An anti-caking agent for granular water-soluble fertilizer and its preparation method

Abstract

The present invention relates to an anti-caking agent for granular water-soluble fertilizers and a preparation method thereof. The anti-caking agent is composed of 75% - 89% polyester polyol, 1% - 5% stearamidopropyl dimethylamine (S-18), 5% - 10% ethylene glycol monostearate (EGSM), and 5% - 10% alkylphenol ether phosphate (TXP-4). The preparation method is as follows: First, add polyester polyol and stearamidopropyl dimethylamine into a reaction kettle, heat up to 80 - 100 °C, stir and keep warm until the ammonia value of the reactants is measured to be 0, and all form a new uniform substance. Then, add alkylphenol ether phosphate and ethylene glycol monostearate respectively, and stir until all substances are uniformly dispersed to obtain the anti-caking agent for water-soluble fertilizers. When the product is used, the anti-caking agent is applied at a dosage of 1.0 - 3.0 kg per ton of fertilizer, and is uniformly coated on the surface of granular water-soluble fertilizers by steam spraying. This anti-caking agent is a special anti-caking agent for granular water-soluble fertilizers.

Description

Technical Field

[0001] The present invention relates to the technical field of fertilizer anti-caking treatment, and particularly relates to an anti-caking agent for granular water-soluble fertilizers and a preparation method thereof. Background Art

[0002] 1. General Situation of Water-soluble Fertilizers

[0003] Water-soluble fertilizers are a new type of fertilizers mainly applied to facility agriculture such as drip irrigation and sprinkler irrigation to achieve the integration of water and fertilizer, and to achieve the effects of water saving, fertilizer saving and labor saving. Compared with ordinary fertilizers, its biggest feature is that it has less water-insoluble substances and less residues floating on the water surface, so it can be used for drip irrigation. Ordinary fertilizers are extremely easy to block the drip irrigation ports when used for drip irrigation, making it difficult to continuously irrigate, so they cannot be applied.

[0004] The application method of water-soluble fertilizers is very simple. It can be fertilized when irrigating with irrigation water including sprinkler irrigation, drip irrigation and other methods, which not only saves water, but also saves fertilizers and labor. With the increasing labor cost, the benefits of using water-soluble fertilizers are obvious. At home and abroad, it is widely used for irrigation fertilization of vegetables and flowers in greenhouses, various fruit trees, field crops, maintenance of landscape greening plants, golf courses, and even maintenance of household greening plants. In some large-scale planting farms, after installing modern irrigation equipment such as drip irrigation and sprinkler irrigation facilities, to achieve the integration of water and fertilizer, it is necessary to apply water-soluble fertilizers. Therefore, although water-soluble fertilizers are expensive, as a future development direction of fertilizers, they have been developing rapidly in recent years.

[0005] At present, there are mainly two forms of fully water-soluble fertilizers in China, one is powder form and the other is granular form. Once water-soluble fertilizers were mainly in powder form, and the production devices were mostly simple blending, so the output was very small and they were not mainstream fertilizers. The development of anti-caking agents for powder water-soluble fertilizers was not very necessary. However, in recent years, some large fertilizer production enterprises have gradually used the high tower process to successfully produce granular fully water-soluble fertilizers, which are used as high-end products in the market, and the output has started to increase sharply. Currently, most large fertilizer enterprises in the market have started to produce granular fully water-soluble fertilizers, thus deriving a huge market space for anti-caking agents for granular water-soluble fertilizers.

