阅读说明：本技术 一种以葵二酸副产脂肪酸合成的聚酯多元醇聚氨酯控释肥膜材料 (Polyester polyol polyurethane controlled-release fertilizer film material synthesized by sebacic acid byproduct fatty acid ) 是由 钟成虎 于 2021-06-02 设计创作，主要内容包括：本发明公开了一种以葵二酸副产脂肪酸合成的聚酯多元醇聚氨酯控释肥膜材料,涉及控释肥包膜材料技术领域。本发明是通过葵二酸副产脂肪酸与苯二甲酸(酐)、二甘醇或二甘醇和甘油、己二酸等合成高性能生物基聚酯多元醇,再与聚合MDI在肥料表面进行交联成膜,葵二酸副产脂肪酸为蓖麻油生产葵二酸所得副产品物精制而成,价格低廉,使用葵二酸副产脂肪酸合成的聚酯多元醇制得的控释肥,不仅产品性能优良,而且经济,具有非常好的性价比,施入土壤后降解好,是高性能、低成本和环保的完美结合,同时也是对葵二酸副产品进行综合利用的有效举措。(The invention discloses a polyester polyol polyurethane controlled-release fertilizer film material synthesized by sebacic acid byproduct fatty acid, and relates to the technical field of controlled-release fertilizer coating materials. The invention synthesizes high-performance bio-based polyester polyol by the sebacic acid by-product fatty acid and phthalic acid (anhydride), diethylene glycol or diethylene glycol, glycerol, adipic acid and the like, and then carries out crosslinking film formation with polymeric MDI on the surface of the fertilizer, the sebacic acid by-product fatty acid is refined from the byproduct of castor oil production sebacic acid, the price is low, the controlled release fertilizer prepared by using the polyester polyol synthesized by the sebacic acid by-product fatty acid has excellent product performance, is economic, has very good cost performance, is good in degradation after being applied to soil, is perfect combination of high performance, low cost and environmental protection, and is an effective measure for comprehensively utilizing the sebacic acid by-product.)

1. A polyester polyol polyurethane controlled release fertilizer film material synthesized by sebacic acid by-product fatty acid is characterized in that the component polyester polyol in the polyurethane controlled release fertilizer film material is prepared by reacting sebacic acid by-product fatty acid with other raw materials, and the sebacic acid by-product fatty acid is prepared by refining a by-product generated by producing sebacic acid from castor oil; the sebacic acid byproduct fatty acid comprises the main component C₁₈H₃₄O₃、C₁₈Unsaturated fatty acid C₁₈H₃₄O₂、C₁₆Unsaturated fatty acid C₁₆H₃₀O₂Three fatty acids;

said C is₁₈H₃₄O₃The structural formula of (A) is:

said C is₁₈H₃₄O₂The structural formula of (A) is:

said C is₁₆H₃₀O₂The structural formula of (A) is:

2. the controlled-release polyester polyol polyurethane fertilizer film material synthesized from sebacic acid by-product fatty acid as claimed in claim 1, wherein when the polyester polyol is prepared by reacting sebacic acid by-product fatty acid, phthalic acid and alcohol, the formula of the controlled-release polyester polyol is the polyester polyol synthesized by reacting sebacic acid by-product fatty acid, phthalic acid, diethylene glycol, glycerol and adipic acid, and the hydroxyl value of the polyester polyol is 170-350 mgKOH/g.

3. The polyester polyol polyurethane controlled-release fertilizer film material synthesized from sebacic acid by-product fatty acid as claimed in claim 2, wherein the phthalic acid comprises terephthalic acid, phthalic acid (anhydride) and isophthalic acid;

the structural formula of the terephthalic acid isThe structural formula of the phthalic acid (anhydride) is shown asThe structural formula of the isophthalic acid is

4. The controlled-release polyester polyol polyurethane fertilizer film material synthesized from sebacic acid by-product fatty acid as claimed in claim 3, wherein when the phthalic acid is terephthalic acid as a main molecular structure, the molecular structural formula of the synthesized polyester polyol is shown in the specification

5. The controlled-release polyester polyol polyurethane fertilizer film material synthesized from sebacic acid by-product fatty acid as claimed in claim 3, wherein when phthalic acid is phthalic acid (anhydride) as a main molecular structure, the molecular structural formula of the synthesized polyester polyol is as follows

