Zinc thiazole-containing coating and antibacterial application of zinc thiazole coating

Abstract

The invention relates to a zinc thiazole-containing coating and antibacterial application thereof, the zinc thiazole-containing coating contains zinc thiazole particles, the total weight of the zinc thiazole particles accounts for 0.01-5% of the weight of the coating, and the particle size D90 of the zinc thiazole particles is 100-2000 nm. The application problem of the zinc thiazole coating is solved by regulating and controlling the concentration, the particle size and the density of the zinc thiazole particles in the coating.

Description

Technical Field

[0001] This invention belongs to the field of industrial antibacterial agents, specifically relating to a coating containing zinc thiazole and the antibacterial use of zinc thiazole coating. Background Technology

[0002] Thiazole zinc (chemical name: 2-amino-5-mercapto-1,3,4-thiadiazole zinc), molecular formula: C4H4N6S4Zn, relative molecular mass is 329.8, the technical product is a grayish-white powder with a melting point greater than 300℃, insoluble in water and organic solvents, and stable under neutral and weakly alkaline conditions.

[0003] Thiazole zinc can be used in agricultural production, mainly for the control of bacterial diseases. It can control soft rot, black spot, anthracnose, rust, powdery mildew, and zinc deficiency senescence in cabbage; bacterial wilt, root rot, and leaf spot in peanuts; stunted growth, yellowing, and rotting seedlings, bacterial stripe, bacterial leaf blight, sheath blight, rice blast, and zinc deficiency fire in rice; and bacterial angular leaf spot, canker, downy mildew, target disease, yellow spot, and zinc deficiency chlorosis in cucumbers. It can also inactivate viruses, such as bacterial canker, late blight, brown spot, anthracnose, and zinc deficiency little leaf disease in tomatoes. The main application method is to spray with a 500-800 times dilution at the initial stage of disease. Increase (decrease) the dilution ratio for severe disease. It is advisable to apply 2-3 times consecutively at approximately 7-day intervals. Note the importance of secondary dilution during spraying.

[0004] At the time, there was little research on whether it could achieve antibacterial effects in coatings. Its similar substance, 2-mercaptobenzothiazole zinc, has some disclosed applications in coatings, mainly as an antibacterial and accelerator, but these do not suggest that thiazole zinc can still solve the problem in coatings. For example, the role of 2-mercaptobenzothiazole zinc varies in different coatings. In most cases, it is used as an accelerator, as shown in the technical solutions disclosed in Chinese patent applications CN200910170590.1 and CN201580031924.0, where 2-mercaptobenzothiazole zinc is used as a vulcanization accelerator, not as an antibacterial agent. The dosage and usage requirements for 2-mercaptobenzothiazole zinc do not provide any insight into how thiazole zinc can achieve antibacterial effects in coatings.

[0005] Sometimes, zinc bis(triazole) is also used as a catalyst. For example, CN201110170989.7 discloses a matting agent for epoxy-polyester powder coatings. This matting agent is prepared by blending a catalyst with a carboxylated acrylic resin or an epoxy-based acrylic resin. The key design element is that 2-mercaptobenzothiazole zinc salt is used as a catalyst, and the carboxylated acrylic resin or epoxy-based acrylic resin is used as the reactant to prepare the matting agent. This patent achieves good matting stability and mechanical properties, solving the technical problems of poor mechanical properties and easy yellowing of traditional chemical matting agents. Sometimes, thiazolium zinc is used as an antibacterial agent in coatings, but its effect is insufficient. On the one hand, it needs to be used in combination with other antibacterial agents, and on the other hand, there is no clear product characteristic of thiazolium zinc to achieve antibacterial properties. For example, the antifouling coating disclosed in CN201210196760.5 includes, by weight percentage, 1-50% antimicrobial composition, 0.1-50% copper and / or inorganic copper compounds, 10-85% siloxane-acrylic resin and 1-70% rosin metal salt and / or rosin derivative metal salt. The antimicrobial composition contains nitrile antimicrobial agents, pyridyl antimicrobial agents, haloalkylthio-based antimicrobial agents, organic iodine-based antimicrobial agents, thiazolyl antimicrobial agents and benzimidazole-based antimicrobial agents, and the siloxane-acrylic resin contains 3-15% by mass of siloxane. As thiazol-based antimicrobial agents, isothiazolin-3-one compounds and benzothiazole compounds are preferred. Examples of benzothiazole compounds include 2-(4-thiocyanomethylthio)benzothiazole, 2-mercaptobenzothiazole sodium, and 2-mercaptobenzothiazole zinc.

