Low-viscosity polyaspartic acid ester resin and preparation method thereof

Abstract

The invention provides low-viscosity polyaspartic acid ester resin and a preparation method thereof. Belongs to the paint field. The invention relates to a polyaspartic acid modified nano-silicon dioxide coating which comprises the following components: polyaspartic acid ester, neopentyl glycol diglycidyl ether, nano-silicon dioxide and a silane coupling agent. The preparation method comprises the following steps: cross-linking an amino group in the polyaspartic acid ester with an epoxy group of the neopentyl glycol diglycidyl ether; the primarily modified polyaspartic acid ester is obtained; and mixing the primarily modified polyaspartic acid ester with nano silicon dioxide and a silane coupling agent to obtain the low-viscosity polyaspartic acid ester resin. According to the invention, through the combination of chemical crosslinking and nano-composite technologies, the viscosity, mechanical properties and process efficiency are obviously optimized on the basis of keeping the environmental protection advantage of the polyaspartic acid ester resin, and the development trend of high solid content, low viscosity and high performance in the coating industry is met; the application potential is higher.

Description

Technical Field

[0001] The present invention belongs to the field of coatings, and particularly relates to a low-viscosity polyaspartic ester resin and a preparation method thereof. Background Art

[0002] Polyaspartic ester resin (PAE) is a high-performance aliphatic secondary amino resin and a key component of the third-generation polyurea materials. It is synthesized through Michael addition reaction, and the main raw materials are aliphatic / alicyclic diamines (such as hexamethylenediamine, HMDA, etc.) and maleate or fumarate. Due to the steric hindrance effect of the ester group and alicyclic structure in its molecular structure, and the influence of the electron-withdrawing inductive effect during the reaction with isocyanate, it has a controllable gel time and unique physical and chemical properties.

[0003] Existing PAE resins generally have problems such as a relatively high glass transition temperature of the material, too fast curing speed, and too high viscosity, resulting in poor wetting of materials such as cement and glass, and low adhesion of the coating. Therefore, modifying polyaspartic ester to reduce the viscosity of PAE resin and improve its permeability and wettability is an issue of concern in the industry. Summary of the Invention

[0004] The purpose of the present invention is to propose a modification method for polyaspartic ester resin, mainly aiming at further reducing the viscosity.

[0005] To achieve the above purpose, the present invention provides a low-viscosity polyaspartic ester resin, which includes the following components by mass:

[0006]

[0007] Its preparation method includes the steps:

[0008] S1: Crosslink the amino group in polyaspartic ester with the epoxy group of neopentyl glycol diglycidyl ether to obtain a preliminarily modified polyaspartic ester;

[0009] S2: Mix the preliminarily modified polyaspartic ester with nano-silica and a silane coupling agent to obtain a low-viscosity polyaspartic ester resin.

[0010] Preferably, step S1 of the preparation method is: Mix polyaspartic ester with neopentyl glycol diglycidyl ether and add a basic catalyst, and heat up to at least 90°C; react for at least 4 hours.

[0011] Preferably, the basic catalyst is sodium methoxide, and the addition amount is 0.2 - 0.4 parts by mass.

[0012] Preferably, step S2 of the preparation method is:

[0013] Pretreatment: Disperse nano-silica in a solvent, add a catalyst, and perform ultrasonic treatment for dispersion; then add a silane coupling agent; stir at at least 70 °C for at least 5 h;

[0014] Pre-reaction: Ultrasonically treat a part of nano-silica and preliminarily modified polyaspartate at at least 60 °C for at least 1 h;

[0015] Post-dispersion: Add the remaining nano-silica to the system; stir evenly for dispersion, with a stirring rate of at least 3000 rpm and a time of at least 30 min.

[0016] Preferably, the catalyst is an organometallic complex, and the addition amount is 0.2 - 0.4 parts by mass.

[0017] Preferably, in the pretreatment step, oleic acid is also added; the addition amount of the oleic acid is 0.4 - 0.8 parts.

[0018] Preferably, the nano-silica is hydrophobic nano-silica; its particle size D95 ≤ 20 nm.

[0019] In the present invention:

[0020] By introducing epoxy crosslinking to reduce the viscosity, crosslinking occurs between the amino groups of neopentyl glycol diglycidyl ether and polyaspartate to form a preliminarily modified resin. This crosslinking reaction can proceed efficiently under the action of a basic catalyst, which can not only reduce the entanglement of resin molecular chains but also adjust the viscosity of the system through the flexible chain segments of the epoxy groups.

