CN120818139A - Organic antibacterial agent and preparation method thereof - Google Patents

Abstract

The present invention discloses an organic antibacterial agent, which belongs to the field of antibacterial agent preparation. Modified polyhexamethylene guanidine is used as the main structure. By designing and modifying the R group in the organic antibacterial agent, the antibacterial agent has the characteristic of high temperature resistance, can be blended with PVC, and antibacterial PVC with antibacterial properties and good mechanical properties is prepared. The blending preparation includes the following steps: S1: mixing; S2: mixing; S3: plasticizing; S4: extrusion molding. The antibacterial PVC obtained by the above blending operation can be used for wallpaper, flooring, furniture surfaces, and household appliance surfaces, etc., has good antibacterial effect, and its mechanical properties are greatly improved compared with the existing antibacterial PVC. The product is not easy to turn yellow or break, has good quality, is widely used, and can be used for a long time.

Description

Organic antibacterial agent and preparation method thereof

Technical Field

The invention belongs to the field of preparation of antibacterial agents, and particularly relates to the technical field of organic antibacterial agents.

Background

Floor films are a common surface protective material that is widely used in commercial, residential and industrial environments to protect floors from abrasion, contamination and chemicals. Conventional floor films are generally made of polyvinyl chloride (PVC) or the like, and have limited ability to inhibit microorganisms such as bacteria and mold, although they play an important role in protecting the floor and beautifying the environment. In addition, conventional floor films often require frequent cleaning and sterilization, which not only increases maintenance costs, but also places a burden on the environment. Therefore, the PVC floor film with antibacterial property can effectively inhibit the growth of microorganisms, improve the sanitary level of the ground, reduce the frequency of cleaning and disinfection, thereby protecting the health of people, reducing the environmental burden and prolonging the service life of the floor.

Due to the relatively high processing temperatures (> 140 ℃) of PVC, PVC is generally given stable antimicrobial properties by the addition of metallic antimicrobial agents such as TiO ₂, nano silver particles, and other high temperature resistant antimicrobial agents. However, on the one hand, the addition of inorganic antibacterial agents often accompanies agglomeration effects, which are not beneficial to the processing and shaping of PVC materials, and also reduce the mechanical properties of the materials, and on the other hand, metallic inorganic antibacterial agents have the risk of falling off from PVC, which can be potentially toxic to the human body, for example, absorption of silver by the body can lead to toxic reactions and the formation of drug-resistant microorganisms, leading to sustained cytotoxicity.

Chinese patent publication No. CN203257055U, CN112341729A, CN112778664A and CN107446264A disclose a method for imparting a certain antibacterial effect to PVC floor films by adding a metal inorganic antibacterial agent. However, on the one hand, the addition of inorganic antibacterial agents often accompanies agglomeration effects, which are not beneficial to the processing and shaping of PVC materials, and also reduce the mechanical properties of the materials, and on the other hand, metallic inorganic antibacterial agents have the risk of falling off from PVC, which can be potentially toxic to the human body, for example, absorption of silver by the body can lead to toxic reactions and the formation of drug-resistant microorganisms, leading to sustained cytotoxicity.

The Chinese patent with the application number of CN201710264086.2 discloses a high-temperature-resistant modified polyhexamethylene guanidine, a preparation method and application thereof, wherein the preparation method takes polyhexamethylene guanidine as a raw material, a phenyl compound (benzoic acid, benzoyl chloride, methyl benzoate, phthalic anhydride or para-aminobenzoic acid) is added, the mass ratio of the phenyl compound to the polyhexamethylene guanidine is 0.001-0.01:1, grafting reaction is carried out under the protection of nitrogen, the reaction temperature is 120-180 ℃, stirring is carried out under normal pressure, the reaction is carried out for 1-5 hours, then the temperature is reduced to 80-100 ℃, and the product is obtained after discharging. It is mentioned in this application that polyhexamethylene guanidine has good antibacterial properties, but far from reaching the antibacterial standards of medical product grade, further improvement of antibacterial properties is required, and medical grade products need to be sterilized at high temperature when reused, but existing medical products with antibacterial properties can decrease antibacterial efficacy at high temperature. Furthermore, the invention obtains the organic antibacterial agent with high temperature resistance, long antibacterial time and good antibacterial effect by grafting and modifying the polyhexamethylene guanidine, and is used for medical products. Although this application uses phenyl compounds such as benzoic acid, benzoyl chloride, methyl benzoate, phthalic anhydride, para-aminobenzoic acid, etc. to graft modify polyhexamethylene guanidine, the organic antimicrobial agent of this application is clearly incapable of, or at least does not contemplate, blending with PVC at elevated temperatures. According to the structural formula of the organic antibacterial agent obtained in the specification, as shown in the following figure, R ₁＝H,COOH;R₂＝H,NH₂ in the structural formula, that is, the technical scheme of the application comprises modification at the ortho position (R ₁) and the para position (R ₂) of the phenyl compound, which leads to the increase of the ortho position effect, the electronic effect and the steric hindrance of R ₁、R₂, and further leads to the decrease of the mechanical property of the PVC film due to the oxidation sensitivity of amino, acid-base reaction possibly occurring in the preparation and blending processes, the increase of the internal molecular stress and the like.

