ASPARTIC POLYUREA COATING

Abstract

The present application relates to a field of anti-corrosion coating, in particular, relates to an aspartic polyurea coating including a polyaspartic acid ester: 36%-60%; a ketoimine: 4%-8%; a dispersant: 0.5%-1.0%; an organotin catalyst: 0.1%-0.2%; a titanium white powder: 0%-48%; a thixotropic agent: 0.2%-1.0%; a leveling agent: 0.05%-0.3%; an antifoamer: 0.1%-1.0%; an antiager: 0%-3.0%; a coupling agent: 0%-5%; a diluent: 0%-10% and component B isocyanate curing agent.

Claims

1. An aspartic polyurea coating, comprising a mixture and an isocyanate curing agent, wherein the mixture comprises the following components by weight: a polyaspartic acid ester: 36%-60%; a ketoimine: 4%-8%; a dispersant: 0.5%-1.0%; an organotin catalyst: 0.1%-0.2%; a titanium white powder: 0%-48%; a thixotropic agent: 0.2%-1.0%; a leveling agent: 0.05%-0.3%; an antifoamer: 0.1%-1.0%; an antiager: 0%-3.0%; a coupling agent: 0%-5%; and a diluent: 0%-10%, based on a total weight of the mixture; and the mixture further comprises a water absorbent being present in a proportion of 1%-3% by weight based on a total weight of the aspartic polyurea coating.

2. The aspartic polyurea coating according to claim 1, wherein, the polyaspartic acid ester comprises F520 and F2850; F520 is present in a proportion of 32%-60% by weight based on the total weight of the aspartic polyurea coating; F2850 is present in a proportion of no greater than 4% by weight based on the total weight of the aspartic polyurea coating.

3. The aspartic polyurea coating according to claim 1, wherein, the ketoimine is prepared by condensation of a ketone and a polyamine, and the polyamine is at least one selected from a group consisting of 4,4′-diaminodicyclohexylmethane, 3,3′dimethyl-4,4′-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane, isophorondiamine, 4-methylcyclohexane-1,3-diamine and polyetheramine D230.

4. The aspartic polyurea coating according to claim 1, wherein, the dispersant is at least one selected from a group consisting of an anionic dispersant, a cationic dispersant, a non-ionic dispersant, a zwitterionic wetting dispersant, an electrically neutral wetting dispersant, a polymer hyperdispersant and a free radical hyperdispersant.

5. The aspartic polyurea coating according to claim 1, wherein, the thixotropic agent is at least one selected from a group consisting of fumed silica, organic bentonite, castor oil and polyamide.

6. The aspartic polyurea coating according to claim 1, wherein, the antiager comprises an ultraviolet (UV) absorbent and a light stabilizer; and wherein the UV absorbent is present in a proportion of 0%-3% by weight based on the total weight of the aspartic polyurea coating, and the light stabilizer is present in a proportion of 0%-3% by weight based on the total weight of the aspartic polyurea coating.

7. The aspartic polyurea coating according to claim 1, wherein, the diluent comprises 50% of butyl acetate and 50% of 2-acetoxy-1-methoxypropane based on a total weight of the diluent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 shows an effect of aging time on a color difference in aging resistance of a coating at 90% solid content in Examples 1-3 and Comparative examples 1-5.

[0039] FIG. 2 shows an effect of aging time on a glossiness in aging resistance of the coating at 90% solid content in Examples 1-3 and Comparative examples 1-5.

[0040] FIG. 3 shows the effect of aging time on the color difference in aging resistance of the coating at 90% solid content in Examples 4-7.

[0041] FIG. 4 shows the effect of aging time on the color difference in aging resistance of the coating at 90% solid content in Example 4 and Comparative Examples 1-5.

[0042] FIG. 5 shows the effect of aging time on the glossiness difference in aging resistance of the coating at 90% solid content in Examples 4-7.

[0043] FIG. 6 shows the effect of aging time on the glossiness difference in aging resistance of the coating at 90% solid content in Example 4 and Comparative Examples 1-5.

