Highly stable film-forming material for seed coating and method for preparing the same

Abstract

This invention relates to the field of agricultural seed coating agents, and proposes a highly stable film-forming material for seed coating and its preparation method. The highly stable film-forming material for seed coating comprises the following components in parts by weight: 8-10 parts polyvinyl alcohol, 5-6 parts emulsion, 5-8 parts sodium carboxymethyl cellulose, 1-2 parts anti-settling agent, 8-10 parts humectant, 6-8 parts dispersant, and 80-100 parts water. The anti-settling agent is fumed silica, which is composed of hydrophilic and hydrophobic fumed silica in a mass ratio of 5-6:1. This technical solution solves the problem of insufficient stability in seed coating film-forming materials in related technologies.

Description

Technical Field

[0001] This invention relates to the field of agricultural seed coating technology, specifically to a highly stable film-forming material for seed coating and its preparation method. Background Technology

[0002] Seed coating technology has become a key means to improve seed quality and ensure agricultural production efficiency, and is widely used in the treatment of seeds of staple crops such as corn, rice, and wheat, as well as various cash crops. Film-forming materials for seed coating are a core component of seed coating technology; they are essentially materials that can spread evenly on the seed surface, dry quickly, and form a continuous, dense, and resilient film.

[0003] Currently, the stability of film-forming materials used for seed coating remains insufficient. Film-forming materials with poor stability are prone to solid-liquid separation during static storage, with the lower layer precipitating and agglomerating while the upper layer of clear liquid precipitates out. At the same time, the system is prone to abnormal thickening and large viscosity fluctuations, which can lead to the aggregation of powder particles and agglomeration. In severe cases, flocculation and precipitation may occur, which not only affects the fluidity and uniformity of coating application but also results in uneven coating thickness, discontinuous film formation, and easy peeling and cracking on the seed surface, thus reducing the quality of seed coating.

[0004] Therefore, it is very necessary to develop a highly stable film-forming material for seed coating. Summary of the Invention

[0005] This invention proposes a highly stable film-forming material for seed coating and its preparation method, which solves the problem of insufficient stability of film-forming materials for seed coating in related technologies.

[0006] The technical solution of the present invention is as follows: The present invention proposes a highly stable film-forming material for seed coating, comprising the following raw materials in parts by weight: 8-10 parts of polyvinyl alcohol, 5-6 parts of emulsion, 5-8 parts of sodium carboxymethyl cellulose, 1-2 parts of anti-settling agent, 8-10 parts of humectant, 6-8 parts of dispersant, and 80-100 parts of water. The anti-settling agent is fumed silica, which is composed of hydrophilic fumed silica and hydrophobic fumed silica in a mass ratio of 5-6:1.

[0007] As a further technical solution, the nitrogen adsorption specific surface area of ​​the hydrophilic fumed silica is 240~325m². 2 / g, the nitrogen adsorption specific surface area of ​​the hydrophobic fumed silica is 120~200m². 2 / g.

[0008] In the high-stability film-forming material for seed coating of this invention, the nitrogen adsorption specific surface area of ​​hydrophilic fumed silica is limited to 240~325m². 2The use of hydrophilic fumed silica with a high specific surface area can rapidly construct a dense, continuous three-dimensional network structure in aqueous systems, providing strong and stable anti-settling support, effectively preventing solid particles from settling and ensuring the initial uniformity of the system dispersion; the nitrogen adsorption specific surface area of ​​hydrophobic fumed silica is 120~200m². 2 / g, hydrophobic fumed silica with a low specific surface area can avoid excessive viscosity and dispersion difficulties caused by an excessively high overall specific surface area. Furthermore, it can inhibit particle agglomeration, flocculation, and hard sedimentation in the system through appropriate steric hindrance and hydrophobic repulsion. These two factors work synergistically to improve the stability of film-forming materials used in seed coating.

[0009] As a further technical solution, the polyvinyl alcohol has a weight-average molecular weight of 31,000 to 50,000 and a degree of hydrolysis of 87% to 89%.

[0010] In the high-stability film-forming material for seed coating of this invention, the weight-average molecular weight of polyvinyl alcohol is 31,000-50,000, and the degree of hydrolysis is 87%-89%. Polyvinyl alcohol molecules within this molecular weight range exhibit moderate flexibility, enabling them to rapidly fuse and spread uniformly with components such as sodium carboxymethyl cellulose and composite emulsions, forming a continuous, dense, and smooth coating layer on the seed surface. The 87%-89% degree of hydrolysis provides a suitable hydrophilic-hydrophobic balance, making it less prone to shrinkage, wrinkling, and cracking during film formation, resulting in good film integrity.