[0006] 2. General Situation of Anti-caking Agents for Water-soluble Fertilizers

[0007] Fertilizer anti-caking agent is an auxiliary agent to keep fertilizers having good fluidity during operations such as storage and spreading. In order to prevent the finished fertilizers from caking, fertilizer manufacturers generally reduce the self-caking tendency of fertilizers by improving process conditions and controlling particle characteristics, etc. At the same time, they also need to carry out coating treatment on the surface of fertilizers to form a diaphragm on the surface of fertilizer particles, reduce the migration of moisture, so as to maximize the inhibition of fertilizer caking, moisture absorption and pulverization phenomena, thereby maintaining the fluidity of particles, facilitating the storage, transportation and use of fertilizers. Therefore, as a low-cost and high-yield anti-caking measure, anti-caking agents have now been widely accepted and used by fertilizer manufacturers all over the world. There are many types of fertilizer anti-caking agents on the market at present, and the vast majority are oily anti-caking agents. Oily anti-caking agents mostly form a hydrophobic protective film on the surface of fertilizers through external wrapping. Mineral oil, due to its stable performance and good hydrophobicity, is the most widely used anti-caking agent base material at present.

[0008] However, since all the components of granular water-soluble fertilizers are soluble salts, they are very easy to absorb moisture and form crystals, and are extremely easy to agglomerate into lumps, which is very unfavorable for anti-caking. The most crucial point is that due to the very high requirements of fertilizers for the water solubility and insolubles of anti-caking agent products, traditional oily anti-caking agents cannot be applied to water-soluble fertilizers. Therefore, the anti-caking theory of using hydrophobic products to isolate fertilizers and moisture, hinder the formation of crystals by fertilizers absorbing moisture, and change the crystal structure cannot be applied to such fertilizers either.

[0009] To make the water-soluble fertilizers wrapped with anti-caking agents meet the drip irrigation requirements, the anti-caking agents used need to either be soluble in water or not form floating substances on the water surface and then aggregate to finally block the drip irrigation orifice. Therefore, for the new anti-caking requirements of granular water-soluble fertilizers, it is necessary to innovate the anti-caking theory, abandon traditional oil-based anti-caking agents, and re-look for raw materials and surfactants that can meet the drip irrigation requirements and anti-caking requirements.

[0010] At present, some manufacturers have developed anti-caking agents for granular water-soluble fertilizers. The base materials used mainly include water, high-molecular water-based materials, glycerol, short-chain alcohols and other water-soluble raw materials. However, since these anti-caking agents can neither hinder the formation of crystal bridges, nor interfere with the crystal morphology, nor have hydrophobicity to reduce the hygroscopicity of fertilizers, the anti-caking effect cannot meet the customer requirements at all. Summary of the Invention

[0011] The object of the present invention is to provide an anti-caking agent for granular water-soluble fertilizers and its preparation method in view of the drip irrigation requirements of granular water-soluble fertilizers, which thus derive unique requirements for anti-caking agents, as well as the problems existing in the above-mentioned prior art. The present invention mainly uses a high-molecular material having good fluidity at normal temperature as a carrier, and then compound a surfactant that can be well miscible with the high-molecular material and has a good anti-caking effect to ensure the anti-caking effect.

[0012] The present invention utilizes two major characteristics of polymer materials: having a density greater than that of water and being insoluble in water. Since the anti-caking agent based on this polymer material has a density greater than that of water, after the granular water-soluble fertilizer wrapped with this anti-caking agent is dissolved in water, the anti-caking agent will sink to the bottom and will not float on the water surface and aggregate to finally block the drip irrigation orifice. At the same time, after the anti-caking agent is evenly wrapped on the granular water-soluble fertilizer, the amount of the anti-caking agent wrapped on the surface of each fertilizer is extremely fine. After the granular water-soluble fertilizer wrapped with this anti-caking agent is dissolved in water, the anti-caking agent wrapped on the surface of each fertilizer will be dispersed into ultrafine powder in water and will not aggregate into sediment at the bottom to block the drip irrigation orifice.

[0013] However, precisely because this polymer material has the characteristics of having a density greater than that of water and being insoluble in water, traditional surfactants with anti-caking effects are not suitable for compounding with this material, such as fatty amines, fatty acids, phosphate esters, etc. It is necessary to re-find surfactants that not only have anti-caking effects but also can be well miscible with this polymer material and do not form layers.

