Production method of polyaspartic acid ester resin

Abstract

The invention provides a production method of polyaspartic acid ester resin, and relates to the technical field of polyaspartic acid ester resin production. According to the method, the pre-reaction and the final reaction containing the catalyst are combined, so that the production efficiency of the polyaspartate resin can be greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polyaspartic acid ester resin production and relates to a production method of polyaspartic acid ester resin. Background Art

[0002] Polyaspartic acid resin is the core raw material for preparing aspartic polyurea materials. It is generally obtained through the Michael addition reaction of an organic primary amine (such as 4,4'-diaminodicyclohexylmethane) and a maleate (such as diethyl maleate). This reaction is characterized by a relatively fast initial reaction and a very slow reaction in the later stages. The main reason is that the maleate is converted to fumarate in the later stages of the reaction, and the reactivity of fumarate and organic primary amines is relatively low. Therefore, temperature control is required when the reaction is fast in the early stages, and the reaction rate is very slow after the maleate conversion rate reaches 95%. To improve the conversion rate, the following two methods are generally used: 1. Extending the reaction time, and 2. Excess maleate combined with distillation and purification of the product. Method 1 generally uses an organic diprimary amine and a maleate ester in a molar ratio of 1:2 for reaction. After the reaction reaches a conversion rate of 95% for the maleate ester (generally requiring 120-150 hours), a long period of heat preservation is required to further increase the conversion rate and solid content. For example, it generally takes 3-6 months to increase the conversion rate from 97% to 98% at room temperature, and it generally takes half a year or even longer to increase it to 99%, resulting in very low production efficiency. Method 2 can increase the conversion rate of the organic amine to over 98% and the solid content to over 95% in a relatively short period of time (e.g., 48-72 hours), and then remove the unreacted organic diprimary amine and maleate ester using a thin film evaporator combined with a short-path evaporator. This method has the advantages of high efficiency and stable quality, but also has the disadvantages of large equipment investment, long processing flow, high energy consumption, and the generation of waste liquid and waste gas.

[0003] Therefore, the existing production method of polyaspartic acid ester resin is in urgent need of improvement. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a production method of polyaspartic acid ester resin.

[0005] The technical solutions of the present invention are as follows:

[0006] A continuous production method for polyaspartic acid ester resin comprises the following steps:

[0007] The organic amine compound and the maleate are pre-reacted to obtain a pre-reaction product;

[0008] The pre-reaction product is subjected to a final reaction in the presence of a catalyst to obtain the polyaspartic acid ester resin;

[0009] The catalyst is selected from acidic cation exchange resin or basic anion exchange resin.

[0010] Preferably, the number of primary amino groups in the organic amine compound is n, and the molar ratio of the organic amine compound to the maleate is 1:n, where n=2-4.

[0011] More preferably, the organic amine compound is a diprimary amine compound.

[0012] More preferably, the structure of the diprimary amine compound is as shown in the following formula (1):

[0013] NH2R 1 NH2(1)

[0014] Among them, R 1 One or a combination of two or more selected from the group consisting of C2-C18 alkyl, hybridized C2-C18 alkyl, C6-C20 cycloalkyl-containing hydrocarbon group, C6-C20 aromatic group and polyether segment.

[0015] Preferably, the maleate is selected from one or a combination of two or more of diethyl maleate, dimethyl maleate, dibutyl maleate, dipropyl maleate, diisopropyl maleate, dihexyl maleate, diisooctyl maleate and dioctyl maleate.

[0016] Preferably, the temperature of the pre-reaction is 40-80° C., and the reaction time is 1-10 h.

[0017] Preferably, the conversion rate of the maleate in the pre-reaction product is not less than 80%.

[0018] Preferably, the temperature of the final reaction does not exceed 100°C.

[0019] Preferably, the total time of the preliminary reaction and the final reaction does not exceed 72 hours, and the conversion rate of the maleate after the final reaction is completed is not less than 98%.

