Anti-blocking agent as well as preparation method and application thereof

Abstract

The invention discloses an anti-blocking agent and a preparation method and application thereof, and belongs to the technical field of chemical fertilizer assistants, and the anti-blocking agent comprises at least one of a surfactant capable of controlling the length of hydrophilic and hydrophobic chain segments, a macromolecular surfactant and inert powder. Wherein the surfactant capable of controlling the length of the hydrophilic and hydrophobic chain segment comprises at least one of fatty alcohol-polyoxyethylene ether, fatty acid methyl ester polyoxyethylene ether, fatty amine polyoxyethylene ether, fatty acid amide and fatty glyceride. The anti-blocking agent is prepared in a blending mode, the anti-blocking agent is directly put into the liquid raw materials of the fertilizer to be evenly mixed, through the spray drying technology, moisture is completely evaporated, main components of the anti-blocking agent are firmly attached to the surfaces of powder fertilizer particles, the raw materials are easy to obtain, preparation is convenient, and the anti-blocking agent has the advantages of being high in anti-blocking efficiency, convenient to use and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of fertilizer adjuvants, and particularly relates to an anti-caking agent and a preparation method and application thereof. Background Art

[0002] Fertilizer is an indispensable substance in agricultural production. It is directly related to the growth, yield and quality of crops. With the steady development of agricultural production, the requirements for fertilizers have also increased accordingly. Some water-soluble fertilizers are prone to caking when packaged, stored and transported in a hot and humid environment, which not only affects the appearance quality of the product, but also causes great inconvenience to its downstream applications. Theoretical analysis shows that after the fertilizer absorbs moisture to a higher moisture content due to the environment, the surface of the fertilizer particles begins to stick. As the temperature rises, the solubility of the fertilizer further increases. When the fertilizer dissolves to saturation, the temperature decreases or the evaporation of water vapor will cause the fertilizer or salt substances to gradually precipitate, resulting in agglomeration. In addition, when the fertilizer particle size is small or the particle size distribution is uneven, the contact area between the particles is large, and it is easier to compact after moisture absorption and pressurization. Therefore, it is necessary to develop an effective anti-caking agent to inhibit the occurrence of this problem. Currently, the commonly used fertilizer anti-caking agents mainly include inorganic salt anti-caking agents, inert powder anti-caking agents, surfactant anti-caking agents and anti-caking agents compounded with inert powders, polymers, surfactants, etc.

[0003] Chinese patent application document (CN114773121A) discloses an anti-caking agent for nitro compound fertilizer, which is mainly obtained by compounding montmorillonite, organic coupling agent and ferric oxide, and the anti-caking agent is evenly coated on the surface of compound fertilizer by additional operation such as spraying. This method forms a hydrophobic layer through the long-chain alkyl in the coupling agent structure, and competes with ferric oxide for moisture absorption, thereby achieving the purpose of preventing fertilizer particles from absorbing water. The preparation process of the anti-caking agent in this method is complicated, and the main component in the formula is water-insoluble solid particles. Long-term use will cause insoluble matter to deposit, which is not conducive to downstream drip irrigation operations. Chinese patent application document (CN104671989A) discloses an anti-caking agent for water-soluble nitro compound fertilizer, the main components of which are sodium tripolyphosphate, sodium dodecyl sulfate, polyacrylamide, etc. A powder anti-caking agent is prepared by mixing the above components, and the particle size is 300 mesh, and it is applied by blending with powder fertilizer. The method attempts to reduce the moisture absorption of powder fertilizer by long alkyl chains, and reduce the sticking effect between powder fertilizer particles by anti-caking agent powder, so as to achieve the purpose of reducing the agglomeration of powder fertilizer. For powder fertilizer with smaller particle size (within 100 μm) and stronger hygroscopicity, the anti-caking agent has poor effect. Chinese patent application document (CN116535258A) discloses an anti-caking agent for granular water-soluble fertilizer, which is mainly composed of polyether polyol, triethylene glycol and a small amount of stearate and phosphate, and is evenly coated on the surface of powder fertilizer by steam atomization. The method mainly utilizes the amphoteric property of surfactant structure, i.e., hydrophobicity and hydrophilicity. When the hydrophilic end of the surfactant interacts with the fertilizer, the hydrophobic end is arranged on the surface of the fertilizer to form a hydrophobic layer, thereby reducing the moisture absorption of the fertilizer and reducing the agglomeration rate of the fertilizer. In the patent, the anti-caking agent needs to add a spraying step after the production is completed, and the complicated use steps may increase the moisture absorption of the powder fertilizer.

