Coating type polyolefin dripping agent and preparation method thereof

Abstract

The invention relates to the field of agricultural production, and particularly discloses a coating type polyolefin dripping agent and a preparation method thereof. The invention discloses a coating type polyolefin dripping agent which is prepared from the following raw materials in parts by weight: 10 to 18 parts of acrylic polymer, 4 to 6 parts of polysiloxane, 3 to 5 parts of modified nano silicon dioxide, 1 to 2 parts of anti-ultraviolet absorbent, 5 to 8 parts of polyoxyethylene polyoxypropylene ether, 20 to 30 parts of water, 8 to 18 parts of nonionic fluorocarbon surfactant and 2 to 4 parts of phthalate coupling agent. The modified nano silicon dioxide is obtained by modifying nano silicon dioxide with lauroyl diethanolamide. The composition provided by the invention can be used for surface coating of polyolefin films, and has the advantages of good dripping property and long lasting effect.

Description

Technical Field

[0001] The present application relates to the field of agricultural production, and more specifically, to a coating type polyolefin dripping agent and a preparation method thereof. Background Art

[0002] Coated polyolefin dripping agent is a functional additive widely used in agricultural greenhouse films and packaging materials. By coating on the surface of polyolefin film, it can significantly improve the dripping performance of the film, effectively prolong the spreading time of water droplets on the film surface, reduce the formation of dew, thereby enhancing light transmittance, improving the light intensity and uniformity in the greenhouse, and promoting crop growth. It also helps to reduce the fog caused by the temperature difference between the inside and outside of the film, and improve the yield and quality of crops. In addition, this type of dripping agent also has excellent weather resistance and durability, can maintain the dripping effect for a certain period of time, reduce the frequency of film replacement, and reduce agricultural production costs.

[0003] At present, the common coating polyolefin dripping agents on the market are mainly composed of specific surfactants, film-forming aids, stabilizers and solvents, etc., which are coated on the surface of polyolefin film through a specific process and form a uniform dripping layer after drying and curing. However, the coating polyolefin dripping agents in the prior art still have some shortcomings in practical applications. For example, when some dripping agents are combined with polyolefin films, their adhesion is insufficient and they fall off during use, affecting the durability of the dripping effect.

[0004] Therefore, it is necessary to prepare a long-lasting coating polyolefin dripping agent. Summary of the invention

[0005] In order to improve the long-term effectiveness of the dripping agent, the present application provides a coated polyolefin dripping agent and a preparation method thereof.

[0006] In the first aspect, the present application provides a coated polyolefin dripping agent and a preparation method thereof, which adopts the following technical scheme: A coating type polyolefin dripping agent and a preparation method thereof, comprising the following raw materials in parts by weight: 10-18 parts of acrylic polymer, 4-6 parts of polysiloxane, 3-5 parts of modified nano-silica, 1-2 parts of anti-ultraviolet absorber, 5-8 parts of polyoxyethylene polyoxypropylene ether, 20-30 parts of water, 8-18 parts of nonionic fluorocarbon surfactant and 2-4 parts of phthalate coupling agent. The modified nano-silica is obtained by modifying nano-silica with lauric acid diethanolamide.

[0007] By adopting the above technical scheme, nano-silicon dioxide as an inorganic nano-filler can increase the film-forming property and wear resistance of the dripping agent, and at the same time improve the roughness of the film surface, which is conducive to the uniform distribution and rapid flow of water droplets; further modification by lauric acid diethanolamide not only improves its dispersion uniformity in the dripping agent, but also improves its compatibility with polyolefin film, making the dripping agent more stable and durable. Acrylic polymer as the main body of the dripping agent has good film-forming property and adhesion, and can be evenly and firmly coated on the surface of polyolefin film, providing a solid foundation for the realization of the dripping effect. The addition of two non-ionic surfactants, polyoxyethylene polyoxypropylene ether and non-ionic fluorocarbon surfactant, can significantly reduce the surface tension of the film, improve the wettability and spreadability of the dripping agent, make it evenly cover the surface of the substrate, and improve the coverage effect and dripping performance of the dripping agent.

