CN115260506A

CN115260506A - Flame-retardant antibacterial agent and preparation method and application thereof

Info

Publication number: CN115260506A
Application number: CN202110475518.0A
Authority: CN
Inventors: 王宇韬; 胡晨曦; 初立秋; 李�杰; 张师军; 高达利; 尹华; 白弈青
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: 2021-04-29
Filing date: 2021-04-29
Publication date: 2022-11-01

Abstract

The invention relates to a flame-retardant antibacterial agent and a preparation method and application thereof, belonging to the field of polymer processing and additives. The flame-retardant antibacterial agent is a polymer microsphere with a guanidine salt grafted on the surface, wherein the polymer microsphere comprises a crosslinking structure consisting of a structural unit A derived from maleic anhydride, a structural unit B derived from a monomer M and a structural unit C derived from a crosslinking agent, wherein the monomer M is selected from styrene and/or alpha-methyl styrene and a mixture thereof; and the guanidinium salt comprises at least one guanidinium salt having flame retardancy; the polymer microsphere as a graft base may have a shell cross-linked structure; the polymer microsphere grafted with guanidine salt has good dispersibility and compatibility in a polymer matrix, and can effectively endow the polymer matrix with good flame retardant effect and antibacterial effect.

Description

Flame-retardant antibacterial agent and preparation method and application thereof

Technical Field

The invention relates to the field of polymer processing and additives, in particular to a flame-retardant antibacterial agent and a preparation method and application thereof.

Background

In recent years, with the development of science and technology and the rise of intelligence and energy revolution, the pursuit of people for high-quality and healthy life is continuously promoted. Intelligent household appliances (such as electric toilets, intelligent refrigerators, air conditioners, washing machines and the like) and new energy automobiles also gradually enter people's lives and play an increasingly important role. The phenomena of high-rise fire, automobile deflagration and the like caused by short circuit of the product are strongly concerned by people and society. In 2020, the new coronary pneumonia virus epidemic situation spreads globally, and human puts forward more urgent new requirements on the antibacterial property and the sanitary safety of materials.

The high molecular polymer is used as one of the matrix materials widely applied to the emerging products and the anti-epidemic materials. It is itself flammable, produces a large amount of molten droplets in the combustion process and the flame spreads rapidly, the fire safety is relatively poor. In addition, the polymer does not have antibacterial performance, and an antibacterial agent needs to be additionally added to meet the sanitary requirement of the material. At present, the mainstream flame-retardant antibacterial modification technology mainly adds a commercial flame retardant and an antibacterial agent respectively. The flame-retardant modification of the polymer mainly comprises an intrinsic flame-retardant modification method and an additive modification method. Among them, the additive modification method of additionally adding a high-efficiency flame retardant into a polymer base material is widely used due to the advantages of simple operation, controllable cost, easy popularization, industrialization and the like. Flame retardants used for flame retardant modification of polymers can be mainly classified into halogen flame retardants, inorganic flame retardants, intumescent Flame Retardants (IFR), and the like. The halogen flame retardant has high flame retardant efficiency, but the application of singly adding a large amount of halogen flame retardant is increasingly limited due to serious health and environmental safety hazards in the combustion process. Although inorganic flame retardants such as magnesium hydroxide and aluminum hydroxide are environmentally friendly, they have low flame retardant efficiency and require high addition levels to achieve a certain flame retardant effect. Meanwhile, the addition of a large amount of an inorganic flame retardant component having poor dispersibility tends to have a large influence on the mechanical properties of the substrate, and is not suitable for a separate application.

The preparation of the antibacterial material mainly comprises the steps of uniformly mixing the substrate, the antibacterial agent and the process auxiliary agent according to a certain proportion, preparing the modified material with the antibacterial function through different preparation processes, and finally processing and manufacturing various antibacterial products. Currently, the antimicrobial agents used in the market mainly include inorganic and organic antimicrobial agents. The inorganic antibacterial agent is mainly an inorganic substance loaded with antibacterial metal ions (such as one or more of silver ions, zinc ions, copper ions and the like), and can be used for a variety of loaded carriers, including zeolite (natural or synthetic zeolite), zirconium phosphate, soluble glass, calcium phosphate, silica gel and the like. The organic antibacterial agents are classified according to their structures and include guanidinium salts, quaternary ammonium salts, quaternary phosphonium salts, imidazoles, pyridines, organic metals, and the like. The inorganic antibacterial agent has the characteristics of high safety, good heat resistance, long-lasting sterilization and the like, but the sterilization of the inorganic antibacterial agent is not immediate, and the price is high due to the adoption of noble metals. The organic antibacterial agent has the advantages of high sterilization speed, good antibacterial and mildewproof effects, wide application range and the like, but also has the problems of easy generation of drug resistance, poor heat resistance and the like.

As described above, the main method of flame retardant and antibacterial modification is to add flame retardant and antibacterial agent respectively to improve the flame retardant performance and antibacterial performance of the material, and chinese patent applications CN107151430a, CN 106149091a, CN 106835328A all disclose the purposes of flame retardant and antibacterial modification of the substrate by this method. Because the flame retardant and the antibacterial agent have poor dispersibility in the matrix, the addition of the flame retardant and the antibacterial agent respectively can have certain influence on the comprehensive performance of the material. In particular, in order to realize multiple functions of a polymer material, a large amount of multi-component auxiliaries are often added, and the auxiliaries may affect each other, thereby affecting the comprehensive performance of the material. For example, when a commercial antibacterial agent (Ag-based or Zn-based) is introduced, the flame retardancy of the material is lowered.

The Chinese patent application with the publication number CN111501340A discloses a preparation process of a flame-retardant antibacterial coating, although the coating technology can achieve a certain flame-retardant antibacterial effect, the coating is modified in an after-finishing mode, and the defects of poor interaction and the like between the coatings and the surface of a base material exist, so that the modified and prepared coating is easy to fall off and poor in weather resistance, and performance attenuation is inevitably caused by long-time use.

Therefore, the additive type single-component multifunctional additive with higher development efficiency can be used for effectively reducing the addition amount of the functional additive, preventing the performance repulsion among different functional additives, improving the related functional performance and comprehensive performance of the material and realizing the multi-functionalization of the high polymer material.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a flame-retardant antibacterial agent, and particularly relates to a flame-retardant antibacterial agent and a preparation method and application thereof.

It is an object of the present invention to provide a flame retardant antimicrobial agent. The flame-retardant antibacterial agent has the characteristic of single-component multifunctional modification, has good antibacterial and flame-retardant effects, can be used as a single-component multifunctional auxiliary agent to efficiently realize the multifunction of materials, and reduces the addition amount of the auxiliary agent.

It is another object of the present invention to provide a method for preparing the flame-retardant antibacterial agent, which can be easily carried out, particularly, using easily available raw materials.

It is another object of the present invention to provide use of the flame retardant antimicrobial agent. The flame-retardant antibacterial thermoplastic resin composition containing the flame-retardant antibacterial agent has a good antibacterial effect and good flame retardance, and can be particularly suitable for manufacturing compositions and products used in crowded places such as schools, hospitals and hotels, and emerging fields such as intelligent household appliances and new energy automobiles.

The present inventors have unexpectedly found that a one-component multifunctional additive having both good flame retardant effect and antibacterial effect is obtained by grafting a guanidine salt comprising at least one flame retardant guanidine salt onto the surface of crosslinked polymer microspheres formed by crosslinking and copolymerizing maleic anhydride, styrene and/or alpha-methylstyrene or a mixture thereof and a crosslinking agent, and that the polymer microspheres grafted with the guanidine salt have good dispersibility and compatibility in a polymer matrix and can effectively impart good flame retardant effect and antibacterial effect to the polymer matrix, thereby achieving the above object.

