WO2008098409A1 - A coating method of mixture film containing sulfur - Google Patents

Abstract

The present invention provides a coating method of mixture film containing sulfur. The method comprises coating molten sulfur and organic materials based coating liquid simultaneously on the surface of fertiliser, by which step molten sulfur and coating liquid mixed on the surface, and then hardening the mixture to form mixed film containing sulfur. Such organic materials can be polymer and/or low mw organic materials. The better application manner should be spray coating. The coating method is suitable for coating mixture film containing 0.1-99.9wt% sulfur. The advantages of the method comprise low difficulty of operation, reasonabletechnical processes, low cost, and so on. The method is applicable for all coated slow released fertilisers containing sulfur in the mixed coat.

Description

 Coating method of sulfur-containing mixture film layer

 The invention relates to a preparation method of a sulfur-containing coated slow-release fertilizer, in particular to a coating method of a sulfur-containing mixture film layer in a coated slow-release fertilizer containing a sulfur-containing mixture film layer, which belongs to the preparation of slow-release fertilizer. Technical field. Background technique

 Slow release fertilizer is the development direction of agricultural fertilizer. At present, one of the key points in the research and development of slow-release fertilizers is to reduce costs and obtain a long release period to broaden the application fields of current slow-release fertilizers.

 Coated slow release fertilizer is an important direction for slow release fertilizer. The coatings are polymers, low molecular weight organics, sulfur and fillers, among which sulfur and fillers are inexpensive, so sulfur and fillers are often used in the envelope of coated slow release fertilizers to reduce costs. The addition of sulphur and fillers to the polymer or low molecular weight organic film layer usually affects the release period of the coated slow release fertilizer. The addition of sulphur and non-permeable filler generally extends the release period. Therefore, it is an effective way to reduce the cost and prolong the release period by adding sulfur to the polymer of the coated slow-release fertilizer or the low-molecular-weight organic film layer to prepare a film-type slow-release fertilizer containing a film mixture of a sulfur-containing mixture.

US 6,617,412 discloses a process for preparing a polyurethane-containing sulfur-containing film-coated slow-release fertilizer which is prepared by mixing sulfur in a reactant isocyanate monomer or a polyol monomer into an isocyanate ester. a sulfur-containing mixture or a polyol-containing monomer mixture, and then repeatedly coating an isocyanate component (isocyanate monomer or isocyanate monomer sulfur-containing mixture) and a polyol monomer component (polyol monomer or polyol) on the surface of the fertilizer The monomer-containing sulfur-containing mixture) forms a polyurethane-containing sulfur mixture film layer on the surface of the fertilizer, and finally obtains a coated slow-release fertilizer coated with a polyurethane sulfur-containing mixture film layer. Since sulfur is added to the isocyanate monomer or the polyol monomer to lower their fluidity, the amount of sulfur added in the isocyanate monomer or the polyol monomer cannot be too high, and the amount of sulfur added in the patent is 30. %~80%, ideally 50%. By using the method disclosed above, when forming a film layer of a certain sulfur-containing mixture, particularly when forming a film layer of a sulfur-containing mixture of a thermosetting polymer, the sulfur content in the film layer of the sulfur-containing mixture of the thermosetting polymer may not be too high, otherwise it may be caused by The fluidity of the coating liquid is seriously deteriorated and the coating cannot be carried out; and, the method disclosed above is used to form a sulfur content gradient distribution in the sulfur-containing mixture film layer, especially when the sulfur content is high, a sulfur content gradient is formed. Cloth is very difficult. In particular, the prior art employs a method in which a mixture of sulfur powder and a coating material is coated to form a film layer containing a sulfur mixture. Since the sulfur powder is a solid filler, the bonding property which sulfur itself can have cannot be exhibited, and therefore even When the polymer solution is coated, the sulfur content should not be too high. Otherwise, the polymer bonding force alone is not enough to bond the sulfur powder well to form a continuous coating with suitable mechanical properties, and the sulfur powder content is excessive. High, the polymer solution must use too much solvent to make the coating liquid have suitable fluidity, which is also disadvantageous. Summary of the invention

 SUMMARY OF THE INVENTION An object of the present invention is to provide a coating method for a sulfur-containing mixture film layer which is convenient, easy to adjust, high in sulfur content, and easy to be stepped.

