Polyether modified hydroxyl-terminated dyed vegetable oil polyol coating material and application thereof

Abstract

The invention discloses a polyether modified hydroxyl-terminated and dyed vegetable oil polyol coating material and application thereof, and the polyether modified hydroxyl-terminated and dyed vegetable oil polyol coating material is prepared from a basic membrane material, polyether polyol and hydroxyl-terminated dye, the basic membrane material is prepared from castor oil-based polyol and isocyanate in a mass ratio of (1-2): 1; the polyether polyol accounts for 10-15% of the mass of the basic membrane material, and the hydroxyl-terminated dye accounts for 5-15% of the mass of the basic membrane material. Castor oil-based polyol, isocyanate, polyether polyol and a hydroxyl-terminated dye are compounded to prepare a coating material, the castor oil-based polyol and the polyether polyol react with isocyanate to form a soft and hard segment structure of polyurethane, and the introduction of the hydroxyl-terminated dye promotes cross-linking between chains to form an interpenetrating network structure, so that the cross-linked polyurethane film has a good heat-resistant property, and the heat-resistant property of the coating material is improved. The mechanical property and the stability of the material are improved, the flexibility, the hardness, the wear resistance and the functionality of the coating material can be accurately controlled by adjusting the proportion of all the components, and the requirement of fertilizer coating for high performance is met.

Description

Technical Field

[0001] The invention relates to the technical field of production of coated slow-release fertilizers, and in particular to a polyether-modified hydroxyl-terminated vegetable oil polyol coating material and application thereof. Background Art

[0002] In modern agricultural production, fertilizer application is a key link in improving crop yield and quality. However, in the actual fertilization process, fertilizer particles are often transported, rubbed and impacted by mechanical fertilization equipment, which can easily cause the particles to pulverize, break or wear. This phenomenon not only leads to uneven distribution of fertilizer particles, but also may reduce fertilizer utilization and increase agricultural production costs. At the same time, the damage of fertilizer particles may also cause dust pollution, which has adverse effects on the environment and the health of operators.

[0003] In order to reduce particle breakage and dust pollution, coating technology is currently widely used to protect fertilizer particles. The coating material can form a protective layer on the surface of the particles to improve the wear resistance and mechanical strength of the particles. However, the existing fertilizer coating materials mainly include polyvinyl alcohol and wax material coating materials, inorganic mineral coatings, pure polyurethane materials and bio-based materials, but they still have many shortcomings in terms of wear resistance: polyvinyl alcohol and wax materials are often used for coating fertilizer particles, but under the high-intensity friction and impact of mechanical fertilization equipment, they are prone to wear, cracks or peeling, which leads to coating failure and fertilizer particle breakage, affecting the slow-release performance and uniform application of the fertilizer; inorganic mineral coatings such as bentonite, talcum powder and other inorganic materials, although low in cost, have poor wear resistance and are easy to fall off during the fertilization process, and cannot provide effective Effective protection; although pure polyurethane materials have good mechanical strength and weather resistance, their adhesion to fertilizer particles is poor, which causes the coating to easily fall off during fertilization, reducing the utilization rate of fertilizers; bio-based materials mainly include starch-based and cellulose-based materials and aliphatic polyester materials. Starch-based and cellulose-based materials have environmental protection characteristics, but their mechanical strength and wear resistance are low. During mechanical fertilization, the coating is easy to break or be worn, and cannot effectively protect the fertilizer particles; aliphatic polyester materials such as polylactic acid materials, although they have certain mechanical strength, their wear resistance still cannot meet the requirements of high-intensity fertilization equipment. The above problems seriously affect the use effect of fertilizer particles and limit the improvement of agricultural production efficiency. Therefore, it is urgent to develop a new type of coating material with good wear resistance to solve the problems in the prior art. Summary of the invention

[0004] In view of the above-mentioned prior art, the object of the present invention is to provide a polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material and its application.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] The first aspect of the present invention provides a polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material, which is prepared from a base film material, a polyether polyol and a terminal hydroxyl dye, wherein the base film material is composed of a castor oil-based polyol and an isocyanate in a mass ratio of (1-2):1;

[0007] The polyether polyol accounts for 10-15% of the base film material, and the terminal hydroxyl dye accounts for 5-15% of the base film material.

[0008] Preferably, the terminal hydroxyl dye is 1-amino-4-hydroxy-2-(6-hydroxyhexyloxy) anthraquinone.

[0009] Preferably, the polyether polyol is one or more of polyethylene glycol (PEG), polytetramethylene glycol (PTMEG) and polypropylene glycol (PPG).

[0010] Preferably, the isocyanate is polyaryl polyisocyanate.

