A tetrameric acetaldehyde granule with both attractiveness and waterproofness and a preparation method thereof

Abstract

The application discloses a kind of tetrameric acetaldehyde granules and preparation method thereof, which have both attractivity and waterproofness.The tetrameric acetaldehyde is mixed with fillers, filler attractants and binders after adding water, and then granulated.The prepared granules are coated with a coating agent containing polyethylene glycol monomethacrylate or sodium lignosulfonate, and then sprayed, coated and dried to obtain the tetrameric acetaldehyde granules with both attractivity and waterproofness.The test results show that the tetrameric acetaldehyde granules have strong attractivity to golden apple snails, and the tetrameric acetaldehyde in the granules will not be quickly precipitated into water after being contacted with water, so that the tetrameric acetaldehyde can be used for long-term to kill golden apple snails, which is conducive to the efficient prevention and control of golden apple snails.

Description

Technical Field

[0001] This invention belongs to the field of pesticide technology. More specifically, it relates to a metaldehyde granule formulation that combines attractant and waterproof properties, and its preparation method. Background Technology

[0002] Golden apple snails are an invasive species with a large appetite, rapid reproduction rate, and high reproductive capacity, causing serious damage in rice-growing areas. While chemical agents such as metaldehyde can be used to control golden apple snails, the application of metaldehyde suspensions diluted in water requires sophisticated application techniques and is susceptible to environmental influences, leading to reduced efficacy and necessitating large-scale use, which results in waste and environmental pollution. Although using metaldehyde granules can reduce the amount of metaldehyde used and avoid large-scale water pollution, existing metaldehyde granules also have the following shortcomings in controlling golden apple snails: First, they lack sufficient attractant and palatability, making it difficult to entice snails to feed, resulting in low efficacy; second, they lack water resistance. The flour and other materials used to improve palatability easily disperse upon contact with water, and metaldehyde itself has a certain degree of water solubility. Even if the granules do not disintegrate in water, the metaldehyde will still dissolve, reducing efficacy and causing water pollution.

[0003] Adding an attractant to metaldehyde granules and coating them with a hydrophobic film could potentially address the shortcomings of existing metaldehyde granules. However, actual testing revealed that while coating the granules with a film improves their water resistance and provides a degree of slow-release effect, it also negatively impacts their attractant and control efficacy. This means that improving a specific aspect of metaldehyde granules' performance cannot be achieved simply by introducing a targeted ingredient that enhances that performance. This inherent uncertainty makes the development of metaldehyde granules that balance attractant and water resistance highly uncertain.

[0004] In summary, there is still a need to develop metaldehyde granules that combine attraction and water resistance to improve the control of golden apple snails while reducing the adverse environmental impact of metaldehyde. Summary of the Invention

[0005] This invention addresses the shortcomings of existing metaldehyde granules by providing a metaldehyde granule that combines attraction and water resistance.

[0006] The first objective of this invention is to provide a tetraacetaldehyde granule that combines attraction and water resistance.

[0007] A second objective of this invention is to provide a method for preparing the metaldehyde granules.

[0008] A third objective of this invention is to provide the application of the aforementioned metaldehyde granules in the preparation of products for the control of golden apple snails.

[0009] The above-mentioned objective of this invention is achieved through the following technical solution:

[0010] Through continuous screening and optimization, this invention has yielded a metaldehyde granular agent that combines attraction and water resistance. Using this metaldehyde granular agent can improve the control effect on golden apple snails while reducing the adverse environmental impact of metaldehyde. Therefore, this invention seeks protection for the metaldehyde granular agent and its preparation method.

[0011] This invention provides a method for preparing metaldehyde granules that combine attraction and water resistance, comprising the following steps:

[0012] S1. Mix 4-8 parts of metaldehyde, 30-50 parts of filler, 16-26 parts of filler inducer and 15-25 parts of binder with water to form granules;

[0013] S2. Dissolve 5-15 parts of coating material in water, then add 0.01-0.05 parts of coating inducer and mix well to prepare a coating agent. Use the coating agent to spray-coat the particles obtained in S1 and dry them to prepare the granules.

