Preparation method of double-crosslinking type self-polishing antifouling paint base resin

Abstract

The invention provides a preparation method of double-crosslinking type self-polishing antifouling paint base resin. The double-crosslinking type self-polishing antifouling paint base resin comprises fluorine-containing hydroxyl acrylic resin and polyester resin in a mass ratio of (1: 1)-(1: 9). The degradable polyester resin is used as a self-polishing component, the acrylate resin component and the polyester resin form a double-crosslinking network structure to enhance the mechanical strength of the coating, and the double-crosslinking structure can effectively improve the mechanical strength of the resin and enhance the flexibility and impact resistance of the coating; a new thought is provided for preparing a novel collision-resistant high-flexibility antifouling coating.

Description

Technical Field

[0001] The invention relates to the technical field of marine antifouling, and in particular to a method for preparing a double-crosslinked self-polishing antifouling paint base resin. Background Art

[0002] Marine fouling, the attachment and growth of marine organisms on surfaces exposed to seawater, is a critical and unavoidable challenge in the development of marine resources and the marine industry. Not only does it roughen the surface of ships, significantly increasing navigation resistance and fuel consumption, but it can also cause severe erosion, blockage, and reduced efficiency in facilities such as desalination systems, power plant cooling units, and submarine pipelines, resulting in significant economic losses. Therefore, marine anti-fouling is of great significance for ensuring the sustainable use of marine resources and promoting the healthy development of the marine industry.

[0003] Applying antifouling coatings is widely recognized as the most economical and effective antifouling method. Self-polishing antifouling coatings are a common antifouling coating used on ships and other underwater structures. Currently, the most commonly used base resin for self-polishing antifouling coatings is a linear acrylic polymer. For example, Chinese patent application number CN202410835682.1 discloses a hydrolyzable linear self-polishing antifouling coating and its preparation method. This invention combines an ion exchange resin, a silane ester resin, and an additive A in a specific ratio to create a linear self-polishing resin system. This system, when applied to antifouling paint, not only produces a linear self-polishing antifouling paint but also prevents the unstable hydrolysis of the ion exchange resin and silane ester resin during storage in tanks. This solution can significantly extend the antifouling life of the coating, reduce surface roughness, and minimize fuel consumption. However, if the hull or underwater structure surface is impacted or undergoes significant deformation, the coating is susceptible to brittle cracking and shedding, leading to failure.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The problem solved by the present invention is that the existing self-polishing antifouling coating has poor mechanical properties and is prone to brittle cracking and falling off after collision or large-scale deformation.

[0006] To solve the above problems, the present invention provides a method for preparing a double-crosslinked self-polishing antifouling paint base resin, comprising component B, wherein component B comprises a fluorinated hydroxyl acrylic resin and a polyester resin in a mass ratio of 1:1 to 1:9, wherein the structural formula of the fluorinated hydroxyl acrylic resin is:

[0007] The structural formula of the polyester resin is:

[0008] Preferably, the double-crosslinked self-polishing antifouling paint base resin further comprises component A, wherein component A is an isocyanate-containing curing agent, wherein the molar ratio of the hydroxyl group of component B to the isocyanate group of component A is 0.8-1.2:1.

[0009] Preferably, the fluorine-containing hydroxyl acrylic resin is prepared by the following method: S1, HEMA, MMA, BA, FMA, and AIBN are weighed according to amount, and then a certain amount of solvent is added to fully dissolve them to form a mixed solution; S2, a certain amount of solvent is added to a reaction container and heated to 85-95°C, and the mixed solution of step S1 is added dropwise to the reaction container at a uniform speed within 2.5-3.5 hours under stirring, and then a small amount of AIBN-containing solution is added dropwise, and the reaction is continued for 2-4 hours to obtain the obtained product.

[0010] As an example of the present invention, the fluorinated hydroxyl acrylic resin is prepared by the following method: S1. HEMA, MMA, BA, FMA, and AIBN are weighed according to the amount, and then 50% of the prescribed amount of solvent is added to fully dissolve them to form a mixed solution; S2. 45% of the prescribed amount of solvent is added to a reaction vessel and heated to 85-95°C. While stirring, the mixed solution of step S1 is uniformly added dropwise to the reaction vessel over 2.5-3.5 hours. Then, a small amount of a solution formed by dissolving AIBN in 5% solvent is added dropwise, and the reaction is continued for 2-4 hours to obtain the obtained product. Preferably, the solvent is xylene.

