CN111944156B

CN111944156B - Antibacterial agent and preparation method and application thereof

Info

Publication number: CN111944156B
Application number: CN201910413818.9A
Authority: CN
Inventors: 初立秋; 张师军; 李�杰; 刘建叶; 徐萌; 权慧; 张琦; 董穆; 白弈青; 陈若石
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Priority date: 2019-05-17
Filing date: 2019-05-17
Publication date: 2022-07-12
Anticipated expiration: 2039-05-17
Also published as: CN111944156A

Abstract

The invention relates to an antibacterial agent and a preparation method and application thereof in the field of antibacterial materials. The surface of the antibacterial agent is grafted with a guanidine salt polymer; the antibacterial agent is a cross-linked copolymer containing a structural unit A, a structural unit B and a structural unit C; the structural unit A is provided by maleic anhydride; the structural unit B is provided for a monomer M; the structural unit C provides a cross-linking agent; wherein the monomer M is selected from styrene and/or alpha-methyl styrene; the cross-linking agent can be a free radical polymerizable vinyl-containing monomer with more than two functionalities; the antibacterial agent is in the form of microspheres or spheroidal; the average particle size of the antibacterial agent is 150-2000 nm. The antibacterial agent has the advantages of regular appearance, spherical or quasi-spherical shape, good fluidity and the like, and can be directly added into plastics, rubber and fibers for use.

Description

Antibacterial agent and preparation method and application thereof

Technical Field

The invention relates to the field of antibacterial materials, and in particular relates to an antibacterial agent and a preparation method and application thereof.

Background

In recent years, with the improvement of the living standard of people and the enhancement of the health consciousness, the demand for various antibacterial material products, in which the antibacterial plastic products account for a large proportion, has been increasing, and various living products, including refrigerators, air conditioners, various food containers, packaging bags, washing machines, toy products, dust collectors, and the like, all use various thermoplastic antibacterial plastics. The preparation of the antibacterial plastic is mainly realized by adding a certain amount of antibacterial agent in the granulation process of the antibacterial plastic. The antibacterial agents are of various types, and mainly include inorganic antibacterial agents and organic antibacterial agents.

The guanidine salt polymer is an antibacterial polymer with a guanidyl group in a molecular structure, is a novel broad-spectrum, efficient, nontoxic and nonirritating antibacterial product developed in the nineties of the last century, and is widely applied to the fields of textile, agriculture, food, sanitation and the like. Currently, the variety of guanidine salt polymers mainly includes polyhexamethylene (bis) guanidine hydrochloride, polyhexamethylene (bis) guanidine propionate, polyhexamethylene (bis) guanidine stearate, and other inorganic or organic salts of polyhexamethylene (bis) guanidine, polyoxyethylene guanidine, and the like.

Guanidine salt polymers are mostly used in the form of aqueous solutions because of their excellent solubility in water, and are used as bactericides for water treatment in japanese patent publication No. JP05209195A, US patent publication No. US4891423A, and chinese patent publication No. CN 101156586A. Besides, the guanidine salt polymer also has good thermal stability, the thermal decomposition temperature is higher and can reach 280 ℃, so that the guanidine salt polymer can be used as an additive to be applied to plastic, fiber and rubber products to obtain an antibacterial product. However, most guanidinium polymers are very water soluble, making powder samples difficult, limiting their use in plastic, rubber, and fiber applications. Chinese patent publication No. CN101037503A discloses a method for preparing a powdered guanidine salt polymer product, which separates a guanidine salt polymer from an aqueous solution through an ion separation exchange membrane to prepare a powder sample; however, the method for preparing the guanidine salt polymer powder has the disadvantages of harsh conditions and complicated process.

The Chinese patent with publication number CN1350022A discloses a method for preparing polyamine and guanidinium polymer, wherein the guanidinium polymer contains double bonds, epoxy and other active groups in the molecular structure, and is used for carrying out melting, solution and solid phase grafting reaction with resin polymer to prepare an antibacterial plastic product; but the procedure is cumbersome. The composite antibacterial agent is prepared by using a coprecipitation method of a guanidinium polymer and pyridine sulfate, silicate and the like under the publication numbers of CN102453315A and CN102453316A, and is applied to film products such as polylactic acid, polypropylene and the like and foam plastic products; however, sodium pyrithione is used, which is costly. Chinese patent publication No. CN102453273A provides an antibacterial masterbatch based on guanidinium polymer, which needs to be operated at a certain temperature during the preparation of an antibacterial agent, and has high energy consumption, and the morphology and particle size of the dried and pulverized product are not well controlled.

Disclosure of Invention

In order to solve the problems existing in the prior art that the guanidine salt polymer antibacterial agent exists in the application process of antibacterial plastics, the invention provides an antibacterial agent. In particular to an antibacterial agent and a preparation method and application thereof. The obtained antibacterial agent has the characteristics of good fluidity and good water resistance, and can be continuously produced in large batches.

One of the purposes of the invention is to provide an antibacterial agent, wherein the antibacterial agent is a crosslinked copolymer microsphere with a guanidine salt polymer grafted on the surface, and the crosslinked copolymer is a crosslinked copolymer containing a structural unit A, a structural unit B and a structural unit C; the antibacterial agent is internally provided with a cross-linked structure polymer, and the surface of the antibacterial agent is provided with a grafted guanidine salt polymer;

the antibacterial agent is in the form of microspheres and/or quasi-spheres; the average particle size of the antibacterial agent is 150-2000nm, preferably 250-1500 nm, and more preferably 800-1300 nm.