[0014] A preparation method of an anti-caking agent for granular water-soluble fertilizers according to the present invention uses a polymer material - polyester polyol as the base material, uses stearamide propyl dimethylamine (S-18) to neutralize the acid value of this polymer material at high temperature to form a new anti-caking agent base material, and then compoundly uses ethylene glycol monostearate (EGSM) as a surfactant to enhance the anti-caking effect. At the same time, in order to enable the surfactant to be well miscible with the new base material, alkylphenol ether phosphate (TXP-4) is used as a solubilizer. The prepared anti-caking agent not only has hydrophobicity, but also has a density greater than that of water, and also well miscible with a surfactant that can change the crystal form. Therefore, a uniform liquid film can be formed on the surface of the fertilizer particles and can be permanently fixed on the surface of the fertilizer, making the fertilizer remain loose for a long time and have good fluidity, thereby ensuring the quality of the fertilizer. At the same time, since the density of this anti-caking agent is greater than that of water, after the water-soluble fertilizer wrapped with the anti-caking agent is dissolved in water, there will be no problem of oil film floating that occurs in currently used oily anti-caking agents, nor will it block the nozzle of the drip irrigation of the water-soluble fertilizer, so it does not affect the use of the water-soluble fertilizer. Therefore, this anti-caking agent can be used as a special anti-caking agent for granular water-soluble fertilizers.

[0015] The technical solution of the present invention is as follows:

[0016] An anti-caking agent for granular water-soluble fertilizers, calculated by mass percentage of each component, is characterized in that: the anti-caking agent is composed of 75%-89% polyester polyol, 1%-5% stearamide propyl dimethylamine (S-18), 5%-10% ethylene glycol monostearate (EGSM), and 5%-10% alkylphenol ether phosphate (TXP-4), and the sum of each component is 100%.

[0017] The polyester polyol is an amber liquid at room temperature, with a molecular weight of 1000 - 3000, an acid value of 10 - 30 mgKOH / g, a hydroxyl value of 100 - 200 mgKOH / g, and a density of 1.05 - 1.15 g / cm at room temperature 3 .

[0018] The stearamide propyl dimethylamine is a white to light yellow flaky solid at room temperature, with a content of over 99%, and an amine value of 140 - 165 mgKOH / g

[0019] The ethylene glycol monostearate is a light yellow waxy flake at room temperature, with a content of over 99%, a monoester content of over 80%, a diester content of less than 20%, and an acid value of <5 mgKOH / g

[0020] The alkylphenol ether phosphate is a colorless or slightly yellow transparent liquid at room temperature, with a solid content of over 95%, a pH value of <3.0 for a 2% aqueous solution, a monoester content of over 80%, and a diester content of less than 20%

[0021] A preparation method of an anti - caking agent for granular water - soluble fertilizer, characterized by comprising the following main steps

[0022] (1) Stir and keep the polyester polyol and stearamide propyl dimethylamine at 80 - 100 °C until the ammonia value of the reactants reaches 0

[0023] (2) Add the alkylphenol ether phosphate and ethylene glycol monostearate respectively at 80 - 100 °C, and stir until all substances are evenly dispersed to obtain the anti - caking agent for water - soluble fertilizer

[0024] An application of an anti - caking agent for granular water - soluble fertilizer, characterized in that the anti - caking agent is uniformly coated on the surface of the granular water - soluble fertilizer by steam spraying at a dosage of 1.0 - 3.0 kg per ton of fertilizer

[0025] The anti - caking agent of the present invention utilizes the characteristics of the polymer material - polyester polyol, which is insoluble in water and heavier than water, to solve the problem that the existing oily raw materials will float and aggregate on the surface and block the drip irrigation port, and also solves the problem that the existing water - soluble raw materials do not have hydrophobicity and have poor anti - caking effect, so that it has hydrophobicity to ensure the anti - caking effect and does not affect the actual use of the water - soluble fertilizer

[0026] The surfactant used in the anti - caking agent of the present invention can interfere with the crystal morphology, hinder the formation of crystal bridges, and at the same time inhibit the moisture absorption of the fertilizer, so that it has an anti - caking effect similar to that of traditional oily anti - caking agents, far superior to the water - soluble anti - caking agents based on water - soluble materials on the current market

