A liquid-phase functional urethane antifouling coating, its preparation method and application

Abstract

This invention discloses a liquid-phase functional urethane antifouling coating, its preparation method, and its application. The preparation method includes the following steps: S1. Mixing monohydroxy-terminated polydimethylsiloxane and polypropylene glycol and removing water to obtain solution A; S2. Dissolving hexamethylene diisocyanate trimer in xylene to obtain solution B; slowly adding solution B dropwise to solution A while continuously stirring; S3. After the addition is complete, heating the reaction to 80-85°C and continuously stirring to ensure a complete reaction, finally obtaining prepolymer C; S4. Adding curing agent polyaspartic acid ester, leveling agent, and defoamer to solution C, and stirring to obtain solution D; S5. Applying solution D to the surface of a substrate and curing at room temperature for 2 hours to obtain a liquid-phase functional urethane antifouling coating. The antifouling coating of this invention can cure at room temperature, is environmentally friendly, inhibits the adhesion of fouling organisms, and has good anti-icing properties.

Description

Technical Field

[0001] This invention relates to the field of marine antifouling coating technology, and in particular to a liquid-phase functional urethane antifouling coating, its preparation method, and its application. Background Technology

[0002] Marine biofouling is a well-known problem; within a short period, ship hulls and other artificial underwater surfaces inevitably become infested with various marine organisms. Marine biofouling causes serious economic and environmental problems. Effectively controlling biofouling is crucial, and antifouling coatings are currently an effective means of suppressing it. Among antifouling coatings, smooth liquid-injected surfaces are a typical example, but the lubricant in these coatings is easily depleted; when subjected to large-area damage, the coating loses a significant amount of lubricant, thus losing its performance; although the lubricant in the coating is harmless, its high stability poses a potential danger to the marine environment. Therefore, there is a need to develop an antifouling coating preparation technology that releases no lubricant but possesses a lubricant-like surface, which can be applied to the surfaces of ships, floating platforms, underwater vehicles, and other underwater equipment to suppress biofouling.

[0003] For lubricant-free release coatings, Zuo Biao et al. proposed a method for preparing ultra-high graft density polymer molecular brushes in Chinese patent CN109400827A, entitled "A Preparation Method of Ultra-High Graft Density Polymer Molecular Brushes". This method first prepares a SiO2 / Si substrate, then self-assembles an initiator monolayer on the SiO2 / Si substrate surface, and finally cures the polymer brush at 100℃ for 3 hours. However, it cannot be cured at room temperature, and the use of SiO2 / Si substrates limits its application on other substrates. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a liquid-phase functional urethane antifouling coating, its preparation method and application. This liquid-phase functional urethane antifouling coating can be cured at room temperature, is environmentally friendly, can inhibit the adhesion of fouling organisms, and has good anti-icing properties.

[0005] The technical solution adopted is as follows:

[0006] The present invention discloses a method for preparing a liquid-phase functional urethane antifouling coating, comprising the following steps:

[0007] S1. Hydroxyl-terminated polydimethylsiloxane and polypropylene glycol are mixed and then dehydrated to obtain solution A;

[0008] S2. Dissolve the hexamethylene diisocyanate trimer in xylene to obtain solution B; slowly add solution B dropwise to solution A while stirring continuously during the dropwise addition process;

[0009] S3. After the addition is complete, heat the reaction to 80-85℃ and stir continuously to ensure the reaction is complete, and finally obtain prepolymer C;

[0010] S4. Add curing agent polyaspartic acid ester, leveling agent and defoamer to C, and stir to obtain solution D;

[0011] S5. Apply D to the substrate surface and cure at room temperature for 2 hours to obtain a liquid-phase functional urethane antifouling coating.

[0012] Furthermore, in S1, the molar ratio of monohydroxy-terminated polydimethylsiloxane, polypropylene glycol, and hexamethylene diisocyanate trimer in S2 is 0.1-0.5:0.25:1.

[0013] Furthermore, in S1, water is removed at 100-110℃ for 2-3 hours.

[0014] Furthermore, in S2, the total amount of xylene is 30%-50% of the total mass of the monohydroxy-terminated polydimethylsiloxane in S1 and the hexamethylene diisocyanate trimer in S2.

[0015] Furthermore, in S2, the dropping rate is 50-150 g / h, and the dropping continues for 30-40 minutes.

[0016] Furthermore, continue stirring for 3-4 hours to ensure a complete reaction.

[0017] Furthermore, in S4, the mass of the defoamer and the leveling agent are 0.1% of the mass of the S3 prepolymer and the total mass of the S4 polyaspartic ester, respectively.

