Flame retardant antibacterial agent, its preparation method and use, and flame retardant antibacterial thermoplastic resin composition

Abstract

Disclosed herein are a flame-retardant antibacterial agent, its preparation method, its use, and a flame-retardant antibacterial thermoplastic resin composition. The flame-retardant antibacterial agent is a polymer microsphere having a surface grafted with a guanidine salt, the polymer microsphere comprising a crosslinked structure composed of structural unit A derived from maleic anhydride, structural unit B derived from a monomer M, and structural unit C derived from a crosslinking agent. The monomer M is selected from a C4-C9 aliphatic olefin or a mixture thereof, and the guanidine salt comprises at least one guanidine salt having flame-retardant properties. The flame-retardant antibacterial agent has both good antibacterial and flame-retardant effects, is an effective single-component multifunctional adjuvant, has very good flame-retardant and antibacterial efficiency, and also has good dispersion, good flowability, and low moisture absorption. The flame-retardant antibacterial thermoplastic resin composition containing the flame-retardant antibacterial agent also has good flame-retardant and antibacterial performance and good overall performance.

Description

Detailed Description of the Invention

[0001] [Technical Field] The present invention relates to the field of polymer processing and additives, and further to a flame retardant antimicrobial agent, a method for preparing and using the same, and flame retardant antimicrobial thermoplastic compositions and articles containing the flame retardant antimicrobial agent.

[0002] [Background technology] In recent years, with the rise of the intelligent and electrical revolution and the development of science and technology, people's pursuit of a high-quality, healthy life has continued to improve. Smart home appliances (e.g., electric toilets, smart refrigerators, air conditioners, washing machines) and new energy vehicles have also gradually become integrated into people's lives, playing an increasingly important role. The safety and health requirements and standards for these technological products are rising, with fire safety and hygiene becoming top of mind and receiving widespread research and reporting. These products have certain requirements for both the flame retardancy of the materials used (UL-94 vertical flame test, glow-wire flammability test) and hygiene.

[0003] Currently, thermoplastic resins such as polypropylene (PP) are one of the most widely used and fastest-growing types of commodity plastics. Thermoplastic resins have excellent properties, such as high stiffness, high strength, good heat resistance, and easy processability, making them one of the matrix materials widely used in the emerging products mentioned above. However, PP itself is flammable and generates large amounts of molten droplets during combustion, resulting in rapid flame spread, making it less fire-safe. Furthermore, PP also needs to be antibacterially modified to improve the hygienic aspects of the material. There are two main methods for flame-retardant modification of PP: intrinsic flame-retardant modification and additive modification. Additive modification, which adds highly efficient flame retardancy to PP, is widely used due to its advantages of simple operation, cost control, ease of acceleration, and ease of industrialization. Flame retardants used in PP mainly include halogenated flame retardants, inorganic flame retardants, and intumescent flame retardants (IFRs). Although halogenated flame retardants have relatively high flame retardant efficiency in PP, their use is increasingly restricted due to serious safety and environmental risks. Inorganic flame retardants, such as magnesium hydroxide and aluminum hydroxide, are environmentally harmless, but their flame retardant efficiency is low and larger amounts are required to achieve a certain level of flame retardancy. In addition, they have poor dispersibility in PP and have a significant impact on the mechanical properties of the matrix, making them unsuitable for separate use. IFR flame retardants have the advantages of high flame retardant efficiency, low smoke, and low toxicity. The combination of low amounts of halogenated, phosphorus-based, and nitrogen-based flame retardants synergistically improves flame retardant efficiency and is widely recognized as an effective route to achieving low-halogen or non-halogenated flame retardants. Because flame retardants generally suffer from issues such as high matrix loading and poor dispersibility, flame retardant synergists are introduced to improve flame retardant efficiency, which also reduces the impact of large amounts of flame retardants on material processability and mechanical properties.

[0004] The preparation of antibacterial plastics mainly involves homogeneously mixing a matrix resin, an antibacterial agent, and processing aids in a certain ratio; then directly melt-blending them to prepare a modified resin with antibacterial function; and finally, manufacturing various antibacterial articles using various plastic processing methods (e.g., extrusion, injection molding, casting, blow molding, blister molding, etc.). Currently, commercially available antibacterial agents are mainly divided into two categories: inorganic and organic antibacterial agents. Inorganic antibacterial agents are primarily inorganic substances that support antibacterial metal ions (e.g., one or more of silver ions, zinc ions, copper ions, etc.). There are many types of carriers that can be used for the support, including zeolite (natural or synthetic zeolite), zirconium phosphate, soluble glass, calcium phosphate, silica gel, etc. Organic antibacterial agents are classified according to their structure, and include guanidine salts, quaternary ammonium salts, quaternary phosphonium salts, imidazole, pyridine, and organic metals. Inorganic antibacterial agents are characterized by high safety, excellent heat resistance, and long-term sterilization capability. However, their sterilization is not immediate, and the use of precious metals leads to their high price. Organic antibacterial agents have the advantages of rapid sterilization speed, good antibacterial and antifungal effects, and a wide range of applications, but they also have problems such as the tendency to develop drug resistance and poor heat resistance.

