wherein each wt% of the components of the emulsion is by total weight of the emulsion, and the sum of the wt% of the organic/oil mixture and the aqueous mixture totals 100 wt%.

Examples of avermectins, non-polar solvents, polar solvents and isocyanates are described above. Preferably, the organic/oil mixture of the emulsion comprises 0.1 to 10 weight percent (wt%) of abamectin; 10 to 30 weight percent of a non-polar solvent; 0.5 to 30 wt% of a polar solvent of formula I; and 2.5 to 10 weight percent isocyanate, as described above. More preferably, the organic/oil mixture of the emulsion comprises 3 to 5% by weight of abamectin; 10 to 22 wt% of a non-polar solvent; 25 to 27% by weight of a polar solvent of the formula I and 4 to 8% by weight of an isocyanate.

The aqueous mixture includes 0.5 to 20 wt% of a surfactant. Preferably, the aqueous mixture comprises 1 to 10 wt% surfactant, and more preferably, the aqueous mixture comprises 2 to 8 wt% surfactant. Examples of surfactants include, but are not limited to, branched alcohol alkoxylates, ethylene oxide/propylene oxide (EO/PO) copolymers, dialkyl sulfosuccinates, phosphate-based surfactants, alkyl diphenyl oxide disulfonate surfactants, and anionic sulfonate or sulfate surfactants, and any combination thereof. Preferably, the surfactant is a branched alcohol alkoxylate. As provided herein, branched alcohol alkoxylates may include primary and/or secondary branched alcohol alkoxylates.

Examples of primary branched alcohol ethoxylates include, for example, those available under the trade name ECOSURF^TME.g. ECOSURF^TMEH-9、ECOSURF^TMEH-9 and combinations thereof. Secondary branched alcohol ethoxylates include, for example, those available under the trade name Tergitol^TM15-S-9、Tergitol^TM15-S-12 and combinations thereof. Examples of EO-PO copolymers include those available under the trade name Tergitol^TML-61 and Tergitol^TML-64、Dowfax^TMD-800、Dowfax^TMD-850 and combinations thereof. Examples of dialkyl sulfosuccinates include, for example, those available under the tradename Triton^TMGR-7M、Triton^TMGR-5M and combinations thereof are commercially available. Examples of phosphate esters include those available under the trade name Triton^TMH-55、Triton^TMH-66、Triton^TMQS-44 and Triton^TMXQS-20 and combinations thereof. The alkyl polyglycosides include, for example, those available under the trade name Triton^TMCG-50、Triton^TMCG-110、Triton^TMCG-600、Triton^TMCG-650 and combinations thereof. Alkyl diphenyl ether disulfonates include, for example, those available under the trade name Dowfax^TM2A1、Dowfax^TM8390, etc., and mixtures thereof. Sulfonate or sulfate surfactants include, for example, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium dodecylnaphthalenesulfonate, available under the trade name Triton^TMQS-15、Triton^TMXN-45 and combinations thereof.

The aqueous mixture includes 0.5 to 20 wt% of a dispersant. Preferably, the aqueous mixture comprises 1 to 10 wt% of the dispersant, and more preferably, the aqueous mixture comprises 2 to 8 wt% of the dispersant. Preferably, the dispersant is a baseA dispersant polymer in an acrylate. Examples of dispersants include, but are not limited to, copolymers of maleic acid or maleic anhydride with an olefin (e.g., isobutylene or diisobutylene), copolymers of polyacrylic acid and methacrylic acid grafted by polyoxyethylene, copolymers of acrylic acid esters and acrylic or methacrylic acid, and combinations thereof. Specific examples include, but are not limited to, commercially available products such as GeroponT/36, Powerblox^TMD-305、Powerblox^TMD-205、Oratan^TM731A and combinations thereof.

The aqueous mixture comprises 0.01 to 2% by weight of a thickener. Preferably, the aqueous mixture comprises 0.05 to 1 wt% of a thickener. The thickener is selected from the group consisting of natural polysaccharides, inorganic silicates, synthetic polymers, clays, or combinations thereof. Examples of natural polysaccharides include, but are not limited to, xanthan gum, carrageenan, locust bean gum. Examples of inorganic silicates include, but are not limited to, silica, magnesium aluminum silicate, and compounds of the smectite group of compounds. Examples of synthetic polymers include, but are not limited to, polyurethanes. Examples of clays include those known in the art.