[0011] The second aspect of the present invention provides the use of the above-mentioned polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material in the preparation of wear-resistant coated fertilizers.

[0012] The third aspect of the present invention provides a wear-resistant coated fertilizer, comprising fertilizer particles, an inner coating layer and an outer coating layer, wherein the material of the inner coating layer is polyolefin wax, and the material of the outer coating layer is the above-mentioned polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material.

[0013] Preferably, the wear-resistant coated fertilizer is prepared by the following method:

[0014] The fertilizer particles are heated to 50-70° C. in a coating machine, and polyolefin wax is sprayed on the surface of the fertilizer particles to form a wax base coating;

[0015] The polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material is sprayed onto the wax base coating in batches, and the input amount of the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material each time is 1-2% of the total mass of the fertilizer particles, and cured for 3-6 minutes; the above steps are repeated until the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material accounts for 3% to 4.5% of the total mass of the fertilizer particles.

[0016] Preferably, the added amount of the polyolefin wax is 4-6‰ of the mass of the fertilizer particles.

[0017] Preferably, the fertilizer particles are one or more of urea, diammonium phosphate, potassium chloride, and compound fertilizer.

[0018] Preferably, the fertilizer particles have a particle size of 2-5 mm.

[0019] Beneficial effects of the present invention:

[0020] 1. The present invention prepares a coating material by compounding castor oil-based polyol, isocyanate, polyether polyol and terminal hydroxyl dye. Castor oil is a natural trivalent hydroxy fatty acid ester, rich in hydroxyl (-OH) groups, and can be used as a polyol component in polyurethane synthesis. The long-chain fatty acids of castor oil provide flexible segments, giving the material good flexibility and impact resistance. Castor oil improves the flexibility of the coating material, enhances the impact resistance and crack resistance, and prevents the coating from being damaged during mechanical fertilization. Polyether polyol (such as polyethylene glycol PEG, polytetrahydrofuran PTMEG, polypropylene glycol PPG) contains multiple hydroxyl groups and can react with isocyanate to form a soft segment of polyurethane. Together with castor oil-based polyol, it adjusts the elastic modulus and hydrolysis resistance of the coating material and improves the weather resistance and environmental stability of the material. Isocyanate (-NCO group) is a core reactant in polyurethane synthesis, and reacts with the hydroxyl group of the polyol to form a polyurethane bond (-N H-COO-), providing hardness and mechanical strength of the coating material, forming a dense polymer network structure, and enhancing the wear resistance and chemical resistance of the material; the terminal hydroxyl dye molecule contains hydroxyl groups, which can participate in the cross-linking reaction of polyurethane and be embedded in the polymer chain. The chromophore structure of the dye molecule can also be used as a chain extender or end-capping agent, existing in the side chain, middle or end position of the main chain of polyurethane, enhancing the wear resistance and adhesion of the coating material, and at the same time giving the material specific functionality (such as color indication, ultraviolet shielding). The covalent bonding method prevents the migration of the dye and improves the stability of the material; castor oil-based polyols and polyether polyols react with isocyanates to form a soft and hard segment structure of polyurethane. The introduction of terminal hydroxyl dyes promotes cross-linking between chains, forms an interpenetrating network structure, and improves the mechanical properties and stability of the material. By adjusting the proportion of each component, the flexibility, hardness, wear resistance and functionality of the coating material can be accurately controlled to meet the high performance requirements of fertilizer coatings.

[0021] 2. The present invention sprays and coats the surface of the fertilizer particles with a layer of polyolefin wax to form a wax base coating, which has the following main functions: improving the adhesion of the coating material: the polyolefin wax forms a uniform and smooth coating on the surface of the fertilizer particles, filling the microscopic defects on the surface of the particles and providing a good base; the wax base coating improves the interface bonding force between the subsequent coating material and the fertilizer particles, preventing the coating from falling off under mechanical action; interface improvement: the polyolefin wax forms a uniform and smooth coating on the surface of the fertilizer particles, filling the microscopic defects on the surface of the particles and providing a good base; promoting adhesion: the wax base coating improves the interface bonding force between the subsequent coating material and the fertilizer particles, preventing the coating from falling off under mechanical action; enhancing wear resistance and protective effect: the polyolefin wax itself has a certain wear resistance, can provide preliminary protection for the fertilizer particles, reduce direct wear, and work together with the subsequent coating material to further improve the overall wear resistance of the coated fertilizer.