Wherein the molar ratio of structural unit A to structural unit B is in the range of 0.5: 1-1: 0.5, preferably 0.75: 1-1: 0.75. the structural units of the present application can be characterized by infrared and nuclear magnetic tests.

The crosslinking degree of the antibacterial agent is more than or equal to 65%, preferably 75-100%, and more preferably 85-100%.

The weight percentage of the dissolution of the antibacterial agent in 5 times of acetone at 50 ℃ for 30min is less than or equal to 10 wt%;

the structural unit A is provided by maleic anhydride, the structural unit B is provided by a monomer M, and the structural unit C is provided by a cross-linking agent; wherein the monomer M is selected from styrene and/or alpha-methyl styrene; the cross-linking agent is selected from vinyl-containing monomers with more than two functionalities and capable of free radical polymerization;

the structure of the monomer M is shown as the formula X:

in the formula X, R is H or methyl;

the crosslinking agent may be any of various conventional vinyl-containing monomers having two or more functionalities and capable of radical polymerization. Preferably, the crosslinking agent can be at least one of divinylbenzene and an acrylate crosslinking agent containing at least two acrylate groups; the acrylate group is preferably of the formula: -O-C (O) -C (R') ═ CH₂Wherein R' is H or C1-C4 alkyl (such as methyl).

More preferably, the crosslinking agent may be selected from at least one of divinylbenzene, propylene glycol-based di (meth) acrylate, ethylene glycol-based di (meth) acrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane tetraacrylate, trimethylolpropane tetramethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, phthalic acid ethylene glycol diacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and ethoxylated multifunctional acrylate; the above-mentioned propylene glycol-based bis (meth) acrylate refers to propylene glycol-based bisacrylate, propylene glycol-based bismethacrylate; the above-mentioned ethylene glycol bis (meth) acrylate refers to ethylene glycol bisacrylate and ethylene glycol bismethacrylate.

Among them, the propylene glycol-based bis (meth) acrylate is preferably at least one selected from the group consisting of 1, 3-propanediol dimethacrylate, 1, 2-propanediol dimethacrylate, 1, 3-propanediol diacrylate and 1, 2-propanediol diacrylate; the ethylene glycol-based di (meth) acrylate is preferably at least one selected from the group consisting of ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, tetraethylene glycol dimethacrylate and tetraethylene glycol diacrylate.

The guanidine salt polymer is at least one or a mixture of several selected from polyhexamethylene (double) guanidine inorganic salt, polyhexamethylene (double) guanidine organic salt, polyoxyethylene guanidine inorganic salt and polyoxyethylene guanidine organic salt.

The guanidine salt polymer can be specifically selected from at least one of polyhexamethylene (bis) guanidine hydrochloride, polyhexamethylene (bis) guanidine phosphate, polyhexamethylene (bis) guanidine sulfonate, polyhexamethylene (bis) guanidine acetate, polyhexamethylene (bis) guanidine propionate, polyhexamethylene (bis) guanidine stearate, polyhexamethylene (bis) guanidine laurate, polyhexamethylene (bis) guanidine benzoate, polyoxyethylene guanidine hydrochloride, polyoxyethylene guanidine phosphate, polyoxyethylene guanidine sulfonate, polyoxyethylene guanidine acetate, polyoxyethylene guanidine propionate, polyoxyethylene guanidine stearate, polyoxyethylene guanidine laurate, and polyoxyethylene guanidine benzoate; at least one of polyhexamethylene (bis) guanidine hydrochloride, polyhexamethylene (bis) guanidine propionate, and polyoxyethylene guanidine hydrochloride is preferable. The polyhexamethylene (bis) guanidine hydrochloride mentioned above refers to polyhexamethylene guanidine hydrochloride, polyhexamethylene biguanide hydrochloride, and the like.

The weight percentage of the antibacterial agent dissolved in 5 times of acetone (50 ℃, 30min) is less than or equal to 10 wt% (such as 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5.5 wt%, 6.5 wt%, 7.5 wt%, 8.5 wt%, 10 wt% or any value between the above values).

The crosslinking degree of the antibacterial agent is more than or equal to 65% (such as 65%, 70%, 75%, 80%, 85%, 90% or any value between the values).

The antibacterial agent is microsphere or sphere-like, and has an average particle size of 150-2000nm (such as 150nm, 250nm, 350nm, 450nm, 550nm, 650nm, 750nm, 850nm, 950nm, 1050nm, 1150nm, 1250nm, 1350nm, 1450nm, 1550nm, 1650nm, 1750nm, 1850nm, 2000nm or any value between the values). The antibacterial agent has a shell cross-linked structure, so that the antibacterial agent has better solvent resistance and thermal stability.

The degree of crosslinking of the antimicrobial agent is indicative of the gel content, as measured by a solvent extraction method. The average particle size is characterized by a number average particle size and is determined by means of a scanning electron microscope.

The other object of the invention is to provide the preparation method of the antibacterial agent, which comprises the steps of reacting the components including the maleic anhydride, the monomer M and the cross-linking agent, and then reacting the reaction product with the guanidine salt polymer to obtain the antibacterial agent.

The method specifically comprises the following steps:

(1) in an organic solvent, in the presence of a first part of initiator, contacting the maleic anhydride with a first part of monomer M for reaction, and introducing a solution containing the crosslinking agent for continuous reaction to obtain a suspension product;

wherein the crosslinker-containing solution comprises the crosslinker, a second portion of the monomer M, and a second portion of the initiator;

(2) and (2) adding a guanidine salt polymer solution into the suspension product obtained in the step (1) to continue reacting, grafting a guanidine salt polymer on the surface of the product obtained in the step (1), and separating and washing after the reaction is finished to obtain the antibacterial agent.