[0018] Further, in S4, stir at 2000-2500 rpm for 5-10 minutes to obtain solution D.

[0019] In this invention, the leveling agent and defoamer can be commercially available, including but not limited to, for example, the leveling agent can be one of the commercially available BYK-306, BYK-307, and BYK-330 from Germany, and the defoamer can be one of the commercially available BYK-066N, BYK-141, BYK-071, and BYK-060N from Germany.

[0020] The present invention provides a liquid-phase functional urethane antifouling coating, which is prepared by the preparation method described above.

[0021] The liquid-phase functional urethane antifouling coating prepared by the described method is used for surface protection of underwater equipment, including ships, floating platforms, and underwater vehicles. Specifically, the prepared antifouling coating can be applied to the surface of underwater equipment such as ships, floating platforms, and underwater vehicles to inhibit biofouling.

[0022] In the above technical solutions,

[0023] This invention relates to an antifouling coating made by chemically grafting flexible, single-hydroxyl-terminated polydimethylsiloxane onto urethane. The grafted, flexible polydimethylsiloxane chains possess liquid-like smoothness and exhibit a high migration rate. This rapid perturbation of the flexible chains inhibits biofouling adhesion, thus improving the coating's antifouling performance. Furthermore, the glass transition temperature of the polydimethylsiloxane flexible chains is -127°C, allowing numerous repeating Si-O bonds to remain in a flexible state even at low temperatures. The rapid perturbation of these flexible chain segments can interfere with ice crystal formation, thus providing anti-icing properties. Simultaneously, the coating is environmentally friendly.

[0024] The structural formula of monohydroxyl-terminated polydimethylsiloxane is as follows:

[0025]

[0026] Where n is the degree of polymerization, usually 10-1000, and R is methyl or ethyl.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. This invention introduces environmentally friendly and low-cost monohydroxy-terminated polydimethylsiloxane flexible chains into the field of urethane antifouling coatings, which has certain application prospects.

[0029] 2. The low surface energy smoothness of polydimethylsiloxane is achieved by utilizing the flexible chain of monohydroxy-terminated polydimethylsiloxane, thereby inhibiting the adhesion of fouling organisms. The antifouling performance of the resin can be controlled by controlling the content of monohydroxy-terminated polydimethylsiloxane and hexamethylene diisocyanate trimer.

[0030] 3. The perturbation behavior of the flexible chain of monohydroxy-terminated polydimethylsiloxane can be used to suppress the formation of ice crystal nuclei. The anti-icing performance of the resin can be controlled by controlling the content of monohydroxy-terminated polydimethylsiloxane.

[0031] 4. The polymer resin (solution D) has good compatibility with the solvent and can be stored for a long time without deterioration or curing, which facilitates the application of subsequent marine antifouling coatings or the formulation of marine antifouling coatings.

[0032] 5. The polymer resin (solution D) can be cured at room temperature for two hours. Detailed Implementation

[0033] The present invention will be described in detail below through specific embodiments. However, the uses and purposes of these exemplary embodiments are only for illustrating the present invention and do not constitute any limitation on the actual protection scope of the present invention, nor are they intended to limit the protection scope of the present invention to these embodiments.

[0034] Example 1

[0035] This embodiment of a liquid-phase functional urethane antifouling coating is prepared through the following steps:

[0036] (1) Add 14.2g of monohydroxy-terminated polydimethylsiloxane and 25g of PPG (i.e., polypropylene glycol) to a three-necked flask and...

[0037] Vacuum dehydration at 110℃ for 2 hours.

[0038] (2) Dissolve 60g of hexamethylene diisocyanate trimer in 40g of xylene, and slowly add the solution dropwise to a three-necked flask at room temperature for 30 minutes while stirring continuously at a speed of 400 rpm.

[0039] (3) After the addition is complete, the reaction is heated to 80-85℃ and stirred continuously for 3 hours to ensure the reaction is complete, and finally the prepolymer is obtained for subsequent synthesis of antifouling coatings.

[0040] (4) Take 20g of prepolymer, add 12.8g of curing agent polyaspartic acid ester, 0.033g of leveling agent and 0.033g of defoamer, and stir at 2000rpm for 5 minutes.

[0041] (5) Apply the resin to the surface of the substrate and cure at room temperature for 2 hours to obtain a liquid-phase functional urethane antifouling coating. This coating is named PPNP-10.