[0011] As a further technical solution, the emulsion is composed of styrene-acrylic emulsion and silicone-acrylic emulsion in a mass ratio of 2 to 4:1.

[0012] In this invention, the high-stability film-forming material for seed coating comprises an emulsion of styrene-acrylic emulsion and silicone-acrylic emulsion. The styrene-acrylic emulsion exhibits excellent film-forming properties, strong adhesion, and good flexibility, allowing it to spread rapidly on the seed surface and form a continuous base film. The silicone-acrylic emulsion has low surface energy and forms a dense, smooth film, effectively improving the film's water resistance, smoothness, and anti-adhesion properties. The combination of these two materials demonstrates good compatibility and a significant synergistic effect, resulting in a continuous, uniform, dense, pinhole-free, and smooth coating film. Simultaneously, it possesses excellent flexibility and adhesion, effectively preventing problems such as cracking, curling, and peeling of the coating film, thus enhancing the film-forming properties of the high-stability film-forming material for seed coating.

[0013] As a further technical solution, the glass transition temperature of the styrene-acrylic emulsion is 15~25℃, and the viscosity is 500~1500mPa·s.

[0014] As a further technical solution, the glass transition temperature of the silicone-acrylic emulsion is 15~25℃, and the viscosity is 500~1500mPa·s.

[0015] As a further technical solution, the humectant includes one or more of propylene glycol, glycerol, and polyethylene glycol, preferably propylene glycol.

[0016] As a further technical solution, the dispersant includes one or two of sodium lignosulfonate and sodium dodecylbenzenesulfonate, preferably sodium lignosulfonate.

[0017] As a further technical solution, the Brookfield viscosity of the sodium carboxymethyl cellulose is 300~800 mPa·s.

[0018] This invention also proposes a method for preparing a highly stable film-forming material for seed coating, comprising the following steps: S1. Mix the water, dispersant, humectant, and anti-settling agent evenly to obtain a mixture; S2. Add the polyvinyl alcohol, emulsion and sodium hydroxymethyl cellulose to the mixture, mix evenly, and obtain the highly stable film-forming material for seed coating.

[0019] The working principle and beneficial effects of this invention are as follows: In this invention, a highly stable film-forming material for seed coating is produced by combining hydrophilic and hydrophobic fumed silica as anti-settling agents. The synergistic effect of these two agents enhances the overall stability of the seed coating film-forming material. The hydrophilic fumed silica exhibits excellent dispersibility in aqueous systems, rapidly forming a uniform network structure that effectively inhibits the sedimentation and stratification of raw material components. The hydrophobic fumed silica enhances the system's anti-flocculation and anti-hard sedimentation properties, reducing agglomeration and clumping during long-term storage. This combined use ensures the storage stability of the film-forming material during production, storage, and transportation, while also optimizing the system's thixotropic properties and flow uniformity. This results in uniform dispersion and reduced pore clogging during seed coating, leading to a smoother and denser film and improved overall stability. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise specified, the following embodiments and comparative examples are as follows: Polyvinyl alcohol: weight average molecular weight 31,000~50,000, degree of hydrolysis 87%~89%; Hydrophilic fumed silica: nitrogen adsorption specific surface area is 275~325m² 2 / g, model number HL-300; Hydrophobic fumed silica: nitrogen adsorption specific surface area is 120~160m² 2 / g, model number HB-615; Styrene-acrylic emulsion: Model S-01; Silicone-acrylic emulsion: Model SD-528; Sodium carboxymethyl cellulose: Brookfield viscosity is 300~800 mPa·s.

[0022] Example 1 A highly stable film-forming material for seed coating comprises the following raw materials in parts by weight: 8 parts polyvinyl alcohol, 5 parts emulsion, 5 parts sodium carboxymethyl cellulose, 1 part anti-settling agent, 8 parts propylene glycol, 6 parts sodium lignosulfonate, and 80 parts water. The anti-settling agent is composed of hydrophilic fumed silica and hydrophobic fumed silica in a mass ratio of 5:1. The emulsion is a styrene-acrylic emulsion; A method for preparing a highly stable film-forming material for seed coating includes the following steps: S1. Mix water, propylene glycol, sodium lignosulfonate, and anti-settling agent evenly to obtain a mixture; S2. Add polyvinyl alcohol, emulsion and sodium hydroxymethyl cellulose to the mixture, mix evenly to obtain a highly stable film-forming material for seed coating.

