Acrylic acid antibacterial emulsion containing modified chitosan and preparation method thereof

Abstract

The invention relates to an acrylic acid antibacterial emulsion containing modified chitosan and a preparation method of the acrylic acid antibacterial emulsion, and the acrylic acid antibacterial emulsion containing modified chitosan comprises the following components: an acrylic acid emulsion, modified polyacrylate, modified chitosan, a thickening agent, polyurethane, nano-silver particles and water; the acrylic antibacterial emulsion provided by the invention is prepared by compounding the components such as acrylic emulsion, modified polyacrylate, modified chitosan, nano-silver particles and the like, nano-silver is subjected to hydroxylation treatment by the modified polyacrylate and then is mixed with acrylic acid, and the acrylic acid is grafted on the nano-silver; according to the invention, nano-silver is taken as a raw material, and then free radical polymerization with acrylate is carried out under the catalysis of BPO, so that polymer chain segments are introduced on the surface of the nano-silver, nano-silver particles can exist in a coating more stably, the agglomeration phenomenon of nano-materials is reduced, and the stability and antibacterial durability of the coating are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to an acrylic antibacterial emulsion containing modified chitosan and a preparation method thereof. Background Art

[0002] As people pay more attention to health and the environment, coatings with antibacterial functions have been widely used in many fields such as construction, medical treatment, and home furnishing. Antibacterial coatings can not only inhibit the growth of harmful microorganisms and reduce the spread of bacteria, but also extend the service life of the surface of objects. Therefore, the research and development of antibacterial coatings has become one of the important directions of the coatings industry.

[0003] Common antibacterial coatings on the market usually achieve antibacterial effects by adding antibacterial agents. Common antibacterial agents include organic antibacterial agents, metal ion antibacterial agents and nanomaterials. Although traditional organic antibacterial agents such as benzoic acid and imidazoles have certain antibacterial effects, they are easily degraded during long-term use, and the antibacterial performance decays significantly. In addition, some organic antibacterial agents have potential toxic risks to the human body and the environment. In contrast, metal ion antibacterial agents (such as silver ions, copper ions, etc.) have a wide antibacterial spectrum and good stability, because they can continuously release metal ions to achieve long-term antibacterial effects. However, the preparation cost of metal ion antibacterial agents is high, and the release rate of metal ions is difficult to control. Excessive release may cause environmental pollution and health problems. In addition, nanomaterials such as nanosilver have received widespread attention in recent years. Due to their high antibacterial performance and small usage, they are gradually used in antibacterial coatings. However, nanomaterials have poor dispersibility in the coating matrix and are easy to agglomerate, affecting the uniformity and antibacterial effect of the coating.

[0004] In order to further improve the performance of antibacterial coatings, chitosan, as a natural polymer material, has attracted the attention of researchers. Chitosan not only has good biocompatibility and low toxicity, but also has certain antibacterial effects, so it is widely used in medical, food packaging and other fields. However, there are some limitations in the application of chitosan in coatings, mainly manifested in its poor water solubility, weak film-forming properties and limited antibacterial effects, which are difficult to meet actual application needs. Therefore, how to modify chitosan to improve its adaptability in coatings has become an important research direction.

[0005] In the prior art, certain progress has been made in the research and development of antibacterial coatings, but the following problems still exist: first, the antibacterial agent has poor dispersibility, resulting in uneven antibacterial properties in the coating, which in turn affects the overall antibacterial effect of the coating; second, traditional antibacterial agents are prone to lose their activity during long-term use, and the antibacterial effect cannot be sustained; finally, some antibacterial agents may have adverse effects on the environment or human body, restricting their safety in wide applications.

[0006] Therefore, it is necessary to develop a new technical solution to solve the deficiencies in the prior art. Summary of the invention

[0007] Based on this, the present invention prepares an acrylic antibacterial emulsion with excellent antibacterial properties by modifying chitosan and polyacrylate, in particular by utilizing the antibacterial properties of nanosilver, and grafting nanosilver onto the surfaces of chitosan and acrylate. This technology not only effectively solves the problem of the dispersibility of nanosilver in the coating, but also enhances the antibacterial effect of chitosan by modifying chitosan, prolongs the antibacterial time of the coating, and improves the biocompatibility and safety of the coating, thus overcoming the problems existing in the prior art.