Wherein,

the total amount of the first part of monomer M and the second part of monomer M can be 50 to 150mol, preferably 75 to 100mol, relative to 100mol of maleic anhydride.

In the step (1), the monomer M may be fed in one step (i.e., the amount of the second portion of the monomer M may be zero), or may be fed in two portions (i.e., the first portion of the monomer M and the second portion of the monomer M). According to a preferred embodiment of the present invention, the molar ratio between the second portion of monomers M and the first portion of monomers M may be (0-100): 100 (e.g., 0, 1:100, 5:100, 15:100, 25:100, 30:100, 45:100, 50:100, 60:100, 70:100, 80:100, 90:100, 100:100 or any value between the above values).

In the preparation method of the antibacterial agent, the amount of the organic solvent can be selected conventionally as long as a medium is provided for the reaction in the step (1), and preferably, the amount of the organic solvent can be 50-150L relative to 100mol of maleic anhydride.

The organic solvent and the solvent of the cross-linking agent solution can be the same or different and can be selected from at least one of organic acid alkyl ester, a mixture of the organic acid alkyl ester and alkane, and a mixture of the organic acid alkyl ester and aromatic hydrocarbon;

wherein the organic acid alkyl ester may include, but is not limited to, at least one selected from the group consisting of methyl formate, ethyl formate, methyl propyl ester, methyl butyl ester, methyl isobutyl ester, pentyl formate, methyl acetate, ethyl ester, propylene acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, pentyl acetate, isoamyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, isobutyl butyrate, isoamyl isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate, and ethyl phenylacetate;

the alkane can be selected from n-hexane and/or n-heptane;

the aromatic hydrocarbon may include, but is not limited to, at least one selected from the group consisting of benzene, toluene, and xylene.

In the step (1), the step (c),

in the preparation method of the antibacterial agent, the total usage amount of the first part initiator and the second part initiator is 0.05-10 mol, and more preferably 0.8-1.5 mol, relative to 100mol of maleic anhydride.

Preferably, the amount of the crosslinking agent is 1 to 40mol, more preferably 10 to 20mol, relative to 100mol of maleic anhydride.

In the step (1), the initiator may be fed in one step (i.e. the amount of the second part of initiator may be zero), or may be fed in two parts (i.e. the first part of initiator and the second part of initiator). According to a more preferred embodiment of the present invention, the molar ratio between the second portion of initiator and the first portion of initiator may be (0-100): 100 (e.g. 0, 1:100, 5:100, 15:100, 25:100, 30:100, 45:100, 50:100, 60:100, 70:100, 80:100, 90:100, 100:100 or any value in between).

The initiator may be a reagent commonly used in the art for initiating polymerization of maleic anhydride and alpha-methylstyrene (or styrene), and may be a thermal decomposition type initiator. Preferably, the initiator may be selected from at least one of dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, lauroyl peroxide, t-butyl peroxybenzoate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, azobisisobutyronitrile, and azobisisoheptonitrile.

In the step (1), the maleic anhydride is contacted with the monomer M to react, namely the maleic anhydride and the monomer M are not completely reacted, and only part of the maleic anhydride and the monomer M are subjected to polymerization reaction in the presence of an initiator. The conditions for contacting maleic anhydride with the monomer M to carry out the reaction may be conventional conditions as long as the maleic anhydride and the monomer M are controlled to carry out only partial polymerization reaction, and preferably, the conditions for contacting maleic anhydride with the first part of the monomer M to carry out the reaction include: the reaction is carried out in an inert atmosphere, the reaction temperature is 50-90 ℃ (preferably 60-70 ℃), and the reaction time is 0.5-4 h (preferably 0.5-2 h).

In the step (1), after the maleic anhydride is contacted with the first part of the monomer M to perform partial reaction, a solution containing a cross-linking agent is introduced to continue the reaction, so that a shell cross-linked structure is particularly formed. The conditions for continuing the reaction may be conventional conditions as long as each substrate is allowed to participate in the reaction as much as possible, and preferably, the conditions for continuing the reaction include: the reaction temperature is 50-90 ℃ (preferably 60-70 ℃), and the reaction time is 2-15 h. According to a more preferred embodiment of the invention, the introduction of the solution containing the crosslinking agent continues the reaction in such a way that: and (3) dropwise adding the solution containing the cross-linking agent into the product obtained in the step (1) within 1-3 h at 50-90 ℃ (preferably 60-70 ℃), and continuing to perform heat preservation reaction for 1-4 h.

In the method for preparing the antibacterial agent, there is no particular requirement on the type and content of the solvent in the solution containing the crosslinking agent, as long as the solute therein is sufficiently dissolved, and generally, the type of the solvent in the solution containing the crosslinking agent may be selected to be the same as that of the organic solvent (i.e., including the organic acid alkyl ester as described above), and the content of the crosslinking agent in the solution containing the crosslinking agent may be 0.5 to 3 mol/L.

In the step (2), the step (c),

the guanidine salt polymer solution is a guanidine salt polymer aqueous solution;

adding a guanidine salt polymer aqueous solution into the product obtained in the step (1) to carry out reaction. The amount of the guanidine salt polymer aqueous solution is 500 to 10000g, preferably 1000 to 8000g, and more preferably 1000 to 5000g, relative to 1000g of maleic anhydride. The concentration of the guanidine salt polymer aqueous solution is 0.5-50 wt%, preferably 1-30 wt%, more preferably 1-20 wt%.