[0006] Furthermore, Chinese patent application CN03817489.8 discloses a sheet-like antimicrobial article comprising a porous sheet-like matrix impregnated with a water-based antimicrobial composition for use in industrial and commercial applications. The water-based antimicrobial composition comprises: a) at least one polymer emulsion or dispersion; and b) at least one antimicrobial component that is substantially non-leaching and substantially free of environmentally harmful substances. Examples of usable antimicrobial components disclosed therein include, for example, zinc olman, sodium olman, sodium borate, zinc borate, barium metaborate, calcium borate, iodoalkynyl alkyl carbamate, diiodomethyl-p-tolyl sulfone, 2,4-thiazolyl-benzimidazole, 2-n-octyl-4-isothiazolin-3-one, zinc dimethyl dithiocarbamate, 2-mercaptobenzothiazole zinc, potassium N-hydroxymethyl-N-methyl dithiocarbamate, 2- The ingredients include sodium mercaptobenzothiazole, 5-hydroxymethoxymethyl-1-aza-3,7-dioxa-bicyclooctane, 2,3,5,6-tetrachloro-4-pyridine, zinc 2-pyridinethiol-1-oxide, N-trichloromethylthiobenzoic acid imide, tetrachloro-m-phenylenediamine, deltamethrin, fipronil, permethrin, flufenoxuron, imidacloprid, and mixtures thereof. However, the patent does not disclose whether zinc thiazole can be used in this coating or how zinc thiazole can exert its antibacterial properties.

[0007] This invention provides a coating containing zinc thiazole, which achieves excellent antibacterial properties without affecting the coating's performance. Summary of the Invention

[0008] To solve the above-mentioned technical problems, the present invention provides a coating containing zinc thiazole, wherein the coating contains zinc thiazole particles, the total weight of the zinc thiazole particles accounting for 0.01%-5% of the weight of the coating, and the particle size D of the zinc thiazole particles is... 90 The range is 100nm-2000nm.

[0009] The primary purpose of using zinc thiazole in coatings is to achieve antibacterial effects against bacteria and fungi in daily life. The concentration of zinc thiazole used varies in different coatings, but generally, the required mass percentage is greater than 100 ppm. In some coatings, such as those used in environments with complex or even excessively high densities of harmful bacteria, the content of zinc thiazole particles can be increased to 5%, which means the mass content of zinc thiazole particles reaches 50,000 ppm.

[0010] The particle size requirements for thiazolium zinc vary depending on the coating. Some coatings have lower flowability requirements, so the particle size requirements for thiazolium zinc particles are generally lower. Larger thiazolium zinc particles can be directly mixed with the coating, or the particles can be directly applied to the coating surface. Generally, the particle size D...90 A particle size of 800-200 nm is sufficient, but some coatings require higher flowability and a larger particle density to achieve better antibacterial properties. Thiazole zinc particles with a particle size D... 90 The general requirement is that it be less than or equal to 1 micrometer.

[0011] Therefore, preferably, in the above coating, the particle size D of the thiazole zinc particles is... 90 The preferred particle size for thiazole zinc particles is 100-2000 nm. 90 Thiazole zinc particles with a particle size D less than or equal to 1000 nm, and particularly preferred, have a particle size D. 90 The range is 300-1000nm.

[0012] Preferably, in the above-mentioned coating, the bulk density of the thiazole zinc particles in the coating is 1.9 × 10⁻⁶. 2 -1.19×10 13 10c particles / cm3. Preferably, the bulk density of the thiazole zinc particles in the coating is 2.4 × 103. 4 -1.19×10 13 The bulk density of thiazole zinc particles in the coating is particularly preferred to be 8.8 × 10⁻⁶ particles per cubic centimeter. 5 -1.19×10 16 8.8 × 10³ cubic centimeters or 8.8 × 10⁻⁶ cubic centimeters 5 -1.19×10 10 The preferred bulk density of thiazolium zinc particles in the coating is 8.8 × 10⁻⁶ particles per cubic centimeter. 5 -4.42×10 11 Units per cubic centimeter.