[0021] The present invention adopts a stepwise dispersion process (pretreatment - pre-reaction - post-dispersion), and combines a silane coupling agent and oleic acid to perform surface treatment on hydrophobic nano-silica (D95 ≤ 20 nm). This method effectively inhibits the agglomeration of nano-particles, enhances their dispersion in the resin, and thus reduces the overall viscosity of the system. At the same time, the uniform distribution of nano-particles helps to improve the hardness and wear resistance of the coating.

[0022] The addition of nano-silica significantly improves the mechanical strength of the coating. The hydrophobic modified nano-particles can enhance the adhesion between the resin and the substrate, and at the same time form chemical bonding through the silane coupling agent, improving the weather resistance and chemical corrosion resistance. In addition, the epoxy crosslinked structure can endow the coating with better impact resistance.

[0023] In the pretreatment stage of the present invention, ultrasonic dispersion and oleic acid assistance (S2 step) are used to optimize the interfacial compatibility of nano-materials, avoiding the increase in energy consumption caused by high-speed stirring in the later stage. In the pre-reaction stage, part of the nano-silica is pre-mixed with the modified resin to ensure the core interface combination, and the remaining particles are supplemented in the post-dispersion stage to improve the efficiency.

[0024] By combining chemical crosslinking and nanocomposite technology, the present invention significantly optimizes viscosity, mechanical properties and process efficiency while maintaining the environmental protection advantages of polyaspartate resin, meeting the development trend of high solid content, low viscosity and high performance in the coating industry; it has high application potential. Detailed implementation manners

[0025] To better understand the present invention, the present invention will be further described below in conjunction with specific serial numbers. The terms used in the serial numbers are for describing specific embodiments and do not constitute a limitation on the protection scope of the present invention.

[0026] In the detailed implementation manners, the experimental methods used are all conventional methods unless otherwise specified, and the materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified.

[0027] The sources of some raw materials used in the present invention are as follows:

[0028] Nano-silica: TSP-H10

[0029] Polyaspartate: JH-8142 two-component polyurethane / polyurea

[0030] Organometallic complex: dibutyltin dilaurate

[0031] Silane coupling agent: KH550

[0032] Example 1 Preparation of low-viscosity polyaspartate resin, including the following steps:

[0033] S1 Weighing: The following components are included by mass parts:

[0034]

[0035] S2: Mix polyaspartate with neopentyl glycol diglycidyl ether and add sodium methoxide, and heat up to 90 °C; react for 4 h; obtain preliminarily modified polyaspartate.

[0036] S3: Disperse nano-silica in 3,3',5,5'-azobenzenetetracarboxylic acid and add dibutyltin dilaurate and oleic acid, and ultrasonically disperse for 30 min; then add KH550; heat up to 70 °C and stir for 5 h.

[0037] S4: Ultrasonically treat 20WT% nano-silica and preliminarily modified polyaspartate at 60 °C for 1 h.

[0038] S5: Add the remaining nano-silica to the system; stir evenly and disperse, the stirring rate is at least 3000 rpm and the time is at least 30 min.

[0039] Example 2 Preparation of low-viscosity polyaspartate resin, comprising the following steps:

[0040] S1 Weighing: The following components are included by mass parts:

[0041]

[0042] S2: Mix polyaspartate with neopentyl glycol diglycidyl ether, add sodium methoxide, and heat up to 90 °C; react for 4 h; obtain preliminarily modified polyaspartate;

[0043] S3: Disperse nano-silica in 3,3',5,5'-azobenzenetetracarboxylic acid, add dibutyltin dilaurate and oleic acid, and ultrasonically disperse for 30 min; then add KH550; heat up to 70 °C and stir for 5 h;

[0044] S4: Ultrasonically treat 20 WT% nano-silica and preliminarily modified polyaspartate at 60 °C for 1 h;

[0045] S5: Add the remaining nano-silica into the system; stir evenly and disperse, with the stirring rate being at least 3000 rpm and the time being at least 30 min.

[0046] Example 3 Preparation of low-viscosity polyaspartate resin, comprising the following steps:

[0047] S1 Weighing: The following components are included by mass parts:

[0048]

[0049] S2: Mix polyaspartate with neopentyl glycol diglycidyl ether, add sodium methoxide, and heat up to 90 °C; react for 4 h; obtain preliminarily modified polyaspartate;

[0050] S3: Disperse nano-silica in 3,3',5,5'-azobenzenetetracarboxylic acid, add dibutyltin dilaurate and oleic acid, and ultrasonically disperse for 30 min; then add KH550; heat up to 70 °C and stir for 5 h;

[0051] S4: Ultrasonically treat 20 WT% nano-silica and preliminarily modified polyaspartate at 60 °C for 1 h;

[0052] S5: Add the remaining nano-silica into the system; stir evenly and disperse, with the stirring rate being at least 3000 rpm and the time being at least 30 min.