DETAILED DESCRIPTION

[0044] With a spread of environmental protection concepts and policies such as “clear waters and green mountains are as valuable as mountains of gold and silver”, in the coating industry, environmental-friendly coatings are increasingly favored by people, especially an aspartic polyurea coating with high solid content, and the VOCs content thereof is less than 15%, even 0. However, there is a problem that an activation period and drying speed cannot be satisfied simultaneously during a use process of the aspartic polyurea coating.

[0045] The inventor found that an factor affecting the activation period and drying speed of the coating is introduction of water during using the coating. Therefore, the inventor tried to add ketoimine into aspartic polyurea coating, in order to extend the activation period of the coating by a hydrolysis of ketoimine, and improve the drying speed of the coating at the same time. After numerous experiments, the activation period was nearly doubled, and the drying time was reduced from 8.2 h to 6.5 h. However, a best drying time of coating stipulated in the coating industry is 2-5 h, and a coating construction and recoalability are good within this time range. Thus, it is necessary to further optimize the experiment to improve the drying speed of the coating. After numerous experiments, the inventor found that adding organotin catalyst can improve the drying speed of the coating, especially when the proportion of polyaspartic acid ester, ketoimine and organotin catalyst was strictly controlled, the drying speed of the coating can be less than 5 h, which meets a standard of high quality coating.

[0046] The present application is further described in detailed in combination with tables and Examples.

Components and Their Corresponding Models

[0047] Dispersant: BYK163 (commercially available from BYK-Chemie GmbH); [0048] Titanium white powder: R606 (commercially available from NINGBO XINFU TITANIUM DIOXIDE CO., LTD); [0049] Thixotropic agent: fumed silica; [0050] Water absorbent: 3A molecular sieve; [0051] Leveling agent: EFKA3600 (commercially available from BASF); [0052] Antifoamer: BYK085 (commercially available from BYK-Chemie GmbH); [0053] UV absorbent: 1130 (commercially available from BASF); [0054] Light stabilizer: 292 (commercially available from BASF); [0055] Coupling agent: KH-560 (commercially available from Dow Chemical Company); [0056] Ketimine: IPDA ketoimine (commercially available from Shenzhen Feiyang Protech Corp., Ltd).

EXAMPLES

[0057] Component B isocyanate curing agent adopts HDI trimer, in which the isocyanate curing agent added was controlled at an amount such that an amount of isocyanate groups in the isocyanate curing agent can completely react with the secondary amine group of polyaspartic acid ester and a primary amine group after ketoimine hydrolysis in the coating. In an actual application, an excessive addition of isocyanate can ensure a complete reaction of the secondary amine group of polyaspartic acid ester and the primary amine group after ketoimine hydrolysis. The amount of isocyanate groups can be controlled as 1.05-1.5 times of a total amount of the secondary amine group of polyaspartic acid ester and the primary amine group after ketoimine hydrolysis.

TABLE-US-00001 weight percentage of each component of the mixture with component A polyaspartic acid ester as main body in Examples 1-3 and Comparative Examples 1-5 Example 1 Example 2 Example 3 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Polyaspartic acid ester F520 36% 48% 60% 36% 36% 36% 36% 78% Polyaspartic acid ester F2850 0 0 0 0% 0% 0% 0% 0 Ketoimine 6% 4% 4% 0 10% 4% 4% 8% Organotin catalyst 0.15% 0.20% 0.20% 0.10% 0.20% 0 0.30% 0 Dispersant 1% 1% 1% 1% 1% 1% 1% 1% Titanium white powder 43% 33% 23% 48% 39% 45% 45% 0 Thixotropic agent 0.30% 0.30% 0.30% 0.30% 0.30% 0.30% 0.20% 0 3A molecular sieve 3% 3% 1% 3% 3% 3% 3% 0 Leveling agent 0.10% 0.10% 0.10% 0.30% 0.10% 0.30% 0.10% 0.20% Antifoamer 0.25% 0.20% 0.20% 1% 0.20% 0.20% 0.20% 0.40% UV absorbent 2% 2% 2% 2% 2% 2% 2% 2% Light stabilizer 1% 1% 1% 1% 1% 1% 1% 1% Coupling agent 1% 1% 1% 1% 1% 1% 1% 1% 2-Acetoxy-1-met hoxypropane 3.10% 3.10% 3.10% 3.10% 3.10% 3.10% 3.10% 4.20% Butyl acetate 3.10% 3.10% 3.10% 3.10% 3.10% 3.10% 3.10% 4.20% Total 100% 100% 100% 100% 100% 100% 100% 100%

