Thixotropic polyaspartic acid ester resin and transparent aspartic polyurea coating
By adding trifunctional isocyanate to aspartic ester resin to form thixotropic polyaspartic ester resin, the balance between anti-sagging properties and transparency of aspartic polyurea coatings is solved, and a transparent coating with excellent anti-sagging properties is prepared.
Patent Information
- Application Number
- CN202511790728.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-01
- Publication Date
- 2026-01-13
AI Technical Summary
Existing aspartic polyurea coatings struggle to balance anti-sagging properties and transparency, especially in transparent varnish coatings used in building waterproofing, where the conventional addition of anti-sagging additives leads to a decrease in transparency.
A small amount of trifunctional isocyanate is added to aspartic ester resin to form thixotropic polyaspartic ester resin through reaction with the first aspartic resin, thus preparing transparent aspartic polyurea coatings and avoiding the use of anti-sagging additives.
A transparent aspartic polyurea coating with good anti-sagging properties was obtained, which improved the anti-sagging properties of the coating and maintained the transparency of the coating without adding anti-sagging additives.
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of aspartic acid ester resins, and relates to a thixotropic polyaspartic acid ester resin and a transparent aspartic polyurea coating. Background Technology
[0002] Polyaspartic acid ester resin, due to its solvent-free and low viscosity characteristics, makes aspartic polyurea coatings widely used in industrial corrosion protection and building waterproofing. Conventional aspartic polyurea coatings have low viscosity and good flowability. In paint products, especially topcoats, anti-sagging agents such as fumed silica, organobentonite, polyamide wax, and hydrogenated castor oil are often added to improve anti-sagging properties. However, this leads to a decrease in the transparency of the coating, such as becoming semi-transparent or even opaque (e.g., milky white). In other applications, such as building waterproofing, a clear varnish coating is required on surfaces like concrete, glass, and wood. In these cases, aspartic polyurea coatings containing anti-sagging agents are insufficient.
[0003] However, there is currently a lack of aspartic polyurea coatings that have good anti-sagging properties and are transparent. Summary of the Invention
[0004] Trifunctional isocyanates, such as HDI trimer, are commonly used curing agents in the field of aspartic polyurea coatings. The applicant unexpectedly discovered that adding a small amount of trifunctional isocyanate to conventional aspartic ester resins can yield thixotropic aspartic ester resins. Based on this, the present invention provides a thixotropic polyaspartic ester resin and a transparent aspartic polyurea coating.
[0005] The technical solution of the present invention is as follows: A thixotropic polyaspartic acid ester resin is obtained by reacting an acetopter resin as shown in formula (1) with a trifunctional isocyanate at a weight ratio of 100:0.1-1. (1) Wherein, X is selected from nonionic m-valent organic groups with a number average molecular weight of 50-5000 containing no more than 2 heteroatoms that are reactive with isocyanate groups at 100℃, and R1 and R2 are individually selected from C1-C8 hydrocarbon groups, m=2-4.
[0007] Preferably, X is selected from a divalent organic group containing cyclohexyl, and R1 and R2 are individually selected from C1-C4 hydrocarbon groups.
[0008] Preferably, the trifunctional isocyanate is selected from one or a combination of two or more of HDI trimer, HDI biuret type trifunctional isocyanate, HDI addition polymerization type trifunctional isocyanate, TDI trimer, MDI trimer, HMDI trimer and IPDI trimer.
[0009] Preferably, the reaction temperature is 10-30℃ and the time is not less than 0.5h.
[0010] Preferably, the thixotropic index of the thixotropic polyaspartic acid ester resin is not less than 2; The test method for the thixotropic index is as follows: at 25°C, the viscosity η1 at a rotational speed of 60 rpm and the viscosity η2 at a rotational speed of 600 rpm are tested using an NDJ-5S rotational viscometer. The thixotropic index is calculated as η1 / η2.
[0011] A transparent aspartic polyurea coating, composed of component A and component B; Component A comprises the thixotropic polyaspartic acid ester resin described in any of the above embodiments; Component B is an isocyanate curing agent.