The antibacterial and antiviral polyvinyl chloride artificial leather comprises a base cloth layer, an antibacterial PVC layer and an antiviral coating layer, wherein the antibacterial PVC layer comprises, by mass, 30-70 parts of PVC resin, 20-50 parts of plasticizer, 1-5 parts of stabilizer, 1-5 parts of modifier, 0.5-10 parts of antibacterial and antifungal agent and 0-2 parts of foaming agent. The preparation method of the antibacterial PVC layer sheet comprises the following steps of mixing and stirring the preparation raw materials of the antibacterial PVC layer in the high-speed mixer at a high speed according to the parts by weight, discharging into an internal mixer for mixing, wherein the mixing temperature is 100-150 ℃, discharging into an open mill after mixing, plasticating sequentially through two open mills at the temperature of 100-150 ℃, conveying to a calender for calendering into sheets, and calendering at the temperature of 120-180 ℃ to obtain the antibacterial PVC layer sheet. That is, the application mixes the antibacterial agent, the PVC resin, and other processing aids, and sequentially performs processing steps such as banburying, plasticating, calendaring, and the like, thereby realizing the compounding of the antibacterial agent and PVC, and producing a sheet. However, as can be seen from the description of the application, the added antibacterial mildew preventive is specifically formed by compounding silica coated silver nano particles (SiO ₂ -Ag) with a core-shell structure and carboxymethyl chitosan (CMC), and the antibacterial agent with the structure can be blended with PVC, but has the problems of poor dispersibility, poor interface compatibility, low processing stability, great influence on optical performance and the like due to the nano particles, and still has limited processability, and the release and lasting performance of the antibacterial agent in the blended PVC material cannot be ensured, so that the antibacterial performance and the mechanical strength of the antibacterial film cannot be simultaneously considered.

In summary, in the prior art, it is proposed to compound an antibacterial agent with PVC to obtain antibacterial PVC, but inorganic antibacterial agents cannot be well formed with PVC materials, mechanical properties of the materials are reduced, and toxic risks are caused by metal falling, yellowing of quaternary ammonium salt antibacterial agents occurs after a long time, organic antibacterial agents are generally not high-temperature resistant and poor in processing stability, yellowing and deformation occur in the process of blending with PVC, so that the process is complicated, the compound effect of the inorganic antibacterial agents and the PVC is poor, and the quality control of products is not facilitated. Therefore, how to make the combination effect of PVC and the antibacterial agent better, and make the mechanical property and the product quality better while guaranteeing the antibacterial effect of the antibacterial PVC, becomes a technical problem to be solved urgently by the technicians in the field.

Disclosure of Invention

Aiming at the problems that the antibacterial agent in the traditional floor film has poor thermal stability and poor combination effect with PVC, and the two are difficult in the compounding process, so that the antibacterial performance and the mechanical performance of the antibacterial PVC composite material cannot be considered, the first aim of the invention is to design an organic antibacterial agent which has better thermal stability and good compounding effect with PVC.

The second aim of the invention is to provide a preparation method of the antibacterial PVC, which can realize the blending processing of the organic antibacterial agent and the PVC, improve the mechanical property of the antibacterial PVC composite material to a certain extent while ensuring the antibacterial property, and can solve the problems of brittle fracture, color change, yellowing and the like after long-term use.

The technical scheme adopted for solving the technical problems is as follows:

an organic antibacterial agent with a chemical structural formula shown in the specification, wherein R group is-SO ₂NH₂、-COOH、-CH₃、-CH₂CH₃ or phenylbutoxy.