Accordingly, in a first aspect, the present invention provides a flame retardant antimicrobial agent which is a polymeric microsphere having a guanidine salt grafted on the surface thereof;

wherein the polymeric microspheres comprise a crosslinked structure composed of structural units A derived from maleic anhydride, structural units B derived from monomers M and structural units C derived from a crosslinking agent, wherein monomers M may be selected from styrene and/or alpha-methylstyrene and mixtures thereof; and, the guanidinium salt comprises at least one guanidinium salt having flame retardancy.

As used herein, "polymeric microspheres" refer to polymeric particles having diameters ranging from nano-to micro-scale, and being spherical or spheroidal in shape.

The guanidine salt grafted polymeric microspheres may have an average particle size of 200 to 3000nm, more preferably 200 to 2000nm. Specifically, it may be selected from, for example, 200nm, 250nm, 350nm, 450nm, 550nm, 650nm, 750nm, 850nm, 950nm, 1050nm, 1150nm, 1250nm, 1350nm, 1450nm, 1550nm, 1650nm, 1750nm, 1850nm, 2000nm, 2500nm, 2750nm, 3000nm, or any value therebetween. The average particle diameter is characterized by a number average particle diameter and is determined by means of a scanning electron microscope.

The polymeric microspheres are preferably monodisperse, i.e. uniform in particle size. The dispersion coefficient of the particle diameter may be 1.05 to 1.0001. Such narrow size distribution of the polymeric microspheres can advantageously promote uniform dispersion of the flame retardant antimicrobial agent of the present invention in the matrix resin, thereby facilitating uniform distribution of the grafted guanidinium salt in the resin matrix and the final product, and further providing better flame retardant and antimicrobial effects.

Preferably, the polymeric microspheres used as the grafting base comprise a crosslinked alternating copolymer structure formed from maleic anhydride, monomer M and a crosslinking agent. The microspheres can be used for favorably improving the grafting efficiency of the guanidine salt and facilitating the uniform distribution of the grafted guanidine salt in a resin matrix and a final product; due to the increased content and uniform distribution of the maleic anhydride monomer units, the flame-retardant antimicrobial microspheres are also beneficial to uniform distribution and dispersion in the resin matrix and the final product, and even additional compatilizers can be omitted.

The structural unit formed by polymerizing maleic anhydride is referred to as structural unit a, the structural unit formed by polymerizing monomer M is referred to as structural unit B, and the structural unit formed by polymerizing a crosslinking agent (or crosslinking monomer) is referred to as structural unit C. 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;

in the polymeric microspheres of the present invention, the molar ratio of the structural unit a to the structural unit B may range from (0.5.

The crosslinking degree of the guanidine salt grafted polymer microspheres can be greater than or equal to 50%, such as 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or any value therebetween, preferably greater than or equal to 70%, and more preferably greater than or equal to 90%. The crosslinking degree of the polymer microsphere is characterized by gel content and is measured by a solvent extraction method. The weight percentage of the eluted material of the polymeric microspheres after 30min in 5 times the weight of acetone at 50 ℃ is preferably 8wt% or less, e.g. 1wt%, 2wt%, 3wt%, 4wt%, 5.5wt%, 6.5wt%, 7.5wt%, 8wt% or any value in between, and correspondingly the degree of cross-linking is preferably 92% or more.

The polymer microsphere grafted with the guanidine salt preferably has a shell cross-linked structure, so that the polymer microsphere has better solvent resistance and thermal stability.

Wherein the content of the first and second substances,

as the crosslinking agent, which may also be referred to as a crosslinking monomer, any suitable crosslinking monomer may be used, preferably a difunctional or more functional vinyl-containing monomer capable of undergoing free radical polymerization. More preferably, the crosslinking agent is selected from at least one of divinylbenzene and acrylate-based crosslinking agents containing at least two acrylate-based groups.

The acrylate group preferably has the formula: -O-C (O) -C (R') = CH₂R' is H or C₁-C₄Alkyl groups of (a); more preferably, the acrylate group is an acrylate group and/or a methacrylate group.

Preferably, the crosslinking agent is selected from one or more of divinylbenzene, bis (meth) acrylates of propylene glycols, bis (meth) acrylates of ethylene glycols, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, polyethylene glycol bis (meth) acrylate, phthalic acid ethylene glycol diacrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and ethoxylated multifunctional acrylates.

The propylene glycol-based bis (meth) acrylate may be selected from one or more of 1,3-propylene glycol dimethacrylate, 1,2-propylene glycol dimethacrylate, 1,3-propylene glycol diacrylate, 1,2-propylene glycol diacrylate. The ethylene glycol-based di (meth) acrylate may be selected from one or more of ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, tetraethylene glycol dimethacrylate, tetraethylene glycol diacrylate.

Herein, the expression "(meth) acrylate" includes acrylates, methacrylates and mixtures thereof.

The guanidine salt in the invention can be selected from one or more of small molecule guanidine salt and guanidine salt polymer. Preferably, the guanidinium salt may comprise at least one small molecule guanidinium salt and at least one guanidinium salt polymer; more preferably, the small molecule guanidinium and the guanidinium polymer are both guanidinium salts having flame retardancy. The small molecule guanidine salt can be preferably selected from at least one of the following substances: guanidine phosphate, guanidine hydrochloride, guanidine nitrate, guanidine hydrobromide, guanidine oxalate, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, and aminoguanidine salts such as monoaminoguanidine, diaminoguanidine, and triaminoguanidine, such as carbonate, nitrate, phosphate, oxalate, hydrochloride, hydrobromide, and sulfonate. More preferably, the small molecule guanidine salt is selected from the group consisting of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, guanidine hydrobromide, and one or more of the nitrate, phosphate, hydrochloride, hydrobromide, and sulfonate salts of monoaminoguanidine, diaminoguanidine, and triaminoguanidine; still further preferred is one or more of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, guanidine hydrobromide, triaminoguanidine nitrate, monoaminoguanidine nitrate, triaminoguanidine phosphate, triaminoguanidine hydrochloride, triaminoguanidine hydrobromide, triaminoguanidine sulfonate.

The guanidinium polymer may preferably be selected from at least one of the following: inorganic and organic acid salts of polyhexamethylene (bis) guanidine, such as polyhexamethylene (bis) guanidine hydrochloride, polyhexamethylene (bis) guanidine phosphate, polyhexamethylene (bis) guanidine acetate, polyhexamethylene (bis) guanidine oxalate, polyhexamethylene (bis) guanidine stearate, polyhexamethylene (bis) guanidine laurate, polyhexamethylene (bis) guanidine benzoate, polyhexamethylene (bis) guanidine sulfonate; a polyoxyethylene-based guanidine salt. More preferably, the guanidine salt polymer is selected from one or more of polyhexamethylene (bis) guanidine hydrochloride, polyhexamethylene (bis) guanidine phosphate, hexamethylene (bis) guanidine sulfonate, and polyhexamethylene (bis) guanidine oxalate.

The guanidine salt grafted on the polymer microsphere according to the present invention contains at least one guanidine salt having flame retardancy, thereby realizing the polymer microsphere having both antibacterial property and flame retardancy. The flame-retardant guanidinium salt may contain a flame-retardant element, and preferably may contain a phosphorus atom, a halogen atom, and/or a nitrogen atom other than a nitrogen atom in a guanidinium group. Preferably, the flame-retardant guanidine salt is at least one selected from the group consisting of guanidine phosphate, guanidine hydrochloride, guanidine hydrobromide, guanidine dihydrogen phosphate, diguanide, guanidine hydrobromide, and aminoguanidine phosphate, hydrochloride, hydrobromide, nitrate, carbonate, oxalate, sulfonate, and polymers of the above guanidine salts; more preferably at least one selected from the group consisting of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, guanidine hydrobromide, amino guanidine phosphate, hydrochloride, hydrobromide, nitrate, sulfonate, polyhexamethylene (bis) guanidine hydrochloride and polyhexamethylene (bis) guanidine phosphate. The aminoguanidine can be one or more of monoaminoguanidine, diaminoguanidine and triaminoguanidine.

The expression "polyhexamethylene (bis) guanidine" herein refers to polyhexamethylene guanidine and/or polyhexamethylene biguanide.