[0020] Preferably, the final reaction is carried out in a fixed bed reaction apparatus;

[0021] The fixed bed reaction device is equipped with a material circulation device to promote heat and mass exchange of the reaction materials in the fixed bed reaction device.

[0022] The beneficial effects of the present invention are:

[0023] (1) The present invention adopts a method of pre-reaction combined with catalyst final reaction to prepare polyaspartic acid ester resin. In the final reaction stage, acidic cation exchange resin or basic anion exchange resin is used as a catalyst. Polyaspartic acid ester resin with a high yield can be obtained in a shorter time, thereby improving the reaction efficiency.

[0024] (2) The method of the present invention is suitable for using organic amine compounds containing one or more primary amino groups and has wide applicability. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0026] The present invention provides a continuous production method of polyaspartic acid ester resin, comprising the following steps:

[0027] The organic amine compound and the maleate are pre-reacted to obtain a pre-reaction product;

[0028] The pre-reaction product is subjected to a final reaction in the presence of a catalyst to obtain a polyaspartic acid ester resin;

[0029] The catalyst is selected from acidic cation exchange resin or basic anion exchange resin.

[0030] The present invention utilizes a pre-reaction combined with a catalyst-catalyzed final reaction. The pre-reaction stage is a rapid reaction stage, during which most of the organic amine compound and maleate react. In the pre-reaction product, most or all of the unreacted maleate is converted into a fumarate with low reactivity. The final reaction is then carried out. Using an acidic cation exchange resin or a basic anion exchange resin as a catalyst, the reaction rate of the organic amine compound and fumarate is increased, allowing the final reaction to be completed in a relatively short period of time. Therefore, the present invention can achieve a maleate (including fumarate) conversion rate of 98% or greater with a total reaction time (the sum of the pre-reaction time and the final reaction time) of no more than 72 hours. In the present invention, the acidic cation exchange resin or the basic anion exchange resin as a catalyst has a long catalytic life, allowing continuous production for one year without the need for catalyst replacement. There are no particular restrictions on the acidic cation exchange resin and the basic anion exchange resin, and they can be directly obtained commercially. The acidic cation exchange resin can be a strong acid cation exchange resin or a weak acid cation exchange resin, such as type 732 resin, type 0017 resin, type 724 resin, type 725 resin, etc.; the basic anion exchange resin can be a strong basic anion exchange resin or a weak basic anion exchange resin, such as 201x7, IRA900, AGMP-1M, D301 resin, No. 704, No. 717, etc.

[0031] In some embodiments, the number of primary amino groups in the organic amine compound is n, and the molar ratio of the organic amine compound to the maleate is 1:n, where n=2-4.

[0032] In the present invention, the organic amine compound can be a divalent primary amine compound (n=2) or a divalent or higher polyvalent primary amine compound (n=3-4), such as cyclohexylamine, 2-methylcyclohexylamine, 4-methylcyclohexylamine, 2-methylcyclopentylamine, 4,4'-diaminodicyclohexylmethane PACM, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, polyetheramine (D2000, T403, etc.), or a combination of multiple organic amine compounds. The production method of the polyaspartic acid ester resin of the present invention has high reaction efficiency, the molar ratio of the organic amine compound and the maleate is equal, and the conversion rate of maleate (including fumarate) can reach 98% or more within the entire reaction time of no more than 72 hours, thereby achieving a high solid content of the product. The obtained polyaspartic acid ester resin has a high purity (purity ≥98%) and does not require additional treatment or purification steps. There is no particular limitation on the method for testing the conversion rate of maleate (including fumarate), which can be determined by measuring the solid content or by high performance liquid chromatography (HPLC).