[0058] In Examples 1-2, the aspartic polyurea coatings were prepared by the following method:

[0059] polyaspartic acid ester F520, dispersant, organotin catalyst, titanium white powder, thixotropic agent, water absorbent, leveling agent, antifoamer, UV absorbent, light stabilizer were weighed and undergone a manual low speed mixing. Then, a dispersion was conducted in a high speed disperser with a rotational speed of 1500 rpm for 8 min, and a mixed material were obtained. Then, the mixed material was poured into a reactor with heating and vacuumizing functions. The reactor was heated to 120° C. and vacuumized to remove water at the same time for 60 min. Then, the coupling agent, 2-acetoxy-1-methoxypropane, butyl acetate and ketoimine were added under stirring at a low speed, and mixed evenly to obtain a mixture with component A polyaspartic acid ester as the main body.

[0060] Before using the coating, the mixture were stirred evenly, into which the component B was added and stirred evenly to obtain a stable and uniform aspartic polyurea coating.

[0061] In Examples 3 and Comparative examples 1-5, the aspartic polyurea coatings were prepared by the following method:

[0062] polyaspartic acid ester F520, dispersant, organotin catalyst, titanium white powder, thixotropic agent, water absorbent, leveling agent, antifoamer, UV absorbent, light stabilizer were weighed and undergone a manual low speed mixing. Then, a dispersion was conducted in a high speed disperser with a rotational speed of 1500 rpm for 8 min, and a mixed material were obtained. Then, the mixed material was poured into a reactor with heating and vacuumizing functions. The reactor was heated to 120° C. and vacuumized to remove a water at the same time for 60 min. Then, the coupling agent, 2-acetoxy-1-methoxypropane and butyl acetate were added under stirring at a low speed, and mixed evenly to obtain a mixture with component A polyaspartic acid ester as the main body.

[0063] Before using the coating, the mixture were stirred evenly, into which the component B and the ketoimine were successively added and stirred evenly to obtain a stable and uniform aspartic polyurea coating.

Performance Analysis

[0064] TABLE-US-00002 drying time of the coating at 90% solid content in Examples 1-3 and Comparative examples 1-5 Examples Example 1 Example 2 Example 3 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Dry to touch/h 4 4.1 4.3 8 1.8 6.5 6.1 5

[0065] It is stipulated in the coating industry when the drying time of the coating is 2-5 h, the drying speed is appropriate, and the prepared coating is a high quality coating.

[0066] In table 2, in Examples 1-3, the polyaspartic acid ester F520 was used, the ketoimine and the organotin catalyst were both added. In Comparative example 1, the ketoimine was not added, but the organotin catalyst was added. In Comparative example 2, an excessive amount of ketoimine and a proper amount of organotin catalyst were added. The dry to touch time of Examples 1-3 were less than 5 h, which meets the standard of high quality coating. However, the dry to touch time of Comparative example 1 was 8 h, and the dry to touch time of Comparative example 2 was 1.8 h, both of which fail to meet the standard of high quality coating.

[0067] In Examples 1-3, the organotin catalyst was added. In Comparative example 3, the organotin catalyst was not added. In Comparative example 4, the organotin catalyst was added excessively. The dry to touch time of Examples 1-3 were not greater than 4.3 h, and the drying time is short, so the coating of Examples 1-3 were high quality coating. However, the dry to touch time of Comparative examples 3-4 were greater than 5 h, and coating properties were poor.