[0011] Preferably, in step S1, the mass ratio of hexafluorobutyl methacrylate FMA to the total monomer mass ratio is 5% to 20%, the mass ratio of azobisisobutyronitrile AIBN to the total monomer mass ratio is 0.5% to 2%, the mass ratio of methyl methacrylate to butyl methacrylate is 65:35 to 55:45, and the content of hydroxyethyl methacrylate accounts for 5% to 15% of the total monomer mass. The dropwise addition rate of the mixed solution in step S2 is 50 to 90 g / h, and the stirring speed is 400 to 800 rpm.

[0012] Preferably, the polyester resin is prepared according to the following method: adding an appropriate amount of solvent to a reaction vessel, then adding lactide and caprolactone in a molar ratio of 0.8-1.2:1, heating to 120-135°C until the lactide is completely dissolved, then adding 0.08-0.1wt% of a catalyst, maintaining the temperature at 120-135°C and stirring for 5-7h to obtain the polyester resin.

[0013] Preferably, the catalyst is dibutyltin dilaurate.

[0014] Preferably, component B comprises 310-340 parts of a double-crosslinked self-polishing antifouling paint base resin, 4-6 parts of a defoamer, 240-270 parts of talc, 110-150 parts of ZnO, and 30-40 parts of an anti-settling agent. Preferably, component B also comprises 30-40 parts of a black color paste and 5-10 parts of a blue color paste. As an example of the present invention, component B comprises 324.2-326.8 parts of a double-crosslinked self-polishing antifouling paint base resin, 5.5 parts of a defoamer, 257.5 parts of talc, 132 parts of ZnO, 37 parts of an anti-settling agent, 33 parts of a black color paste, and 6.6 parts of a blue color paste. The ratio of the fluorinated hydroxyl acrylic resin to the polyester resin is 1:1-1:9, and the black and blue color pastes are commercially available products.

[0015] The invention discloses the application of the double-crosslinked self-polishing antifouling paint base resin in the preparation of marine antifouling paint.

[0016] Compared with the prior art, the preparation method of the double-crosslinked self-polishing antifouling paint base resin described in the embodiment of the present invention has the following beneficial effects: 1) polyester resin degradation is used as a self-polishing component, and the acrylic resin component and the polyester resin form a double-crosslinked network structure to enhance the mechanical strength of the coating. The double-crosslinked structure can effectively improve the mechanical strength of the resin, enhance the flexibility and impact resistance of the coating, and provide a new idea for the preparation of a new type of anti-collision and high-flexibility antifouling coating; 2) hydroxyethyl methacrylate, methyl methacrylate, butyl acrylate, hexafluorobutyl methacrylate are reacted with azobisisobutyl acrylate to form a double-crosslinked network structure. A fluorinated hydroxyl acrylic resin is prepared by a one-step free radical polymerization reaction in a nitrogen environment using nitrile as an initiator. The hydroxyl groups on the side chains of the non-hydrolyzable acrylic resin can react with the isocyanate groups of the curing agent to form a cross-linked network structure, so that the poly (lactide-caprolactone) polyester resin prepared by the ring-opening polymerization of lactide and caprolactone can still maintain the mechanical properties of the coating as a whole in the cross-linked acrylic resin network system after hydrolysis; 3) The hydroxyl groups on the side chains react with the polyisocyanate-based curing agent to form a double cross-linked network structure, thereby improving the flexibility and elongation at break of the resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FT-IR spectra of OHFR resin and BP polyester prepared in Example 1 of the present invention;

[0018] Figure 2 This is a graph showing the tensile properties of BPPA resins prepared in Examples 4-6 of the present invention;

[0019] Figure 3 The figures show the actual sea immersion fouling of the corresponding coatings of Examples 4-6 of the present invention and the control group. DETAILED DESCRIPTION

[0020] To make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is made in conjunction with the accompanying drawings. The technical features of the embodiments of the present invention can be combined with each other without conflict.

