Anticorrosive and antibacterial coating, preparation method and application thereof and household appliance

Abstract

The invention discloses an anticorrosive and antibacterial coating, a preparation method and application thereof and a household appliance, and belongs to the technical field of household appliance shell coatings. Comprising a preparation step of quaternized polyethyleneimine functionalized graphene oxide and a preparation step of quaternized polyethyleneimine functionalized graphene oxide reinforced epoxy resin. The preparation method of the quaternized polyethyleneimine functionalized graphene oxide reinforced epoxy resin comprises the following steps: carrying out a covalent reaction between an amino group of quaternized polyethyleneimine functionalized graphene oxide and epoxy resin to obtain the quaternized polyethyleneimine functionalized graphene oxide reinforced epoxy resin. The coating is applied to the aspect of household appliance shell coatings, solves the problems that existing household appliance coatings are poor in corrosion resistance and cannot meet antibacterial requirements, and has long-term corrosion resistance and efficient antibacterial performance.

Description

Technical Field

[0001] The invention belongs to the technical field of household appliance shell coatings, and in particular relates to an anticorrosive and antibacterial coating, a preparation method and application thereof, and household appliances. Background Art

[0002] The metal shell of household appliances usually has a layer of paint on it to protect it from corrosion. Epoxy resin coatings are widely used as an economical and effective anti-corrosion strategy. However, the holes caused by solvent evaporation greatly reduce its anti-corrosion ability, which seriously affects the anti-corrosion performance of epoxy resin coatings. Graphene oxide has a high specific surface area and good physical shielding effect, making it the preferred high-performance filler. It can be used as a filler to enhance the anti-corrosion performance of epoxy resin, but it also has the problem of poor compatibility with epoxy resin.

[0003] In addition, with the improvement of the quality of life, people's awareness of health and hygiene safety has gradually increased, and they are more concerned about the bacterial content in the living environment. As a product that users can touch, the health of household appliances is also increasingly concerned. Therefore, it is of great significance to develop an anticorrosive and antibacterial coating with long-term anticorrosion and high-efficiency antibacterial properties. Summary of the invention

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to overcome the problem that the existing home appliance coatings have poor anti-corrosion performance and cannot meet the antibacterial requirements, and propose an anti-corrosion and antibacterial coating with long-term anti-corrosion and high-efficiency antibacterial performance, its preparation method, application and home appliances.

[0005] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0006] On one hand, the present invention provides a method for preparing an anticorrosive and antibacterial coating, comprising the steps of preparing quaternized polyethyleneimine functionalized graphene oxide and preparing epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide; the step of preparing epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide comprises: utilizing a covalent reaction between amino groups of quaternized polyethyleneimine functionalized graphene oxide and epoxy resin to obtain epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide.

[0007] Preferably, the preparation steps of the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin specifically include: adding the quaternized polyethyleneimine functionalized graphene oxide to the dissolved epoxy resin, stirring to obtain a uniform dispersion, rotary evaporating the uniform dispersion, adding a diluent, stirring, and then adding a polyamide curing agent and a defoaming agent to obtain the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin.

[0008] Preferably, the preparation step of the quaternized polyethyleneimine functionalized graphene oxide comprises: adding graphene oxide, quaternized polyethyleneimine and N,N'-dicyclohexylcarbodiimide to N,N-dimethylformamide, ultrasonically treating the mixture in an ice bath to completely dissolve the mixture to obtain a mixed solution, heating the mixed solution in a water bath to allow the mixture to react sufficiently, washing the mixed solution and drying the mixed solution to obtain the quaternized polyethyleneimine functionalized graphene oxide.

[0009] Preferably, the epoxy resin is selected from any one of E-31, E-35, E-42, E-44, E-51, and E-55.

[0010] Preferably, the diluent in the step of preparing the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin is a mixed solution of xylene and n-butanol.

[0011] Preferably, the defoaming agent in the preparation step of the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin is a silicone defoaming agent.

[0012] Preferably, the average sheet diameter of the graphene oxide in the step of preparing quaternized polyethyleneimine functionalized graphene oxide is any value in the range of 0.5-5 μm.

[0013] The present invention also provides an anticorrosive and antibacterial coating, which is prepared by the preparation method of the anticorrosive and antibacterial coating described in any of the above technical solutions. The anticorrosive and antibacterial coating is an epoxy resin reinforced with quaternized polyethyleneimine functionalized graphene oxide, and a covalent reaction occurs between the amino group of the quaternized polyethyleneimine functionalized graphene oxide in the epoxy resin reinforced with quaternized polyethyleneimine functionalized graphene oxide and the epoxy resin.