[0012] Preferably, the thixotropic polyaspartic acid ester resin accounts for no less than 50% of the weight of component A.
[0013] Preferably, component A further comprises a second aspartic resin; The second tertiary aspartic resin is selected from one or a combination of two or more of the following: F420, F520, F330, F220, F421, F2850, F5240A, F221 and F423 from Feiyang Junyan Company.
[0014] Preferably, component A further contains no more than 10% diluent.
[0015] Preferably, the molar ratio of NH groups in component A to NCO groups in component B is 1:1-1.1.
[0016] The beneficial effects of this invention are as follows: By adding a small amount of trifunctional isocyanate to conventional aspartic ester resin and reacting it, a thixotropic polyaspartic ester resin with good thixotropic properties can be obtained. Using this thixotropic polyaspartic ester resin to prepare aspartic polyurea coatings, transparent aspartic polyurea coatings with good anti-sagging properties can be obtained, and good anti-sagging properties can be achieved without adding anti-sagging additives. Detailed Implementation
[0017] The technical solution of the present invention will be further explained and described below through specific embodiments.
[0018] On the one hand, the present invention proposes a thixotropic polyaspartic acid ester resin, which is obtained by reacting the first aspartic resin shown in formula (1) and a trifunctional isocyanate in a weight ratio of 100:0.1-1; (1) Wherein, X is selected from nonionic m-valent organic groups with a number average molecular weight of 50-5000 containing no more than 2 heteroatoms that are reactive with isocyanate groups at 100℃, and R1 and R2 are individually selected from C1-C8 hydrocarbon groups, m=2-4.
[0020] Trifunctional isocyanates are generally used as curing agents for amino resins or aspartic ester resins. This invention uses a small amount of trifunctional isocyanate to react with a primary aspartic resin. The primary aspartic resin undergoes very slight cross-linking and / or forms a branched structure, resulting in a polyaspartic ester resin that exhibits both good flowability and good thixotropy, thus obtaining a thixotropic polyaspartic ester resin. For example, the weight ratio of the primary aspartic resin to the trifunctional isocyanate can be any value or any value between 100:0.1, 100:0.2, 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9, 100:1, etc., without any particular limitation. Within a suitable weight ratio of trifunctional isocyanates, as the amount of trifunctional isocyanate increases, the degree of crosslinking and / or branching of the thixotropic polyaspartic ester resin increases, resulting in higher thixotropy. However, if too much trifunctional isocyanate is used (e.g., a weight ratio of 100:1.5 between the primary isocyanate and the trifunctional isocyanate), the crosslinking of the thixotropic polyaspartic ester resin becomes too high, resulting in poor flowability and even reduced thixotropy. Furthermore, it cannot maintain its transparent state and becomes cloudy.
[0021] In some embodiments, the thixotropic polyaspartic ester resin has a thixotropic index of not less than 2; further, the thixotropic index can be 2-6; the higher the thixotropic index, the better the thixotropy. The test method for thixotropic index is as follows: at 25℃, use an NDJ-5S rotational viscometer to test the viscosity η1 at 60 rpm and the viscosity η2 at 600 rpm. The thixotropic index is calculated as η1 / η2.
[0022] In some embodiments, X is selected from divalent organic groups containing cyclohexyl groups, and R1 and R2 are individually selected from C1-C4 hydrocarbon groups. For example, the above-mentioned first acepart resin can be prepared according to existing methods or can be obtained directly from the market, such as F420, F520, F330, F220, F421, F2850, F5240A, F221, F423, etc. from Feiyang Junyan Company.
[0023] In some embodiments, the trifunctional isocyanate is selected from one or a combination of two or more of HDI trimer, HDI biuret type trifunctional isocyanate, HDI addition polymerization type trifunctional isocyanate, TDI trimer, MDI trimer, HMDI trimer, and IPDI trimer. Among these, HDI trimer is a commonly used trifunctional isocyanate, such as HT-600 and Desmodur N3300 available on the market.