6. The controlled-release polyester polyol polyurethane fertilizer film material synthesized from sebacic acid by-product fatty acid as claimed in claim 3, wherein when the phthalic acid is isophthalic acid as a main molecular structure, the molecular structural formula of the synthesized polyester polyol is shown in the specification

7. The polyester polyol polyurethane controlled-release fertilizer film material synthesized from sebacic acid by-product fatty acid as claimed in claim 2, wherein the synthesis method of the polyester polyol comprises the following steps:

(1) firstly, placing the sebacic acid by-product fatty acid and glycerol into a reactor, heating to 160-240 ℃, carrying out esterification reaction, preserving heat at 160-240 ℃ for 1-6 hours, cooling after the acid value is reduced to below 10mgKOH/g to obtain yellow transparent viscous liquid, namely sebacic acid by-product fatty acid glyceride, and keeping the yellow transparent viscous liquid for subsequent reaction;

(2) and (2) adding diethylene glycol, glycerol, phthalic acid (anhydride) and the sebacic acid by-product fatty glyceride obtained in the step (1) into a reaction container, then adding a catalyst, heating for reflux reaction, keeping the temperature at 220-260 ℃ and detecting the acid value, cooling to 180-220 ℃ when the acid value is reduced to be below 5mgKOH/g, starting vacuum rectification, controlling the vacuum degree to be-0.065-0.095 until the acid value of the rectified product is reduced to be below 1.0mgKOH/g and the mass fraction of water is less than 0.1%, cooling and discharging to obtain the polyester polyol.

8. The polyester polyol polyurethane controlled-release fertilizer film material synthesized from sebacic acid by-product fatty acid as claimed in claim 7, wherein in the step (1), the molar ratio of sebacic acid by-product fatty acid to glycerol is 1 (1-1.5).

9. The polyester polyol polyurethane controlled-release fertilizer film material synthesized from sebacic acid by-product fatty acid as claimed in claim 7, wherein in the step (2), the weight ratio of each reactant is as follows: diethylene glycol, glycerin: 20-50%; phthalic acid (anhydride): 30-40%; sebacic acid by-product fatty acid glyceride: 20 to 50 percent.

10. The polyester polyol polyurethane controlled-release fertilizer film material synthesized from sebacic acid by-product fatty acid as claimed in claim 7, wherein the catalyst is an esterification catalyst; the esterification catalyst comprises any one of an organic titanate catalyst, an organic tin catalyst, calcium oxide and zinc acetate; the organic titanate catalyst is any one of isopropyl titanate and butyl titanate.

Technical Field

The invention relates to the technical field of controlled release fertilizer coating materials, in particular to a polyester polyol polyurethane controlled release fertilizer film material synthesized by sebacic acid by-product fatty acid.

Background

Sebacic acid is a main raw material for manufacturing nylon fibers, the yield of sebacic acid in China accounts for ninety percent of the world, and the preparation method in China currently uses castor oil as a raw material. Castor oil is produced by hydrolysis, cracking, acidification, etc. and produces a large amount of by-products during the production process, which mainly contain some fatty acids and their sodium soaps, as well as water, phenol and organic polymer components. The fatty acid is a main by-product (called pelargonium lipid for short) in the production process of the pelargonium diacid, accounts for 60 percent of the yield of the pelargonium diacid, and the composition, the fatty acid components and the properties of the by-product fatty acid are fundamentally changed due to high-temperature cracking, and phenolic substances which are harmful to the environment and human bodies are added in the by-product fatty acid. Due to complex composition and difficult separation, the method is generally discarded, on one hand, the method causes environmental pollution, and on the other hand, valuable fatty acid contained in byproducts cannot be fully utilized, so that the method is extremely waste. The added value of the fatty acid is low, the price is low, the market is not available, a large amount of overstocking is caused, and a great burden is caused to the production of the sebacic acid.

The sebacic acid byproduct fatty acid is mainly used at present: can be used for synthesizing lubricating grease, lubricant and surfactant, preparing raw materials of biodiesel and soap, even being discarded, and has low industrial value. And almost no reports exist on the polyurethane controlled-release membrane material for synthesizing the polyester polyol by using the sebacic acid byproduct fatty acid.

