Xylose residue-based coated material, preparation method thereof and coated controlled-release fertilizer

Abstract

The present application belongs to the technical field of fertilizer, and specifically discloses a xylose residue-based coating material, a preparation method thereof and a coated controlled-release fertilizer. The present application utilizes a mixture C obtained by mixing epoxy resin and wax water-blocking agent and an amine compound to react, obtaining an intermediate product 1; then utilizes xylose residue, polyol and a catalyst to mix and react, obtaining a mixture A, and utilizes isocyanate and an organic metal catalyst to mix, obtaining a mixture B, which are utilized to react on one side of the surface of the intermediate product 1, obtaining an intermediate product 2; then utilizes the mixture C and the amine compound to react on one side of the surface of the intermediate product 2, obtaining the xylose residue-based coating material. The fertilizer is coated to obtain the coated controlled-release fertilizer. The xylose residue-based coated controlled-release fertilizer prepared by the present application not only reduces the dependence on petroleum resources, but also reduces the preparation cost, is beneficial to environmental protection, improves the economic benefit, simultaneously guarantees the slow-release performance of the fertilizer, and effectively improves the utilization rate of the fertilizer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fertilizers, in particular to a xylose residue-based coating material, a preparation method thereof and a coated controlled-release fertilizer. BACKGROUND

[0002] The increasing world population has brought a huge burden of food consumption, and chemical fertilizers, as an important part of agricultural production, have made an important guarantee for food production. However, due to the abuse and unreasonable application of traditional chemical fertilizers, the utilization rate of fertilizers is low, and the loss rate is high, which not only causes waste of chemical fertilizer resources, but also leads to a series of ecological and environmental problems, such as water pollution, soil acidification, and air pollution. At present, slow / controlled-release fertilizers are one of the effective methods to solve the above problems, which are defined as fertilizers that reduce the initial release rate of nutrients by various control mechanisms, and make the nutrients release slowly or be controlled according to the set release period, thereby prolonging the effective period of plant nutrient absorption and utilization. Among them, coated fertilizers can effectively solve the problems of low fertilizer utilization and environmental pollution, and have become one of the important research directions of slow / controlled-release fertilizers.

[0003] According to the different coating materials, coated fertilizers are mainly divided into inorganic coating type, organic polymer coating type and environmentally friendly coating type slow / controlled-release fertilizers. Among them, the main representative of inorganic coating fertilizer is sulfur-coated type, which is to coat water-insoluble inorganic materials on the surface of solid fertilizer particles. This kind of material has low price and will not cause secondary pollution after being applied to soil. However, due to the poor elasticity and easy breakage of the coating material, the nutrient release period is easily shortened, which is difficult to meet the nutrient demand of crops throughout the growth period. The main representative of organic coating fertilizer is organic polymer type, which is to coat organic polymer materials on the surface of solid fertilizer particles. However, since the coating material is mainly derived from petroleum-based polymers, it not only has the problems of high price and non-renewable, but also the material itself is mostly difficult to degrade and remains in the soil to cause environmental pollution. Environmentally friendly fertilizer is mainly to use biomass to develop coating materials to coat on the surface of solid fertilizer particles. This kind of material has the advantages of wide source, low price, renewable and degradable after being applied to soil, and can be used as a potential coating material base for developing coated fertilizers, which has attracted great attention in the academic field.

[0004] Xylose residue is a kind of waste residue obtained by processing corn cob, sugarcane residue and other lignocellulose as main raw materials, which is a good biomass resource. A large amount of xylose residue is produced in the process of production, and the xylose residue is widely available and low in price, but the part used is very little. In fact, xylose residue is a mixture, which is difficult to separate into single component and detailed structure, but it can be determined that xylose residue contains natural high molecular polymers such as cellulose, hemicellulose and lignin, which makes it possible to develop into renewable, degradable, non-toxic and harmless green chemical raw materials. At present, there is no method for using xylose residue to prepare coating material of coated fertilizer.

[0005] Therefore, how to disclose a xylose residue based coating material, a preparation method thereof and a coated controlled-release fertilizer. Using xylose residue as raw material to prepare a degradable film material with low cost, simple preparation, environmental friendliness and good controlled-release effect as the coating layer of controlled-release fertilizer is the technical difficulty consistent with the efforts of the current field. SUMMARY

[0006] Therefore, the present application provides a xylose residue based coating material, a preparation method thereof and a coated controlled-release fertilizer to solve the problems of complex preparation process, high cost and difficulty in degradation in soil of the current coated fertilizer.