The aqueous mixture also includes 40 to 55 weight percent water. The water may be deionized water or ultrafiltered water, as is known in the art.

Microcapsules

As provided herein, the microcapsules of the present disclosure include a coating formed from the reaction of an amine with an isocyanate present in the organic/oil mixture of the emulsion. The microcapsules also include a liquid mixture contained within the coating forming the microcapsules. The liquid mixture inside the microcapsule comprises abamectin, a non-polar solvent, a surfactant, a dispersant, a thickener and water. The microcapsules are suspended in an aqueous mixture.

Amines that may be used to form the microcapsules of the present disclosure include, but are not limited to, ethylamine, ethylenediamine, triethylenetetramine, 1, 6-hexamethylenediamine, bis-hexamethylenetriamine, dimethylamine, tetraethylenepentamine, trimethylamine, diethylamine, diisopropylamine, dimethylaminopropylamine, triisopropylamine, polyamine, or combinations thereof. Other well-known water-soluble amines may also be used to form the microcapsules of the present disclosure. The monomer which can react with the isocyanate monomer to produce the microcapsule wall can also be an active hydrogen containing compound such as a water soluble diol or polyol, for example ethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol.

Microcapsule preparation is an interfacial polymerization process using polyurea/polyurethane chemistry in which isocyanate monomers assist in forming the microcapsule wall. However, abamectin includes hydroxyl functions that may react during the encapsulation process, thus risking active degradation. However, the present disclosure has surprisingly found that the use of specific polar solvents in combination with non-polar solvents, as provided herein, results in microcapsules containing a weight percentage of avermectin comparable to the weight percentage of avermectin in the organic/oil mixture used to form the microcapsules. In other words, the weight percentage of abamectin in the microcapsules is surprisingly close to the weight percentage of abamectin in the organic/oil mixture used to form the microcapsules.

To form the microcapsules, the non-polar solvent, the polar solvent of the organic/oil mixture are mixed at room temperature (23 ℃). The isocyanate is then added to the non-polar solvent/polar solvent mixture followed by the addition of the avermectin to form an organic/oil mixture. The organic/oil mixture is mixed with an overhead stirrer (e.g., at 200 to 300 revolutions per minute (rpm) for 5 to 10 minutes) to form a homogeneous mixture.

Likewise, the aqueous mixture is prepared by mixing surfactant(s), dispersant(s), thickener, and water (e.g., deionized water) at room temperature. For example, the aqueous mixture may be mixed with an overhead stirrer (e.g., at 200 to 300 revolutions per minute (rpm) for 5 to 10 minutes) to form a homogeneous mixture. The aqueous mixture and the organic/oil mixture are then mixed to form a two-phase mixture. The two-phase mixture was then mixed at room temperature by mixing with an overhead stirrer at a speed of about 1000 to 2000rpm for about 5 to 10 minutes to form an emulsion. Mixing speed and duration were continued until the particle size of the organic/oil mixture in the emulsion was less than 10 microns, with size confirmed using light microscopy.

The amine is then added to the emulsion at room temperature to form the microcapsules. The amine may be added in an amount of 0.1 to 5 moles per mole of isocyanate in the organic/oil mixture. The amine may be added to the emulsion as an amine solution having 5 to 20 weight percent amine in water (e.g., deionized water) based on the total weight of the amine solution. In particular, the amine solution can be added dropwise to the emulsion at room temperature with stirring to maintain good mixing. After the amine addition was complete, the resulting microcapsule suspension was stirred at 200-500rpm for an additional time interval (e.g., one minute).

Examples of the invention

Some embodiments of the present disclosure will now be described in detail in the following examples.

Raw materials:

microcapsule preparation

Microcapsule preparation is an interfacial polymerization process using polyurea/polyurethane chemistry in which isocyanate monomers assist in forming the microcapsule wall. However, abamectin includes hydroxyl functions that may react during the encapsulation process, thus risking active degradation. However, the present disclosure has surprisingly found that the use of specific polar solvents in combination with non-polar solvents, as provided herein, results in microcapsules containing a weight percentage of avermectin comparable to the weight percentage of avermectin in the organic/oil mixture used to form the microcapsules. In other words, the weight percentage of abamectin in the microcapsules is surprisingly close to the weight percentage of abamectin in the organic/oil mixture used to form the microcapsules. For example, as seen below, the weight percentage of abamectin in the microcapsules of example 2 was the same as the weight percentage of abamectin in the organic/oil mixture when the microcapsules were formed, indicating that abamectin was surprisingly well protected during the encapsulation reaction.