[0004] CN201410631378.1 of Shaanxi Institute of Technology discloses an environmentally friendly anti-caking agent for compound fertilizer and its preparation method. The nonionic surfactant used in the patent formula is any one of polyols, octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, phenethylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether, or a mixture of any two or more thereof; wherein the polyol is one or more of Span-80, Tween-60, and Tween-85. The patent formula does not contain inert powder, and the application method is different from that of the present application. Hebei Green Nonghua Technology Co., Ltd. CN201610297913.3 discloses a silicon-containing anti-caking solid macro-element water-soluble fertilizer and its preparation method. The patent formula contains surfactants, which are divided into two types: built-in and external. The built-in surfactants include sodium lignin sulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, 2-naphthalenesulfonic acid formaldehyde polymer sodium salt, polyvinyl pyrrolidone, and fatty alcohol polyoxyethylene ether. One or more; external surfactants include dimethyl silicone oil, ethylenediamine, octadecanoic acid, polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxypropylene glycerol ether, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether. One or more, in addition, it also includes organic polymers such as polyacrylamide, silicate and sodium tripolyphosphate, and the anti-caking agent component is attached to the surface of the powder fertilizer in the form of spraying. The patent has a different formula from the present application and a different application method. Shenzhen Batian Ecological Engineering Co., Ltd. CN201710524873.6 discloses an anti-caking agent and an anti-caking fertilizer and a preparation method thereof. In addition to surfactants and hydrophobic agents (inert powders), the patent formula also includes a coagulant and a high molecular polymer. The patent has a different formula from the present application and a different application method. Beijing Yaozhilong Technology Development Co., Ltd. CN201810175017.9 discloses a special anti-caking agent for ammonium sulfate, its preparation method and application, and uses a non-ionic surfactant as one of the formula ingredients, selected from one or more of alkylphenol polyoxyethylene ether, sorbitol fatty acid ester, sorbitol fatty acid ester polyoxyethylene ether, and fatty alcohol polyoxyethylene ether; alkylphenol polyoxyethylene ether is selected from OP series emulsifiers and NP series emulsifiers; sorbitol fatty acid ester is selected from S-20, S-40, S-60, and S-80; sorbitol fatty acid ester polyoxyethylene ether is selected from Tween-20, Tween-40, Tween-60, Tween-80, and Tween-85; fatty alcohol polyoxyethylene ether is selected from AEO-5, AEO-7, and AEO-9. The patent formula does not contain inert powder, and the application method is different from the present invention.Anhui Furuixue Chemical Technology Co., Ltd. CN201910500531.X discloses a water-retaining, slow-release, anti-caking multifunctional fertilizer adjuvant, which is composed of a water-retaining, slow-release component, a surfactant component (sodium laurate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, Tween 60, Tween 80, Span 60, Span 80, stearic acid, etc.), an inert powder (talcum powder, nano-silicon dioxide or heavy calcium powder) component, and an anti-caking and synergistic component. The patent has a different formula from the present application and a different application method.

[0005] In summary, conventional inorganic salts, inert powders, and coarse particle blending methods are unlikely to prevent finer particle powder fertilizers from caking. In addition, since fertilizer production is generally non-sealed, blending, spraying, and other steps after production greatly prolong the moisture absorption time of the fertilizer, which is not conducive to maintaining the fluidity of the fertilizer particles during storage and transportation. Summary of the invention

[0006] The object of the present invention is to provide an anti-caking agent and a preparation method and application thereof, so as to solve the problem that powder fertilizer is easy to agglomerate in the prior art.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] The first aspect of the present invention provides an anti-caking agent, comprising at least one of a surfactant capable of controlling the length of hydrophilic and hydrophobic segments, a macromolecular surfactant, and an inert powder.

[0009] Furthermore, the anti-caking agent includes at least a surfactant capable of controlling the length of the hydrophilic and hydrophobic segments, and the surfactant capable of controlling the length of the hydrophilic and hydrophobic segments includes at least one of fatty alcohol polyoxyethylene ether, fatty acid methyl ester polyoxyethylene ether, fatty amine polyoxyethylene ether, fatty acid amide, and fatty acid glyceride.

[0010] Furthermore, the fatty alcohol polyoxyethylene ether, fatty acid methyl ester polyoxyethylene ether, fatty amine polyoxyethylene ether, fatty acid amide, fatty acid glyceride are liquid or paste at room temperature, wherein the number of carbon atoms in the fatty alcohol / fatty acid / fatty amine part (hydrophobic end) is 8-19, and the number of hydrophilic groups is 2-10. After mixing, one or more of them have good water solubility or can be uniformly dispersed in an aqueous solution.