In the step (2), the grafting reaction may be performed under conventional conditions, for example, the conditions of the grafting reaction include: the reaction temperature is 0-100 ℃, preferably 2.5-90 ℃, and more preferably 5-80 ℃; the reaction time is 0.5-10 h, preferably 0.5-8 h, and more preferably 0.5-6 h. The reaction is preferably carried out under rapid stirring at a speed of 50 to 1000rpm, preferably 50 to 500rpm, more preferably 100 to 500 rpm.

In the step (2), the product (suspension) obtained in the step (1) may be subjected to post-treatment (separation, washing and drying) and then subjected to grafting reaction. The washing may employ a conventional washing solvent, for example, at least one of n-hexane, isohexane, cyclohexane, n-heptane, n-octane, isooctane, methanol, ethanol, propanol, isopropanol, diethyl ether, isopropyl ether, and methyl tert-butyl ether. And directly adding the dried product into a guanidinium polymer aqueous solution for reaction, wherein the concentration of the guanidinium polymer aqueous solution is 0.5-50 wt%, preferably 1-30 wt%, and more preferably 1-20 wt%.

The final product obtained in step (2) may be further separated to obtain an antibacterial product, for example, the separation is performed in the following manner: centrifuging, washing with water, washing with an organic solvent (the washing solvent as described above, i.e., at least one of n-hexane, isohexane, cyclohexane, n-heptane, n-octane, isooctane, methanol, ethanol, propanol, isopropanol, diethyl ether, isopropyl ether, and methyl tert-butyl ether can be used), centrifuging, and drying (e.g., vacuum drying).

The reactor or reaction equipment in step (1) and step (2) of the preparation method of the invention is a reactor or reaction equipment which is common in the prior art.

The invention also provides the application of the antibacterial agent or the antibacterial agent prepared by the preparation method in preparing antibacterial polymers and products thereof.

The inventors of the present invention found in their research that the antibacterial agent product of the present invention can be effectively obtained by directly subjecting the suspension obtained in step (1) and the aqueous solution of the guanidinium polymer to a graft reaction without performing a step of removing the organic solvent. Therefore, according to a preferred embodiment of the present invention, in the step (2) of the present invention, the product obtained in the step (1) may be directly reacted with the guanidine salt polymer aqueous solution (one-pot method), so that a mixed system containing the antibacterial agent is obtained, and the mixed system may be further subjected to a separation treatment to obtain the antibacterial agent product, for example, in the following manner: standing for layering, recycling the organic phase, centrifuging the heavy phase, washing with water, centrifuging, and drying (such as vacuum drying) to obtain the antibacterial agent. The optimized method adopts a one-pot process, and the product post-treatment only needs one-time liquid-liquid separation, solid-liquid separation, washing and drying, so that the time consumption of a single batch is effectively shortened, the process flow is simplified, unit equipment is reduced, and the energy consumption is effectively reduced; the process only needs one organic solvent as a reaction medium, the solvent can be recycled only through layering and drying operations, a special water distribution device is not needed, layering can be achieved in the reactor, the solvent can be recycled without distillation and purification, energy is saved, consumption is reduced, and pollution of the organic solvent to the environment can be effectively reduced.

The antibacterial agent has the advantages of regular appearance, spherical or quasi-spherical shape, good fluidity and the like, and can be directly added into plastics, rubber and fibers for use.

Detailed Description

The present invention will be further described with reference to the following examples. However, the present invention is not limited to these examples. Source of raw materials

Polyhexamethyleneguanidine hydrochloride, Shanghai high polymer industries, Inc.;

polyhexamethylene guanidine propionate, Shanghai high Polymer industries, Inc.;

polyhexamethylene biguanide hydrochloride, industrial ltd, shanghai;

polypropylene, No. 7726, yanshan petrochemical;

compound antioxidant: mixing antioxidant 1010 (Basff), antioxidant 168 (Basff), and calcium stearate (Shandong Haonan) at a mass ratio of 2/2/1.

Antibacterial detection standard and operation steps:

1. antibacterial test standard: GB/T31402-2015 plastic surface antibacterial performance test method, detection bacteria: escherichia coli (Escherichia coli) ATCC 25922, Staphylococcus aureus (Staphylococcus aureus) ATCC 6538.

2. An antibacterial testing step, which refers to an antibacterial plastic detection standard GB/T31402-2015 for testing, and comprises the following specific steps: and (3) sterilizing a sample to be detected by using 75% ethanol, drying the sample, and diluting the strain into a bacterial suspension with a proper concentration by using sterile water for later use. 0.2mL of the bacterial suspension was dropped on the surface of the sample, and a polyethylene film (4.0 cm. times.4.0 cm) having a thickness of 0.1mm was coated thereon to form a uniform liquid film of the bacterial suspension between the sample and the film. Culturing at 37 ℃ for 18-24 hours with the relative humidity of 90%. The bacterial liquid is washed by sterile water, diluted to a proper concentration gradient, and 0.1mL of the diluted bacterial liquid is uniformly coated on a prepared sterile agar culture medium. The culture was carried out at 37 ℃ for 18 to 24 hours, and the results were observed. The negative control was replaced with a sterile plate and the other operations were identical.