[0042] Perform the following experiment:

[0043] I. Laboratory Static Inhibition and Desorption Diatom Experiment: The sample from Example 1 was evenly coated onto a glass slide measuring 2.5cm × 3.5cm. A blank glass slide was used as a blank control. The sample slide and the blank glass slide were immersed in two model algae species (Diamondsia spp. and Rhomboidia spp.) for 1 day, 3 days, and 5 days, respectively. After removing the sample, the unattached algae were removed. The algae attachment on the coating was photographed under an optical microscope. Five areas were randomly selected from each coating for photographing. The average number of diatom cells on the blank glass slide and the sample from Example 1 was calculated using the following formulas (1) and (2):

[0044]

[0045]

[0046] Where K represents the inhibition rate of diatom adhesion, R represents the inhibition rate of diatom detachment, NB represents the average number of diatom cells on the surface of the blank glass slide, N1 represents the average number of diatom cells on the surface of the sample, and N2 represents the average number of diatom cells on the surface of the sample after rinsing.

[0047] II. Anti-icing test: The sample of Example 1 was evenly coated on a glass slide with a size of 2.5cm×3.5cm. A blank glass slide was selected as a blank control. The experiment was conducted using a video optical contact angle measuring instrument at a temperature of -20℃. 5μL of aqueous solution was added to the coating surface to observe the solidification time of the droplet. The solidification time of water on the glass slide was 12s.

[0048] The inhibition rate and desorption rate of *Dysmorpha chinensis* after 5 days were calculated to be 39.14% and 32.71%, respectively, with a delayed freezing time of 40 seconds.

[0049] Example 2

[0050] This embodiment of a liquid-phase functional urethane antifouling coating is prepared through the following steps:

[0051] (1) Add 28.4g of monohydroxy-terminated polydimethylsiloxane and 25g of PPG to a three-necked flask and remove water by vacuuming at 110°C for 2 hours.

[0052] (2) Dissolve 60g of hexamethylene diisocyanate trimer in 45g of xylene, and slowly add the solution dropwise to a three-necked flask at room temperature for 30 minutes while stirring continuously at a speed of 400 rpm.

[0053] (3) After the addition is complete, the reaction is heated to 80-85℃ and stirred continuously for 3 hours to ensure the reaction is complete, and finally the prepolymer is obtained for subsequent synthesis of antifouling coatings.

[0054] (4) Take 20g of prepolymer, add 10.69g of curing agent polyaspartic acid ester, 0.03g of leveling agent and 0.03g of defoamer, and stir at 2000rpm for 5 minutes.

[0055] (5) Apply the resin to the surface of the substrate and cure at room temperature for 2 hours to obtain a liquid-phase functional urethane antifouling coating. This coating is named PPNP-20.

[0056] The inhibition rate and desorption rate of *Dysmorpha chinensis* after 5 days were calculated to be 57.97% and 46.12%, respectively, with a delayed freezing time of 44 seconds.

[0057] Example 3

[0058] This embodiment of a liquid-phase functional urethane antifouling coating is prepared through the following steps:

[0059] (1) Add 42.6g of monohydroxy-terminated polydimethylsiloxane and 25g of PPG to a three-necked flask and remove water by vacuum at 110°C for 2 hours.

[0060] (2) Dissolve 60g of hexamethylene diisocyanate trimer in 51g of xylene, and slowly add the solution dropwise to a three-necked flask at room temperature for 30 minutes while stirring continuously at a speed of 400 rpm.

[0061] (3) After the addition is complete, the reaction is heated to 80-85℃ and stirred continuously for 3 hours to ensure the reaction is complete, and finally the prepolymer is obtained for subsequent synthesis of antifouling coatings.

[0062] (4) Take 20g of prepolymer, add 9.05g of curing agent polyaspartic acid ester, 0.029g of leveling agent and 0.029g of defoamer, and stir at 2000rpm for 5 minutes.

[0063] (5) Apply the resin to the surface of the substrate and cure at room temperature for 2 hours to obtain a liquid-phase functional urethane antifouling coating. This coating is named PPNP-30.

[0064] The inhibition rate and desorption rate of *Dysmorpha chinensis* after 5 days were calculated to be 62.75% and 63.73%, respectively, and the delayed freezing time was 86 s.

[0065] Example 4

[0066] This embodiment of a liquid-phase functional urethane antifouling coating is prepared through the following steps:

[0067] (1) Add 56.8g of monohydroxy-terminated polydimethylsiloxane and 25g of PPG to a three-necked flask and remove water by vacuuming at 110°C for 2 hours.

[0068] (2) Dissolve 60g of hexamethylene diisocyanate trimer in 56.72g of xylene, and slowly add the solution dropwise to a three-necked flask at room temperature for 30 minutes, stirring continuously at a speed of 400 rpm.