[0033] In some embodiments, the organic amine compound is a diprimary amine compound, the structure of which is shown in the following formula (1):

[0034] NH2R 1 NH2(1)

[0035] Among them, R 1 One or a combination of two or more selected from the group consisting of C2-C18 alkyl, hybridized C2-C18 alkyl, C6-C20 cycloalkyl-containing hydrocarbon, C6-C20 aromatic group, and polyether segment; specifically, the diprimary amine compound may be 4,4'-diaminodicyclohexylmethane PACM, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane DMDC, 1,4-cyclohexanediamine, polyetheramine (such as D2000, T403), etc.;

[0036] The structure of maleate is shown in the following formula (2):

[0037] R 2 OOCCH=CHCOOR 3 (2)

[0038] Among them, R 2 and R 3 Individually selected from C1-C8 alkyl; specifically, the maleate can be selected from one or a combination of two or more of diethyl maleate, dimethyl maleate, dibutyl maleate, dipropyl maleate, diisopropyl maleate, dihexyl maleate, diisooctyl maleate and dioctyl maleate.

[0039] In some embodiments, the temperature of the pre-reaction is 40-80°C, and the reaction time is 1-10h. Specifically, the temperature of the pre-reaction can be any value among 40°C, 50°C, 60°C, 70°C, 80°C, etc. or any value therebetween, and the time of the pre-reaction can be any value among 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, etc. or any value therebetween. The higher the pre-reaction temperature, the shorter the pre-reaction time can be. For the pre-reaction between the organic amine compound and the maleate, the reaction is an exothermic reaction. In order to avoid excessive heat release, the method of adding maleate dropwise to the organic amine compound can be used to control the heat release rate and the reaction temperature. When necessary, the temperature can be controlled by passing cooling water through the reactor of the pre-reaction.

[0040] In some embodiments, the conversion rate of maleate (including fumarate) in the pre-reaction product is not less than 80%. The reaction rate of the organic amine compound and the maleate in the pre-reaction stage is relatively fast, and the conversion rate of the organic amine compound is relatively high. For example, the conversion rate of the organic amine compound in the pre-reaction product can be any value among 80%, 82%, 85%, 86%, 88%, 90%, etc., or any value in between.

[0041] In some embodiments, the final reaction temperature does not exceed 100° C. to avoid damage to the catalyst caused by excessively high temperatures, or to reduce catalyst activity and shortened catalyst life. The final reaction time can be determined based on the conversion rate of maleate (including fumarate) in the pre-reaction product, the final reaction temperature, the catalyst activity, and the like.

[0042] In some embodiments, the combined duration of the pre-reaction and the final reaction is no more than 72 hours, and the conversion rate of the maleate (including fumarate) after the final reaction is completed is no less than 98%. The continuous production method of the polyaspartic acid ester resin of the present invention, with a maleate (including fumarate) conversion rate of no less than 98% as the reaction endpoint, and the combined duration of the pre-reaction and the final reaction no more than 72 hours, significantly shortens the preparation cycle compared to existing technologies, improves production efficiency, and uses relatively simple equipment.

[0043] In some embodiments, the final reaction is carried out in a fixed bed reaction device; the catalyst is fixed in the fixed bed reaction device, which is a commonly used reaction device;

[0044] The fixed bed reaction device is equipped with a material circulation device to promote heat and mass exchange of the reaction materials in the fixed bed reaction device and improve production efficiency.

[0045] The technical solution of the present invention is further described and illustrated below based on various embodiments.

[0046] Example 1

[0047] The molar ratio of 4,4'-diaminodicyclohexylmethane PACM and diethyl maleate is 1:2.

[0048] PACM was added to the reactor, and diethyl maleate was added dropwise. The temperature in the reaction system was maintained at 70-80°C by controlling the addition rate and cooling water. The addition was completed over 4 hours to obtain a pre-reaction product. The conversion rate of diethyl maleate in the pre-reaction product was measured to be 88.7%.

[0049] The pre-reaction product was transferred through a pipeline to a fixed-bed reaction device equipped with a strongly acidic cation exchange resin for final reaction. The final reaction temperature was 80° C. After 60 hours of reaction, the final reaction product was collected at the discharge port. The conversion rate of diethyl maleate (including diethyl fumarate) in the final reaction product was measured to be 98.2%.