[0008] The unique structure of polysiloxane gives it low surface energy and excellent lubricity, which can effectively reduce the contact angle between water droplets and the surface of the dripping agent, promote the rapid flow of water droplets, improve the dripping effect, and reduce the residual water droplets on the surface of the film. In addition, the modified nano-silica particles work synergistically with the anti-ultraviolet absorber to effectively slow down the aging of the dripping agent by anti-oxidation and reflecting ultraviolet rays, further improving the effectiveness of the dripping agent.

[0009] Optionally, the preparation of the modified nano-silicon dioxide comprises the following steps: (1) taking nano-silica and putting it into anhydrous ethanol and water, stirring and mixing, ultrasonically dispersing, adding 3-aminopropyltriethoxysilane, heating to 70-80° C., reacting for 3-5 hours, filtering, and drying to obtain amino-modified nano-silica powder; (2) dissolving lauric acid diethanolamide in deionized water, adding the amino-modified nano-silica powder, adding hydrochloric acid to adjust the pH to 3.6-4, stirring at a constant speed at 70-80° C. for 8-10 hours, and obtaining the modified nano-silica through concentration and freeze-drying.

[0010] By adopting the above technical scheme, the reaction activity of silicon dioxide is improved through the preliminary amination reaction to provide a good reaction basis for the subsequent modification reaction, and lauric acid diethanolamide is further added to modify the amination silicon dioxide. The modified nano-silica particles contain a large number of hydroxyl groups and have strong hydrophilicity, which improves the dripping performance of the dripping agent. At the same time, the long-chain alkyl structure on the lauric acid diethanolamide further strengthens the adhesion with the polyolefin film to improve the long-term effectiveness of the dripping agent.

[0011] Optionally, in the preparation process, the weight ratio of nano-silicon dioxide to 3-aminopropyltriethoxysilane is 4:0.8-1.

[0012] Optionally, in the preparation step (2), the weight ratio of lauric acid diethanolamide to amino-modified nano-silica is 2-3:1.

[0013] Optionally, the particle size of the nano-silicon dioxide is 20-30 μm.

[0014] By adopting the above technical solution, the silica within this particle size range has a large specific surface area and good dispersibility, which helps to improve the wettability of the material, optimize the dripping performance of the dripping agent, and ensure that water droplets can flow along both sides of the membrane surface to the ground.

[0015] Optionally, the anti-ultraviolet absorber is a salicylate anti-ultraviolet absorber.

[0016] By adopting the above technical scheme, the salicylate anti-ultraviolet absorber has a certain surface activity and can improve the wettability of the drip agent. The hydrophilic groups and hydrophobic groups in its molecular structure help to reduce the interfacial tension between water droplets and the surface of the polyolefin film layer, and improve the spreading of the drip agent on the surface of the film layer, thereby further improving the drip performance.

[0017] Optionally, the raw materials further include 1-3 parts of divinyl-1,4-butanediol ether.

[0018] By adopting the above technical solution, the addition of divinyl-1,4-butanediol ether can further enhance the adhesion between the dripping agent and the polyolefin substrate. It can interact with the polyolefin surface to form a strong chemical bond and physical adsorption, so that the dripping agent is more tightly attached to the film and the long-term effect of the dripping agent is improved.

[0019] In a second aspect, the present application provides a method for preparing a coated polyolefin dripping agent, using the following technical solution: A method for preparing a coating type polyolefin dripping agent comprises the following steps: Step 1. Ultrasonically disperse the modified nano-silica uniformly in water to obtain a modified nano-silica aqueous dispersion for use; Step 2. Take acrylic polymer, polysiloxane, polyoxyethylene polyoxypropylene ether, anti-ultraviolet absorber, non-ionic fluorocarbon surfactant and phthalate coupling agent, add them to the modified nano-silica aqueous dispersion and stir to mix evenly to obtain a coating type polyolefin dripping agent.

