A soil-resistant polyurethane coating and a method for producing the same

Abstract

The application relates to the technical field of coatings, and discloses an anti-fouling polyurethane coating and a production method thereof.The polyurethane coating comprises the following raw materials: isophorone diisocyanate, polytetrahydrofuran ether diol, an organic tin catalyst, anti-fouling chitosan, 1,4-butanediol, triethylamine, antibacterial nanosheets, deionized water and a defoaming agent.The anti-fouling chitosan and the antibacterial nanosheets are added to the preparation process of the polyurethane coating, so that the prepared coating layer has excellent anti-fouling performance, wear resistance and antibacterial capacity, is not prone to breakage during use, has the stability of a low-surface-energy interface, does not need to be cleaned frequently, can meet the use requirements in various environments, and has a long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coatings, in particular to an anti-fouling polyurethane coating and a production method thereof. BACKGROUND

[0002] As an important polymer material, polyurethane coating has excellent adhesion and flexibility, and is widely used in the fields of building decoration, furniture manufacturing and automobile industry. However, with the increasing requirements of modern industry for material performance, the traditional polyurethane coating has exposed many technical bottlenecks in the long-term application process, especially in the aspects of anti-fouling and wear resistance. In actual use, the surface of the coating formed after the curing of the polyurethane coating is easy to adsorb dust particles, oily pollutants and dyed liquids in the air, and needs to be cleaned frequently. However, frequent cleaning will cause the surface of the polyurethane coating to be scratched, affecting the service life of the polyurethane coating. In addition, since the polyurethane coating does not have antibacterial effect, it greatly limits its application boundary. In the environment with high hygiene requirements such as medical facilities and food processing equipment, the general polyurethane coating does not have the ability to inhibit the growth of microorganisms. In a humid environment, the surface of the coating is easy to form a breeding ground for bacteria and mold, which not only causes pollution but also serves as a medium for disease transmission, affecting the safety of use.

[0003] In order to solve the above problems, the patent with publication number CN115340814B discloses a preparation and application of a cationic polyurethane antibacterial coating. A kind of imidazole cationic aromatic diol polyurethane chain extender diethanolamine-di (phenylimidazole salt amido) s-triazine compound is synthesized by using phenylimidazole, chloroethylamine hydrochloride and diethanolamine-s-triazine as reactants, and participates in the chain extension reaction of polyurethane. The polyurethane hard segment obtained by polymerization contains rigid aromatic ring and s-triazine ring structure. Although this patent improves the thermal stability and mechanical comprehensive performance of polyurethane by preparing a small molecule chain extender, and also endows the polyurethane coating with excellent antibacterial performance, it does not improve the anti-fouling performance of the polyurethane coating. Because the structure contains hydrophilic groups, it may cause oil stains to adhere to the surface of the coating, which needs to be cleaned frequently in actual use, otherwise it will affect the stability of the low surface energy interface on the surface of the coating and the long-term antibacterial effect, and increase the labor cost. SUMMARY

[0004] The present application aims to provide an anti-fouling polyurethane coating and a production method thereof, which solves the following technical problems: (1) the anti-fouling ability of ordinary polyurethane coating is poor, and the formed coating needs to be cleaned frequently; (2) the wear resistance of ordinary polyurethane coating is generally poor and easy to scratch; (3) ordinary polyurethane coating does not have antibacterial ability, which limits its application field.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] An antifouling polyurethane coating comprises the following raw materials in parts by weight: 20-25 parts isophorone diisocyanate, 15-20 parts polytetrahydrofuran ether diol, 0.3-0.5 parts organotin catalyst, 5-8 parts antifouling guar gum, 3-5 parts 1,4-butanediol, 1-2 parts triethylamine, 4-6 parts antibacterial nanosheets, 80-100 parts deionized water, and 2-3 parts defoamer.

[0007] Furthermore, the organotin catalyst is either dibutyltin dilaurate or stannous octoate; the neutralizing agent is triethylamine; and the defoamer is dimethyl silicone oil.

[0008] Furthermore, the preparation method of the antifouling gel includes the following steps:

[0009] S1: Place guar gum in acetone, mix and stir thoroughly, introduce nitrogen gas, add dimethylvinylchlorosilane, heat and reflux to react, collect the product to obtain ethylene-modified guar gum.

