Antibacterial and mildew-proof EVA composite material and preparation method thereof

Abstract

The application discloses an antibacterial and mildew-proof EVA composite material and a preparation method thereof. The EVA composite material is prepared from EVA resin, an antibacterial agent, an initiator, a heat stabilizer, a lubricant and a filler as raw materials. The antibacterial agent is prepared by first preparing 4-propyleneoxy-2-hydroxybenzophenone modified by amino through a liquid phase modification method, and then grafting ferulic acid on the 4-propyleneoxy-2-hydroxybenzophenone through a Schiff base reaction. The antibacterial agent has enhanced antioxidation by introducing ferulic acid, and the introduced ferulic acid and Schiff base structure have good mildew-proof and broad-spectrum antibacterial effects. Meanwhile, the antibacterial agent is embedded on the main chain of the EVA in a chemical bond mode through the action of the initiator, so that the loss caused by the migration, volatilization and extraction of the antibacterial agent can be prevented, and the long-term antibacterial and mildew-proof effect of the composite material is ensured.

Description

Technical Field

[0001] This invention belongs to the field of composite materials, specifically relating to an antibacterial and antifungal EVA composite material and its preparation method. Background Technology

[0002] EVA resin, short for ethylene-vinyl acetate copolymer resin, possesses excellent mechanical properties, chemical stability, and good biocompatibility, and has been widely used in footwear foaming, wire and cable, films, and even food and medical fields. However, bacteria, mold, and other pathogenic microorganisms can grow and accumulate on the surface of EVA products over prolonged use, which can pose a certain degree of harm to human health. Therefore, to solve this problem and protect people's health and quality of life, it is necessary to modify EVA materials for antibacterial properties to prepare EVA composite materials with good antibacterial and antifungal effects.

[0003] Currently, the most commonly used inorganic antibacterial agents are silver ion-based antibacterial agents. However, because they are inorganic powders, they have poor compatibility with EVA. This results in antibacterial EVA composites that, while possessing some antibacterial function, are prone to detachment and lack long-lasting antibacterial effect. Ferulic acid, on the other hand, is a substance with excellent antioxidant activity, exhibiting strong scavenging effects against hydrogen peroxide, superoxide radicals, hydroxyl radicals, and peroxide nitrosamines. In addition to its strong antioxidant activity, ferulic acid also possesses potent antibacterial activity. It has been found that ferulic acid can inhibit the growth of pathogenic bacteria such as Shigella sonnei, Klebsiella pneumoniae, Enterobacter, Escherichia coli, Citrobacter, and Pseudomonas aeruginosa, as well as 11 types of microorganisms that cause food spoilage.

[0004] This invention enhances the antioxidant properties of the antibacterial agent by amino-modifying the ultraviolet absorber 4-propenoxy-2-hydroxybenzophenone (AHB) and then combining it with ferulic acid through a Schiff base reaction. This makes the composite material less susceptible to oxidation. In addition, the antibacterial agent is chemically bonded to the main chain of EVA, which can prevent loss caused by the migration, volatilization and extraction of the antibacterial agent, thus ensuring that the composite material has long-lasting antibacterial and antifungal properties. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an antibacterial and antifungal EVA composite material and its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An antibacterial and antifungal EVA composite material is made from EVA resin, antibacterial agent, initiator, heat stabilizer, lubricant and filler. The total mass of EVA resin and antibacterial agent is 100%, with the initiator accounting for 0.1%-2%, the heat stabilizer for 0.5%, the lubricant for 1.5%, and the filler for 0.2%. The mass percentage ratio of EVA resin to antibacterial agent is (98-99.9):(0.1-2).

[0008] Furthermore, the EVA resin has a VA content of 6% and a melt index of 28 g / 10 min.

[0009] Furthermore, the initiator is dicumyl peroxide (DCP).

[0010] Furthermore, the heat stabilizer is calcium stearate.

[0011] Furthermore, the lubricant is polyethylene wax.