According to the application, the organic antibacterial agent with the chemical structural formula shown in figure 1 is obtained by carrying out grafting reaction on polyhexamethylene monoguanidine and a phenyl compound. The polyhexamethylene guanidine is a high-efficiency broad-spectrum antibacterial agent, has good inhibition and killing effects on various bacteria, viruses and fungi, but has the problems of thermal degradation, oxidative degradation, thermal crosslinking reaction, color change and the like easily occurring in the high-temperature heating processing process, so that the antibacterial effect is reduced, and the end group structure of the polyhexamethylene guanidine is changed by modifying the polyhexamethylene guanidine, so that the antibacterial activity is maintained and the high-temperature resistant effect is realized. As shown in figure 2, figure 2 shows a chemical equation of the synthetic reaction of the organic antibacterial agent, a phenyl compound and polyhexamethylene guanidine are used for grafting reaction, R groups are selected to be-SO ₂NH₂、-COOH、-CH₃、-CH₂CH₃ or phenylbutoxy, the groups are only introduced at the para position of a benzene ring, and the thermal stability of molecules is improved through multiple mechanisms such as conjugation effect, electronic effect, intermolecular interaction or steric hindrance effect, SO that the electronic structure of the antibacterial agent molecules can be stabilized, the intermolecular interaction is increased, and moderate space protection is provided, SO that the structure of the organic antibacterial agent is not easily damaged in the processing process, and the organic antibacterial agent is resistant to high temperature.

In the prior art, substitution is usually carried out at the ortho-para position of the benzene ring, R ₁ is H or COOH, R ₂ is H or NH ₂, and the organic antibacterial agent obtained by adopting the substitution mode has unstable structure during blending processing, is usually characterized by easy decomposition at high temperature, and is destroyed in the benzene ring structure, thereby affecting the thermal stability, mechanical properties and the like of the material. The following causes are considered after the research analysis.

Taking the example that the para position of the benzene ring is substituted by amino (-NH ₂), firstly, the amino group is a strong electron donating group, electrons are provided to the benzene ring through the nitrogen atom, the electron donating effect can increase the electron density of the benzene ring, the benzene ring is easier to react with oxygen at high temperature, the oxidation possibility is improved, and the thermal stability is reduced. On the other hand, the electron donating effect of the amino increases pi electron cloud density of the benzene ring, so that the benzene ring is more active under the heat condition, and is easy to generate decomposition or degradation reaction at high temperature. Secondly, the amino group can form hydrogen bonds with other functional groups containing oxygen atoms in the molecule, which possibly improves the structural stability of the material to a certain extent, however, under the high-temperature condition, the hydrogen bonds are easy to break to cause unstable molecular structure and influence the thermal stability of the material. And at high temperature, the amino group can generate pyrolysis reaction to release ammonia (NH ₃), which can also cause the damage of molecular structure, and the amino group can react with oxygen to generate oxide, so that the probability of thermal oxidation reaction of the antibacterial agent molecules is increased, and the degradation process of the material is further accelerated. Therefore, when the para position of the benzene ring is substituted by amino (-NH ₂) and other groups, the stability of the benzene ring at high temperature is reduced under the combined action of the electron donating effect, hydrogen bond fracture, pyrolysis, oxidation reaction and other factors, so that the overall thermal stability of the material is affected.

The substitution at the ortho position of the benzene ring also has the problems of poor thermal stability modification and even damage to the material structure, taking COOH in the prior art as an example, firstly, carboxyl is a substituent with larger volume, and the substitution at the ortho position can lead to the increase of the steric hindrance of the benzene ring, so that the molecular structure of the benzene ring is distorted or deformed, thereby influencing the stability of the molecule, and the steric hindrance increases the internal stress of the molecule and is easier to thermally degrade at high temperature. Further, at high temperatures the carboxyl groups will pyrolyse to carbon dioxide (CO ₂) and other small molecules, which breaks down the overall structure of the benzene ring, and at high temperatures the carboxyl groups also catalyze acid-catalyzed degradation reactions, leading to further decomposition of the benzene ring. In addition, the acidic character of the carboxyl group can promote the oxidation reaction of the benzene ring and oxygen, so that the material is more easy to undergo oxidation reaction at high temperature. Similarly, ortho carboxyl groups may also form hydrogen bonds with other functional groups on the benzene ring, which intramolecular hydrogen bonds may also break or become unstable at high temperatures. Finally, since the carboxyl group is a strong electron withdrawing group, the conjugated system with the benzene ring can influence the distribution of electron cloud, and although the effect can enhance the stability of the molecule under certain conditions, at high temperature, the strong electron withdrawing effect can also cause the oxidation of the benzene ring or the aggravation of other degradation reactions, thereby influencing the thermal stability. Therefore, when the ortho position of the benzene ring is substituted by carboxyl (-COOH) and other groups, the benzene ring is more easily degraded or structurally changed at high temperature due to the factors of steric hindrance, pyrolysis, acid characteristics, electronic effect and the like, so that the overall thermal stability of the material is reduced.