[0014] Another aspect of the present invention provides the use of the anticorrosive and antibacterial coating in a coating for a housing of a household appliance, wherein the anticorrosive and antibacterial coating forms a coating with a thickness of 100±10 μm on the surface of the housing of the household appliance.

[0015] The present invention also provides a household appliance, wherein the surface of the housing of the household appliance is covered with a coating formed by the anticorrosive and antibacterial coating.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The invention provides a method for preparing an anticorrosive and antibacterial coating. First, quaternary ammonium polyethyleneimine functionalized graphene oxide is prepared. Then, by means of a covalent reaction between amino groups of the quaternary ammonium polyethyleneimine functionalized graphene oxide and epoxy resin, good compatibility of the graphene oxide in the epoxy resin is achieved. Meanwhile, a large number of cations on the surface of the quaternary ammonium polyethyleneimine can destroy the cell membrane structure of bacteria, hinder ion exchange and material exchange between the bacteria and the outside world, and further cause the death of the bacteria. The prepared coating exhibits excellent anticorrosive and antibacterial properties under the synergistic effect of the physical shielding effect of the graphene oxide and the bactericidal property of the quaternary ammonium polyethyleneimine. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram showing the antibacterial effect of the blank control group in Example 1 of the present invention;

[0019] Figure 2 This is a diagram showing the antibacterial effect of the anticorrosive and antibacterial coating in Example 1 of the present invention. DETAILED DESCRIPTION

[0020] The technical scheme in the specific embodiment of the present invention is described in detail and completely below. Obviously, the described embodiment is only a part of the specific implementation of the overall technical scheme of the present invention, rather than all implementations. Based on the overall concept of the present invention, all other embodiments obtained by ordinary technicians in this field fall within the scope of protection of the present invention.

[0021] On one hand, the present invention provides a method for preparing an anticorrosive and antibacterial coating, comprising the steps of preparing quaternized polyethyleneimine functionalized graphene oxide and preparing epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide; the step of preparing epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide comprises: utilizing a covalent reaction between amino groups of quaternized polyethyleneimine functionalized graphene oxide and epoxy resin to obtain epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide. The preparation method first prepares quaternary ammonium polyethyleneimine functionalized graphene oxide, and then, by means of a covalent reaction between the amino groups of the quaternary ammonium polyethyleneimine functionalized graphene oxide and the epoxy resin, achieves good compatibility of the graphene oxide in the epoxy resin. At the same time, a large number of cations on the surface of the quaternary ammonium polyethyleneimine can destroy the cell membrane structure of bacteria, hinder ion exchange and material exchange between the bacteria and the outside world, and then cause the death of the bacteria. Under the synergistic effect of the physical shielding effect of graphene oxide and the bactericidal property of the quaternary ammonium polyethyleneimine, the prepared coating exhibits excellent anticorrosion and antibacterial properties.

[0022] In a preferred embodiment, the preparation step of the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin specifically includes: adding the quaternized polyethyleneimine functionalized graphene oxide to the dissolved epoxy resin, stirring to obtain a uniform dispersion, rotary evaporating the uniform dispersion, adding a diluent, stirring, adding a polyamide curing agent and a defoaming agent to obtain the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin. Optionally, in the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin, the mass fraction of the quaternized polyethyleneimine functionalized graphene oxide is 1-3wt.%, preferably 2wt.%. Regarding the preparation method, it further includes: completely dissolving 10g of epoxy resin with 50mL of ethanol, adding 0.1-0.3g of quaternized polyethyleneimine functionalized graphene oxide, magnetically stirring for 30min to obtain a uniform dispersion of quaternized polyethyleneimine functionalized graphene oxide in the epoxy resin, then rotary evaporating in a rotary evaporator for 45min to completely volatilize the ethanol, adding 2.5g of diluent, stirring for 30min to reduce the viscosity of the epoxy resin, then adding 5g of polyamide curing agent and 0.2mL of defoaming agent to the above solution, continuing to stir for 30min, and after the coating is evenly mixed, a quaternized polyethyleneimine functionalized graphene oxide reinforced epoxy resin with a mass fraction of 1wt.% is obtained.

