Modified polyaspartic acid ester resin as well as preparation method and application thereof

Abstract

The invention relates to the technical field of polyaspartic acid ester resin, in particular to modified polyaspartic acid ester resin as well as a preparation method and application thereof. The modified polyaspartic acid ester resin is prepared from silicon-containing diamine and maleate and has a structural formula shown in a formula (I), R1, R2, R3 and R4 represent alkane groups or silicon-containing oxygen groups, and R5 represents alkyl. The process is simple, an antioxidant does not need to be added, the cost is reduced, industrial production is easy, and the heat resistance, the flexibility and the hydrophobicity of the obtained product are improved; high conversion rate and low residue are realized; the high adhesive force with metal is realized; no solvent is added, and the VOC emission standard is met. (I)

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyaspartic ester resin, in particular to a modified polyaspartic ester resin and a preparation method and application thereof. BACKGROUND

[0002] Polyaspartic ester is an aliphatic compound with secondary amine groups, which has more excellent characteristics than general hydroxyl resin and epoxy resin, such as high weather resistance, high performance, and good environmental protection performance. Polyaspartic ester polyurea coating has high gloss and high adhesion on the surface of the substrate. In addition, polyaspartic ester has small molecular weight and low viscosity, and the coating prepared from polyaspartic ester resin can achieve zero VOC emission.

[0003] Although there are many kinds of anticorrosive coatings, each has its own advantages. However, the molecular weight of the aliphatic isocyanate matched with the commonly used polyaspartic ester resin is small, and the glass transition temperature of the polyaspartic ester polyurea generated after curing is 50-60℃, which causes the polyaspartic ester polyurea to be in a high elastic state instead of a high molecular glass state when the temperature is higher than 60℃. The hardness of the paint film corresponding to the polyaspartic ester polyurea is reduced, and the performance of the paint film at high temperature, such as the resistance to high temperature, the resistance to aging at high temperature, and the resistance to salt spray, is not as good as the performance at low temperature. The water contact angle of the polyaspartic ester polyurea is low, the moisture wettability of the surface of the polyaspartic ester polyurea is high, and the hydrophobicity is poor. In addition, the adhesion of the polyaspartic ester polyurea coating to the metal substrate is low. SUMMARY

[0004] In order to solve the above technical problems in the prior art, the present application provides a modified polyaspartic ester resin and a preparation method and application thereof.

[0005] The technical solution of the present application to solve the above technical problems is as follows: The first aspect of the present application is to provide a modified polyaspartic ester resin prepared from a silicon-containing diamine and maleate, wherein the modified polyaspartic ester resin has a structural formula as shown in formula (I):

[0006] (I); wherein R1, R2, R3, and R4 represent alkyl groups or silicon-containing groups, and R5 represents an alkyl group.

[0007] On the basis of the above technical solution, the present application can also be improved as follows: Further, the silicon-containing diamine is a siloxane type diamine, and the siloxane type diamine has a structural formula as shown in formula (II):

[0008] (II).

[0009] Further, the siloxane type diamine is selected from any one of 4-((tert-butyldimethylsilyl)oxy)benzene-1,2-diamine, bis(4-aminophenoxy)dimethylsilane, polydimethylsiloxane diamine, bis(3-aminophenoxy)dimethylsilane, bis(4-aminophenoxy)tetramethylsiloxane; and the maleate is selected from any one of diethyl maleate, dibutyl maleate.

[0010] Further, the siloxane type diamine and the maleate are reacted under the protection of inert gas at 30-120℃ with the catalyst, and when the conversion rate of the siloxane type diamine is greater than 99mol%, the reaction is stopped, and the unreacted maleate is removed to obtain the modified polyaspartic acid ester resin.

[0011] Further, the catalyst is a mixture of one or more of sodium methoxide, sodium hydroxide, sodium carbonate, sodium ethoxide, and azole.

[0012] Further, the molar ratio of the siloxane type diamine and the maleate is 1:(2-8), and the catalyst accounts for 0.3-0.5wt% of the total mass of the siloxane type diamine and the maleate.

[0013] The second aspect of the present application provides a preparation method of the modified polyaspartic acid ester resin, comprising the following steps: S1, adding raw materials or components of raw materials in sequence into a reaction container, and stirring and heating under the condition of inert gas; S2, heating to make the amine value ≤40mgKOH / g; S3, heating to make the amine value ≤5mgKOH / g; S4, starting the vacuum heating of the thin film evaporator to remove the maleate, and raising the vacuum degree to -0.10MPa~ -0.05MPa, and when the solid content of the product is ≥97±2% and the amine value is ≤3mgKOH / g, the product can be discharged after cooling.