[0021] Marine antifouling materials are the first line of defense to protect marine equipment from marine biocorrosion and are an important guarantee for ensuring the smooth development of human marine development and utilization activities. The base material of traditional self-polishing antifouling coatings is usually a linear resin of acrylic acid or methacrylate, whose side chains are hydrolyzable and mainly composed of copper acrylate, zinc acrylate and acrylic silicone resin. Zinc oxide, cuprous oxide and auxiliary antifouling agents such as hydroxypyridine copper sulfate and hydroxypyridine copper thione constitute the antifouling filler. Since the acrylic acid ester resin base material is a linear resin with hydrolyzable side chains, mainly composed of copper acrylate, zinc acrylate and acrylic silicone resin, the surface of the coating immersed in seawater is polished and detached under the hydrolysis of the hydrolyzable polymer to release the antifouling filler inside the coating, achieving an antifouling effect. However, the above-mentioned coating is prone to brittle cracking or falling off when subjected to external force, friction or deformation of the substrate, leading to failure; and the main chain of the single polyester resin is degradable and the degradation rate is too fast in seawater, which not only makes the final coating less hard and easily degrades and detaches from the surface, but also shortens the antifouling period. To this end, the applicant proposes the following technical solution:

[0022] Example 1

[0023] A double-crosslinked self-polishing antifouling paint base resin, comprising a fluorinated hydroxyl acrylic resin and a poly(lactide-caprolactone) polyester resin in a mass ratio of 9:1;

[0024] The synthetic route of the fluorinated hydroxyl acrylic resin is:

[0025] #timg#

[0026] Prepared by the following method:

[0027] S1. Weigh hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), butyl acrylate (BA), hexafluorobutyl methacrylate (FMA), and azobisisobutyronitrile (AIBN) in a mass ratio of 237.3:284.7:54:24:12.5 (see Table 1 below), and add a certain amount of xylene to fully dissolve them to form a mixed solution;

[0028] Table 1 Raw material formula and molecular weight and molecular weight distribution of resin

[0029] Initiator content (mol%) Addition time (h) Reaction temperature (℃) MMA / BA / FMA / HEMA / AIBN (g) <![CDATA[M w (g / mol)]]> PDI 1.5 3 90 237.3 / 284.7 / 54 / 24 / 12.5 4792 1.58

[0030] S2. Add a certain amount of xylene to a reaction vessel and heat to 90°C. Then, uniformly add the mixed solution obtained in step S1 dropwise to the reaction vessel over 3 hours. Then, add a small amount of AIBN-xylene solution dropwise over 20 minutes, and continue the reaction for 3 hours. As an example of the present invention, the reaction vessel is a four-necked flask equipped with a thermometer and a constant pressure dropping funnel.

[0031] The synthetic route of the poly (lactide-caprolactone) polyester resin is:

[0032] #timg#

[0033] Prepared by the following method:

[0034] Using xylene as the solvent, lactide LA and caprolactone CL at a molar ratio of 1:1 are added to a reaction vessel, stirred, and heated to 130°C. After the lactide LA is completely dissolved, 0.1 wt% of stannous octoate (Sn Oct2) is added as a catalyst. Mechanical stirring is then performed at 130°C for 6 hours to obtain the product. The reaction vessel is preferably a four-necked flask equipped with a thermometer and a constant pressure dropping funnel.

[0035] Example 2

[0036] A double-crosslinked self-polishing antifouling paint base resin, comprising a fluorinated hydroxyl acrylic resin and a poly(lactide-caprolactone) polyester resin in a mass ratio of 7:3;

[0037] The synthetic route of the fluorinated hydroxyl acrylic resin is:

[0038] #timg#

[0039] Prepared by the following method:

[0040] S1. Weigh HEMA, MMA, BA, FMA, and AIBN in a mass ratio of 237.3:284.7:54:24:12.5 (see Table 1 below), and add a certain amount of xylene to fully dissolve them to form a mixed solution;

[0041] Table 1 Raw material formula and molecular weight and molecular weight distribution of resin