[0012] Furthermore, the filler is talc.

[0013] Furthermore, the antibacterial agent is prepared by first modifying the surface of 4-propenoxy-2-hydroxybenzophenone (AHB) with 3-aminopropyltrimethoxysilane via liquid-phase modification to obtain amino-modified 4-propenoxy-2-hydroxybenzophenone (AHB-NH2), and then grafting ferulic acid onto it via Schiff base reaction; the specific steps are as follows:

[0014] a) 4-Acryloxy-2-hydroxybenzophenone (AHB) was dispersed in toluene, and then 3-aminopropyltrimethoxysilane was added. After stirring at 50°C for 3 hours, the mixture was washed multiple times with toluene and then dried to obtain amino-modified 4-acryloxy-2-hydroxybenzophenone (AHB-NH2).

[0015] b) Dissolve the obtained AHB-NH2 in N,N-dimethylformamide (DMF), add ferulic acid, heat and reflux at 60°C for 2 hours, then wash away the unreacted ferulic acid with ethanol to obtain the antibacterial agent AHB-NH2-FA.

[0016] The molar ratio of 3-aminopropyltrimethoxysilane, 4-propenoxy-2-hydroxybenzophenone and ferulic acid used is 3:1:1.

[0017] The preparation method of the antibacterial and antifungal EVA composite material includes the following steps:

[0018] 1) Weigh out the EVA resin, antibacterial agent, initiator, heat stabilizer, lubricant and filler according to the formula, and stir at high speed to mix them evenly to obtain a mixture;

[0019] 2) The obtained mixture is poured into a twin-screw extruder for extrusion granulation, and then dried to obtain the antibacterial and mildew-resistant EVA composite material.

[0020] Further, in step 1), the high-speed stirring speed is 230 rpm and the time is 30 min.

[0021] Furthermore, in step 2), the twin-screw extruder used has a rotational speed of 200-300 rpm and an extrusion barrel temperature of 120-150 ℃.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention enhances the antioxidant properties of the antibacterial agent by introducing ferulic acid. The introduced ferulic acid and Schiff base structure have good antifungal and broad-spectrum antibacterial effects. At the same time, through interaction with the initiator, the antibacterial agent is chemically bonded into the main chain of EVA, which can prevent losses caused by the migration, volatilization and extraction of the antibacterial agent. Thus, while ensuring that the obtained EVA composite material has the original UV resistance, it also has long-lasting antibacterial and antifungal properties. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the reaction process for preparing the antibacterial agent according to the present invention.

[0025] Figure 2 This is a schematic diagram of the reaction in which the antibacterial agent of the present invention is embedded in the EVA main chain.

[0026] Figure 3 The image shows a comparison of the infrared spectra of AHB-NH2, AHB-NH2-FA, and AHB prepared in the examples. Detailed Implementation

[0027] An antibacterial and antifungal EVA composite material is prepared by the following steps:

[0028] 1) EVA resin and antibacterial agent are mixed in a mass percentage ratio of (98-99.9):(0.1-2). Then, 0.1%-2% of the total mass of EVA resin and antibacterial agent, 0.5% of the initiator dicumyl peroxide (DCP), 1.5% of the heat stabilizer calcium stearate, 1.5% of the lubricant polyethylene wax, and 0.2% of the filler talc are weighed. All raw materials are added to a high-speed mixer and stirred at 230 rpm for 30 min to make them evenly mixed to obtain a mixture.

[0029] 2) Pour the obtained mixture into a twin-screw extruder and granulate it at a speed of 200-300 rpm. The extruder barrel temperature is 120-150 ℃. After drying, the antibacterial and mildew-resistant EVA composite material is obtained.

[0030] The EVA resin has a VA content of 6% and a melt index of 28 g / 10 min.

[0031] The preparation of the antibacterial agent includes the following steps:

[0032] 1) 4-Propyleneoxy-2-hydroxybenzophenone was dispersed in toluene, and then a certain amount of 3-aminopropyltrimethoxysilane was added. After stirring and reacting at 50°C for 3 hours, the mixture was washed multiple times with toluene and then dried to obtain AHB-NH2.