3. The degree of crosslinking of the antimicrobial agent is expressed in terms of gel content and is measured by a solvent extraction methodAnd (5) obtaining the product. The specific method comprises the following steps: weighing W of a sample to be measured₁Then placing the sample to be tested in acetone with the weight 5 times of that of the sample, extracting the sample at 50 ℃ for 30min, and then measuring, drying and weighing W after the extraction is finished₂A degree of crosslinking of W₂/W₁X 100%. The content of soluble substances is (1-W)₂/W₁)×100％。

1. Preparation of antibacterial agents

Example 1:

(1) dissolving 1000g of maleic anhydride, 1180g of alpha-methylstyrene and 20g of azobisisobutyronitrile into 8L of isoamyl acetate, and reacting for 1 hour at 70 ℃ in a nitrogen atmosphere;

(2) 260g of divinylbenzene is dissolved in 2L of isoamyl acetate to form a second solution, the second solution is dropwise added into the reaction system in the step (1) for 2 hours, and after the dropwise addition is finished, the reaction system is continuously subjected to heat preservation reaction for 3 hours;

(3) after the reaction, 3500g (15 wt%) of an aqueous solution of polyhexamethylene biguanide hydrochloride was added and the reaction was carried out at 80 ℃ for 3 hours. And standing and layering the reacted system, centrifuging and separating the heavy phase for 20 minutes by a centrifuge under the condition of 5000rad/min, adding 4L of water into the solid, stirring and washing the solid, centrifuging and separating for 20 minutes by the centrifuge under the condition of 5000rad/min, and drying the solid in vacuum to obtain the antibacterial agent with the guanidinium polymer grafted on the surface #1. The obtained antibacterial agent had an average particle diameter of 1050 nm. The weight percentage of the obtained antibacterial agent dissolved out in 5 times of acetone at 50 ℃ for 30min is 6.5%.

Example 2:

the antibacterial agent was prepared according to the method of example 1, except that the system reacted in step (2) was centrifuged for 30 minutes at 5000rad/min by a centrifuge to obtain crosslinked α -methylstyrene/maleic anhydride polymer microspheres, which were washed with n-hexane for purification and dried under vacuum. Then, the dried microspheres of crosslinked α -methylstyrene/maleic anhydride polymer were added to 3500g (15 wt%) of an aqueous solution of polyhexamethylene biguanide hydrochloride and reacted at 80 ℃ for 3 hours. And centrifuging the reacted system for 20 minutes by a centrifuge under the condition of 5000rad/min, adding 4L of water into the solid, stirring and washing the solid, centrifuging the solid for 20 minutes by the centrifuge under the condition of 5000rad/min, and drying the solid in vacuum to obtain the antibacterial agent with the guanidinium polymer grafted on the surface # 2. The average particle diameter of the obtained antibacterial agent was 1080 nm. The weight percentage of the obtained antibacterial agent dissolved out in 5 times of acetone at 50 ℃ for 30min is 6.2%.

Example 3:

(1) dissolving 1000g of maleic anhydride, 1020g of alpha-methylstyrene and 15g of azobisisobutyronitrile into 8L of isoamyl acetate, and reacting at 70 ℃ for 0.5 hour under the atmosphere of nitrogen;

(2) 260g of divinylbenzene and 5g of azobisisobutyronitrile are dissolved in 2L of isoamyl acetate to form a second solution, the second solution is dropwise added into the reaction system in the step (1) for 2 hours, and after the dropwise addition is finished, the reaction system is continuously subjected to heat preservation reaction for 4 hours;

(3) after the reaction, 5000g (5 wt%) of an aqueous solution of polyhexamethyleneguanidine hydrochloride was added and the reaction was carried out at 60 ℃ for 7 hours. And standing and layering the reacted system, centrifuging and separating the heavy phase for 20 minutes by a centrifuge under the condition of 5000rad/min, adding 4L of water into the solid, stirring and washing the solid, centrifuging and separating for 20 minutes by the centrifuge under the condition of 5000rad/min, and drying the solid in vacuum to obtain the antibacterial agent with the guanidinium polymer grafted on the surface # 3. The average particle size of the obtained antibacterial agent was 990 nm. The weight percentage of the obtained antibacterial agent dissolved out in 5 times of acetone at 50 ℃ for 30min is 5.5%.

Example 4:

(1) dissolving 1000g of maleic anhydride, 910g of alpha-methylstyrene and 20g of azobisisobutyronitrile into 7L of isoamyl acetate, and reacting for 1 hour at 70 ℃ under the atmosphere of nitrogen;

(2) dissolving 200g of alpha-methyl styrene and 260g of divinylbenzene in 3L of isoamyl acetate to obtain a second solution, dropwise adding the second solution into the reaction system obtained in the step (1) for 3 hours, and after dropwise adding is finished, keeping the temperature of the reaction system for reaction for 3 hours;

(3) after the reaction, 500g (25 wt%) of an aqueous solution of polyhexamethylene guanidine propionate was added and the reaction was carried out at 10 ℃ for 10 hours. And standing the reacted system for layering, centrifuging the heavy phase for 20 minutes under the condition of 5000rad/min by a centrifuge, adding 4L of water into the solid, stirring and washing the solid, centrifuging for 20 minutes under the condition of 5000rad/min by the centrifuge, and drying the solid in vacuum to obtain the antibacterial agent with the guanidinium polymer grafted on the surface # 4. The average particle diameter of the obtained antibacterial agent was 1010 nm. The weight percentage of the obtained antibacterial agent dissolved out in 5 times of acetone at 50 ℃ for 30min is 5.8%.