[0042] Initiator content (mol%) Addition time (h) Reaction temperature (℃) MMA / BA / FMA / HEMA / AIBN (g) <![CDATA[M w (g / mol)]]> PDI 1.5 3.5 95 237.3 / 284.7 / 54 / 24 / 12.5 4792 1.58

[0043] S2. Add a certain amount of xylene to a reaction vessel and heat to 95°C. Then, uniformly add the mixed solution obtained in step S1 dropwise to the reaction vessel over 3.5 hours. Then, add a small amount of AIBN-xylene solution dropwise over 20 minutes, and continue the reaction for 2.5 hours. As an example of the present invention, the reaction vessel is a four-necked flask equipped with a thermometer and a constant pressure dropping funnel.

[0044] The synthetic route of the poly (lactide-caprolactone) polyester resin is:

[0045] #timg#

[0046] Prepared by the following method:

[0047] Using xylene as the solvent, lactide LA and caprolactone CL at a molar ratio of 1.2:1 are added to a reaction vessel. The mixture is stirred and heated to 135°C. After the lactide LA is completely dissolved, a 0.12% by mass fraction of stannous octoate (SnOct2) catalyst is added. The temperature is maintained at 135°C with mechanical stirring for 4 hours to obtain the product. The reaction vessel is preferably a four-necked flask equipped with a thermometer and a constant pressure dropping funnel.

[0048] Fourier infrared test of fluorinated hydroxyl acrylic resin (OHFR) and poly (lactide-caprolactone) polyester resin (BP polyester) Figure 1 FT-IR was used to characterize the molecular structure of OHFR resin and BP polyester. For OHFR resin, 3523 cm -1 The absorption peak at 1183 cm is the characteristic peak of -OH, while the absorption peak at 1183 cm -1 The peak at 1725 cm corresponds to the stretching vibration peak of CF; -1 The stretching vibration peak corresponding to the carbonyl group is 2952 cm -1 and 2870cm -1 The 3517cm-1 peak is the stretching vibration absorption peak of methyl and methylene, which corresponds to the basic functional group characteristic peak of acrylic resin. For BP polyester resin, 3517cm-1 -1 The stretching vibration peak corresponding to -OH is 2937 cm -1 and 2880cm -1 The stretching vibration absorption peaks of methyl and methylene are at 1592 cm -1 The corresponding position is the deformation vibration of NH.

[0049] Example 3

[0050] A double-crosslinked self-polishing antifouling paint base resin, comprising a fluorine-containing hydroxyl acrylic resin and a poly (lactide-caprolactone) polyester resin in a mass ratio of 1:1;

[0051] The synthetic route of the fluorinated hydroxyl acrylic resin is:

[0052] #timg#

[0053] Prepared by the following method:

[0054] S1. Weigh HEMA, MMA, BA, FMA, and AIBN in a mass ratio of 237.3:284.7:54:24:12.5 (see Table 1 below), and add a certain amount of xylene to fully dissolve them to form a mixed solution;

[0055] Table 1 Raw material formula and molecular weight and molecular weight distribution of resin

[0056] Initiator content (mol%) Addition time (h) Reaction temperature (℃) MMA / BA / FMA / HEMA / AIBN (g) <![CDATA[M w (g / mol)]]> PDI 1.5 4.5 85 237.3 / 284.7 / 54 / 24 / 12.5 4792 1.58

[0057] S2. Add a certain amount of xylene to a reaction vessel and heat to 85°C. Then, uniformly add the mixed solution obtained in step S1 dropwise to the reaction vessel over 4.5 hours. Then, add a small amount of AIBN-xylene solution dropwise over 20 minutes, and continue the reaction for 4.5 hours. As an example of the present invention, the reaction vessel is a four-necked flask equipped with a thermometer and a constant pressure dropping funnel.

[0058] The synthetic route of the poly (lactide-caprolactone) polyester resin is:

[0059] #timg#

[0060] Prepared by the following method:

[0061] Using xylene as the solvent, lactide LA and caprolactone CL at a molar ratio of 1:1.2 are added to a reaction vessel. The mixture is stirred and heated to 125°C. After the lactide LA is completely dissolved, 0.08% by mass of stannous octoate (Sn Oct2) is added as a catalyst. The temperature is maintained at 125°C with mechanical stirring for 8 hours to obtain the product. The reaction vessel is preferably a four-necked flask equipped with a thermometer and a constant pressure dropping funnel.

