CN113698816A - Antibacterial coating and preparation method and application thereof - Google Patents

Abstract

The invention discloses an antibacterial coating and a preparation method and application thereof, and relates to the technical field of antibacterial coatings. The antibacterial coating comprises the following components: chitosan, tannic acid, zinc nanoparticles, copper nanoparticles, a tackifier and an organic solvent; the mass ratio of the chitosan to the tannic acid is 50-95: 5-50; the total mass fraction of the zinc nanoparticles and the copper nanoparticles is 1-5% based on the total mass of the chitosan and the tannic acid; the mass fraction of the tackifier is 0.5-3%; the mass fraction of the organic solvent is 10-30%. The antibacterial coating has good antibacterial performance, and meanwhile, the coating has high stability and can resist bacteria for a long time.

Description

Antibacterial coating and preparation method and application thereof

Technical Field

The invention relates to the technical field of antibacterial coatings, in particular to an antibacterial coating and a preparation method and application thereof.

Background

With the large-scale application of plastic products, the antibacterial performance requirements of consumers on the plastic products are higher and higher, and the application of antibacterial materials is gradually a new trend for household products. The design of an effective method for constructing the surface coating with the antibacterial function has important practical significance.

The antibacterial coating is a coating material which is endowed with the function of inhibiting the growth of surface thalli or directly killing germs on the premise of not changing the performance of the material body by modifying the surface of the material. The antibacterial coatings can be classified into four categories according to the difference of action mechanisms: contact antibacterial coating, anti-adhesion antibacterial coating and intelligent antibacterial coating. The contact type antibacterial coating is the first type of antibacterial coating researched, and is characterized in that organic molecules or inorganic antibacterial materials with antibacterial functions are directly fixed on the surface of a material, and after bacteria and fungi contact the material, the surface antibacterial molecules kill the germs contacting the material by adopting a chemical mechanism or a physical mechanism.

The organic antibacterial agent has the advantages of strong initial sterilization capability, good sterilization immediate effect and broad-spectrum antibacterial property, mature technology and relatively low price; the disadvantages are poor chemical stability, poor heat resistance, easy volatilization and difficult realization of long-acting sterilization. The natural antibacterial agent chitosan in the organic antibacterial agent is the only alkaline polysaccharide in nature, and compared with a synthetic polymer material, the natural antibacterial agent chitosan has the characteristics of wide source, low price, stable property, no stimulation, no sensitization, no mutation and the like, and has good film forming property and antibacterial property. At present, chitosan is mainly used in a coating material in a molecular chain form, and due to the fact that the mutual force among chitosan molecular chains is strong, the resistance among the molecular chains in the coating preparation process is large, the formed coating is prone to being uneven.

Tannic acid is a water-soluble dendritic polyphenol, and has natural antibacterial property. The molecules of the adhesive contain a large number of phenolic hydroxyl groups, and the adhesive can interact with the surface of a matrix and increase the adhesiveness between the adhesive and the matrix. However, the tannin molecule contains more rigid benzene ring structures, so that the film forming property is not ideal when the tannin is used alone, and the application of the tannin in coating is limited.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an antibacterial coating which has good antibacterial property, good stability and convenient use, and a preparation method and application thereof.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: an antimicrobial coating comprising the following ingredients: chitosan, tannic acid, zinc nanoparticles, copper nanoparticles, a tackifier and an organic solvent; the mass ratio of the chitosan to the tannic acid is 50-95: 5-50; the total mass fraction of the zinc nanoparticles and the copper nanoparticles is 1-5% based on the total mass of the chitosan and the tannic acid; the mass fraction of the tackifier is 0.5-3%; the mass fraction of the organic solvent is 10-30%.

The chitosan is positively charged in the solution and is combined with bacteria with negative charges on the surface through electrostatic interaction to change the permeability on the cell membrane of the bacteria, so that a great amount of intracellular nutrients are leaked out to damage the cell membrane, thereby killing the bacteria. The tannic acid has stronger adsorption capacity due to more catechol structures, and has stronger adsorption capacity compared with other polyphenol ligands containing catechol. The zinc nanoparticles have extremely strong penetrating power on cell membranes of microorganisms, can directly penetrate cell nuclei to interfere DNA, so that the microorganisms rarely generate drug resistance, and have the characteristics of long-acting antibiosis, no toxicity and no residue; the copper nanoparticles can generate chemical reaction under the aerobic condition with certain humidity to generate hydroxyl radicals and active oxygen ions, and the hydroxyl radicals and the active oxygen ions have strong oxidizing capability and can destroy the cell proliferation capability of microorganisms, so that the microorganisms are inhibited and killed. The organic antibacterial agent chitosan, the tannic acid, the inorganic antibacterial agent zinc nanoparticles and the copper nanoparticles are compounded, so that the antibacterial capacity and the antibacterial durability of the antibacterial coating can be greatly improved.

