Bacteriostatic agent for paints

Abstract

The present invention relates to the technical field of paint additives and, in particular, to a bacteriostatic agent for use in paints. The bacteriostatic agent for use in paints contains, by weight: 1 to 3 parts 2-(4-thiazolyl)benzimidazole, 1 to 2 parts 1,2-benzisothiazolin-3-one, 1 to 2 parts chitosan, 0.5 to 1 part sodium alginate, 0.1 to 0.4 parts nano-calcium carbonate, 0.1 to 0.4 parts ferrous sulfate, 0.1 to 0.4 parts SiO2, 1 to 2 parts emulsifier, and 50 parts water. The bacteriostatic agent provided in the present invention can effectively inhibit various molds, has good application performance, and is easy to smooth.

Description

TECHNICAL AREA

[0001] The present invention relates to the technical field of paint additives and in particular to a bacteriostatic agent for use in coatings. BACKGROUND

[0002] In recent years, China's economic development has significantly improved people's living conditions, and the boom in the housing sector has created a huge market for the growth of the building paints and decorative materials industry. Water-soluble chemical products such as paints (latex paints), resin emulsions, adhesives, and metalworking fluids contain substances like thickeners, defoamers, surfactants, starches, and proteins. Many of these substances are nutrients for the growth of microorganisms and contain some water. At the right ambient temperature, microorganisms can grow and multiply in large numbers, causing the product to coagulate, harden, lose its viscosity and adhesion, change its acidity, and, in the worst case, even discolor, smell, and flake, rendering the products unusable.By adding suitable preservatives during production, the growth and multiplication of microorganisms can be effectively prevented, and the products are protected from spoilage.

[0003] Based on the relevant requirements of the World Health Organization (WHO), the United Nations, the Food and Agriculture Organization of the United Nations, the Union for International Cancer Control, and international environmental protection committees, antifungal agents must meet the following conditions: (1) a broad spectrum of activity and high efficacy against bacteria; (2) minimal toxicity to the human body and strict control over indicators such as acute toxicity, subacute toxicity, teratogenicity, and carcinogenicity; (3) low toxicity to poultry, livestock, and fish, and no cumulative toxicity; (4) good stability, colorless, insensitive, non-irritating, and compatible with materials; (5) minimal environmental pollution; and (6) wide availability and low price.The mechanisms of action of antifungal drugs include: destruction of cell structures, impairment of mitosis, inhibition of chromosome division, impairment of spore germination and growth, prevention of metabolism, inhibition of enzyme synthesis, and so on.

[0004] Therefore, the provision of a bacteriostatic agent for use in coatings with high efficacy, low toxicity and low environmental impact is of great importance for indoor safety.

[0005] Against this background, the present invention is proposed. SUMMARY

[0006] The present invention relates to a bacteriostatic agent for use in coatings, which contains in parts by weight: 1 to 3 parts 2-(4-Thiazolyl)benzimidazole, 1 to 2 parts 1,2-Benzisothiazolin-3-one, 1 to 2 parts chitosan, 0.5 to 1 part sodium alginate, 0.1 to 0.4 parts nano-calcium carbonate, 0.1 to 0.4 parts ferrous sulfate, 0.1 to 0.4 parts SiO2, 1 to 2 parts emulsifier and 50 parts water.

[0007] As compound bacteriostatic ingredients, 2-(4-thiazolyl)benzimidazole, 1,2-benzisothiazolin-3-one, chitosan, ferrous sulfate, and SiO2 exhibit excellent inhibitory activity against various molds. Chitosan can combine with sodium alginate and certain calcium ions in nano-calcium carbonate to form a network structure, thereby achieving adsorption and long-lasting effects. Furthermore, sodium alginate and nano-calcium carbonate can also increase the viscosity and adhesion of the bacteriostatic agent, allowing it to more easily form a uniform coating on a substrate surface.

[0008] Optionally, the bacteriostatic agent for use in coatings contains, in parts by weight: 1.5 to 2.5 parts 2-(4-Thiazolyl)benzimidazole, 1.3 to 1.7 parts 1,2-Benzisothiazolin-3-one, 1.3 to 1.7 parts chitosan, 0.6 to 0.9 parts sodium alginate, 0.2 to 0.3 parts nano-calcium carbonate, 0.2 to 0.3 parts ferrous sulfate, 0.2 to 0.3 parts SiO2, 1 to 2 parts emulsifier and 50 parts water.

[0009] In the aforementioned bacteriostatic agent for use in coatings, the particle size of SiO2 can range from 1 nm to 50 µm.

[0010] The emulsifier sodium dodecylbenzenesulfonate may be present in the aforementioned bacteriostatic agent for use in coatings.