[0062] The double-crosslinked self-polishing antifouling paint base resin of Examples 1-3 was cured with a commercially available N3390 curing agent at a molar ratio of 1:1 hydroxyl:isocyanate, and dibutyltin dilaurate as a catalyst (0.5% of the total mass) to prepare a polyester-based polyurethane (BPPA) resin. The flexibility, impact resistance, and pencil hardness of the BPPA resin were tested. The results are shown in Table 4. The tensile properties of the BPPA resin were also tested using a universal tensile testing machine. The results are shown in Table 5 and Figure 2 .

[0063] Table 4 Effect of mixing ratio on the flexibility, impact resistance and hardness of the final coating

[0064] Sample source Bending diameter (mm) Impact resistance (cm) hardness Example 1 ≤1mm 50 5B Example 2 ≤1mm 50 2B Example 3 ≤1mm 50 B

[0065] Table 5 Effect of mixing ratio on tensile strength, elongation at break and modulus of the final coating

[0066] Sample source Tensile strength (MPa) Elongation at break (%) Elastic modulus (MPa) Example 1 0.17 62.52 0.28 Example 2 0.31 127.31 0.30 Example 3 0.52 181.96 0.36

[0067] Examples 4-6

[0068] The composition and dosage of Table 6 were used to prepare the coating component B in a conventional manner, with a polyester-based antifouling coating as a control. The commercially available N3390 curing agent was used as the coating component A, and the molar ratio of hydroxyl to isocyanate was controlled to be 1:1 for curing to form a coating.

[0069] Table 6 Composition and dosage of component B in coating

[0070] Raw materials (g) Example 4 Example 5 Example 6 BP polyester 291.2 226.4 161.8 OHFR resin 33 99 165 defoaming agent 5.5 5.5 5.5 Phthalocyanine blue paste 6.6 6.6 6.6 Carbon black paste 33 33 33 Mancozeb 56 56 56 Diuron 20 20 20 Chlorothalonil 79 79 79 talcum powder 257.5 257.5 257.5 ZnO 132 132 132 anti-settling agent 37 37 37 Xylene 32 32 32

[0071] The coatings prepared in Examples 4-6 and the control group were applied to the surface of a carbon steel substrate. The flexibility of the coatings was tested using a paint film flexibility mandrel tester BGD560 according to GB / T 1731-2020. The impact resistance of the coatings was tested using a paint film impactor QOJ-100 according to the GB / T 1732-2020 test standard. The pencil hardness of the coatings was tested using a portable pencil hardness tester QHQ-A according to the GB / T 6739-2006 test standard. The adhesion of the coatings was tested using a pull-off adhesion tester Defelsko-AT according to the GB / T 5210-2006 test standard. The test data are shown in Table 7.

[0072] Table 7 Mechanical properties of antifouling coatings prepared in Examples 4-6

[0073] Paint Source Flexibility (mm) Impact resistance (cm) hardness Adhesion (MPa) Example 4 ≤1mm 50 5B 1.3 Example 5 ≤1mm 50 4B 1.8 Example 6 ≤1mm 50 2B 2.3 comparison ≤1mm 50 5B 0.8

[0074] As shown in Table 7, the polyester-based antifouling coating used as a control has a low adhesion of only 0.8 MPa on the carbon steel substrate. However, the base resin of the dual-crosslinked self-polishing antifouling paint prepared in Examples 4-6 of the present application is a non-hydrolyzable acrylic resin, the hydroxyl groups of which can react with the isocyanate groups of the curing agent to form a cross-linked network structure. As a result, after the polyester resin is hydrolyzed, the overall coating can still maintain mechanical properties in the cross-linked acrylic resin network system, which is significantly better than the control group.