 A technical solution for achieving the object of the present invention is as follows: A coating method of a sulfur-containing mixture film layer is to simultaneously apply molten sulfur and an organic coating liquid to the surface of the fertilizer, respectively, so that the molten sulfur and the organic coating liquid are in the fertilizer. The surface is composited and further solidified to form a sulfur-containing mixture film layer comprising sulfur and organic matter. The organic matter described herein may be a polymer and/or a low molecular weight organic material, and the fertilizer surface may be a pure fertilizer surface or a pre-coated fertilizer surface.

 In the coating method of the sulfur-containing mixture film layer of the present invention, it is preferred to apply molten sulfur to the surface of the fertilizer by spraying. In the coating method of the sulfur-containing mixture film layer of the present invention, it is preferred to apply an organic coating liquid to the surface of the fertilizer by spraying.

 1%〜99. 9%。 The average mass fraction of the sulphur may be from 0.1% to 99. 9%.

Compared with the prior art, the present invention has the following significant advantages: (1) In the coating method of the sulfur-containing mixture film layer of the present invention, sulfur is a molten sulfur at the time of coating, and sulfur can exert a bonding property even if a sulfur-containing mixture film When the sulfur content of the layer is high and sulfur is the main component, since the sulfur can be bonded to each other in the molten state, the film layer can still have good mechanical properties, and the fluidity of the coating material does not exist when the sulfur content is high. The problem of deterioration, the coating process is still easy to implement; (2) The coating method of the sulfur-containing mixture film layer of the present invention, the heat of the molten sulfur can be directly used for curing the polymer in the polymer sulfur-containing mixture film layer, for example The solvent of the thermoplastic polymer solution volatilizes and solidifies or cures by thermal crosslinking of the thermosetting polymer prepolymer to reduce energy consumption; (3) The coating method of the sulfur-containing mixture film layer of the present invention can be controlled by controlling molten sulfur and organic substances The coating rate ratio of the membrane fluid (such as spray flow ratio), it is easy to form a meaningful sulfur content gradient distribution in the sulfur-containing mixture membrane layer, For example, from the inside to the outside, the sulphur content gradient is low in the middle, high to low or low to high, wherein the height can be as high as 100%, and the low can be as low as 0°/. (this sulfur content The gradient distribution can still have relatively high mechanical properties in the case of a high sulfur content in the sulfur-containing mixture membrane layer, which can increase the low sulfur content and reduce the coating thickness to reduce the slow release fertilizer. The product cost, and the release period of the slow release fertilizer is long; the sulfur content gradient distribution can also be used in the sulfur-containing mixture membrane layer, and the sulfur content is very high in the sulfur-containing mixture membrane layer. High barrier layer, long release period of slow release fertilizer), (4) The coating method of the sulfur-containing mixture membrane layer of the invention has wide application range, is convenient and easy, and eliminates sulfur and polymer (or prepolymerization) The reaction with the low molecular weight organic matter, the process flow is reduced, and the process cost is low. detailed description

 The coating method of the sulfur-containing mixture membrane layer is characterized in that the molten sulfur and the organic coating solution are simultaneously applied to the surface of the fertilizer, so that the molten sulfur and the organic coating solution are compounded on the surface of the fertilizer, and then solidified to form sulfur and A film layer of a sulfur-containing mixture of organic matter. The organic matter may be a polymer and/or a low molecular weight organic material, and the fertilizer surface may be a pure fertilizer surface or a pre-coated fertilizer surface.

 In the coating method of the sulfur-containing mixture film layer of the present invention, the molten sulfur is preferably applied to the surface of the fertilizer by spraying. The organic coating liquid is also preferably applied to the surface of the fertilizer by spraying. That is, the coating method of the sulfur-containing mixture film layer of the present invention is preferably: spraying the molten sulfur onto the surface of the fertilizer while spraying the organic coating liquid from the other nozzle to the surface of the fertilizer to melt the sulfur and the organic matter. The coating liquid is compounded on the surface of the fertilizer and further solidified to form a sulfur-containing mixture film layer containing sulfur and organic matter.