[0011] Furthermore, the fatty alcohol polyoxyethylene ether includes at least one of AEO-3, AEO-5, and AEO-7; the fatty amine polyoxyethylene ether includes at least one of AC-1202, AC-1203, AC-1205, AC-1210, and AC-1810; the fatty acid amide includes at least one of oleic acid diethanolamide and coconut oil diethanolamide; the fatty acid glyceride includes at least one of hexaglycerol laurate and decaglycerol caprylate.

[0012] Furthermore, the anti-caking agent at least includes a macromolecular surfactant, which includes a surfactant with a multi-branched structure, or other surfactants with a coexisting cyclic and branched structure, or a high-molecular surfactant with a molecular weight of not less than 5000.

[0013] Furthermore, the anti-caking agent at least includes inert powder, and the inert powder includes at least one of silicon dioxide, talc, kaolin, diatomaceous earth, zinc oxide, calcium oxide, and silicate.

[0014] Furthermore, the anti-caking agent at least comprises inert powder, and the particle size of the inert powder is ≥1000 mesh.

[0015] Furthermore, the anti-caking agent at least comprises inert powder, and the particle size of the inert powder is ≥ 8000 mesh.

[0016] The second aspect of the present invention provides a method for preparing an anti-caking agent, comprising the following steps:

[0017] At least one of a surfactant capable of controlling the length of hydrophilic and hydrophobic segments, a macromolecular surfactant, and an inert powder is mixed to obtain an anti-caking agent.

[0018] The third aspect of the present invention provides use of the anti-caking agent described in the first aspect in powder fertilizer.

[0019] Furthermore, the raw material of the powder fertilizer is in a liquid state, and the solid content of the powder fertilizer raw material is ≤65%. The powder fertilizer is obtained by adjusting the pH of the stock solution, atomizing and drying, bagging and other production processes; the amount of the anti-caking agent is 0.5%-2.5% of the mass concentration of the powder fertilizer raw material; wherein the mass concentration is the solute mass of the raw material; the anti-caking agent is added to the powder fertilizer raw material by a mixing method.

[0020] Beneficial effects of the present invention:

[0021] The main component of the anti-caking agent provided by the present invention is a surfactant or a fine-grained inert powder. A hydrophobic layer is formed on the surface of the fertilizer by relying on the amphoteric structural characteristics of the surfactant, thereby reducing the moisture absorption of the fertilizer environment; the fluidity of the fertilizer particles is increased by relying on the spatial occupation of the surfactant hydrophobic carbon chain, macromolecules and the mechanical barrier effect of the inert powder; the anti-caking agent is prepared by blending, the anti-caking agent is directly added to the fertilizer liquid raw material for mixing, and the water is completely evaporated through a spray drying process, and the main components of the anti-caking agent are firmly attached to the surface of the powder fertilizer particles. The raw materials are easily available and the preparation is convenient, and the anti-caking efficiency is high, the use is convenient, and the anti-caking efficiency is high.

[0022] The anti-caking agent provided by the present invention is directly added to the raw materials when used, without complicated preparation process, does not affect the normal production steps, and is very convenient to use; after the fertilizer is produced, it is directly bagged without the need for additional steps such as blending and spraying, which greatly reduces the time the fertilizer product is exposed to the environment and effectively reduces its environmental moisture absorption;

[0023] The anti-caking agent provided by the present invention has good water solubility or dispersibility, and the fine-grained inert powder can be evenly dispersed in an aqueous solution under the action of a surfactant, without the presence of large particles and without the risk of downstream sprinkler irrigation operations clogging the nozzle.

[0024] The present invention provides a fertilizer anti-caking agent with excellent anti-caking performance from the perspective of the interaction between the surfactant and the fertilizer, the water-isolating property of the hydrophobic end, the dispersibility in water, and the barrier effect of the inert powder in the fertilizer. The anti-caking agent in the present invention is directly added to the fertilizer raw material when used, is easy to use, has no large particles of insoluble matter in the formula, and the inert powder can be evenly dispersed in water under the action of the surfactant, without affecting the production and downstream use of the fertilizer.