[0023] In a preferred embodiment, the preparation step of the quaternized polyethyleneimine functionalized graphene oxide includes: adding graphene oxide, quaternized polyethyleneimine and N,N'-dicyclohexylcarbodiimide to N,N-dimethylformamide, ultrasonically treating the mixture in an ice bath to completely dissolve the mixture to obtain a mixed solution, heating the mixed solution in a water bath to fully react, washing and drying the mixture to obtain the quaternized polyethyleneimine functionalized graphene oxide. It further includes: adding 400mg of graphene oxide, 200mg of quaternized polyethyleneimine and 100mg of N,N'-dicyclohexylcarbodiimide to 150mL of N,N-dimethylformamide, ultrasonically treating the mixture in an ice bath for 40min to completely dissolve the mixture, heating the mixture in a water bath at 60°C, reacting for 24h, washing the obtained solution several times with anhydrous ethanol and deionized water, and finally freeze-drying the mixture to obtain the quaternized polyethyleneimine functionalized graphene oxide.

[0024] In a preferred embodiment, the epoxy resin is selected from any one of E-31, E-35, E-42, E-44, E-51, and E-55. This embodiment specifically defines the type of epoxy resin, and it is understood that the type of epoxy resin can also be other substances reasonably selected by those skilled in the art in the art in combination with common knowledge.

[0025] In a preferred embodiment, the diluent in the step of preparing the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin is a mixed solution of xylene and n-butanol.

[0026] In a preferred embodiment, the defoamer in the preparation step of the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin is an organosilicon defoamer, wherein the organosilicon defoamer includes silicone oil defoamer, diatomaceous earth defoamer, silicate defoamer, polysiloxane defoamer, etc.

[0027] In a preferred embodiment, the average sheet diameter of the graphene oxide in the preparation step of the quaternized polyethyleneimine functionalized graphene oxide is any value in the range of 0.5-5 μm. This embodiment specifically defines the average sheet diameter of the graphene oxide because the graphene oxide in this size range has a high aspect ratio, can provide a good shielding effect, and ensures excellent corrosion resistance. It is understood that the average sheet diameter of the graphene oxide can also be 1 μm, 2 μm, 3 μm, 4 μm, and any point value within the range.

[0028] The present invention also provides an anticorrosive and antibacterial coating, which is prepared by the preparation method of the anticorrosive and antibacterial coating described in any of the above technical solutions, wherein the anticorrosive and antibacterial coating is an epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide, and a covalent reaction occurs between the amino groups of the quaternized polyethyleneimine functionalized graphene oxide and the epoxy resin in the epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide. The anticorrosive and antibacterial coating is an epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide, and the long-term anticorrosive and high-efficiency antibacterial properties of the coating are achieved by functionalizing the graphene oxide.

[0029] Another aspect of the present invention provides the use of the anticorrosive and antibacterial coating in a coating for a housing of a household appliance, wherein the anticorrosive and antibacterial coating forms a coating with a thickness of 100±10 μm on the surface of the housing of the household appliance.

[0030] The present invention also provides a household appliance, wherein the surface of the housing of the household appliance is covered with a coating formed by the anticorrosive and antibacterial coating. The household appliance has the characteristics of anticorrosive and antibacterial.

[0031] In order to more clearly and in detail introduce the anticorrosive and antibacterial coating, its preparation method, application and household appliances provided by the embodiments of the present invention, a description will be given below in conjunction with specific embodiments.

[0032] Example 1

[0033] A method for preparing a quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin comprises the following steps:

[0034] (1) Preparation of quaternary polyethyleneimine functionalized graphene oxide: 400 mg of graphene oxide, 200 mg of quaternary polyethyleneimine and 100 mg of N,N'-dicyclohexylcarbodiimide were added to 150 mL of N,N-dimethylformamide and ultrasonicated for 40 min in an ice bath to completely dissolve the graphene oxide. The mixed solution was heated in a water bath at 60°C and reacted for 24 h. The resulting solution was washed several times with anhydrous ethanol and deionized water and finally freeze-dried to prepare quaternary polyethyleneimine functionalized graphene oxide.

[0035] (2) Preparation of coating: 10 g of epoxy resin was completely dissolved in 50 mL of ethanol, 0.1 g of quaternized polyethyleneimine functionalized graphene oxide was added, and magnetic stirring was performed for 30 min to obtain a uniform dispersion of quaternized polyethyleneimine functionalized graphene oxide in epoxy resin. Then, the ethanol was completely evaporated by rotary evaporation in a rotary evaporator for 45 min. 2.5 g of diluent was added dropwise and stirred for 30 min to reduce the viscosity of the epoxy resin. Then, 5 g of polyamide curing agent and 0.2 mL of defoamer were added to the above solution, and stirring was continued for 30 min. After the coating was evenly mixed, a quaternized polyethyleneimine functionalized graphene oxide reinforced epoxy resin with a mass fraction of 1 wt.% was obtained.