[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0008] A preparation method of a xylose residue based coating material, comprising the following steps:

[0009] 1) reacting mixture C and amine compounds to form a first coating layer B, to obtain intermediate product 1;

[0010] 2) reacting mixture A and mixture B on one side of the surface of intermediate product 1 to form a coating layer A, to obtain intermediate product 2;

[0011] 3) reacting mixture C and amine compounds on one side of the surface of the coating layer A of intermediate product 2 to form a second coating layer B, to obtain the xylose residue based coating material;

[0012] Wherein, mixture A is obtained by mixing and reacting xylose residue, polyol and catalyst;

[0013] Mixture B is obtained by mixing isocyanate and organic metal catalyst;

[0014] Mixture C is obtained by mixing epoxy resin and wax water blocking agent.

[0015] Preferably, the mass ratio of the coating layer A to the total mass of the first coating layer B and the second coating layer B is 4-8:2-6.

[0016] Preferably, in the step 1) and step 3), the mass ratio of the mixture C and the amine compound is independently 4-8:1-3;

[0017] In the step 2), the mass ratio of the mixture A and the mixture B is 1-1.6:1.

[0018] In the step 1)-3), the reaction temperature is independently 70-100℃, and the reaction time is independently 10-30min.

[0019] Preferably, the mass ratio of the xylose residue, the polyol and the catalyst is 1-3:2-4:0.06-0.28, the reaction temperature of the xylose residue, the polyol and the catalyst is 140-170℃, and the reaction time is 2-4h;

[0020] The xylose residue includes one or more of the waste residue produced in the preparation of xylose from corncob, sugarcane residue, cottonseed hulls, wheat bran, wheat straw, rice straw, rice hulls and tree bark;

[0021] The polyol includes one or more of polyethylene glycol, polyethylene glycol, glycerol and ethylene glycol;

[0022] The catalyst is an acid solution catalyst.

[0023] Preferably, the mass ratio of the isocyanate and the organic metal catalyst is 22-44:1;

[0024] The isocyanate includes one or more of polymeric DMI 200, polymeric DMI 400, polymeric DMI 600 or polymeric DMI 700;

[0025] The organic metal catalyst includes one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, stannous oleate, zinc naphthenate, zinc isooctoate, bismuth carboxylate, bismuth isooctoate, zirconium carboxylate, phenylmercury propionate and phenylmercury acetate.

[0026] Preferably, the mass ratio of the epoxy resin and the wax water blocking agent is 8-10:0-2;

[0027] The epoxy resin includes one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, linear phenolic type epoxy resin with a degree of polymerization of 2-15, triglycidyl ether resin, tetraglycidyl ether resin, triglycidyl amine resin, tetraglycidyl amine resin, brominated epoxy resin and fluorinated epoxy resin;

[0028] The wax water blocking agent includes one or more of paraffin wax, chlorinated paraffin wax, sulfonated paraffin wax, microcrystalline wax and polyethylene wax.

[0029] Preferably, the amine compound includes one or more of triethylenetetramine, diethylenetriamine, m-phenylenediamine and polyamide.

[0030] Another object of the present application is to provide a xylose residue-based coating material prepared by the preparation method.

[0031] Still another object of the present application is to provide a coated controlled-release fertilizer coated by the xylose residue-based coating material, which is obtained by coating the xylose residue-based coating material on the surface of the fertilizer.

[0032] The mass ratio of the coated controlled-release fertilizer to the fertilizer is 103-108:100.

[0033] Preferably, the fertilizer includes one or more of urea, sulfur-coated urea, ammonium carbonate, ammonium nitrate, ammonium sulfate, potassium chloride, potassium nitrate, di-ammonium hydrogen phosphate and mono-ammonium phosphate; and the average particle size of the fertilizer is 2-5 mm.

[0034] The coating layer of the composite of the epoxy resin and the wax water-blocking agent can be used as a hydrophobic protective shell of the fertilizer, effectively slows down the crushing of the coating layer, reduces the particle breakage of the coated fertilizer during the production and transportation, and simultaneously delays the entry of water molecules into the core layer of the coated fertilizer, thereby prolonging the nutrient release period of the coated fertilizer.

[0035] The present application uses xylose residue as a raw material, replaces the dependence on fossil resources for part of the coating material, and also shows that the xylose residue has the potential for direct utilization to produce biomass materials, and successfully prepares the coated controlled-release fertilizer which is low in price and environment-friendly, and effectively prolongs the controlled-release effect of the coated fertilizer.