The Chinese invention patent with the patent number of 201210137099.0 discloses a method for preparing polyester polyol by using illegal cooking oil, which comprises the following steps: mixing and reacting the illegal cooking oil, the catalyst and the initiator for 1-5 hours, introducing nitrogen or inert gas for protection in the reaction process, and heating to 100-300 ℃; mixing the product obtained by the reaction in the step and phthalic anhydride for reaction for 5-10 hours, introducing nitrogen or inert gas for protection in the reaction process, and heating to 100-300 ℃; and mixing the reaction product obtained in the step and sodium carbonate for reaction for 1-3 hours, vacuumizing and dehydrating in the reaction process, and heating to 100-150 ℃ and the vacuum degree is less than 0.08 MPa. Although the invention can utilize the illegal cooking oil to prepare the polyester polyol, the method cannot be widely used because the illegal cooking oil has complex and unstable components, high production cost and complex process.

The Chinese invention patent with the patent number of 201310655152.0 discloses a method for preparing illegal cooking oil modified polyester polyol by utilizing recovered alcohol and illegal cooking oil. The method comprises the steps of putting a low-molecular-weight polyol raw material, illegal cooking oil and a catalyst into a polyester reaction kettle; heating to 140-150 ℃, and reacting for 1-1.5 h; introducing N2, continuously heating to 180-190 ℃, and reacting for 1.5-2 h; continuously heating to 220-230 ℃, and preserving heat for 4-5 h; stopping heating, cooling to 120 ℃, closing nitrogen, vacuumizing, reacting for 1.5-2 h, and stopping reaction when the water content of the product is less than or equal to 0.07; finally, cooling to below 75 ℃ and discharging. The method has complex process and unstable product performance, and is not suitable for popularization.

The Chinese patent with patent number 201610370195.8 discloses the preparation of castor oil polyester polyol and the application of the castor oil polyester polyol in controlled release fertilizer. Castor oil is used as a raw material, small molecular alcohol is used as a modifier, castor oil polyol with a high hydroxyl value is prepared through ester exchange reaction under the action of a catalyst, and polybasic acid or anhydride is used as the modifier to perform catalytic condensation reaction to prepare castor oil polyester polyol with a hydroxyl value of 200-350 mgKOH/g. The coated controlled-release fertilizer is prepared by in-situ reaction by using castor oil polyester polyol as a white material and isocyanate as a black material. According to the method, the polyester polyol is prepared by modifying the castor oil, the coated controlled release fertilizer is further prepared, the castor oil modification process is uncontrollable, the price of the castor oil is relatively high, and the production cost is increased.

Disclosure of Invention

In order to solve the problems and fully develop the new application of the sebacic acid byproduct fatty acid, the invention provides a polyester polyol polyurethane controlled-release fertilizer film material synthesized from the sebacic acid byproduct fatty acid.

Specifically, the invention is realized by the following technical scheme:

1. a polyester polyol polyurethane controlled release fertilizer film material synthesized by sebacic acid by-product fatty acid is providedThe polyester polyol in the polyurethane controlled release fertilizer film material is prepared by reacting sebacic acid by-product fatty acid with other raw materials, wherein the sebacic acid by-product fatty acid is prepared by refining by-products generated by producing sebacic acid from castor oil; the sebacic acid byproduct fatty acid comprises the main component C₁₈H₃₄O₃、C₁₈Unsaturated fatty acid C₁₈H₃₄O₂、C₁₆Unsaturated fatty acid C₁₆H₃₀O₂Three fatty acids;

wherein, C₁₈H₃₄O₃The structural formula of (A) is:

C₁₈H₃₄O₂the structural formula of (A) is:

C₁₆H₃₀O₂the structural formula of (A) is:

further, when the polyester polyol is prepared by reacting sebacic acid by-product fatty acid, phthalic acid and alcohol, the formula is the polyester polyol prepared by reacting sebacic acid by-product fatty acid, phthalic acid, diethylene glycol, glycerol and adipic acid, and the hydroxyl value of the polyester polyol is 170-350 mgKOH/g.