[0005] Currently, researchers primarily achieve improvements in the flame retardancy and antibacterial properties of materials by adding flame retardants and antibacterial agents separately (see, for example, Chinese Patent Application Publication Nos. CN107151430A, CN106149091A, and CN106835328A). Due to poor dispersion of both the flame retardant and antibacterial agent in the matrix, adding them separately can have a detrimental effect on the overall performance of the material. In particular, achieving multifunctionality in polymer materials often requires the separate addition of large amounts of multiple additives. However, it should be noted that various additives can interact with each other, thereby affecting the overall performance of the material. For example, the introduction of commercially available antibacterial agents (such as Ag and Zn-based agents) will reduce the flame retardancy of the material.

[0006] Therefore, in order to effectively realize the multifunctionalization of polymeric materials, it is necessary to develop more efficient single-component multifunctional additives.

[0007] DISCLOSURE OF THE INVENTION In view of the above problems existing in the prior art, one object of the present invention is to provide a flame-retardant antibacterial agent that can have both good antibacterial effect and good flame-retardant effect, and can be used as a single-component multifunctional additive to effectively realize multifunctionalization of materials.

[0008] Another object of the present invention is to provide a method for preparing a flame retardant antimicrobial agent that is easy to carry out and in particular that makes use of readily available raw materials.

[0009] Another object of the present invention is to provide a flame-retardant antibacterial thermoplastic resin composition containing the above-mentioned flame-retardant antibacterial agent, which has both good antibacterial effect and good flame retardancy, and is particularly suitable for producing resin compositions and articles for use in crowded places such as schools, hospitals, and hotels, as well as emerging fields such as smart home appliances and new energy vehicles.

[0010] It has been unexpectedly discovered that a single-component multifunctional additive having excellent flame retardancy and antibacterial properties can be obtained by grafting at least one flame-retardant guanidine salt onto the surface of crosslinked polymer microspheres formed by crosslinking copolymerization of maleic anhydride, a C4-C9 aliphatic olefin, or a mixture thereof with a crosslinking agent. Such guanidine salt-grafted polymer microspheres have excellent dispersibility and compatibility in the polymer matrix, and can effectively impart excellent flame retardancy and antibacterial properties to the polymer matrix, thereby achieving the above-mentioned objectives.

[0011] Thus, in a first aspect, the present invention provides a flame retardant antimicrobial agent which is a polymer microsphere having a guanidine salt grafted onto its surface, the agent comprising: The polymer microspheres comprise a crosslinked structure composed of structural units A derived from maleic anhydride, structural units B derived from a monomer M, and structural units C derived from a crosslinking agent, wherein the monomer M is selected from the group consisting of C4-C9 aliphatic olefins and mixtures thereof; The guanidine salt provides a flame retardant antimicrobial agent comprising at least one flame retardant guanidine salt.

[0012] As used herein, the term "polymeric microsphere" refers to polymer particles having diameters ranging from the nanoscale to the microscale and having a spherical or spheroidal shape.

[0013] The guanidine salt-grafted polymer microspheres preferably have an average particle size in the range of 200 to 2000 nm, such as 200 nm, 250 nm, 350 nm, 450 nm, 550 nm, 650 nm, 750 nm, 850 nm, 950 nm, 1050 nm, 1150 nm, 1250 nm, 1350 nm, 1450 nm, 1550 nm, 1650 nm, 1750 nm, 1850 nm, 2000 nm, or any value in between, characterized by the number average particle size as measured by scanning electron microscopy.

[0014] The polymer microspheres are preferably monodisperse, i.e., polymer microspheres with a uniform particle size. The particle size distribution coefficient can be 1.05 to 1.0001. Such polymer microspheres with a narrow particle size distribution advantageously promote uniform dispersion of the flame-retardant antibacterial agent of the present invention in the matrix resin, thereby facilitating uniform distribution of the grafted guanidine salt in the resin matrix and the final product, thereby providing better flame retardant and antibacterial effects.

[0015] Preferably, the polymer microspheres as the graft substrate comprise a crosslinked alternating copolymer structure formed from maleic anhydride, a monomer M, and a crosslinking agent. The use of such microspheres can advantageously improve the grafting efficiency of the guanidine salt and facilitate the uniform distribution of the grafted guanidine salt in the resin matrix and the final product; the increased content and uniform distribution of maleic anhydride monomer units are also beneficial to the uniform distribution and dispersion of the flame-retardant antimicrobial microspheres in the resin matrix and the final product, or even the use of an additional compatibilizer is not necessary.

[0016] Here, the structural unit formed after polymerization of maleic anhydride is referred to as structural unit A, the structural unit formed after polymerization of monomer M is referred to as structural unit B, and the structural unit formed after polymerization of the crosslinking agent (or crosslinkable monomer) is referred to as structural unit C.