 Of course, it is also possible to apply molten sulfur and an organic coating solution to the surface of the fertilizer in other ways. For example, when the film of the sulfur-containing mixture in the envelope-type slow-release fertilizer coating is prepared by using a drum coating device, the molten sulfur is sprayed on the surface of the fertilizer in the drum, and the rotation is continuously measured. The drum is poured into the organic coating liquid, and the rotating drum will continuously apply the poured organic coating liquid on the surface of the fertilizer to be combined with the sprayed molten sulfur on the surface of the fertilizer.

 The sulfur-containing mixture film layer of the present invention comprises a film layer of a mixture of sulfur and a polymer, a film layer of a mixture of sulfur and a low molecular weight organic substance, and a sulfur, a mixed film layer of a polymer and a low molecular weight organic substance, and the like.

The coating method of the sulfur-containing mixture film layer of the invention can be used for sulfur and unsaturated polyester, epoxy resin, thermosetting polyurethane, unsaturated oil, phenolic resin, amino resin, butadiene rubber, natural rubber, polyisoprene Rubber, styrene butadiene rubber, butyl rubber, ethylene propylene rubber and EPDM rubber Coating of a sulfur-containing mixture film layer composed of one or more thermosetting polymers such as nitrile rubber. It can also be used in sulfur and polyolefin, polystyrene and its copolymers, polyvinyl chloride and its copolymers, acrylonitrile-butadiene-styrene copolymer, thermoplastic polyurethane, thermoplastic polyester, polyamide and nitrocellulose. Coating of a sulfur-containing mixture film layer of one or more thermoplastic polymers. It can also be used for the coating of a sulfur-containing mixture film layer having one or more thermoplastic polymers and one or more thermosetting polymers. Of course, the low sulfur molecular organics may also be present in the sulfur-containing mixture film layer comprising sulfur and polymer as described herein.

 When the sulfur-containing mixture film layer is a film layer formed by combining a thermoplastic polymer and sulfur, the coating liquid for forming the polymer in the sulfur-containing mixture film layer may be a melt, a solution or a dispersion of the thermoplastic polymer. form. When the sulfur-containing mixture film layer is a film layer formed by combining a thermosetting polymer and sulfur, the coating liquid for forming the polymer in the sulfur-containing mixture film layer may be a melt, a solution or a dispersion of the prepolymer. The form may also be in the form of a melt, a solution or a dispersion of a reaction composition (monomer composition, prepolymer composition) which can react to form a polymer. When the sulfur-containing mixture film layer has both a thermoplastic polymer and a thermosetting polymer, the coating liquid may be in a uniform form or in separate forms thereof, for example, the coating liquid of the thermoplastic polymer is a solution, and The coating liquid to form the thermosetting polymer is a prepolymer melt, which are each applied to the surface of the fertilizer simultaneously or sequentially, respectively, and finally combined with each other or with molten sulfur on the surface of the fertilizer.

 The coating method of the sulfur-containing mixture film layer of the invention can also be used for sulfur and low molecular weight organic substances (for example, waxes having a melting point higher than room temperature and mixtures thereof, asphalt and mixtures thereof, and rosin or rosin esters and mixtures thereof, having a melting point higher than room temperature Coating of a sulfur-containing mixture film layer of a low molecular weight polymer such as polyethylene wax. Similarly, the low molecular weight organic matter in the sulfur-containing mixture film layer may be a single low molecular weight organic substance or may contain more than one low molecular weight organic substance.

 The coating liquid for forming the low molecular weight organic substance in the sulfur-containing mixture film layer may be in the form of a melt, a solution or a dispersion of a low molecular weight organic substance, or may be a melt, a solution or a reaction composition of a reaction composition which can react to form a low molecular weight organic substance. In the form of a dispersion or the like, it may also be in the form of a melt, a solution or a dispersion of a mixture of a plurality of low molecular weight organic substances which ultimately forms a low molecular weight organic substance in the film layer of the sulfur-containing mixture. The low molecular weight organic coating liquid is usually in the form of a melt.