In the application, the introduction of substituent groups at the ortho position of the benzene ring is avoided, and the negative influence caused by factors such as steric hindrance is avoided. The steric hindrance of ortho substitution is large, which affects the accumulation and arrangement of molecules and leads to an increase of internal stress of the molecules, and becomes a cause of thermal degradation at high temperature. Avoiding the introduction of ortho-substituted groups into the heterogeneous electron distribution and additional electron effects, and reducing the decomposition or rearrangement of the molecule at high temperatures. Further, to better design modify in the para position, the elimination of the introduction of ortho groups also allows para and ortho to not form intramolecular hydrogen bonds (e.g., ortho carboxyl groups may form hydrogen bonds with para sulfonamide), although such intramolecular hydrogen bonds may provide structural stability to some extent, but may also introduce additional internal stress, at high temperatures, the cleavage of the hydrogen bonds may lead to a sudden drop in material thermal stability.

And then, the para position of the benzene ring is independently subjected to substitution modification, the distance between the substituent at the para position and the polymerization main body is far, the steric hindrance is relatively small, the arrangement among the antibacterial agent molecules is relatively regular, the intermolecular accumulation and interaction are more stable, and the thermal stability can be improved. In addition, substitution of the para-position of the benzene ring with groups such as-SO ₂NH₂、-COOH、-CH₃、-CH₂CH₃ or phenylbutoxy generally does not result in strong intramolecular interactions, but the substituent groups can stabilize the benzene ring by conjugation, and this configuration helps to maintain the thermal stability of the molecule. In addition, the substituent groups selected by the application are simpler, and the substituent structure is designed independently at the para position, so that the steric hindrance and the internal stress can be further reduced, the electron distribution is more uniform, and the heat stability is also improved.

In conclusion, the para-position substitution on the benzene ring is adopted, so that the molecular structure is more regular, the steric hindrance is smaller, the electronic effect and the conjugation effect are more uniform, and compared with the para-position and ortho-position simultaneous substitution, the para-position substitution can provide better thermal stability for the organic antibacterial agent molecule, and is suitable for high-temperature blending processing with PVC.

Preferably, the polyhexamethylene guanidine with the polymerization degree of 10-20 has moderate molecular length, can provide enough cationic guanidine groups, simultaneously keeps good solubility and permeability, has good effect in antibacterial application, shows high-efficiency antibacterial activity by destroying cell membranes and interfering the functions of intracellular enzymes and nucleic acid, and has low toxicity and good biocompatibility.

A preparation method of the organic antibacterial agent with the chemical structural formula comprises the following steps of taking polyhexamethylene monoguanidine and phenyl compound as raw materials, carrying out grafting reaction on the phenyl compound and polyhexamethylene monoguanidine with the mass ratio of 0.01-0.1:1 under the protection of nitrogen, stirring for 2-5 h at the reaction temperature of 120-180 ℃ under normal pressure, cooling to 80-100 ℃, preserving heat for 2-5 h, and discharging to obtain the organic antibacterial agent.

The mass ratio, the reaction temperature and the stirring time of the phenyl compound and the polyhexamethylene guanidine are controlled, the reaction is controlled to be thorough, the para-modification effect on the polyhexamethylene guanidine is good, and more target products can be generated. When the phenyl compound is p-carboxybenzenesulfonamide (R= -SO ₂NH₂), the raw material is easy to obtain, and the effect of improving the thermal stability is better.

The preparation method of the antibacterial PVC is characterized by adding the organic antibacterial agent, and comprises the following steps:

S1, mixing, namely uniformly mixing reaction materials at 25-130 ℃ to obtain a first mixed material, wherein the reaction materials comprise, by weight, 90-100 parts of PVC powder, 1-2 parts of plasticizer, 2-5 parts of heat stabilizer and 0.15-0.5 part of organic antibacterial agent.

And S2, banburying, namely conveying the first mixed material to an internal mixer, and banburying for 5-50 min at 130-150 ℃ to obtain a second mixed material.