[0011] The present invention further provides a water-soluble paint containing the above bacteriostatic agent for use in coatings.

[0012] Alternatively, the percentage of the added bacteriostatic agent in the aforementioned water-soluble paint for use as a coating agent is 1% by weight to 10% by weight.

[0013] According to a further aspect of the present invention, the present invention also relates to a method for producing the above-mentioned bacteriostatic agent for use in coatings, including: (1) Addition of 2-(4-thiazolyl)benzimidazole, 1,2-benzisothiazolin-3-one, chitosan, iron(II) sulfate and SiO2 to water and stirring of the resulting mixture until thoroughly mixed; and (2) Add sodium alginate, nano-calcium carbonate and emulsifier while stirring the resulting mixture slowly until a viscous liquid is formed.

[0014] Step (1) can be carried out by high-speed stirring, e.g. stirring at 1000 to 3000 rpm for 5 to 10 minutes.

[0015] The present invention also relates to methods for applying paints, and the bacteriostatic agent for use in coatings can be applied in two methods: In one embodiment, the water-soluble paint is applied to a substrate surface, and the aforementioned bacteriostatic agent for use in coatings is applied before the water-soluble paint dries.

[0016] In another embodiment, the aforementioned water-soluble paint is applied to the substrate surface (i.e., premixing first and then applying it together).

[0017] The substrate according to the present invention can consist of metal, glass, plastic, a wall, wood, etc.

[0018] In some cases, the application is done by brushing or rolling.

[0019] The advantageous effects of the present invention are as follows: The bacteriostatic agent provided in the present invention can effectively inhibit various mold fungi, has good application performance, and is easy to smooth. DETAILED DESCRIPTION

[0020] Detailed reference is made to embodiments of the present invention, and one or more examples are described below. Each example serves to illustrate, not to limit, the present invention. Indeed, a person skilled in the art can make various modifications and changes to the present invention without departing from its scope or spirit. For example, features shown or described as part of one embodiment can be used in another embodiment to create yet another embodiment.

[0021] Unless otherwise specified, all terms (including technical and scientific terms) used in the disclosure of the present invention have the same meaning as they would be generally understood by a person with ordinary knowledge in the field to which the present invention belongs. For better understanding of instructions relating to the present invention, the following definitions are used. The terms used herein in the description of the present invention serve only to describe certain embodiments and are not intended to limit the present invention.

[0022] The terms “comprise”, “include” and “contain” used in the present invention are synonymous and do not exclude additional, unmentioned members, elements or process steps.

[0023] A range of values ​​in the present invention, defined by endpoints, includes all values, fractions and the said endpoints that fall within the range.

[0024] A concentration value, which is the subject of the present invention, can fluctuate within a certain range. For example, the concentration value can fluctuate within a corresponding precision range. A precision range of 2%, for instance, allows fluctuations of ±0.1%. For a larger value, or a value that does not require fine control, a larger fluctuation is also permissible. For example, a precision range of 100 mM can allow fluctuations of ±1%, ±2%, ±5%, etc. For the molecular weight, a fluctuation of ±10% is permissible.

[0025] Within the scope of the present invention, terms such as "several" and "different" refer to two or more than two, unless otherwise specified.

[0026] Within the scope of the present invention, the technical features in the open-ended descriptions include both closed technical solutions consisting of the listed features and open technical solutions containing the listed features.

[0027] In the present invention, “preferred”, “better”, “advantageous” and “suitable” are intended only to describe embodiments or examples with better effect and should not be understood as limiting the scope of protection of the present invention.

[0028] The embodiments of the present invention are described in detail below with reference to examples. It should be understood that these examples are used only to illustrate the present invention, and it is not intended to limit its scope. In the following examples, for a test method for which a specific condition is not specified, reference is preferably made to the instructions in the present invention, a test manual, a conventional prior art condition, another prior art test method, or a manufacturer's condition.

[0029] In the following specific examples, a measurement parameter relating to an ingredient may exhibit a slight deviation within a weighing accuracy range, unless otherwise specified. For temperature and time parameters, an acceptable deviation is permitted due to the instrument's testing accuracy or operational accuracy. Example 1: Preparation of a bacteriostatic agent for use in paints

[0030] (1) 2 kg 2-(4-Thiazolyl)benzimidazole, 1.5 kg 1,2-benzisothiazolin-3-one, 1.5 kg chitosan, 0.25 kg iron(II) sulfate and 0.25 kg SiO2 were added to 50 l of water, and the resulting mixture was stirred for 8 minutes at 2000 rpm until thoroughly mixed.