[0025] The present invention relies on the excellent properties of surfactants in the application of anti-caking agents, and compounds surfactants with fine-particle inert powders to achieve excellent anti-caking effects. Fatty alcohol polyoxyethylene ethers, fatty acid methyl ester polyoxyethylene ethers, fatty amine polyoxyethylene ethers, fatty acid amides, and fatty acid glycerides are selected to adjust the water solubility of the anti-caking agent; macromolecular surfactants, such as sorbitan fatty acid esters (Span), polysorbate (Tween), crown ether surfactants, multi-branched isomeric alcohol polyoxyethylene ethers, cellulose, lignin, and starch are selected to further increase the interaction between fertilizer particles; fine-particle silicon dioxide, talc, kaolin, diatomaceous earth, zinc oxide, calcium oxide, and silicates are selected for mechanical isolation. In this formula, on the one hand, the surfactant acts on the surface of the fertilizer particles to reduce the crystallization performance of the fertilizer. At the same time, the surfactant forms a hydrophobic layer on the surface of the fertilizer, which effectively reduces the moisture absorption of the fertilizer. On the other hand, fatty alcohol polyoxyethylene ether, fatty acid methyl ester polyoxyethylene ether, fatty amine polyoxyethylene ether, etc. can adjust the solubility and hydrophobicity of the anti-caking agent by controlling the length of the hydrophobic end carbon chain and the number of hydrophilic groups. Natural compounds with multi-branched structures, cyclic branched coexistence structures or large molecular weights, such as cellulose, lignin, starch, etc., have a large structural space occupation, which can effectively reduce the adhesion between fertilizer particles. In addition, mechanical barriers can be added by adding fine particles of talc, silica, kaolin, etc., which can effectively increase the fluidity of fertilizer particles.

[0026] Fertilizers can be divided into solid fertilizers, liquid fertilizers, gas fertilizers, etc. according to their form. Among them, the nutrient content of liquid fertilizers is relatively low, and long-term placement may cause problems such as nutrient precipitation. Atomizing and drying liquid fertilizers into solid powder fertilizers by a spray dryer is one of the effective solutions. The present invention mainly acts on liquid raw materials to obtain powder fertilizers through spray drying. When used, 0.5% to 5.0% of anti-caking agent is directly added to the raw material liquid, and the production is carried out according to the original process after stirring and mixing. After the production is completed, it is directly bagged without further processing. The anti-caking agent has good solubility or dispersibility in water, and its hydrophilic end is firmly combined with the solute molecule. After spray drying, the surfactant acts on the surface of the powder fertilizer, and a hydrophobic layer is formed on the outer layer of the powder fertilizer particles, which effectively reduces its environmental moisture absorption. At the same time, the hydrophobic carbon chain of the surfactant, the macromolecular surfactant or the inert powder effectively blocks the direct contact between the powder fertilizer particles, reduces the sticky effect between the powders, thereby achieving the purpose of reducing fertilizer agglomeration. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] Figure 1 It is a diagram of the caking condition of the powder fertilizer in Example 1 of the present invention;

[0029] Figure 2 It is a diagram of the caking condition of the powder fertilizer in Example 2 of the present invention;

[0030] Figure 3 It is a diagram of the caking condition of the powder fertilizer in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The preparation method of an anti-caking agent in the present invention is as follows:

[0033] At least one of a surfactant capable of controlling the length of hydrophilic and hydrophobic segments, a macromolecular surfactant, and an inert powder is mixed to obtain an anti-caking agent.

[0034] Example 1

[0035] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate was adjusted to 5.0 mL / min, 1.0 g of isomeric tridecanol polyoxyethylene ether 10 (13, 10) was weighed and put into 200 g of 50% fertilizer stock solution (added amount was 1.0%) and stirred for 0.5 h. After mixing, it was spray-dried to obtain a powder fertilizer sample with a particle size of 50 μm.

[0036] The moisture absorption per unit mass of the powder fertilizer was measured to be 4.2%, and the caking rate was 18.6%.

[0037] In the isomeric tridecanol polyoxyethylene ether 10 (13, 10), 13 represents the number of carbon atoms in the main chain of the surfactant hydrophobic end, and 10 represents the number of hydrophilic groups at the hydrophilic end, the same below.

[0038] Example 2

[0039] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate was adjusted to 5.0 mL / min, 1.0 g of isooctyl polyoxyethylene ether 4 (8,4) was weighed and added into 200 g of 50% fertilizer stock solution (addition amount was 1.0%) and stirred for 0.5 h. After mixing, it was spray-dried to obtain a powder fertilizer sample with a particle size of 50 μm.

[0040] The moisture absorption per unit mass of the powder fertilizer was measured to be 3.8%, and the caking rate was 16.2%.

[0041] Example 3

[0042] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, and the peristaltic pump rate to 5.0 mL / min. 0.5 g AC1202 (12, 2) and AEO-7 (12-16, 7) were weighed respectively, mixed evenly, and then added into 200 g of 50% fertilizer stock solution (added amount was 1.0%) and stirred for 0.5 h. After mixing, spray drying was performed to obtain a powder fertilizer sample with a particle size of 50 μm.

[0043] The moisture absorption per unit mass of the powder fertilizer was measured to be 3.4%, and the caking rate was 13.1%.

[0044] Implementation Example 4

[0045] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate was adjusted to 5.0 mL / min, 1.0 g of fatty acid methyl ester polyoxyethylene ether (19,7) was weighed and added into 200 g of 50% fertilizer stock solution (added amount was 1.0%) and stirred for 0.5 h. After mixing, it was spray-dried to obtain a powder fertilizer sample with a particle size of 50 μm.