[0008] An object of the present invention is to provide an acrylic antibacterial emulsion containing modified chitosan, wherein the acrylic antibacterial emulsion containing modified chitosan comprises the following components:

[0009]

[0010] The modified polyacrylate is a product formed by the polymerization of nanosilver grafted with acrylic acid and acrylic acid ester;

[0011] The modified chitosan is a product of chitosan with nano-silver grafted on its surface.

[0012] Specifically, by introducing polyurethane, the toughness and wear resistance of the coating are further improved, so that the antibacterial emulsion not only has excellent antibacterial properties, but also can adapt to various harsh use environments, thereby extending the service life of the coating.

[0013] Specifically, nanosilver has a broad-spectrum antibacterial property. Its highly efficient antibacterial ability can inhibit the growth of a variety of pathogens, prolong the antibacterial time of the coating, and ensure that it can maintain a good antibacterial effect during long-term use.

[0014] Furthermore, the acrylic emulsion is selected from one or more of hydroxypropyl emulsion, styrene-acrylic emulsion and pure acrylic emulsion.

[0015] Furthermore, the particle size of the nanosilver particles is 1-100 nm.

[0016] Furthermore, the acrylic acid ester is selected from one or more of methyl acrylate, butyl acrylate, propyl acrylate and ethyl acrylate.

[0017] Furthermore, the molecular weight of the chitosan is 5000-50000.

[0018] Specifically, chitosan is a natural biopolymer with good biocompatibility, and chitosan is rich in sources, renewable, and low in toxicity, meeting the needs of modern environmental protection and sustainable development. At the same time, the content of nano silver particles is strictly controlled within a safe range, which not only ensures antibacterial properties, but also avoids the risks that excessive release of silver ions may bring to the environment and human health. Therefore, the antibacterial emulsion prepared by the present invention has high safety when used in various environments, and is suitable for fields with high safety requirements such as food processing, medical equipment, and household daily necessities.

[0019] The present invention also provides a method for preparing the acrylic antibacterial emulsion containing modified chitosan, and the preparation method of the modified polyacrylate is as follows:

[0020] S1. mixing hydroxylated nanosilver and methacrylic acid, and then ultrasonically heating to obtain an intermediate product;

[0021] S2. The intermediate product and acrylic acid ester are heated in a solvent, and free radical polymerization is carried out under the catalysis of BPO to obtain a product.

[0022] Furthermore, in step S2, the molar ratio of the intermediate product to the acrylic ester is 1:1-1:3.

[0023] Furthermore, in step S1, the heating temperature is 70-80°C.

[0024] Furthermore, in step S2, the heating temperature is 70-95°C.

[0025] Furthermore, the preparation method of the modified chitosan is:

[0026] A1. Chitosan was mixed with water, lipoic acid, EDC and NHS were added thereto, the mixture was heated to react, and then dried to obtain an intermediate product 2;

[0027] A2. Sodium borohydride and sodium citrate were added to the silver nitrate solution, and the reaction was stirred in the dark to obtain an intermediate product 3;

[0028] A3. Add the intermediate product 2 to the system of the intermediate product 3, react at room temperature, and obtain the modified chitosan.

[0029] Specifically, nanosilver, with its broad-spectrum and highly effective antibacterial properties, can quickly kill or inhibit the growth of a variety of pathogens (such as Escherichia coli, Staphylococcus aureus, etc.). This grafting modification allows nanosilver to be stably present in the coating and is not easy to fall off or become ineffective, thus ensuring that the coating maintains a good antibacterial effect for a long time.

[0030] Furthermore, in step A1, the heating temperature is 30-50°C.

[0031] The present invention has the following beneficial effects:

[0032] The acrylic antibacterial emulsion provided by the present invention is obtained by compounding components such as acrylic emulsion, modified polyacrylate, modified chitosan, and nano silver particles; the modified polyacrylate first performs hydroxylation treatment on nano silver, then reacts with acrylic acid, grafts acrylic acid on nano silver, and then performs free radical polymerization with acrylate under the catalysis of BPO, thereby introducing polymer segments on the surface of nano silver, which not only enhances the antibacterial ability of the material, but also plays the role of a compatibilizer, improves the affinity between nano silver particles and components such as acrylic emulsion, reduces agglomeration, and further improves the stability and antibacterial durability of the coating. Modified chitosan not only enhances the antibacterial effect of chitosan itself by grafting nano silver onto the surface of chitosan, but also improves the compatibility of inorganic nano silver with acrylic emulsion and polyurethane, which is beneficial to improving the emulsification effect and film uniformity of the coating, and multiple components are cross-linked and entangled through active groups to form a synergistic effect, which greatly improves the uniformity, stability and overall antibacterial effect of the coating. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the technical solution of the present invention, the following examples are listed. Unless otherwise stated, the raw materials, reactions and post-treatment methods shown in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0034] The words "preferred", "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0035] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers indicating, for example, the amounts of ingredients used in the specification and claims should be understood to be modified in all cases by the term "about". Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that vary depending on the desired properties to be obtained by the present invention.

[0036] The molecular weight of chitosan is 5000-50000, and the degree of deacetylation is >90%.

[0037] Acrylic emulsion, Wanhua Chemical, Archso18087.

[0038] Nanosilver particles, average particle size 100nm.

[0039] Polyurethane, Opdi, CUR995.

[0040] Thickener, Rohm and Haas, RM2020.

[0041] The "parts" in the embodiments of the present invention refer to parts by mass.

[0042] Example 1

[0043] An acrylic acid antibacterial emulsion containing modified chitosan, the acrylic acid antibacterial emulsion containing modified chitosan comprises the following components:

[0044]

[0045] The preparation method of the modified polyacrylate is:

[0046] S1-1. Add 1 part of nanosilver to 50 parts of 10mol / L NaOH solution and stir evenly, stir the reaction for 6h, filter and wash to obtain hydroxylated nanosilver;

[0047] S1-2. The hydroxylated nanosilver was added to 80 parts of toluene, and then 10 parts of methacrylic acid were added, heated at 70 ° C for 8h, filtered, washed and dried to obtain an intermediate product;

[0048] S2. Using toluene as solvent, 5 parts of the intermediate product and 10 parts of butyl acrylate were mixed, and then a catalyst BPO (the amount of BPO was 1% of the total mass of the reaction raw materials) was added, and the mixture was heated to 80° C. for 2 h under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled and distilled under reduced pressure to remove unreacted substances and impurities, and the modified polyacrylate was obtained by washing, filtering and drying;

[0049] The preparation method of the modified chitosan is:

[0050] A1. Chitosan was added to deionized water to prepare a 0.02 mol / L solution, and then 5% lipoic acid was added to the chitosan amino group, and then EDC and NHS were added in an equal amount to the lipoic acid, and the reaction was carried out at 30°C for 4 hours, dialyzed, and then freeze-dried to obtain an intermediate product 2;

[0051] A2. Add 0.067 mol / L sodium borohydride solution (volume ratio of 1:3) and an equimolar amount of sodium citrate to 0.1 mol / L silver nitrate solution, stir and react for 2 h in dark to obtain an intermediate product 3;

[0052] A3. The intermediate product 2 is added to the intermediate product 3 system (molar ratio is 1:1), and the reaction is carried out at room temperature for 0.5h to obtain the modified chitosan;

[0053] The method for preparing the acrylic antibacterial emulsion containing modified chitosan comprises the following steps:

[0054] The modified chitosan, modified polyacrylate and other ingredients are blended according to the above mass fractions to obtain the acrylic antibacterial emulsion containing modified chitosan.

[0055] Example 2

[0056] An acrylic acid antibacterial emulsion containing modified chitosan, the acrylic acid antibacterial emulsion containing modified chitosan comprises the following components:

[0057]

[0058] The preparation method of the modified polyacrylate is:

[0059] S1-1. Add 1 part of nanosilver to 50 parts of 10mol / L NaOH solution and stir evenly, stir the reaction for 6h, filter and wash to obtain hydroxylated nanosilver;

[0060] S1-2. The hydroxylated nanosilver was added to 80 parts of toluene, and then 10 parts of methacrylic acid were added, heated at 70 ° C for 8h, filtered, washed and dried to obtain an intermediate product;

[0061] S2. Using toluene as solvent, 5 parts of the intermediate product and 10 parts of butyl acrylate were mixed, and then a catalyst BPO (the amount of BPO was 1% of the total mass of the reaction raw materials) was added, and the mixture was heated to 80° C. for 2 h under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled and distilled under reduced pressure to remove unreacted substances and impurities, and the modified polyacrylate was obtained by washing, filtering and drying;