[0022] 3. The present invention adopts a one-step method to prepare the target polyurethane. The one-step method refers to a method in which castor oil-based polyol, isocyanate, polyether polyol and terminal hydroxyl dye are added to the reaction system at one time at the initial stage of the reaction for reaction. It has the advantages of simple process and convenient operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : Nitrogen release days of the wear-resistant coated fertilizers prepared in Examples 1-5 before and after wear;

[0024] Figure 2 : The ratio of the nitrogen release days after wear of the wear-resistant coated fertilizers prepared in Examples 1-5 to the nitrogen release days before wear;

[0025] Figure 3 : Nitrogen release days of the wear-resistant coated fertilizers prepared in Comparative Examples 1-3 before and after wear. DETAILED DESCRIPTION

[0026] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0027] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0028] The test materials used in the examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels.

[0029] The 1-amino-4-hydroxy-2-(6-hydroxyhexyloxy) anthraquinone (AHHA) used in the present invention was purchased from Hong Kong Fino Dye Chemical Company.

[0030] The polyolefin wax used in the present invention is purchased from Sinopharm Chemical Reagent Co., Ltd.

[0031] The castor oil-based polyol used in the present invention was purchased from Shandong Deken Smart Fertilizer Technology Co., Ltd.

[0032] The polyaryl polyisocyanate (PAPI, 31 wt % NCO group) used in the present invention was purchased from Yantai Wanhua Polyurethane Co., Ltd.

[0033] Example 1: Preparation of wear-resistant coated fertilizer:

[0034] (1) Add 2-5mm urea granules (1kg) into a drum and preheat to 60±2℃.

[0035] (2) 5 g of polyolefin wax as a surface modifier was uniformly coated on the surface of urea particles and mixed for 10 min to form a wax primer layer;

[0036] (3) Then, the castor oil-based polyol and the isocyanate are mixed uniformly at a mass ratio of 1.3:1 to obtain a base membrane material, polyethylene glycol and 1-amino-4-hydroxy-2-(6-hydroxyhexyloxy) anthraquinone (AHHA) are added to the base membrane material, the amount of polyethylene glycol added is 10% of the mass of the base membrane material, and the amount of AHHA added is 10% of the mass of the base membrane material, to obtain a polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material;

[0037] (4) Weigh 1% of the weight of the fertilizer core and spray the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material onto the preheated urea particles and cure for 5 minutes; repeat 3 times until the target coating amount is reached, cure into a film, form a polyurethane film layer, and obtain a wear-resistant coated fertilizer.

[0038] Example 2: Preparation of wear-resistant coated fertilizer:

[0039] (1) Add 2-5mm urea granules (1kg) into a drum and preheat to 60±2℃.

[0040] (2) 5 g of polyolefin wax as a surface modifier was uniformly coated on the surface of urea particles and mixed for 10 min to form a wax primer layer;

[0041] (3) Then, the castor oil-based polyol and the isocyanate are mixed uniformly at a mass ratio of 1.3:1 to obtain a base membrane material, polyethylene glycol and 1-amino-4-hydroxy-2-(6-hydroxyhexyloxy) anthraquinone (AHHA) are added to the base membrane material, the amount of polyethylene glycol added is 10% of the base membrane material, and the amount of AHHA added is 5% of the base membrane material, to obtain a polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material;

[0042] (4) Weigh 1% of the weight of the fertilizer core and spray the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material onto the preheated urea particles and cure for 5 minutes; repeat 3 times until the target coating amount is reached, cure into a film, form a polyurethane film layer, and obtain a wear-resistant coated fertilizer.

[0043] Example 3: Preparation of wear-resistant coated fertilizer:

[0044] (1) Add 2-5mm urea granules (1kg) into a drum and preheat to 60±2℃.

[0045] (2) 5 g of polyolefin wax as a surface modifier was uniformly coated on the surface of urea particles and mixed for 10 min to form a wax primer layer;

[0046] (3) Then, the castor oil-based polyol and the isocyanate are mixed uniformly at a mass ratio of 1.3:1 to obtain a base membrane material, polyethylene glycol and 1-amino-4-hydroxy-2-(6-hydroxyhexyloxy) anthraquinone (AHHA) are added to the base membrane material, the amount of polyethylene glycol added is 10% of the base membrane material, and the amount of AHHA added is 15% of the base membrane material, to obtain a polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material;

[0047] (4) Weigh 1% of the weight of the fertilizer core and spray the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material onto the preheated urea particles and cure for 5 minutes; repeat 3 times until the target coating amount is reached, cure into a film, form a polyurethane film layer, and obtain a wear-resistant coated fertilizer.

[0048] Example 4: Preparation of wear-resistant coated fertilizer:

[0049] (1) Add 2-5mm urea granules (1kg) into a drum and preheat to 60±2℃.