[0046] The moisture absorption per unit mass of the powder fertilizer was measured to be 3.6%, and the caking rate was 14.3%.

[0047] Example 5

[0048] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, 1.0 g of hexaglycerol laurate (12,6) and 0.5 g of microcrystalline cellulose were weighed, mixed evenly, and then added into 200 g of 50% fertilizer stock solution (added at 1.5%) and stirred for 0.5 h. After mixing, spray drying was performed to obtain a powder fertilizer sample with a particle size of 50 μm.

[0049] The moisture absorption per unit mass of the powder fertilizer was measured to be 3.5%, and the caking rate was 13.2%.

[0050] Example 6

[0051] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate was adjusted to 5.0 mL / min, 1.0 g AEO-5 (12-16, 5) and 1.0 g silicon dioxide (8000 mesh) were weighed and put into 200 g of 50% fertilizer stock solution (added amount was 2.0%) and stirred for 0.5 h. After mixing, spray drying was performed to obtain a powder fertilizer sample with a particle size of 50 μm.

[0052] The moisture absorption per unit mass of the powder fertilizer was measured to be 3.3%, and the caking rate was 10.6%.

[0053] Example 7

[0054] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate was adjusted to 5.0 mL / min, 1.0 g AEO-5 (12-16, 5) and 1.0 g silicon dioxide (1000 mesh) were weighed and put into 200 g of 50% fertilizer stock solution (added amount was 2.0%) and stirred for 0.5 h. After mixing, spray drying was performed to obtain a powder fertilizer sample with a particle size of 50 μm.

[0055] The moisture absorption per unit mass of the powder fertilizer was measured to be 3.4%, and the caking rate was 12.8%.

[0056] Example 8

[0057] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, 0.5 g AC-1810 (18, 10), 0.5 g decaglycerol octanoate (8-10, 10), 0.5 g lignin and 0.5 g talc (8000 mesh) were weighed, mixed evenly, and then added into 200 g of 50% fertilizer stock solution (added amount was 2.0%) and stirred for 0.5 h. After mixing, spray drying was performed to obtain a powder fertilizer sample with a particle size of 50 μm.

[0058] The moisture absorption per unit mass of the powder fertilizer was measured to be 2.8%, and the caking rate was 9.6%.

[0059] Example 9

[0060] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, 0.5 g AC-1203 (12, 3), 0.5 g decaglycerol caprylate (8, 10), 0.5 g Tween 80 and 0.5 g zinc oxide (1000 mesh) were weighed, mixed and put into 200 g of 50% fertilizer stock solution (added amount was 2.0%) and stirred for 0.5 h. After mixing, spray drying was carried out to obtain a powder fertilizer sample with a particle size of 50 μm.

[0061] The moisture absorption per unit mass of the powder fertilizer was measured to be 2.5%, and the caking rate was 8.5%.

[0062] Example 10

[0063] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, 0.5 g AC-1205 (12, 5), 0.5 g decaglycerol caprate (10, 10), 0.5 g Tween 85 and 0.5 g aluminum silicate (1000 mesh) were weighed, mixed and added into 200 g of 50% fertilizer stock solution (added at 2.0%) and stirred for 0.5 h. After mixing, spray drying was performed to obtain a powder fertilizer sample with a particle size of 50 μm.

[0064] The moisture absorption per unit mass of the powder fertilizer was measured to be 2.5%, and the caking rate was 8.7%.

[0065] Embodiment 11

[0066] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, 1.0 g of coconut oil diethanolamide (12,2), 0.5 g of amylopectin and 0.5 g of kaolin (8000 mesh) were weighed, mixed and put into 200 g of 50% fertilizer stock solution (added amount was 2.0%) and stirred for 0.5 h. After mixing, spray drying was carried out to obtain a powder fertilizer sample with a particle size of 50 μm.

[0067] The moisture absorption per unit mass of the powder fertilizer was measured to be 2.3%, and the caking rate was 6.3%.

[0068] Example 12

[0069] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, 0.5 g of isomeric tridecanol polyoxyethylene ether 10 (13, 10), 0.5 g of Tween 85, 0.5 g of Span 60, 0.5 g of diatomaceous earth (8000 mesh) and 0.5 g of calcium oxide (1000 mesh) were weighed, mixed evenly, and then added into 200 g of 50% fertilizer stock solution (added amount was 2.5%) and stirred for 0.5 h. After mixing, spray drying was performed to obtain a powder fertilizer sample with a particle size of 50 μm.

[0070] The moisture absorption per unit mass of the powder fertilizer was measured to be 2.5%, and the caking rate was 4.3%.