Preferably, the mass ratio of the zinc nanoparticles to the copper nanoparticles is 1:0.25-4, and when the mass ratio of the two inorganic antibacterial materials meets the above limit, the antibacterial rate of the prepared antibacterial coating on staphylococcus aureus and escherichia coli can reach more than 80%.

Further preferably, the mass ratio of the zinc nanoparticles to the copper nanoparticles is 1:0.65-1.5, and when the mass ratio of the zinc nanoparticles to the copper nanoparticles meets the above limit, the antibacterial rate of the antibacterial coating on staphylococcus aureus and escherichia coli can reach more than 85%.

Preferably, the chitosan comprises at least one of β -1, 4-poly-glucosamine, carboxymethyl chitosan.

The structure of the chitosan has great influence on the performance of the antibacterial coating, and when the antibacterial coating is prepared by the two kinds of chitosan, the antibacterial property and the antibacterial durability are better.

Preferably, the particle size D90 of the zinc nanoparticles is less than 100 nm; the average particle diameter of the copper nano-particles is 70-90nm, and the specific surface area is 12-18g/m²。

The size of the particles has great influence on the dispersibility and the chemical reaction activity, and when the particle size is small and the specific surface area is large, the chemical reaction is more likely to occur, and the antibacterial effect is better; however, the specific surface area is too large, particles are easy to agglomerate, and finally, the dispersibility of the coating is influenced, the combination of the coating and a substrate is influenced, and the coating is peeled off.

Preferably, the viscosity increasing agent is sodium cellulose sulfate. The sodium cellulose sulfate can increase the binding force between the coating and the substrate, so that the coating can have long-acting antibiosis.

Preferably, the solvent comprises at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, benzyl alcohol, toluene, phthalate, ethyl acetate, dimethyl sulfoxide, tetrahydrofuran, acetone, cyclohexanone, butanone, n-heptane, cyclohexane, dichloromethane, trichloromethane.

Meanwhile, the invention also discloses a preparation method of the antibacterial coating, which comprises the following steps:

(1) mixing chitosan, tannic acid, zinc nanoparticles and copper nanoparticles, and putting the mixture into a high-speed mixer for dry mixing treatment to obtain a mixture; the mixing technological parameters are as follows: the rotating speed is 800-;

(2) adding the tackifier and the solvent into a stirrer, stirring for 20-30min at the rotating speed of 600-;

(3) and coating the antibacterial coating on the surface of the substrate, and drying to obtain the antibacterial coating.

The dry mixing condition and the stirring condition have great influence on the particle fineness and the dispersibility of the coating and the network structure of organic molecules, the coating is uneven when the rotating speed is too low and the processing time is too short, and the binding force between a subsequent coating and a substrate is influenced to a certain extent, but the rotating speed is too high and the network structure of the organic molecules is damaged when the processing time is too long. When the antibacterial coating is prepared by the process, the binding force between the coating and the substrate is high, and the antibacterial coating has good antibacterial performance.

In addition, the invention also discloses application of the antibacterial coating in the field of plastic household products. The base material of the household product is polypropylene, polyethylene, acrylonitrile-butadiene-styrene copolymer, polyester resin, polystyrene plastic and the like.

Compared with the prior art, the invention has the beneficial effects that: the chitosan can effectively prevent the zinc nanoparticles and the copper nanoparticles from agglomerating, the positive charges on the surface of the chitosan and the zinc nanoparticles or the copper nanoparticles are enhanced after the chitosan is combined with the zinc nanoparticles or the copper nanoparticles, and the chitosan is more easily complexed with the anionic components on the cell surface, so that the aim of sterilization is fulfilled. In addition, the chitosan, the zinc and copper metal nanoparticles and the tannic acid can generate a synergistic antibacterial effect after being compounded, and the microorganisms are difficult to generate tolerance to the chitosan. Meanwhile, the proportion of the two metal nano particles, the type of the tackifier and the use amount of each component are selected, so that the prepared coating has good adhesive force with the substrate, and the coating has long-term antibacterial efficiency.