[0014] The filler is one or more of kaolin, diatomaceous earth, and diatomaceous earth filter aid.

[0015] The filler attractant consists of a matrix and an attractant, with a mass ratio of matrix to attractant of 22-28:1; the matrix is ​​one or more of wheat flour, rice flour, and corn flour; wheat flour, corn flour, etc. have similar properties and are commonly used substitutes for each other; the attractant is erythritol and / or thiamethoxam dimethyl-β-propionate.

[0016] The adhesive is one or more of dextrin, polyvinyl alcohol, carboxymethyl cellulose, sodium alginate, pregelatinized starch, and polyvinylpyrrolidone; wherein dextrin, carboxymethyl cellulose, sodium alginate, and pregelatinized starch belong to the same major category and are all natural polysaccharide polymers or their derivatives; when used as an adhesive, polyvinyl alcohol, carboxymethyl cellulose, polyvinylpyrrolidone, and pregelatinized starch are often interchangeable.

[0017] The coating material is sodium lignosulfonate and / or polyethylene glycol monomethacrylate.

[0018] The encapsulation attractant is erythritol and / or thiatin dimethyl-β-propionic acid.

[0019] Preferably, the preparation method includes the following steps:

[0020] S1. Mix 4-8 parts of metaldehyde, 35-45 parts of filler, 18-24 parts of filler attractant and 18-22 parts of binder with water to form granules;

[0021] S2. Dissolve 5-10 parts of coating material in water, then add 0.01-0.03 parts of coating inducer and mix well to prepare a coating agent. Use the coating agent to spray-coat the particles obtained in S1 and dry them to prepare the granules.

[0022] More preferably, the preparation method includes the following steps:

[0023] S1. Mix 5-7 parts of metaldehyde, 38-42 parts of filler, 20-22 parts of filler attractant and 18-22 parts of binder with water to form granules;

[0024] S2. Dissolve 8-10 parts of coating material in water, then add 0.01-0.02 parts of coating inducer and mix well to prepare a coating agent. Use the coating agent to spray-coat the particles obtained in S1 and dry them to prepare the granules.

[0025] More preferably, the preparation method includes the following steps:

[0026] S1. Mix 6 parts of metaldehyde, 40 parts of filler, 21 parts of filler attractant and 20 parts of binder with water to form granules;

[0027] S2. Dissolve 10 parts of coating material in water, then add 0.01 parts of coating inducer and mix well to prepare a coating agent. Use the coating agent to spray-coat the particles obtained in S1 and dry them to prepare the granules.

[0028] Specifically, in S1, granules are formed by a single-screw extrusion granulator.

[0029] Specifically, the filler is kaolin and / or diatomaceous earth filter aid.

[0030] Preferably, the filler is a kaolin and diatomaceous earth filter aid.

[0031] In a specific embodiment of the present invention, the mass ratio of the kaolin and diatomaceous earth filter aid is 3:1.

[0032] Specifically, the matrix in the filler attractant is wheat flour or corn flour, and the attractant is erythritol or thiamethoxam dimethyl-β-propionate.

[0033] Preferably, the matrix in the filler attractant is wheat flour, and the attractant is erythritol.

[0034] In a specific embodiment of the present invention, the mass ratio of the matrix to the attractant is 20:1.

[0035] Specifically, the adhesive is pregelatinized starch or carboxymethyl cellulose.

[0036] In a specific embodiment of the present invention, the adhesive is pregelatinized starch.

[0037] Specifically, the coating material is sodium lignosulfonate or polyethylene glycol monomethacrylate.

[0038] Preferably, the coating material is polyethylene glycol monomethacrylate.

[0039] Specifically, the encapsulation inducer is erythritol or thiatin dimethyl-β-propionic acid.