[0031] (2) 0.7 kg sodium alginate, 0.25 kg nano-calcium carbonate and emulsifier were added while the resulting mixture was stirred slowly until a viscous liquid was formed. Example 2: Preparation of a bacteriostatic agent for use in paints

[0032] (1) 1 kg 2-(4-Thiazolyl)benzimidazole, 2 kg 1,2-benzisothiazolin-3-one, 1 kg chitosan, 0.4 kg iron(II) sulfate and 0.1 kg SiO2 were added to 50 l of water, and the resulting mixture was stirred at 3000 rpm for 5 minutes until thoroughly mixed.

[0033] (2) 1 kg sodium alginate, 0.4 kg nano-calcium carbonate and emulsifier were added while the resulting mixture was stirred slowly until a viscous liquid was formed. Example 3: Preparation of a bacteriostatic agent for use in paints

[0034] (1) 3 kg 2-(4-Thiazolyl)benzimidazole, 1 kg 1,2-benzisothiazolin-3-one, 2 kg chitosan, 0.1 kg iron(II) sulfate and 0.4 kg SiO2 were added to 50 l of water, and the resulting mixture was stirred at 1000 rpm for 10 minutes until thoroughly mixed.

[0035] (2) 0.5 kg sodium alginate, 0.1 kg nano-calcium carbonate and emulsifier were added while the resulting mixture was stirred slowly until a viscous liquid was formed. Example 4 Order processing 1. A room was ventilated without damaging any original wall surface. 2. Surface objects on a wall with mold or crystalline efflorescence were wiped with a damp duster. 3. A layer of water-soluble paint was applied; and when 70% to 80% of the water-soluble paint had dried, the bacteriostatic agent for use as a paint in the present invention was brushed or rolled along the wall from the outside inwards, the time interval depending on the degree of dryness of the wall being about 2 to 3 hours, and the bacteriostatic agent for use as a paint could not be sprayed or brushed from the inside out in order to prevent an overflow phenomenon and the proliferation of mold fungi to the outside. 4. After applying the bacteriostatic agent, paper was glued on or the paint was reapplied as needed. 5. The bacteriostatic agent should be applied at intervals of 2 to 3 hours and brushed or rolled on 2 to 3 times, provided that the bacteriostatic agent has dried in the air each time (i.e., the bacteriostatic agent does not stick to the hands). 6. If the wall was damaged, the bacteriostatic agent should be applied after it has dried. If cracks were present, they were filled with plaster and fungicide or with plaster and bacteriostatic agent. After drying, any sticky surface or paint was smoothed to prepare for further construction. Test example: mold resistance test

[0036] The method developed a test to simulate the growth conditions of molds in nature, based on the physiological properties of molds during growth, in order to determine the inhibitory effect of the bacteriostatic agent on molds under these conditions. The method specifies a visual inspection method for determining mold growth in order to evaluate the performance of the mold resistance agent. Test strains

[0037] Aspergillus niger (Aspergillus niger), Aspergillus flavus (Aspergillus flavus), Chaetorium globosum (Chaetorium globosum), Paecilomyces varioti (Paecilomyces varioti), and Penicillium citrinum (Penicillium citrinum). Testing procedure

[0038] With reference to GB / T 1741-79(89) Test Methods for Determining the Resistance of Paints Film to Mold, the following test steps were carried out: (1) Preparation of a spore suspension: The aforementioned molds were separately inoculated onto inclined surfaces of potato dextrose medium (PDA) and cultivated at 28°C to 30°C for 7 to 14 days to produce a large number of spores. Small amounts of sterile saline solution were withdrawn and separately dripped onto inclined surfaces, then mycelium and spores were gently scraped off with a sterile inoculation needle. The resulting mixture was thoroughly and evenly agitated and filtered through two layers of gauze. 50 ml of a sterile solution containing 1% to 2% Tween 80 was added, and the number of mold spores present in the mixed bacterial solution at this time was approximately 10 cfu / ml. The spore suspension was used on the same day or after storage for a maximum of 3 days at 3°C ​​to 7°C. (2) Preparation of the test sample: The bacteriostatic agent was applied to a 2.5 cm × 5.0 cm (or 5.0 cm × 5.0 cm) rectangular aluminum sheet, and 3 duplicate samples were prepared for each sample and air-dried for later use. (3) Preparation of a plate culture medium: A nutrient salt medium was injected into a sterile Petri dish until a thickness of 3 to 6 mm was reached, and then cured for later use (within 48 hours). (4) Inoculation of the sample: The prepared sample was placed flat on the surface of the inorganic salt medium, the suspension was sprayed evenly and finely onto the sample using an atomizer, and after slight drying, the Petri dish was covered with a Petri dish lid. The lid was labeled with the sample name, a serial number, and a date. Three parallel samples were prepared for each sample. (5) Cultivation: A negative control sample was spread onto the plate medium (with filter paper or cotton gauze), and the spore suspension was sprayed completely and evenly onto the medium and filter paper using a sprayer containing freshly prepared spore suspension. The aforementioned Petri dish was placed in a storage bag, the storage bag was tightly sealed, and the dish was placed in an incubator for cultivation. The temperature was 28°C and the humidity was 90%. The samples were cultured for 14 to 28 days under the above conditions, aerated once every 7 days, and observed and recorded (the negative control sample was checked on day 7, and obvious bacteria should be growing on filter paper or cotton gauze in the control sample; otherwise, the spore suspension should be reconstituted). Results-determining criteria