Example 5:

(1) dissolving 1000g of maleic anhydride, 680g of alpha-methyl styrene and 20g of azobisisobutyronitrile into 7L of isoamyl acetate, and reacting at 80 ℃ for 0.5 hour under the atmosphere of nitrogen;

(2) 380g of divinylbenzene is dissolved in 1L of isoamyl acetate to form a second solution, the second solution is dropwise added into the reaction system in the step (1) for 2 hours, and after the dropwise addition is finished, the reaction system is continuously subjected to heat preservation reaction for 3 hours; and centrifuging the reacted system for 30 minutes by a centrifuge under the condition of 5000rad/min to obtain the crosslinked alpha-methylstyrene/maleic anhydride polymer microspheres, washing and purifying by normal hexane, and drying in vacuum.

(3) 200g of polyhexamethylene biguanide hydrochloride solid powder is dissolved in 4000g of water, 1000g of crosslinked alpha-methylstyrene/maleic anhydride polymer microspheres are added to the polyhexamethylene biguanide hydrochloride aqueous solution, and reacted at 50 ℃ for 3 hours. And centrifuging the reacted system for 20 minutes by a centrifuge under the condition of 5000rad/min, adding 4L of water into the solid, stirring and washing the solid, centrifuging the solid for 20 minutes by the centrifuge under the condition of 5000rad/min, and drying the solid in vacuum to obtain the antibacterial agent with the guanidinium polymer grafted on the surface # 5. The average particle diameter of the obtained antibacterial agent was 1150 nm. The weight percentage of the obtained antibacterial agent dissolved out in 5 times of acetone at 50 ℃ for 30min is 3.8%.

Example 6:

an antibacterial agent was prepared by following the procedure of example 5, except that the amount of divinylbenzene in the step (2) was changed to 500g, to finally obtain antibacterial agent # 6. The obtained antibacterial agent had an average particle diameter of 1180 nm. The weight percentage of the obtained antibacterial agent dissolved out in 5 times of acetone at 50 ℃ for 30min is 2.6%.

Example 7:

(3) after the reaction, 2500g (10 wt%) of an aqueous solution of polyhexamethylene biguanide hydrochloride was added and the reaction was carried out at 20 ℃ for 10 hours. And standing and layering the reacted system, centrifuging and separating the heavy phase for 20 minutes by a centrifuge at 5000rad/min, adding 4L of water into the solid, stirring and washing the solid, centrifuging and separating for 20 minutes by the centrifuge at 5000rad/min, and drying the solid in vacuum to obtain the antibacterial agent 7# with the guanidinium polymer grafted on the surface. The obtained antibacterial agent had an average particle diameter of 1030 nm. The weight percentage of the obtained antibacterial agent dissolved out in 5 times of acetone at 50 ℃ for 30min was 6.2%.

Example 8:

an antibacterial agent was prepared by following the procedure of example 1 except that α -methylstyrene in step (1) was changed to 1040g of styrene to finally obtain antibacterial agent # 8. The average particle diameter of the obtained antibacterial agent was 950 nm. The weight percentage of the obtained antibacterial agent dissolved out in 5 times of acetone at 50 ℃ for 30min is 6.8%.

Example 9:

an antibacterial agent was prepared according to the method of example 1, except that divinylbenzene in step (1) was changed to 352g of pentaerythritol tetraacrylate, to finally obtain antibacterial agent # 9. The average particle diameter of the obtained antibacterial agent was 1210 nm. The weight percentage of the obtained antibacterial agent dissolved out in 5 times of acetone at 50 ℃ for 30min is 5.2%.

2. Preparation of antibacterial thermoplastics

Example 10:

100 parts by weight of polypropylene, 1.0 part by weight of antibacterial agent 1# and 0.25 part by weight of composite antioxidant are put into a low-speed mixer to be fully and uniformly stirred, then the mixed materials are melted and blended by a double-screw extruder, the temperature of the extruder is 190-220 ℃, the rotating speed is 350r.p.m, the mixture is extruded and granulated, the extruded granules are dried in a constant-temperature oven of 90 ℃ for 3 hours, and then the mixture is injected into a sample of 50mm multiplied by 50mm at the injection molding temperature of 200-220 ℃ to carry out an antibacterial test. And (3) soaking a part of sample wafers in hot water at 50 ℃ for 16 hours before the antibacterial test.

And (3) antibacterial results:

before water boiling: staphylococcus aureus: 99.9 percent; coli: 99.9 percent

After water boiling: staphylococcus aureus: 99.9 percent; coli: 99.9 percent

Comparative example 1:

the antibacterial agent 1#1.0 parts by weight in example 10 was replaced with 1.0 part by weight of polyhexamethylene biguanide hydrochloride having the same content as in example 10, and other steps were performed in the same manner as in example 10 to prepare a sample sheet for an antibacterial test.

And (3) antibacterial results:

before water boiling: staphylococcus aureus: 91.6 percent; coli: 89.6 percent

After water boiling: staphylococcus aureus: 41.5 percent; coli: 40.2 percent

The comparison result shows that the antibacterial agent not only improves the antibacterial effect, but also has better water resistance, and the antibacterial effect of the antibacterial plastic before and after water boiling is better than that of pure polyhexamethylene biguanide hydrochloride.

Example 11:

100 parts by weight of polypropylene, 0.5 part by weight of an antibacterial agent No. 3 and 0.25 part by weight of a composite antioxidant are put into a low-speed mixer to be fully and uniformly stirred, then the mixed materials are melted and blended by a double-screw extruder, the temperature of the extruder is 190-220 ℃, the rotating speed is 350r.p.m, the mixture is extruded and granulated, the extruded granules are dried in a constant-temperature oven of 90 ℃ for 3 hours, and then the mixture is injected into a sample of 50mm multiplied by 50mm at the injection molding temperature of 200-220 ℃ to carry out an antibacterial test. And (3) soaking a part of sample wafers in hot water at 50 ℃ for 16 hours before the antibacterial test.