Preferably, the phthalic acid includes terephthalic acid, phthalic acid (anhydride), and isophthalic acid;

the structural formula of terephthalic acid isThe structural formula of phthalic anhydride is(anhydride)) (ii) a The structural formula of the isophthalic acid is

Further, when the phthalic acid is terephthalic acid as a main molecular structure, the molecular structural formula of the synthesized polyester polyol is shown in the specification

Further, when phthalic acid (phthalic anhydride) is taken as a molecular structure main body, the molecular structural formula of the synthesized polyester polyol is shown in the specification

Further, when the phthalic acid is the isophthalic acid as the main molecular structure, the molecular structural formula of the synthesized polyester polyol is shown in the specification

Further, the synthesis method of the polyester polyol comprises the following steps:

(1) firstly, placing the sebacic acid by-product fatty acid and glycerol into a reactor, heating to 160-240 ℃, carrying out esterification reaction, preserving heat at 160-240 ℃ for 1-6 hours, cooling after the acid value is reduced to below 10mgKOH/g to obtain yellow transparent viscous liquid, namely sebacic acid by-product fatty acid glyceride, and keeping the yellow transparent viscous liquid for subsequent reaction;

(2) and (2) adding diethylene glycol, glycerol, phthalic acid (anhydride) and the sebacic acid by-product fatty glyceride obtained in the step (1) into a reaction container, then adding a catalyst, heating for reflux reaction, keeping the temperature at 220-260 ℃ and detecting the acid value, cooling to 180-220 ℃ when the acid value is reduced to be below 5mgKOH/g, starting vacuum rectification, controlling the vacuum degree to be-0.065-0.095 until the acid value of the rectified product is reduced to be below 1.0mgKOH/g, and cooling and discharging after the mass fraction of water is lower than 0.1%, thus obtaining the polyester polyol.

Furthermore, in the step (1) of the method for synthesizing the polyester polyol, the molar ratio of the sebacic acid by-product fatty acid to the glycerol is 1 (1-1.5).

Furthermore, in the step (2) of the synthesis method of the polyester polyol, the weight ratio of each reactant is as follows: diethylene glycol, glycerin: 20-50%; phthalic acid (anhydride): 30-40%; sebacic acid by-product fatty acid glyceride: 20 to 50 percent.

Preferably, the catalyst in the synthesis method of the polyester polyol is an esterification catalyst; the esterification catalyst comprises any one of organic titanate catalyst, organic tin catalyst, calcium oxide and zinc acetate; the organic titanate catalyst is any one of isopropyl titanate and butyl titanate.

The polyester polyol polyurethane controlled release fertilizer film material of the invention has at least the following beneficial effects:

1. the main raw material of the polyester polyol is sebacic acid by-product fatty acid, and the by-product fatty acid is limited in application and even discarded, so that great waste and environmental pollution are caused.

2. The polyurethane coated controlled-release fertilizer prepared by the novel polyester polyol has the advantages that the polyurethane film on the surface is a novel bio-based degradable coated material, and the detection report result shows that: the biological decomposition rate of the controlled release fertilizer film material can reach 31.2 percent. The coating rate is 2.0-3.5%, the release period can reach 60-150 days, the nutrients required by the growth of various crops are met, the controlled release effect on the growth of plants can be realized, the coating material is degradable, the environment is not polluted, the soil is not damaged, and the wide popularization and application value is realized.

3. The invention researches a new material, namely, the byproduct fatty acid of sebacic acid is taken as a raw material, polyester polyol is synthesized, and the polyester polyol is utilized to prepare a novel polyurethane controlled-release fertilizer coating material, wherein the byproduct fatty acid of sebacic acid is refined from the byproduct of sebacic acid produced by castor oil, the price is low, the source is wide, the price is 4000-5000 yuan/ton, which is far lower than the price of 11000-15000 yuan/ton of castor oil, and is also lower than the price of conventional vegetable oil (soybean oil, palm oil, flax oil and the like), and the price of the prepared polyester polyol is 6000-7000 yuan/ton, so the production cost is very low; the polyurethane coated controlled-release fertilizer prepared by using the polyester polyol synthesized by the sebacic acid byproduct fatty acid has the advantages of excellent product performance, economy, very good cost performance and price advantage, and capability of greatly improving the competitiveness of similar products in the market.

4. The polyurethane controlled-release fertilizer coating material prepared by the invention has the advantages of stable components, stable structure and stable performance, the product quality is stable, and the polyurethane controlled-release fertilizer coating material can be used by farmers at ease.

Detailed Description

The following examples are provided to more clearly illustrate the technical solutions of the present invention, and should not be construed as limiting the scope of the present invention.