[0036] According to the above technical solution, compared with the prior art, the present application has the following beneficial effects:

[0037] 1. The present application uses papermaking waste xylose residue to replace part of petroleum-based raw materials to prepare the coated controlled-release fertilizer, and the xylose residue raw material is not only widely available, low in price and renewable, but also can solve the environmental pollution problem caused by papermaking waste;

[0038] 2. The present application covers the surface of the fertilizer with the combination of the epoxy resin and the wax water-blocking agent, which not only improves the hydrophobicity of the fertilizer, but also improves the hardness of the fertilizer particles, thereby reducing the nutrient release rate of the coated controlled-release fertilizer;

[0039] 3. The preparation process of the present application is simple, the raw material preparation and the coating process are green and have no environmental pollution, meet the nutrient demand of crops during the whole growth period, and greatly reduce the production cost. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings required by the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figure 1 The nitrogen accumulation release amount of the coated controlled-release fertilizer prepared in the embodiments 1-7 of the present application. DETAILED DESCRIPTION

[0042] The present application provides a preparation method of xylose residue-based coated material, comprising the following steps:

[0043] 1) reacting mixture C and amine compounds to form a first coating layer B, to obtain intermediate product 1;

[0044] 2) reacting mixture A and mixture B on one side of the surface of intermediate product 1 to form a coating layer A, to obtain intermediate product 2;

[0045] 3) reacting mixture C and amine compounds on one side of the surface of the coating layer A of intermediate product 2 to form a second coating layer B, to obtain xylose residue-based coated material.

[0046] In the present application, mixture A is obtained by mixing and reacting xylose residue, polyol and catalyst; mixture B is obtained by mixing isocyanate and organic metal catalyst; and mixture C is obtained by mixing epoxy resin and wax water-blocking agent.

[0047] In the present application, the mass ratio of the coating layer A to the total mass of the first coating layer B and the second coating layer B is 4-8:2-6, preferably 4-8:3-5, further preferably 4-8:4, and still further preferably 5-7:4, and more preferably 6:4.

[0048] In the present application, the mass ratio of the first coating layer B to the second coating layer B is 2-5:1-4, preferably 2-4:1-2, and further preferably 2:1.

[0049] In the present application, in steps 1) and 3), the mass ratio of mixture C to amine compounds is independently 4-8:1-3, preferably 4-8:2, further preferably 5-7:2, and still further preferably 6:2.

[0050] In the present application, in step 2), the mass ratio of mixture A to mixture B is 1-1.6:1, preferably 1.1-1.5:1, further preferably 1.2-1.4:1, and still further preferably 1.3:1.

[0051] In the present application, the temperature of the reaction in the steps 1)~3) is independently 70~100℃, and specifically can be 75℃, 80℃, 85℃, 90℃, 95℃; the reaction time is independently 10~30min, and specifically can be 12min, 15min, 16min, 20min, 22min, 25min, 26min.

[0052] In the present application, the mass ratio of the xylose residue, the polyol and the catalyst is 1~3:2~4:0.06~0.28, preferably 1.5~2.5:2.5~3.5:0.1~0.2, further preferably 1.8~2.2:2.8~3.2:0.12~0.16, and again preferably 2:3:0.15; the reaction temperature of the xylose residue, the polyol and the catalyst is 140~170℃, and specifically can be 145℃, 150℃, 155℃, 160℃, 165℃; the reaction time is 2~4h, and specifically can be 2.2h, 2.4h, 2.5h, 2.6h, 2.8h, 3h, 3.2h, 3.5h, 3.8h.

[0053] In the present application, the reaction of the xylose residue, the polyol and the catalyst is preferably carried out under stirring, and the stirring rate is preferably 500~700rpm, and specifically can be 520rpm, 550rpm, 580rpm, 600rpm, 620rpm, 650rpm, 680rpm.

[0054] In the present application, the xylose residue includes one or more of the waste residue produced in the preparation of xylose from corncob, sugarcane residue, cottonseed hulls, wheat bran, wheat straw, rice straw, rice hulls and tree bark.

[0055] In the present application, the polyol includes one or more of polyethylene glycol, polyethylene glycol, glycerol and ethylene glycol.

[0056] In the present application, the catalyst is an acid solution catalyst, and specifically can be one or more of hydrochloric acid, sulfuric acid, carbonic acid, nitric acid and acetic acid; when the acid solution catalyst is sulfuric acid, the mass concentration is 95~99%, and specifically can be 96%, 97%, 98%.

[0057] In the present application, the mass ratio of the isocyanate and the organic metal catalyst is 22~44:1, preferably 25~40:1, further preferably 30~35:1, and again preferably 32:1.

[0058] In the present application, the isocyanate includes one or more of polymeric DMI 200, polymeric DMI 400, polymeric DMI 600 or polymeric DMI 700.

[0059] In the present application, the organic metal catalyst includes one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, stannous oleate, zinc naphthenate, zinc iso-octoate, bismuth carboxylate, bismuth iso-octoate, zirconium carboxylate, phenylmercury propionate and phenylmercury acetate.

[0060] In the present application, the mass ratio of the epoxy resin and the wax water blocking agent is 8-10:0-2, preferably 8-10:0.5-1.5, further preferably 8-10:1, again preferably 8.5-9.5:1, and more preferably 9:1. The content of the wax water blocking agent in the present application is not zero.