And S3, plasticating, namely conveying the second mixed material to a plasticator, and plasticating for 5-30 min at 150-180 ℃ to obtain a third mixed material.

And S4, extrusion forming, namely conveying the third mixed material to a filtering extruder, extruding at 120-180 ℃, and calendaring to form a film by a four-roller calender to obtain the antibacterial PVC.

Firstly, uniformly mixing an organic antibacterial agent and PVC powder at 25-130 ℃ by a high-speed mixer to enable the organic antibacterial agent and the PVC powder to be fully contacted, blending the organic antibacterial agent and a PVC matrix to prepare antibacterial PVC, and forming a durable antibacterial barrier under interaction after blending the organic antibacterial agent and the PVC matrix, so that the antibacterial PVC is suitable for long-time use. The organic antibacterial agent can effectively prevent bacteria and other microorganisms from growing and propagating, and a proper amount of heat stabilizer is added, so that the material has good heat stability at the mixing temperature of 25-130 ℃ and does not generate obvious degradation reaction. According to the weight portion, 90-100 portions of PVC powder, 0.15-0.5 portion of organic antibacterial agent, 1-2 portions of plasticizer and 2-5 portions of heat stabilizer are controlled, the reaction materials with the dosage are selected to be favorable for uniformly dispersing the antibacterial agent in a PVC matrix, and the antibacterial agent can be more effectively contacted with bacteria and microorganisms when acting, so that the antibacterial effect is enhanced. The addition of an appropriate amount (0.15-0.5 part) of the organic antibacterial agent ensures antibacterial property, and simultaneously, the problem of overlarge or overlarge viscosity is not easy to cause, even dispersion is easier to realize in the blending process, especially when the use amount of the organic antibacterial agent is less than 0.5 part, agglomeration or precipitation phenomenon can be obviously reduced, uniformity and quality stability of the antibacterial PVC material are ensured, poor material compatibility caused by the excessive molecular weight of the antibacterial agent is effectively avoided, and further phase separation and material mechanical property reduction are avoided.

Secondly, after the antibacterial performance of the floor film material is ensured by the parts of the organic antibacterial agent, the application controls the addition amount of the organic antibacterial agent and the PVC powder to improve the mechanical performance of the antibacterial PVC, and compared with the traditional composite material, the application can avoid the mechanical performance loss of the material in the hot working process. The low-dose organic antibacterial agent is adopted, the low-dose organic antibacterial agent and the PVC matrix are better in compatibility, the mixed materials can be uniformly dispersed during blending, an aggregate is not formed, the mechanical properties (such as tensile strength and impact strength) of PVC powder are not greatly influenced, the organic antibacterial agent can serve as a plasticizer at low concentration, 1-2 parts of plasticizer are matched, the toughness and flexibility of PVC can be effectively improved during blending, the impact strength and ductility of the antibacterial PVC material are improved, and the mechanical properties are maintained or even enhanced. In addition, the film material product itself needs better transparency and appearance retention, a proper amount of plasticizer, heat stabilizer and organic antibacterial agent can well maintain the transparency and appearance of the PVC product, and the processed film material has better mechanical property and is not easy to crack or change color and yellow, which is an important advantage for film materials with higher transparency requirements (such as transparent films or window frames). In summary, in the preparation of the antibacterial PVC formulation, the formulation proportion of the antibacterial PVC is optimized, so that the good antibacterial property of the material can be maintained, the stability in blending processing and the mechanical property of the composite material are improved, the proper amount of antibacterial agent also ensures the processing efficiency and quality uniformity of the material, and the actual requirements are better met.

After raw materials for preparing the antibacterial PVC are mixed to obtain a first mixed material, firstly, the first mixed material is banburying to obtain a second mixed material, the banburying process is a process of converting Plastic (PVC) from solid (powder or granular) to liquid (melt) and to solid (product), and the mixing processing is realized between the organic antibacterial agent and the PVC powder by controlling the process conditions of banburying, so that the common PVC powder is prepared into the composite material with antibacterial property. In the process, the organic antibacterial agent, the PVC powder and other processing aids are subjected to blending processing, the banburying temperature is controlled to be 130-150 ℃, the banburying time is controlled to be 5-50 min, on the basis that the organic antibacterial agent prepared by the method has excellent thermal stability, a better banburying effect can be provided by adopting a higher banburying temperature compared with the traditional technology, the PVC powder and the organic antibacterial agent are fully contacted and compounded, an antibacterial active structure cannot be damaged by high temperature, and antibacterial performance and mechanical performance cannot be influenced.