[0040] Preferably, the encapsulation inducer is erythritol.

[0041] This invention seeks protection for the tetraacetal granules prepared using the above-described preparation method, which possess both attractant and waterproof properties.

[0042] Optionally, the particle size of the metaldehyde granules is 0.5 to 1.5 mm.

[0043] The present invention also claims protection for the use of the aforementioned metaldehyde granules in the preparation of products for the prevention and control of harmful mollusks.

[0044] Specifically, the harmful mollusc is the golden apple snail.

[0045] The present invention has the following beneficial effects:

[0046] This invention prepares a metaldehyde granule formulation that combines attraction and water resistance by mixing metaldehyde with filler, filler attractant, and binder, then granulating the mixture using a single-screw extruder. The granules are then spray-coated with a coating agent containing polyethylene glycol monomethacrylate or sodium lignosulfonate and dried. Testing shows that the metaldehyde granule formulation of this invention not only has a strong attraction to golden apple snails, but also, upon contact with water, the metaldehyde in the granule is not quickly released into the water, allowing for a long-lasting killing effect on golden apple snails and promoting efficient control. Detailed Implementation

[0047] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0048] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0049] Example 1: Preparation of metaldehyde granules with both attraction and water resistance

[0050] The metaldehyde granules described in this embodiment, which combine attraction and water resistance, are referred to as granules 1. These granules are prepared by spraying a coating agent made of coating material and coating attractant onto granules made of metaldehyde, fillers (diatomaceous earth filter aid and kaolin), filler attractant (matrix and attractant), and binder, followed by drying. The preparation method is as follows:

[0051] S1. Mix 6.00 g metaldehyde, 10.00 g diatomaceous earth filter aid, 33.00 g kaolin, 20.00 g matrix (wheat flour), 1.00 g attractant (erythritol) and 20.00 g binder (pregelatinized starch) with water and granulate them into granules by single screw extrusion granulation.

[0052] S2. Dissolve 10.00 g of coating material (polyethylene glycol monomethacrylate) in 40.00 g of water, then add 0.01 g of coating inducer (erythritol) and mix evenly to prepare a coating agent. Use the coating agent to spray-coat the particles obtained in S1 and dry them to obtain granule 1.

[0053] Example 2: Preparation of metaldehyde granules with both attraction and water resistance properties

[0054] The metaldehyde granules described in this embodiment, which combine attraction and water resistance, are referred to as granules 2. The difference between granules 1 and those described in Example 1 is that the attractant and the coating attractant used are different.

[0055] The preparation method of the granule 2 is as follows:

[0056] S1. Mix 6.00 g metaldehyde, 10.00 g diatomaceous earth filter aid, 33.00 g kaolin, 20.00 g matrix (wheat flour), 1.00 g attractant (dimethyl-β-propionate thiatin) and 20.00 g binder (pregelatinized starch) with water and granulate by single screw extrusion granulation.

[0057] S2. Dissolve 10.00 g of coating material (polyethylene glycol monomethacrylate) in 40.00 g of water, then add 0.01 g of coating inducer (dimethyl-β-propionate thiatin) and mix evenly to prepare a coating agent. Use the coating agent to spray-coat the particles obtained in S1 and dry them to obtain granule 2.

[0058] Example 3: Preparation of metaldehyde granules with both attraction and water resistance

[0059] The tetraacetal granules described in this embodiment, which combine attraction and water resistance, are referred to as granules 3. The difference between granules 3 and granules 1 described in Example 1 is that the coating material used is different.

[0060] The preparation method of the granule 3 is as follows:

[0061] S1. Mix 6.00 g metaldehyde, 10.00 g diatomaceous earth filter aid, 33.00 g kaolin, 20.00 g matrix (wheat flour), 1.00 g attractant (erythritol) and 20.00 g binder (pregelatinized starch) with water and granulate them into granules by single screw extrusion granulation.