When a polymer or a low molecular weight organic substance in a sulfur-containing mixture film layer is formed by reacting more than one reactant (for example, a thermosetting polymer is formed by reacting one or more prepolymers or more than one monomer, and it is also possible Involving curing agents, catalysts, etc., may be to mix all the components of the reactants (including the reaction aid) to form a mixed coating liquid to the surface of the fertilizer, or may be The reactants are respectively applied to the surface of the fertilizer at the same time or sequentially, and the components in the reaction composition may be separately coated on the surface of the fertilizer, and some components are mixed to form a mixed coating liquid and then coated on the surface of the fertilizer. , can also be other ways.

 When the sulfur-containing mixture film layer is a film layer formed by combining one or more polymers with sulfur, or a film layer formed by combining one or more low molecular weight organic substances with sulfur, or a polymer, a low molecular weight organic substance (polymer and When the low molecular weight organic matter can be formed by one or more layers formed by combining sulfur with sulfur, more than one polymer, one or more low molecular weight organic substances or polymers and low molecular weight organic substances may be formulated into a mixed coating liquid to the surface of the fertilizer. Coating, it can also be formulated into several coating liquids, each of which is coated on the surface of the fertilizer. When the formation of the thermosetting polymer in the film layer of the sulfur-containing mixture involves more than one reactant (including an auxiliary agent), all the reactants (including the auxiliary agent) may be formulated into a mixed coating liquid to be applied to the surface of the fertilizer. It can be formulated into several coating liquids, each of which is coated on the surface of the fertilizer. Of course, there are other ways.

 When the sulfur-containing mixture film layer has both a polymer and a low molecular weight organic substance, the coating liquid for forming the polymer in the sulfur-containing mixture film layer and the coating liquid for forming the low molecular weight organic substance in the sulfur-containing mixture film layer The fertilizer surface may be separately coated, or the low molecular weight organic matter may be mixed into the coating liquid for forming the polymer in the sulfur-containing mixture film layer to be applied to the fertilizer surface. A method of applying a low molecular weight organic substance to a coating liquid for forming a polymer in a film layer containing a sulfur mixture together with a surface of a fertilizer is generally employed.

 Of course, the sulfur-containing mixture film layer may contain a solid filler in addition to sulfur, a polymer, and a low molecular weight organic substance. The solid filler may be introduced into the sulfur-containing mixture membrane layer by mixing the solid filler in the molten sulfur, or by mixing the solid filler in the coating liquid for forming the organic substance in the sulfur-containing mixture membrane layer, or may be At the same time, the solid filler is mixed in the molten sulfur and the coating liquid for forming the organic substance in the sulfur-containing mixture film layer, so that the solid filler enters with the molten sulfur and the coating liquid for forming the organic substance in the sulfur-containing mixture film layer. The sulfur-containing mixture is in the film layer. It is also possible to add a solid filler to the coating equipment during or after the application of the molten sulfur and the coating of the organic coating liquid to the surface of the fertilizer, such as a drum coating device, with the flow of fertilizer particles in the coating device. The solid filler is adhered to the film layer of the sulfur-containing mixture. It is also possible to spray a solid filler into the film of the sulfur-containing mixture during or after the application of the molten sulfur and the coating of the organic coating liquid to the surface of the fertilizer. Of course, other suitable methods can also be employed.

In the coating method of the sulfur-containing mixture film layer, in the process of coating the surface of the fertilizer with molten sulfur and coating the organic coating liquid, the fertilizer should be in a flowing state, for example, the fertilizer is in the fluidized bed envelope. The device is in a boiling state, or the fertilizer is in a rolling state due to the rotation of the drum in the drum coating device, and the like. Also, generally, the fertilizer is in a flowing state until the film layer of the sulfur-containing mixture solidifies.

 1%至99.9%。 The average mass fraction of the sulfur may be from 0.1% to 99.9%.

 The coating method of the sulfur-containing mixture film layer of the present invention can be employed in the preparation of a coated slow-release fertilizer containing a sulfur-containing mixed film layer in the coating film. That is, it can be used in the preparation of a slow-release fertilizer coating film, which is a film-type slow-release fertilizer containing a sulfur-containing mixture film layer, or in the preparation of a sulfur-containing mixture film layer, which is only a partial film layer in a slow-release fertilizer coating (for example) One of the layers, two layers or several layers of film) is used as a coated slow release fertilizer.