[0050] In this embodiment, the pre-reaction time and the final reaction time are 64 hours in total. The final reaction product can be used directly without further purification.

[0051] Comparative Example 1

[0052] This comparative example differs from Example 1 in that the fixed-bed reactor in Example 1 was not equipped with a strongly acidic cation exchange resin, meaning that the final reaction in this comparative example lacked a catalyst. The remaining steps remained unchanged. The final reaction temperature was 80°C, and the final reaction product was collected at the discharge port after 60 hours of reaction. The conversion of diethyl maleate (including diethyl fumarate) in the final reaction product was measured to be 95.2%.

[0053] Comparative Example 2

[0054] The difference between this comparative example and comparative example 1 is that in comparative example 1, the final reaction time was increased from 60 hours to 90 hours. The remaining steps remained unchanged. The conversion rate of diethyl maleate (including diethyl fumarate) in the final reaction product was measured to be 96.4%.

[0055] Comparative Example 3

[0056] The molar ratio of PACM and diethyl maleate was 1:2.

[0057] PACM and diethyl maleate were separately transferred via pipelines to a fixed-bed reactor containing a strongly acidic cation exchange resin for reaction. The feed rate was controlled to maintain a temperature of 70-80°C in the fixed-bed reactor. After 64 hours of reaction, the final reaction product was collected at the discharge port. The conversion rate of diethyl maleate (including diethyl fumarate) in the reaction product was measured to be 95.7%.

[0058] Comparative Example 4

[0059] The difference between this comparative example and comparative example 3 is that in comparative example 3, the reaction time was increased from 64 h to 144 h. The remaining steps remained unchanged. The conversion rate of diethyl maleate (including diethyl fumarate) in the final reaction product was measured to be 98.2%.

[0060] Therefore, it can be seen from Comparative Examples 3 and 4 that if the reaction raw materials are directly reacted in a fixed bed reactor without pre-reaction, the reaction efficiency is not high. The possible reason is that due to the presence of the catalyst, diethyl maleate is quickly converted into diethyl fumarate, and the reactivity of diethyl fumarate is significantly lower than that of diethyl maleate, resulting in a significantly longer reaction time and reduced production efficiency.

[0061] Example 2

[0062] The pre-reaction product in Example 1 was transferred through a pipeline to a stirred reactor containing a strong acidic cation exchange resin for final reaction. The weight of the strong acidic cation exchange resin was 1% of the weight of the pre-reaction product. The final reaction temperature was 80° C. After 66 hours of reaction, the product was filtered and discharged to obtain a final reaction product. The conversion rate of diethyl maleate (including diethyl fumarate) in the final reaction product was measured to be 98.0%.

[0063] In this embodiment, the pre-reaction time and the final reaction time are 70 hours in total. The final reaction product can be used directly without further purification.

[0064] Example 3

[0065] The molar ratio of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane DMDC and diethyl maleate is 1:2.

[0066] DMDC was added to the reactor, and diethyl maleate was added dropwise. The temperature in the reaction system was maintained at 60-70°C by controlling the addition rate and cooling water. The addition was completed over 9 hours to obtain a pre-reaction product. The conversion rate of diethyl maleate (including diethyl fumarate) in the pre-reaction product was measured to be 83.0%.

[0067] The pre-reaction product was transferred through a pipeline to a fixed-bed reaction apparatus equipped with a strong alkaline anion exchange resin for final reaction. The final reaction temperature was 90° C. After 62 hours of reaction, the final reaction product was collected at the discharge port. The conversion rate of diethyl maleate (including diethyl fumarate) in the final reaction product was measured to be 98.0%.

[0068] In this embodiment, the pre-reaction time and the final reaction time are 71 hours in total. The final reaction product can be used directly without further purification.

[0069] Example 4

[0070] The molar ratio of polyetheramine T403 and diethyl maleate is 1:3.