[0014] Further, in step S4, the heating temperature is 100-180℃, and the feeding flow rate is 10-30mg / min.

[0015] Further, in step S3, the heating temperature is 80-120℃, and the reaction time is 30-40 hours, and the obtained product is a transparent light yellow liquid, and the viscosity of the obtained product at 25℃ is 2000-10000cps.

[0016] Further, in step S2, the heating temperature is 30-50℃, the reaction time is 10-20 hours, and the heating rate is 2-5℃ / min.

[0017] Another aspect of the present application is to provide a polyaspartic ester polyurea coating prepared from the modified polyaspartic ester resin.

[0018] Compared with the prior art, the present application has the following technical effects: The present application has the advantages of simple process, no need to add antioxidants, reduced cost, easy industrial production, improved heat resistance, flexibility and hydrophobicity of the obtained product, high conversion rate and low residual characteristics, significantly improved adhesion to metal, no solvent addition, and compliance with VOC emission standards. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Gel permeation chromatogram of the polyaspartic ester resin product of Example 1 of the present application; Figure 2 Gel permeation chromatogram of the polyaspartic ester resin product of Example 3 of the present application. DETAILED DESCRIPTION

[0020] The following describes the embodiments of the present application by specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. Although the description of the present application will be introduced in combination with the preferred embodiments, this does not mean that the features of the present application are limited to the embodiments. On the contrary, the purpose of introducing the application in combination with the embodiments is to cover other options or modifications that can be extended based on the claims of the present application. In order to provide a deep understanding of the present application, many specific details will be included in the following description. The present application can also be implemented without using these details. In addition, in order to avoid confusion or obscure the focus of the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0021] Example 1 The present embodiment provides a method for preparing a polyaspartic ester resin, which is specifically as follows: S1, 516g of diethyl maleate, 224g of 4-((tert-butyldimethylsilyl)oxy)benzene-1,2-diamine, 3g of sodium methoxide were sequentially added into a 1000 mL four-necked flask, nitrogen was introduced, and stirring was started; S2, heating was started, the temperature was increased to 50℃ at a rate of 5℃ / min, and the reaction was kept for 15 hours, and the amine value was 37.5mgKOH / g; S3, the temperature was increased to 100℃ at a rate of 5℃ / min, and the reaction was kept for 35 hours, and the amine value was 4.2mgKOH / g; S4, start the thin film evaporator, vacuum heating to 150℃, the feed flow rate is 15 mg / min, remove diethyl maleate, so that the vacuum degree rises to -0.10 MPa~ -0.05 MPa, until the product solid content is 97.4%, amine value is 2.7 mgKOH / g, cooling and discharging to obtain the polyaspartic ester resin product, its gel permeation chromatogram (GPC chart) is shown in Figure 1 , wherein the main peak (the peak between 17.5 min and 19.3 min) is the polyaspartic ester resin product peak, and the three curves represent three GPC tests; the product is a light yellow liquid, the color value is 72 degrees, and the viscosity at 25℃ is 6350 cps.

[0022] Example 2 The embodiment provides a method for preparing a polyaspartic ester resin, and specifically as follows: S1, in a 1000 mL four-necked flask, 684 g of dibutyl maleate, 224 g of 4- ((tert-butyldimethylsilyl) oxy) benzene-1,2-diamine, and 3 g of sodium ethoxide are sequentially added, nitrogen is introduced, and stirring is started; S2, start heating, and increase the temperature to 50℃ at a rate of 5℃ / min, and keep the temperature for 16 hours, and the amine value is 36.4 mgKOH / g; S3, increase the temperature to 100℃ at a rate of 7℃ / min, and keep the temperature for 32 hours, and the amine value is 4.7 mgKOH / g; S4, start the thin film evaporator, vacuum heating to 160℃, the feed flow rate is 25 mg / min, remove diethyl maleate, so that the vacuum degree rises to -0.10 MPa~ -0.05 MPa, until the product solid content is 98.2%, amine value is 2.4 mgKOH / g, cooling and discharging to obtain the polyaspartic ester resin product, the product is a light yellow liquid, the color value is 91 degrees, and the viscosity at 25℃ is 6827 cps.