[0023] Example 2 A highly stable film-forming material for seed coating comprises the following raw materials in parts by weight: 9 parts polyvinyl alcohol, 5.5 parts emulsion, 6 parts sodium carboxymethyl cellulose, 1.5 parts anti-settling agent, 9 parts propylene glycol, 7 parts sodium lignosulfonate, and 90 parts water. The anti-settling agent is composed of hydrophilic fumed silica and hydrophobic fumed silica in a mass ratio of 5:1. The emulsion is a styrene-acrylic emulsion; A method for preparing a highly stable film-forming material for seed coating includes the following steps: S1. Mix water, propylene glycol, sodium lignosulfonate, and anti-settling agent evenly to obtain a mixture; S2. Add polyvinyl alcohol, emulsion and sodium hydroxymethyl cellulose to the mixture, mix evenly to obtain a highly stable film-forming material for seed coating.

[0024] Example 3 A highly stable film-forming material for seed coating comprises the following raw materials in parts by weight: 10 parts polyvinyl alcohol, 6 parts emulsion, 8 parts sodium carboxymethyl cellulose, 2 parts anti-settling agent, 10 parts propylene glycol, 8 parts sodium lignosulfonate, and 100 parts water. The anti-settling agent is composed of hydrophilic fumed silica and hydrophobic fumed silica in a mass ratio of 5:1. The emulsion is a styrene-acrylic emulsion; A method for preparing a highly stable film-forming material for seed coating includes the following steps: S1. Mix water, propylene glycol, sodium lignosulfonate, and anti-settling agent evenly to obtain a mixture; S2. Add polyvinyl alcohol, emulsion and sodium hydroxymethyl cellulose to the mixture, mix evenly to obtain a highly stable film-forming material for seed coating.

[0025] Example 4 Compared with Example 2, Example 4 differs in that the anti-settling agent is composed of hydrophilic fumed silica and hydrophobic fumed silica in a mass ratio of 6:1.

[0026] Example 5 The difference between Example 5 and Example 4 is that hydrophilic fumed silica (with a nitrogen adsorption surface area of ​​275~325 m²) is used. 2 / g (model HL-300) was replaced with an equal amount of hydrophilic fumed silica, with a nitrogen adsorption specific surface area of ​​420~480m². 2 / g, model number HL-450.

[0027] Example 6 The difference between Example 6 and Example 4 is that hydrophobic fumed silica (with a nitrogen adsorption specific surface area of ​​120~160m²) is used. 2 / g (model HB-615) was replaced with an equal amount of hydrophobic fumed silica, with a nitrogen adsorption specific surface area of ​​270~330m². 2 / g, model number HB-630.

[0028] Example 7 The difference between Example 7 and Example 4 is that the emulsion is a silicone-acrylic emulsion.

[0029] Example 8 The difference between Example 8 and Example 4 is that the emulsion is composed of styrene-acrylic emulsion and silicone-acrylic emulsion in a mass ratio of 2:1.

[0030] Example 9 The difference between Example 9 and Example 4 is that the emulsion is composed of styrene-acrylic emulsion and silicone-acrylic emulsion in a mass ratio of 4:1.

[0031] Example 10 Compared with Example 9, Example 10 differs in that polyvinyl alcohol (weight average molecular weight of 31,000 to 50,000 and degree of hydrolysis of 87% to 89%) is replaced with an equal amount of polyvinyl alcohol with a weight average molecular weight of 31,000 to 50,000 and degree of hydrolysis of 98% to 99%.

[0032] Example 11 Compared with Example 9, Example 11 differs in that polyvinyl alcohol (weight average molecular weight of 31,000 to 50,000 and degree of hydrolysis of 87% to 89%) is replaced with an equal amount of polyvinyl alcohol with a weight average molecular weight of 9,000 to 10,000 and a degree of hydrolysis of 80%.

[0033] Comparative Example 1 Compared with Example 2, the difference in Comparative Example 1 is that the anti-settling agent is hydrophilic fumed silica.

[0034] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that the anti-settling agent is hydrophobic fumed silica.