[0024] In some embodiments, the reaction temperature is 10-30°C, and the reaction time is not less than 0.5 h. Due to the high reactivity of the acepartic resin and the trifunctional isocyanate, the reaction can be carried out at room temperature, such as 10°C, 15°C, 20°C, 25°C, or 30°C. If the reaction time is less than 0.5 h, the reaction between the acepartic resin and the trifunctional isocyanate is insufficient, and the thixotropic polyaspartic ester resin obtained is not sufficiently thixotropic. However, if further placed or stored, the acepartic resin and the trifunctional isocyanate can continue to react and achieve a complete reaction, thereby improving the thixotropy. Therefore, in this invention, as long as the acepartic resin and the trifunctional isocyanate react sufficiently at a weight ratio of 100:0.1-1, a thixotropic polyaspartic ester resin with good thixotropic properties can be obtained. The reaction time required for primary allium resins with different reactivity varies. For example, for the highly reactive F420 resin, the reaction time can be 0.5-2 hours when the reaction temperature is 25-30℃; for the less reactive F520 resin, the reaction time can be 5-8 hours when the reaction temperature is 25-30℃.
[0025] On the other hand, the present invention also proposes a transparent aspartic polyurea coating, which is composed of component A and component B; Component A comprises the thixotropic polyaspartic acid ester resin described in any of the above embodiments; Component B is an isocyanate curing agent.
[0026] Because of the good thixotropic properties of thixotropic polyaspartic ester resin, when added to component A and mixed with component B, the resulting aspartic polyurea coating has good transparency and good anti-sagging properties.
[0027] In some embodiments, the thixotropic polyaspartic ester resin accounts for no less than 50% by weight in component A. For example, the weight percentage of the thixotropic polyaspartic ester resin in component A can be any value or any value between 50%, 60%, 70%, 80%, 90%, 100%, etc., without any particular limitation.
[0028] In some embodiments, component A further comprises a second winter resin; In this invention, component A may further include a non-thixotropic second allamic resin, the structure of which may also be as shown in formula (1) above. The second allamic resin can be obtained directly from the market, such as one or a combination of two or more of the following from Feiyang Junyan Company: F420, F520, F330, F220, F421, F2850, F5240A, F221, and F423. Furthermore, the weight percentage of the second allamic resin in component A shall not exceed 30%, for example, the weight percentage may be 0%, 5%, 10%, 15%, 20%, 25%, 30%, etc.
[0029] In some embodiments, component A further contains no more than 10% diluent. The addition of diluent can adjust the viscosity of the aspartic polyurea coating to suit different application requirements, depending on the needs of the application. The diluent can be a polar organic solvent that does not contain active hydrogen, such as PMA, butyl acetate, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, or diethylene glycol dimethyl ether.
[0030] In some embodiments, the molar ratio of NH groups in component A to NCO groups in component B is 1:1-1.1. For example, the molar ratio of NH groups to NCO groups can be any value or any value between 1:1, 1:1.02, 1:1.04, 1:1.05, 1:1.06, 1:1.08, 1:1.1, etc., without any particular limitation.
[0031] There are no particular restrictions on the isocyanate curing agent of component B. It can be an isocyanate trimer such as HDI trimer, or a mixture of isocyanate trimer and diisocyanate monomer, such as a combination of HDI trimer and HDI in a weight ratio of 1:1, or a combination of HDI trimer and HDI in a weight ratio of 2:1, etc.
[0032] The technical solution of the present invention will be further described and illustrated below with reference to various embodiments. Unless otherwise specified, the parts mentioned in the following embodiments are parts by weight.
[0033] Example 1 At 25°C, 0.1g of HT-600 was added to 100g of F420 resin, and the mixture was stirred at 500rpm for 1 hour to obtain a colorless and transparent thixotropic polyaspartic ester resin. The thixotropic index of the thixotropic polyaspartic ester resin obtained in this example was measured to be 2.1 at 25°C.
[0034] The thixotropic polyaspartic ester resin described above was used as component A, and component B was HT-600. The molar ratio of NH groups in component A to NCO groups in component B was 1:1.05. Components A and B were mixed uniformly to obtain a nearly colorless and transparent aspartic polyurea coating with a sag resistance limit of 170 μm and a gel time of 40 min. The cured aspartic polyurea coating was colorless and transparent.