 A part of a specific embodiment of the coating method of the sulfur-containing mixture film layer of the present invention will be described below by way of individual examples of coating a sulfur-containing mixture film layer on the surface of an industrial granular urea.

 Example 1

 The granular industrial urea with a particle size of 2. 0~4.0 is added to the fluidized bed coating equipment, and the granular urea is in a boiling state, and the granular urea temperature in the fluidized bed is maintained at 70 °C. 5: The molar ratio of triethanolamine to diethylene glycol is 0. 15: 1 The melt and the molten sulfur at about 150 °C are sprayed from the three different nozzles simultaneously to the surface of the granular urea. The spray flow ratio of the three different nozzles is controlled to make the NCO of the spray: -0H The ratio of 1: 1: 1, the average mass fraction of sulfur in the formed polyurethane sulfur-containing mixture layer is 92%, and the quality of the film layer of the polyurethane-containing sulfur mixture is sprayed until the designed coating amount is reached (for example, the final product coating type is slow). 15% of the total urea release). Finally, the polyurethane in the polyurethane sulfur-containing mixture film layer is sufficiently cured, that is, a coated slow-release urea obtained by coating a polyurethane sulfur-containing mixture film layer is prepared.

 Example 2

The granular industrial urea having a particle size of 2.0 to 1.0 is added to the fluidized bed coating device, and the granular urea is in a boiling state, and the temperature of the granular urea in the fluidized bed is maintained at 70 °C. 5: The mixture of 4, 4-diphenylmethane diisocyanate MDI, triethanolamine and diethylene glycol (containing a small amount of catalyst, triethanolamine: diethylene glycol molar ratio of 0. 2: 1, - NC0: -0H molar ratio is 1: 1) Melt and molten sulfur of about 150 °C are sprayed from the two different nozzles simultaneously to the surface of the granular urea and stop spraying at the same time, sulfur and 4-diphenylmethane The spray flow ratio of the mixture of diisocyanate MDI, triethanolamine and diethylene glycol is gradually reduced, and the sulfur mass fraction in the formed polyurethane sulfur-containing mixture layer is distributed in a gradient, from the initial sulfur mass fraction. 98% gradually changed to a sulfur mass fraction of 0% at the end of spraying, and made the whole The average mass fraction of sulfur in the polyurethane sulfur-containing mixture film layer is 30%, and the quality of the polyurethane-containing sulfur mixture film formed by spraying reaches the design coating amount (for example, 15% of the total mass of the final product coated type slow-release urea). Finally, the polyurethane in the polyurethane sulfur-containing mixture film layer is sufficiently cured, that is, a coated slow-release urea obtained by coating a polyurethane sulfur-containing mixture film layer is prepared.

 Example 3

 The granular industrial urea with the particle size of 2. 0~4. 0 is added to the drum coating device with temperature control of 80 °C, and the rotating drum (rotation speed 40r/min) is used to make the granular urea flow in the drum. Mixing a mixture of CYD-115 epoxy resin prepolymer and mixed amine curing agent at a temperature of about 60 °C (mass ratio of epoxy resin prepolymer to mixed amine curing agent to theoretical ratio) melt and about 150 °C The molten sulfur is sprayed from the two different nozzles simultaneously to the surface of the granular urea. By controlling the spray flow ratio, the average mass fraction of sulfur in the formed sulfur-containing sulfur compound mixture layer is 70%. The epoxy resin sulphur mixture film quality reaches the designed coating amount (such as 12% of the total mass of the final product coated slow release urea). Then, stop spraying molten sulfur and continue spraying a mixture of CYD-115 epoxy resin prepolymer and mixed amine curing agent at about 60 °C (the mass ratio of epoxy resin prepolymer to mixed amine curing agent is theoretical ratio) The melt is sprayed until the quality of the formed epoxy film reaches the designed coating amount (for example, 2% of the total mass of the final product coated slow release urea). Finally, the epoxy resin in the envelope is sufficiently cured to prepare a coated slow release urea having a composite film of the epoxy-containing sulfur-containing mixture film and the epoxy resin film layer.