[0053] Example 4 Preparation of modified polyaspartate resin, comprising the following steps:

[0054] S1 Weighing: It includes the following components calculated by mass parts:

[0055]

[0056] S2: Mix polyaspartate and neopentyl glycol diglycidyl ether, add sodium methoxide, and heat up to 90 °C; react for 4 h; obtain modified polyaspartate.

[0057] Preparation of the modified polyaspartate resin in Example 5 includes the following steps:

[0058] S1 Weighing: It includes the following components calculated by mass parts:

[0059]

[0060] S2: Disperse nano-silica in 3,3',5,5'-azobenzenetetracarboxylic acid, add dibutyltin dilaurate and oleic acid, and ultrasonically treat for 30 min for dispersion; then add KH550; heat up to 70 °C and stir for 5 h;

[0061] S3: Ultrasonically treat 20WT% nano-silica and polyaspartate at 60 °C for 1 h;

[0062] S4: Add the remaining nano-silica to the system; stir evenly for dispersion, with the stirring rate at least 3000 rpm and the time at least 30 min.

[0063] Mix the sample of the example and HDI trimer (BASF HI100) in a mass ratio of 5:1 to obtain a polyaspartate polyurea coating. Conduct a viscosity test on the coating performance of the coating on the cement matrix, and the results are shown in Table 1.

[0064] The coating performance is tested by surface roller coating, with the test temperature of 25 °C and the humidity of 80%; the test method for the tensile bond strength of the coating refers to the standard of "GB / T 22374-2018 Floor Coating Materials".

[0065] The experimental results are shown in Table 1 below.

[0066] Table 1

[0067] Serial number Viscosity (20℃ / cps) Coating tensile bond strength (MPa) Example 1 438 5.0 Example 2 503 5.1 Example 3 556 5.1 Example 4 316 3.3 Example 5 1020 5.4 JH-8142 872 3.5

[0068] As can be seen from Table 1, although the nano-silica of the present invention will increase the viscosity, it greatly improves the firmness of the coating; in order to solve the increase in viscosity, the present invention uses neopentyl glycol diglycidyl ether modification to solve this problem; it can be known that when a sufficient amount of neopentyl glycol diglycidyl ether is added, its viscosity significantly decreases; and when a certain amount of nano-silica is added at the same time, the bond strength can be greatly improved while ensuring a relatively low viscosity.

[0069] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification without departing from the present invention shall be included within the scope of the technical solution of the present invention.

Claims

1. A low-viscosity polyaspartate ester resin, characterized in that, Comprises the following components by mass parts: Its preparation method comprises the steps: S1: The amino group in the polyaspartate ester cross-links with the epoxy group of neopentyl glycol diglycidyl ether; obtaining a preliminarily modified polyaspartate ester; S2: The preliminarily modified polyaspartate ester is mixed with nano-silica and a silane coupling agent to obtain a low-viscosity polyaspartate ester resin.

2. The low-viscosity polyaspartate ester resin according to claim 1, characterized in that, The preparation method step S1 is: Mix the polyaspartate ester with neopentyl glycol diglycidyl ether and add a basic catalyst, and heat up to at least 90 °C; react for at least 4 h.

3. The low-viscosity polyaspartate resin according to claim 2, characterized in that, The basic catalyst is sodium methoxide, and the addition amount is 0.2 - 0.4 mass parts.

4. The low-viscosity polyaspartate resin according to claim 1, characterized in that, The preparation method step S2 is: Pretreatment: Disperse the nano-silica in a solvent and add a catalyst, and perform ultrasonic treatment for dispersion; then add a silane coupling agent; stir at at least 70 °C for at least 5 h; Pre-reaction: Ultrasonically treat a part of the nano-silica and the preliminarily modified polyaspartate ester at at least 60 °C for at least 1 h; Post-dispersion: Add the remaining nano-silica into the system; stir evenly for dispersion, the stirring rate is at least 3000 rpm, and the time is at least 30 min.

5. The low-viscosity polyaspartate resin according to claim 4, characterized in that, The catalyst is an organometallic complex, and the addition amount is 0.2 - 0.4 mass parts.

6. The low-viscosity polyaspartate ester resin according to claim 4, characterized in that, In the pretreatment step, oleic acid is also added; the addition amount of the oleic acid is 0.4 - 0.8 parts.

7. The low-viscosity polyaspartate ester resin according to claim 1, characterized in that, The nano-silica is hydrophobic nano-silica; its particle size D95 ≤ 20 nm.

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