Renewable material-based furandicarboxylic acid-containing polyurethane controlled release fertilizer coating material, and application and product thereof

Abstract

To provide a renewable material-based furandicarboxylic acid-containing polyurethane controlled release fertilizer coating material, and its application and product.SOLUTION: The present invention relates to a polyurethane controlled release fertilizer coating material produced for the first time by introducing furan ring structure units, and is manufactured via a crosslinking reaction between an isocyanate and a biopolyester polyol product based on furandicarboxylic acid derived from renewable materials (hereinafter, Bio-FDCA). In particular, all of the small-molecule alkyds in the raw materials, including Bio-FDCA, adipic acid, plant-derived oleic acid, acetic acid, glycerol, 1,4-butanediol, and diethylene glycol, are of biological origin. This significantly increases the biomass content, making the material safe and environmentally friendly. Furthermore, by reducing the proportion of furan dicarboxylic acid, the performance of the coating film can be improved, thereby enabling effective cost control and providing high market value.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to the technical field of controlled release fertilizers, particularly to the field of IPC classification number C05G3 / 40, and more particularly to the preparation and use of controlled release fertilizer coatings of fully bio-based polyester polyols containing furandicarboxylic acid. [Background technology]

[0002] Polymer polyols are one of the key raw materials that determine the performance of polyurethane materials. Most commercially available polyester polyols are produced by dehydrating and polycondensing simple adipic acid and small polyols under vacuum and high temperatures. Polyurethane products based on polyester polyols with this structure have excellent properties, including high mechanical strength, oil resistance, heat resistance, and aging resistance, but also have obvious drawbacks, such as poor hydrolysis resistance, salt spray resistance, and aging resistance. To improve these properties, a commonly used approach in the industry is to introduce small amounts of phthalic acid, isophthalic acid, or terephthalic acid (phenyl cyclic dicarboxylic acid) into the system. The addition of aromatic structures not only increases the rigidity of the molecular backbone but also further improves the mechanical properties of polyurethane products. At the same time, the introduction of aromatic structures improves the water resistance and other properties of the material to some extent through steric hindrance and crystallization factors. However, due to the insufficient hydrophobicity of the phthalic acid, the resulting polyester polyols have a short release period when used in controlled-release fertilizers, limiting their use in downstream controlled-release fertilizer applications.

[0003] Bio-based polyester polyols are new materials produced using biological, chemical, and physical methods using renewable biomass as raw materials. The emergence of bio-based materials has made them a new option in the current carbon-neutral era, as they can simultaneously meet the needs of low-carbon environmental protection and the diversifying consumer needs of the market. Bio-based materials offer many advantages, including being green, low-carbon, energy-saving, environmentally friendly, and made from renewable raw materials. They also have excellent biodegradability and can be used in a wide range of applications.

[0004] Chinese patent document CN116515079A discloses a bio-based polyurethane controlled-release fertilizer coating material and a polyurethane controlled-release fertilizer. The coating material is produced by the crosslinking reaction of a bio-based 1,5-pentadiisocyanate compound with a bio-based polyol. The bio-based polyol is produced by the ring-opening polymerization of an epoxidized fatty acid ester, lactic acid, and a bio-based alcohol. The bio-based acid used in this patent is lactic acid, which has a small molecular weight, contains specific polar functional groups, and has a certain degree of hydrophilicity. The esterification reaction of the bio-based alcohol with an esterification catalyst exhibits hydrophobicity, but the hydrophobicity is weak. Therefore, when used as a coating agent for controlled-release fertilizer, the thickness must be increased to improve hydrophobicity and extend the sustained-release period, resulting in higher costs.

[0005] Chinese Patent CN115873200A discloses another biologically-derived polyol for polyurethane used in the production of controlled-release fertilizer, which is obtained by liquefying biomass raw materials such as starch and straw. However, due to the complicated manufacturing process and low biomass content, the controlled-release period can only reach 60 days if the coating rate is slowed down. Only by increasing the coating rate can the controlled-release period be further extended, which also leads to an increase in production costs.

[0006] In view of the shortcomings of existing technologies, the object of the present invention is to provide a polyurethane controlled release fertilizer coating containing furan dicarboxylic acid based on renewable raw materials, which is highly biodegradable, environmentally safe, has strong hydrophobicity, good sealing performance, and is suitable for mass production.

[0007] On the other hand, the present invention also aims to provide a use of a polyurethane controlled release fertilizer coating material containing furan dicarboxylic acid based on the above renewable raw materials.