[0035] Experimental Example 1 For the high-stability film-forming materials for seed coating prepared in Examples 1-6 and Comparative Examples 1-2, 5 mL was transferred into ampoules, sealed with an alcohol torch, and the ampoules were placed at 55°C for 14 days. The properties of the samples were then observed.

[0036] The test results are shown in Table 1: Table 1 Performance test results of Examples 1-6 and Comparative Examples 1-2

[0037] Table 1 shows that when the anti-settling agent is composed of hydrophilic and hydrophobic fumed silica, the stability of the film-forming material used for seed coating can be improved. The nitrogen adsorption specific surface area of ​​the hydrophilic fumed silica is 240–325 m². 2 / g, the nitrogen adsorption specific surface area of ​​hydrophobic fumed silica is 120~200m². 2 When the concentration is / g, the stability of the seed coating film-forming material is better.

[0038] Experiment Example 2 The high-stability film-forming materials for seed coating prepared in Examples 4 and 7-11 were dropped onto glass slides, cast into films, and allowed to stand at room temperature. The film-forming time and uniformity were observed. After immersing the glass slides coated with the high-stability film-forming materials for seed coating in water for half an hour, the film layers were scraped off and their integrity was observed. They were then classified into the following three grades: Grade I, uniform film formation, and the film scraped from the glass slide after soaking in water for 0.5 hours is intact; Grade II, uniform film formation, but the film scraped off the glass slide after immersion in water for 0.5 hours is incomplete; Grade III: The film-forming agent cannot form a uniform film on the glass slide or cannot be scraped off after film formation.

[0039] The test results are shown in Table 2: Table 2 Performance test results of Examples 4 and 7-11

[0040] Table 2 shows that when the emulsion is composed of styrene-acrylic emulsion and silicone-acrylic emulsion, the film-forming properties of the seed coating film-forming material can be improved. When the weight-average molecular weight of polyvinyl alcohol is 31,000~50,000 and the degree of hydrolysis is 87%~89%, the film-forming properties of the obtained seed coating film-forming material are even better.

[0041] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A highly stable film-forming material for seed coating, characterized in that, The raw materials include the following components by weight: 8-10 parts polyvinyl alcohol, 5-6 parts emulsion, 5-8 parts sodium carboxymethyl cellulose, 1-2 parts anti-settling agent, 8-10 parts humectant, 6-8 parts dispersant, and 80-100 parts water. The anti-settling agent is fumed silica, which is composed of hydrophilic fumed silica and hydrophobic fumed silica in a mass ratio of 5-6:

1.

2. The highly stable film-forming material for seed coating according to claim 1, characterized in that, The hydrophilic fumed silica has a nitrogen adsorption specific surface area of ​​240~325m². 2 / g, the nitrogen adsorption specific surface area of ​​the hydrophobic fumed silica is 120~200m². 2 / g.

3. The highly stable film-forming material for seed coating according to claim 1, characterized in that, The polyvinyl alcohol has a weight-average molecular weight of 31,000 to 50,000 and a degree of hydrolysis of 87% to 89%.

4. The highly stable film-forming material for seed coating according to claim 1, characterized in that, The emulsion is composed of styrene-acrylic emulsion and silicone-acrylic emulsion in a mass ratio of 2 to 4:

1.

5. The highly stable film-forming material for seed coating according to claim 4, characterized in that, The glass transition temperature of the styrene-acrylic emulsion is 15~25℃, and the viscosity is 500~1500mPa·s.

6. The highly stable film-forming material for seed coating according to claim 4, characterized in that, The glass transition temperature of the silicone-acrylic emulsion is 15~25℃, and the viscosity is 500~1500mPa·s.

7. The highly stable film-forming material for seed coating according to claim 1, characterized in that, The humectant includes one or more of propylene glycol, glycerol, and polyethylene glycol.

8. The highly stable film-forming material for seed coating according to claim 1, characterized in that, The dispersant includes one or both of sodium lignosulfonate and sodium dodecylbenzenesulfonate.

9. A highly stable film-forming material for seed coating according to claim 1, characterized in that, The Brookfield viscosity of the sodium carboxymethyl cellulose is 300~800 mPa·s.

10. A method for preparing a highly stable film-forming material for seed coating, used to prepare the highly stable film-forming material for seed coating as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Mix the water, dispersant, humectant, and anti-settling agent evenly to obtain a mixture; S2. Add the polyvinyl alcohol, emulsion and sodium hydroxymethyl cellulose to the mixture, mix evenly, and obtain the highly stable film-forming material for seed coating.

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