[0036] Example 2

[0037] A method for preparing a quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin comprises the following steps:

[0038] (1) Preparation of quaternary polyethyleneimine functionalized graphene oxide: 400 mg of graphene oxide, 200 mg of quaternary polyethyleneimine and 100 mg of N,N'-dicyclohexylcarbodiimide were added to 150 mL of N,N-dimethylformamide and ultrasonicated for 40 min in an ice bath to completely dissolve the graphene oxide. The mixed solution was heated in a water bath at 60°C and reacted for 24 h. The resulting solution was washed several times with anhydrous ethanol and deionized water and finally freeze-dried to prepare quaternary polyethyleneimine functionalized graphene oxide.

[0039] (2) Preparation of coating: 10 g of epoxy resin was completely dissolved in 50 mL of ethanol, 0.2 g of quaternized polyethyleneimine functionalized graphene oxide was added, and magnetic stirring was performed for 30 min to obtain a uniform dispersion of quaternized polyethyleneimine functionalized graphene oxide in epoxy resin. Then, the ethanol was completely evaporated by rotary evaporation in a rotary evaporator for 45 min. 2.5 g of diluent was added dropwise and stirred for 30 min to reduce the viscosity of the epoxy resin. Then, 5 g of polyamide curing agent and 0.2 mL of defoamer were added to the above solution, and stirring was continued for 30 min. After the coating was evenly mixed, a quaternized polyethyleneimine functionalized graphene oxide reinforced epoxy resin with a mass fraction of 2 wt.% was obtained.

[0040] Example 3

[0041] A method for preparing a quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin comprises the following steps:

[0042] (1) Preparation of quaternary polyethyleneimine functionalized graphene oxide: 400 mg of graphene oxide, 200 mg of quaternary polyethyleneimine and 100 mg of N,N'-dicyclohexylcarbodiimide were added to 150 mL of N,N-dimethylformamide and ultrasonicated for 40 min in an ice bath to completely dissolve the graphene oxide. The mixed solution was heated in a water bath at 60°C and reacted for 24 h. The resulting solution was washed several times with anhydrous ethanol and deionized water and finally freeze-dried to prepare quaternary polyethyleneimine functionalized graphene oxide.

[0043] (2) Preparation of coating: 10 g of epoxy resin was completely dissolved in 50 mL of ethanol, 0.3 g of quaternized polyethyleneimine functionalized graphene oxide was added, and magnetic stirring was performed for 30 min to obtain a uniform dispersion of quaternized polyethyleneimine functionalized graphene oxide in epoxy resin. Then, the ethanol was completely evaporated by rotary evaporation in a rotary evaporator for 45 min. 2.5 g of diluent was added dropwise and stirred for 30 min to reduce the viscosity of the epoxy resin. Then, 5 g of polyamide curing agent and 0.2 mL of defoamer were added to the above solution, and stirring was continued for 30 min. After the coating was evenly mixed, a quaternized polyethyleneimine functionalized graphene oxide reinforced epoxy resin with a mass fraction of 3 wt.% was obtained.

[0044] Comparative Example 1

[0045] A coating, which differs from Example 1 only in that graphene oxide is used instead of quaternized polyethyleneimine functionalized graphene oxide.

[0046] Comparative Example 2

[0047] A coating, which differs from Example 1 only in that quaternary ammonium polyethyleneimine is used instead of quaternary ammonium polyethyleneimine functionalized graphene oxide.

[0048] Comparative Example 3

[0049] A coating, which is different from Example 1 only in that quaternized polyethyleneimine functionalized graphene oxide is not added.

[0050] Performance Testing

[0051] (1) Anti-corrosion performance test:

[0052] The coatings described in Examples 1-3 and Comparative Examples 1-3 were respectively applied to the surface of a metal substrate, placed at room temperature for 5 days, and cured at 80°C for 3 hours to obtain a working electrode. The electrochemical behavior of the coating in a 3.5wt% NaCl solution was monitored using an electrochemical workstation and a three-electrode system consisting of a working electrode (coated electrode), a reference electrode (saturated calomel electrode), and a counter electrode (platinum electrode). The open circuit potential was maintained for 20 minutes to reach a stable state, and the corrosion potential of the working electrode was obtained. Detailed data are shown in Table 1 below.

[0053] Table 1 Corrosion potential

[0054]

[0055] The higher the open circuit potential, the more difficult it is for corrosion to occur. As shown in Table 1, the open circuit potential of the epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide is significantly higher than that of the comparative example, indicating that it has high corrosion resistance. When the addition amount of quaternized polyethyleneimine functionalized graphene oxide is 2wt%, the corrosion resistance of the composite coating is the best.