[0008] On the other hand, another object of the present invention is to provide a product obtained by the above use.

[0009] To achieve the above objectives, the present invention adopts the following technical solutions:

[0010] 1. A polyurethane controlled-release fertilizer coating comprising furan dicarboxylic acid based on renewable raw materials, the polyurethane controlled-release fertilizer coating comprising a structural unit The coating composition includes JPEG2025158053000002.jpg1932 and is obtained by crosslinking a polyester polyol prepared from furandicarboxylic acid based on one or more renewable raw materials with one or more isocyanates. The present invention is the first to introduce a furan ring structure into a polyurethane coating system. Compared to the aromatic benzene ring structure introduced by conventional methods, the furan ring has excellent water resistance and is advantageous for extending the release period of coated controlled-release fertilizers. Furthermore, the present invention prefers furandicarboxylic acid prepared from renewable raw materials as the source of the furan ring, thereby improving the performance of the film material and increasing the biomass content, resulting in greater biocompatibility and ecological safety.

[0011] Preferably, the infrared spectrum of the polyurethane controlled release fertilizer coating material is 1598 to 1600 cm -1 , 1220~1225cm -1 , 1070~1075cm -1 , 818~823cm -1 , and 764-768 cm -1 It has a characteristic peak.

[0012] The polyurethane controlled-release fertilizer coating material of the present invention is obtained by crosslinking polyester polyol of furan dicarboxylic acid (Bio-FDCA) based on renewable raw materials with isocyanate. The infrared spectrum shows that all of the polyurethane controlled-release fertilizer coating materials of the present invention have the corresponding characteristic absorption of dimethylfuran, for example, the stretching vibration peak C=C of the furan ring is at 1598-1600 cm -1 , 1220~1225cm -1 At 1070-1075 cm-1, there is the C=O stretching vibration of the ester group directly connected to the furan ring, and at 818-823 cm-1, there is the C=O stretching vibration of the C-O-C group on the furan ring. -1 and 764-768 cm -1 corresponds to the CH out-of-plane bending vibration of the benzene ring or furan ring of the isocyanate, and among these, 764 to 768 cm -1 The characteristic absorption of 764-768 cm is mainly caused by the CH out-of-plane bending vibration of the furan ring. -1 The characteristic absorption peak intensity at 818-823 cm -1 The absorption peak intensity is significantly greater than that at

[0013] Preferably, the raw materials for producing the polyester polyol include Bio-FDCA, one or more organic monobasic or dibasic acids, one or more polyols, and a catalyst.

[0014] The bio-FDCA used in the present invention is prepared from renewable raw materials such as furfural, furan, hexodiacid, fructose, glucose, and diglycolic acid.

[0015] Preferably, the raw materials for producing the polyester polyol, expressed in parts by weight, include 4 to 40 parts by weight of Bio-FDCA, 17 to 55 parts by weight of an organic monobasic acid or dibasic acid, 30 to 55 parts by weight of a polyol, and 0.05 to 2 parts by weight of a catalyst.

[0016] Preferably, the organic monobasic acid or organic dibasic acid is one or more selected from adipic acid, succinic acid, glutaric acid, sebacic acid, vegetable oleic acid, acetic acid.

[0017] Preferably, the vegetable oleic acid is one or more selected from oleic acid, linoleic acid, erucic acid, ricinoleic acid, soybean oleic acid, rapeseed oleic acid, arachidonic acid, sunflower oleic acid, palmitoleic acid.

[0018] Preferably, the polyol is one or more selected from diethylene glycol, butylene glycol, propylene glycol, pentanediol, hexylene glycol, diethylene glycol, and glycerol.

[0019] The Bio-FDCA, organic monobasic or dibasic acid and polyol used in the present invention are all of biological origin or prepared from biologically derived materials.

[0020] Preferably, the catalyst is any one of an organic titanate catalyst, an organic tin catalyst, and zinc acetate, and more preferably, the organic titanate catalyst is any one of isopropyl titanate and tetrabutyl titanate, and the organic tin catalyst is any one of dibutyltin oxide and dibutyltin dilaurate.

[0021] Preferably, the polyester polyol is prepared from Bio-FDCA, adipic acid, diethylene glycol, glycerin and a catalyst. More preferably, the raw materials for preparing the polyester polyol contain, by weight, 10 to 30 parts of Bio-FDCA, 17 to 40 parts of adipic acid, 35 to 60 parts of diethylene glycol, 0 to 20 parts of glycerin, and 0.05 to 0.2 parts of a catalyst.