[0017] wherein said monomer M is selected from the group consisting of C4-C9 aliphatic olefins and mixtures thereof, preferably C4 and / or C5 aliphatic monoolefins or diolefins, or mixtures of their isomers, or mixtures of monoolefins and diolefins, such as trans-2-butene, cis-2-butene, n-butene, isobutene, or mixtures thereof, or isoprene, cyclopentadiene, 1,4-pentadiene, piperylene, 1-pentene, 2-pentene, cyclopentene, 2-methyl-1-butene, 2-methyl-2-butene, or mixtures thereof.

[0018] The monomer M can be a C4 and / or C5 fraction from an oil refinery or the ethylene industry, preferably a C4 and / or C5 fraction from ethylene cracking in the petrochemical industry. The C4 fraction from ethylene cracking can include trans-2-butene, cis-2-butene, n-butane, n-butene, isobutene, and other substances. The C5 fraction from ethylene cracking can include diolefins (isoprene, cyclopentadiene, 1,4-pentadiene, piperylene), monoolefins (1-pentene, 2-pentene, cyclopentene, 2-methyl-1-butene, 2-methyl-2-butene), alkanes (n-pentane, isopentane, cyclopentane, 2-methylbutane), alkynes (but-2-yne, 3-penten-1-yne), and other substances. As ethylene cracking products, C4 and C5 fractions are readily available, and the use of such mixed monomers to prepare polymer microspheres can help increase the added value of C4 and C5 fractions and reduce the cost of the process of the present invention.

[0019] In the polymer microspheres of the present invention, the molar ratio of structural unit A to structural unit B may be in the range of (0.5:1) to (1:0.5), preferably (0.75:1) to (1:0.75).

[0020] The crosslinking degree of the guanidine salt-grafted polymer microspheres can be ≧50%, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or any value between the above values, preferably ≧70%, more preferably ≧90%. The crosslinking degree of the polymer microspheres is measured by solvent extraction and characterized by gel content. The weight percentage of the eluted material from the polymer microspheres after 30 minutes at 50°C in acetone 5 times the weight of the polymer microspheres is preferably ≦8 wt%, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5.5 wt%, 6.5 wt%, 7.5 wt%, 8 wt%, or any value between the above values, and correspondingly, the crosslinking degree is preferably ≧92%.

[0021] The guanidine salt grafted polymer microspheres preferably have a shell crosslinked structure and therefore have better solvent resistance and thermal stability.

[0022] The crosslinking agent, which may also be referred to as a crosslinking monomer, may be any suitable crosslinking monomer, preferably a difunctional or polyfunctional vinyl-containing monomer capable of free radical polymerization. More preferably, the crosslinking agent is at least one selected from the group consisting of divinylbenzene and an acrylate-based crosslinking agent containing at least two acrylate-like groups.

[0023] The acrylate-like group preferably has the structural formula: -OC(O)-C(R')=CH2, where R' is H or a C1-C4 alkyl group, more preferably the acrylate-like group is an acrylate group and / or a methacrylate group.

[0024] Preferably, the crosslinking agent is one or more selected from the group consisting of divinylbenzene, propylene glycol-based bis(meth)acrylate, ethylene glycol-based bis(meth)acrylate, trimethylolpropane tri(meth)acrylate, bis(trimethylolpropane) tetra(meth)acrylate, polyethylene glycol bis(meth)acrylate, phthalate ethylene glycol diacrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and ethoxylated multifunctional acrylates.

[0025] The propylene glycol bis(meth)acrylate may be one or more 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. The ethylene glycol bis(meth)acrylate may be one or more 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.

[0026] As used herein, the term "(meth)acrylate" includes acrylates, methacrylates, and mixtures thereof.

[0027] The guanidine salt in the present invention may be one or more selected from the group consisting of small molecular guanidine salts and guanidine salt polymers. Preferably, the guanidine salt comprises at least one small molecular guanidine salt and at least one guanidine salt polymer, and more preferably, both the small molecular guanidine salt and the guanidine salt polymer are flame-retardant guanidine salts.

[0028] The small molecule guanidine salt is preferably at least one selected from the following: guanidine phosphate, guanidine hydrochloride, guanidine nitrate, guanidine hydrobromide, guanidine oxalate, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, and aminoguanidine salts, such as inorganic and organic acid salts of mono-, di-, and triaminoguanidine, such as carbonates, nitrates, phosphates, oxalates, hydrochlorides, hydrobromides, and sulfonates. More preferably, the small molecule guanidine salt is one or more selected from the group consisting of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, and nitrate, phosphate, hydrochloride, hydrobromide, and sulfonate salts of monoaminoguanidine, diaminoguanidine, and triaminoguanidine; even more preferably, it is one or more selected from the group consisting of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, guanidine hydrobromide, triaminoguanidine nitrate, monoaminoguanidine nitrate, triaminoguanidine phosphate, triaminoguanidine hydrochloride, triaminoguanidine hydrobromide, and triaminoguanidine sulfonate.