After banburying, plasticating is carried out on the discharged material of the internal mixer, namely the second mixed material, and the higher temperature of 150-180 ℃ is adopted for plasticating for 5-30 min, so that a third mixed material is obtained, the molecular weight and viscosity of raw rubber in the mixed material can be reduced by plasticating to improve the plasticity of the raw rubber, and proper fluidity is obtained to meet the requirements of further processing such as forming and the like.

After plasticating, extrusion molding is carried out at 120-180 ℃, the third mixed material is melted and flows under the pushing of a screw rod to form a film, and the precipitation phenomenon of the PVC product in and after the production can be reduced by optimizing the extrusion process temperature, so that the mechanical strength and the antibacterial performance of the antibacterial PVC film product are both achieved.

The application method of the antibacterial PVC comprises embossing, cooling, cutting and the like to be used for the floor film.

The antibacterial PVC of the present application can be used for applications including, but not limited to, wallpaper, flooring, furniture surfaces, household appliance surfaces, and the like. Compared with the prior art, the organic antibacterial agent structure and the blending process designed by the application are adopted, a relatively small amount of organic antibacterial agent is added to ensure that the antibacterial PVC has a relatively good antibacterial effect, and has relatively good mechanical strength, as can be seen from fig. 3, the tensile test results of the antibacterial PVC in the embodiments 1,3 and 7 (R= -SO ₂NH₂), wherein 0.15 part, 0.3 part and 0.5 part of antibacterial agent are sequentially added in the three embodiments, and the tensile strength and the elongation at break of the PVC floor film are improved along with the increase of the content of the antibacterial agent, SO that the antibacterial agent disclosed by the application not only can endow the antibacterial effect to the PVC floor film, but also can improve the mechanical property of the floor film, and the reasons are probably that the interfacial compatibility, auxiliary plasticization, nano-structure effect and the like generated after the organic antibacterial agent is blended with the PVC are improved, and the action mechanisms are provided with the toughness and the tensile strength of the composite material are higher on the premise that the toughness and the tensile strength of the composite material are ensured, SO that the PVC floor film has more comprehensive application performance is realized.

Compared with the prior art, the embodiment of the invention has at least the following beneficial effects:

1. the modified polyhexamethylene guanidine organic antibacterial agent with a special R group is designed and synthesized, has good antibacterial performance, and has good thermal stability at high temperature when being blended with PVC, and the antibacterial performance and mechanical performance of the composite material can be simultaneously considered.

2. According to the application, a set of blending processing technology is designed according to the prepared organic antibacterial agent, PVC and the organic antibacterial agent are blended at a higher temperature to prepare the composite PVC material with antibacterial property, and the effective blending between the antibacterial agent and the PVC is ensured by controlling the formula proportion of raw materials, the temperature, the time and other technological parameters, so that the antibacterial structure of the composite material is not damaged, and the comprehensive mechanical property of the composite material is improved.

3. The organic antibacterial agent structure designed by the application is adopted, the prepared antibacterial PVC has better antibacterial effect by adding a small amount of organic antibacterial agent, the raw material cost is reduced, the problems of yellowing, color change and the like are avoided, the quality of the product is better, and the application scene is wide.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following description will briefly explain the embodiments and the drawings used in the comparative examples, it being understood that the following drawings illustrate only some embodiments of the invention and are therefore not to be considered limiting of the scope, and that other related drawings may be obtained from these drawings by those skilled in the art without inventive effort.

FIG. 1 is a chemical structural formula of an organic antibacterial agent of the present invention.

FIG. 2 is a chemical equation of the synthetic reaction of the organic antibacterial agent of the present invention.

Fig. 3 shows the tensile test results of the antibacterial PVC of examples 1,3, and 7 (r= -SO ₂NH₂).

FIG. 4 is a TGA and DTG profile of the organic antimicrobial in example 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other. The present invention will be described in detail with reference to specific examples.

An organic antibacterial agent with a chemical structural formula shown in the specification, wherein R groups in the chemical structural formula are-SO ₂NH₂、-COOH、-CH₃、-CH₂CH₃ or phenylbutoxy, and n=10-20.