[0022] Preferably, the polyester polyol is prepared from Bio-FDCA, adipic acid, vegetable oleic acid, acetic acid, glycerin and a catalyst. More preferably, the raw materials for preparing the polyester polyol include, by weight, 10 to 20 parts of Bio-FDCA, 5 to 15 parts of adipic acid, 40 to 45 parts of vegetable oleic acid, 2 to 10 parts of acetic acid, 30 to 45 parts of glycerin, and 0.05 to 0.2 parts of a catalyst.

[0023] Preferably, the polyester polyol is prepared from Bio-FDCA, adipic acid, butylene glycol, propylene glycol and a catalyst. More preferably, the raw materials for preparing the polyester polyol contain, by weight, 10 to 15 parts of Bio-FDCA, 40 to 50 parts of adipic acid, 33 to 38 parts of butanediol, 17 to 22 parts of propylene glycol, and 0.05 to 0.2 parts of a catalyst.

[0024] Preferably, the amount of Bio-FDCA used is 4 to 40% based on the mass percent of the polyester polyol. More preferably, the amount of Bio-FDCA used is 10 to 30%, and even more preferably, the amount of Bio-FDCA used is 10 to 20%.

[0025] Preferably, the viscosity of the polyester polyol is 500 to 30,000 mPa·s at 25°C. More preferably, the viscosity of the polyester polyol is 1500 to 15000 mPa·s at 25°C.

[0026] Preferably, the polyester polyol is produced by the following method: adding raw materials to a reaction vessel, adding a catalyst, heating the reactants to reflux, and after the reaction, distilling under reduced pressure until the acid value of the system is 2.0 mg KOH / g or less and the water mass fraction is 0.1% or less, and then lowering the temperature and discharging.

[0027] Specifically, the polyester polyol is obtained as follows: Furandicarboxylic acid, adipic acid, diethylene glycol, glycerin, and a catalyst are heated to 150-170°C and refluxed for 5-10 hours. The temperature is then increased to 200-240°C and refluxed until the acid value reaches 5.0 mgKOH / g or less. The mixture is then cooled to 180-220°C and distilled under reduced pressure until the acid value reaches 2.0 mgKOH / g or less. Once the water mass fraction reaches 0.1% or less, the temperature is lowered and the material is released. The polyester polyol has a viscosity of 4000-10000 mPa·s and a hydroxyl value of 150-350 mgKOH / g.

[0028] Alternatively, the polyester polyol can be obtained as follows: Vegetable oleic acid, acetic acid, and glycerin are heated to 160-240°C and esterified until the acid value reaches 10 mgKOH / g or less to obtain vegetable oleic acid glyceride. Then, renewable raw materials such as furandicarboxylic acid, adipic acid, and a catalyst are added, heated to 150-170°C, and refluxed for 5-10 hours. The temperature is then increased to 200-240°C and refluxed until the acid value reaches 5.0 mgKOH / g or less. The mixture is then cooled to 180-220°C and distilled under reduced pressure until the acid value reaches 2.0 mgKOH / g or less. Once the water mass fraction reaches 0.1%, the temperature is lowered and the material is released. The resulting polyester polyol has a viscosity of 7000-10,000 mPa·s and a hydroxyl value of 200-400 mgKOH / g.

[0029] Alternatively, the polyester polyol can be obtained as follows: Furandicarboxylic acid, adipic acid, butylene glycol, propylene glycol, and a catalyst based on renewable raw materials are heated to 150-170°C and refluxed for 5-10 hours. The temperature is then increased to 200-240°C and refluxed until the acid value reaches 5.0 mgKOH / g or less. The mixture is then cooled to 180-220°C and distilled under reduced pressure until the acid value reaches 2.0 mgKOH / g or less. Once the water mass fraction reaches 0.1% or less, the temperature is lowered and the material is released. The polyester polyol has a viscosity of 4000-8000 mPa·s and a hydroxyl value of 200-400 mgKOH / g.

[0030] Preferably, the isocyanate has two or more isocyanate groups. Preferably, the isocyanate includes a petroleum-based or bio-based polymethylene polyphenyl polyisocyanate. More preferably, the diisocyanate is one or more selected from petroleum-based diphenylmethane diisocyanate (MDI), bio-based diphenylmethane diisocyanate, toluene diisocyanate (TDI), terephthalic acid diisocyanate, xylylene diisocyanate (XDI), cyclohexane diisocyanate (CHDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI). More preferably, the bio-based MDI is synthesized from bio-based aniline.