[0010] S2: Ethylated guar gum is placed in anhydrous ethanol, perfluorohexyl ethyl acrylate and an initiator are added, the temperature is raised to 55-65℃, the reaction is carried out for 6-8 hours, the product is collected after vacuum distillation, and antifouling guar gum is obtained.

[0011] In this scheme, through a reflux reaction, the hydroxyl groups in the gellan gum structure react with the silanol groups in the dimethylvinylchlorosilane structure, introducing alkenyl and organosilicon into the gellan gum structure to obtain ethylene-based gellan gum. Then, under the action of an initiator, the alkenyl groups in the ethylene-based gellan gum structure undergo a free radical polymerization reaction with the alkenyl groups in the perfluorohexyl ethyl acrylate structure to obtain an antifouling gellan gum. This antifouling gellan gum structure contains both organofluorine and organosilicon. Fluorine atoms have extremely low surface energy, making it difficult for stains to adhere to the coating surface. Organosilicon is hydrophobic, which can reduce the surface energy of the material and has good chemical stability. Combining organofluorine and organosilicon can greatly reduce the surface energy of the coating, giving it excellent antifouling ability. At the same time, using gellan gum as a polymer backbone, it can participate in the preparation process of polyurethane coatings, exhibiting excellent compatibility. Embedding small molecules of organofluorine and organosilicon into the polymer backbone forms a protective effect, making it difficult for the effective components to migrate during actual use, thus obtaining a longer-lasting antifouling effect.

[0012] Furthermore, in step S1, the heating and reflux reaction time is 12-18 hours.

[0013] Further, in step S2, the initiator is either azobisisobutyronitrile or azobisisoheptanenitrile.

[0014] Furthermore, the method for preparing the antibacterial nanosheets includes the following steps:

[0015] SS1: Papyrrolidone and 4-dimethylaminobenzoyl chloride were placed in chloroform, a catalyst was added, and the mixture was stirred thoroughly for 6-8 hours. After filtration and separation, the mixture was washed, vacuum dried, soaked in deionized water for 20-30 minutes, and vacuum dried again. The product was then collected to obtain modified palyrrolidone.

[0016] SS2: Modified palygorskite and 2,3-epoxypropyltrimethylammonium chloride were placed in anhydrous ethanol, ultrasonically dispersed for 10-15 min, heated to react, filtered, washed, and the product was collected to obtain antibacterial nanosheets.

[0017] In this method, under the action of a catalyst, the hydroxyl groups on the surface of palygorskite interact with the acyl chloride groups in the 4-dimethylaminobenzoyl chloride structure to obtain modified palygorskite. Then, through a heated reaction, the tertiary amines on the surface of the modified palygorskite undergo a quaternization reaction with the epoxy groups in the 2,3-epoxypropyltrimethylammonium chloride structure to obtain antibacterial nanosheets containing bisquaternary ammonium groups. These antibacterial nanosheets possess a unique layered structure, effectively isolating pollutants and enhancing the antifouling ability of the coating. Furthermore, the introduction of nanoparticles effectively improves the wear resistance of the coating, making it less prone to wear and extending its service life. Simultaneously, the bisquaternary ammonium groups introduced on its surface effectively disrupt bacterial cell membranes and interact with intracellular proteins, causing protein denaturation and thus damaging cell structure and function, effectively enhancing the antibacterial ability of the coating and enabling it to meet the needs of various environments. Additionally, the active hydroxyl groups introduced on its surface can participate in the preparation process of polyurethane coatings, forming cross-linked structures through chemical bonding, further enhancing the antifouling and wear resistance of the polyurethane coating.

[0018] Furthermore, in step SS1, the catalyst is pyridine.

[0019] Furthermore, in step SS2, the temperature of the heating reaction is 65-75°C, and the time is 6-8 hours.