[0068] Comparing Example 1, Comparative example 3 and Comparative example 5, in Comparative example 3, the ketoimine was added, but the organotin catalyst was not added. For Comparative example 5 as varnish, only the ketoimine was added, but the organotin catalyst was not added. After a test, it can be seen that the dry to touch time was 6.5 h, and there was no change due to a difference of main components of the coating.

TABLE-US-00003 the activation period of the coating at 90% solid content in Examples 1-3 and Comparative examples 1-5 Examples Example 1 Example 2 Example 3 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Activation period/min 150 155 157 55 155 136 163 139

[0069] As can be seen from table 1 and table 3, no ketoimine was added in Comparative example 1, but the ketoimine was added in other Examples and Comparative examples. The activation period of Comparative example 1 was only 55 min, and the activation periods of other Examples and Comparative examples were greater than 60 min.

[0070] It is stipulated in the coating industry when a color difference is less than 3.0, an aging resistance of the coating is level 1 that is better.

[0071] In combination with Examples 1-3, Comparative examples 1-5 and FIG. 1, in Examples 1-3, the ketoimine was added, and the color difference was less than 3.0 within 744 h. No ketoimine was added in Comparative example 1, and excessive amount of ketoimine was added in Comparative example 2, which affected the color difference, and the color difference exceeded 3.0 when the aging time was 456 h.

[0072] In combination with Examples 1-3, Comparative examples 3-4 and FIG. 1, the catalyst and the ketoimine were added in Examples 1-3, no organotin catalyst was added in Comparative example 3, and excessive amount of organotin catalyst was added in Comparative example 4. It can be seen from FIG. 1 that, there was substantially no difference between a color difference change of Comparative example 3 and that of Examples 1-3, and the color difference of Comparative example 4 exceeded 3.0 at 744 h.

[0073] In combination with Examples 1-3 and Comparative example 5, the coating in Comparative example 5 was varnish, and the coatings in Examples 1-3 were common coating. It can be seen from FIG. 1 that, under a condition of the same aging time, the color difference of Comparative example 5 was not higher than those of Examples 1-3.

[0074] It can be seen from FIG. 2 that, with an extension of aging time, a glossiness decreases rapidly in Examples 1-3, and the glossiness was lower than 40 at 1008 h. In Comparative example 1-2, the amount of the ketoimine added was changed, but there was substantially no difference in terms of a change of glossiness. In Comparative example 3, no organotin catalyst was added, the glossiness thereof had little change with the extension of aging time. In Comparative example 4, excessive amount of organotin catalyst was added, the glossiness thereof changed fast with the extension of aging time, and was close to 40 at 456 h. The coating in Comparative example 5 was varnish, and the glossiness thereof was better and still exceeded 80 even at 2880 h.

TABLE-US-00004 weight percentage of each component of the mixture with component A polyaspartic acid ester as main body in Examples 4-7 Example 4 Example 5 Example 6 Example 7 Polyaspartic acid ester F520 32% 46% 52% 32% Polyaspartic acid ester F2850 4% 2% 8% 4% IPDA ketoimine 4% 8% 4% 4% Organotin catalyst 0.20% 0.10% 0.10% 0.20% Dispersant 1% 1% 1% 1% Titanium white powder 45% 29% 26% 48% Thixotropic agent 0.30% 0.30% 0.30% 0.30% 3A molecular sieve 3% 3% 2% 3% Leveling agent 0.10% 0.20% 0.20% 0.10% Antifoamer 0.20% 0.20% 0.20% 0.20% UV absorbent 2% 2% 2% 0 Light stabilizer 1% 1% 1% 0 Coupling agent 1% 1% 1% 1% 2-Acetoxy-1-methoxypropane 3.10% 3.10% 1.10% 3.10% Butyl acetate 3.10% 3.10% 1.10% 3.10% Total 100% 100% 100% 100%

[0075] The preparation methods of aspartic polyurea coating in Examples 4-7 were same as that in Examples 1-2.