[0031] Preferably, the molar ratio of hydroxyl groups of the polyester polyol to NCO groups of the isocyanate is 1 to 1.05:1.

[0032] Another aspect of the present invention provides a method for using a polyurethane controlled-release fertilizer coating material comprising furan dicarboxylic acid based on renewable feedstocks, the method comprising the steps of spraying the polyester polyol and the isocyanate onto the surface of granular fertilizer and crosslinking them in situ to form a film on the surface of the granular fertilizer to obtain a polyurethane controlled-release fertilizer.

[0033] Preferably, the weight of the polyurethane controlled release fertilizer coating containing the renewable feedstock-based furandicarboxylic acid accounts for 2 to 6% of the weight of the granular fertilizer.

[0034] More preferably, the weight of the polyurethane controlled release fertilizer coating material containing the renewable raw materials-based furandicarboxylic acid accounts for 2 to 4% of the weight of the granular fertilizer.

[0035] Another aspect of the present invention provides a product obtainable by the above method of use, said product being a polyurethane coated controlled release fertilizer.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The polyurethane controlled-release fertilizer coating material of the present invention is made of bio-based materials that have good biocompatibility, are easy to decompose, have high ecological safety, are green and environmentally friendly, and meet the development requirements of green chemistry, and will not cause soil pollution.

[0038] 2. This invention innovatively designs a highly hydrophobic polyester polyol, and by adding only a small amount of Bio-FDCA, the hydrophobic sealing performance of the manufactured polyurethane material is significantly improved, thereby extending the controlled release, which is cost-effective and has real industrial value.

[0039] 3. The polyester polyol designed and synthesized in this invention has a moderate viscosity and can form a film through an in-situ crosslinking process with isocyanate on the surface of fertilizer particles. It is easy to operate and suitable for industrial scale-up of production.

[0040] 4. The polyurethane controlled-release fertilizer coating material of the present invention has good hydrophobicity and airtightness, and can be used to coat fertilizer particles at a lower coverage rate, meaning that a smaller dosage can achieve the same controlled-release effect as existing products on the market, further reducing the cost of using bio-based materials.

[0041] 5. This invention applies Bio-FDCA to the field of controlled release fertilizer coating materials for the first time, and establishes a new bio-based controlled release fertilizer coating material system that can advantageously replace existing bio-based controlled release fertilizers. [Brief explanation of the drawings]

[0042] [Figure 1]1 shows infrared spectra of the polyester polyol (top) and polyurethane controlled-release fertilizer coating (bottom) in Example 1. [Figure 2] 1 is an infrared spectrum of the polyester polyol (top) and polyurethane controlled-release fertilizer coating (bottom) in Example 2. [Figure 3] 1 is an infrared spectrum of the polyester polyol (top) and polyurethane controlled-release fertilizer coating (bottom) in Example 3. [Figure 4] 1 is an infrared spectrum of the polyester polyol (top) and polyurethane controlled-release fertilizer coating (bottom) in Example 5. [Figure 5] 1 is an infrared spectrum of the polyester polyol (top) and polyurethane controlled-release fertilizer coating (bottom) in Example 7. [Figure 6] 1 shows infrared spectra of polyester polyol (top) and polyurethane controlled-release fertilizer coating (bottom) in Comparative Example 1. [Figure 7] 1 shows infrared spectra of polyester polyol (top) and polyurethane controlled-release fertilizer coating (bottom) in Comparative Example 1. [Figure 8] FIG. 2 is a partial enlarged view of characteristic peaks in the infrared spectrum of the polyurethane controlled-release fertilizer coating material of Example 1. [Figure 9] 1 is a photograph of polyester polyol samples, where 1 to 7 correspond to the polyester polyols of Examples 1, 2, 3, 5, 7, and Comparative Examples 1 and 2, respectively. [Figure 10] 1 is a photograph of cured polyurethane film samples, where a to g correspond to the cured polyurethane films of the polyurethane controlled-release fertilizer coatings of Examples 1, 2, 3, 5, and 7 and Comparative Examples 1 and 2, respectively. [Example]

[0043] Specific embodiments of the present invention are further described below in conjunction with examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and are not used to limit the protection scope of the present invention.