The non-polar solvent, the polar solvent (when used), followed by the isocyanate, were mixed at room temperature (23 ℃) in the amounts listed in table 1 (examples) and table 2 (comparative examples) to form a solvent mixture. Abamectin was added to the solvent mixture at room temperature in accordance with the amounts listed in tables 1 and 2 to form an organic/oil mixture. The organic/oil mixture was mixed with an IKA overhead stirrer at 200 to 300 revolutions per minute (rpm) to form a homogeneous mixture.

An aqueous mixture was prepared by mixing surfactant(s), dispersant(s), thickener, and Deionized (DI) water as shown in tables 1 and 2 at room temperature. The aqueous mixture was added to the organic/oil mixture to give a two-phase mixture. The two-phase mixture was emulsified at room temperature by mixing with an IKA overhead stirrer at a speed of about 1000rpm to form an emulsion. The emulsification process was continued until the particle size in the emulsion was less than 10 microns (size confirmed using light microscopy).

A 10 weight percent (wt%) aqueous solution of Ethylenediamine (EDA) was prepared to form an amine solution. The amine solution was added dropwise to the emulsion at room temperature in the amounts shown in tables 1 and 2 while stirring at a reduced speed to maintain good mixing. After the amine addition was complete, the resulting microcapsule suspension was stirred at 200-500rpm for an additional minute.

For the examples (table 1) and comparative examples (table 2), the content of each ingredient shown in tables 1 and 2 is given in weight percent based on the total weight of the microcapsule suspension, unless otherwise specified.

TABLE 1-Examples 1 to 5

The capsules contained about 0.4% butylated hydroxytoluene (BHT, a UV stabilizer).

TABLE 2Comparative examples A and B

The formation of microcapsules was confirmed using optical and fluorescence microscopy. The microcapsules were destroyed using pressure and confirmed using both optical and fluorescence microscopy that the contents were hydrophobic due to the formation of small droplets of the contents from the microcapsules in the aqueous phase. The observation confirmed that abamectin was well encapsulated in microcapsules.

Test program

Examples the following test procedures were used.

a) Thermal aging test

From a sample of the microcapsule suspension as prepared in the microcapsule preparation section above, the percentage of avermectin is measured according to the method discussed in section c) below of the present disclosure. From the same sample of microcapsule suspension as prepared in the microcapsule preparation section above, 100 grams of microcapsule suspension was placed in a 1 liter beaker and the beaker was covered to prevent evaporation. The beaker with the lid was placed in an oven set at 54 ℃ and left at 54 ℃ for 2 weeks. After 2 weeks, the beaker was removed and the microcapsule suspension was allowed to return to room temperature to form a heat aged sample of the microcapsule suspension. The percentage of avermectin in the heat aged sample of the microcapsule suspension was measured according to the method discussed in section c) below. Table 5 provides the results of these tests.

b) UV aging test

From a sample of the microcapsule suspension as prepared in the microcapsule preparation section above, the percentage of avermectin is measured according to the method discussed in section c) below of the present disclosure. From the same sample of microcapsule suspension as prepared in the microcapsule preparation section above, 10 grams were placed into a glass vial and the sample was exposed to energy of 100 μ J/cm using UVP, LLC CL-1000 ultraviolet crosslinker³For 20 hours, to form a UV aged sample of the microcapsule suspension. The percentage of avermectin in the UV aged sample of the microcapsule suspension was measured according to the method discussed in section c) below. Table 6 provides the results of these tests.

Also, from a sample of the emulsion as prepared in the microcapsule preparation section above, in accordance with the present disclosureThe method as discussed in section c) above, the percentage of abamectin is measured. From the same sample of emulsion as prepared in the microcapsule preparation section above, 10 grams were placed into a glass vial and the sample was exposed to energy of 100 μ J/cm using UVP, LLC CL-1000 ultraviolet crosslinker³For 20 hours, to form a UV aged sample of the emulsion. The percentage of avermectin in the UV aged sample of the emulsion was measured according to the method discussed in section c) below. Table 6 provides the results of these tests.

c) Measurement of Avermectin content and encapsulation efficiency

The content of avermectin in the microcapsules and the encapsulation efficiency of avermectin were determined as follows.