Detailed Description

To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples.

The following examples and comparative examples used the following starting materials:

beta-1, 4-poly-glucosamine (Shanghai Huyu Biotech Co., Ltd., product number 0060);

carboxymethyl chitosan (Shanghai Yuan Ye Biotech Co., Ltd., product No. S30948, white powder carboxylation degree is more than or equal to 80%);

hydroxypropyl chitosan (Nantong LvSend bioengineering Co., Ltd., product number HPCS, pH 5-7, degree of substitution not less than 80%);

the tannic acid is hydrolyzable tannic acid (Henan Delitai chemical product Co., Ltd., product number DNS101, glucose content of about 12%, melting point 218 deg.C, density 2.129g/cm³)；

Zinc nanoparticles (Huizhou Huansheng new material Co., Ltd., product number HKJ103-1, particle size D90 < 100nm, pH 6-8);

copper nanoparticles (produced by Fulangshi (Beijing) nanotechnology, product number FCU080, spherical crystal, specific surface area 15g/m²Average particle size 80 nm);

sodium cellulose sulfate (Henan Ji beauty products Co., Ltd., product No. CMC FVH9, its molecule contains anionic substituent, all monosaccharides are composed of C₁、C₄The bond between the two bonds is glycoside bond, the molecular weight Mn is 122180, the Mw/Mn is about 1.112, the Mooney viscosity is 71-89ML_1-4100 ℃; adhesion of 173-;

para-tert-butylphenol resin (New Zealand shor, Foshan City, product No. N-2391, weight average molecular weight Mw of about 250, Mooney viscosity of 52-64ML_1-4100 ℃; the adhesion is 88-128g/14 mm);

the substrate is a PP sheet (product number NP-01, Liaoning Panjin Haixing Co., Ltd.).

Example 1

In an embodiment of the present invention, the antibacterial coating is prepared from the following components in parts by weight: 95 parts of beta-1, 4-poly-glucosamine, 5 parts of tannic acid, 0.5 part of zinc nanoparticles, 0.5 part of copper nanoparticles, 0.5 part of sodium cellulose sulfate and 10 parts of ethanol; the preparation method comprises the following steps:

(1) weighing beta-1, 4-poly-glucosamine, tannic acid, copper nanoparticles and zinc nanoparticles according to the mass ratio, putting the raw material components into a high-speed mixer for dry mixing treatment, wherein the mixing technological parameters are as follows: the rotating speed is 800r/min, and the time is 4 min;

(2) weighing cellulose sodium sulfate and n-heptane according to a mass ratio, adding into a stirrer, stirring at a rotating speed of 600r/min for 20min, adding the uniformly mixed material in the step (1), and continuously stirring at a rotating speed of 400r/min for 50min to obtain an antibacterial coating;

(3) and coating the antibacterial material on the surface of a matrix, and drying to obtain the antibacterial coating.

Example 2

In an embodiment of the present invention, the antibacterial coating is prepared from the following components in parts by weight: 85 parts of carboxymethyl chitosan, 15 parts of tannic acid, 1 part of zinc nanoparticles, 1 part of copper nanoparticles, 1.5 parts of cellulose sodium sulfate and 15 parts of n-butyl alcohol; the preparation method comprises the following steps:

(1) weighing carboxymethyl chitosan, tannic acid, copper nanoparticles and zinc nanoparticles according to a mass ratio, and putting the raw material components into a high-speed mixer for dry mixing treatment, wherein the mixing technological parameters are as follows: the rotating speed is 850r/min, and the time is 5 min;

(2) weighing cellulose sodium sulfate and n-heptane according to the mass ratio, adding into a stirrer, stirring at the rotating speed of 650r/min for 22min, then adding the uniformly mixed material in the step (1), and continuously stirring at the rotating speed of 450r/min for 52min to obtain the antibacterial coating;

(3) and coating the antibacterial material on the surface of a matrix, and drying to obtain the antibacterial coating.