[0061] In the present application, the epoxy resin includes one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, linear phenol aldehyde type epoxy resin with a polymerization degree of 2-15, triglycidyl ether resin, tetraglycidyl ether resin, triglycidyl amine resin, tetraglycidyl amine resin, brominated epoxy resin and fluorinated epoxy resin.

[0062] In the present application, the wax water blocking agent includes one or more of paraffin wax, chlorinated paraffin wax, sulfonated paraffin wax, microcrystalline wax and polyethylene wax.

[0063] In the present application, the amine compound includes one or more of triethylenetetramine, diethylenetriamine, m-phenylenediamine and polyamide.

[0064] The present application also provides a xylose residue-based coating material prepared by the preparation method.

[0065] The present application also provides a coated controlled-release fertilizer coated by the xylose residue-based coating material, which is obtained by coating the xylose residue-based coating material on the surface of the fertilizer.

[0066] 1) reacting the mixture C and the amine compound on the surface of the fertilizer to form a first coating layer B to obtain intermediate 1;

[0067] 2) reacting the mixture A and the mixture B on the surface of the intermediate 1 to form a coating layer A to obtain intermediate 2;

[0068] 3) reacting the mixture C and the amine compound on the surface of the intermediate 2 to form a second coating layer B to obtain the coated controlled-release fertilizer.

[0069] In the present application, the mass ratio of the coated controlled-release fertilizer to the fertilizer is 103-108:100; specifically, it can be 104:100, 105:100, 105.5:100, 106:100 or 107:100. In the present application, the ratio represents the coating amount, and the mass ratio of the total mass of the coating layer to the fertilizer is 3-8:100.

[0070] In the present application, the fertilizer comprises one or more of urea, sulfur-coated urea, ammonium carbonate, ammonium nitrate, ammonium sulfate, potassium chloride, potassium nitrate, diammonium hydrogen phosphate and monobasic ammonium phosphate; the average particle size of the fertilizer is 2-5 mm, and can be specifically 2.5 mm, 3 mm, 3.5 mm, 4 mm or 4.5 mm.

[0071] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0072] Embodiment 1

[0073] (1) Start the drum coating machine, set the temperature to 75℃ and the rotating speed to 350 rpm, and keep stable for 5 min, then put the urea fertilizer (average particle size d = 4 mm) in the drum for preheating, until the temperature is constant at 75℃, and keep for 10 min.

[0074] (2) Take 43.2 g of mixture C with a rubber dropper, and slowly and uniformly drop it onto the surface of the urea in the drum, then take 14.4 g of triethylenetetramine, and slowly and uniformly drop it onto the surface of the fertilizer in the drum, and react for 15 min;

[0075] (3) Take 33.6 g of mixture A with a rubber dropper, and slowly and uniformly drop it onto the surface of the fertilizer in the drum, then take 24.0 g of mixture B, and slowly and uniformly drop it onto the surface of the fertilizer in the drum, and react for 10 min;

[0076] (4) Take 21.6 g of mixture C with a rubber dropper, and slowly and uniformly drop it onto the surface of the fertilizer in the drum, then take 7.2 g of triethylenetetramine, and slowly and uniformly drop it onto the surface of the fertilizer in the drum, and react for 15 min, and then cool down to obtain the xylose residue-based coated controlled-release fertilizer. The coating thickness is 5.5% in terms of the percentage of the coating material to the core fertilizer.

[0077] In the present application, the fertilizer comprises one or more of urea, sulfur-coated urea, ammonium carbonate, ammonium nitrate, ammonium sulfate, potassium chloride, potassium nitrate, diammonium hydrogen phosphate and monobasic ammonium phosphate; the average particle size of the fertilizer is 2-5 mm, and can be specifically 2.5 mm, 3 mm, 3.5 mm, 4 mm or 4.5 mm.

[0078] Mixture B: 30 parts of isocyanate (polymerized DMI 400) and 1 part of stannous octoate are mixed to obtain;

[0079] Mixture C: 9 parts of bisphenol A type epoxy resin and 1 part of microcrystalline wax water blocking agent are mixed to obtain.

[0080] The control release performance is determined by the industry standard HG / T4216-2011. The initial dissolution rate of nitrogen in the coated controlled release fertilizer prepared in this example is 6.92%, and the control release period is 25d.

[0081] Example 2

[0082] (1) Start the drum coating machine, set the temperature to 75°C and the rotation speed to 350 rpm. After keeping stable for 5 min, place the urea fertilizer (average particle size d = 4 mm) in the drum for preheating. After the temperature is kept constant at 75°C, keep for 10 min.

[0083] (2) Weigh 48.0 g of mixture C with a rubber head dropper, and slowly and evenly drop it onto the surface of the urea in the drum. Then weigh 16.0 g of triethylenetetramine, and slowly and evenly drop it onto the surface of the fertilizer in the drum. React for 15 min.