[0069] (3) After the addition is complete, the reaction is heated to 80-85℃ and stirred continuously for 3 hours to ensure the reaction is complete, and finally the prepolymer is obtained for subsequent synthesis of antifouling coatings.

[0070] (4) Take 20g of prepolymer, add 7.73g of curing agent polyaspartic acid ester, 0.027g of leveling agent and 0.027g of defoamer, and stir at 2000rpm for 5 minutes.

[0071] (5) Apply the resin to the surface of the substrate and cure at room temperature for 2 hours to obtain a liquid-phase functional urethane antifouling coating. This coating is named PPNP-40.

[0072] The inhibition rate and desorption rate of *Dysmorpha chinensis* after 5 days were calculated to be 72.39% and 73.13%, respectively, with a delayed freezing time of 100 s.

[0073] Example 5

[0074] This embodiment of a liquid-phase functional urethane antifouling coating is prepared through the following steps:

[0075] (1) Add 71g of monohydroxy-terminated polydimethylsiloxane and 25g of PPG to a three-necked flask and remove water by vacuuming at 110°C for 2 hours.

[0076] (2) Dissolve 60g of hexamethylene diisocyanate trimer in 62g of xylene, and slowly add the solution dropwise to a three-necked flask at room temperature for 30 minutes while stirring continuously at a speed of 400 rpm.

[0077] (3) After the addition is complete, the reaction is heated to 80-85℃ and stirred continuously for 3 hours to ensure the reaction is complete, and finally the prepolymer is obtained for subsequent synthesis of antifouling coatings.

[0078] (4) Take 20g of prepolymer, add 6.65g of curing agent polyaspartic acid ester, 0.026g of leveling agent and 0.026g of defoamer, and stir at 2000rpm for 5 minutes.

[0079] (5) Apply the resin to the surface of the substrate and cure at room temperature for 2 hours to obtain a liquid-phase functional urethane antifouling coating. This coating is named PPNP-50.

[0080] The inhibition rate and desorption rate of *Dysmorpha chinensis* after 5 days were calculated to be 79.15% and 82.86%, respectively, and the delayed freezing time was 207 s.

[0081] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a liquid-like functional urethane antifouling coating, characterized by, Includes the following steps: S1. Hydroxyl-terminated polydimethylsiloxane and polypropylene glycol are mixed and then dehydrated to obtain solution A; S2. Dissolve the hexamethylene diisocyanate trimer in xylene to obtain solution B; slowly add solution B dropwise to solution A while stirring continuously; the molar ratio of monohydroxyl-terminated polydimethylsiloxane, polypropylene glycol and hexamethylene diisocyanate trimer is 0.1-0.5:0.25:1; S3. After the addition is complete, heat the reaction to 80-85℃ and stir continuously to ensure the reaction is complete, finally obtaining prepolymer C; S4. Add curing agent polyaspartic acid ester, leveling agent, and defoamer to C, and stir to obtain solution D; S5. Apply D to the substrate surface and cure at room temperature for 2 hours to obtain a liquid-phase functional urethane antifouling coating.

2. The method for preparing a quasi-liquid functional urethane antifouling coating according to claim 1, characterized by, In S1, water is removed at 100-110℃ for 2-3 hours.

3. The method for preparing the liquid-phase functional urethane antifouling coating according to claim 1, characterized in that, In S2, the total amount of xylene is 30%-50% of the total mass of monohydroxy-terminated polydimethylsiloxane in S1 and hexamethylene diisocyanate trimer in S2.

4. The method for preparing the liquid-phase functional urethane antifouling coating according to claim 1, characterized in that, In S2, the dropping rate is 50-150 g / h, and the dropping continues for 30-40 minutes.

5. The method for preparing the liquid-phase functional urethane antifouling coating according to claim 1, characterized in that, Continue stirring for 3-4 hours to ensure a complete reaction.

6. The method for preparing the liquid-phase functional urethane antifouling coating according to claim 1, characterized in that, In S4, the defoamer and leveling agent are 0.1% of the mass of the S3 prepolymer and the total mass of the S4 polyaspartic acid ester, respectively.

7. The method for preparing the liquid-phase functional urethane antifouling coating according to claim 1, characterized in that, In S4, stir at 2000-2500 rpm for 5-10 minutes to obtain solution D.

8. A liquid-phase functional urethane antifouling coating, characterized in that, It is prepared by any of the preparation methods described in claims 1-7.

9. The application of the liquid-phase functional urethane antifouling coating prepared by any of the preparation methods described in claims 1-7 in the surface protection of equipment including ships, floating work platforms, and underwater vehicles.

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