[0062] The preparation method of the modified chitosan is:

[0063] A1. Chitosan was added to deionized water to prepare a 0.02 mol / L solution, and then 5% lipoic acid was added to the chitosan amino group, and then EDC and NHS were added in an equal amount to the lipoic acid, and the reaction was carried out at 30°C for 4 hours, dialyzed, and then freeze-dried to obtain an intermediate product 2;

[0064] A2. Add 0.067 mol / L sodium borohydride solution (volume ratio of 1:3) and an equimolar amount of sodium citrate to 0.1 mol / L silver nitrate solution, stir and react for 2 h in dark to obtain an intermediate product 3;

[0065] A3. Add the intermediate product 2 to the system of the intermediate product 3 (molar ratio is 1:1), react at room temperature for 0.5h, and obtain the modified chitosan.

[0066] The method for preparing the acrylic antibacterial emulsion containing modified chitosan comprises the following steps:

[0067] The modified chitosan, modified polyacrylate and other ingredients are blended according to the above mass fractions to obtain the acrylic antibacterial emulsion containing modified chitosan.

[0068] Example 3

[0069] An acrylic acid antibacterial emulsion containing modified chitosan, the acrylic acid antibacterial emulsion containing modified chitosan comprises the following components:

[0070]

[0071] The preparation method of the modified polyacrylate is:

[0072] S1-1. Add 1 part of nanosilver to 50 parts of 10mol / L NaOH solution and stir evenly, stir the reaction for 6h, filter and wash to obtain hydroxylated nanosilver;

[0073] S1-2. The hydroxylated nanosilver was added to 80 parts of toluene, and then 10 parts of methacrylic acid were added, heated at 70 ° C for 8h, filtered, washed and dried to obtain an intermediate product;

[0074] S2. Using toluene as solvent, 5 parts of the intermediate product and 10 parts of butyl acrylate were mixed, and then a catalyst BPO (the amount of BPO was 1% of the total mass of the reaction raw materials) was added, and the mixture was heated to 80° C. for 2 h under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled and distilled under reduced pressure to remove unreacted substances and impurities, and the modified polyacrylate was obtained by washing, filtering and drying;

[0075] The preparation method of the modified chitosan is:

[0076] A1. Chitosan was added to deionized water to prepare a 0.02 mol / L solution, and then 5% lipoic acid was added to the chitosan amino group, and then EDC and NHS were added in an equal amount to the lipoic acid, and the reaction was carried out at 30°C for 4 hours, dialyzed, and then freeze-dried to obtain an intermediate product 2;

[0077] A2. Add 0.067 mol / L sodium borohydride solution (volume ratio of 1:3) and an equimolar amount of sodium citrate to 0.1 mol / L silver nitrate solution, stir and react for 2 h in dark to obtain an intermediate product 3;

[0078] A3. The intermediate product 2 is added to the intermediate product 3 system (molar ratio is 1:1), and the reaction is carried out at room temperature for 0.5h to obtain the modified chitosan;

[0079] The method for preparing the acrylic antibacterial emulsion containing modified chitosan comprises the following steps:

[0080] The modified chitosan, modified polyacrylate and other ingredients are blended according to the above mass fractions to obtain the acrylic antibacterial emulsion containing modified chitosan.

[0081] Comparative Example 1

[0082] The difference between this comparative example and Example 1 is that the modified chitosan is replaced by unmodified chitosan, and the other components and preparation method are the same as those in Example 1.

[0083] Comparative Example 2

[0084] The difference between this comparative example and Example 1 is that step S1 is removed, and the intermediate product is replaced by methyl methacrylate or the like in step S2. The other components and preparation method are the same as those in Example 1.

[0085] Test Case

[0086] The performance of the acrylic antibacterial emulsions prepared in Example 1 and Comparative Examples 1-2 was tested.

[0087] Test method:

[0088] Antibacterial rate: The acrylic antibacterial emulsions of Example 1 and Comparative Examples 1-2 were respectively coated on the surface of the strip test specimens, and the antibacterial performance was tested according to GB / T21866-2008 "Determination of antibacterial properties and antibacterial effects of antibacterial coatings (paint films)", and the antibacterial rates of the acrylic antibacterial emulsions against Escherichia coli and Staphylococcus aureus were tested.