And (3) antibacterial results:

before water boiling: staphylococcus aureus: 99.9 percent; coli: 99.9 percent

After water boiling: staphylococcus aureus: 99.9 percent; coli: 99.9 percent

Comparative example 2:

in the same manner as in example 11 except for replacing 0.5 part by weight of the antibacterial agent # 3 in example 11 with 0.5 part by weight of polyhexamethyleneguanidine hydrochloride having the same content as in example 11, a sample piece was prepared and subjected to an antibacterial test.

And (3) antibacterial results:

before water boiling: staphylococcus aureus: 55.8 percent; coli: 49.6 percent

After water boiling: staphylococcus aureus: 0; coli: 0

The comparison results show that the guanidine salt composite antibacterial agent still has good antibacterial effect after the dosage of the guanidine salt composite antibacterial agent is reduced, the water resistance after poaching is reduced, but the antibacterial effect of the antibacterial plastic before and after poaching is better than that of pure polyhexamethylene guanidine hydrochloride.

Claims

1. An antibacterial agent is a cross-linked copolymer microsphere with a guanidine salt polymer grafted on the surface, wherein the cross-linked copolymer is a cross-linked copolymer containing a structural unit A, a structural unit B and a structural unit C; the structural unit A is provided by maleic anhydride, the structural unit B is provided by a monomer M, and the structural unit C is provided by a cross-linking agent; wherein the monomer M is selected from styrene and/or alpha-methyl styrene; the cross-linking agent is selected from vinyl-containing monomers with more than two functionalities and capable of free radical polymerization;

the guanidine salt polymer is selected from at least one of polyhexamethylene (bis) guanidine inorganic salt, polyhexamethylene (bis) guanidine organic salt, polyoxyethylene guanidine inorganic salt and polyoxyethylene guanidine organic salt;

the antibacterial agent is in the form of microspheres and/or quasi-spheres; the average particle size of the antibacterial agent is 150-2000 nm.

2. The antimicrobial agent of claim 1, wherein:

the crosslinking agent is at least one of divinyl benzene and an acrylate crosslinking agent containing at least two acrylate groups.

3. The antimicrobial agent of claim 2, wherein:

the acrylate group has the structural formula: -O-C (O) -C (R') ═ CH₂Wherein R' is selected from H or alkyl of C1-C4.

4. The antimicrobial agent of claim 1, wherein:

the crosslinking agent is at least one selected from divinylbenzene, propylene glycol bis (meth) acrylate, ethylene glycol bis (meth) acrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane tetraacrylate, trimethylolpropane tetramethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, phthalic acid ethylene glycol diacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and ethoxylated multifunctional acrylate.

5. The antimicrobial agent of claim 4, wherein:

the propylene glycol bis (meth) acrylate is at least one selected from the group consisting of 1, 3-propylene glycol dimethacrylate, 1, 2-propylene glycol dimethacrylate, 1, 3-propylene glycol diacrylate and 1, 2-propylene glycol diacrylate.

6. The antimicrobial agent of claim 4, wherein:

the ethylene glycol bis (meth) acrylate is at least one selected from the group consisting of ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, tetraethylene glycol dimethacrylate and tetraethylene glycol diacrylate.

7. The antimicrobial agent of claim 1, wherein:

the average particle size of the antibacterial agent is 250-1500 nm.

8. The antimicrobial agent of claim 1, wherein:

the guanidine salt polymer is at least one selected from the group consisting of polyhexamethylene (bis) guanidine hydrochloride, polyhexamethylene (bis) guanidine phosphate, polyhexamethylene (bis) guanidine sulfonate, polyhexamethylene (bis) guanidine acetate, polyhexamethylene (bis) guanidine propionate, polyhexamethylene (bis) guanidine stearate, polyhexamethylene (bis) guanidine laurate, polyhexamethylene (bis) guanidine benzoate, polyoxyethylene guanidine hydrochloride, polyoxyethylene guanidine phosphate, polyoxyethylene guanidine sulfonate, polyoxyethylene guanidine acetate, polyoxyethylene guanidine propionate, polyoxyethylene guanidine stearate, polyoxyethylene guanidine laurate and polyoxyethylene guanidine benzoate.

9. The antimicrobial agent of claim 8, wherein:

the guanidine salt polymer is at least one selected from polyhexamethylene (bis) guanidine hydrochloride, polyhexamethylene (bis) guanidine propionate and polyoxyethylene guanidine hydrochloride.

10. The antimicrobial agent of claim 1, wherein:

the molar ratio of the structural unit A to the structural unit B is in a range of 0.5: 1-1: 0.5.

11. the antimicrobial agent of claim 10, wherein:

the molar ratio of structural unit A to structural unit B is in the range of 0.75: 1-1: 0.75.

12. the antimicrobial agent of claim 1, wherein:

the crosslinking degree of the antibacterial agent is more than or equal to 65 percent.

13. The antimicrobial agent of claim 12, wherein:

the crosslinking degree of the antibacterial agent is 75-100%.

14. The antimicrobial agent of claim 13, wherein:

the crosslinking degree of the antibacterial agent is 85-100%.

15. The antibacterial agent according to any one of claims 1 to 14, characterized in that:

the weight percentage of the antibacterial agent in 5 times of acetone is less than or equal to 10 wt% under the condition of 50 ℃ and 30 min.