[0020] In summary, this application has the following beneficial effects: 1. The present invention significantly improves the flow rate and uniformity of water droplets on the surface of polyolefin film. The addition of modified nano-silica not only increases the roughness of the film surface, but also facilitates the uniform distribution and rapid flow of water droplets. At the same time, the combined effect of polysiloxane, nonionic surfactant, divinyl-1,4-butanediol ether and other ingredients further enhances the adhesion of the dripping agent to the polyolefin substrate, making the dripping effect more durable and stable.

[0021] 2. This application further improves the antioxidant properties of the drip agent through the synergistic effect of modified nano-silica and anti-ultraviolet absorbers, making the drip agent not only suitable for conventional polyolefin films, but also for occasions with higher requirements for weather resistance, such as outdoor agricultural sheds, greenhouses, etc. DETAILED DESCRIPTION

[0022] The present application is further described in detail below with reference to the embodiments.

[0023] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0024] The nonionic fluorocarbon surfactant model is Capstone FS-30 from Chemours, USA; the acrylic acid polymer is purchased from Guangzhou Taili Chemical Co., Ltd., model 940 Carbomer; and the polysiloxane is purchased from Jinan Yingyu Chemical Co., Ltd., model 204.

[0025] Preparation examples of raw materials and / or intermediates Preparation Example 1 A modified silicon dioxide, the preparation of which comprises the following steps: (1) 8 kg of nano-silica was added into 4 kg of anhydrous ethanol and 1 kg of water and stirred to mix evenly, and then placed in an ultrasonic cleaning machine for ultrasonic vibration dispersion for 2 h, and then 2 kg of 3-aminopropyltriethoxysilane was added. The temperature was raised to 75° C. in a water bath and stirred for reaction for 4 h, and then filtered. The filter cake was dried in a vacuum oven at 60° C. to obtain amino-modified nano-silica powder; (2) Dissolve 10 kg of lauric acid diethanolamide in 10 kg of deionized water, add 5 kg of the above-mentioned amino-modified nano-silica powder, add 0.5 mol / L of hydrochloric acid to adjust the pH to 3.6, stir at a constant speed at 80° C. for 8 h, and obtain the modified nano-silica through concentration and freeze-drying; the particle size of the nano-silica is 20-30 μm.

[0026] Preparation Example 2 A modified silicon dioxide, the preparation of which comprises the following steps: (1) 8 kg of nano-silica was added into 4 kg of anhydrous ethanol and 1 kg of water, and stirred to mix evenly. The mixture was then placed in an ultrasonic cleaning machine for ultrasonic vibration dispersion for 2 h, and 1.8 kg of 3-aminopropyltriethoxysilane was added. The mixture was heated to 70° C. in a water bath and stirred for reaction for 5 h. The mixture was then filtered and the filter cake was dried in a vacuum oven at 60° C. to obtain amino-modified nano-silica powder. (2) Dissolve 12 kg of lauric acid diethanolamide in 10 kg of deionized water, add 5 kg of the above-mentioned amino-modified nano-silica powder, add 0.5 mol / L of hydrochloric acid to adjust the pH to 4, stir at a constant speed at 70° C. for 9 hours, and obtain the modified nano-silica through concentration and freeze-drying; the particle size of the nano-silica is 20-30 μm.