[0033] 2) Dissolve AHB-NH2 in an appropriate amount of N,N-dimethylformamide (DMF), add a certain amount of ferulic acid, heat and reflux at 60°C for 2 hours, and then wash away the unreacted ferulic acid with ethanol to obtain the antibacterial agent AHB-NH2-FA.

[0034] Figure 3 The image shows a comparison of the infrared spectra of the prepared AHB-NH2, AHB-NH2-FA, and AHB. Figure 3 It can be seen that, compared to AHB, AHB-NH2 at 1480 cm⁻¹ −1 and 2930 cm −1 A new absorption peak appeared at 1480 cm⁻¹. −1 The deformation vibration peak of -NH2; 2930 cm⁻¹ −1 The peak at 3420 cm⁻¹ corresponds to the stretching vibration of the methylene group (CH₂). This result indicates that the amino group was successfully introduced into AHB. In contrast, AHB-NH₂-FA shows a peak at 3420 cm⁻¹. −1 The appearance of a stretching vibration peak of -OH indicates that ferulic acid and AHB-NH2 have successfully reacted to produce AHB-NH2-FA.

[0035] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0036] Example 1:

[0037] This embodiment provides an antibacterial and antifungal EVA composite material, the preparation of which includes the following steps:

[0038] 1) EVA resin and antibacterial agent were mixed in a mass percentage ratio of 99.9:0.1. Then, 0.3% of DCP, 0.5% of calcium stearate, 1.5% of polyethylene wax and 0.2% of talc were weighed out of the total mass of EVA resin and antibacterial agent. All raw materials were added to a high-speed mixer and stirred at 230 rpm for 30 min to make them evenly mixed to obtain a mixture.

[0039] 2) Pour the obtained mixture into a twin-screw extruder and perform thermomechanical mixing, reaction, extrusion (extruder barrel temperature is 120℃) at a speed of 250 rpm, cool and pelletize, and then dry to obtain antibacterial and mildew-resistant EVA composite material.

[0040] Example 2:

[0041] This embodiment provides an antibacterial and antifungal EVA composite material, in which the amount of EVA resin is 99.5% and the amount of antibacterial agent AHB-NH2-FA is 0.5%, and other contents are the same as in Embodiment 1.

[0042] Example 3:

[0043] This embodiment provides an antibacterial and antifungal EVA composite material, in which the amount of EVA resin is 99% and the amount of antibacterial agent AHB-NH2-FA is 1.0%, and other contents are the same as in Embodiment 1.

[0044] Example 4:

[0045] This embodiment provides an antibacterial and antifungal EVA composite material, in which the amount of EVA resin is 98%, the amount of antibacterial agent AHB-NH2-FA is 2.0%, and other contents are the same as in Embodiment 1.

[0046] Comparative Example 1:

[0047] This comparative example provides an antibacterial and antifungal EVA material, which uses common inorganic silver ions (Langyi B130) as an antibacterial agent. Other contents are the same as in Example 4.

[0048] Comparative Example 2:

[0049] This comparative example provides an antibacterial and antifungal EVA composite material, which uses 4-propenoxy-2-hydroxybenzophenone (AHB) as an antibacterial agent, and other contents are the same as in Example 4.

[0050] Comparative Example 3:

[0051] This comparative example provides an antibacterial and antifungal EVA composite material, which uses ferulic acid as an antibacterial agent, and other contents are the same as in Example 4.

[0052] Comparative Example 4:

[0053] This comparative example provides an antibacterial and antifungal EVA composite material, which uses 4-propenoxy-2-hydroxybenzophenone (AHB) and ferulic acid mixed in a molar ratio of 1:1 as an antibacterial agent. Other contents are the same as in Example 4.