[0035] The sag resistance limit was tested according to the method in GB / T 9264-2012.
[0036] Example 2 The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the amount of HT-600 was adjusted from 0.1g to 0.3g. The remaining steps remained unchanged. This embodiment yielded a colorless and transparent thixotropic polyaspartic ester resin with a thixotropic index of 3.7.
[0037] The thixotropic polyaspartic ester resin described above was used as component A, and component B was HT-600. The molar ratio of NH groups in component A to NCO groups in component B was 1:1.08. Components A and B were mixed uniformly to obtain a nearly colorless and transparent aspartic polyurea coating with a sag resistance limit of 250 μm and a gel time of 38 min. The cured aspartic polyurea coating was colorless and transparent.
[0038] Comparative Example 1 0.3g of polyamide wax paste was added to 100g of F420 resin and dispersed at 50℃ and 1500rpm for 30min, then allowed to stand for 2h to obtain component A. Component A was mixed with HT-600 at a molar ratio of NH groups to NCO groups of 1:1.08 to obtain aspartic polyurea coating, which was milky white in color. The anti-sagging limit was measured to be 150μm and the gel time was 27min. The cured aspartic polyurea coating was milky white and opaque.
[0039] Example 3 The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the amount of HT-600 was adjusted from 0.1g to 0.7g. All other steps remained unchanged. This embodiment yielded a colorless and transparent thixotropic polyaspartic ester resin with a thixotropic index of 5.1; and a nearly colorless and transparent aspartic polyurea coating with a sag resistance limit of 380μm and a gel time of 33min. The cured aspartic polyurea coating was colorless and transparent.
[0040] In this embodiment, after adding 5 wt% of the diluent ethylene glycol dimethyl ether to the aspartic polyurea coating, the anti-sagging limit of the aspartic polyurea coating is 340 μm.
[0041] Example 4 The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the amount of HT-600 was adjusted from 0.1g to 1.0g. All other steps remained unchanged. This embodiment yielded a colorless and transparent thixotropic polyaspartic ester resin with a thixotropic index of 6.0; and a nearly colorless and transparent aspartic polyurea coating with a sag resistance limit of 510μm and a gel time of 30min. The cured aspartic polyurea coating was colorless and transparent.
[0042] In this embodiment, after adding 10 wt% of propylene glycol dimethyl ether as a diluent to the aspartic polyurea coating, the anti-sagging limit of the aspartic polyurea coating is 430 μm.
[0043] Comparative Example 2 The difference between this comparative example and Example 1 is that in Example 1, the amount of HT-600 was adjusted from 0.1g to 1.5g. All other steps remained unchanged. This example yielded a cloudy polyaspartic ester resin with poor flowability.
[0044] Using the polyaspartic acid ester resin obtained in this comparative example as component A, HT-600 as component B, and the molar ratio of NH groups to NCO groups of 1:1.08, 10wt% of propylene glycol dimethyl ether was added to obtain a cloudy aspartic polyurea coating, and the anti-sagging limit was measured to be 110μm.
[0045] Comparing Examples 1-4 and Comparative Example 2, it can be seen that adding too much trifunctional isocyanate will not only affect the transparency of the coating, but also hinder the improvement of anti-sagging performance.
[0046] Example 5 At 25°C, 0.5g of IPDI trimer was added to 50g of F420 resin and 50g of F520 resin, and the mixture was stirred at 500rpm for 5 hours to obtain a colorless and transparent thixotropic polyaspartic ester resin. The thixotropic index of the thixotropic polyaspartic ester resin obtained in this example was measured to be 4.2 at 25°C.
[0047] The thixotropic polyaspartic ester resin obtained in this embodiment was used as component A, and component B was a combination of HT-600 and HDI in a weight ratio of 2:1. The molar ratio of NH groups in component A to NCO groups in component B was 1:1.03. Components A and B were mixed evenly to obtain a nearly colorless and transparent aspartic polyurea coating with a sag resistance limit of 350 μm and a gel time of 47 min. The cured aspartic polyurea coating was colorless and transparent.