The preparation method of the organic antibacterial agent with the structural formula comprises the following steps of taking polyhexamethylene monoguanidine and phenyl compound as raw materials, carrying out grafting reaction on the phenyl compound and polyhexamethylene monoguanidine in a mass ratio of 0.01-0.1:1 under the protection of nitrogen, stirring for 2-5 h at the reaction temperature of 120-180 ℃ under normal pressure, cooling to 80-100 ℃, preserving heat for 2-5 h, and discharging to obtain the organic antibacterial agent. The phenyl compound is preferably p-carboxybenzenesulfonamide.

The preparation method of the antibacterial PVC is characterized by adding the organic antibacterial agent, and comprises the following steps:

S1, mixing, namely uniformly mixing reaction materials at 25-130 ℃ to obtain a first mixed material, wherein the reaction materials comprise, by weight, 90-100 parts of PVC powder, 1-2 parts of plasticizer, 2-5 parts of heat stabilizer and 0.15-0.5 part of organic antibacterial agent.

And S2, banburying, namely conveying the first mixed material to an internal mixer, and banburying for 5-50 min at 130-150 ℃ to obtain a second mixed material.

And S3, plasticating, namely conveying the second mixed material to a plasticator, and plasticating for 5-30 min at 150-180 ℃ to obtain a third mixed material.

And S4, extrusion forming, namely conveying the third mixed material to a filtering extruder, extruding at 120-180 ℃, and calendaring to form a film by a four-roller calender to obtain the antibacterial PVC.

The application method of the antibacterial PVC comprises embossing, cooling, cutting and the like to be used for the floor film.

The invention will be further described with reference to the drawings and examples.

Examples 1 to 8

Examples 1 to 8 of the present invention were all carried out according to the technical scheme in the above specific embodiments, and corresponding antibacterial PVC was prepared respectively, wherein the polymerization degree of polyhexamethylene monoguanidine (PHMG) used was n=10 to 20, and it is understood that PHMG exists in the form of a mixture, and other implementation cases are shown in tables 1 to 2.

Table 1 formulation ratios of organic antibacterial agents in examples 1 to 8

Examples	R group	Mass ratio of phenyl compound to PHMG	Grafting reaction temperature, time
				Example 1	-SO2NH2	0.01:1	120°C、2h
Example 2	-SO2NH2	0.025:1	140°C、3h
				Example 3	-SO2NH2	0.075:1	170°C、4.5h
Example 4	-SO2NH2	0.1:1	180°C、5h
				Example 5	Benzene butoxy	0.01:1	120°C、2h
Example 6	Benzene butoxy	0.1:1	180°C、5h
				Example 7	-COOH	0.01∶1	120°C、2h
Example 8	-COOH	0.1∶1	180°C、5h

Table 2 formulation and preparation process conditions of antibacterial PVC in examples 1 to 8

Comparative examples 1 to 3

The non-end-capped PHMG antibacterial agent, namely the non-modified polyhexamethylene guanidine antibacterial agent, is adopted in comparative examples 1-3, and the mass concentrations are 0.15%, 0.3% and 0.5% in sequence, so that the corresponding antibacterial PVC is prepared respectively.

Comparative examples 4 to 6

The inorganic antibacterial agent nano silver is adopted in comparative examples 4-6, and the mass concentrations are 0.15%, 0.3% and 0.5% in sequence, so that the corresponding antibacterial PVC is prepared respectively.

Comparative examples 7 to 8

In comparative example 8, the inorganic antibacterial agent is adopted in a nano oxidation state, and the mass concentration is 0.3% and 0.5% in sequence, so that the corresponding antibacterial PVC is prepared respectively.

Experimental example

The antibacterial PVC obtained in the example and the comparative example are subjected to antibacterial tests of the floor film, the test mode refers to the evaluation part 2 of the textile-antibacterial performance of the standard GB/T20944.2, wherein 100 mu L of bacterial solutions with different bacterial concentrations (the dilution factor of the original bacterial solution is 10 ³～10⁷) and different mass PVC films (0.1-20 mg) are absorbed and co-cultured for one night (12 h), 100 mu L of the co-cultured bacterial solutions are taken out for plating, and the observation result is carried out for 24 h. The test results are shown in fig. 3 to 4 and tables 3 to 4, and table 3 is the test results of the antibacterial performance and mechanical performance of the antibacterial PVC in examples and comparative examples. As can be seen from Table 3, according to the evaluation of the textile-antibacterial properties of Standard GB/T20944.2 part 2, when the addition amount of the organic antibacterial agent of the example of the present application is 0.3 parts, the killing rate of the floor film against Escherichia coli and Staphylococcus aureus respectively reaches 99.8% and 100%, which proves the excellent antibacterial ability of the floor film on the one hand, and the organic antibacterial agent used on the other hand has the characteristic of high temperature processing resistance. And in comparative examples 1-8, three antibacterial agents, namely an unmodified PHMG antibacterial agent, a nano silver antibacterial agent and a nano titanium dioxide antibacterial agent, are respectively adopted, and are decomposed and denatured to different degrees under the same processing conditions, so that the antibacterial agent cannot be blended with PVC at high temperature, and the antibacterial performance is lost.