[0027] The polyester polyol used in the present invention is a degradable material, and its green environmental protection performance is greatly improved compared with the petroleum hydrocarbon raw materials used in traditional oily anti-caking agents. At the same time, the price of this raw material has a huge advantage compared with water-soluble materials such as polyethylene glycol and glycerol, making the cost of the anti-caking agent close to the cost of the traditional oily anti-caking agent currently in use, which is more conducive to market promotion. Detailed implementation mode

[0028] The present invention will be further described in conjunction with embodiments. All raw materials used in the present invention are directly purchased. Among them, the polyester polyol used in the embodiments of the present invention is purchased from Wanhua Chemical, stearamidopropyl dimethylamine (S-18) is purchased from Solvay, ethylene glycol monostearate (EGSM) and alkylphenol ether phosphate (TXP-4) are purchased from Hai'an Petrochemical.

[0029] The heating used is electric heating; the reaction kettle is an enamel Mawes reaction kettle.

[0030] In the following embodiments, each component is calculated by mass percentage.

[0031] Embodiment 1

[0032] A. Add 75% of the polyester polyol with a molecular weight of 2000, an acid value of 20 mgKOH / g, a hydroxyl value of 150 mgKOH / g, and a density of 1.10 g / cm at room temperature 3 to the reaction kettle, start stirring and raise the temperature, and maintain the material temperature at 90 °C.

[0033] B. Add 5% of stearamidopropyl dimethylamine to the reaction kettle, mix it evenly with the polyester polyol, stir and keep warm at 90 °C for 5 h, and measure the ammonia value of the reactant to be 0;

[0034] C. Add 10% of ethylene glycol monostearate (EGSM) and 10% of alkylphenol ether phosphate (TXP-4) to the reaction kettle and mix them evenly, stir and keep warm at 90 °C for 1 h until all substances are evenly dispersed to obtain a water-soluble fertilizer anti-caking agent.

[0035] The water-soluble fertilizer anti-caking agent product (anti-caking agent 1) in Embodiment 1 is respectively coated on the granular water-soluble fertilizer - urea-sulfur-based high tower compound fertilizer 15-6-23, and the addition amount is 2.0 kg / ton for the anti-caking experiment, that is, the wrapped fertilizers are respectively subjected to a pressing cylinder test, the initial pressure is 170 N, and then placed in a constant temperature and humidity box at 45 °C and 50% RH. After storing for 24 hours, take them out and measure the experimental data of their crushing pressure as shown in Table 1:

[0036] Table 1

[0037]

[0038] Note: The smaller the crushing pressure value, the better the anti-caking effect. Conversely, the larger the crushing pressure value, the worse the anti-caking effect.

[0039] Calculation formula for the anti-caking looseness rate of fertilizers: Anti-caking looseness rate of fertilizers % = (Crushing pressure of blank fertilizer - Crushing pressure of coated fertilizer) / Crushing pressure of blank fertilizer * 100%.

[0040] Example 2

[0041] A. Add 89% of the polyester polyol with a molecular weight of 1000, an acid value of 30 mg KOH / g, a hydroxyl value of 200 mg KOH / g, and a density of 1.05 g / cm 3 at room temperature to the reaction kettle, start stirring and heat up, and maintain the material temperature at 80 °C.

[0042] B. Add 1% of stearamidopropyl dimethylamine to the reaction kettle, mix it evenly with the polyester polyol, stir and keep warm at 80 °C for 4 h, and measure the ammonia value of the reactant to be 0;

[0043] C. Add 5% of ethylene glycol monostearate (EGSM) and 5% of alkylphenol ether phosphate (TXP-4) to the reaction kettle and mix them evenly, stir and keep warm at 80 °C for 1 h until all substances are evenly dispersed to obtain a water-soluble fertilizer anti-caking agent.