[0013] Given a fixed concentration and particle size range, the density distribution of thiazolium zinc particles will exhibit a more pronounced antibacterial effect under the aforementioned conditions, without affecting the quality of the original industrial materials.

[0014] Preferably, the coating further contains other bactericides, and the weight ratio of the other bactericides to the weight of thiazolium zinc is 1:(0.01-100).

[0015] Generally, other bactericides should be selected if they are poorly soluble in water or organic solvents. This is because if other antibacterial agents are too soluble in organic solvents and aqueous solutions, the antibacterial effect will be lost. At the same time, the presence of pores will affect the antibacterial properties of thiazole zinc.

[0016] "Poorly soluble in organic solvents" means that the solubility of a bactericide in a conventional organic solvent at room temperature is less than 5 g / 100 ml, and "poorly soluble in water" means that the solubility of a bactericide in water at room temperature is less than 5 g / 100 ml.

[0017] Preferably, in the above-mentioned coating, the coating is a prepared but uncoated coating slurry, or a coated and dried coating.

[0018] In the above-mentioned coatings, the coatings are interior wall coatings, exterior wall coatings, wood coatings, or metal coatings. Preferably, the coatings are interior wall coatings or exterior wall coatings. More preferably, the coatings are water-based coatings.

[0019] Preferably, the coating further comprises a film-forming substance, additives, solvents, and water.

[0020] The film-forming substance is preferably a cellulose derivative, natural resin, synthetic resin, or synthetic emulsion; the auxiliary agent is preferably an antifoaming agent or a leveling agent; the solvent is preferably a hydrocarbon solvent, including but not limited to ethers, ketones, and esters.

[0021] Preferably, the coating further comprises pigments and fillers, wherein the pigments are preferably titanium dioxide, etc., and the fillers are calcium carbonate, talc, etc.

[0022] The present invention also provides the use of thiamethoxam zinc particles to enhance the antibacterial properties of coatings, wherein the thiamethoxam zinc particles constitute 0.01%-5% by weight in the coating, and the particle size D of the thiamethoxam zinc particles is... 90 The range is 100nm-2000nm.

[0023] Preferably, in the above-mentioned applications, the bulk density of the thiazole zinc particles in the coating is 1.9 × 10⁻⁶. 2 -1.19×10 13 10 particles / cm³. Particularly preferred is a bulk density of thiazole zinc particles in the coating of 8.8 × 10⁻⁶. 5 -4.42×10 11 Units per cubic centimeter.

[0024] The present invention also provides a method for preparing coatings using zinc thiazole particles, characterized in that the zinc thiazole particles are prepared into a suspension, and then the suspension is added to other components of the coating and thoroughly stirred and mixed to obtain a coating containing zinc thiazole particles.

[0025] Beneficial effects of the present invention

[0026] 1. Thiazole zinc, as an agricultural fungicide, has always been used in biodegradable environments, and its residue must meet certain requirements during use. Therefore, how to control its concentration and other technical indicators in coating products has always been a challenge. This invention solves this problem by breaking through the bottleneck of thiazolium zinc coating application by controlling the concentration, particle size, and particle density requirements of thiazolium zinc.

[0027] 2. The application of thiazolium zinc in coatings, especially in semi-finished paste or slurry coatings and finished solid coatings, is critical in terms of the application environment. In particular, the density requirements of thiazolium zinc particles inside and on the surface of the coating are very important. This requires that thiazolium zinc particles be dispersed in the coating at a certain density. This invention not only solves the problem of the content of thiazolium zinc in coatings, but also solves the density requirements of thiazolium zinc particles in coatings. Detailed Implementation

[0028] The thiazole zinc used in the following examples is produced specifically to obtain thiazole zinc granules as needed. The specific production method is as follows:

[0029] A zinc sulfate solution with a molar concentration of 4 mol / L was heated to 70°C, then pressurized and added to a sodium thiazolyl solution using a hydraulic lance. The initial speed of the hydraulic lance was adjusted. The sodium thiazolyl solution had a molar concentration of 8 mol / L and a temperature of 75°C. The sodium thiazolyl solution was stirred using a combination of mechanical and pneumatic stirring, with the stirring speed adjusted as needed. After the zinc thiazolyl solution was added, the stirring speed and temperature were maintained, and the reaction was continued for 1 hour while the reaction apparatus was subjected to ultrasonic vibration. After the reaction was completed, the temperature was lowered at a rate of 20°C / hour, while maintaining the stirring speed. The zinc thiazolyl particles prepared by the above method were centrifuged, precipitated, washed, centrifuged again, washed, and dried. The particle size of the zinc thiazolyl particles was then measured. Zinc thiazolyl particles of different sizes were prepared using the above method and then formulated into suspensions for later use.

[0030] The conditions for the above method can also be found in Chinese patent application CN201711478553.8, "A method for preparing micro-sized thiazole zinc", which describes the preparation methods for thiazole zinc with different particle sizes.

[0031] All materials used in the following examples were purchased from the market.

[0032] Example 1: Study on the antibacterial properties of coatings containing thiazole zinc

[0033] To verify the preparation effect of thiazolium zinc in interior wall coatings, the particle size and concentration of thiazolium zinc were adjusted. First, the particle size of thiazolium zinc particles was kept constant to verify the antibacterial effect of different contents of thiazolium zinc in the coating. Then, the antibacterial effect of thiazolium zinc particles with different particle sizes was studied by fixing the weight percentage of thiazolium zinc particles.

[0034] Application of particle size D 90The preparation method for interior wall coatings using zinc thiazole (1.53 μm) is as follows: Weigh 250 g of deionized water into a 2-liter container, then add 1 g of hydroxymethyl cellulose while stirring. After stirring evenly, add 400 g of ethylene-vinyl acetate emulsion, then add 250 g of titanium dioxide and 100 g of talc powder. Finally, add zinc thiazole suspension (zinc thiazole content 30% wt, particle size D). 90 =1.53), the content of thiazolium zinc in the coating was adjusted by adding the amount of thiazolium zinc suspension. Thorough stirring was performed to achieve the required coating specifications. Then, the antibacterial properties of the coatings with different amounts of thiazolium zinc were measured.

[0035] The specific results are as follows:

[0036]

[0037] Based on the percentage of thiazolium zinc in the suspension concentrate, the weight percentage of thiazolium zinc in the coating was calculated. It was found that when the particle size was 1.53 μm and the weight percentage of thiazolium zinc was 0.59-2.09%, the antibacterial performance against Escherichia coli and Staphylococcus aureus reached 100%. When the weight percentage of thiazolium zinc was greater than 0.5 wt%, the coating would not dilute after application in normal air until it dried, meaning that it could prevent the coating from becoming contaminated during the drying process.

[0038] Example 2: Study on the antibacterial properties of thiazole zinc coatings with different particle sizes

[0039] The formulation of the above-mentioned coating products was modified, fixing the content of thiazolium zinc at 0.05% wt, which is equivalent to adding 1.67 g of 30% thiazolium zinc suspending agent to the coating. The particle size of the thiazolium zinc particles was varied, and the dry and wet antibacterial properties of coatings containing thiazolium zinc of different particle sizes were studied. Specific results are as follows:

[0040]

[0041] It was found that when the particle size D of thiamethoxam zinc was... 90 At a nanometer range of 360-1760 nm, it can ensure that the coating will not be infected by Escherichia coli and Staphylococcus aureus during storage (coating slurry) and application (coating slurry). At a nanometer range of 360-2850 nm, the coating can achieve 100% antibacterial performance against Escherichia coli and Staphylococcus aureus after drying.

[0042] When the particle size D of thiamethoxam zinc particles 90For wavelengths smaller than 1000 nm and larger than 300 nm, the coating slurry and the dried coating layer are exposed to multiple microorganisms, especially in environments with organic pollution and high humidity. The antibacterial properties of the coating still meet the required antibacterial standards. For example, regarding the antibacterial effect against mold, with a concentration of 0.05% wt for thiazole zinc at 810 nm, 520 nm, and 360 nm, the coating achieves 100% antibacterial effect against mold. Similarly, the antibacterial effect against yeast and algae also reaches 100%.