16. The method for producing an antibacterial agent according to any one of claims 1 to 15, comprising reacting components including the maleic anhydride, the monomer M and the crosslinking agent, and then reacting the reaction product with the guanidine salt polymer to obtain the antibacterial agent.

17. The method for producing an antibacterial agent according to claim 16, characterized by comprising the steps of:

(1) in an organic solvent, in the presence of a first part of initiator, contacting the maleic anhydride with a first part of monomer M for reaction, and introducing a solution containing a cross-linking agent for continuous reaction to obtain a suspension product;

wherein the crosslinker-containing solution comprises the crosslinker, a second portion of monomer M, and a second portion of initiator;

(2) adding a guanidine salt polymer solution into the suspension product obtained in the step (1) to continue reacting to obtain the antibacterial agent.

18. The method for producing an antibacterial agent according to claim 17, characterized in that:

in the step (1), the raw material is processed,

the total amount of the first part of monomer M and the second part of monomer M is 50-150 mol relative to 100mol of maleic anhydride;

the molar ratio of the second part of monomers M to the first part of monomers M is (0-100): 100.

19. The method for producing an antibacterial agent according to claim 18, characterized in that:

in the step (1), the total amount of the first part of monomer M and the second part of monomer M is 75-100 mol relative to 100mol of the maleic anhydride.

20. The method for producing an antibacterial agent according to claim 17, characterized in that:

in the step (1), the raw material is processed,

the total dosage of the first part of the initiator and the second part of the initiator is 0.05-10 mol relative to 100mol of the maleic anhydride;

the molar ratio of the second part of the initiator to the first part of the initiator is (0-100): 100.

21. The method for producing an antibacterial agent according to claim 20, characterized in that:

in the step (1), the step (c),

the total amount of the first part of the initiator and the second part of the initiator is 0.8-1.5 mol relative to 100mol of the maleic anhydride.

22. The method for producing an antibacterial agent according to claim 17, characterized in that:

in the step (1), the step (c),

the initiator is a thermal decomposition type initiator.

23. The method for producing an antibacterial agent according to claim 22, characterized in that:

the initiator is at least one selected from dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, lauroyl peroxide, tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, azobisisobutyronitrile and azobisisoheptonitrile.

24. The method for producing an antibacterial agent according to claim 17, characterized in that:

in the step (1), the step (c),

the amount of the cross-linking agent is 1-40 mol relative to 100mol of the maleic anhydride.

25. The method for producing an antibacterial agent according to claim 24, characterized in that:

in the step (1), the step (c),

the amount of the cross-linking agent is 10-20 mol relative to 100mol of the maleic anhydride.

26. The method for producing an antibacterial agent according to claim 17, characterized in that:

in the step (1), the amount of the organic solvent is 50-150L relative to 100mol of the maleic anhydride.

27. The method for producing an antibacterial agent according to claim 17, characterized in that:

in the step (1), the step (c),

the organic solvent is the same as or different from the solvent of the cross-linking agent solution, and is at least one selected from organic acid alkyl ester, a mixture of the organic acid alkyl ester and alkane, and a mixture of the organic acid alkyl ester and aromatic hydrocarbon.

28. The method for producing an antibacterial agent according to claim 27, characterized in that:

the organic acid alkyl ester is selected from at least one of methyl formate, ethyl formate, propyl formate, butyl formate, isobutyl formate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, pentyl acetate, isopentyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, isobutyl butyrate, isoamyl isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate and ethyl phenylacetate.

29. The method for producing an antibacterial agent according to claim 27, characterized in that:

the alkane is selected from n-hexane and/or n-heptane.

30. The method for producing an antibacterial agent according to claim 27, characterized in that:

the aromatic hydrocarbon is at least one selected from benzene, toluene and xylene.

31. The method for producing an antibacterial agent according to claim 17, characterized in that:

in the step (1), the raw material is processed,

the reaction conditions for the reaction by contacting the maleic anhydride and the first part of the monomer M comprise:

the reaction is carried out in an inert atmosphere, the reaction temperature is 50-90 ℃, and the reaction time is 0.5-4 h;

the reaction conditions for introducing the solution containing the cross-linking agent to continue the reaction include:

the reaction temperature is 50-90 ℃; the reaction time is 2-15 h.

32. The method for producing an antibacterial agent according to claim 31, characterized in that:

in the step (1), the step (c),

the reaction is carried out in an inert atmosphere, the reaction temperature is 60-70 ℃, and the reaction time is 0.5-2 h;

the reaction temperature is 60-70 ℃.

33. The method for producing an antibacterial agent according to claim 17, characterized in that:

in the step (2), the step (c),

the dosage of the guanidine salt polymer solution is 500-10000 g relative to 1000g of maleic anhydride;

the concentration of the guanidine salt polymer solution is 0.5-50 wt%.

34. The method for producing an antibacterial agent according to claim 33, characterized in that:

in the step (2), the step (c),

the dosage of the guanidine salt polymer solution is 1000-8000 g relative to 1000g of maleic anhydride; the concentration of the guanidine salt polymer solution is 1-30 wt%.

35. The method for producing an antibacterial agent according to claim 17, characterized in that:

in the step (2), the step (c),

the reaction temperature is 0-100 ℃; the reaction time is 0.5-10 h.

36. The method for producing an antibacterial agent according to claim 35, characterized in that:

in the step (2), the step (c),

the reaction temperature is 2.5-90 ℃; the reaction time is 0.5-8 h.

37. Use of an antibacterial agent according to any one of claims 1 to 15, or prepared by the process of any one of claims 16 to 36, in the preparation of antibacterial polymers and articles thereof.