[0062] S2. Dissolve 10.00 g of coating material (sodium lignosulfonate) in 40.00 g of water, then add 0.01 g of coating inducer (erythritol) and mix evenly to prepare a coating agent. Use the coating agent to spray-coat the granules obtained in S1 and dry them to obtain granule 3.

[0063] Example 4: Preparation of metaldehyde granules with both attraction and water resistance

[0064] The tetraacetal granules described in this embodiment, which combine attraction and water resistance, are referred to as granules 4. The difference between granules 4 and granules 1 described in Example 1 is that the amount of kaolin used is different, at 28.00 g; the amount of coating material used is different, at 15.00 g. That is, by adjusting the amount of kaolin used, the total mass of raw materials used is kept consistent with that in Example 1.

[0065] The preparation method of the granule 4 is as follows:

[0066] S1. Mix 6.00 g metaldehyde, 10.00 g diatomaceous earth filter aid, 28.00 g kaolin, 20.00 g matrix (wheat flour), 1.00 g attractant (erythritol) and 20.00 g binder (pregelatinized starch) with water and granulate them into granules by single screw extrusion granulation.

[0067] S2. Dissolve 15.00 g of coating material (polyethylene glycol monomethacrylate) in 40.00 g of water, then add 0.01 g of coating inducer (erythritol) and mix evenly to prepare a coating agent. Use the coating agent to spray-coat the particles obtained in S1 and dry them to obtain granules 4.

[0068] Example 5: Preparation of metaldehyde granules with both attraction and water resistance

[0069] The tetraacetal granules described in this embodiment, which combine attraction and water resistance, are designated as granules 5. The difference between granules 5 and granules 1 described in Example 1 is that the amount of kaolin used is different, being 38.00 g; and the amount of coating material used is different, being 5.00 g.

[0070] The preparation method of the granule 5 is as follows:

[0071] S1. Mix 6.00 g metaldehyde, 10.00 g diatomaceous earth filter aid, 38.00 g kaolin, 20.00 g matrix (wheat flour), 1.00 g attractant (erythritol) and 20.00 g binder (pregelatinized starch) with water and granulate them into granules by single screw extrusion granulation.

[0072] S2. Dissolve 5.00 g of coating material (polyethylene glycol monomethacrylate) in 40.00 g of water, then add 0.01 g of coating inducer (erythritol) and mix evenly to prepare a coating agent. Use the coating agent to spray-coat the particles obtained in S1 and dry them to obtain granule 5.

[0073] Comparative Example 1

[0074] Granules were prepared according to the preparation method described in Example 1, and are referred to as granules 6. The difference between granules 6 and granules 1 described in Example 1 is that the granules do not contain attractants and coating attractants, and the amount of kaolin is adjusted to 34.00 g.

[0075] Comparative Example 2

[0076] Granules were prepared according to the preparation method described in Example 1, and are referred to as granules 7. The difference between granules 7 and granules 1 described in Example 1 is that the granules do not contain a coating inducer.

[0077] Comparative Example 3

[0078] Granules were prepared according to the preparation method described in Example 1, and are referred to as granules 8. The difference between granules 8 and granules 1 described in Example 1 is that the granules do not contain coating materials and coating inducers, and the amount of kaolin is adjusted to 43.00 g.

[0079] Test Example 1: Seduction Effect Test

[0080] This invention tested the attraction effect of the granules prepared in Examples 1-5 and Comparative Examples 1-3 on golden apple snails after soaking in water for different times through an attraction experiment.

[0081] 10 g of granules (1-8) and 30 golden apple snails (Pelodiscus sinensis) wrapped in mesh were placed in the same corner of a 20 L rectangular container. After soaking for different times (1, 5, 24, 72 h), the number of golden apple snails gathered near the mesh was observed. The percentage of golden apple snails attracted (golden apple snail attraction rate) was obtained by dividing the number of golden apple snails by the total number of golden apple snails in the sealed container. The experiment was repeated three times.