[0050] (2) 5 g of polyolefin wax as a surface modifier was uniformly coated on the surface of urea particles and mixed for 10 min to form a wax primer layer;

[0051] (3) Then, the castor oil-based polyol and the isocyanate are mixed uniformly at a mass ratio of 1.3:1 to obtain a base membrane material, polyethylene glycol and 1-amino-4-hydroxy-2-(6-hydroxyhexyloxy) anthraquinone (AHHA) are added to the base membrane material, the amount of polyethylene glycol added is 15% of the base membrane material, and the amount of AHHA added is 10% of the base membrane material, to obtain a polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material;

[0052] (4) Weigh 1% of the weight of the fertilizer core and spray the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material onto the preheated urea particles and cure for 5 minutes; repeat 3 times until the target coating amount is reached, cure into a film, form a polyurethane film layer, and obtain a wear-resistant coated fertilizer.

[0053] Example 5: Preparation of wear-resistant coated fertilizer:

[0054] (1) Add 2-5mm urea granules (1kg) into a drum and preheat to 60±2℃.

[0055] (2) 5 g of polyolefin wax as a surface modifier was uniformly coated on the surface of urea particles and mixed for 10 min to form a wax primer layer;

[0056] (3) Then, the castor oil-based polyol and the isocyanate are mixed uniformly at a mass ratio of 1.3:1 to obtain a base membrane material, polyethylene glycol and 1-amino-4-hydroxy-2-(6-hydroxyhexyloxy) anthraquinone (AHHA) are added to the base membrane material, the amount of polyethylene glycol added is 15% of the mass of the base membrane material, and the amount of AHHA added is 15% of the mass of the base membrane material, to obtain a polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material;

[0057] (4) Weigh 1% of the weight of the fertilizer core and spray the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material onto the preheated urea particles and cure for 5 minutes; repeat 3 times until the target coating amount is reached, cure into a film, form a polyurethane film layer, and obtain a wear-resistant coated fertilizer.

[0058] Comparative Example 1:

[0059] (1) Add 2-5mm urea granules (1kg) into a drum and preheat to 60±2℃.

[0060] (2) 5 g of polyolefin wax as a surface modifier was uniformly coated on the surface of urea particles and mixed for 10 min to form a wax primer layer;

[0061] (3) then mixing the castor oil-based polyol and the isocyanate in a mass ratio of 1.3:1 to obtain a base membrane material, and adding polyethylene glycol in an amount of 10% by mass of the base membrane material to the base membrane material to form a coating material;

[0062] (4) Weigh 1% of the weight of the fertilizer core coating material and spray it onto the preheated urea granules, and solidify for 5 minutes; repeat 3 times until the target coating amount is reached, solidify into a film, form a polyurethane film layer, and obtain a 3% coated fertilizer.

[0063] Comparative Example 2:

[0064] (1) Add 2-5mm urea granules (1kg) into a drum and preheat to 60±2℃.

[0065] (2) 5 g of polyolefin wax as a surface modifier was uniformly coated on the surface of urea particles and mixed for 10 min to form a wax primer layer;

[0066] (3) then mixing the castor oil-based polyol and the isocyanate in a mass ratio of 1.3:1 to obtain a base membrane material, and adding 10% of the mass of the base membrane material to the base membrane material to form a coating material;

[0067] (4) Weigh 1% of the weight of the fertilizer core coating material and spray it onto the preheated urea granules, and solidify for 5 minutes; repeat 3 times until the target coating amount is reached, solidify into a film, form a polyurethane film layer, and obtain a 3% coated fertilizer.

[0068] Comparative Example 3:

[0069] (1) Add 2-5mm urea granules (1kg) into a drum and preheat to 60±2℃.

[0070] (2) 5 g of polyolefin wax as a surface modifier was uniformly coated on the surface of urea particles and mixed for 10 min to form a wax primer layer;

[0071] (3) then mixing the castor oil-based polyol and the isocyanate in a mass ratio of 1.3:1 to form a coating material;

[0072] (4) Weigh 1% of the weight of the fertilizer core coating material and spray it onto the preheated urea granules, and solidify for 5 minutes; repeat 3 times until the target coating amount is reached, solidify into a film, form a polyurethane film layer, and obtain a 3% coated fertilizer.