[0029] The guanidine salt polymer is preferably at least one selected from the following substances: inorganic and organic acid salts of polyhexamethylene(bi)guanidine, such as polyhexamethylene(bi)guanidine hydrochloride, polyhexamethylene(bi)guanidine phosphate, polyhexamethylene(bi)guanidine acetate, polyhexamethylene(bi)guanidine oxalate, polyhexamethylene(bi)guanidine stearate, polyhexamethylene(bi)guanidine laurate, polyhexamethylene(bi)guanidine benzoate, polyhexamethylene(bi)guanidine sulfonate, and polyoxyethylene guanidine salts. More preferably, the guanidine salt polymer is one or more selected from the group consisting of polyhexamethylene(bi)guanidine hydrochloride, polyhexamethylene(bi)guanidine phosphate, hexamethylene(bi)guanidine sulfonate, and polyhexamethylene(bi)guanidine oxalate.

[0030] The guanidine salt grafted onto the polymer microspheres of the present invention comprises at least one flame-retardant guanidine salt, thereby realizing polymer microspheres with both antibacterial and flame-retardant properties. The flame-retardant guanidine salt comprises a flame-retardant element, preferably a phosphorus atom, a halogen atom, and / or a nitrogen atom other than the nitrogen atom of the guanidine 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, diguanidine hydrogen phosphate, aminoguanidine phosphate, hydrochloride, hydrobromide, nitrate, carbonate, oxalate, sulfonate, and the guanidine salt polymer; more preferably, at least one selected from the group consisting of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, aminoguanidine phosphate, hydrochloride, hydrobromide, nitrate, sulfonate, polyhexamethylene(bi)guanidine hydrochloride, and polyhexamethylene(bi)guanidine phosphate. The aminoguanidine may be at least one selected from the group consisting of monoaminoguanidine, diaminoguanidine, and triaminoguanidine.

[0031] The expression "polyhexamethylene(bi)guanidine" as used herein refers to polyhexamethylene guanidine and / or polyhexamethylene biguanide.

[0032] The flame-retardant guanidine salt may constitute 30 to 100% by weight, preferably 50 to 100% by weight, more preferably 80 to 100% by weight, of the total weight of the guanidine salt; for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100% (by weight).

[0033] In a second aspect of the present invention, there is provided a method for preparing the flame-retardant antimicrobial agent of the present invention, comprising cross-linking copolymerizing maleic anhydride, a monomer M and a cross-linking agent in the presence of an initiator to prepare polymer microspheres, and contacting the polymer microspheres with a guanidine salt to graft the guanidine salt onto the polymer microspheres, thereby obtaining the flame-retardant antimicrobial agent.

[0034] The polymer microspheres are preferably prepared by self-stabilizing precipitation polymerization. Self-stabilizing precipitation polymerization is a reaction method for preparing monodisperse polymer microspheres without the addition of stabilizers, dispersants, or other additives. The polymer microspheres can be produced in a single process. The resulting polymer microspheres are uniform in morphology and size, regular, have controllable structures, and have adjustable particle sizes. Lower-toxicity ester solvents can be used. The resulting polymer system has self-stabilizing properties. The flame-retardant antibacterial agent obtained using the polymer microspheres has good dispersibility in the matrix resin, achieving better and more uniform distribution of the grafted guanidine salt, thereby facilitating improved flame-retardant and antibacterial effects of the flame-retardant antibacterial agent.

[0035] Specifically, the method for preparing the flame-retardant antimicrobial agent according to the present invention may include the following steps: (1) contacting maleic anhydride with a first portion of monomer M in an organic solvent and in the presence of a first portion of an initiator to effect a partial reaction, and then introducing a crosslinker-containing feed, preferably a solution containing a crosslinker, to effect a subsequent reaction, during which the reaction system comprises maleic anhydride, monomer M, and crosslinker; the crosslinker-containing feed comprising the crosslinker, optionally a second portion of monomer M, and optionally a second portion of an initiator, and optionally a solvent; (2) A step of adding a guanidine salt, for example a solution of a guanidine salt, to the product obtained in step (1) and continuing the reaction, thereby grafting the guanidine salt onto the surface of the product obtained in step (1).

[0036] In step (1), the monomer M can be provided in one portion (i.e., the amount of the second portion of the monomer M can be 0) or in two portions (i.e., the amount of the second portion of the monomer M can be greater than 0). The molar ratio of the second portion of the monomer M to the first portion of the monomer M can be (0 to 100):100, for example, 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.

[0037] The ratio of the amounts of maleic anhydride and monomer M can be selected as conventionally. 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 calculated as terminal olefins) can be 50 to 150 moles, more preferably 75 to 100 moles, per 100 moles of maleic anhydride.

[0038] In step (1), the organic solvent can be a solvent commonly used in solution polymerization reactions, particularly self-stabilizing precipitation polymerization reactions, and is preferably selected from organic acid alkyl esters or mixtures of organic acid alkyl esters with alkanes or aromatic hydrocarbons. Examples of organic acid alkyl esters include, but are not limited to, at least one of methyl formate, ethyl formate, propyl formate, butyl formate, isobutyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, amyl acetate, isoamyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, isobutyl butyrate, isoamyl butyrate, isoamyl isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate, and ethyl phenylacetate. Examples of alkanes include, but are not limited to, n-hexane and / or n-heptane. Aromatic hydrocarbons include, but are not limited to, at least one of benzene, toluene, and xylene.