[0044] Example 1 This embodiment provides a polyurethane controlled-release fertilizer coating containing furan dicarboxylic acid based on renewable feedstocks, the raw materials for which include a polyester polyol and an isocyanate, where the raw materials for the polyester polyol include, by weight, 11 parts Bio-1, 2 parts FDCA, 39 parts adipic acid, 40 parts diethylene glycol, 12 parts glycerol, and 0.1 parts catalyst zinc acetate. The isocyanate is a petroleum-based MDI, PM-200, purchased from Wanhua Chemical.

[0045] The polyester polyol of this embodiment is produced by the following steps. According to the above weight parts, Bio-FDCA, adipic acid, diethylene glycol, and glycerol were added to a reactor, and a catalyst was added. The reactor was heated to 150°C and refluxed for 6 hours, and then the temperature was raised to 200°C and refluxed for another 6 hours. The acid value was measured, and the reaction was terminated when the acid value was 5.0 mg KOH / g or less. The reactor was then cooled to 180°C and distilled under reduced pressure, and the vacuum was controlled at -0.065 MPa until the acid value was 2.0 mg KOH / g or less. After the water mass fraction was 0.1% or less, the temperature was reduced, and the material was released to obtain polyester polyol.

[0046] This embodiment also provides a method for using the above-mentioned polyurethane controlled-release fertilizer coating material containing furan dicarboxylic acid based on renewable raw materials. This step involves weighing 1 kg of granular urea with a particle size of 2.00 to 4.75 mm, adding it to a high-efficiency coating machine, and heating it to 65°C. The polyester polyol and isocyanate produced in this example are then weighed and divided into four equal portions, each containing 3.28 g of polyester polyol and 1.97 g of isocyanate, where the molar ratio of the hydroxyl groups of the polyester polyol to the NCO groups of the isocyanate is approximately 1:1. Polyester polyol and isocyanate were mixed in parts and sprayed onto the surface of the urea granules. After mixing, the polyurethane controlled-release fertilizer coating material crosslinked in situ on the surface of the urea granules, forming a film. After uniform mixing, the next batch of materials was added and the process continued. This was repeated four times, after which the mixture was allowed to solidify for five minutes. To prevent adhesion, 0.2% paraffin was added based on the total mass of the mixture, and the mixture was cooled to 20°C and released, yielding a polyurethane-coated controlled-release fertilizer. The application rate of the polyurethane controlled-release fertilizer coating material was 2.1 wt% (coverage rate) of the polyurethane-coated controlled-release fertilizer.

[0047] This embodiment also provides a polyurethane-coated controlled-release fertilizer obtained by the above-mentioned method of use.

[0048] Example 2 This embodiment provides a polyurethane controlled-release fertilizer coating containing furan dicarboxylic acid based on renewable feedstocks, the raw materials of which include a polyester polyol and an isocyanate, where the raw materials of the polyester polyol include, by weight, 20 parts by weight of Bio-FDCA, 26 parts by weight of adipic acid, 27.25 parts by weight of diethylene glycol, 16 parts by weight of glycerol, and 0.05 parts by weight of a catalyst, dibutyltin dilaurate. The isocyanate is a petroleum-based MDI, PM-200, purchased from Wanhua Chemical.

[0049] In this example, the method for producing the polyester polyol and the method for using the polyurethane controlled release fertilizer coating material are the same as those in Example 1. The difference is that the amount of polyester polyol per dose is 2.89 g and the amount of isocyanate per dose is 2.36 g.

[0050] Example 3 This embodiment provides a polyurethane controlled-release fertilizer coating containing furan dicarboxylic acid based on renewable feedstocks, the raw materials of which include a polyester polyol and an isocyanate, where the raw materials of the polyester polyol include, by weight, 30 parts by weight of Bio-FDCA, 17 parts by weight of adipic acid, 56 parts by weight of diethylene glycol, and 0.05 parts by weight of a catalyst, dibutyltin dilaurate, and the isocyanate is bio-based MDI purchased from BASF.

[0051] In this example, the method for producing the polyester polyol and the method for using the polyurethane controlled release fertilizer coating material are the same as those in Example 1. The difference is that the amount of polyester polyol per dose is 3.31 g and the amount of isocyanate per dose is 1.94 g.

[0052] Example 4 This embodiment provides a polyurethane controlled-release fertilizer coating containing furan dicarboxylic acid based on renewable raw materials, the raw materials of which include polyester polyol and isocyanate, where the raw materials of the polyester polyol include, by weight, 5 parts by weight of Bio-FDCA, 48 parts by weight of adipic acid, 43 parts by weight of diethylene glycol, and 0.05 parts by weight of a catalyst, dibutyltin dilaurate. The isocyanate is a petroleum-based MDI, PM-200, purchased from Wanhua Chemical.