[0039] After 28 days of cultivation, the results were evaluated as follows: Level 0 - no mold; Stage 1 - Mold spots had a diameter of about 1 mm and were sparsely distributed; Stage 2 - Mold spots had a diameter of approximately 2 mm or were located within a range of 2 mm and should not be distributed over a maximum of one quarter of the total surface; Stage 3 - Mold spots had a diameter of approximately 2 mm or should not be spread over half of the total surface; and Stage 4 - the majority of the mold spots had a diameter of more than 5 mm or the mycelium was spread over the entire surface.

[0040] Excessive bacterial growth in the sample could lead to the test being terminated prematurely.

[0041] The bacteriostatic effect of the bacteriostatic agent according to the invention was as follows: Negative control sample Bacteriostatic agent according to the present invention Aspergillus niger 4 0 Aspergillus flavus 4 0 Chaetorium globosum 4 0 Paecilomyces varioti 4 1 Penicillium citrinum 4 0

[0042] The foregoing results show that the bacteriostatic agent provided in the present invention has excellent mold-resistant properties, and a comprehensive assessment of the mold safety level was level 0.

[0043] The preceding embodiments describe only a few examples of the present invention. The descriptions are relatively detailed and specific, but cannot be interpreted as limiting the scope of the present invention. It should be noted that a person skilled in the art could also make several variations and improvements without departing from the concept of the present invention. These variations and improvements all fall within the scope of protection of the present invention.

Claims

[1] Bacteriostatic agent for use in coatings, containing by weight: 1 to 3 parts 2-(4-thiazolyl)benzimidazole, 1 to 2 parts 1,2-benzisothiazolin-3-one, 1 to 2 parts chitosan, 0.5 to 1 part sodium alginate, 0.1 to 0.4 parts nano-calcium carbonate, 0.1 to 0.4 parts ferrous sulfate, 0.1 to 0.4 parts SiO2, 1 to 2 parts emulsifier and 50 parts water. [2] Bacteriostatic agent for use in coatings according to claim 1, containing in parts by weight: 1.5 to 2.5 parts 2-(4-Thiazolyl)benzimidazole, 1.3 to 1.7 parts 1,2-Benzisothiazolin-3-one, 1.3 to 1.7 parts chitosan, 0.6 to 0.9 parts sodium alginate, 0.2 to 0.3 parts nano-calcium carbonate, 0.2 to 0.3 parts ferrous sulfate, 0.2 to 0.3 parts SiO2, 1 to 2 parts emulsifier and 50 parts water. [3] Bacteriostatic agent for use in coatings according to claim 1 or 2, wherein the particle size of SiO2 is 1 nm to 50 µm. [4] Bacteriostatic agent for use in coatings according to claim 1 or 2, wherein the emulsifier is sodium dodecylbenzenesulfonate. [5] Water-soluble paint containing the bacteriostatic agent for use in coatings according to any one of claims 1 to 4. [6] Water-soluble paint according to claim 5, wherein the percentage of the added bacteriostatic agent for use in coatings is 1 wt.% to 10 wt.% [7] Method for producing the bacteriostatic agent for use in coatings according to any one of claims 1 to 4, comprising: (1) Addition of 2-(4-thiazolyl)benzimidazole, 1,2-benzisothiazolin-3-one, chitosan, iron(II) sulfate and SiO2 to water and stirring of the resulting mixture until thoroughly mixed; and (2) Addition of sodium alginate, nano-calcium carbonate and emulsifier, stirring the resulting mixture slowly until a viscous liquid is formed. [8] Method for applying paint, comprising: applying a water-soluble paint to a substrate surface and applying the bacteriostatic agent for use in coatings according to any one of claims 1 to 4, before the water-soluble paint dries. [9] Method for applying paint, comprising: applying the water-soluble paint according to claim 5 or 6 to a substrate surface.