[0039] The amount of organic solvent can be conventionally selected as long as it provides a suitable medium for the reaction in step (1). Preferably, the amount of organic solvent can be 50 to 150 L per 100 moles of maleic anhydride.

[0040] In step (1), the initiator can be provided in one portion (i.e., the amount of the second portion of initiator can be 0) or in two portions (i.e., the amount of the second portion of initiator is greater than 0). The molar ratio of the second portion of initiator to the first portion of initiator can be (0 to 100):100, for example, 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.

[0041] In the method of the present invention, the total amount of the initiator is not particularly limited. Preferably, the total amount of the initiator (the total amount of the first part of the initiator and the second part of the initiator) is 0.05 to 10 mol, preferably 0.5 to 5 mol, more preferably 0.8 to 1.5 mol, relative to 100 mol of maleic anhydride.

[0042] The initiator may be a reagent commonly used in the art to initiate the polymerization reaction of maleic anhydride with an olefin, such as a thermal decomposition initiator. Preferably, the initiator may be at least one selected from the group consisting of dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, dodecanoyl peroxide, tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, azobisisobutyronitrile, and azobisisoheptanenitrile.

[0043] 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 amount of the crosslinking agent used is 1 to 40 moles, preferably 6 to 20 moles, per 100 moles of maleic anhydride.

[0044] The types of crosslinking agents are as described above.

[0045] The crosslinker supply may be in the form of a solution containing the crosslinker, optionally the remaining second portion of the monomer M, and optionally the remaining second portion of the initiator, and optionally a solvent, preferably a solvent. The type and content of the solvent in the crosslinker-containing solution are not particularly limited, as long as the crosslinker, monomer, initiator, and other substances therein are sufficiently dissolved. Typically, the type of solvent in the crosslinker-containing solution can be the same as the organic solvent used in the polymerization reaction, i.e., it can include, for example, an organic acid alkyl ester as described above. The concentration of the crosslinker in the crosslinker-containing solution can be 0.2 to 3 mol / L.

[0046] In step (1), maleic anhydride is first contacted with monomer M to undergo a partial reaction; that is, maleic anhydride and monomer M do not completely react but only partially participate in the polymerization reaction in the presence of the initiator. As a result, the unreacted maleic anhydride and monomer M subsequently react with the crosslinker. The conditions for contacting maleic anhydride with monomer M to undergo the reaction can be conventional, as long as they are controlled so that maleic anhydride and monomer M only partially participate in the polymerization reaction. Preferably, the conditions for contacting maleic anhydride with the first portion of monomer M to undergo the reaction include an inert atmosphere (e.g., nitrogen); a temperature of 50 to 90°C (more preferably 60 to 70°C); a pressure (gauge pressure or relative pressure) of 0.3 to 1 MPa (more preferably 0.4 to 0.5 MPa); and a duration of 0.5 to 4 hours (more preferably 0.5 to 2 hours).

[0047] In step (1), after maleic anhydride is contacted with monomer M to carry out a partial reaction, a feed (preferably a solution) containing a crosslinking agent is introduced to carry out the subsequent reaction, which is particularly beneficial for the formation of a shell crosslinked structure. The conditions for the subsequent reaction can be conventional as long as they allow the various reactants to participate in the reaction as much as possible. Preferably, the conditions for the subsequent reaction include a temperature of 50 to 90°C; a pressure of 0.3 to 1 MPa; and a period of 2 to 15 hours. The temperature and pressure for the subsequent reaction may be the same as or different from the temperature and pressure used for contacting maleic anhydride with monomer M to carry out the reaction. According to a preferred embodiment, the manner of introducing the crosslinking agent-containing solution for the subsequent reaction can be as follows: within 1 to 3 hours, the crosslinking agent-containing solution is added dropwise to the product obtained in step (1) at 50 to 90°C (more preferably 60 to 70°C), and the reaction is continued for another 1 to 4 hours while maintaining the temperature.

[0048] In step (2), a guanidine salt, preferably a solution of a guanidine salt, more preferably an aqueous solution, is added to the product (suspension) obtained in step (1), followed by rapid stirring to allow the reaction to proceed. The amount of guanidine salt used can be selected as conventional, and preferably, per 1,000 g of maleic anhydride, the amount of guanidine salt can be 5 g to 5,000 g, preferably 20 g to 3,000 g, more preferably 100 g to 2,000 g. The concentration of the aqueous guanidine salt solution can be 0.5 to 50 wt %, preferably 1 to 30 wt %, more preferably 1 to 20 wt %. The amount of the aqueous guanidine salt solution can be 500 to 10,000 g, preferably 1,000 to 8,000 g, more preferably 1,000 to 6,000 g, per 1,000 g of maleic anhydride.