[0084] (3) Weigh 54.9 g of mixture A with a rubber head dropper, and slowly and evenly drop it onto the surface of the fertilizer in the step (2). Then weigh 41.1 g of mixture B, and slowly and evenly drop it onto the surface of the fertilizer in the drum. React for 10 min.

[0085] (4) Weigh 24.0 g of mixture C with a rubber head dropper, and slowly and evenly drop it onto the surface of the fertilizer in the step (3). Then weigh 8.0 g of triethylenetetramine, and slowly and evenly drop it onto the surface of the fertilizer in the drum. React for 15 min, and then cool down to obtain the coated controlled release fertilizer based on wood residue. The coating thickness is 7.5% of the core fertilizer.

[0086] The preparation of mixture A, mixture B and mixture C is the same as that in Example 1.

[0087] The control release performance is determined by the industry standard HG / T4216-2011. The initial dissolution rate of nitrogen in the coated controlled release fertilizer prepared in this example is 5.46%, and the control release period is 49d.

[0088] Example 3

[0089] (1) Start the drum coating machine, set the temperature to 75°C and the rotation speed to 350 rpm. After keeping stable for 5 min, place the urea fertilizer (average particle size d = 4 mm) in the drum for preheating. After the temperature is kept constant at 75°C, keep for 10 min.

[0090] (2) Weigh 43.2 g of mixture C with a rubber head dropper, and slowly and evenly drop it onto the surface of the urea in the drum. Then weigh 14.4 g of triethylenetetramine, and slowly and evenly drop it onto the surface of the fertilizer in the drum. React for 15 min.

[0091] (3) Use a rubber head dropper to weigh mixture A 32.0 g, slowly and evenly drop onto the surface of the fertilizer in step (2), then weigh mixture B 25.6 g, slowly and evenly drop onto the surface of the fertilizer in the drum, react for 10 min;

[0092] (4) Use a rubber head dropper to weigh mixture C 21.6 g, slowly and evenly drop onto the surface of the fertilizer in step (3), then weigh triethylenetetramine 7.2 g, slowly and evenly drop onto the surface of the fertilizer in the drum, react for 15 min, then cool down, to obtain the xylose residue-based coated controlled-release fertilizer. The coating thickness is expressed as the percentage of the coating material to the core fertilizer, which is 5.5%.

[0093] Wherein, the preparation of mixture A, mixture B and mixture C is the same as example 1.

[0094] The controlled-release performance is determined by industry standard HG / T 4216-2011. The initial dissolution rate of nitrogen in the coated controlled-release fertilizer prepared in this example is 5.60%, and the controlled-release period is 49 d.

[0095] Example 4

[0096] (1) Start the drum coating machine, set the temperature to 75℃ and the speed to 350 rpm, keep stable for 5 min, then put the urea fertilizer (average particle size d = 4 mm) into the drum for preheating, until the temperature is constant to 75℃, keep for 10 min.

[0097] (2) Use a rubber head dropper to weigh mixture C 43.2 g, slowly and evenly drop onto the surface of the urea in the drum, then weigh triethylenetetramine 14.4 g, slowly and evenly drop onto the surface of the fertilizer in the drum, react for 15 min;

[0098] (3) Use a rubber head dropper to weigh mixture A 30.6 g, slowly and evenly drop onto the surface of the fertilizer in step (2), then weigh mixture B 27.0 g, slowly and evenly drop onto the surface of the fertilizer in the drum, react for 10 min;

[0099] (4) Use a rubber head dropper to weigh mixture C 21.6 g, slowly and evenly drop onto the surface of the fertilizer in step (3), then weigh triethylenetetramine 7.2 g, slowly and evenly drop onto the surface of the fertilizer in the drum, react for 15 min, then cool down, to obtain the xylose residue-based coated controlled-release fertilizer. The coating thickness is expressed as the percentage of the coating material to the core fertilizer, which is 5.5%.

[0100] Wherein, the preparation of mixture A, mixture B and mixture C is the same as example 1.

[0101] The controlled release performance is determined by the industry standard HG / T4216-2011. The initial dissolution rate of nitrogen in the coated controlled release fertilizer prepared in this example is 7.76%, and the controlled release period is 35 days.

[0102] Example 5

[0103] (1) Start the drum coating machine, set the temperature to 75°C and the rotation speed to 350 rpm, and keep stable for 5 min. Then, place the urea fertilizer (average particle size d = 4 mm) in the drum for preheating. After the temperature is kept constant at 75°C, keep for 10 min.

[0104] (2) Weigh 48.0 g of mixture C with a rubber dropper, and slowly and evenly drop it onto the surface of the urea in the drum. Then, weigh 16.0 g of triethylenetetramine, and slowly and evenly drop it onto the surface of the fertilizer in the drum, and react for 15 min.