The flame retardant guanidine salt can account for 30-100wt% of the total weight of the guanidine salt; preferably 50 to 100wt%; more preferably 80-100wt%, for example 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 100wt%.

In a second aspect of the present invention, the present invention provides a method for preparing the flame retardant, antibacterial agent, which may comprise the steps of: preparing polymer microspheres by subjecting maleic anhydride, the monomer M and the crosslinking agent to a crosslinking copolymerization reaction in the presence of an initiator, and contacting the polymer microspheres with a guanidine salt to graft the guanidine salt onto the polymer microspheres, thereby obtaining the flame-retardant antibacterial agent.

The polymeric microspheres are preferably prepared by a self-stabilizing precipitation polymerization process. The self-stabilization precipitation polymerization is a reaction method for preparing monodisperse polymer microspheres without adding any or dispersing agent and other auxiliary agents, the polymer microspheres can be generated in one step, and the obtained polymer microspheres have uniform appearance and size, regular structure and adjustable particle size; and ester solvents with lower toxicity can be used. The resulting polymer system has the property of being self-stabilizing. The flame-retardant antibacterial agent obtained by adopting the polymer microspheres has good dispersibility in matrix resin, and can realize better and more uniform distribution of the stabilizer of the grafted guanidine salt, thereby being beneficial to improving the flame-retardant and antibacterial effects of the flame-retardant antibacterial agent.

Specifically, the preparation method of the flame-retardant antibacterial agent can comprise the following steps:

(1) In an organic solvent, in the presence of a first part of initiator, contacting maleic anhydride and a first part of monomer M to perform partial reaction, and introducing a feed containing a crosslinking agent (preferably a solution containing the crosslinking agent) to continue the reaction, wherein a reaction system contains the maleic anhydride, the monomer M and the crosslinking agent during the continuous reaction; wherein the crosslinker-containing feed contains a crosslinker, optionally a second portion of monomer M and optionally a second portion of initiator and optionally a solvent;

(2) Adding a guanidine salt (for example, in the form of a guanidine salt solution) to the product obtained in step (1) to continue the reaction so that the guanidine salt is grafted on the surface of the product obtained in step (1).

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

the monomer M can be fed in one step (i.e. the amount of the second part of monomer M can be 0) or in two parts (i.e. the amount of the second part of monomer M is more than 0). The molar ratio between said second portion of monomers M and said first portion of monomers M may be (0-100) such as 0, 1.

The ratio of the amount of maleic anhydride to the amount of monomer M may be conventionally selected, but in a preferred embodiment, the total amount of monomer M (the total amount of the first portion of monomer M and the second portion of monomer M in terms of terminal olefins) may be 50 to 150mol, more preferably 75 to 100mol, relative to 100mol of the maleic anhydride.

And/or the presence of a gas in the gas,

the amount of the crosslinking agent used in the method of the present invention is not particularly limited as long as the desired degree of crosslinking can be achieved. Preferably, the crosslinking agent may be used in an amount of 1 to 40mol, preferably 6 to 20mol, relative to 100mol of maleic anhydride.

The type of the cross-linking agent is as described above.

The crosslinker feed may contain the crosslinker, optionally the remaining second portion of monomers M and optionally the remaining second portion of initiator and optionally a solvent, preferably in the form of a solution containing a solvent. The kind and content of the solvent in the solution containing the crosslinking agent are not particularly limited as long as the crosslinking agent, the monomer, the initiator and the like are sufficiently dissolved therein. In general, the solvent in the solution containing the crosslinking agent may be the same as the organic solvent used in the polymerization reaction, i.e., as described above, including, for example, an alkyl ester of an organic acid. The concentration of the crosslinking agent in the solution containing the crosslinking agent may be 0.2 to 3mol/L.

In step (1), the organic solvent may be a solvent commonly used in solution polymerization, particularly self-stabilization precipitation polymerization, and preferably may be at least one selected from organic acid alkyl esters or a mixture of organic acid alkyl esters and alkanes or aromatic hydrocarbons. The organic acid alkyl esters include, but are not limited to: 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. Such alkanes include, but are not limited to: n-hexane and/or n-heptane. The aromatic hydrocarbons include, but are not limited to: at least one of benzene, toluene and xylene.

The amount of the organic solvent may be conventionally selected so long as a suitable medium is provided for the reaction of step (1), and preferably, the amount of the organic solvent may be 50 to 150L with respect to 100mol of maleic anhydride.

In step (1), the initiator may be fed in one step (i.e. the amount of the second part of the initiator may be 0) or in two parts (i.e. the amount of the second part of the initiator is more than 0). The molar ratio between the second portion of initiator and the first portion of initiator may be (0 to 100) such as from 0, 1 to 100, 5 to 100, 15.

The total amount of the initiator used in the method of the present invention is not particularly limited, and preferably, the total amount of the initiator (the total amount of the first portion of the initiator and the second portion of the initiator) may be 0.05 to 10mol, preferably 0.5 to 5mol, and more preferably 0.8 to 1.5mol, relative to 100mol of maleic anhydride.

The initiator may be an agent commonly used in the art for initiating the polymerization of maleic anhydride and an olefin, for example, a thermal decomposition type initiator. Preferably, the initiator may be at least one selected from the group consisting 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 firstly contacted with the monomer M to perform partial reaction, that is, the maleic anhydride and the monomer M are not completely reacted, and only partial polymerization reaction is performed in the presence of the initiator, so that the unreacted maleic anhydride and the monomer M are subsequently reacted with the crosslinking agent. The conditions for the reaction by contacting maleic anhydride with the monomer M may be conventional conditions as long as the maleic anhydride and the monomer M are controlled to be only partially polymerized. Preferably, the conditions under which the maleic anhydride is contacted with the first portion of monomer M to effect the reaction include: the inert atmosphere (e.g., nitrogen) may be at a temperature of 50 to 90 deg.C (more preferably 60 to 80 deg.C), a pressure (gauge pressure or relative pressure) of 0.1 to 1MPa, more preferably 0.1 to 0.5MPa, and a time of 0.5 to 4 hours (more preferably 0.5 to 2 hours).

In the step (1), after the maleic anhydride is contacted with the monomer M to perform partial reaction, a feed (preferably a solution) containing a crosslinking agent is introduced to continue the reaction, thereby being particularly advantageous for forming a shell crosslinking structure. The conditions for continuing the reaction may be conventional conditions as long as each reactant is allowed to participate in the reaction as much as possible, and preferably, the conditions for continuing the reaction include: the temperature can be 50-90 ℃, the pressure can be 0.1-1 MPa, and the time can be 1-15 h. The temperature and pressure for continuing the reaction may be the same as or different from those for carrying out the reaction by contacting maleic anhydride with the monomer M as described above. According to a preferred embodiment, the introduction of the solution containing the crosslinking agent to continue the reaction may be in the form of: and (2) dropwise adding the solution containing the cross-linking agent into the product obtained in the step (1) within 1-3 h at 50-90 ℃ (further preferably 60-70 ℃), and continuing to perform heat preservation reaction for 1-4 h.

In the step (2), the guanidine salt, preferably a guanidine salt solution, more preferably an aqueous guanidine salt solution, is added to the product (suspension) obtained in the step (1), and the reaction is carried out by rapid stirring. The amount of the guanidine salt may be conventionally selected, and preferably, the guanidine salt may be used in an amount of 5g to 5000g, preferably 20g to 3000g, more preferably 100g to 2600g, further preferably 200g to 2000g, further preferably 400 g to 2000g, relative to 1000g of maleic anhydride. The concentration of the aqueous guanidinium salt solution may be from 0.5 to 50 wt.%, preferably from 1 to 30 wt.%, more preferably from 1 to 20 wt.%, more preferably from 5 to 20 wt.%. The guanidine salt solution may be used in an amount of 100 to 10000g, preferably 300 to 1000g, more preferably 400 to 8000g, more preferably 400 to 6000g, and more preferably 1000 to 6000g, relative to 1000g of maleic anhydride.