[0049] The grafting reaction in step (2) can be carried out under conventional conditions. For example, the grafting reaction conditions include a temperature of 0 to 100°C, preferably 2.5 to 90°C, more preferably 5 to 80°C, and even more preferably 30 to 80°C; a reaction period of 0.5 to 10 hours, preferably 0.5 to 8 hours, and more preferably 0.5 to 6 hours; and a stirring speed of 50 to 1000 rpm, preferably 50 to 500 rpm, and more preferably 100 to 500 rpm.

[0050] In step (2), the product (suspension) obtained in step (1) can be subjected to post-treatment (separation, washing, drying) before the grafting reaction. The product obtained after drying can be added to a solution of a guanidine salt, preferably an aqueous solution, for the reaction. Conventional washing solvents, such as 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 for washing. The concentration of the aqueous solution of the guanidine salt can be 0.5 to 50% by weight, preferably 1 to 30% by weight.

[0051] The final product obtained in step (2) can be further separated to obtain a flame-retardant antibacterial microsphere product grafted with a guanidine salt. For example, the separation can be performed in the following manner: centrifugation, water washing, organic solvent washing (the aforementioned washing solvents can be used, i.e., at least one selected from the group consisting of n-hexane, isohexane, cyclohexane, n-heptane, n-octane, isooctane, methanol, ethanol, propanol, isopropanol, diethyl ether, isopropyl ether, and methyl tert-butyl ether), centrifugation, and drying (e.g., vacuum drying). Unexpectedly, it has been found that in step (2), the suspension obtained in step (1) can be directly subjected to a grafting reaction with a solution of a guanidine salt (preferably an aqueous solution) without a step of removing the organic solvent, and the guanidine salt flame-retardant antibacterial microsphere product of the present invention, i.e., a flame-retardant antibacterial agent, can also be effectively prepared. Therefore, according to a preferred embodiment, in step (2), the product (suspension) obtained in step (1) can be directly reacted with a solution of guanidine salt (one-pot method), thereby obtaining a mixed system containing guanidine salt flame-retardant antibacterial microspheres; the mixed system can be further separated to obtain the guanidine salt flame-retardant antibacterial microsphere product. For example, the separation can be carried out as follows: the mixture is allowed to settle and stratified, in which the organic phase is recycled, and the heavy phase is centrifuged, washed with water, centrifuged, and dried (e.g., dried under reduced pressure) to obtain the guanidine salt flame-retardant antibacterial microspheres. This one-pot method product post-processing only requires one liquid-liquid separation, one solid-liquid separation, washing, and drying, which effectively shortens the time consumption of a single batch, simplifies the process flow, reduces the unit equipment, and effectively reduces energy consumption. This method requires only one organic solvent as the reaction medium; the solvent can be recycled simply by layering and drying; layering can be achieved in the reactor without using special water separation equipment; and the solvent can be recycled without distillation purification, thereby saving energy and reducing consumption and effectively reducing environmental pollution caused by the use of organic solvents.

[0052] In a third aspect, the present invention provides the use of the flame retardant antibacterial agent according to the present invention as an additive in flame retardant antibacterial resin compositions and articles (particularly fibers, films and fabrics, e.g. nonwoven fabrics), for example flame retardant antibacterial thermoplastic resin compositions and articles, particularly articles for schools, hospitals, hotels, smart home appliances, new energy vehicles, etc.

[0053] In a fourth aspect, the present invention provides a flame-retardant antibacterial thermoplastic resin composition comprising a thermoplastic resin as a matrix and the flame-retardant antibacterial agent according to the present invention. The flame-retardant antibacterial agent may be used in an amount of 0.05 to 4.0 parts by weight, preferably 0.1 to 2.8 parts by weight, and more preferably 0.5 to 2 parts by weight, per 100 parts by weight of the thermoplastic resin.

[0054] The thermoplastic resin used as the matrix may be at least one selected from the group consisting 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 selected from the group consisting of alloys and mixtures of thermoplastic resins, preferably at least one selected from the group consisting of polyolefin, particularly polyethylene and polypropylene, and copolymers thereof.

[0055] The flame-retardant antibacterial thermoplastic resin composition preferably further contains an aluminum hypophosphite-based flame retardant and / or a halogen-containing flame retardant. Thus, a synergistic effect can be created between the flame-retardant antibacterial microspheres of the present invention and the aluminum hypophosphite-based flame retardant and / or the halogen-containing flame retardant through the construction of a hybrid carbon layer structure. As a result, the flame-retardant antibacterial properties of the composition are significantly better than those of a composition containing the same amounts of the flame-retardant antibacterial microspheres of the present invention, the aluminum hypophosphite-based flame retardant, or the halogen-containing flame retardant added separately. More preferably, the resin composition simultaneously contains both the aluminum hypophosphite-based flame retardant and the halogen-containing flame retardant. Due to this synergistic effect, the total amount of flame retardant added can be significantly reduced while achieving the same flame-retardant effect.