Example 3

In an embodiment of the present invention, the antibacterial coating is prepared from the following components in parts by weight: 75 parts of beta-1, 4-poly-glucosamine, 25 parts of tannic acid, 1.5 parts of zinc nanoparticles, 1.5 parts of copper nanoparticles, 2 parts of cellulose sodium sulfate and 20 parts of phthalate; the preparation method comprises the following steps:

(1) weighing beta-1, 4-poly-glucosamine, tannic acid, copper nanoparticles and zinc nanoparticles according to the mass ratio, putting the raw material components into a high-speed mixer for dry mixing treatment, wherein the mixing technological parameters are as follows: the rotating speed is 900r/min, and the time is 6 min;

(2) weighing cellulose sodium sulfate and n-heptane according to a mass ratio, adding into a stirrer, stirring at a rotating speed of 700r/min for 24min, adding the uniformly mixed material in the step (1), and continuously stirring at a rotating speed of 500r/min for 54min to obtain an antibacterial coating;

(3) and coating the antibacterial material on the surface of a matrix, and drying to obtain the antibacterial coating.

Example 4

In an embodiment of the present invention, the antibacterial coating is prepared from the following components in parts by weight: 50 parts of carboxymethyl chitosan, 50 parts of tannic acid, 2 parts of zinc nanoparticles, 2 parts of copper nanoparticles, 2.5 parts of cellulose sodium sulfate and 25 parts of n-heptane; the preparation method comprises the following steps:

(1) weighing carboxymethyl chitosan, tannic acid, copper nanoparticles and zinc nanoparticles according to a mass ratio, and putting the raw material components into a high-speed mixer for dry mixing treatment, wherein the mixing technological parameters are as follows: the rotating speed is 950r/min, and the time is 6 min;

(2) weighing cellulose sodium sulfate and n-heptane according to a mass ratio, adding into a stirrer, stirring at a rotating speed of 750r/min for 27min, then adding the uniformly mixed material in the step (1), and continuously stirring at a rotating speed of 550r/min for 57min to obtain an antibacterial coating;

(3) and coating the antibacterial material on the surface of a matrix, and drying to obtain the antibacterial coating.

Example 5

In an embodiment of the present invention, the antibacterial coating is prepared from the following components in parts by weight: 62 parts of beta-1, 4-poly-glucosamine, 38 parts of tannic acid, 2.5 parts of zinc nanoparticles, 2.5 parts of copper nanoparticles, 3 parts of cellulose sodium sulfate and 30 parts of n-heptane; the preparation method comprises the following steps:

(1) weighing carboxymethyl chitosan, tannic acid, copper nanoparticles and zinc nanoparticles according to a mass ratio, and putting the raw material components into a high-speed mixer for dry mixing treatment, wherein the mixing technological parameters are as follows: the rotating speed is 1000r/min, and the time is 7 min;

(2) weighing cellulose sodium sulfate and n-heptane according to a mass ratio, adding into a stirrer, stirring at a rotating speed of 800r/min for 30min, adding the uniformly mixed material in the step (1), and continuously stirring at a rotating speed of 600r/min for 60min to obtain an antibacterial coating;

(3) and coating the antibacterial material on the surface of a matrix, and drying to obtain the antibacterial coating.

Examples 6 to 9

In the embodiment of the antibacterial coating, the preparation methods of the embodiments 6 to 9 are the same as those of the embodiment 3, and the difference between the formula of the antibacterial coating and the embodiment 3 is only that the proportion of the zinc nanoparticles and the copper nanoparticles is different, and the specific proportion is shown in table 1.

Comparative examples 1 to 2

Comparative examples 1 to 2 are antibacterial coatings, which are prepared in the same manner as in example 3, and whose formulations are different from example 3 only in that copper nanoparticles and zinc nanoparticles are not included, respectively, but the total amount of metal nanoparticles is the same as in example 3.

TABLE 1

Item

Comparative example 1

Example 6

Example 7

Example 8

Example 9

Comparative example 2

Zn：Cu

1:0

1:0.25

1:0.65

1:1.5

1:4

0:1

Example 10

In an embodiment of the present invention, the preparation method of the antibacterial coating in this embodiment is the same as that in embodiment 3, and the difference between the formulation of the antibacterial coating and embodiment 3 is only that the chitosan used is hydroxypropyl chitosan.

Example 11

An embodiment of the present invention provides an antibacterial coating, which is prepared in the same manner as in example 3, and the difference between the formulation of the antibacterial coating and example 3 is that the tackifier used is p-tert-butyl phenolic resin.

The examples 1-11 have moderate viscosity and are convenient to use and can be uniformly coated on a substrate.

Comparative example 3

An antimicrobial coating which differs from example 3 only in that no adhesion promoter is added.