[0023] Example 3 The embodiment provides a method for preparing a polyaspartic ester resin, and specifically as follows: S1, in a 2000 mL four-necked flask, 1376 g of diethyl maleate, 275 g of bis (4-aminophenoxy) dimethylsilane, and 6 g of sodium ethoxide are sequentially added, nitrogen is introduced, and stirring is started; S2, start heating, and increase the temperature to 30℃ at a rate of 5℃ / min, and keep the temperature for 20 hours, and the amine value is 36.4 mgKOH / g; S3, increase the temperature to 120℃ at a rate of 10℃ / min, and keep the temperature for 30 hours, and the amine value is 3.8 mgKOH / g; S4, start the thin film evaporator, vacuum heating to 150℃, the flow rate is 30mg / min, remove the diethyl maleate, so that the vacuum degree rises to -0.10MPa~ -0.05MPa, until the product solid content is 96.4%, amine value is 2.6mgKOH / g, cooling discharge to obtain polyaspartic ester resin product, the gel permeation chromatogram (GPC chart) is shown in Figure 2 , wherein the main peak (peak between 18.4min and 20.2min) is the polyaspartic ester resin product peak, and the two curves represent two GPC tests; the product is a light yellow liquid, the color value is 62 degrees, and the viscosity at 25℃ is 6671cps.

[0024] Example 4 The embodiment provides a method for preparing polyaspartic ester resin, which specifically comprises the following steps: S1, in a 2000ml four-necked flask, sequentially add 1824g of dibutyl maleate, 275g of bis (4-aminophenoxy) dimethylsilane, 8g of sodium hydroxide, and introduce nitrogen, and start stirring; S2, start heating, and increase the temperature to 30℃ at a rate of 5℃ / min, and keep the temperature for 20 hours, and measure the amine value to be 35.7mgKOH / g; S3, increase the temperature to 120℃ at a rate of 10℃ / min, and keep the temperature for 30 hours, and the amine value is 3.7mgKOH / g; S4, start the thin film evaporator, vacuum heating to 150℃, the flow rate is 30mg / min, remove the diethyl maleate, so that the vacuum degree rises to -0.10MPa~ -0.05MPa, until the product solid content is 96.4%, amine value is 2.6mgKOH / g, cooling discharge to obtain polyaspartic ester resin product, the product is a light yellow liquid, the color value is 62 degrees, and the viscosity at 25℃ is 6350cps.

[0025] Example 5 The embodiment provides a method for preparing polyaspartic ester resin, which specifically comprises the following steps: S1, in a 2000ml four-necked flask, sequentially add 1824g of dibutyl maleate, 275g of bis (4-aminophenoxy) dimethylsilane, 8g of sodium hydroxide, and introduce nitrogen, and start stirring; S2, start heating, and increase the temperature to 30℃ at a rate of 5℃ / min, and keep the temperature for 20 hours, and measure the amine value to be 35.7mgKOH / g; S3, increase the temperature to 120℃ at a rate of 10℃ / min, and keep the temperature for 30 hours, and the amine value is 3.7mgKOH / g; S4, start the film evaporator, vacuum heating to 180℃, the feed flow rate is 30mg / min, remove dibutyl maleate, so that the vacuum rises to-0.10MPa~ -0.05MPa, until the product solid content is 98.4%, amine value is 2.82mgKOH / g, cooling discharge to obtain polyaspartic ester resin product, the product is a light yellow liquid, color value is 81 degrees, the viscosity at 25℃ is 7311 cps.

[0026] Example 6 The present embodiment provides a method for preparing polyaspartic ester resin, as follows: S1, in a 2000 mL four-necked flask, add 1140g dibutyl maleate, add 348.5g bis(4-aminophenoxy)tetramethylsiloxane, 6g sodium hydroxide, nitrogen is introduced, and stirring is started; S2, start heating, temperature is raised to 50℃ at 5℃ / min, and keep the temperature for 10 hours, the amine value is 31.4mgKOH / g; S3, temperature is raised to 120℃ at 10℃ / min, and keep the temperature for 30 hours, the amine value is 4.6mgKOH / g; S4, start the film evaporator, vacuum heating to 180℃, the feed flow rate is 30mg / min, remove dibutyl maleate, so that the vacuum rises to-0.10MPa~ -0.05MPa, until the product solid content is 99.3%, amine value is 2.9mgKOH / g, cooling discharge to obtain polyaspartic ester resin product, the product is a light yellow liquid, color value is 87 degrees, the viscosity at 25℃ is 9211 cps.

[0027] Comparative Example 1 The polyaspartic ester resin NH1420 commonly used in the market is used, and the structure is as follows: .

[0028] Comparative Example 2 The polyaspartic ester resin NH1520 commonly used in the market is used, and the structure is as follows: .