[0089] Stability test:

[0090] High temperature stability: The acrylic antibacterial emulsions prepared in Example 1 and Comparative Examples 1-2 were respectively packaged and sealed, placed in a 48°C environment, and kept at a constant temperature for 3 months, and then returned to room temperature of 25°C. There was no significant change in the appearance of the acrylic antibacterial emulsion, and no stratification, turbidity or precipitation was observed, indicating that the high temperature stability was qualified.

[0091] Low temperature stability: The acrylic antibacterial emulsions prepared in Example 1 and Comparative Examples 1-2 were respectively packaged and sealed, placed in a -5°C environment, kept at a constant temperature for 4 weeks, and then returned to room temperature 25°C. There was no significant change in the appearance of the acrylic antibacterial emulsion, no stratification, turbidity or precipitation, and the low temperature stability was qualified.

[0092] The test results are shown in Table 1.

[0093] Table 1 Performance test results of acrylic antibacterial emulsions of Example 1 and Comparative Examples 1-2

[0094]

[0095]

[0096] It can be seen from the test results in the above table that the acrylic antibacterial emulsion of the present invention has obvious advantages in antibacterial performance compared with comparative examples 1-2; in the stability test, after the acrylic antibacterial emulsion of the present invention is placed at high and low temperatures for a long time, the performance of the acrylic antibacterial emulsion is still maintained at a stable level, and the compatibility between the components is good, while the acrylic antibacterial emulsion of the comparative example shows stratification and precipitation.

[0097] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0098] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An acrylic antibacterial emulsion containing modified chitosan, characterized in that: The acrylic acid antibacterial emulsion containing modified chitosan comprises the following components: water; The modified polyacrylate is a product formed by the polymerization of nanosilver grafted with acrylic acid and acrylic acid ester; The modified chitosan is a product of chitosan with nano-silver grafted on its surface.

2. The acrylic antibacterial emulsion containing modified chitosan according to claim 1, characterized in that: The acrylic emulsion is selected from one or more of hydroxypropyl emulsion, styrene-acrylic emulsion and pure acrylic emulsion.

3. The acrylic antibacterial emulsion containing modified chitosan according to claim 1, characterized in that: The particle size of the nano silver particles is 1-100 nm.

4. The acrylic antibacterial emulsion containing modified chitosan according to claim 1, characterized in that: The acrylate is selected from one or more of methyl acrylate, butyl acrylate, propyl acrylate and ethyl acrylate.

5. The acrylic antibacterial emulsion containing modified chitosan according to claim 1, characterized in that: The molecular weight of the chitosan is 5000-50000.

6. The method for preparing the acrylic antibacterial emulsion containing modified chitosan according to any one of claims 1 to 5, characterized in that: The preparation method of the modified polyacrylate is: S1. mixing hydroxylated nanosilver and methacrylic acid, and then ultrasonically heating to obtain an intermediate product; S2. The intermediate product and acrylic acid ester are heated in a solvent, and free radical polymerization is carried out under the catalysis of BPO to obtain a product.

7. The method for preparing the acrylic antibacterial emulsion containing modified chitosan according to claim 6, characterized in that: In step S2, the molar ratio of the intermediate product to the acrylate is 1:1-1:

3.

8. The method for preparing the acrylic antibacterial emulsion containing modified chitosan according to claim 6, characterized in that: In step S1, the heating temperature is 70-80°C; In step S2, the heating temperature is 70-95°C.

9. The method for preparing the acrylic antibacterial emulsion containing modified chitosan according to claim 6, characterized in that: The preparation method of the modified chitosan is: A1. Chitosan was mixed with water, lipoic acid, EDC and NHS were added thereto, the mixture was heated to react, and then dried to obtain an intermediate product 2; A2. Sodium borohydride and sodium citrate were added to the silver nitrate solution, and the reaction was stirred in the dark to obtain an intermediate product 3; A3. Add the intermediate product 2 to the system of the intermediate product 3, react at room temperature, and obtain the modified chitosan.

10. The method for preparing the acrylic antibacterial emulsion containing modified chitosan according to claim 9, characterized in that: In step A1, the heating temperature is 30-50°C.

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