[0020] A method for producing an antifouling polyurethane coating includes the following preparation steps:

[0021] Step 1: Mix isophorone diisocyanate and polytetrahydrofuran ether diol evenly, introduce nitrogen gas, add organotin catalyst, heat to 50-55℃ and react for 1-1.5h, continue to heat to 75-85℃ and react for 1-1.5h to obtain polyurethane prepolymer;

[0022] Step 2: Add anti-fouling gellan gum and 1,4-butanediol to the polyurethane prepolymer, heat to 80-85℃ and react for 5-6 hours, then cool to 45-55℃ and add neutralizing agent and antibacterial nanosheets. Continue to react for 1-1.5 hours, then add deionized water and defoamer, stir thoroughly for 2-3 hours, and collect the product after natural defoaming to obtain polyurethane coating.

[0023] Furthermore, in step two, the stirring rate for thorough mixing is 300-500 r / min.

[0024] The beneficial effects of this invention are:

[0025] This invention incorporates anti-fouling gel and antibacterial nanosheets into the preparation process of polyurethane coatings, resulting in coatings with excellent anti-fouling properties, wear resistance, and antibacterial capabilities. These coatings are not easily damaged during use, meet the needs of various environments, and have a long service life.

[0026] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a flowchart illustrating the preparation process of the polyurethane coating of this invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The preparation methods of the antifouling gel and antibacterial nanosheets in the following embodiments and comparative examples of the present invention are as follows:

[0031] I. Preparation of anti-fouling colloid

[0032] SS1: Place 3.5g of gellan gum in 60ml of acetone, mix and stir thoroughly, purge with nitrogen, add 3.2g of dimethylvinylchlorosilane, heat and reflux for 12h, collect the product to obtain ethylene-modified gellan gum;

[0033] SS2: Place 4.2g of ethylene-modified kerran gum in 80ml of anhydrous ethanol, add 3.8g of perfluorohexyl ethyl acrylate and 0.1g of azobisisobutyronitrile, heat to 55℃, react for 6h, collect the product after vacuum distillation, and obtain antifouling kerran gum.

[0034] II. Preparation of Antibacterial Nanosheets

[0035] SS1: 3g palygorskite and 2.5g of 4-dimethylaminobenzoyl chloride were placed in 100ml of chloroform, 0.02g of pyridine was added, and the mixture was stirred thoroughly for 6h. After filtration and separation, the product was washed, vacuum dried, soaked in deionized water for 20min, vacuum dried again, and the product was collected to obtain modified palygorskite.

[0036] SS2: 3.6g of modified palygorskite and 3g of 2,3-epoxypropyltrimethylammonium chloride were placed in anhydrous ethanol, ultrasonically dispersed for 10min, heated to 65℃ and reacted for 6h, filtered and washed, and the product was collected to obtain antibacterial nanosheets. Example 1

[0037] Preparation of polyurethane coatings

[0038] Step 1: Mix 20 parts of isophorone diisocyanate and 15 parts of polytetrahydrofuran ether diol evenly, purge with nitrogen, add 0.3 parts of dibutyltin dilaurate, heat to 50°C and react for 1 hour, then continue heating to 75°C and react for 1 hour to obtain polyurethane prepolymer.

[0039] Step 2: Add 5 parts of anti-fouling guar gum and 3 parts of 1,4-butanediol to the polyurethane prepolymer, heat to 80℃ and react for 5 hours, cool to 45℃ and add 1 part of triethylamine and 4 parts of antibacterial nanosheets, continue to react for 1 hour, then add 80 parts of deionized water and 2 parts of dimethyl silicone oil, stir at 300 r / min for 2 hours, collect the product after natural defoaming to obtain the polyurethane coating. Example 2

[0040] Preparation of polyurethane coatings

[0041] Step 1: Mix 22 parts of isophorone diisocyanate and 17 parts of polytetrahydrofuran ether diol evenly, purge with nitrogen, add 0.4 parts of dibutyltin dilaurate, heat to 53℃ and react for 1.2h, then continue heating to 80℃ and react for 1.2h to obtain polyurethane prepolymer;

[0042] Step 2: Add 7 parts of anti-fouling guar gum and 4 parts of 1,4-butanediol to the polyurethane prepolymer, heat to 83℃ and react for 5.5 hours, cool to 50℃ and add 1.5 parts of triethylamine and 5 parts of antibacterial nanosheets, continue to react for 1.2 hours, then add 90 parts of deionized water and 2.5 parts of dimethyl silicone oil, stir at 400 r / min for 2.5 hours, and collect the product after natural defoaming to obtain the polyurethane coating. Example 3

[0043] Preparation of polyurethane coatings

[0044] Step 1: Mix 25 parts of isophorone diisocyanate and 20 parts of polytetrahydrofuran ether diol evenly, purge with nitrogen, add 0.5 parts of stannous octoate, heat to 55℃ and react for 1.5h, then continue heating to 85℃ and react for 1.5h to obtain polyurethane prepolymer.