The grafting reaction in step (2) may be carried out under conventional conditions, for example, the conditions of the grafting reaction may include: the temperature is 0 to 100 ℃, preferably 2.5 to 90 ℃, more preferably 5 to 80 ℃, and further preferably 30 to 80 ℃. The reaction time may be from 0.5 to 10 hours, preferably from 0.5 to 8 hours, more preferably from 0.5 to 6 hours. The stirring speed may be 50 to 1000rpm, preferably 50 to 500rpm, and more preferably 100 to 500rpm.

In the step (2), the product obtained in the step (1) can be directly reacted with a guanidine salt solution in the form of suspension, and the product (suspension) obtained in the step (1) can be subjected to post-treatment (separation, washing and drying) and then subjected to grafting reaction. The product obtained after drying can be added into a guanidine salt solution, preferably an aqueous solution, for 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 (3) further separating the final product obtained in the step (2) to obtain the flame-retardant antibacterial microsphere product grafted with the guanidine salt. For example, the separation treatment may be 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 inventor finds that the suspension obtained in the step (1) can be directly subjected to a grafting reaction with a guanidine salt solution (preferably an aqueous solution) without an organic solvent removing step in the step (2), and the guanidine salt flame-retardant antibacterial microsphere product, namely the flame-retardant antibacterial agent, can also be effectively prepared. Therefore, according to a preferred embodiment, in the step (2), the product (suspension) obtained in the step (1) can be directly reacted with a guanidine salt solution (one-pot method), so that a mixed system containing guanidine salt flame-retardant antibacterial microspheres is obtained, and the mixed system can be further separated to obtain a guanidine salt flame-retardant antibacterial agent product, for example, the separation can be performed according to the following modes: standing for layering, wherein the organic phase is used for recycling, and the heavy phase is subjected to centrifugal separation, water washing-centrifugal separation and drying (such as vacuum drying) to obtain the flame-retardant antibacterial agent. The product post-treatment of the one-pot process only needs one-time liquid-liquid separation, solid-liquid separation, washing and drying, so that the time consumption of a single batch can be 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, distillation and purification are not needed, energy is saved, consumption is reduced, and pollution of the organic solvent to the environment can be effectively reduced.

The invention also aims to provide the application of the flame-retardant antibacterial agent or the most flame-retardant antibacterial agent prepared by the preparation method, in particular to the application in preparing flame-retardant antibacterial polymers and products thereof. The flame-retardant antibacterial agent can be used as an additive in flame-retardant antibacterial resin compositions and products (particularly fibers, films and fabrics, injection-molded parts and the like, particularly in the form of non-woven fabrics), such as flame-retardant antibacterial thermoplastic resin compositions and products, particularly in places with dense people streams, such as schools, hospitals, hotels and the like, and products in the fields of intelligent household appliances, new energy automobiles and the like.

The fourth object of the present invention is to provide a flame-retardant antibacterial thermoplastic resin composition comprising a thermoplastic resin as a matrix and the flame-retardant antibacterial agent according to the first object of the present invention or the flame-retardant antibacterial agent prepared by the method according to the second object of the present invention, preferably, the flame-retardant antibacterial agent may be used in an amount of 0.06 to 6.5 parts by weight, preferably 0.06 to 6.2 parts by weight, more preferably 0.06 to 5 parts by weight, 0.06 to 4 parts by weight, and further preferably 0.2 to 3.6 parts by weight, based on 100 parts by weight of the thermoplastic resin. The flame-retardant antibacterial agent can be one flame-retardant antibacterial agent or a compound of more than two different flame-retardant antibacterial agents,

the fifth object of the present invention is to provide a method for preparing a flame-retardant antibacterial thermoplastic resin composition, which comprises the step of melt-blending components including the thermoplastic resin and the flame-retardant antibacterial agent.

The thermoplastic resin as matrix may be selected from at least one of polyolefin, polystyrene, polyvinyl chloride, acrylonitrile/butadiene/styrene copolymer, acrylonitrile/styrene copolymer, polyoxymethylene, nylon, polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, polycarbonate, polyphenylene oxide, polyphenylene sulfide and/or at least one of alloys and mixtures of said thermoplastic resins, preferably polyolefin, in particular at least one of polyethylene and polypropylene and copolymers thereof.

In some implementations, the flame retardant antimicrobial thermoplastic resin composition of the present invention may further comprise other functional additives as desired, including but not limited to: at least one of an antioxidant, a light stabilizer, a toughening agent, a compatilizer, a pigment, a dispersing agent and the like. The dosage of the other functional additives can be 0.1 to 100 parts by weight based on 100 parts by weight of the thermoplastic resin, and the specific dosage can be adjusted according to needs.

The flame-retardant antibacterial agent has good flame-retardant and antibacterial effects, is an effective single-component flame-retardant antibacterial multifunctional auxiliary agent, and compared with the existing method of respectively adding a flame retardant and an antibacterial agent, the guanidine salt microspheres are easier to disperse in a thermoplastic resin matrix, so that the flame-retardant and antibacterial efficiency can be effectively improved.

Meanwhile, the guanidine salt flame-retardant antibacterial microspheres have good fluidity and low moisture absorption, do not stick to walls in the preparation process of the flame-retardant antibacterial thermoplastic resin composition, are easy to feed, are simple to produce and operate, and do not need excessive production condition control.

Because the microspheres comprise maleic anhydride structural units, particularly comprise a crosslinked alternating copolymer structure formed by styrene and/or alpha-methyl styrene and a mixture thereof and a crosslinking agent, the compatibility of the microspheres and a matrix resin can be obviously improved, the dispersion of the microspheres in the matrix resin can be improved, the antibacterial and flame-retardant effects and efficiency can be further improved, and even the situation that no compatibilizer is used and the adverse effect on the flame-retardant and antibacterial effects caused by the compatibilizer can be avoided can be realized.

Under the condition of preparing the microspheres by a self-stabilizing precipitation polymerization method, the obtained microspheres have uniform and regular appearance and size, can be well dispersed in matrix resin, and realize better and more uniform distribution of grafted guanidine salt in the matrix resin, thereby obtaining better flame retardant and antibacterial effects and efficiency; in addition, the obtained microspheres have controllable structures and adjustable particle sizes, so that the production process is simpler and more controllable.

The microspheres are of standard spherical structures and the particle size of the microspheres can be adjusted. As a carrier of the functional assistant, the dispersibility of the flame-retardant antibacterial agent in a polymer base material is enhanced, and the technical problem of poor dispersibility of the functional assistant in the base material is effectively solved. Compared with the commercialized grafting modification technology, the method does not need to add a coupling agent, and can directly carry out grafting modification.

The microspheres can adopt styrene and/or alpha-methyl styrene and a mixture thereof from oil refining or ethylene industry, provide a new scheme for the utilization of mixed olefin resources in petrochemical industry, and contribute to the improvement of the added value of the product. The flame retardant antimicrobial agent of the present invention also expands the technical reserves for meeting fire safety and antimicrobial requirements.

The flame-retardant antibacterial agent with the polymer nano structure provided by the invention is rare, can be added into products such as fibers, films, injection molding parts and the like, and has application prospects in the fields of flame retardance and antibacterial.

Detailed Description

While the present invention will be described in conjunction with specific embodiments thereof, it is to be understood that the following embodiments are presented by way of illustration only and not by way of limitation, and that numerous insubstantial modifications and adaptations of the invention may be made by those skilled in the art in light of the teachings herein.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and these ranges or values should be understood to encompass values close to these ranges or values. For numerical ranges, each range between its endpoints and individual point values, and each individual point value can be combined with each other to give one or more new numerical ranges, and such numerical ranges should be construed as specifically disclosed herein.