Example 1

A production method of sebacic acid byproduct polyester polyol comprises the following steps:

1) firstly, placing 1mol of sebacic acid by-product fatty acid and 1mol of glycerol into a reactor, then heating to 160 ℃, carrying out esterification reaction, preserving heat at 160 ℃ for 3 hours, cooling when the acid value is reduced to 1.50mgKOH/g, obtaining yellow transparent viscous liquid, namely sebacic acid by-product fatty acid glyceride, and keeping the yellow transparent viscous liquid for subsequent reaction;

2) adding 330g of diethylene glycol, 10g of glycerol, 100g of phthalic anhydride, 300g of terephthalic acid and 260g of sebacic acid by-product fatty glyceride obtained in the step 1) into a reaction container, then adding an isopropyl titanate catalyst, heating and refluxing for reaction, keeping the temperature at 220 ℃, detecting the acid value, cooling to 180 ℃ when the acid value is reduced to 1.50mgKOH/g, starting vacuum rectification, controlling the vacuum degree to be-0.065-0.095 mPa until the acid value of the rectified product is reduced to below 1.0mgKOH/g and the water mass fraction reaches 0.08%, and cooling and discharging to obtain the polyester polyol.

Secondly, according to GB/T12008.3-2009, the hydroxyl value of the obtained polyester polyol is 180.5mgKOH/g, and the viscosity is 15100CPS/25 ℃ by measuring with a phthalic anhydride method.

Example 2

A method for preparing a polyurethane coated controlled release fertilizer by using the polyester polyol synthesized in example 1 comprises the following steps:

weighing 1 kg of granular urea with the particle size of 2.00-4.75 mm, adding the granular urea into a sugar-coating machine, and heating at the temperature of 60 ℃; 2.8g of polymeric MDI and 4.2g of polyester polyol are mixed and stirred and then added on the surface of the granular urea, the polyurethane film starts to perform cross-linking reaction on the surface of the granular urea, the viscosity is increased, and a compact and tough polyurethane film is formed after the coating material is gradually cured on the surface of the urea for 3-5 minutes and dispersed, wherein the coating rate is 0.7 percent. This was repeated 3 times, and 2.8g of polymeric MDI and 4.2g of polyester polyol were added for the second and third times, respectively, until the coating rate was 2.1%. And finally, adding paraffin accounting for 0.2 percent of the total mass of the fertilizer to prevent the fertilizer particles from being adhered, and cooling to 20 ℃ to obtain the polyester polyol polyurethane coated urea synthesized by sebacic acid by-product fatty acid.

Second, testing the controlled release performance of the coated controlled release fertilizer

The nutrient release period of the coated controlled release fertilizer was tested by hydrostatic extraction at 25 c, expressed as days required for the cumulative nutrient release rate to reach 80%.

The nutrient release period of the coated controlled release fertilizer prepared in this example 2 was 60 days.

In order to illustrate the biodegradability of the coating material in the embodiment, the coating material in the embodiment 2 is accurately weighed and then buried in soil at 58 ℃ +/-2 ℃, a sample is taken after 6 months, the soil on the surface is cleaned, then the vacuum drying is carried out for 24 hours, the weighing is carried out, and the weight loss rate of the sample is calculated to be 31.2%.

Example 3

A production method of sebacic acid byproduct polyester polyol comprises the following steps:

1) firstly, placing 1mol of sebacic acid by-product fatty acid and 1mol of glycerol into a reactor, then heating to 180 ℃ for esterification, preserving the temperature at 180 ℃ for 3 hours, cooling when the acid value is reduced to 1.50mgKOH/g to obtain yellow transparent viscous liquid, namely sebacic acid by-product fatty acid glyceride, and keeping the yellow transparent viscous liquid for subsequent reaction;

2) adding 350g of diethylene glycol, 10g of glycerol, 200g of isophthalic acid, 200g of terephthalic acid and 300g of sebacic acid by-product fatty glyceride obtained in the step 1) into a reaction container, then adding an organic tin catalyst, heating and refluxing for reaction, keeping the temperature at 230 ℃, detecting the acid value, cooling to 190 ℃ after the acid value is reduced to be below 1.63mgKOH/g, starting vacuum rectification, controlling the vacuum degree to be-0.065-0.095 mPa until the acid value of the rectified product is reduced to be below 1.0mgKOH/g and the water mass fraction reaches 0.06%, and cooling and discharging to obtain the polyester polyol.

Secondly, according to GB/T12008.3-2009, the hydroxyl value of the obtained polyester polyol is 207.3mgKOH/g, and the viscosity is 12300CPS/25 ℃ by measuring with a phthalic anhydride method.