[0056] The aluminum hypophosphite-based flame retardant can be selected from the group consisting of inorganic aluminum hypophosphite, aluminum alkylphosphinate (e.g., at least one of aluminum diethylphosphinate, aluminum dipropylphosphinate, and aluminum phenylphosphinate), and combinations thereof, preferably inorganic aluminum hypophosphite, aluminum diethylphosphinate, and combinations thereof. The amount of the aluminum hypophosphite-based flame retardant can be 0 to 2.0 parts by weight, preferably 0.1 to 1.2 parts by weight, and more preferably 0.1 to 0.6 parts by weight, per 100 parts by weight of the thermoplastic resin. The halogen-containing flame retardant is preferably melamine hydrohalide, more preferably melamine hydrobromide (MHB). The amount of the halogen-containing flame retardant can be 0 to 2.0 parts by weight, preferably 0.1 to 1.2 parts by weight, and more preferably 0.1 to 0.8 parts by weight, per 100 parts by weight of the thermoplastic resin.

[0057] The flame-retardant, antibacterial thermoplastic resin composition preferably further comprises a flame-retardant synergist and / or an antifungal agent. The addition of the flame-retardant synergist can further improve the flame-retardant efficiency, and the addition of the antifungal agent can further improve the antibacterial efficiency, so that the total amount of the flame retardant or antibacterial agent can be reduced while achieving the same flame-retardant or antibacterial effect.

[0058] The flame retardant synergist may be selected from the group consisting of 2,3-dimethyl-2,3-diphenylbutane (DMDPB, abbreviated as "Bicumyl"), paracumene polymer (polybicumyl), and combinations thereof. The amount of the flame retardant synergist may be 0 to 1.0 part by weight, preferably 0.05 to 1 part by weight, and more preferably 0.05 to 0.6 parts by weight, relative to 100 parts by weight of the thermoplastic resin.

[0059] The antifungal agent may be at least one selected from the group consisting of pyrithione, isothiazolinone, 10,10'-oxybisphenoxarsine (OBPA), 3-iodo-2-propynyl-butyl-carbamate (IPBC), 2,4,4'-trichloro-2'-hydroxydiphenyl ether (triclosan), 2-(thiazol-4-yl)benzimidazole (thiabendazole), etc., which have good antifungal effects. The pyrithione may be at least one selected from the group consisting of zinc pyrithione, copper pyrithione, bispyrithione, etc. The isothiazolinone may be, for example, at least one selected from the group consisting of 2-methyl-1-isothiazolin-3-one (MIT), 5-chloro-2-methyl-1-isothiazolin-3-one (CMIT), 2-n-octyl-4-isothiazolin-3-one (OIT), 4,5-dichloro-2-n-octyl-3-isothiazolinone (DCOIT), 1,2-benzisothiazolin-3-one (BIT), 4-methyl-1,2-benzisothiazolin-3-one (MBIT), 4-n-butyl-1,2-benzisothiazolin-3-one (BBIT), and the like.

[0060] The antifungal agent can be used in an amount of 0 to 5.0 parts by weight, preferably 0.05 to 4.0 parts by weight, and more preferably 0.1 to 3.6 parts by weight, relative to 100 parts by weight of the thermoplastic resin.

[0061] For example, the flame retardant antimicrobial thermoplastic resin composition may include the following ingredients per 100 parts by weight of thermoplastic resin: 0.05 to 4.0 parts by weight, preferably 0.1 to 2.8 parts by weight, more preferably 0.5 to 2 parts by weight of the flame-retardant antibacterial agent according to the present invention; 0 to 2.0 parts by weight, preferably 0.1 to 1.2 parts by weight, more preferably 0.1 to 0.6 parts by weight of an aluminum hypophosphite-based flame retardant; 0 to 2.0 parts by weight, preferably 0.1 to 1.2 parts by weight, more preferably 0.1 to 0.8 parts by weight of melamine hydrobromide; 0 to 1.0 parts by weight, preferably 0.05 to 1 part by weight, more preferably 0.05 to 0.6 parts by weight of a flame retardant synergist; and 0 to 5.0 parts by weight, preferably 0.05 to 4.0 parts by weight, more preferably 0.1 to 3.6 parts by weight of an antifungal agent.

[0062] Furthermore, the flame-retardant antibacterial thermoplastic resin composition of the present invention may further contain other functional additives as needed, including, but not limited to, at least one of antioxidants, light stabilizers, toughening agents, compatibilizers, pigments, dispersants, etc. The amount of other functional additives may be 0.1 to 100 parts by weight per 100 parts by weight of the thermoplastic resin, and the specific amount may be adjusted as needed.

[0063] The present invention further provides a method for preparing a flame retardant antimicrobial thermoplastic resin composition, comprising melt blending components comprising a thermoplastic resin and an antimicrobial flame retardant, and specifically the method may comprise the steps of: a. A step of uniformly mixing a component containing a thermoplastic resin and the antibacterial flame retardant according to the present invention, and optionally a component containing an aluminum hypophosphite-based flame retardant, a halogen-containing flame retardant (preferably melamine hydrobromide), a flame retardant synergist, and an antifungal agent, using, for example, a high-speed mixer; b. A step in which the mixed pre-mixture in step a is extruded, pelletized, and further dried using tools and equipment commonly used in the art, such as a twin-screw extrusion pelletizer, to obtain pellets of the flame-retardant antibacterial thermoplastic resin composition.