Source of raw materials

Polyethylene (PE): trade name 7042, maocai petrochemical

Polypropylene (PP): cangzhou refined GD-H-230

Polyhexamethyleneguanidine hydrochloride, shanghai high polymer industries, inc.;

polyhexamethylene guanidine propionate, shanghai high Polymer industries, inc.;

polyhexamethylene biguanide hydrochloride, industrial ltd, shanghai;

nylon 6: brand name B3S, basff

PC: polycarbonate, trade name 3113, bayer

ABS: acrylonitrile/butadiene/styrene copolymer, designation 3504, shanghai Gao Qiao

Polyhexamethylene guanidine phosphate: auxiliary agent for Buddha mountain blue peak

Guanidine dihydrogen phosphate: baishun (Beijing) chemical technology Co., ltd

Guanidine hydrobromide salt: shanghai Yanghe Biotech Co., ltd

Aminoguanidine nitrate: guangdong Weng Jiang Chemicals

Compound antioxidant: uniformly mixing an antioxidant 1010 (basf), an antioxidant 168 (basf) and calcium stearate (Shandong Haonia) according to a mass ratio of 2/2/1 to obtain the product.

Zeolite silver-loaded antimicrobial agent: xiankangwang antibacterial science and technology Limited

Testing standard and operating steps:

1. antibacterial test standard: GB/T31402-2015 plastic surface antibacterial property test method, the bacterium for detection: escherichia coli (Escherichia coli) ATCC 25922, staphylococcus aureus (Staphylococcus aureus) ATCC 6538.

2. The method comprises the following steps of (1) antibacterial testing, wherein the testing is carried out according to an antibacterial plastic detection standard GB/T31402-2015, and the specific steps are as follows: and (3) sterilizing a sample to be detected by using 75% ethanol, drying the sample, and diluting the strain by using sterile water into a bacterial suspension with a proper concentration 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 between the sample and the film. Culturing at 37 deg.C and 90% relative humidity for 18-24 hr. The bacterial liquid is washed by sterile water, diluted to a proper concentration gradient, and 0.1mL of the bacterial liquid is uniformly coated on the 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 the same.

3. The crosslinking degree of the antibacterial agent is expressed in terms of gel content and is measured by a solvent extraction method. 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％。

4. Vertical burning test (UL-94): tested according to standard GN/T2408-2008. The flammability performance of the sample was tested using a CZF-2 vertical combustion tester (Shangyuan instrument, nanjing, china). The specific classification criteria for the UL-94 test are shown below.

Grade HB: the lowest flame retardant rating in the UL-94 standard. Requiring a burn rate of less than 40 mm per minute for samples 3 to 13 mm thick; for samples less than 3 mm thick, the burn rate is less than 70 mm per minute; or extinguished before the 100 mm mark.

If the sample can not reach HB grade, it is stepless (No Rating, NR).

5. Limiting oxygen index (LOI value) experiment: testing according to the standard GB/T2406.1-2008.

1. Preparation of flame-retardant antibacterial agent (guanidine salt flame-retardant antibacterial microspheres)

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 at 70 ℃ for 3 hours;

(3) An aqueous solution of dihydroguanide phosphate (15 wt%) and an aqueous solution of polyhexamethylene biguanide hydrochloride (15 wt%) were added thereto in an amount of 2000g each, and reacted at 80 ℃ for 3 hours. And standing and layering the reacted system, centrifuging and separating the heavy phase for 20 minutes under the condition of 5000rad/min by using a centrifuge, stirring and washing the obtained solid by using 4L of water, centrifuging and separating for 20 minutes under the condition of 5000rad/min by using the centrifuge, stirring and washing the obtained solid by using 4L of water again, centrifuging and separating for 20 minutes under the condition of 5000rad/min by using the centrifuge, and drying the obtained solid in vacuum to obtain the flame-retardant antibacterial agent, namely the polymer microsphere with the guanidine salt grafted on the surface 1#. The average particle size of the obtained polymer microspheres was 1100nm. The polymer microspheres obtained were dissolved in 5 times the weight of acetone at 50 ℃ for 30min in a weight percentage of 6.8% and, correspondingly, a degree of crosslinking of 93.2%.

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 in a centrifuge to obtain crosslinked α -methylstyrene/maleic anhydride polymer microspheres, which were washed with n-hexane, purified and dried under vacuum. Then, the dried crosslinked α -methylstyrene/maleic anhydride polymer microspheres were added to 4000g of a mixed solution of an aqueous solution of guanidine dihydrogen phosphate (15 wt%) and an aqueous solution of polyhexamethylene biguanide hydrochloride (15 wt%), 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 polymer microsphere with the guanidinium polymer grafted on the surface # 2. The average particle diameter of the obtained antibacterial agent was 1090nm. The obtained antibacterial agent was dissolved in 5 times by weight of acetone at 50 ℃ for 30min to give 6.5% by weight of an eluate, and the degree of crosslinking was accordingly 93.5%.

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 in a nitrogen atmosphere;

(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) 2000g of an aqueous solution of guanidine hydrobromide (20 wt%) and 2000g of an aqueous solution of polyhexamethylene guanidine phosphate (20 wt%) were added, respectively, 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 under the condition of 5000rad/min by using a centrifuge, stirring and washing the obtained solid by using 4L of water, centrifuging and separating for 20 minutes under the condition of 5000rad/min by using the centrifuge, stirring and washing the obtained solid by using 4L of water again, centrifuging and separating for 20 minutes under the condition of 5000rad/min by using the centrifuge, and drying the obtained solid in vacuum to obtain the flame-retardant antibacterial agent, namely the polymer microsphere with the guanidine salt grafted on the surface # 3. The average particle size of the obtained polymer microspheres is 1010nm. The polymer microspheres obtained were dissolved in 5 times the weight of acetone at 50 ℃ for 30min to give a mass fraction of 5.8% and, correspondingly, a degree of crosslinking of 94.2%.

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 ℃ in a nitrogen atmosphere;

(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, 2000g of an aqueous solution of guanidine dihydrogen phosphate (20 wt%), 2000g of an aqueous solution of guanidine hydrobromide (20 wt%) and 2000g of an aqueous solution of polyhexamethylene guanidine phosphate (20 wt%) were added, and the mixture was reacted at 60 ℃ for 10 hours. And standing and layering the reacted system, centrifuging and separating the heavy phase for 20 minutes under the condition of 5000rad/min by using a centrifuge, stirring and washing the obtained solid by using 4L of water, centrifuging and separating for 20 minutes under the condition of 5000rad/min by using the centrifuge, stirring and washing the obtained solid by using 4L of water again, centrifuging and separating for 20 minutes under the condition of 5000rad/min by using the centrifuge, and drying the obtained solid in vacuum to obtain the flame-retardant antibacterial agent, namely the polymer microsphere 4# with the guanidinium grafted on the surface. The average particle size of the obtained polymer microspheres was 1030nm. The polymer microspheres obtained were dissolved in 5 times the weight of acetone at 50 ℃ for 30min in a weight percentage of 6.0% and, correspondingly, a degree of crosslinking of 94.0%.

Example 5:

(1) Dissolving 1000g of maleic anhydride, 680g of 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 styrene/maleic anhydride polymer microspheres, washing and purifying by normal hexane, and drying in vacuum.

(3) 1000g of crosslinked styrene/maleic anhydride polymer microspheres were added to 4000g of a mixed solution of aminoguanidine nitrate (15 wt%) and polyhexamethylene biguanide phosphate (15 wt%), and reacted at 50 ℃ for 6 hours. And centrifuging the reacted system for 20 minutes by a centrifuge under the condition of 5000rad/min, stirring and washing the obtained solid by 4L of water, centrifuging for 20 minutes by the centrifuge under the condition of 5000rad/min, stirring and washing the obtained solid by 4L of water again, centrifuging for 20 minutes by the centrifuge under the condition of 5000rad/min, and drying the obtained solid in vacuum to obtain the flame-retardant antibacterial agent, namely the polymer microsphere 5# with the guanidine salt polymer grafted on the surface. The average particle size of the obtained polymer microspheres was 1170nm. The polymer microspheres obtained were dissolved in 5 times the weight of acetone at 50 ℃ for 30min to give a content of 4.0% by weight, and the degree of crosslinking was accordingly 96.0%.