 Example 4

The granular industrial urea with a particle size of 2. (Γ4. 0mm was added to a drum coating device with a temperature control of 70 °C, and the rotating drum (rotation speed 40r/min) was used to make the granular urea flow in the drum, and the pressure inside the drum 0. 15MPa. Spray molten sulfur at a temperature of about 150 °C onto the surface of granular urea, and spray until the quality of the formed sulfur film reaches the designed coating amount (such as 10% of the total mass of the final product coated slow-release urea). Preheating of S-583 type unsaturated polyester containing dibenzoyl peroxide (mass fraction of 1.5%) and butyl phthalate phthalate (20% by mass) at around 60 °C 60 parts of the polymer mixture melt, 60 C or so containing accelerator (mass fraction of 0.3%) of S-583 type unsaturated polyester prepolymer mixture melt 40 parts and 15 CTC or so of molten sulfur respectively from three Different nozzles are sprayed slowly onto the surface of the sulfur film layer (ie, the surface of the pre-coated fertilizer) to control the spray flow ratio of the three different nozzles, so that the average mass fraction of sulfur in the unsaturated polyester sulfur-containing mixture film layer is formed. 20%, the quality of the unsaturated polyester sulfur-containing mixture formed by spraying reaches the design envelope The amount (such as 4% of the total mass of the final product coated slow release urea). Finally, the unsaturated polyester in the unsaturated polyester sulfur-containing mixture film layer is fully cured, that is, the sulfur film layer and the unsaturated polyester are prepared. Sulfur-containing mixture film layer composite package Film-coated slow release urea.

 Example 5

 The granular industrial urea with a particle size of 2. (Γ4. 0mm was added to a drum coating device with a temperature control of 60 °C, and the rotating industrial drum (rotation speed 40r/min) was used to make the granular industrial urea flow in the drum. 150° The molten sulfur around C is slowly sprayed onto the surface of the granular urea, and sprayed until the quality of the formed sulfur film reaches the designed coating amount (such as 10% of the total mass of the final product coated slow-release urea). Then, about 40 °C The styrene-butadiene-styrene block copolymer cyclohexanide solution and the 15 CTC molten sulfur are respectively sprayed from the two different nozzles to the surface of the sulfur film layer (ie, the surface of the pre-coated fertilizer). At the same time, the spraying flow rate of sulfur and styrene-butadiene-styrene block copolymer is gradually reduced, so that the formed styrene-butadiene-styrene block copolymer sulfur-containing mixture film layer is formed. The medium sulfur fraction has a gradient distribution, which is gradually changed from the initial sulfur mass fraction of 90% to the sulfur mass fraction at the end of the spraying, and the formed styrene-butadiene-styrene block copolymer The film quality of the sulfur-containing mixture reaches the design coating amount (such as 7% of the total mass of the final product coated slow-release urea) and the average sulfur content in the sulfur-containing mixture of the styrene-butadiene-styrene block copolymer. The mass fraction is 40%. The cyclohexanide is sufficiently dried to obtain a coated slow release urea having a sulfur film layer and a styrene-butadiene-styrene block copolymer sulfur-containing mixture film composite coating.

 Example 6

 The granular industrial urea having a particle size of 2. 0 to 4. 0 mm was placed in a drum coating device with a temperature control of 50 ° C, and a rotating drum (rotation speed of 40 r/min) was used to flow the granular industrial urea in the drum. The molten sulfur at about 150 °C is slowly sprayed onto the surface of the granular urea, and sprayed until the quality of the formed sulfur film reaches the design coating amount (for example, 10% of the total mass of the final product-coated slow-release urea). Then, about 80 石 of paraffin wax (melting point 60 ° C) melt and 15 CTC of molten sulfur are sprayed from the two different nozzles to the surface of the sulfur film layer (ie, the surface of the pre-coated fertilizer), and sprayed until The quality of the formed paraffin-containing sulfur mixture film reaches the designed coating amount (for example, 6% of the total mass of the final product coated slow-release urea), and the average mass fraction of sulfur in the formed paraffin-containing sulfur mixture film layer is 70%. . After cooling and solidification, a coated slow release urea having a composite film of a sulfur film layer and a paraffin-containing sulfur mixture film layer is prepared.