[0053] In this example, the method for producing the polyester polyol and the method for using the polyurethane controlled release fertilizer coating material are the same as those in Example 1. The difference is that the amount of polyester polyol per dose is 3.80 g and the amount of isocyanate per dose is 1.45 g.

[0054] Example 5 This embodiment provides a polyurethane controlled-release fertilizer coating containing furan dicarboxylic acid based on renewable feedstocks, the manufacturing raw materials of which include a polyester polyol and an isocyanate, where the manufacturing raw materials of the polyester polyol include, by weight, 11.7 parts Bio-FDCA, 12 parts adipic acid, 41 parts soybean oleic acid, 6.7 parts acetic acid, 32.5 parts glycerin, and 0.1 part zinc acetate as a catalyst. The isocyanate is a petroleum-based MDI, PM-200, purchased from Wanhua Chemical.

[0055] The polyester polyol of this embodiment is produced by the following steps. S1. Add soybean oleic acid, acetic acid, and glycerin to a reaction vessel according to the above weight parts, heat to 220°C to carry out the esterification reaction, and check the acid value. After the acid value reaches 10 mg KOH / g or less, reduce the temperature and release the material. A yellow, transparent, viscous liquid, vegetable oleic acid glyceryl ester, is obtained, which can be stored for use.

[0056] S2. Add a corresponding amount of Bio-FDCA and adipic acid to the plant-based oleic acid glyceryl ester obtained in step S1, add a catalyst, heat to 170°C and reflux for 5 hours, then increase the temperature to 220°C and continue refluxing for 6 hours, detect the acid value, and terminate the reaction when the acid value is 5.0 mg KOH / g or less, cool to 200°C and distill under reduced pressure, controlling the vacuum at -0.065 MPa until the acid value is 2.0 mg KOH / g or less, and after the water mass fraction is 0.1% or less, reduce the temperature and release the material to obtain polyester polyol.

[0057] The method of use of the polyurethane controlled release fertilizer coating in this example was the same as in Example 1, except that the amount of polyester polyol per dose was 3.34 g and the amount of isocyanate per dose was 1.91 g.

[0058] Example 6 This embodiment provides a polyurethane controlled-release fertilizer coating containing furan dicarboxylic acid based on renewable feedstocks, the raw materials of which include a polyester polyol and an isocyanate, where the raw materials of the polyester polyol include, by weight, 17 parts Bio-FDCA, 10 parts adipic acid, 42 parts soybean oleic acid, 2.2 parts acetic acid, 44 parts glycerin, and 0.1 parts catalytic zinc acetate, and the isocyanate is bio-based MDI purchased from BASF.

[0059] The method for making the polyester polyol and the method for using the polyurethane controlled release fertilizer coating were the same as in Example 5, except that the amount of polyester polyol was 2.79 g and the amount of isocyanate was 2.46 g.

[0060] Example 7 This embodiment provides a polyurethane controlled-release fertilizer coating containing furan dicarboxylic acid based on renewable raw materials, the raw materials for which include a polyester polyol and an isocyanate, where the raw materials for the polyester polyol include, by weight, 11 parts Bio-FDCA, 45 parts adipic acid, 34 parts butanediol, 19 parts propylene glycol, and 0.1 parts zinc acetate catalyst. The isocyanate is a petroleum-based MDI, PM-200, purchased from Wanhua Chemical.

[0061] The polyester polyol of this embodiment is produced by the following steps. According to the above weight parts, Bio-FDCA, adipic acid, butylene glycol, and propylene glycol were added to a reaction vessel, and a catalyst was added. The vessel was heated to 150°C and refluxed for 4 hours. The temperature was then raised to 200°C, and the reflux reaction was continued for 6 hours. The acid value was measured, and the reaction was terminated when the acid value was 5.0 mg KOH / g or less. The vessel was then cooled to 180°C and distilled under reduced pressure. The vacuum was controlled at -0.065 MPa until the acid value was 2.0 mg KOH / g or less. After the moisture mass fraction was 0.1% or less, the temperature was lowered and the material was released to obtain polyester polyol.

[0062] The method of using the polyurethane controlled release fertilizer coating material in this example is the same as in Example 1.

[0063] Comparative Example 1 This comparative example provides a polyurethane controlled-release fertilizer coating material, the manufacturing raw materials of which include polyester polyol and isocyanate, where the polyester polyol is manufactured according to the method described in Example 5 of Patent CN113512172A, and the isocyanate is MDI, which is PM-200 purchased from Wanhua Chemical.