Example 6:

flame-retardant 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 polymer microspheres No. 6. The average particle size of the obtained polymer microspheres was 1200nm. The polymer microspheres obtained were dissolved in 5 times the weight of acetone at 50 ℃ for 30min in a weight percentage of 2.8% and, correspondingly, a degree of crosslinking of 97.2%.

Example 7:

flame-retardant antibacterial agent was prepared by following the procedure of example 1 except that divinylbenzene in the step (2) was changed to pentaerythritol tetraacrylate 360g to finally obtain polymer microspheres # 7. The average particle size of the obtained polymer microspheres was 1050nm. The weight percentage of the obtained flame-retardant antibacterial agent dissolved out in 5 times of acetone at 50 ℃ for 30min was 5.0%, and correspondingly, the degree of crosslinking was 95.0%.

2. Preparation of flame-retardant antibacterial thermoplastic

Example 8

100 parts by weight of polyethylene, 3242 parts by weight of polymer microsphere 1#3 parts by weight and 0.25 part by weight of composite antioxidant are placed into a high-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 175 ℃ -205 ℃ (175 ℃, 190 ℃, 205 ℃, 200 ℃, 195 ℃) and the rotating speed is 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then injection molding is carried out at the injection molding temperature of 190 ℃ -200 ℃ to obtain a sample, and flame retardance and antibacterial test are carried out.

Comparative example 1

Putting 100 parts by weight of polyethylene and 0.25 part by weight of composite antioxidant into a high-speed mixer, fully and uniformly stirring, then melting and blending the mixed materials by a double-screw extruder, wherein the temperature of the extruder is 175-205 ℃ (175 ℃, 190 ℃, 205 ℃, 200 ℃, 195 ℃) and the rotating speed is 350r.p.m, extruding and granulating, drying the obtained granules in a constant-temperature oven at 90 ℃ for 3 hours, then injection molding into a sample at the injection molding temperature of 190-200 ℃, and carrying out flame retardance and antibacterial test.

Example 9

Putting 100 parts by weight of nylon 6, 3.5 parts by weight of polymer microsphere No. 2 and 0.3 part by weight of composite antioxidant into a high-speed mixer, fully and uniformly stirring, then melting and blending the mixed materials by a double-screw extruder at 220-240 ℃ (220 ℃, 230 ℃, 240 ℃ and 240 ℃) and at 350r.p.m, extruding and granulating, drying the obtained granules in a constant-temperature oven at 90 ℃ for 3 hours, then injection molding into a sample at the injection molding temperature of 230-240 ℃, and carrying out flame retardance and antibacterial test.

Comparative example 2

Putting 100 weight parts of nylon 6 and 0.3 weight part of composite antioxidant into a high-speed mixer, fully and uniformly stirring, then melting and blending the mixed materials by a double-screw extruder, wherein the temperature of the extruder is 220-240 ℃ (the temperature of each section is 220 ℃, 230 ℃, 240 ℃) and 350r.p.m), extruding and granulating, drying the extruded granules in a constant-temperature oven at 90 ℃ for 3 hours, then injection molding into a sample at the injection molding temperature of 230-240 ℃, and carrying out flame retardance and antibacterial test.

Example 10

Putting 80 parts by weight of PC, 20 parts by weight of ABS, 4 parts by weight of polymer microsphere No. 3 and 0.3 part by weight of composite antioxidant into a high-speed mixer, fully and uniformly stirring, then carrying out melt blending on the mixed materials through a double-screw extruder, wherein the temperature of the extruder is 230-260 ℃ (the temperature of each section is 230 ℃, 240 ℃, 255 ℃, 260 ℃, and 240 ℃) and the rotating speed is 350r.p.m, extruding and granulating, drying the obtained granules in a constant-temperature oven at 90 ℃ for 3 hours, then carrying out injection molding at the injection molding temperature of 230-240 ℃ to obtain a sample, and carrying out flame retardant and antibacterial tests.

Comparative example 3

Putting 80 parts by weight of PC, 20 parts by weight of ABS and 0.3 part by weight of composite antioxidant into a high-speed mixer, fully and uniformly stirring, then melting and blending the mixed materials by a double-screw extruder at the temperature of 230-260 ℃ (the temperature of each section is 230 ℃, 240 ℃, 255 ℃, 260 ℃, 255 ℃ and 240 ℃) and the rotating speed is 350r.p.m, extruding and granulating, drying the obtained granules in a constant-temperature oven at 90 ℃ for 3 hours, then injection molding into a sample at the injection molding temperature of 230-240 ℃, and carrying out flame retardant and antibacterial tests.

Example 11

100 parts by weight of polypropylene, 1.6 parts by weight of polymer microsphere No. 4 and 0.25 part by weight of composite antioxidant are put into a high-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 temperature of each section is 190 ℃, 210 ℃, 220 ℃, 215 ℃, 210 ℃) and the rotating speed is 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then, standard sample strips with specified sizes are molded at the injection molding temperature of 200-220 ℃, and the flame retardance, the antibiosis and the mechanical property test are carried out.

Comparative example 4

100 parts by weight of polypropylene, 1.6 parts by weight of zeolite silver-loaded antibacterial agent and 0.25 part by weight of composite antioxidant are put into a high-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 temperature of each section is 190 ℃, 210 ℃, 220 ℃, 215 ℃, 210 ℃) and the rotating speed is 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then injection molding is carried out at the injection molding temperature of 200-220 ℃ to form standard sample strips with specified dimensions, and the flame retardance, the antibacterial property and the mechanical property test are carried out.

Example 12

100 parts by weight of polypropylene, 1.8 parts by weight of polymer microsphere No. 5 and 0.25 part by weight of composite antioxidant are put into a high-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 temperature of each section is 190 ℃, 210 ℃, 220 ℃, 215 ℃, 210 ℃) and the rotating speed is 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then, standard sample strips with specified sizes are molded at the injection molding temperature of 200-220 ℃, and the flame retardance, the antibiosis and the mechanical property test are carried out.

Comparative example 5

100 parts by weight of polypropylene, 1.8 parts by weight of aluminum hypophosphite and 0.25 part by weight of composite antioxidant are put into a high-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 temperature of each zone is 190 ℃, 210 ℃, 220 ℃, 215 ℃, and 210 ℃), the rotating speed is 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then injection molding is carried out at the injection molding temperature of 200 ℃ -220 ℃ to obtain standard sample strips with specified dimensions, and the flame retardance, the antibiosis and the mechanical property test are carried out.

Example 13

100 parts by weight of polypropylene, 3242 parts by weight of polymer microsphere, 4#1 parts by weight of polymer microsphere, 0.8 part by weight of 6# and 0.25 part by weight of composite antioxidant are put into a high-speed mixer to be fully stirred uniformly, then the mixed materials are melted and blended by a double-screw extruder, the temperature of the extruder is 190 ℃ -220 ℃ (the temperature of each section is 190 ℃, 210 ℃, 220 ℃, 215 ℃, 210 ℃) and the rotating speed is 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then the granules are molded into standard sample strips with specified sizes at the injection temperature of 200-220 ℃ to carry out flame retardance, antibacterial property and mechanical property test.

Example 14

100 parts by weight of polypropylene, 8978 parts by weight of polymer microspheres, 897 #0.8 parts by weight of polymer microspheres and 0.25 part by weight of composite antioxidant are put into a high-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 temperature of each section is 190 ℃, 210 ℃, 220 ℃, 215 ℃, 210 ℃) and the rotating speed is 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then injection molding is carried out at the injection molding temperature of 200-220 ℃ to form standard sample strips with specified sizes, and the flame retardance, the antibiosis and the mechanical property test are carried out.

Comparative example 6

(3) After the reaction, 3500g (15 wt%) of aqueous 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 polymer microsphere 8# with the surface grafted with the non-flame-retardant guanidinium salt. The average particle size of the obtained polymer microspheres was 1050nm. The polymer microspheres obtained were dissolved in 5 times the weight of acetone at 50 ℃ for 30min to give a solution with a weight percentage of 6.5% and, correspondingly, a degree of crosslinking of 93.5%.