 Example 7

The granular industrial urea having a particle size of 2. 0~4. 0 is added to a drum coating device with a temperature control of 105 ° C, and the rotating drum (rotation speed 40 r / min) is used to make the granular urea flow in the rotating drum. The molten sulfur of about 15 CTC is slowly sprayed onto the surface of the granular urea, and the 4, 4 - phenylene group at about 50 ° C is used. a mixture of alkane diisocyanate MDI, triethanolamine and diethylene glycol (containing a small amount of a catalyst, a molar ratio of triethanolamine: diethylene glycol is 0. 2: 1, -NC0: -0H molar ratio is 1. 1: 1 The melt is added into the drum, and by controlling the ratio of their addition, the average mass fraction of sulfur in the formed polyurethane sulfur-containing mixture layer is 30%, sprayed and added until the formed polyurethane sulfur-containing mixture film quality reaches the design The amount of coating (such as 10% of the total mass of the final product coated slow release urea). Then, the polyvinyl chloride solution containing dioctyl phthalate (polyvinyl chloride: dioctyl phthalate is used in a mass ratio of 2:1, and the solvent is cyclohexanone) is sprayed on the polyurethane sulfur-containing mixture. The surface of the film layer, until the quality of the PVC film reaches the design coating amount (such as 6% of the total mass of the final product coated slow release urea). The solvent is sufficiently dried to remove the polyurethane in the film layer of the polyurethane sulfur-containing mixture, thereby preparing a film-type slow-release urea in which the polyurethane sulfur-containing mixture film layer and the polyvinyl chloride film layer are combined.

 Example 8

 The granular industrial urea with a particle size of 2. (Γ4. Omm is added to a drum coating device with a temperature of 65 Torr, and the rotating drum (rotation speed 40 r/min) is used to make the granular urea flow in the drum. About 50 ° C Mixture of CYD-115 epoxy resin prepolymer and mixed amine curing agent (the mass ratio of epoxy resin prepolymer to mixed amine curing agent is theoretical ratio, and the mixture contains 10% by mass of plasticizer The melt of dioctyl phthalate) and the molten sulfur at about 150 °C are simultaneously sprayed from the two different nozzles to the surface of the granular urea, and the sulfur-containing mixture of the epoxy resin is formed by controlling the spray flow ratio thereof. The average mass fraction of sulfur in the film is 50%, and the quality of the film layer of the epoxy resin mixture formed until the film is formed reaches the designed coating amount (such as 14% of the total mass of the final product coated slow-release urea). The asphalt at about 100 °C (softening point is 75 ° C) and the molten sulfur at about 150 ° C from the two different nozzles simultaneously to the surface of the epoxy resin mixture layer (ie, the surface of the pre-coated fertilizer) Spraying, By controlling their spray flow ratio, the average mass fraction of sulfur in the formed bituminous sulfur-containing mixture layer is 70%, and the sprayed until the formed bituminous sulfur-containing mixture film quality reaches the design coating amount (such as the final product coating type) 4% of the total mass of the slow-release urea. Finally, the epoxy resin in the epoxy-containing sulfur-containing mixture film layer is sufficiently cured, that is, the epoxy resin sulfur-containing mixture film layer and the asphalt sulfur-containing mixture film layer are prepared. Membrane type slow release urea.

Claims

Claim A coating method of a sulfur-containing mixture film layer, characterized in that: the molten sulfur and the organic coating solution are simultaneously applied to the surface of the fertilizer to combine the molten sulfur and the organic coating liquid on the surface of the fertilizer, and further Curing forms a film layer comprising a sulfur-containing mixture of sulfur and organic matter.  The method of coating a sulfur-containing mixture film layer according to claim 1, wherein the organic substance is a polymer and/or a low molecular weight organic substance.  The method for coating a sulfur-containing mixture film layer according to claim 1, wherein the surface of the fertilizer is coated with molten sulfur by spraying.  The method for coating a sulfur-containing mixture film layer according to claim 3, wherein the organic coating liquid is applied to the surface of the fertilizer by spraying.  1%〜99. 9%。 The average mass fraction of sulfur in the sulfur-containing mixture film layer is 0. 1%~99. 9%.