A 5ml sample of the microcapsule suspension as prepared in the microcapsule preparation section above was centrifuged at 5800rpm for 10 minutes to separate the microcapsules from the aqueous phase. At room temperature, 0.1 gram of the isolated microcapsules was suspended in 10ml of analytical grade methanol to form a test sample of microcapsules. The test sample of microcapsules was sonicated using an Ultrasonic cleaner (SK3210LHC, Shanghai Kudos Ultrasonic instrument ltd co., ltd) for 10 minutes at room temperature to form a sonicated microcapsule sample.

The amount of abamectin in the sonicated microcapsule samples and the emulsion samples as prepared in the microcapsule preparation section above were measured using reversed phase high pressure liquid chromatography with diode array detector (Agilent 1200HPLC) and Agilent Zorbax SDB-C18, 4.6 x 150mm, 5 μm column according to the parameters shown in table 3. The amount of avermectin in the sonicated microcapsule sample and the emulsion sample as prepared in the microcapsule preparation section above were compared to determine the encapsulation efficiency of avermectin.

TABLE 3

Results

Solubility of avermectin in solvent and in microcapsules

Level of loading in suspension

As seen above, the general method of forming a microcapsule suspension involves forming an emulsion with an organic/oil mixture and an aqueous mixture, and then forming capsules around the droplets of the organic/oil mixture by polymerization of the monomers. The avermectin loading levels achieved in the present disclosure are attributed to the solvent mixture, wherein the solvent according to the present disclosure has excellent compatibility with avermectin, thereby achieving the target avermectin loading levels while also providing the necessary hydrophobicity relative to the aqueous mixture to facilitate microcapsule formation.

Table 4 below provides the solubility values (in weight percent relative to the total weight of the composition) of abamectin in various solvents at room temperature.

TABLE 4-Solubility of Avermectin in solvent

As shown in table 4, the solubility of abamectin in hydrophobic solvents is very low (comparative examples C to G), falling to values below 1%. Among these solvents are rosin vegetable oil ND-60 and aromatic solvent Solvesso^TM150#, which are commonly used agricultural solvents, the use of such solvents may result in active loading levels that may be below 1%, as seen in comparative examples a-C.

In contrast, in UCAR^TMAbamectin solubility in Filmer IBT was up to 14.0% (example 6) and was found to be compatible with the aromatic solvent Solvesso^TM150# the solubility was greater than 10%, as seen in table 4. Thus, the combination of solvents and the weight percentages selected provided in the present disclosure can significantly improve the solubility of avermectins, and thus potentially enable high avermectins loading levels (e.g., 3% to 5% or possibly greater) in capsule suspension formulations (e.g., examples 1-5).

Stability of avermectins in microcapsules during storage at different temperatures

As discussed above, the stability of abamectin in microcapsules during storage was evaluated by means of a thermal ageing test. As shown in table 5, heat aging the avermectin containing microcapsules at 54 ℃ for 2 weeks resulted in almost no loss of avermectin. This result is similar to the aging test of the avermectin containing microcapsules at 0 ℃ for 1 week.

TABLE 5Weight percentage of avermectin in the microcapsules from the sample of example 2

Stability of avermectins exposed to UV light in microcapsules

As described herein, abamectin is highly sensitive to light, particularly UV light. One approach to solving this important problem is to encapsulate and/or include abamectin with a UV stabilizer. The results of the UV aging test discussed above are shown in table 6. As seen in table 6, samples of the emulsion (comparative example 4, 3.18% abamectin + 15.00% NMP + 81.82% Solvesso # 150) and the microcapsule suspension of example 4 as prepared in the microcapsule preparation section above were exposed to UV light for 20 hours, as discussed above. As shown in table 6, 16.25% of the avermectin was lost without the protection of the microcapsule wall (comparative example 4), while only about 2% to 3% of the avermectin was lost when contained in the microcapsules of the present disclosure (example 4) and in the example also including a UV stabilizer in the interior (example 5). This data indicates that the microcapsules contribute to significantly improving UV stability.

TABLE 6-Stability of activity against UV ageing

Comparative example 4 is an EC sample, 3.18% abamectin + 15.00% NMP + 81.82% Solvesso # 150.

Inventive example 5: the UV stabilizer BHT is inside the capsules.