[0044] Wrap the water-soluble fertilizer anti-caking agent product (anti-caking agent 4) in Example 2, the existing water-soluble anti-caking agent 2 (each component is calculated by mass percentage: 25% naphthalene sulfonic acid formaldehyde condensate, 75% water) and water-soluble anti-caking agent 3 (each component is calculated by mass percentage: 25% fatty alcohol polyoxyethylene ether, 75% polyethylene glycol) on the granular water-soluble fertilizer - nitrosulfur-based high tower compound fertilizer 15-5-25 respectively, with an addition amount of 2.0 kg / ton, and conduct an anti-caking experiment, that is, conduct a cylinder pressing test on the wrapped fertilizers respectively, with an initial pressure of 150 N, then place them in a constant temperature and humidity box at 40 °C and 50% RH, take them out after storing for 24 hours, and measure the experimental data of their crushing pressure as shown in Table 2:

[0045] Table 2

[0046]

[0047] Note: The smaller the crushing pressure value, the better the anti-caking effect. Conversely, the larger the crushing pressure value, the worse the anti-caking effect.

[0048] Calculation formula for the anti-caking looseness rate of fertilizers: Anti-caking looseness rate of fertilizers % = (Breaking pressure of blank fertilizer - Breaking pressure of coated fertilizer) / Breaking pressure of blank fertilizer * 100%.

[0049] Example 3

[0050] A. Add 80% of the polyester polyol with a molecular weight of 3000, acid value of 10 mg KOH / g, hydroxyl value of 100 mg KOH / g, and density of 1.15 g / cm³ at room temperature into the reaction kettle, start stirring and raise the temperature, and maintain the material temperature at 100 °C. 3 Start stirring and raise the temperature, and maintain the material temperature at 100 °C.

[0051] B. Add 4% of stearamidopropyl dimethylamine into the reaction kettle, mix it evenly with the polyester polyol, stir and keep warm at 100 °C for 6 h, and measure the ammonia value of the reactant to be 0;

[0052] C. Add 8% of ethylene glycol monostearate (EGSM) and 8% of alkylphenol ether phosphate (TXP-4) into the reaction kettle and mix them evenly, stir and keep warm at 100 °C for 2 h until all substances are evenly dispersed to obtain an anti-caking agent for water-soluble fertilizers.

[0053] Wrap the anti-caking agent product (anti-caking agent 5) in Example 3 on granular nitro high tower compound fertilizer 15-15-15 respectively with the existing water-soluble anti-caking agent 2 (each component is calculated by mass percentage: 25% naphthalene sulfonic acid formaldehyde condensate, 75% water) and water-soluble anti-caking agent 3 (each component is calculated by mass percentage: 25% fatty alcohol polyoxyethylene ether, 75% polyethylene glycol), with an addition amount of 2.0 kg / ton, and conduct an anti-caking experiment, that is, conduct a cylinder pressing test on the wrapped fertilizers respectively. The initial pressure is 160 N, then place them in a constant temperature and humidity box at 45 °C and 45% RH, take them out after storing for 24 hours, and measure the experimental data of their breaking pressure as shown in Table 3:

[0054] Table 3

[0055]

[0056] Note: The smaller the breaking pressure value, the better the anti-caking effect. On the contrary, the larger the breaking pressure value, the worse the anti-caking effect.

[0057] Calculation formula for the anti-caking looseness rate of fertilizers: Anti-caking looseness rate of fertilizers % = (Breaking pressure of blank fertilizer - Breaking pressure of coated fertilizer) / Breaking pressure of blank fertilizer * 100%.

[0058] Example 4

[0059] A. Add 87% of the polyester polyol with a molecular weight of 1200, acid value of 15 mg KOH / g, hydroxyl value of 120 mg KOH / g, and density of 1.10 g / cm³ at room temperature into the reaction kettle, start stirring and raise the temperature, and maintain the material temperature at 100 °C.3 The polyester polyol was added to the reaction kettle, the stirring was started and the temperature was raised, and the temperature of the material was maintained at 95 °C;

[0060] B. 3% of stearamidopropyldimethylamine was added to the reaction kettle, uniformly mixed with the polyester polyol, stirred and kept warm at 95 °C for 5 h, and the amine value of the reactant was measured to be 0;

[0061] C. 5% of ethylene glycol monostearate (EGSM) and 5% of alkylphenol ether phosphate (TXP-4) were added to the reaction kettle and uniformly mixed, stirred and kept warm at 95 °C for 1.5 h until all substances were uniformly dispersed to obtain an anti-caking agent for water-soluble fertilizer.