[0105] (3) Weigh 53.3 g of mixture A with a rubber dropper, and slowly and evenly drop it onto the surface of the fertilizer in the step (2). Then, weigh 42.7 g of mixture B, and slowly and evenly drop it onto the surface of the fertilizer in the drum, and react for 10 min.

[0106] (4) Weigh 24.0 g of mixture C with a rubber dropper, and slowly and evenly drop it onto the surface of the fertilizer in the step (3). Then, weigh 8.0 g of triethylenetetramine, and slowly and evenly drop it onto the surface of the fertilizer in the drum, and react for 15 min. After cooling, the xylan residue-based coated controlled release fertilizer is obtained. The coating thickness is 7.5% of the core fertilizer.

[0107] The mixtures A, B and C are prepared as in Example 1.

[0108] The controlled release performance is determined by the industry standard HG / T4216-2011. The initial dissolution rate of nitrogen in the coated controlled release fertilizer prepared in this example is 4.56%, and the controlled release period is 35 days.

[0109] Example 6

[0110] (1) Start the drum coating machine, set the temperature to 75°C and the rotation speed to 350 rpm, and keep stable for 5 min. Then, place the urea fertilizer (average particle size d = 4 mm) in the drum for preheating. After the temperature is kept constant at 75°C, keep for 10 min.

[0111] (2) Weigh 35.6 g of mixture C with a rubber dropper, and slowly and evenly drop it onto the surface of the urea in the drum. Then, weigh 11.8 g of triethylenetetramine, and slowly and evenly drop it onto the surface of the fertilizer in the drum, and react for 15 min.

[0112] (3) Use a rubber head dropper to weigh mixture A 51.9 g, slowly and evenly drop onto the surface of the fertilizer in step (2), then weigh mixture B 44.1 g, slowly and evenly drop onto the surface of the fertilizer in the drum, react for 10 min;

[0113] (4) Use a rubber head dropper to weigh mixture C 24.0 g, slowly and evenly drop onto the surface of the fertilizer in step (3), then weigh triethylenetetramine 8.0 g, slowly and evenly drop onto the surface of the fertilizer in the drum, react for 15 min, then cool down, to obtain the xylose residue-based coated controlled-release fertilizer. The coating thickness is expressed as the percentage of the coating material to the core fertilizer, which is 7.5%.

[0114] Wherein, mixture A, mixture B and mixture C are prepared as in Example 1.

[0115] The controlled-release performance is determined by using the industry standard HG / T 4216-2011. The initial dissolution rate of nitrogen in the coated controlled-release fertilizer prepared in this example is 4.14%, and the controlled-release period is 35 d.

[0116] Example 7

[0117] (1) Start the drum coating machine, set the temperature to 75℃ and the rotation speed to 350 rpm, keep stable for 5 min, then put the urea fertilizer (average particle size d = 4 mm) into the drum for preheating, until the temperature is constant to 75℃, keep for 10 min.

[0118] (2) Use a rubber head dropper to weigh mixture C 48.0 g, slowly and evenly drop onto the surface of the urea in the drum, then weigh triethylenetetramine 16.0 g, slowly and evenly drop onto the surface of the fertilizer in the drum, react for 15 min;

[0119] (3) Use a rubber head dropper to weigh mixture A 51.9 g, slowly and evenly drop onto the surface of the fertilizer in step (2), then weigh mixture B 44.1 g, slowly and evenly drop onto the surface of the fertilizer in the drum, react for 10 min;

[0120] (4) Use a rubber head dropper to weigh mixture C 24.0 g, slowly and evenly drop onto the surface of the fertilizer in step (3), then weigh triethylenetetramine 8.0 g, slowly and evenly drop onto the surface of the fertilizer in the drum, react for 15 min, then cool down, to obtain the xylose residue-based coated controlled-release fertilizer. The coating thickness is expressed as the percentage of the coating material to the core fertilizer, which is 7.5%.

[0121] Wherein, mixture A, mixture B and mixture C are prepared as in Example 1.

[0122] The controlled release performance of the prepared coated controlled release fertilizer is determined by using the industry standard HG / T4216-2011, and the initial dissolution rate of nitrogen in the prepared coated controlled release fertilizer is 8.75%, and the controlled release period is 56d.