[0071] T403 was added to the reactor, and diethyl maleate was added dropwise. The temperature in the reaction system was maintained at 50-60°C by controlling the addition rate and cooling water. The addition was completed over 6 hours to obtain a pre-reaction product. The conversion rate of diethyl maleate (including diethyl fumarate) in the pre-reaction product was measured to be 86.2%.

[0072] The pre-reaction product was transferred through a pipeline to a fixed-bed reaction apparatus equipped with a strongly acidic cation exchange resin for final reaction. The final reaction temperature was 90° C. After 53 hours of reaction, the final reaction product was collected at the discharge port. The conversion rate of diethyl maleate (including diethyl fumarate) in the final reaction product was measured to be 98.1%.

[0073] In this embodiment, the pre-reaction time and the final reaction time are 59 hours in total. The final reaction product can be used directly without further purification.

[0074] Example 5

[0075] This Example differs from Example 4 in that, in Example 4, a material circulation device was installed on the fixed-bed reactor to circulate the reaction materials within the fixed-bed reactor. The final reaction temperature was 90°C, and the final reaction product was collected at the discharge port after 46 hours of reaction. The conversion rate of diethyl maleate (including diethyl fumarate) in the final reaction product was measured to be 98.0%.

[0076] In this embodiment, the pre-reaction time and the final reaction time are 52 hours in total. The final reaction product can be used directly without further purification.

[0077] As described above, the basic principles, main features, and advantages of the present invention are shown and described. Those skilled in the art should understand that the present invention is not limited to the above-described embodiments. The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. In other words, equivalent changes and modifications made within the scope of the present invention and the contents of the specification should still fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing a polyaspartic acid ester resin, characterized in that the steps include: The organic amine compound and the maleate are pre-reacted to obtain a pre-reaction product; The pre-reaction product is subjected to a final reaction in the presence of a catalyst to obtain the polyaspartic acid ester resin; The catalyst is selected from acidic cation exchange resin or basic anion exchange resin.

2. The method for producing a polyaspartic acid ester resin according to claim 1, wherein The number of primary amino groups in the organic amine compound is n, and the molar ratio of the organic amine compound to the maleate is 1:n, where n=2-4.

3. The production method of polyaspartic acid ester resin according to claim 2, characterized in that, The organic amine compound is a diprimary amine compound.

4. The method for producing a polyaspartic acid ester resin according to claim 3, wherein The structure of the dibasic primary amine compound is shown in the following formula (1): NH2R 1 NH2(1) Among them, R 1 One or a combination of two or more selected from the group consisting of C2-C18 alkyl, hybridized C2-C18 alkyl, C6-C20 cycloalkyl-containing hydrocarbon group, C6-C20 aromatic group and polyether segment.

5. The method for producing a polyaspartic acid ester resin according to claim 1, wherein The maleate is selected from one or a combination of two or more of diethyl maleate, dimethyl maleate, dibutyl maleate, dipropyl maleate, diisopropyl maleate, dihexyl maleate, diisooctyl maleate and dioctyl maleate.

6. The method for producing a polyaspartic acid ester resin according to claim 1, wherein The temperature of the preliminary reaction is 40-80° C., and the reaction time is 1-10 h.

7. The method for producing a polyaspartic acid ester resin according to claim 1, wherein The conversion rate of the maleate in the pre-reaction product is not less than 80%.

8. The method for producing a polyaspartic acid ester resin according to claim 1, wherein The temperature of the final reaction does not exceed 100°C.

9. The method for producing a polyaspartic acid ester resin according to claim 1, wherein The total time of the preliminary reaction and the final reaction is no more than 72 hours, and the conversion rate of the maleate after the final reaction is completed is no less than 98%.

10. The method for producing a polyaspartic acid ester resin according to claim 1, wherein: The final reaction is carried out in a fixed bed reaction device; The fixed bed reaction device is equipped with a material circulation device to promote heat and mass exchange of the reaction materials in the fixed bed reaction device.