100 parts by weight of polypropylene, 1.8 parts by weight of polymer microsphere No. 8 and 0.25 part by weight of composite antioxidant are put into a high-speed mixer to be fully and uniformly stirred, then the mixed materials are melted and blended by a double-screw extruder, the temperature of each section of the extruder is 190 ℃, 210 ℃, 220 ℃, 215 ℃, 210 ℃, and 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then, standard sample strips with specified sizes are molded at the injection molding temperature of 200-220 ℃, and the flame retardance and the antibacterial test are carried out.

Comparative example 7

100 parts by weight of polypropylene, 1.8 parts by weight of guanidine dihydrogen phosphate and 0.25 part by weight of composite antioxidant are put into a high-speed mixer to be fully and uniformly stirred, then the mixed materials are melted and blended by a double-screw extruder, the temperature of each section of the extruder is 190 ℃, 210 ℃, 220 ℃, 215 ℃, 210 ℃, and the rotating speed is 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then, the mixture is molded into a standard sample strip with a specified size at the injection molding temperature of 200-220 ℃ to carry out flame retardant and antibacterial tests.

Comparative example 8

100 parts by weight of polypropylene, 1.0 part by weight of polymer microsphere No. 8, 0.8 part by weight of guanidine dihydrogen phosphate and 0.25 part by weight of composite antioxidant are put into a high-speed mixer to be fully and uniformly stirred, then the mixed materials are melted and blended by a double-screw extruder, the temperature of each section of the extruder is 190 ℃, 210 ℃, 220 ℃, 215 ℃, 210 ℃ and the rotating speed is 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then injection molding is carried out at the injection molding temperature of 200-220 ℃ to form standard sample strips with specified sizes, and flame retardance and antibacterial test are carried out.

Comparative example 9

100 parts by weight of polypropylene and 0.25 part by weight of composite antioxidant are put into a high-speed mixer to be fully and uniformly stirred, then the mixed materials are melted and blended by a double-screw extruder, the temperature of each section of the extruder is 190 ℃, 210 ℃, 220 ℃, 215 ℃, 210 ℃ and the rotating speed is 350r.p.m, the mixture is extruded and granulated, the obtained granules are dried in a constant-temperature oven at 90 ℃ for 3 hours, then injection molding is carried out at the injection molding temperature of 200-220 ℃ to form standard sample strips with specified dimensions, and flame retardance and antibacterial test are carried out.

Table 1: formulation of the example and comparative example compositions

Table 2: comparison of the Properties of the example and comparative example compositions

As can be seen from the test results in tables 1 and 2, thermoplastic resins such as PE, PP and PC/ABS alloy are extremely flammable and have no antibacterial property.

Examples 8 to 11 are flame retardant antibacterial thermoplastic resin (PE, PA, PC/ABS and PP) compositions according to the present invention using the flame retardant antibacterial microspheres of the present invention. As can be seen from the table 2, compared with the pure thermoplastic compositions respectively and sequentially, the thermoplastic resin composition added with the antibacterial flame-retardant microspheres has excellent antibacterial performance, can reach HB (British Standard) level or even V-2 level of UL-94 test under the condition of lower flame retardant addition, and shows good self-extinguishing property.

Examples 11 to 14 are flame retardant and antibacterial PP compositions using the flame retardant and antibacterial agent of the present invention. Comparing example 11 with comparative example 4\9, it can be seen that the addition of commercial antibacterial agent can improve the antibacterial performance of the material, but at the same time, the limiting oxygen index of the PP composition is reduced, and there is a problem of application of "this trade-off" between flame retardancy and antibacterial performance. Has no effect on improving the flame retardant property of the composition. The prepared microsphere can simultaneously improve the flame retardant and antibacterial properties of the material, and solve the application problem that the flame retardant property of the composition is reduced by the addition of commercial antibacterial agents.

Comparing example 12 with comparative example 5, it can be seen that the introduction of the commercial flame retardant can only simply improve the flame retardant property of the material, and cannot impart the antibacterial property to the material, while the microspheres prepared by the invention can simultaneously improve the flame retardant property and the antibacterial property of the material, and the flame retardant efficiency is similar to that of the commercial flame retardant, and the microspheres are a single-component multifunctional additive with potential application value in thermoplastic resin compositions.

In addition, examples 13 and 14 are flame retardant antibacterial PP compositions compounded by different flame retardant antibacterial microspheres of the present invention. Examples 13 and 14 exhibited higher limiting oxygen indices than example 12 with bead 5# added alone.

Comparative examples 6 to 8 show that the addition of the non-flame-retardant guanidinium salt modified beads (comparative example 6), the flame-retardant guanidinium salt (comparative example 7) alone and the addition of the non-flame-retardant guanidinium salt modified beads and the flame-retardant guanidinium salt (comparative example 8) simultaneously can not achieve the technical effects of both flame retardance and antibacterial property achieved by the flame-retardant antibacterial agent of the invention. The single-component flame-retardant antibacterial agent provided by the invention can realize the multifunction of the material more efficiently. Solves the technical problem that the flame retardant property of the material is reduced due to the introduction of commercial antibacterial agents (Ag series and Zn series), and reduces the influence of the introduction of functional additives on the comprehensive performance of the material.

Although the present invention has been described in detail and illustrated by way of examples, other modifications and variations within the spirit and scope of the invention will be apparent to those skilled in the art. Further, it should be understood that the various aspects recited herein, portions of different embodiments, and various features recited may be combined or interchanged either in whole or in part. Furthermore, those skilled in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention.

Claims

1. A flame-retardant antibacterial agent is a polymer microsphere with guanidine salt grafted on the surface,

wherein the polymeric microspheres comprise a crosslinked structure composed of structural units A derived from maleic anhydride, structural units B derived from monomers M selected from styrene and/or alpha-methylstyrene and mixtures thereof, and structural units C derived from a crosslinking agent; and the guanidinium salt comprises at least one guanidinium salt having flame retardancy;

preferably, the polymeric microspheres as a grafting base have a shell cross-linked structure;

preferably, the average particle size of the polymer microspheres is 200-3000nm; more preferably, the average particle diameter is 200 to 2000nm.

2. The flame retardant, antimicrobial agent of claim 1, wherein:

the polymeric microspheres used as the grafting base comprise a crosslinked alternating copolymer structure formed from maleic anhydride, monomer M and a crosslinking agent.

3. The flame retardant, antimicrobial agent of claim 1, wherein:

the crosslinking degree of the polymer microsphere is more than or equal to 50 percent, preferably more than or equal to 70 percent, and more preferably more than or equal to 90 percent; preferably, the weight percentage of the dissolved substance of the polymer microspheres in 5 times of weight of acetone at 50 ℃ for 30min is less than or equal to 8wt%.

4. The flame retardant, antimicrobial agent of claim 1, wherein:

the molar ratio of the structural unit a to the structural unit B is in the range of (0.5.

5. A flame-retardant antibacterial agent according to any one of claims 1 to 4, characterized in that:

the cross-linking agent is selected from bifunctional or more than bifunctional vinyl-containing monomers capable of free radical polymerization; preferably, the crosslinking agent is selected from at least one of divinylbenzene and an acrylate crosslinking agent containing at least two acrylate groups; the structural formula of the acrylate group is preferably: -O-C (O) -C (R') = CH₂R' is selected from H or C1-C4 alkyl; more preferably, the acrylate group is an acrylate group and/or a methacrylate group;

more preferably, the crosslinking agent is selected from one or more of divinylbenzene, bis (meth) acrylates of propylene glycols, bis (meth) acrylates of ethylene glycols, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, polyethylene glycol bis (meth) acrylate, phthalic acid ethylene glycol diacrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and ethoxylated multifunctional acrylates; more preferably, the propylene glycol-based bis (meth) acrylate is selected from one or more of 1,3-propylene glycol dimethacrylate, 1,2-propylene glycol dimethacrylate, 1,3-propylene glycol diacrylate, 1,2-propylene glycol diacrylate; the ethylene glycol-based di (meth) acrylate is selected from one or more 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.