[0029] Performance test Resin NH1420 of Comparative Example 1, resin NH1520 of Comparative Example 2, 100 parts each, leveling agent BYK381 0.5 parts, silicone defoaming agent QX-10S 0.3 parts, adhesion promoter TEGO Add Bond LTW 3 parts were added to obtain component A, component B was TDI curing agent, the amount of TDI curing agent was controlled so that n(NCO):n(active hydrogen)=1.2:1.8, and the polyaspartic ester polyurea was obtained by reaction of component A and component B.

[0030] The obtained polyaspartic ester polyurea was characterized in terms of tensile strength, water impermeability, adhesion, impact resistance, and paint film water resistance, wherein the test methods for gel time, elongation, tensile strength, and water impermeability were GB / T 5210-2006 "Color Paint and Varnish Pull-off Adhesion Test"; the test method for impact resistance was GB / T 1732-1993 "Paint Film Impact Resistance Test"; and the test method for paint film water resistance was GB / T 1733-1993 "Paint Film Water Resistance Test".

[0031] The test results are shown in Table 1.

[0032] Table 1 Performance test results of polyaspartic ester polyurea coatings prepared using polyaspartic ester resins of Examples 1-6 and Comparative Examples 1-2

[0033] As can be seen from Table 1, the polyureas of Examples 1-6 of the present application all have excellent water resistance and strong adhesion, and in addition, the weather resistance of the inventive structure containing a silicone polyaspartic ester resin is significantly improved.

[0034] The above description is merely preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A modified polyaspartic acid ester resin, characterized in that, The modified polyaspartic acid ester resin, prepared by reacting silanediamine with maleic ester, has the structural formula shown in formula (I): （I）； In this context, R1, R2, R3, and R4 represent alkane groups or siloxane groups, and R5 represents an alkyl group.

2. The modified polyaspartic acid ester resin according to claim 1, characterized in that, The siloxane-containing diamine is a siloxane-type diamine, and the siloxane-type diamine has the structural formula shown in formula (II): (II).

3. The modified polyaspartic acid ester resin according to claim 2, characterized in that, The siloxane-type diamine is selected from any one of 4-((tert-butyldimethylsilyl)oxy)phenyl-1,2-diamine, bis(4-aminophenoxy)dimethylsilane, polydimethylsiloxane diamine, bis(3-aminophenoxy)dimethylsilane, and bis(4-aminophenoxy)tetramethylsiloxane; the maleic ester is selected from any one of diethyl maleate and dibutyl maleate.

4. The modified polyaspartic acid ester resin according to any one of claims 1 to 3, characterized in that, The silanediamine and maleate are reacted under inert gas protection with a catalyst at 30-120°C. When the conversion rate of the silanediamine is greater than 99 mol%, the reaction is stopped, and the unreacted maleate is removed to obtain the modified polyaspartic acid ester resin.

5. The modified polyaspartic acid ester resin according to claim 4, characterized in that, The molar ratio of the silanediamine and maleate is 1:(2-8), and the catalyst accounts for 0.3-0.5 wt% of the total mass of the silanediamine and maleate.

6. A method for preparing the modified polyaspartic acid ester resin according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Add the raw materials or the components of the raw materials in sequence to the reaction vessel, and stir and heat under inert gas conditions; S2. Heat to make the amine value ≤40mgKOH / g; S3. Increase the temperature to make the amine value ≤5mgKOH / g; S4. Turn on the thin-film evaporator to remove maleic esters by vacuum heating, and raise the vacuum level to -0.10MPa~-0.05MPa. When the solid content of the product is ≥97±2% and the amine value is ≤3mgKOH / g, cool down and discharge the product.

7. The method for preparing the modified polyaspartic acid ester resin according to claim 6, characterized in that, In step S4, the heating temperature is 100~180℃ and the feed flow rate is 10~30mg / min.

8. The method for preparing the modified polyaspartic acid ester resin according to claim 6, characterized in that, In step S3, the heating temperature is 80~120℃, the reaction time is 30~40 hours, and the viscosity of the obtained product at 25℃ is 2000~10000cps.

9. The method for preparing the modified polyaspartic acid ester resin according to claim 6, characterized in that, In step S2, the heating temperature is 30~50℃, the reaction time is 10~20 hours, and the heating rate is 2~5℃ / min.

10. A polyaspartic acid ester polyurea coating, characterized in that, It was prepared using the modified polyaspartic acid ester resin according to any one of claims 1 to 5.

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