[0054] The antibacterial properties (using Escherichia coli as the test strain) and antifungal properties (using Aspergillus niger ATCC 6275, Chaetomium globulus ATCC 6205, etc. as test strains to construct a moldy environment) of the EVA materials obtained in the examples and comparative examples were tested, and the results are shown in Table 1.

[0055] Table 1. Antibacterial and antifungal properties of different EVA materials

[0056]

[0057] As can be seen from the comparison between the examples in Table 1 and Comparative Example 1, the antibacterial agent AHB-NH2-FA of the present invention can enhance the antibacterial properties of the agent itself by introducing ferulic acid and Schiff base structures, so that a smaller amount of antibacterial agent can be used to maintain good antibacterial properties.

[0058] A comparison of Example 4 and Comparative Example 2 shows that, since AHB is only an ultraviolet light absorber, the composite material prepared by adding only AHB does not have antibacterial and antifungal properties.

[0059] A comparison of Example 4 with Comparative Examples 3 and 4 shows that, compared with the simple physical blending of EVA with ferulic acid alone and blends of AHB and ferulic acid, the present invention embeds the antibacterial agent AHB-NH2-FA into the main chain of EVA by means of chemical bonds, which solves the compatibility problem between the antibacterial agent and EVA, and ensures that the antibacterial agent will not migrate, volatilize or be extracted and lost. Thus, a better and longer-lasting antibacterial and antifungal effect can be achieved with less antibacterial agent.

[0060] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. An antibacterial and antifungal EVA composite material, characterized in that: The composite material is made from EVA resin, antibacterial agent, initiator, heat stabilizer, lubricant and filler. Of which, based on the total mass of EVA resin and antibacterial agent as 100%, the amount of initiator is 0.1%-2%, the amount of heat stabilizer is 0.5%, the amount of lubricant is 1.5%, and the amount of filler is 0.2%; the mass percentage ratio of EVA resin to antibacterial agent is (98-99.9):(0.1-2); The antibacterial agent is prepared by first modifying the surface of 4-propenoxy-2-hydroxybenzophenone with 3-aminopropyltrimethoxysilane in a liquid phase to obtain amino-modified 4-propenoxy-2-hydroxybenzophenone, and then grafting ferulic acid onto it through a Schiff base reaction; the Schiff base reaction is carried out by heating and refluxing at 60°C for 2 hours in N,N-dimethylformamide as solvent.

2. The antibacterial and antifungal EVA composite material according to claim 1, characterized in that: The EVA resin has a VA content of 6% and a melt index of 28 g / 10 min.

3. The antibacterial and antifungal EVA composite material according to claim 1, characterized in that: The molar ratio of 3-aminopropyltrimethoxysilane, 4-propenoxy-2-hydroxybenzophenone and ferulic acid used is 3:1:1; The liquid phase modification was performed at a temperature of 50°C for 3 hours.

4. The antibacterial and antifungal EVA composite material according to claim 1, characterized in that: The initiator is dicumyl peroxide.

5. The antibacterial and antifungal EVA composite material according to claim 1, characterized in that: The heat stabilizer is calcium stearate.

6. The antibacterial and antifungal EVA composite material according to claim 1, characterized in that: The lubricant is polyethylene wax.

7. The antibacterial and antifungal EVA composite material according to claim 1, characterized in that: The filler is talc.

8. A method for preparing an antibacterial and antifungal EVA composite material according to claim 1, characterized in that: Includes the following steps: 1) Weigh out the EVA resin, antibacterial agent, initiator, heat stabilizer, lubricant and filler according to the formula, and stir at high speed to mix them evenly to obtain a mixture; 2) The obtained mixture is poured into a twin-screw extruder for extrusion granulation, and then dried to obtain the antibacterial and mildew-resistant EVA composite material.

9. The method for preparing the antibacterial and antifungal EVA composite material according to claim 8, characterized in that: The high-speed stirring speed is 230 rpm and the time is 30 min; the speed of the twin-screw extruder used is 200-300 rpm and the extrusion barrel temperature is 120-150 ℃.

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