[0056] (2) Antibacterial performance test:

[0057] Escherichia coli was inoculated into peptone for activation and then the activated Escherichia coli suspension was added to a sterile culture dish, and a culture medium and a phosphate buffer solution were added. The mixture was cultured at 37°C for 24 hours. The samples with the coatings described in Examples 1-3 and Comparative Examples 1-3 were used as test samples, and the samples without any addition were used as blank samples. After culture, the number of viable bacteria in the test samples and blank samples was determined, and the inhibition rate was calculated. The results are shown in FIG. Figure 1 , 2 As shown in Table 2.

[0058] Table 2 Antibacterial effect

[0059] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Antibacterial rate 90.3％ 93.7％ 98.9％ 61.5％ 85.4％ No antibacterial effect

[0060] As shown in Table 2, the epoxy resin enhanced by quaternary polyethyleneimine functionalized graphene oxide exhibits excellent antibacterial properties, and the antibacterial rate increases with the increase of the content of quaternary polyethyleneimine functionalized graphene oxide. The antibacterial properties of epoxy resin enhanced by quaternary polyethyleneimine functionalized graphene oxide mainly come from the fact that the cations of quaternary polyethyleneimine can destroy the cell membrane structure of bacteria, hinder the ion exchange and material exchange between bacteria and the outside world, and then cause the death of bacteria. Secondly, the sharp edges of graphene oxide can pierce the cell wall and cell membrane, causing cell damage and death.

[0061] The above test results show that the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin of the present invention has excellent anticorrosion and antibacterial effects, and has great application prospects in the field of housing coatings for household appliances.

Claims

1. A method for preparing an anticorrosive and antibacterial coating, characterized in that: The invention comprises the steps of preparing quaternized polyethyleneimine functionalized graphene oxide and preparing epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide; the preparation step of epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide comprises: obtaining epoxy resin enhanced by quaternized polyethyleneimine functionalized graphene oxide by covalent reaction between amino groups of quaternized polyethyleneimine functionalized graphene oxide and epoxy resin.

2. The method for preparing the anticorrosive and antibacterial coating according to claim 1, characterized in that: The preparation steps of the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin specifically include: adding the quaternized polyethyleneimine functionalized graphene oxide to the dissolved epoxy resin, stirring to obtain a uniform dispersion, rotary evaporating the uniform dispersion, adding a diluent, stirring, and then adding a polyamide curing agent and a defoaming agent to obtain the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin.

3. The method for preparing the anticorrosive and antibacterial coating according to claim 1, characterized in that: The preparation steps of the quaternized polyethyleneimine functionalized graphene oxide include: adding graphene oxide, quaternized polyethyleneimine and N,N'-dicyclohexylcarbodiimide to N,N-dimethylformamide, performing ultrasonic treatment in an ice bath to completely dissolve the graphene oxide to obtain a mixed solution, heating the mixed solution in a water bath to fully react, washing and drying the mixed solution to obtain the quaternized polyethyleneimine functionalized graphene oxide.

4. The method for preparing the anticorrosive and antibacterial coating according to claim 2, characterized in that: The epoxy resin is selected from any one of E-31, E-35, E-42, E-44, E-51, and E-55.

5. The method for preparing the anticorrosive and antibacterial coating according to claim 2, characterized in that: In the step of preparing the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin, the diluent is a mixed solution of xylene and n-butanol.

6. The method for preparing the anticorrosive and antibacterial coating according to claim 2, characterized in that: The defoaming agent in the preparation step of the quaternized polyethyleneimine functionalized graphene oxide enhanced epoxy resin is a silicone defoaming agent.

7. The method for preparing the anticorrosive and antibacterial coating according to claim 3, characterized in that: The average sheet diameter of the graphene oxide in the quaternized polyethyleneimine functionalized graphene oxide preparation step is any value in the range of 0.5-5 μm.

8. An anticorrosive and antibacterial coating, characterized in that: The anticorrosion and antibacterial coating is prepared by the preparation method of any one of claims 1 to 7, wherein the anticorrosion and antibacterial coating is an epoxy resin reinforced with quaternized polyethyleneimine functionalized graphene oxide, and a covalent reaction occurs between the amino group of the quaternized polyethyleneimine functionalized graphene oxide in the epoxy resin reinforced with quaternized polyethyleneimine functionalized graphene oxide and the epoxy resin.

9. The use of the anticorrosive and antibacterial coating according to claim 8 in household appliance housing coatings, characterized in that: The anticorrosive and antibacterial coating forms a coating with a thickness of 100±10 μm on the surface of the housing of the household appliance.

10. A household appliance, characterized in that: The surface of the household appliance housing is covered with a coating formed by the anticorrosive and antibacterial coating according to claim 8.

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