[0075] The coatings prepared in Examples 4-6 were applied to the surface of epoxy boards, and epoxy boards without any coating were used as blank controls. The antifouling performance of the antifouling coatings was evaluated according to the GB / T 5370-2007 test standard. The specific operation was as follows: the epoxy resin sample (400mm×300mm×3mm) was polished with 800-grit sandpaper, and then the connecting paint 725-HB53-1 was applied. The dry film thickness of the connecting paint was about 80μm. The antifouling coating prepared in Examples 4-6 was then applied. The dry film thickness was about 60μm. After natural air drying, the antifouling coating sample was obtained. The prepared antifouling coating sample was immersed in an artificial floating raft in the waters of Xiamen, with a water depth of 3-5 meters. The results are shown in FIG. Figure 3 .

[0076] Depend on Figure 3 It can be seen that the coatings prepared in Examples 4-6 of the present application achieve underwater self-polishing through the degradation of the main chain of the polyester resin, and enhance the mechanical properties of the resin by forming an interconductive network structure between the fluorinated hydroxyl acrylic resin and the polyester resin chain segments. The crosslinking degree and degradation rate of the resin can be controlled by regulating the ratio of the two resins and the hydroxyl density. After immersion in seawater for 120 days, basically no fouling occurs, indicating that it has a good antifouling effect, among which the effects of Examples 5-6 are better than Example 4; if a polyester resin-based antifouling coating without adding an acrylic resin component is used, severe fouling will occur after immersion in seawater for 120 days. This is because the polyester-based antifouling coating undergoes segment degradation in seawater, and after degradation, the entire piece is easily detached, resulting in rapid failure of the coating.

[0077] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A method for preparing a double-crosslinked self-polishing antifouling paint base resin, characterized in that: The method comprises component B, wherein component B comprises a fluorine-containing hydroxyl acrylic resin and a polyester resin in a mass ratio of 1:1 to 1:9, wherein the structural formula of the fluorine-containing hydroxyl acrylic resin is: The structural formula of the polyester resin is: 。 2. The method for preparing a double-crosslinked self-polishing antifouling paint base resin according to claim 1, wherein: The double-crosslinked self-polishing antifouling paint base resin further comprises component A, which is an isocyanate-containing curing agent, wherein the molar ratio of the hydroxyl group of component B to the isocyanate group of component A is 0.8-1.2:

1.

3. The method for preparing a double-crosslinked self-polishing antifouling paint base resin according to claim 1, wherein: The fluorinated hydroxyl acrylic resin is prepared by the following method: S1, HEMA, MMA, BA, FMA, and AIBN are weighed according to the amount, and then a certain amount of solvent is added to fully dissolve them to form a mixed solution; S2, a certain amount of solvent is added to a reaction container and heated to 85-95° C., and the mixed solution of step S1 is uniformly added dropwise to the reaction container over 2.5-3.5 hours under stirring, and then a small amount of AIBN-containing solution is added dropwise, and the reaction is continued for 2-4 hours to obtain the fluorinated hydroxyl acrylic resin.

4. The method for preparing a double-crosslinked self-polishing antifouling paint base resin according to claim 3, wherein: In step S1, the mass ratio of hexafluorobutyl methacrylate (FMA) to the total monomer mass is 5% to 20%, the mass ratio of azobisisobutyronitrile (AIBN) to the total monomer mass is 0.5% to 2%, the mass ratio of methyl methacrylate to butyl methacrylate is 65:35 to 55:45, and the content of hydroxyethyl methacrylate is 5% to 15% of the total monomer mass. The dropwise addition rate of the mixed solution in step S2 is 50 to 90 g / h, and the stirring speed is 400 to 800 rpm.

5. The method for preparing a double-crosslinked self-polishing antifouling paint base resin according to claim 1, characterized in that: The polyester resin is prepared according to the following method: adding an appropriate amount of solvent to a reaction vessel, then adding lactide and caprolactone at a molar ratio of 0.8-1.2:1, heating to 120-135°C until the lactide is completely dissolved, then adding 0.08-0.1wt% of a catalyst, maintaining the temperature at 120-135°C and stirring for 5-7 hours to obtain the polyester resin.

6. The method for preparing a double-crosslinked self-polishing antifouling paint base resin according to claim 5, characterized in that: The catalyst is dibutyltin dilaurate.

Images