[0073] Test example:

[0074] 1. Test method:

[0075] 1.1 Controlled release fertilizer release rate detection:

[0076] The nitrogen release rate of the coated fertilizers prepared in Examples 1-5 and Comparative Examples 1-3 before abrasion was measured according to the international standard ISO 18644-2016:

[0077] Weigh 10.00g of coated controlled-release fertilizer sample, place it in a glass container filled with 200.0mL of distilled water, seal it, and place it in a constant temperature incubator at 25°C. Take out the extract in the container at 1, 3, 5, 7, 14, 28, 42, 56 and 70 days, measure the nitrogen content therein, add 200.0ml of distilled water again, continue soaking and measuring, until the nitrogen release rate of the fertilizer reaches 80%.

[0078] 1.2 Controlled-release fertilizer wear treatment: Weigh 50g of different coated fertilizers, put them into a drum with a rotation speed of 3r / min and grind them with 60-mesh sandpaper for 3min, take out the worn fertilizers, and then perform the controlled-release fertilizer release rate test again according to the method in step 1, and measure the nitrogen release rate of the coated fertilizers prepared in Examples 1-5 and Comparative Examples 1-3 after wear.

[0079] 2. Test results:

[0080] Depend on Figure 1 It can be seen that the coated fertilizer prepared in Example 1 is prepared by adding 10% polyethylene glycol and 10% AHHA to the basic film material (castor oil-based polyol and isocyanate). The cumulative release days in 25-degree static water reach a maximum of 91 days, and the release days after wear are the highest, which is 83 days. The release days after wear / before wear ratio is 0.912, which is closest to 1, indicating that the fertilizer release is least affected by wear at this time, and the film material has the highest wear resistance; the release days after wear / before wear ratios of the coated fertilizers prepared in Examples 2-5 are also greater than 0.88, indicating that the wear-resistant film material prepared by the method of the present invention can effectively improve the wear resistance of the fertilizer;

[0081] In comparison example 1, only 10% polyethylene glycol was added to the base membrane material, and the ratio of release days after wear / before wear was 0.506; in comparison example 2, only 10% AHHA was added to the base membrane material, and the ratio of release days after wear / before wear was 0.351; in comparison example 3, only the base membrane material was used for coating to prepare coated fertilizer, and the ratio of release days after wear / before wear was 0.156, indicating that the addition of polyethylene glycol and terminal hydroxyl dye AHHA has a synergistic effect in improving the wear resistance of the membrane material.

[0082] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A polyether-modified hydroxyl-terminated vegetable oil polyol coating material, characterized in that: The invention is prepared from a basic membrane material, polyether polyol and terminal hydroxyl dye, wherein the basic membrane material is composed of castor oil-based polyol and isocyanate in a mass ratio of (1-2):1; The polyether polyol accounts for 10-15% of the base film material, and the terminal hydroxyl dye accounts for 5-15% of the base film material.

2. The polyether-modified hydroxyl-terminated vegetable oil polyol coating material according to claim 1, characterized in that: The terminal hydroxyl dye is 1-amino-4-hydroxy-2-(6-hydroxyhexyloxy) anthraquinone.

3. The polyether-modified hydroxyl-terminated vegetable oil polyol coating material according to claim 1, characterized in that: The polyether polyol is one or more of polyethylene glycol, polytetrahydrofuran and polypropylene glycol.

4. The polyether-modified hydroxyl-terminated vegetable oil polyol coating material according to claim 1, characterized in that: The isocyanate is a polyaryl polyisocyanate.

5. Use of the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material according to any one of claims 1 to 4 in the preparation of wear-resistant coated fertilizers.

6. A wear-resistant coated fertilizer, characterized in that: The fertilizer comprises fertilizer particles, an inner coating layer and an outer coating layer, wherein the material of the inner coating layer is polyolefin wax, and the material of the outer coating layer is the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material according to any one of claims 1 to 4.

7. The wear-resistant coated fertilizer according to claim 6, characterized in that: The wear-resistant coated fertilizer is prepared by the following method: The fertilizer particles are heated to 50-70° C. in a coating machine, and polyolefin wax is sprayed on the surface of the fertilizer particles to form a wax base coating; The polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material according to any one of claims 1 to 4 is sprayed onto the wax base coating in batches, with the input amount of the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material each time being 1 to 2% of the total mass of the fertilizer particles, and cured for 3 to 6 minutes; the above steps are repeated until the polyether-modified terminal hydroxyl-dyed vegetable oil polyol coating material accounts for 3% to 4.5% of the total mass of the fertilizer particles.

8. The wear-resistant coated fertilizer according to claim 7, characterized in that: The added amount of the polyolefin wax is 4-6‰ of the mass of the fertilizer particles.

9. The wear-resistant coated fertilizer according to claim 7, characterized in that: The fertilizer particles are one or more of urea, diammonium phosphate, potassium chloride, and compound fertilizer, and the particle size of the fertilizer particles is 2-5 mm.

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