Example 4

A method for preparing a polyurethane coated controlled release fertilizer by using the polyester polyol synthesized in example 3 comprises the following steps:

weighing 1 kg of granular urea with the particle size of 2.00-4.75 mm, adding the granular urea into a sugar-coating machine, and heating at 62 ℃; 2.8g of polymeric MDI and 4.2g of polyester polyol are mixed and stirred and then added on the surface of the granular urea, the polyurethane film starts to perform cross-linking reaction on the surface of the granular urea, the viscosity is increased, and a compact and tough polyurethane film is formed after the coating material is gradually cured on the surface of the urea for 3-5 minutes and dispersed, wherein the coating rate is 0.7 percent. This was repeated 3 times, and 2.8g of polymeric MDI and 4.2g of polyester polyol were added for the second and third times, respectively, until the coating rate was 2.1%. And finally, adding paraffin accounting for 0.2 percent of the total mass of the fertilizer to prevent the fertilizer particles from being adhered, and cooling to 20 ℃ to prepare the polyester polyol polyurethane coated urea synthesized by the sebacic acid by-product fatty acid.

Second, testing the controlled release performance of the coated controlled release fertilizer

The specific test method was the same as in example 2.

The nutrient release period of the coated controlled release fertilizer prepared in this example 4 was 60 days.

Example 5

A production method of sebacic acid byproduct polyester polyol comprises the following steps:

1) firstly, 1mol of sebacic acid by-product fatty acid and 1.2mol of glycerol are placed in a reactor, then the reactor is heated to 200 ℃ for esterification, the temperature is kept at 200 ℃ for 4 hours, the temperature is reduced when the acid value is reduced to 1.17mgKOH/g, yellow transparent viscous liquid is obtained, namely sebacic acid by-product fatty acid glyceride, and the yellow transparent viscous liquid is used for subsequent reaction;

2) adding 260g of diethylene glycol, 20g of glycerol, 250g of phthalic acid, 50g of isophthalic acid and 430g of sebacic acid by-product fatty glyceride obtained in the step 1) into a reaction container, then adding a butyl titanate catalyst, heating and refluxing for reaction, keeping the temperature at 240 ℃ and detecting the acid value, cooling to 200 ℃ when the acid value is reduced to be below 1.17mgKOH/g, starting vacuum rectification, controlling the vacuum degree to be-0.065-0.095 mPa until the acid value of the rectified product is reduced to be below 1.0mgKOH/g and the water mass fraction reaches 0.07%, and cooling and discharging to obtain the polyester polyol.

Secondly, according to GB/T12008.3-2009, the hydroxyl value of the obtained polyester polyol is 266.9mgKOH/g, and the viscosity is 2860CPS/25 ℃ by measuring with a phthalic anhydride method.

Example 6

A method for preparing a polyurethane coated controlled release fertilizer by using the polyester polyol synthesized in example 5 comprises the following steps:

weighing 1 kg of granular urea with the particle size of 2.00-4.75 mm, adding the granular urea into a sugar-coating machine, and heating at 62 ℃; 3.6g of polymeric MDI and 5.4g of polyester polyol are mixed and stirred and then added on the surface of the granular urea, the polyurethane film starts to perform cross-linking reaction on the surface of the granular urea, the viscosity is increased, and a compact and tough polyurethane film is formed after the coating material is gradually solidified on the surface of the urea for 3-5 minutes and dispersed, wherein the coating rate is 0.9 percent. 3.2g of polymeric MDI and 4.8g of polyester polyol were added for the second and third times, respectively, with a coating rate of 0.8% and a final coating rate of 2.5%. And finally, adding paraffin accounting for 0.2 percent of the total mass of the fertilizer to prevent the fertilizer particles from being adhered, and cooling to 20 ℃ to prepare the polyester polyol polyurethane coated urea synthesized by the sebacic acid by-product fatty acid.

Second, testing the controlled release performance of the coated controlled release fertilizer

The specific test method was the same as in example 2.

The nutrient release period of the coated controlled release fertilizer prepared in this example 6 was 90 days.