[0071] Embodiment 13

[0072] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, 1.0 g of coconut oil diethanolamide (12, 2), 0.5 g of branched polysiloxane grafted crown ether and 0.5 g of silica (8000 mesh) were weighed, mixed evenly, and then added into 200 g of 50% fertilizer stock solution (added amount was 2.0%) and stirred for 0.5 h. After mixing, spray drying was performed to obtain a powder fertilizer sample with a particle size of 50 μm.

[0073] The moisture absorption per unit mass of the powder fertilizer was measured to be 2.1%, and the caking rate was 4.7%.

[0074] Embodiment 14

[0075] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, 0.05 g of oleic acid diethanolamide (18, 2), 0.05 g of isomeric tridecanol polyoxyethylene ether 10 (13, 10), 0.2 g of Span 80 and 0.2 g of silicon dioxide (8000 mesh) were weighed, mixed evenly, and then added into 200 g of 50% fertilizer stock solution (the addition amount was 0.5%) and stirred for 0.5 h. After mixing, spray drying was performed to obtain a powder fertilizer sample with a particle size of 50 μm.

[0076] The moisture absorption per unit mass of the powder fertilizer was measured to be 4.0%, and the caking rate was 15.8%.

[0077] Embodiment 15

[0078] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, 0.5 g of oleic acid diethanolamide, 0.5 g of isomeric tridecyl alcohol polyoxyethylene ether 10 (13, 10), 2.0 g of Span 80 and 2.0 g of silicon dioxide (8000 mesh) were weighed, mixed evenly, and then added into 200 g of 50% fertilizer stock solution (the addition amount was 5.0%) and stirred for 0.5 h. After mixing, spray drying was carried out to obtain a powder fertilizer sample with a particle size of 50 μm.

[0079] The moisture absorption per unit mass of the powder fertilizer was measured to be 2.1%, and the caking rate was 4.3%.

[0080] Example 16

[0081] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, 0.6 g of oleic acid diethanolamide, 0.6 g of isomeric tridecyl alcohol polyoxyethylene ether 10 (13, 10), 2.4 g of Span 80 and 2.4 g of silicon dioxide (8000 mesh) were weighed, mixed evenly, and then added into 200 g of 50% fertilizer stock solution (the addition amount was 6.0%) and stirred for 0.5 h. After mixing, spray drying was carried out to obtain a powder fertilizer sample with a particle size of 50 μm.

[0082] The moisture absorption per unit mass of the powder fertilizer was measured to be 2.0%, and the caking rate was 4.2%.

[0083] Comparative Example 1

[0084] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate to 5.0 mL / min, and 200 g of 50% fertilizer stock solution was spray-dried to obtain powder fertilizer with a particle size of 50 μm.

[0085] The moisture absorption per unit mass of the powder fertilizer was measured to be 6.5%, and the caking rate was 88.9%.

[0086] Comparative Example 2

[0087] Set the spray dryer fan speed to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, adjust the peristaltic pump rate to 5.0 mL / min, weigh 1.0 g of polyglycerol-4 (0,4) and put it into 200 g of 50% fertilizer stock solution (added amount is 1.0%) and stir for 0.5 h. After mixing, spray dry to obtain powder fertilizer with a particle size of 50 μm.

[0088] The moisture absorption per unit mass of the powder fertilizer was measured to be 6.8%, and the caking rate was 90.2%.

[0089] Comparative Example 3

[0090] The fan speed of the spray dryer was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate was adjusted to 5.0 mL / min, 1.3 g of Perigax O-25 (18, 35) was weighed and added into 200 g of 65% fertilizer stock solution (added amount was 1.0%) and stirred for 0.5 h. After mixing, it was spray-dried to obtain a powder fertilizer sample with a particle size of 50 μm.

[0091] The moisture absorption per unit mass of the powder fertilizer was measured to be 6.2%, and the caking rate was 82.4%.

[0092] Comparative Example 4

[0093] Set the spray dryer fan speed to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, adjust the peristaltic pump rate to 5.0 mL / min, weigh 2.0 g of silicon dioxide (800 mesh) and put it into 200 g of 50% fertilizer stock solution (added amount is 2.0%) and stir for 0.5 h. After mixing, spray dry to obtain powder fertilizer with a particle size of 50 μm.

[0094] The moisture absorption per unit mass of the powder fertilizer was measured to be 6.3%, and the caking rate was 86.1%.

[0095] Comparative Example 5

[0096] Set the spray dryer fan speed to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, adjust the peristaltic pump rate to 5.0 mL / min, weigh 0.5 g of polyglycerol-4 (0, 2) and 2.0 g of silicon dioxide (800 mesh), mix them evenly, put them into 200 g of 50% fertilizer stock solution (added amount is 2.5%) and stir for 0.5 h. After mixing, spray dry to obtain powder fertilizer with a particle size of 50 μm.