Comparative example 4

An antibacterial coating prepared according to the same method as that of example 3 and having the following formulation: 10 parts of beta-1, 4-poly-glucosamine, 90 parts of tannic acid, 1.5 parts of zinc nanoparticles, 1.5 parts of copper nanoparticles, 2 parts of cellulose sodium sulfate and 20 parts of phthalate.

Comparative example 5

An antibacterial coating prepared according to the same method as that of example 3 and having the following formulation: 30 parts of beta-1, 4-poly-glucosamine, 70 parts of tannic acid, 1.5 parts of zinc nanoparticles, 1.5 parts of copper nanoparticles, 2 parts of cellulose sodium sulfate and 20 parts of phthalate.

Comparative example 6

An antibacterial coating layer was prepared in the same manner as in example 3, and its formulation was different from example 3 only in that it did not contain zinc nanoparticles and copper nanoparticles.

The performance tests of examples 1 to 11 and comparative examples 1 to 6 were performed, and the antibacterial properties of the antibacterial coating layer on the day after the preparation and after 1 month of immersion in water were respectively tested with reference to ASTM E2149-01, and the test results are shown in table 2.

TABLE 2

As can be seen from Table 2, the antibacterial properties of examples 1 to 11 are significantly superior to those of comparative examples 1 to 6. Compared with the embodiment 3, the antibacterial property of the copper-containing nano particles or the zinc nano particles in the comparative examples 1-2 is greatly reduced, which shows that the two metal nano particles can interact with each other to improve the antibacterial property of the antibacterial coating; comparative example 3 because no tackifier is added, the stability of the coating is poor, the antibacterial property is obviously reduced after the coating is soaked in water for one month, and the coating is seriously peeled off; the dosage of the chitosan in the comparative examples 4-5 is less than that of the tannic acid, so that the antibacterial property is obviously reduced, and the chitosan and the tannic acid can act synergistically when the ratio of the chitosan to the tannic acid is 50-95:5-50, so that the antibacterial property of the coating is improved; the comparative example 6 does not contain metal nanoparticles, and the antibacterial property is sharply reduced, which shows that the metal nanoparticles can act with the organic antibacterial agent to improve the antibacterial property of the antibacterial coating.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims (9)

1. An antimicrobial coating, comprising the following components: chitosan, tannic acid, zinc nanoparticles, copper nanoparticles, a tackifier and an organic solvent; the mass ratio of the chitosan to the tannic acid is 50-95: 5-50; the total mass fraction of the zinc nanoparticles and the copper nanoparticles is 1-5% based on the total mass of the chitosan and the tannic acid; the mass fraction of the tackifier is 0.5-3%; the mass fraction of the organic solvent is 10-30%.

2. The antimicrobial coating of claim 1, wherein the mass ratio of zinc nanoparticles to copper nanoparticles is 1: 0.25-4.

3. The antimicrobial coating of claim 2, wherein the mass ratio of zinc nanoparticles to copper nanoparticles is from 1:0.65 to 1.5.

4. The antimicrobial coating of claim 1, wherein the chitosan comprises at least one of β -1, 4-poly-glucosamine, carboxymethyl chitosan.

5. The antimicrobial coating of claim 1, wherein the zinc nanoparticles have a particle size D90 < 100 nm; the average particle diameter of the copper nano-particles is 70-90nm, and the specific surface area is 12-18g/m²。

6. The antimicrobial coating of claim 1, wherein the adhesion promoter is sodium cellulose sulfate.

7. The antimicrobial coating of claim 1, wherein the solvent comprises at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, benzyl alcohol, toluene, phthalate, ethyl acetate, dimethyl sulfoxide, tetrahydrofuran, acetone, cyclohexanone, butanone, n-heptane, cyclohexane, dichloromethane, and chloroform.

8. A method of preparing an antimicrobial coating according to any one of claims 1 to 7, comprising the steps of:

(1) mixing chitosan, tannic acid, zinc nanoparticles and copper nanoparticles, and putting the mixture into a high-speed mixer for dry mixing treatment to obtain a mixture; the mixing technological parameters are as follows: the rotating speed is 800-;

(2) adding the tackifier and the solvent into a stirrer, stirring for 20-30min at the rotating speed of 600-;

(3) and coating the antibacterial coating on the surface of the substrate, and drying to obtain the antibacterial coating.

9. Use of an antimicrobial coating according to any one of claims 1 to 7 in the field of plastic household articles.