Example 7

A production method of sebacic acid byproduct polyester polyol comprises the following steps:

1) firstly, 1mol of sebacic acid by-product fatty acid and 1.2mol of glycerol are placed in a reactor, then the reactor is heated to 220 ℃ for esterification, the temperature is kept at 220 ℃ for 4 hours, the temperature is reduced when the acid value is reduced to 0.98mgKOH/g, yellow transparent viscous liquid is obtained, namely sebacic acid by-product fatty acid glyceride, and the yellow transparent viscous liquid is used for subsequent reaction;

2) adding 300g of diethylene glycol, 50g of glycerol, 200g of phthalic acid, 100g of terephthalic acid and 430g of sebacic acid by-product fatty glyceride obtained in the step 1) into a reaction container, then adding a calcium oxide catalyst, heating for reflux reaction, keeping the temperature at 250 ℃ and detecting the acid value, cooling to 210 ℃ when the acid value is reduced to be below 0.98mgKOH/g, starting vacuum rectification, controlling the vacuum degree to be-0.065-0.095 mPa until the acid value of the rectified product is reduced to be below 1.0mgKOH/g and the water mass fraction reaches 0.06%, and cooling and discharging to obtain the polyester polyol.

Secondly, according to GB/T12008.3-2009, the hydroxyl value of the obtained polyester polyol is 347.6mgKOH/g, and the viscosity is 1760CPS/25 ℃ by measuring with a phthalic anhydride method.

Example 8

A method for preparing a polyurethane coated controlled release fertilizer using the polyester polyol synthesized in example 7, comprising the steps of:

weighing 1 kg of granular urea with the particle size of 2.00-4.75 mm, adding the granular urea into a sugar-coating machine, and heating at 65 ℃; 3.2g of polymeric MDI and 4.8g of polyester polyol are mixed and stirred and then added on the surface of the granular urea, the polyurethane film starts to perform cross-linking reaction on the surface of the granular urea, the viscosity is increased, and a compact and tough polyurethane film is formed after the coating material is gradually cured on the surface of the urea for 3-5 minutes and dispersed, wherein the coating rate is 0.8 percent. Then 3.2g of polymeric MDI and 4.8g of polyester polyol were added a second time, with a coating rate of 0.8%. 3.6g of polymeric MDI and 5.4g of polyester polyol are added for the third time, the coating rate is 0.9 percent, and the final coating rate reaches 2.5 percent. And finally, adding paraffin accounting for 0.2 percent of the total mass of the fertilizer to prevent the fertilizer particles from being adhered, and cooling to 20 ℃ to prepare the polyester polyol polyurethane coated urea synthesized by the sebacic acid by-product fatty acid.

Second, testing the controlled release performance of the coated controlled release fertilizer

The specific test method was the same as in example 2.

The nutrient release period of the coated controlled release fertilizer prepared in this example 8 was 90 days.

Example 9

A production method of sebacic acid byproduct polyester polyol comprises the following steps:

1) firstly, putting 1mol of sebacic acid by-product fatty acid and 1.5mol of glycerol into a reactor, heating to 240 ℃, carrying out esterification reaction, preserving the temperature for 5 hours at 240 ℃, cooling when the acid value is reduced to 1.24mgKOH/g, obtaining yellow transparent viscous liquid, namely sebacic acid by-product fatty acid glyceride, and reserving the yellow transparent viscous liquid for subsequent reaction;

2) 200g of diethylene glycol, 20g of glycerol, 200g of phthalic acid, 100g of terephthalic acid and 500g of sebacic acid by-product fatty glyceride obtained in the step 1) are added into a reaction container, then a zinc acetate catalyst is added for heating reflux reaction, the temperature is kept at 260 ℃ and the acid value is detected, when the acid value is reduced to be below 1.24mgKOH/g, the temperature is reduced to 220 ℃, vacuum rectification is started, the vacuum degree is controlled to be-0.065 to-0.095 mPa, the temperature is reduced and discharged when the acid value of the rectified product is reduced to be below 1.0mgKOH/g and the mass fraction of water reaches 0.05%, and then the polyester polyol is obtained.

Secondly, according to GB/T12008.3-2009, the hydroxyl value of the obtained polyester polyol is 277.5mgKOH/g, and the viscosity is 3530CPS/25 ℃ by measuring with a phthalic anhydride method.