[0062] The anti-caking agent product (anti-caking agent 6) in Example 4 was coated on the granular nitro high tower compound fertilizer 15-5-25, respectively, with the existing water-soluble anti-caking agent 2 (each component is calculated by mass percentage: 25% naphthalene sulfonic acid formaldehyde condensate, 75% water) and water-soluble anti-caking agent 3 (each component is calculated by mass percentage: 25% fatty alcohol polyoxyethylene ether, 75% polyethylene glycol) mentioned in this patent. The addition amount was 2.0 kg / ton for the anti-caking experiment, that is, the wrapped fertilizers were respectively subjected to a cylinder pressing test, the initial pressure was 160 N, and then placed in a constant temperature and humidity box at 40 °C and 50% RH. After storing for 24 hours, they were taken out, and the experimental data of the crushing pressure were measured as shown in Table 4:

[0063] Table 4

[0064]

[0065] Note: The smaller the crushing pressure value, the better the anti-caking effect. On the contrary, the larger the crushing pressure value, the worse the anti-caking effect.

[0066] The calculation formula for the anti-caking loose rate of fertilizer: anti-caking loose rate of fertilizer % = (crushing pressure of blank fertilizer - crushing pressure of wrapped fertilizer) / crushing pressure of blank fertilizer * 100%.

Claims

1. A kind of anti-caking agent for granular water-soluble fertilizer, calculated by mass percentage of each component, it is characterized in that: The anti-caking agent is composed of 75%-89% polyester polyol, 1%-5% stearamidopropyl dimethylamine (S-18), 5%-10% ethylene glycol monostearate (EGSM), and 5%-10% alkylphenol ether phosphate (TXP-4), and the sum of each component is 100%; the polyester polyol is an amber liquid at room temperature, with a molecular weight of 1000-3000, an acid value of 10-30 mgKOH / g, a hydroxyl value of 100-200 mgKOH / g, and a density of 1.05-1.15 g / cm at room temperature 3 .

2. The anti-caking agent for granular water-soluble fertilizer described in claim 1, it is characterized in that : The stearamide propyl dimethylamine is a white to light yellow flaky solid at room temperature, and its content is more than 99%.

3. The anti-caking agent for granular water-soluble fertilizer described in claim 1, it is characterized in that : The ethylene glycol monostearate is a light yellow waxy flake at room temperature, the content of the monoester accounts for more than 80%, and the content of the diester accounts for less than 20%.

4. The anti-caking agent for granular water-soluble fertilizer described in claim 1, it is characterized in that : The alkylphenol ether phosphate is a colorless or slightly yellow transparent liquid at room temperature, the solid content is more than 95%, the pH value is <3.0, the content of the monoester accounts for more than 80%, and the content of the diester accounts for less than 20%.

5. The preparation method of the anti-caking agent for granular water-soluble fertilizer as described in any one of claims 1-4, it is characterized in that, including the following main steps: (1) Polyester polyol and stearamide propyl dimethylamine are stirred and kept warm at 80-100 °C until the ammonia value of the reactant is measured to be 0; (2) Alkylphenol ether phosphate and ethylene glycol monostearate are added respectively at 80-100 °C, and stirred until all substances are evenly dispersed to obtain the anti-caking agent for water-soluble fertilizer.

6. The application of the anti-caking agent for granular water-soluble fertilizer as described in any one of claims 1-4, it is characterized in that, The anti-caking agent is applied at a dosage of 1.0-3.0 kg / ton of fertilizer, and is evenly coated on the surface of the granular water-soluble fertilizer by steam spraying.

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