[0045] Step 2: Add 8 parts of anti-fouling guar gum and 5 parts of 1,4-butanediol to the polyurethane prepolymer, heat to 85℃ and react for 6 hours, then cool to 55℃ and add 2 parts of triethylamine and 6 parts of antibacterial nanosheets. Continue to react for 1.5 hours, then add 100 parts of deionized water and 3 parts of dimethyl silicone oil, stir at 500 r / min for 3 hours, and collect the product after natural defoaming to obtain the polyurethane coating.

[0046] Comparative Example 1

[0047] Preparation of polyurethane coatings

[0048] Step 1: Mix 22 parts of isophorone diisocyanate and 17 parts of polytetrahydrofuran ether diol evenly, purge with nitrogen, add 0.4 parts of dibutyltin dilaurate, heat to 53℃ and react for 1.2h, then continue heating to 80℃ and react for 1.2h to obtain polyurethane prepolymer;

[0049] Step 2: Add 4 parts of 1,4-butanediol to the polyurethane prepolymer, heat to 83℃ and react for 5.5 h, cool to 50℃ and add 1.5 parts of triethylamine and 5 parts of antibacterial nanosheets, continue to react for 1.2 h, then add 90 parts of deionized water and 2.5 parts of dimethyl silicone oil, stir at 400 r / min for 2.5 h, collect the product after natural defoaming to obtain the polyurethane coating.

[0050] Comparative Example 2

[0051] Preparation of polyurethane coatings

[0052] Step 1: Mix 22 parts of isophorone diisocyanate and 17 parts of polytetrahydrofuran ether diol evenly, purge with nitrogen, add 0.4 parts of dibutyltin dilaurate, heat to 53℃ and react for 1.2h, then continue heating to 80℃ and react for 1.2h to obtain polyurethane prepolymer;

[0053] Step 2: Add 7 parts of anti-fouling guar gum and 4 parts of 1,4-butanediol to the polyurethane prepolymer, heat to 83℃ and react for 5.5 hours, cool to 50℃ and add 1.5 parts of triethylamine and continue reacting for 1.2 hours. Then add 90 parts of deionized water and 2.5 parts of dimethyl silicone oil, stir at 400 r / min for 2.5 hours, and collect the product after natural defoaming to obtain the polyurethane coating.

[0054] Comparative Example 3

[0055] Preparation of polyurethane coatings

[0056] Step 1: Mix 22 parts of isophorone diisocyanate and 17 parts of polytetrahydrofuran ether diol evenly, purge with nitrogen, add 0.4 parts of dibutyltin dilaurate, heat to 53℃ and react for 1.2h, then continue heating to 80℃ and react for 1.2h to obtain polyurethane prepolymer;

[0057] Step 2: Add 7 parts of ethylene-modified guar gum and 4 parts of 1,4-butanediol to the polyurethane prepolymer, heat to 83℃ and react for 5.5 h, cool to 50℃ and add 1.5 parts of triethylamine and 5 parts of antibacterial nanosheets, continue to react for 1.2 h, then add 90 parts of deionized water and 2.5 parts of dimethyl silicone oil, stir at 400 r / min for 2.5 h, collect the product after natural defoaming to obtain the polyurethane coating.