[0048] Example 6 At 10°C, 0.2 g of HT-600 was added to 100 g of trifunctional aspartic ester resin (obtained by reacting trifunctional polyether polyol 330N and diethyl maleate in a molar ratio of 1:3), and the mixture was stirred at 500 rpm for 6 h to obtain a colorless and transparent thixotropic polyaspartic ester resin. At 25°C, the thixotropic index of the thixotropic polyaspartic ester resin obtained in this example was measured to be 4.7.
[0049] The thixotropic polyaspartic ester resin obtained in this embodiment was used as component A, and component B was HT-600. The molar ratio of NH groups in component A to NCO groups in component B was 1:1.05. Components A and B were mixed uniformly to obtain a nearly colorless and transparent aspartic polyurea coating with a sag resistance limit of 360 μm and a gel time of 31 min. The cured aspartic polyurea coating was colorless and transparent.
[0050] Example 7 The difference between this embodiment and Embodiment 6 is that in Embodiment 6, the amount of HT-600 was adjusted from 0.2g to 0.1g, while the other steps remained unchanged. At 25°C, the thixotropic index of the thixotropic polyaspartic ester resin obtained in this embodiment was measured to be 3.9; a nearly colorless and transparent aspartic polyurea coating was obtained, with a sag resistance limit of 300μm and a gel time of 32min. The cured aspartic polyurea coating was colorless and transparent.
[0051] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.
Claims
1. A thixotropic polyaspartic acid ester resin, characterized in that, It is obtained by reacting the first acetal resin shown in formula (1) and the trifunctional isocyanate at a weight ratio of 100:0.1-1; （1） Wherein, X is selected from nonionic m-valent organic groups with a number average molecular weight of 50-5000 containing no more than 2 heteroatoms that are reactive with isocyanate groups at 100℃, and R1 and R2 are individually selected from C1-C8 hydrocarbon groups, m=2-4.
2. The thixotropic polyaspartic acid ester resin according to claim 1, characterized in that, X is selected from divalent organic groups containing cyclohexyl groups, and R1 and R2 are individually selected from C1-C4 hydrocarbon groups.
3. The thixotropic polyaspartic acid ester resin according to claim 1, characterized in that, The trifunctional isocyanate is selected from one or a combination of two or more of the following: HDI trimer, HDI biuret type trifunctional isocyanate, HDI addition polymerization type trifunctional isocyanate, TDI trimer, MDI trimer, HMDI trimer, and IPDI trimer.
4. The thixotropic polyaspartic acid ester resin according to claim 1, characterized in that, The reaction is carried out at a temperature of 10-30℃ for a time of not less than 0.5h.
5. The thixotropic polyaspartic acid ester resin according to claim 1, characterized in that, The thixotropic index of the thixotropic polyaspartic acid ester resin is not less than 2. The test method for the thixotropic index is as follows: at 25°C, the viscosity η1 at a rotational speed of 60 rpm and the viscosity η2 at a rotational speed of 600 rpm are tested using an NDJ-5S rotational viscometer. The thixotropic index is calculated as η1 / η2.
6. A transparent aspartic polyurea coating, characterized in that, It consists of component A and component B; Component A comprises the thixotropic polyaspartic acid ester resin according to any one of claims 1-5; Component B is an isocyanate curing agent.
7. The transparent aspartic polyurea coating according to claim 6, characterized in that, The thixotropic polyaspartic acid ester resin accounts for no less than 50% of the weight of component A.
8. The transparent aspartic polyurea coating according to claim 6, characterized in that, Component A also contains second winter resin; The second tertiary aspartic resin is selected from one or a combination of two or more of the following: F420, F520, F330, F220, F421, F2850, F5240A, F221 and F423 from Feiyang Junyan Company.
9. The transparent aspartic polyurea coating according to claim 6, characterized in that, Component A also contains no more than 10% diluent.
10. The transparent aspartic polyurea coating according to claim 6, characterized in that, The molar ratio of NH groups in component A to NCO groups in component B is 1:1-1.1.