[0123] Figure 1 The figure shows the cumulative release amount of nitrogen in the coated fertilizer prepared in Examples 1-7 at different periods. As can be seen from Examples 1, 3 and 4, when the addition ratio of the mixture A and the mixture B is different, the controlled release period of the coated fertilizer prepared in each example shows a trend of first increasing and then decreasing with the increase of the addition ratio of the mixture A and the mixture B; under the optimized conditions of Example 3, the initial dissolution rate of nitrogen in the prepared coated controlled release fertilizer is 5.60%, and the controlled release period is 49d; compared with Example 3, under the condition of low addition ratio of the mixture A and the mixture B in Example 4, the initial dissolution rate of nitrogen in the prepared coated controlled release fertilizer is increased by 2.16%, and the controlled release period is reduced by 14d; compared with Example 3, under the condition of high addition ratio of the mixture A and the mixture B in Example 1, the initial dissolution rate of nitrogen in the prepared coated controlled release fertilizer is increased by 1.32%, and the controlled release period is reduced by 24d. Similarly, under the condition of the addition ratio of the mixture A and the mixture B in Example 7 and Example 2 from low ratio to high ratio, the controlled release period is reduced from 56d to 49d. These are mainly due to the fact that under the condition of high addition ratio of the mixture A and the mixture B, the reaction between the hydroxyl groups of the xylose residue based polyol in the mixture A and the isocyanate groups in the isocyanate is insufficient, so that the surface of the coating of the fertilizer is difficult to achieve a dense filling state, thereby leading to the fact that the fertilizer particles are easily attacked by water molecules and the controlled release period is reduced.

[0124] As can be seen from Examples 6 and 7, when the addition ratio of the coating material A and the coating material B is fixed, the controlled release period is increased from 35d to 56d when the coating thickness of Example 6 and Example 7 is increased from 5.5% to 7.5%, which shows that the coating thickness also affects the controlled release effect. At the same time, the controlled release results of Example 2 and Example 5 show that it is necessary to consider the effect of the coating material B on the controlled release effect in addition to the effect of the addition ratio of the mixture A and the mixture B on the controlled release period; compared with Example 2, the controlled release period of Example 5 is increased by 14d when the addition amount of the coating material B is increased by 10%, which is mainly due to the fact that the water blocking effect of the coating material B prolongs the controlled release period. In general, good slow release effect is achieved in Examples 1-7 of the present application, and the xylose residue based coated controlled release fertilizer with the desired slow release time can be obtained by controlling the above conditions.

[0125] Example 8

[0126] (1) Start the drum coating machine, set the temperature to 90 °C and the rotation speed to 350 rpm. After 5 min of stabilization, place the potassium chloride fertilizer (average particle size d = 5 mm) in the drum for preheating. When the temperature is constant at 90 °C, keep it for 10 min.

[0127] (2) Weigh 43.2 g of mixture C with a rubber-tipped dropper and slowly and evenly add it to the surface of the potassium chloride in the drum. Then weigh 14.4 g of diethylene triamine and slowly and evenly add it to the surface of the fertilizer in the drum. React for 25 min.

[0128] (3) Weigh 33.6 g of mixture A with a rubber-tipped dropper and slowly and evenly add it to the surface of the fertilizer from step (2). Then weigh 24.0 g of mixture B and slowly and evenly add it to the surface of the fertilizer in the drum. React for 20 min.

[0129] (4) Weigh 21.6 g of mixture C with a rubber-tipped dropper and slowly and evenly add it to the surface of the fertilizer from step (3). Then weigh 7.2 g of diethylene triamine and slowly and evenly add it to the surface of the fertilizer in the drum. React for 15 min and then cool down to obtain the xylose residue-based coated controlled-release fertilizer. The coating thickness is 4% of the core fertilizer, expressed as the percentage of coating material to core fertilizer.

[0130] wherein mixture A: 1 part of wheat straw xylose residue, 3 parts of polyethylene glycol 200 and 0.15 parts of sulfuric acid catalyst (98 wt.%) are mixed and reacted at 140 °C and 500 rpm for 2 h to obtain;

[0131] mixture B: 25 parts of isocyanate (polymeric DMI 600) and 1 part of dibutyl tin diacetate are mixed to obtain;

[0132] mixture C: 8 parts of bisphenol F type epoxy resin and 0.1 parts of chlorinated paraffin water blocking agent are mixed to obtain.

[0133] Example 9

[0134] (1) Start the drum coating machine, set the temperature to 100 °C and the rotation speed to 350 rpm. After 5 min of stabilization, place the potassium nitrate fertilizer (average particle size d = 2 mm) in the drum for preheating. When the temperature is constant at 90 °C, keep it for 10 min.

[0135] (2) Weigh 12.0 g of mixture C with a rubber-tipped dropper and slowly and evenly add it to the surface of the potassium nitrate in the drum. Then weigh 4.0 g of diethylene triamine and slowly and evenly add it to the surface of the fertilizer in the drum. React for 20 min.

[0136] (3) Using a rubber head dropper, weigh out 33.6 g of mixture A and slowly and evenly drop onto the surface of the fertilizer in the drum from step (2). Weigh out 24.0 g of mixture B and slowly and evenly drop onto the surface of the fertilizer in the drum. React for 30 min.