[0058] Performance testing

[0059] The polyurethane coatings prepared in Examples 1-3 and Comparative Example 3 were applied to steel plates meeting specifications and cured at 100°C for 1 hour to prepare samples meeting specifications. The abrasion resistance of the samples was tested according to standard GB / T1768-2006 to determine their abrasion performance. The antibacterial rate of the samples was tested according to standard GB / T21866-2008 to determine their antibacterial ability. The water contact angle of the samples was tested using a JC2000D2G water contact angle tester to determine their antifouling ability. Specific test results are shown in the table below:

[0060]

[0061] As shown in the table above, the samples prepared in Examples 1-3 all exhibit excellent wear resistance, antibacterial properties, and stain resistance, meeting the usage requirements in various environments. The sample prepared in Comparative Example 1 did not contain anti-fouling gellan gum, so its stain resistance was poor. The sample prepared in Comparative Example 2 did not contain antibacterial nanosheets, so it had almost no antibacterial effect. The sample prepared in Comparative Example 3 directly incorporated vinyl gellan gum and antibacterial nanosheets, resulting in excellent antibacterial effect and good wear resistance, but its stain resistance was not as good as that of the examples, which would increase the difficulty of cleaning in actual use.

[0062] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0063] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, and all such modifications and additions should be protected by the present invention.

Claims

1. A stain-resistant polyurethane coating, characterized in that, Including the following parts by weight of raw materials: 20-25 parts isophorone diisocyanate, 15-20 parts polytetrahydrofuran ether diol, 0.3-0.5 parts organotin catalyst, 5-8 parts anti-fouling guar gum, 3-5 parts 1,4-butanediol, 1-2 parts triethylamine, 4-6 parts antibacterial nanosheets, 80-100 parts deionized water, 2-3 parts defoamer; The method for preparing the antifouling gel includes the following steps: S1: Place guar gum in acetone, mix and stir thoroughly, introduce nitrogen gas, add dimethylvinylchlorosilane, heat and reflux to react, collect the product to obtain ethylene-modified guar gum. S2: Place the ethylene-based gellan gum in anhydrous ethanol, add perfluorohexyl ethyl acrylate and an initiator, heat to 55-65℃, react for 6-8 hours, collect the product after vacuum distillation, and obtain antifouling gellan gum. The method for preparing the antibacterial nanosheets includes the following steps: SS1: Papyrrolidone and 4-dimethylaminobenzoyl chloride were placed in chloroform, a catalyst was added, and the mixture was stirred thoroughly for 6-8 hours. After filtration and separation, the mixture was washed, vacuum dried, soaked in deionized water for 20-30 minutes, and vacuum dried again. The product was then collected to obtain modified palyrrolidone. SS2: Modified palygorskite and 2,3-epoxypropyltrimethylammonium chloride were placed in anhydrous ethanol, ultrasonically dispersed for 10-15 min, heated to react, filtered, washed, and the product was collected to obtain antibacterial nanosheets.

2. The antifouling polyurethane coating according to claim 1, characterized in that, The organotin catalyst is either dibutyltin dilaurate or stannous octoate; the neutralizing agent is triethylamine; and the defoamer is dimethyl silicone oil.

3. The antifouling polyurethane coating according to claim 1, characterized in that, In step S1, the heating and reflux reaction time is 12-18 hours.

4. The antifouling polyurethane coating according to claim 1, characterized in that, In step S2, the initiator is either azobisisobutyronitrile or azobisisoheptanenitrile.

5. The antifouling polyurethane coating according to claim 1, characterized in that, In step SS1, the catalyst is pyridine.

6. The antifouling polyurethane coating according to claim 1, characterized in that, In step SS2, the temperature of the heating reaction is 65-75℃, and the time is 6-8h.

7. A method for producing the antifouling polyurethane coating as described in claim 1, characterized in that, The preparation steps include the following: Step 1: Mix isophorone diisocyanate and polytetrahydrofuran ether diol evenly, introduce nitrogen gas, add organotin catalyst, heat to 50-55℃ and react for 1-1.5h, continue to heat to 75-85℃ and react for 1-1.5h to obtain polyurethane prepolymer; Step 2: Add anti-fouling gellan gum and 1,4-butanediol to the polyurethane prepolymer, heat to 80-85℃ and react for 5-6 hours, then cool to 45-55℃ and add neutralizing agent and antibacterial nanosheets. Continue to react for 1-1.5 hours, then add deionized water and defoamer, stir thoroughly for 2-3 hours, and collect the product after natural defoaming to obtain polyurethane coating.

8. The method for producing an antifouling polyurethane coating according to claim 7, characterized in that, In step two, the stirring rate for thorough mixing is 300-500 r / min.

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