FIG. 3 shows the tensile test results of the antibacterial PVC films of examples 1, 3 and 7 with different organic antibacterial agent contents. As can be seen from Table 3 and FIG. 3, with the increase of the content of the added organic antibacterial agent, the tensile strength and the elongation at break of the PVC floor film are both improved, which indicates that the organic antibacterial agent prepared by the application not only can endow the PVC floor film with antibacterial effect, but also can improve the mechanical property of the floor film.

Fig. 4 is a TGA and DTG curve of the organic antibacterial agent of example 1, and it can be seen from fig. 4 that the organic antibacterial agent prepared according to the present application starts to decompose at about 200 ℃ and reaches a maximum decomposition temperature at about 395 ℃ and exhibits excellent thermal stability.

Table 3 results of antibacterial properties and mechanical properties test of antibacterial PVC in examples and comparative examples

Table 4 shows the results of the light transmittance and chromaticity color difference tests of the antibacterial PVC in examples 1,3, and 7 and comparative examples 1,2, and 3. As can be seen from Table 4, the addition of the organic antibacterial agent in the present application has little effect on the light transmittance, color difference and chromaticity of the antibacterial PVC film, while when other antibacterial agents are added, as in comparative example 1, the antibacterial PVC film is severely yellowing, the light transmittance is greatly reduced, and the color difference is great as compared with the ordinary PVC sample, which reaches 91.99. And with the increase of the content of the corresponding antibacterial agent, as in comparative example 3, the yellowing of the antibacterial PVC film is more serious, the color difference can reach 94.82, which fully shows that the organic antibacterial agent can effectively resist the high temperature in the processing process of the antibacterial PVC film, and the mechanical property is improved.

Table 4 light transmittance and color difference test results of antibacterial PVC film

The embodiments described above are some, but not all embodiments of the application. The detailed description of the embodiments of the application is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Claims (6)

1. An organic antibacterial agent is characterized by having a chemical structural formula as follows, wherein R groups in the chemical structural formula are as follows:

-SO ₂NH₂、-COOH、-CH₃、-CH₂CH₃ or phenylbutoxy.

2. The organic antibacterial agent according to claim 1, wherein n=10 to 20 in the chemical structural formula.

3. The method for preparing the organic antibacterial agent according to claim 1, which is characterized by comprising the following steps of carrying out grafting reaction on polyhexamethylene monoguanidine and phenyl compound under the protection of nitrogen, wherein the mass ratio of the phenyl compound to the polyhexamethylene monoguanidine is 0.01-0.1:1, the reaction temperature is 120-180 ℃, stirring for 2-5 h under normal pressure, cooling to 80-100 ℃, preserving heat for 2-5 h, and discharging to obtain the organic antibacterial agent.

4. A method for preparing an organic antibacterial agent according to claim 3, wherein the phenyl compound is p-carboxybenzenesulfonamide.

5. A preparation method of antibacterial PVC is characterized in that, the organic antibacterial agent according to claim 1, which comprises the following steps:

S1, uniformly mixing reaction materials at 25-130 ℃ to obtain a first mixed material, wherein the reaction materials comprise, by weight, 90-100 parts of PVC powder, 1-2 parts of plasticizer, 2-5 parts of heat stabilizer and 0.15-0.5 part of organic antibacterial agent;

S2, banburying, namely conveying the first mixed material to an internal mixer, and banburying for 5-50 minutes at 130-150 ℃ to obtain a second mixed material;

s3, plasticating, namely conveying the second mixed material to a plasticator, and plasticating for 5-30 minutes at 150-180 ℃ to obtain a third mixed material;

and S4, extrusion forming, namely conveying the third mixed material to a filtering extruder, extruding at 120-180 ℃, and calendaring to form a film by a four-roller calender to obtain the antibacterial PVC.

6. A method of using the antibacterial PVC according to claim 5, wherein the antibacterial PVC is used for a floor film.