[0027] Preparation Example 3 A modified silicon dioxide, the preparation of which comprises the following steps: (1) 8 kg of nano-silica was added into 4 kg of anhydrous ethanol and 1 kg of water and stirred to mix evenly, and then placed in an ultrasonic cleaning machine for ultrasonic vibration dispersion for 2 h, and then 1.6 kg of 3-aminopropyltriethoxysilane was added. The temperature was raised to 80° C. in a water bath and stirred for reaction for 3 h, and then filtered. The filter cake was dried in a vacuum oven at 60° C. to obtain amino-modified nano-silica powder; (2) Dissolve 15 kg of lauric acid diethanolamide in 10 kg of deionized water, add 5 kg of the above-mentioned amino-modified nano-silica powder, add 0.5 mol / L of hydrochloric acid to adjust the pH to 3.8, stir at a constant speed at 75° C. for 10 hours, and obtain the modified nano-silica through concentration and freeze-drying; the particle size of the nano-silica is 20-30 μm.

[0028] Preparation Example 4 A modified silicon dioxide, which is different from Preparation Example 1 in that the particle size of the nano silicon dioxide used in this Preparation Example is 30-40 μm.

[0029] Example 5 A modified silicon dioxide, which is different from Preparation Example 1 in that the particle size of the nano silicon dioxide used in this Preparation Example is 10-20 μm. Example

[0030] Example 1 A coating type polyolefin dripping agent, the preparation of which comprises the following steps: Step 1. Ultrasonically disperse 3 kg of modified nano-silicon dioxide in 25 kg of water to obtain a modified nano-silicon dioxide aqueous dispersion for later use; Step 2. Take 14kg of acrylic polymer, 5kg of polysiloxane, 6.5kg of polyoxyethylene polyoxypropylene ether, 1kg of phenyl salicylate (anti-ultraviolet absorber), 13kg of non-ionic fluorocarbon surfactant and 3kg of isopropyl tri(dioctyl pyrophosphoryl) titanate (phthalate coupling agent) and add them to the modified nano-silica aqueous dispersion and stir and mix evenly to obtain a coated polyolefin drip agent; the modified nano-silica is prepared in Preparation Example 1.

[0031] Example 2 A coating type polyolefin dripping agent, the preparation of which comprises the following steps: Step 1. Ultrasonically disperse 4 kg of modified nano-silicon dioxide in 30 kg of water to obtain a modified nano-silicon dioxide aqueous dispersion for later use; Step 2. Take 18kg of acrylic polymer, 6kg of polysiloxane, 5kg of polyoxyethylene polyoxypropylene ether, 1.5kg of phenyl salicylate (anti-ultraviolet absorber), 8kg of non-ionic fluorocarbon surfactant and 4kg of isopropyl tri(dioctyl pyrophosphoryl) titanate (phthalate coupling agent), add them into the modified nano-silica aqueous dispersion and stir to mix evenly to obtain a coated polyolefin dripping agent. The modified nano-silica is prepared in Preparation Example 3.

[0032] Example 3 A coating type polyolefin dripping agent, the preparation of which comprises the following steps: Step 1. Ultrasonically disperse 5 kg of modified nano-silicon dioxide in 20 kg of water to obtain a modified nano-silicon dioxide aqueous dispersion for later use; Step 2. Take 10kg of acrylic polymer, 4kg of polysiloxane, 8kg of polyoxyethylene polyoxypropylene ether, 2kg of phenyl salicylate (anti-ultraviolet absorber), 18kg of non-ionic fluorocarbon surfactant and 2kg of isopropyl tri(dioctyl pyrophosphoryl) titanate (phthalate coupling agent) and add them to the modified nano-silica aqueous dispersion and stir to mix evenly to obtain a coated polyolefin dripping agent. The modified nano-silica is prepared in Preparation Example 2.

[0033] Example 4 A coated polyolefin dripping agent, which is different from Example 1 in that the modified nano-silicon dioxide used in this example is prepared in Preparation Example 4.

[0034] Example 5 A coated polyolefin dripping agent, which is different from Example 1 in that the modified nano-silicon dioxide used in this example is prepared in Preparation Example 5.

[0035] Example 6 A coating type polyolefin dripping agent, which is different from Example 1 in that the anti-ultraviolet absorber used in this example is 2-hydroxy-4-n-octyloxybenzophenone.