[0082] Table 1 Results of the seduction effect test

[0083]

[0084] Note: Different lowercase letters in the table indicate significant differences.

[0085] The results of the attraction effects of granules 1-8 on golden apple snails are shown in Table 1. Table 1 shows that granule 1 had a significantly higher attraction rate for golden apple snails after soaking for 1 h, 5 h, and 72 h than granule 6, indicating that erythritol, as both an attractant and a coating attractant, significantly improved the attraction of the granules to golden apple snails. Granule 1 had a significantly higher attraction rate for golden apple snails after soaking for 1 h and 5 h than granule 7, but the attraction rate after soaking for 24 h and 72 h was not significantly different from that of granule 2, indicating that adding a coating attractant can improve the initial attraction of the granules to golden apple snails.

[0086] Granule 1 showed a significantly higher attraction rate to golden apple snails after soaking for 1 h, 5 h, and 72 h than granule 2, indicating that erythritol is more effective than dimethyl-β-propionate thiatin in attracting golden apple snails.

[0087] The attraction rate of granules 1 to golden apple snails after soaking for 1 h and 5 h was not significantly different from that of granules 3, indicating that sodium lignosulfonate can also be used as a coating material.

[0088] Granule 1 showed a significantly higher attraction rate to golden apple snails after soaking for 1 h, 5 h, and 72 h than granule 4. However, its attraction rate to golden apple snails after soaking for 1 h and 5 h was not significantly different from that of granule 5. This indicates that when the amount of polyethylene glycol monomethacrylate (as a percentage of the granule mass) is 15%, it will significantly reduce the attraction of the granules to golden apple snails. The effect is better when the amount is in the range of 5% to 10%.

[0089] Test Example 2: Waterproofing Performance Test

[0090] This invention tested the waterproofing effect of granules 1-8. The test method is as follows:

[0091] 10 g of granules were placed in a cylindrical container, 20 L of water was added, and the container was kept in a constant temperature (25±1℃) environment for 1 day and 3 days respectively. After removal, the granules were dried at 45℃. Liquid phase tests were performed on the granules that were not soaked, the granules soaked for 1 day, and the granules soaked for 3 days. The residual rate of granules soaked for the corresponding time was calculated by dividing the acetaldehyde content in the granules soaked for the corresponding time by the acetaldehyde content in the granules that were not soaked. The waterproof effect of granules 1 to 8 was evaluated by this method. The experiment was repeated three times.

[0092] Table 2 Waterproofing effect test results

[0093]

[0094] Note: Different lowercase letters in the table indicate significant differences.

[0095] The waterproofing effect test results of granules 1-8 are shown in Table 2. Table 2 shows that after 1 day and 3 days of immersion, the residual rate of metaldehyde in granules 1-7 was significantly higher than that in granule 8, indicating that polyethylene glycol monomethacrylate or sodium lignosulfonate as coating materials can significantly improve the waterproofing effect of the granules and increase the residual amount of metaldehyde after immersion. Specifically, the residual rate of metaldehyde in granules 1, 2, and 4 was significantly higher than that in granule 3, while the residual rate of metaldehyde in granule 5 was comparable to that in granule 3. This indicates that compared to sodium lignosulfonate, polyethylene glycol monomethacrylate can significantly improve the waterproofing effect of the granules and increase the residual amount of metaldehyde after immersion.

[0096] Test Example 3: Efficacy Test

[0097] This invention tested the efficacy of granules 1-8 against *Pomacea canaliculata* through small-scale trials. The plots were selected at 2 m... 2 The planting box was covered with 5 cm of soil at the bottom and a 10 cm water layer on top. Fifty uniformly sized (2.5–3.5 cm) golden apple snails were evenly placed inside. Then, the same dosage (1 kg / 667 m³) was evenly sprinkled into each box. 2 The dosage of granules (1-8) was applied by spreading. Results were examined at 3, 5, and 7 days after application, and the mortality rate of golden apple snails was recorded. The experiment was repeated 3 times.