[0043] Using the above method, antibacterial experiments were conducted on coatings with thiazolium zinc of different particle sizes. The bulk density of the thiazolium zinc particles in the coatings was then measured. Different amounts of thiazolium zinc of different particle sizes were added to different coatings, and their antibacterial properties were tested. The coatings with better antibacterial performance had a bulk density of thiazolium zinc particles of around 8.8 × 10⁻⁶. 5 -4.42×10 11 Within the range of particles per cubic centimeter, if the particle size of thiamethoxam zinc is relatively large, its percentage content may meet the requirements, but its antibacterial performance may not meet the requirements. For example, if the particle size D is large... 90 Thiazole zinc with a particle size of 35 μm needs to reach a content of 16% to meet the antibacterial requirements of the coating. This means that the bulk density of the thiazolium zinc particles at this concentration is approximately 8.5-9.1 × 10⁻⁶. 5 The bulk density, through measurements of other coatings that meet the antibacterial requirements, all showed that as the particle bulk density reached 8.8 × 10⁻⁶, the bulk density increased. 5 After reaching a particle density of 4.42 × 10³ cm³, the higher the density of the thiamethoxam zinc granules, the higher the antibacterial performance. 11 When the concentration of zinc thiazole is 10 particles per cubic centimeter, it can achieve excellent antibacterial properties in paint slurry. However, for dried paint, it can lead to other problems and affect the performance of the paint, especially for large-particle zinc thiazole particles, such as particle D. 90 Problems arise when the size exceeds 3 micrometers.

[0044] Waterborne polyurethane coatings and waterborne epoxy coatings were prepared using the above-mentioned thiazole zinc suspensions with different particle sizes, and their antibacterial effects were tested. The antibacterial effects were basically the same as those in Examples 1 and 2, proving that the thiazole zinc particles in different coatings all satisfy the relationship between their particle size, particle number, mass concentration and antibacterial effect.

Claims

1. A coating comprising zinc thiazole, said coating comprising zinc thiazole particles, wherein the total weight of the zinc thiazole particles accounts for 0.01%-5% of the weight of the coating, and the particle size D of the zinc thiazole particles is... 90 The range is 100nm-2000nm.

2. The coating according to claim 1, wherein the particle size D of the thiazole zinc particles is... 90 The preferred particle size D of thiamethoxam zinc particles is 100-2000 nm. 90 Thiazole zinc particles with a particle size D less than or equal to 1000 nm, and particularly preferred, have a particle size D. 90 The range is 300-1000nm.

3. The coating according to claim 1, characterized in that... The bulk density of thiazole zinc particles in the coating is 1.9 × 10⁻⁶. 2 -1.19×10 13 Preferably, the bulk density of thiazole zinc particles in the coating is 2.4 × 10⁻⁶ particles / cubic centimeter. 4 -1.19×10 13 The bulk density of thiazole zinc particles in the coating is particularly preferred to be 8.8 × 10⁻⁶ particles per cubic centimeter. 5 -1.19×10 16 8.8 × 10³ cubic centimeters or 8.8 × 10⁻⁶ cubic centimeters 5 -1.19×10 10 The preferred bulk density of thiazolium zinc particles in the coating is 8.8 × 10⁻⁶ particles per cubic centimeter. 5 -4.42×10 11 Units per cubic centimeter.

4. The coating according to claim 1, characterized in that... The coating also contains other bactericides, and the weight ratio of the other bactericides to the weight of thiazole zinc is 1:(0.01-100).

5. The coating according to claim 1, characterized in that... The coating is either a prepared but uncoated coating slurry, or a coated and dried coating layer.

6. The coating according to claim 5, characterized in that... The coating is an interior wall coating, an exterior wall coating, a wood coating, or a metal coating. Preferably, the coating is an interior wall coating or an exterior wall coating. More preferably, the coating is a water-based coating.

7. The coating according to any one of claims 1-6, characterized in that... The coating also contains film-forming substances, additives, solvents, and water.

8. The coating according to claim 7, characterized in that... The coating also contains pigments and fillers.

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