[0036] Example 7 A coating type polyolefin dripping agent, which is different from Example 1 in that the present embodiment further comprises 1 kg of divinyl-1,4-butanediol ether, and the preparation comprises the following steps: Step 1. Ultrasonically disperse 3 kg of modified nano-silicon dioxide in 25 kg of water to obtain a modified nano-silicon dioxide aqueous dispersion for later use; Step 2. Take 14kg of acrylic polymer, 5kg of polysiloxane, 6.5kg of polyoxyethylene polyoxypropylene ether, 1kg of phenyl salicylate (anti-ultraviolet absorber), 13kg of non-ionic fluorocarbon surfactant, 1kg of divinyl-1,4-butanediol ether and 3kg of isopropyl tri(dioctyl pyrophosphoryl) titanate (phthalate coupling agent) and add them to the modified nano-silica aqueous dispersion and stir to mix evenly to obtain a coated polyolefin drip agent; the modified nano-silica is prepared in Preparation Example 1.

[0037] Example 8 A coating type polyolefin dripping agent, which is different from Example 7 in that this embodiment also includes 3 kg of divinyl-1,4-butanediol ether.

[0038] Comparative Example Comparative Example 1 A coated polyolefin dripping agent is different from Example 1 in that unmodified nano-silicon dioxide is added in this comparative example.

[0039] Comparative Example 2 A coated polyolefin dripping agent, which is different from Example 1 in that nano silicon dioxide is added in this comparative example.

[0040] Comparative Example 3 A coating type polyolefin dripping agent, which is different from Example 1 in that polyoxyethylene polyoxypropylene ether and nonionic fluorocarbon surfactant are added in this comparative example.

[0041] Performance testing Detection method / test method The prepared dripping agent was coated on the surface of a polyethylene film and dried as a test piece to test its performance.

[0042] Long-term effect: The film coated with the dripping agent is fixed on a 60℃ constant temperature water bath, with the water surface about 5cm above the film and the ambient temperature at room temperature (23±2)℃. When the dew drop area on the film is ≥30.0%, it is considered to be invalid. The time is recorded, which is the effective period of the dripping agent and serves as a reference for the dripping long-term effect data. Contact angle: measured according to the method specified in GB / T 30693-2014. The water bath temperature was set to a constant temperature of (60±1)℃ in the drip tester. When water mist appeared on the film, the initial contact angle was measured. The contact angle was measured after 6 days in the water bath. Weather resistance test: The test is carried out in accordance with the provisions of GB / T 16422.2-2022. The irradiation method is method A, the irradiance is narrow band (340nm) 0.51W / (m·nm), the temperature is controlled by a black standard thermometer, the exposure cycle uses cycle number 1, and the exposure time is recorded as a reference for weather resistance data when the longitudinal fracture nominal strain retention rate is ≤60%.

[0043] Table 1 Test data Duration of effect / d Initial contact angle / ° Contact angle after 6d / ° Exposure time / h Example 1 114 3.3 3.8 5000 Example 2 112 3.5 4 4980 Example 3 110 3.6 3.9 4990 Example 4 105 4.5 5.2 4950 Example 5 104 4.8 5.5 4930 Example 6 109 4 4.5 4970 Example 7 115 3.3 3.7 5050 Example 8 118 3.2 3.6 5100 Comparative Example 1 89 5.5 7.5 4850 Comparative Example 2 85 6.1 10.8 4800 Comparative Example 3 92 5 5.8 4900 Combining Examples 1-3 and Comparative Examples 1-2 and Table 1, it can be seen that the various data of Examples 1-3 are better than those of Comparative Examples 1-2, indicating that the nano-silica modified by the present application has good compatibility, can improve the adhesion of the dripping agent to the surface of the polyolefin film, and improve the dripping effect and durability with its good wetting properties.