[0064] This comparative example also provides a method of using the polyurethane controlled release fertilizer coating described above, which is the same as Example 1, except that the amount of polyester polyol per dose is 3.36 g and the amount of isocyanate per dose is 1.89 g.

[0065] Comparative Example 2 This comparative example provides a polyurethane controlled-release fertilizer coating material, the manufacturing raw materials of which include polyester polyol and isocyanate, where the polyester polyol is polyether MN700 purchased from Blue Star Eastern University, and the isocyanate is MDI, PM-200 purchased from Wanhua Chemical.

[0066] This comparative example also provides a method of using the polyurethane controlled release fertilizer coating described above. The method is the same as Example 1, except that the polyester polyol is 3.32 g per dose and the isocyanate is 1.93 g per dose.

[0067] Performance Test 1. Infrared Characterization The test samples of the polyurethane coatings used for the infrared standard were prepared as follows: The polyester polyols and isocyanates of the examples and comparative examples were mixed according to the weight ratio using the corresponding application method, uniformly applied to the surface, and cured at 60°C for 5 minutes to obtain polyurethane films.

[0068] The polyester polyols of each example and comparative example were thinly coated on a quartz sheet and subjected to infrared detection by ATR. The corresponding polyurethane films were cut into 1 cm x 1 cm slices and their infrared spectra were measured. The results are shown in Figures 1 to 7.

[0069] 2. Viscosity test The viscosity of the polyester polyol in each example was tested according to the standard method GB / T12008.7-2010, and the results are shown in Table 1.

[0070] 3. Measurement of hydroxyl value According to the GB / T12008.3-2009 standard, the hydroxyl value of the polyester polyol of each example was measured using the phthalic anhydride method, and the results are shown in Table 1.

[0071] 4. Release Cycle Testing The release cycle of the coated urea in each of the above Examples 1 to 7 and Comparative Examples 1 and 2 was tested using the static water extraction method at 25°C, and the release rate in 2 to 4 hours was calculated as follows: The release rate after 24 hours was calculated as the initial release rate, and the number of days required for the cumulative nutrient release rate to reach 80% was calculated as the release period. The results are shown in Table 1.

[0072] JPEG2025158053000003.jpg176165

[0073] This study demonstrates that polyurethane controlled-release fertilizer coatings made from polyester polyols containing renewable furandicarboxylic acid of the present invention have excellent controlled-release performance and high biocarbon content. Considering cost factors, the system of the present invention can achieve release periods of over 60 days, or even 80 days, even with low dosages of furandicarboxylic acid.

[0074] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art may modify the technical solutions described in the above embodiments or replace some of the technical features with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. 1. A polyurethane controlled-release fertilizer coating comprising furan dicarboxylic acid based on renewable raw materials, the polyurethane controlled-release fertilizer coating comprising a structural unit A polyurethane controlled release fertilizer coating containing furan dicarboxylic acid based on renewable raw materials, characterized in that it is obtained by a crosslinking reaction of a polyester polyol prepared from one or more furan dicarboxylic acid based on renewable raw materials with one or more isocyanates.

2. The infrared spectrum of the polyurethane controlled release fertilizer coating material is 1598 to 1600 cm -１ , 1220-1225cm -１ , 1070-1075cm -１ , 818-823cm -１ , and 764-768 cm -１ 2. The polyurethane controlled release fertilizer coating comprising the renewable feedstock-based furan dicarboxylic acid of claim 1, characterized in that it has a characteristic peak at

3. 2. The polyurethane controlled-release fertilizer coating material comprising furandicarboxylic acid based on renewable raw materials according to claim 1, wherein raw materials for producing the polyester polyol include furandicarboxylic acid based on renewable raw materials, one or more organic monobasic acids or dibasic acids, one or more polyols, and a catalyst, wherein the organic monobasic acids or dibasic acids are selected from one or more of adipic acid, succinic acid, vegetable oleic acid, and acetic acid, and the polyols are one or more selected from diethylene glycol, 1,4-butanediol, and glycerin.

4. The polyurethane controlled-release fertilizer coating containing furandicarboxylic acid based on renewable raw materials according to claim 1, characterized in that the raw materials for producing the polyester polyol, expressed in parts by weight, include 4 to 40 parts by weight of furandicarboxylic acid based on renewable raw materials, 17 to 55 parts by weight of an organic monobasic acid or dibasic acid, and 30 to 55 parts by weight of a polyol.