[0137] (4) Using a rubber head dropper, weigh out 6.0 g of mixture C and slowly and evenly drop onto the surface of the fertilizer from step (3). Weigh out 2.0 g of diethylenetriamine and slowly and evenly drop onto the surface of the fertilizer in the drum. React for 10 min and cool down. The coated controlled release fertilizer is obtained. The coating thickness is 3% of the core fertilizer.

[0138] wherein mixture A is obtained by mixing 1 part of cottonseed hulls xylose residue, 3 parts of glycerol and 0.15 parts of sulfuric acid catalyst (98 wt.%) and reacting at 165 °C, 500 rpm for 4 h;

[0139] mixture B is obtained by mixing 40 parts of isocyanate (polymeric DMI 200) and 1 part of bismuth isooctoate;

[0140] mixture C is obtained by mixing 8 parts of triglycidyl ether resin and 2 parts of sulfonated paraffin water barrier.

[0141] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0142] The above description of disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a xylose-slag-based encapsulating material, characterized by, The method comprises the following steps: 1) reacting mixture C and amine compounds to form a first coating layer B, to obtain intermediate product 1; 2) reacting mixture A and mixture B on one side of the surface of intermediate product 1 to form a coating layer A, to obtain intermediate product 2; 3) reacting mixture C and amine compounds on the surface of the coating layer A of intermediate product 2 to form a second coating layer B, to obtain a xylose residue-based coated material; wherein mixture A is obtained by mixing xylose residue, polyol and catalyst; mixture B is obtained by mixing isocyanate and organic metal catalyst; mixture C is obtained by mixing epoxy resin and wax water blocking agent; the mass ratio of xylose residue, polyol and catalyst is 1-3:2-4:0.06-0.28, the reaction temperature of xylose residue, polyol and catalyst is 140-170℃, and the reaction time is 2-4h; the xylose residue comprises one or more of corn cob, sugarcane residue, cottonseed hull, wheat bran, wheat straw, rice straw, rice hull and tree bark, which are waste residues generated in the preparation of xylose; the polyol comprises one or more of polyethylene glycol, polyethylene glycol, glycerol and ethylene glycol; the catalyst is an acid solution catalyst.

2. The method for preparing a xylose residue-based coating material according to claim 1, characterized in that, the mass ratio of the coating layer A to the total mass of the first coating layer B and the second coating layer B is 4-8:2-6.

3. The method for preparing a xylose residue-based coating material according to claim 2, characterized in that, in steps 1) and 3), the mass ratio of mixture C to amine compounds is 4-8:1-3; in step 2), the mass ratio of mixture A to mixture B is 1-1.6:1; the reaction temperature in steps 1)-3) is 70-100℃, and the reaction time is 10-30min.

4. The method for preparing a xylose residue-based coating material according to claim 1, characterized in that, the mass ratio of isocyanate to organic metal catalyst is 22-44:1; the isocyanate comprises one or more of polymeric DMI200, polymeric DMI400, polymeric DMI600 or polymeric DMI700; the organic metal catalyst comprises one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, stannous oleate, zinc naphthenate, zinc isooctoate, bismuth carboxylate, bismuth isooctoate, zirconium carboxylate, phenylmercury propionate and phenylmercury acetate.

5. The method for preparing a xylose residue-based coating material according to claim 4, characterized in that, the mass ratio of epoxy resin to wax water blocking agent is 8-10:0-2; the content of the wax water blocking agent is not zero; the epoxy resin comprises one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, linear phenolic type epoxy resin with a polymerization degree of 2-15, triglycidyl ether resin, tetraglycidyl ether resin, triglycidyl amine resin, tetraglycidyl amine resin, brominated epoxy resin and fluorinated epoxy resin; the wax water blocking agent comprises one or more of paraffin wax, chlorinated paraffin wax, sulfonated paraffin wax, microcrystalline wax and polyethylene wax.

6. A method for preparing a xylose residue-based coating material according to claim 4 or 5, characterized in that, the amine compound comprises one or more of triethylene tetramine, diethylene triamine, m-phenylenediamine and polyamide.

7. The xylose residue-based coated material prepared by the preparation method of any one of claims 1-6.

8. The coated controlled release fertilizer coated with the xylose residue-based coating material according to claim 7, characterized in that, Preparation of the xylose residue-based coated material on the surface of the fertilizer to obtain a coated controlled-release fertilizer; the mass ratio of the coated controlled-release fertilizer to the fertilizer is 103-108:

100.

9. The coated controlled release fertilizer of claim 8, wherein the coating comprises a polymer. The fertilizer comprises one or more of urea, sulfur-coated urea, ammonium carbonate, ammonium nitrate, ammonium sulfate, potassium chloride, potassium nitrate, di-ammonium hydrogen phosphate and mono-ammonium phosphate; The average particle size of the fertilizer is 2-5 mm.

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