6. A flame-retardant antibacterial agent according to any one of claims 1 to 4, characterized in that:

the guanidine salt is selected from one or more of small molecule guanidine salt and guanidine salt polymer, preferably, the guanidine salt comprises at least one small molecule guanidine salt and at least one guanidine salt polymer; more preferably, the small molecule guanidinium and the guanidinium polymer are both flame retardant guanidinium;

wherein the small molecule guanidine salt is preferably selected from at least one of the following substances: inorganic acid salts and organic acid salts of guanidine phosphate, guanidine hydrochloride, guanidine nitrate, guanidine hydrobromide, guanidine oxalate, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, and aminoguanidine salts; more preferably one or more selected from the group consisting of nitrate, phosphate, hydrochloride, hydrobromide and sulfonate salts of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate and monoaminoguanidine, diaminoguanidine and triaminoguanidine; wherein the aminoguanidine salt is preferably at least one selected from monoaminoguanidine, diaminoguanidine and triaminoguanidine; the inorganic acid salt is preferably selected from at least one of the following: carbonates, nitrates, phosphates, hydrochlorides; the organic acid salt is preferably at least one selected from oxalate, hydrobromide and sulfonate; still further preferred are one or more of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, guanidine hydrobromide, triaminoguanidine nitrate, monoaminoguanidine nitrate, triaminoguanidine phosphate, triaminoguanidine hydrochloride, triaminoguanidine hydrobromide, triaminoguanidine sulfonate;

the guanidinium polymer is preferably selected from at least one of the following: inorganic and organic acid salts of polyhexamethylene (bis) guanidine; more preferably at least one selected from the group consisting of: polyhexamethylene (bis) guanidine hydrochloride, polyhexamethylene (bis) guanidine phosphate, polyhexamethylene (bis) guanidine acetate, polyhexamethylene (bis) guanidine oxalate, polyhexamethylene (bis) guanidine stearate, polyhexamethylene (bis) guanidine laurate, polyhexamethylene (bis) guanidine benzoate, polyhexamethylene (bis) guanidine sulfonate, polyoxyethylene guanidine salt; more preferably, the guanidine salt polymer is selected from one or more of polyhexamethylene (bis) guanidine hydrochloride, polyhexamethylene (bis) guanidine phosphate, hexamethylene (bis) guanidine sulfonate, and polyhexamethylene (bis) guanidine oxalate.

7. A flame-retardant antibacterial agent according to any one of claims 1 to 4, characterized in that:

the flame-retardant guanidinium salt contains a flame-retardant element, preferably containing a phosphorus atom, a halogen atom and/or a nitrogen atom other than a nitrogen atom in a guanidinium group; preferably at least one member selected from the group consisting of guanidine phosphate, guanidine hydrochloride, guanidine hydrobromide, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, guanidine hydrobromide, and aminoguanidine phosphate, hydrochloride, hydrobromide, nitrate, carbonate, oxalate, sulfonate, and polymers of the guanidine salts; wherein the aminoguanidine is preferably at least one selected from monoaminoguanidine, diaminoguanidine and triaminoguanidine; the flame-retardant guanidine salt is more preferably one or more selected from the group consisting of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, guanidine hydrobromide, amino guanidine phosphate, hydrochloride, hydrobromide, nitrate, sulfonate, polyhexamethylene (bis) guanidine hydrochloride, and polyhexamethylene (bis) guanidine phosphate.

8. A flame-retardant antibacterial agent according to any one of claims 1 to 4, characterized in that:

the flame-retardant guanidine salt accounts for 30-100wt% of the total weight of the guanidine salt; preferably 50 to 100wt%; more preferably 80 to 100wt%.

9. A method of preparing a flame-retardant antibacterial agent according to any one of claims 1 to 8, characterized by comprising the steps of: preparing polymer microspheres by subjecting maleic anhydride, the monomer M and the crosslinking agent to a crosslinking copolymerization reaction in the presence of an initiator, and contacting the polymer microspheres with a guanidine salt to graft the guanidine salt onto the polymer microspheres, thereby obtaining the flame-retardant antibacterial agent.

10. The method of claim 9, wherein:

the polymeric microspheres used as the grafting base were prepared by a self-stabilizing precipitation polymerization process.

11. Method according to claim 9 or 10, characterized in that it comprises the following steps:

(1) In an organic solvent, in the presence of a first part of initiator, contacting maleic anhydride with a first part of monomer M to perform partial reaction, and introducing a feed containing a cross-linking agent to continue the reaction; wherein the crosslinker-containing feed contains a crosslinker, optionally a second portion of monomer M and optionally a second portion of initiator and optionally a solvent;

(2) Adding a guanidine salt, preferably a guanidine salt solution, to the product obtained in step (1), and continuing the reaction so that the guanidine salt is grafted on the surface of the product obtained in step (1).

12. The method of claim 11, wherein:

the organic solvent is at least one of organic acid alkyl ester or a mixture of the organic acid alkyl ester and alkane or aromatic hydrocarbon; the organic acid alkyl ester is preferably 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;

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

the aromatic hydrocarbon is preferably at least one selected from the group consisting of benzene, toluene and xylene.

13. The method of claim 11, wherein:

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

the total amount of the first part of monomer M and the second part of monomer M in terms of terminal olefin is 50-150 mol relative to 100mol of maleic anhydride; preferably 75 to 100mol; the molar ratio of the second part of the monomers M to the first part of the monomers M is (0-100): 100; and/or the presence of a gas in the gas,

the amount of the crosslinking agent is 1 to 40mol, preferably 6 to 20mol, relative to 100mol of maleic anhydride.

14. The method of claim 11, wherein:

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 0.05 to 10mol, preferably 0.5 to 5mol, and more preferably 0.8 to 1.5mol relative to 100mol of maleic anhydride; the molar ratio of the second part of the initiator to the first part of the initiator is (0-100): 100; and/or the presence of a gas in the gas,

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.

15. The method of claim 11,

in the step (1), the reaction of contacting maleic anhydride with the first part of monomer M is carried out at a temperature of 50-90 ℃, preferably 60-80 ℃ under an inert atmosphere; and/or the presence of a gas in the gas,

in said step (1), the further reaction of introducing the feed containing the crosslinking agent is carried out at a temperature of 50 to 90 ℃.

16. The method of claim 11,

in the step (2), the reaction is carried out at a temperature of 0 to 100 ℃, preferably 2.5 to 90 ℃; and/or the presence of a gas in the atmosphere,

in the step (2), the dosage of the guanidine salt is 5-5000 g, preferably 20-3000 g, and more preferably 100-2600 g relative to 1000g of maleic anhydride; preferably, the guanidinium salt is added in the form of a guanidinium salt solution, preferably an aqueous guanidinium salt solution; and/or the presence of a gas in the gas,

in the step (2), the product obtained in the step (1) is directly reacted with a guanidine salt solution in a suspension form or after being dried.

17. Use of a flame retardant, antibacterial agent according to any one of claims 1 to 8 or prepared according to the process of any one of claims 9 to 16, preferably as an additive in flame retardant, antibacterial resin compositions and articles; the article is preferably a fiber, film, fabric, or injection molded part; the resin composition is preferably a thermoplastic resin.

18. A flame retardant antibacterial thermoplastic resin composition comprising a thermoplastic resin as a matrix and the flame retardant antibacterial agent of any one of claims 1 to 8 or the flame retardant antibacterial agent produced according to the method of any one of claims 9 to 16, preferably in an amount of 0.06 to 6.5 parts by weight, preferably 0.06 to 6.2 parts by weight, based on 100 parts by weight of the thermoplastic resin.

19. The method for preparing a flame retardant antibacterial thermoplastic resin composition according to claim 18, comprising the step of melt blending components including the thermoplastic resin, the flame retardant antibacterial agent.