[0097] The moisture absorption per unit mass of the powder fertilizer was measured to be 6.5%, and the caking rate was 79.6%.

[0098] Comparative Example 6

[0099] The spray dryer fan speed was set to 85%, the inlet air temperature to 170°C, the spray pressure to 1.0 MPa, the peristaltic pump rate was adjusted to 5.0 mL / min, 1.34 g of isomeric tridecanol polyoxyethylene ether 10 (13, 10) was weighed, and after uniform addition, it was added into 200 g of 67% fertilizer stock solution (added amount was 1.0%) and stirred for 0.5 h. After mixing, spray drying was performed. Due to the high concentration of the solution, the atomization effect was poor and no uniform powder sample was obtained.

[0100] 1) The formula of the anti-caking agent in Examples 1 to 16 and Comparative Examples 1 to 6 is shown in Table 1:

[0101] Table 1

[0102]

[0103]

[0104]

[0105]

[0106] 2) The powder fertilizers obtained in Examples 1 to 16 and Comparative Examples 1 to 6 were tested: the moisture absorption per unit mass of the powder fertilizers after 4 hours of moisture absorption under certain conditions (30° C., 65% RH) was measured to measure their anti-hygroscopic properties, and the caking rates of the powder fertilizers with different anti-caking agents added after being placed at 50° C. for 8 days were measured by a pressure mold (20 KPa). The test results are shown in Table 2:

[0107] Table 2

[0108]

[0109]

[0110] 3) 10 g of the powder fertilizer obtained in Example 1, Example 2 and Comparative Example 1 was selected and pressed by a pressure mold for 8 days, and the lumps remaining after passing through a 30-mesh sieve were photographed for comparison:

[0111] Figure 1 This is a diagram showing the lumps remaining after the powder fertilizer obtained in Example 1 was pressed by a pressure mold for 8 days and passed through a 30-mesh screen; Figure 2 This is a diagram showing the lumps remaining after the powder fertilizer obtained in Example 2 was pressed by a pressure mold for 8 days and passed through a 30-mesh screen; Figure 3This is a diagram showing the lumps remaining after the powder fertilizer obtained in Comparative Example 1 was pressed by a pressure mold for 8 days and passed through a 30-mesh sieve.

[0112] From Table 1-2 and Figure 1-3 It can be seen that in Comparative Examples 2 and 3, 1.0% polyglycerol-4 and Pingpingjia O-25 were added to the powder fertilizer respectively, and the moisture absorption and caking rate were not significantly different from those in Comparative Example 1. It is speculated that the reason is that the carbon chain of the hydrophobic end of the surfactant is shorter or the hydrophilic group is more, and an effective hydrophobic layer is not formed on the surface of the powder fertilizer. In Comparative Example 4, adding 2.0% silicon dioxide (800 mesh) still did not have a significant anti-caking effect. It is speculated that the main reason is that the silicon dioxide particles are larger and the mechanical barrier effect is poor when doped in the powder fertilizer. In addition, since silicon dioxide is suspended on the surface of the fertilizer stock solution, the mixing uniformity is poor. In Comparative Example 5, by adding a small amount of polyglycerol-4, silicon dioxide is uniformly dispersed in the aqueous solution, and the anti-caking effect is still small. In Comparative Example 6, when the concentration of the fertilizer stock solution is high, the spraying effect is poor, and a uniform powder fertilizer sample is not obtained. Therefore, only when a surfactant with appropriate lengths of hydrophilic and hydrophobic chain segments is selected can it have an anti-caking effect. When the particle size of the inert powder is too large, the anti-caking effect on the powder fertilizer is poor.

[0113] In Examples 1-16, after adding anti-caking agents of different formulas, the moisture absorption per unit mass of the powder fertilizer and the caking rate were significantly reduced. Different anti-caking agent formulas and addition amounts had different anti-caking effects on the powder fertilizer. By comparing Examples 1-4 with Comparative Examples 1-3, it can be seen that when the hydrophobic carbon chain in the surfactant is longer or the hydrophilic group is less, the surfactant forms a hydrophobic layer on the surface of the powder fertilizer, which effectively reduces the moisture absorption of the powder fertilizer, thereby reducing its caking rate. Figure 1 The lumps remaining after 10g powder fertilizer sample was pressed by a pressure mold for 8 days and passed through a 30-mesh screen. The caking rate of powder fertilizer in Examples 1 and 2 was significantly lower than that in Comparative Example 1; in Example 5, by adding microcrystalline cellulose with a larger molecular weight, the adhesion between powder fertilizer particles was reduced, and the caking rate was further reduced; in Examples 6 and 7, by adding fine-grained inert powder, under the use of surfactants, a good anti-caking effect was also achieved. It is worth noting that in Comparative Examples 4-7, the use of inert particles has a smaller anti-hygroscopic effect on powder fertilizer, but the anti-caking effect is obvious. By reducing the particle size of the inert powder and increasing the specific surface area of ​​the inert particles, the anti-caking effect of powder fertilizer is better. Examples 8-13 further tried the performance of anti-caking agents under different formulas, and verified that the surfactant with controllable hydrophilic and hydrophobic carbon chain length was obtained, and the number of carbon atoms at the hydrophobic end was controlled to 8-19, and the hydrophilic group was controlled to 2-10, which can adjust the water solubility of the anti-caking agent system and effectively reduce the moisture absorption of powder fertilizer under certain conditions.