[0044] Combining Examples 1-3 and Comparative Example 3 and Table 1, it can be seen that the data of Examples 1-3 are better than those of Comparative Example 3, indicating that the addition of polyoxyethylene polyoxypropylene ether and nonionic fluorocarbon surfactant helps to reduce the surface tension of the film and improve the dripping performance of the dripping agent.

[0045] It can be seen from Examples 1-5 and Table 1 that the data of Examples 1-3 are better than those of Examples 4-5, indicating that the particle size of nano-silicon dioxide affects the final performance of the dripping agent, and selecting a particle size range of 20-30 μm can further optimize the dripping performance of the dripping agent and improve the lasting effect of the dripping agent.

[0046] Combining Example 1 with Example 6 and Table 1, it can be seen that the various data of Example 1 are better than those of Example 6, indicating that the selection of salicylic acid anti-ultraviolet absorbers can work together with the components in the dripping agent to utilize their ability to reduce the surface tension of the polyolefin film, thereby not only improving the weather resistance of the film layer but also giving the film a long-lasting and effective dripping performance.

[0047] Combining Example 1 with Examples 7-8 and Table 1, it can be seen that the data of Examples 7-8 are better than those of Example 1, indicating that the addition of divinyl-1,4-butanediol ether can further improve the adhesion of the drip agent on the film surface and improve the persistence of the drip agent.

[0048] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A coating type polyolefin dripping agent, characterized in that: The composition comprises the following raw materials in parts by weight: 10-18 parts of acrylic polymer, 4-6 parts of polysiloxane, 3-5 parts of modified nano-silica, 1-2 parts of anti-ultraviolet absorber, 5-8 parts of polyoxyethylene polyoxypropylene ether, 20-30 parts of water, 8-18 parts of nonionic fluorocarbon surfactant and 2-4 parts of phthalate coupling agent. The modified nano-silica is obtained by modifying nano-silica with lauric acid diethanolamide.

2. A coating type polyolefin dripping agent according to claim 1, characterized in that: The modified nano-silicon dioxide preparation comprises the following steps: (1) Nano-silica was placed in anhydrous ethanol and water, stirred and dispersed by ultrasonication, 3-aminopropyltriethoxysilane was added, the temperature was raised to 70-80°C, the reaction lasted for 3-5 hours, and then filtered and dried to obtain amino-modified nano-silica powder; (2) Dissolve lauric acid diethanolamide in deionized water, add the amino-modified nano-silica powder, add hydrochloric acid to adjust the pH to 3.6-4, stir at a constant speed at 70-80° C. for 8-10 hours, and obtain the modified nano-silica after concentration and freeze-drying.

3. A coating type polyolefin dripping agent according to claim 2, characterized in that: In the preparation process, the weight ratio of nano silicon dioxide to 3-aminopropyltriethoxysilane is 4:0.8-1.

4. A coating type polyolefin dripping agent according to claim 2, characterized in that: In the preparation step (2), the weight ratio of lauric acid diethanolamide to amino-modified nano-silica is 2-3:

1.

5. The coating type polyolefin dripping agent according to claim 1, characterized in that: The particle size of the nano silicon dioxide is 20-30 μm.

6. The coating type polyolefin dripping agent according to claim 1, characterized in that: The anti-ultraviolet absorber is a salicylate anti-ultraviolet absorber.

7. The coating type polyolefin dripping agent according to claim 1, characterized in that: The raw materials also include 1-3 parts of divinyl-1,4-butanediol ether.

8. A method for preparing a coating type polyolefin dripping agent according to any one of claims 1 to 7, characterized in that: The steps include: Step 1. Ultrasonically disperse the modified nano-silicon dioxide in water to obtain a modified nano-silicon dioxide aqueous dispersion for later use; Step 2. Take acrylic polymer, polysiloxane, polyoxyethylene polyoxypropylene ether, anti-ultraviolet absorber, non-ionic fluorocarbon surfactant and phthalate coupling agent, add them into the modified nano-silica aqueous dispersion, stir and mix evenly to obtain a coating type polyolefin dripping agent.