Example 10

A method for preparing a polyurethane coated controlled release fertilizer using the polyester polyol synthesized in example 9, comprising the steps of:

weighing 1 kg of granular urea with the particle size of 2.00-4.75 mm, adding the granular urea into a sugar-coating machine, and heating at 65 ℃; 2.8g of polymeric MDI and 4.2g of polyester polyol are mixed and stirred and then added on the surface of the granular urea, the polyurethane film starts to perform cross-linking reaction on the surface of the granular urea, the viscosity is increased, and a compact and tough polyurethane film is formed after the coating material is gradually cured on the surface of the urea for 3-5 minutes and dispersed, wherein the coating rate is 1.0%. This was repeated 3 times, and 4g of polymeric MDI and 6g of polyester polyol were added for the second and third times, respectively, until the coating rate was 3.0%. And finally, adding paraffin accounting for 0.2 percent of the total mass of the fertilizer to prevent the fertilizer particles from being adhered, and cooling to 20 ℃ to prepare the polyester polyol polyurethane coated urea synthesized by the sebacic acid by-product fatty acid.

Second, testing the controlled release performance of the coated controlled release fertilizer

The specific test method was the same as in example 2.

The nutrient release period of the coated controlled release fertilizer prepared in this example 10 was 120 days.

Example 11

A production method of sebacic acid byproduct polyester polyol comprises the following steps:

1) firstly, putting 1mol of sebacic acid by-product fatty acid and 1.5mol of glycerol into a reactor, heating to 200 ℃, carrying out esterification reaction, keeping the temperature at 200 ℃ for 5 hours, cooling when the acid value is reduced to 1.04mgKOH/g, obtaining yellow transparent viscous liquid, namely sebacic acid by-product fatty glyceride, and keeping the yellow transparent viscous liquid for subsequent reaction;

2) 200g of diethylene glycol, 30g of glycerol, 300g of phthalic acid, 56g of isophthalic acid and 350g of sebacic acid by-product fatty glyceride obtained in the step 1) are added into a reaction container, then an organic tin catalyst is added for heating reflux reaction, the temperature is kept at 240 ℃ and the acid value is detected, when the acid value is reduced to be lower than 1.04mgKOH/g, the temperature is reduced to 200 ℃, vacuum rectification is started, the vacuum degree is controlled to be-0.065 to-0.095 mPa, the temperature is reduced until the acid value of the rectified product is reduced to be lower than 1.0mgKOH/g and the water mass fraction reaches 0.07%, and then the polyester polyol is obtained by discharging the temperature reduction.

Secondly, according to GB/T12008.3-2009, the hydroxyl value of the obtained polyester polyol is 181.4mgKOH/g, and the viscosity is 23500CPS/25 ℃ by using a phthalic anhydride method for measurement.

Example 12

A method for preparing a polyurethane coated controlled release fertilizer using the polyester polyol synthesized in example 11, comprising the steps of:

weighing 1 kg of granular urea with the particle size of 2.00-4.75 mm, adding the granular urea into a sugar-coating machine, and heating at 68 ℃; 4.4g of polymeric MDI and 6.6g of polyester polyol are mixed and stirred and then added on the surface of the granular urea, the polyurethane film is subjected to cross-linking reaction on the surface of the granular urea, the viscosity is increased, and a compact and tough polyurethane film is formed after the coating material is gradually cured on the surface of the urea for 3-5 minutes and dispersed, wherein the coating rate is 1.1%. 4.8g of polymeric MDI and 7.2g of polyester polyol were added for the second and third times, respectively, until the coating rate was 3.5%. And finally, adding paraffin accounting for 0.2 percent of the total mass of the fertilizer to prevent the fertilizer particles from being adhered, and cooling to 20 ℃ to prepare the polyester polyol polyurethane coated urea synthesized by the sebacic acid by-product fatty acid.

Second, testing the controlled release performance of the coated controlled release fertilizer

The specific test method was the same as in example 2.

The coated controlled release fertilizer prepared in this example 12 had a nutrient release period of 150 days.

Application examples

Firstly, sampling: coated controlled release fertilizers prepared in example 2, example 4, example 6, example 8, example 10, example 12;

secondly, testing the nutrient release period of the coated controlled release fertilizer prepared in the examples 2, 4, 6, 8, 10 and 12 by using a hydrostatic leaching method at 25 ℃, sampling different days to determine the accumulated release rate of nitrogen in still water, wherein the sampling is performed at 24h, 7d, 28d, 56d, 60d, 90d, 120d and 150d, and finally recording the accumulated release rate of the coated urea in the examples in the hydrostatic leaching process, which is specifically shown in the following table 1.

Table 1: data for measuring nitrogen cumulative release rate of film-coated urea in hydrostatic leaching in different experimental examples

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.