[0114] In Examples 14-16, under the same formulation conditions, by increasing the amount of anti-caking agent added, the effect of the amount of anti-caking agent on the anti-caking effect of powder fertilizer was studied and observed. From the data, it can be seen that the effect of the anti-caking agent increases with the increase in concentration. When the concentration is increased from 5.0% to 6.0%, the moisture absorption and caking rate of the powder fertilizer do not decrease significantly. It is speculated that the water-isolating effect of the surfactant reaches a balance, and continuing to increase the amount of surfactant is not conducive to cost control. Therefore, the amount of anti-caking agent added in the present invention is controlled within 0.5% to 5.0%, taking into account both the anti-caking effect and cost control.

[0115] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0116] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An anti-caking agent, characterized in that It comprises at least one of a surfactant capable of controlling the length of the hydrophilic and hydrophobic segments, a macromolecular surfactant, and an inert powder.

2. An anti-caking agent according to claim 1, characterized in that The anti-caking agent at least includes a surfactant capable of controlling the length of the hydrophilic and hydrophobic segments, and the surfactant capable of controlling the length of the hydrophilic and hydrophobic segments includes at least one of fatty alcohol polyoxyethylene ether, fatty acid methyl ester polyoxyethylene ether, fatty amine polyoxyethylene ether, fatty acid amide, and fatty acid glyceride.

3. An anti-caking agent according to claim 2, characterized in that, The fatty alcohol polyoxyethylene ether, fatty acid methyl ester polyoxyethylene ether, fatty amine polyoxyethylene ether, fatty acid amide and fatty acid glyceride are liquid or paste at room temperature, wherein the number of carbon atoms in the fatty alcohol / fatty acid / fatty amine part (hydrophobic end) is 8-19 and the number of hydrophilic groups is 2-10.

4. An anti-caking agent according to claim 2, characterized in that, The fatty alcohol polyoxyethylene ether includes at least one of AEO-3, AEO-5, and AEO-7; the fatty amine polyoxyethylene ether includes at least one of AC-1202, AC-1203, AC-1205, AC-1210, and AC-1810; the fatty acid amide includes at least one of oleic acid diethanolamide and coconut oil diethanolamide; the fatty acid glyceride includes at least one of hexaglycerol laurate and decaglycerol caprylate.

5. An anti-caking agent according to claim 1, characterized in that, The anti-caking agent at least includes a macromolecular surfactant, which includes a surfactant with a multi-branched structure, or other surfactants with a coexisting cyclic and branched structure, or a high-molecular surfactant with a molecular weight of not less than 5000.

6. An anti-caking agent according to claim 1, characterized in that, The anti-caking agent at least comprises inert powder, and the inert powder comprises at least one of silicon dioxide, talc, kaolin, diatomaceous earth, zinc oxide, calcium oxide and silicate.

7. An anti-caking agent according to claim 1, characterized in that: The anti-caking agent at least comprises inert powder, and the particle size of the inert powder is ≥1000 mesh, or ≥8000 mesh.

8. The method for preparing an anti-caking agent according to claim 1, characterized in that: The following steps are involved: At least one of a surfactant capable of controlling the length of hydrophilic and hydrophobic segments, a macromolecular surfactant, and an inert powder is mixed to obtain an anti-caking agent.

9. An application of an anti-caking agent, characterized in that: Use of the anti-caking agent as described in any one of claims 1 to 7 in powder fertilizer.

10. The use of an anti-caking agent according to claim 9, characterized in that: The raw material of the powder fertilizer is in a liquid state, and the solid content of the powder fertilizer raw material is ≤65%; the dosage of the anti-caking agent is 0.5%-2.5% of the mass concentration of the powder fertilizer raw material; wherein the mass concentration is the solute mass of the raw material; the anti-caking agent is added to the powder fertilizer raw material by a mixing method.

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