5. 2. The polyurethane controlled release fertilizer coating material comprising furandicarboxylic acid based on renewable raw materials according to claim 1, wherein the polyester polyol is derived from furandicarboxylic acid, adipic acid, diethylene glycol, glycerol, and a catalyst based on renewable raw materials; alternatively, the polyester polyol is derived from furandicarboxylic acid, adipic acid, vegetable oleic acid, acetic acid, glycerin, and a catalyst based on renewable raw materials; or alternatively, the polyester polyol is derived from furandicarboxylic acid, adipic acid, butylene glycol, propylene glycol, and a catalyst based on renewable raw materials.

6. 6. The polyurethane controlled-release fertilizer coating material containing furandicarboxylic acid based on renewable raw materials according to claim 5, wherein the polyester polyol is obtained by heating furandicarboxylic acid, adipic acid, diethylene glycol, glycerin, and a catalyst to 150-170°C and refluxing for 5-10 hours, then increasing the temperature to 200-240°C and refluxing until the acid value reaches 5.0 mgKOH / g or less, cooling to 180-220°C, and distilling under reduced pressure until the acid value reaches 2.0 mgKOH / g or less, and after the moisture mass fraction reaches 0.1% or less, lowering the temperature and releasing the material; and the polyester polyol has a viscosity of 4000-10000 mPa s and a hydroxyl value of 150-350 mgKOH / g.

7. 6. The polyester polyol of claim 5, wherein the polyester polyol is obtained by heating vegetable oleic acid, acetic acid, and glycerin to 160-240°C and esterifying them until the acid value reaches 10 mgKOH / g or less to obtain vegetable oleic acid glyceride; adding renewable raw material-based furandicarboxylic acid, adipic acid, and a catalyst; heating the mixture to 150-170°C and refluxing for 5-10 hours; subsequently, increasing the temperature to 200-240°C and refluxing until the acid value reaches 5.0 mgKOH / g or less; cooling the mixture to 180-220°C and distilling it under reduced pressure until the acid value reaches 2.0 mgKOH / g or less; and releasing the material after the moisture mass fraction reaches 0.1% or less. The polyester polyol has a viscosity of 7,000-10,000 mPa·s and a hydroxyl value of 200-400 mgKOH / g.

8. 6. The polyurethane controlled-release fertilizer coating material containing furandicarboxylic acid based on renewable raw materials according to claim 5, wherein the polyester polyol is obtained by heating renewable raw material-based furandicarboxylic acid, adipic acid, butylene glycol, propylene glycol, and a catalyst to 150-170°C and refluxing for 5-10 hours, then increasing the temperature to 200-240°C and refluxing until the acid value reaches 5.0 mgKOH / g or less, cooling to 180-220°C, and distilling under reduced pressure until the acid value reaches 2.0 mgKOH / g or less, and after the moisture mass fraction reaches 0.1% or less, lowering the temperature and releasing the material. The polyester polyol has a viscosity of 4000-8000 mPa s and a hydroxyl value of 200-400 mgKOH / g.

9. 5. The polyurethane controlled release fertilizer coating containing renewable feedstock-based furandicarboxylic acid according to claim 4, wherein the amount of the renewable feedstock-based furandicarboxylic acid used is 4 to 40%, based on the weight percent of the polyester polyol.

10. 5. The polyurethane controlled release fertilizer coating containing furan dicarboxylic acid based on renewable feedstocks according to claim 4, wherein the isocyanate comprises a petroleum-based or bio-based polymethylene polyphenyl polyisocyanate, and is one or more selected from the group consisting of petroleum-based diphenylmethane diisocyanate, bio-based diphenylmethane diisocyanate, toluene diisocyanate, terephthalic acid diisocyanate, meta-xylylene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate.

11. 11. A method for using a polyurethane controlled-release fertilizer coating material containing furan dicarboxylic acid based on renewable raw materials according to any one of claims 1 to 10, characterized in that the method comprises the steps of spraying the polyester polyol and the isocyanate onto a surface of granular fertilizer, and crosslinking the polyester polyol and the isocyanate in situ to form a film on the surface of the granular fertilizer, thereby obtaining a polyurethane controlled-release fertilizer.

12. The use according to claim 11, characterized in that the weight of the polyurethane controlled release fertilizer coating containing furandicarboxylic acid based on renewable raw materials accounts for 2 to 6% of the weight of the granular fertilizer.

13. 12. A product obtained by the method of claim 11, characterized in that the product is a polyurethane coated controlled release fertilizer.

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