Performance Analysis

[0076] TABLE-US-00005 drying time of coating at 90% solid content in Examples 4-6 Examples Example 4 Example 5 Example 6 Example 7 Dry to touch/h 3.3 3.8 5.8 3.5

[0077] In Examples 4-7, the polyaspartic acid ester F520 and F2850 were used. It can be seen from table 5 that, when the polyaspartic acid ester F520 and F2850 were used together, the drying time of the prepared aspartic polyurea coating was shorter. In particular, when a weight ratio of the polyaspartic acid ester F520 to F2850 was 8:1 (corresponding to Examples 4), it was shown in FIG. 1 that the drying time was shorter, and the drying speed was faster.

TABLE-US-00006 activation period of coating at 90% solid content in Examples 4-6 Examples Example 4 Example 5 Example 6 Example 7 Activation period/min 160 145 65 134

[0078] In Example 4, the weight ratio of polyaspartic acid ester F520 to F2850 was 8:1, and the activation period was up to 160 min. In Example 5, the weight ratio of polyaspartic acid ester F520 to F2850 was 23:1, and the activation period was 145 min. In Example 6, the amount of polyaspartic acid ester F2850 added was 8% by weight, but the activation period of the prepared coating was only 65 min. In Example 7, no UV absorbent and no light stabilizer were added, the activation period was 134 min. The activation period of Example 4 was the longest in the Examples of the present application.

[0079] In Examples 4-7, the polyaspartic acid ester was F520 and F2850. The color difference was not less than 2.5 at 774 h. In Example 7, no UV absorbent and no light stabilizer was added, the color difference was greater than 3.0 when the aging time was 722 h.

[0080] In combination with FIG. 4, Example 4 and Comparative examples 1-2, in Example 4, the ketoimine and the organotin catalyst were added; in Comparative example 1, no ketoimine was added; in Comparative example 2, excessive amount of ketoimine was added. It can be seen from FIG. 4 that, the color difference of Example 4 was greater than 2.5 when the aging time was 744 h, but the color differences of Comparative example 1 and Comparative example 2 were greater than 3.

[0081] In combination with Example 4 and Comparative examples 3-4, in Example 4, the ketoimine and the organotin catalyst were added; in Comparative examples 3-4, the ketoimine was added; however, in Comparative example 3, no organotin catalyst was added; in Comparative example 4, excessive amount of organotin catalyst was added. When the aging time was 744 h, the color difference of Example 4 was greater than 2.5, but the color difference of Comparative example 3 was less than 2.5, the aging resistance is level 1, and the color difference of Comparative example 4 was close to 3.5.

[0082] In combination with Example 4 and Comparative example 5, it can be seen from FIG. 4 that, the coating in Comparative example 5 was varnish, and the color difference thereof was still less than 3 when the aging time was 2448 h.

[0083] It can be seen that, the aging resistance of Example 4 was average, and it is more suitable to be used as a DTM single coating that does not require a durable weather resistance situation, but requires corrosion and weather resistance at the same time but the requirements are not high, or as a primer or an intermediate coating.

[0084] It can be seen from FIG. 5 that, with the extension of aging time, the glossiness of Examples 4-7 decreases fastest, in which Example 7 was the most obvious. At 456 h, the glossiness of Example 4 was still close to 80, but at 744 h, the glossiness was less than 20. That is, a glossiness change rate was very fast.

[0085] It can be seen from FIG. 6 that, when the aging time was less than 360 h, the glossiness of Example 4 and Comparative examples 1-5 were all greater than 80. With the extension of aging time, the glossiness of Example 4, Comparative examples 1-2 and 4 decreases rapidly. In particular, the glossiness of Example 4 was less than 20 at 744 h. Thus, the coating prepared in the present application was easy to lose gloss in a long time, and was more suitable for being used as a primer or an intermediate coating.

[0086] In summary, when the ketoimine and organotin catalyst were added to the aspartic polyurea system at the same time, the drying speed of the coating was fast, the time period was shortened to 3.3 h, and the activation period was long. However, when the polyaspartic acid ester of the coating was a composite component, that is, including F520 and F2850 at the same time, the glossiness and the color difference of the coating were easy to change, which was more suitable for being used as a primer or an intermediate coating.

[0087] The above are the preferred embodiments of the present application, which are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.