[0098] Table 3. Results of drug efficacy tests

[0099]

[0100] Note: Different lowercase letters in the table indicate significant differences.

[0101] The efficacy test results of granules 1-8 on *Pomacea canaliculata* are shown in Table 3. Table 3 shows that 3 days after application, the mortality rate of *Pomacea canaliculata* treated with granule 1 was significantly higher than that treated with granule 7. Furthermore, 7 days after application, the mortality rate of *Pomacea canaliculata* treated with granule 1 was still significantly higher than that treated with granule 7. This indicates that adding the capsulating attractant can significantly increase the mortality rate of *Pomacea canaliculata* in the early stages of application, and the difference is also significant at 7 days.

[0102] The mortality rate of golden apple snails in granule 1 was significantly higher than that in granule 2 at 3, 5 and 7 days after application, indicating that erythritol was more effective as an attractant and in attractant for encapsulation than thiamethoxam dimethyl-β-propionate.

[0103] The mortality rate of golden apple snails in granule 1 was significantly higher than that in granules 3, 5, and 7 days after application. At 5 and 7 days after application, the mortality rate of golden apple snails in granule 3 was significantly higher than that in granule 8. This indicates that the coating materials polyethylene glycol monomethacrylate and sodium lignosulfonate significantly improve the efficacy of granules in controlling golden apple snails, and the efficacy-enhancing effect of polyethylene glycol monomethacrylate is greater than that of sodium lignosulfonate.

[0104] The mortality rate of golden apple snails in granule 1 was significantly higher than that in granule 5 at 3, 5 and 7 days after application, although the difference was small. However, the mortality rate of golden apple snails in granule 5 was significantly higher than that in granule 4, indicating that the amount of coating material affects the efficacy of the prepared granules. When the amount of polyethylene glycol monomethacrylate coating material is in the range of 5% to 10%, the effect is relatively better.

[0105] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a metaldehyde granule that combines attraction and water resistance, characterized in that, Includes the following steps: S1. Mix 4-8 parts of metaldehyde, 35-45 parts of filler, 18-24 parts of filler attractant and 18-22 parts of binder with water to form granules; S2. Dissolve 5-10 parts of coating material in water, then add 0.01-0.03 parts of coating inducer and mix well to prepare a coating agent. Use the coating agent to spray-coat the particles obtained in S1 and dry them to prepare the granules. The filler material is diatomaceous earth filter aid; The filler attractant consists of a matrix and an attractant, with a matrix-to-attractant mass ratio of 22-28:1; the matrix is ​​wheat flour; the attractant is erythritol and / or thiamethoxam dimethyl-β-propionate. The adhesive is pregelatinized starch; The coating material is sodium lignosulfonate and / or polyethylene glycol monomethacrylate; The encapsulation attractant is erythritol and / or thiatin dimethyl-β-propionic acid.

2. The preparation method according to claim 1, characterized in that, Includes the following steps: S1. Mix 5-7 parts of metaldehyde, 38-42 parts of filler, 20-22 parts of filler attractant and 18-22 parts of binder with water to form granules; S2. Dissolve 8-10 parts of coating material in water, then add 0.01-0.02 parts of coating inducer and mix well to prepare a coating agent. Use the coating agent to spray-coat the particles obtained in S1 and dry them to prepare the granules.

3. The preparation method according to claim 1, characterized in that, The attractant is erythritol or thiamethoxam dimethyl-β-propionic acid.

4. The preparation method according to claim 1, characterized in that, The coating material is sodium lignosulfonate or polyethylene glycol monomethacrylate.

5. The preparation method according to claim 1, characterized in that, The encapsulation inducer is erythritol or thiamethoxam dimethyl-β-propionic acid.

6. The tetraacetal granules prepared by any one of the preparation methods described in claims 1 to 5, which combine attraction and water resistance.

7. The use of the tetraacetaldehyde granules according to claim 6 in the preparation of products for the prevention and control of harmful mollusks.

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