[0064] In a fifth aspect of the present invention, the present invention also provides articles prepared from the flame-retardant antimicrobial thermoplastic resin composition of the present invention, particularly in the form of fibers, films and fabrics, such as nonwoven fabrics, which are particularly useful in schools, hospitals, hotels, smart home appliances, new energy vehicles and other fields.

[0065] The flame-retardant antibacterial agent of the present invention (i.e., guanidine salt flame-retardant antibacterial microspheres) has both good flame retardant and antibacterial effects, making it an effective single-component flame-retardant antibacterial multifunctional additive. Compared with the current method of adding flame retardants and antibacterial agents separately, the guanidine salt microspheres are easy to disperse in a thermoplastic resin matrix, thereby effectively improving the flame retardant and antibacterial efficiencies.

[0066] At the same time, the guanidine salt flame-retardant antibacterial microspheres have good fluidity and low moisture absorption, do not adhere to the wall during the preparation of the flame-retardant antibacterial thermoplastic resin composition, are easy to remove, and the manufacturing operation is simple and does not require excessive control of the manufacturing conditions.

[0067] Since the microspheres contain maleic anhydride structural units, the compatibility of the microspheres with the matrix resin can be significantly improved, particularly when the microspheres contain a crosslinked alternating copolymer structure formed by maleic anhydride, a C4-C9 aliphatic olefin, and a crosslinking agent, and the dispersion of the microspheres in the matrix resin can be improved, thereby further improving the antibacterial and flame retardant effects and efficiency, or even eliminating the need for a compatibilizer, thereby avoiding the adverse effects of the compatibilizer on the flame retardant and antibacterial effects.

[0068] When the microspheres are prepared by the self-stabilizing precipitation polymerization method, the obtained microspheres are uniform and regular in morphology and size, and exhibit better dispersion in the matrix resin, and can achieve better and more uniform distribution of the grafted guanidine salt in the matrix resin, thereby obtaining better flame retardant and antibacterial effects and efficiency; furthermore, the obtained microspheres have controllable structure and adjustable particle size, making the manufacturing process simpler and more controllable.

[0069] The microspheres can be prepared by using C4 and C5 fractions from oil refining or the ethylene industry as monomers, especially C4 and C5 fractions as ethylene cracking products in the petrochemical industry, which provides a new method for utilizing mixed olefin resources in the petrochemical industry and contributes to improving the added value of its products.

[0070] The flame retardant antimicrobial agents of the present invention also expand the technological reserves for meeting fire safety and antimicrobial requirements.

[0071] Furthermore, the flame-retardant antibacterial thermoplastic resin composition containing the low-property antibacterial agent of the present invention simultaneously has good flame retardancy and antibacterial properties, and also has good antifungal effect. In addition, it can have good water resistance, particularly when microspheres having a shell crosslinked structure are used.

[0072] The flame-retardant antibacterial agent of the present invention is an efficient, multifunctional, single-component flame-retardant antibacterial microsphere, allowing for the preparation of flame-retardant antibacterial thermoplastic resin compositions with low additive amounts. Both the flame-retardant and antibacterial efficiencies of the additive are improved, allowing for a reduction in the additive amount. At the same time, dispersion performance is improved. Therefore, the prepared thermoplastic resin compositions have excellent overall performance.

[0073] [Example] The present invention will be further described below in conjunction with the following examples, but is not limited by these examples.

[0074] 1) Source of starting material Polyethylene (PE): Brand 7042, Maoming Petrochemical, China Polypropylene (PP): GD-H-230, Cangzhou Refining & Chemical, China Nylon 6: Brand B3S, BASF PC: Polycarbonate, Brand 3103, Bayer ABS: Acrylonitrile / Butadiene / Styrene Copolymer, Brand 3504, Shanghai Gaoqiao, China Polyhexamethylene guanidine phosphate: Foshan Lanfeng Additives, China Guanidine dihydrogen phosphate: Beshine (Beijing) Chemical Technology Co., Ltd., China Guanidine hydrobromide: SHANGHAI ZZBIO CO., LTD, China Aminoguanidine nitrate: Guangdong Wengjiang Chemical, China Bikmil: Guangzhou Xijia Chemical, China Melamine hydrobromide: Guangzhou Xijia Chemical, China Aluminum hypophosphite: Guangzhou Xijia Chemical, China Zinc pyrithione, copper pyrithione: Zhufeng Fine Chemical Co., Ltd., China Composite antioxidant: obtained by uniformly mixing antioxidant 1010 (BASF), antioxidant 168 (BASF), and calcium stearate (Shandong Hao Na, China) in a mass ratio of 2 / 2 / 1. Silver-loaded zeolite antibacterial agent: Xi'an Conval Antibacterial Technology Co., Ltd., China 2) Test methods and equipment Average particle size of the microspheres: They were characterized by the number average particle size measured by a Hitachi S-4800 scanning electron microscope (Japan).

[0075] Tensile strength: Measured according to standard GB / T1040-2006.

[0076] Flexural modulus: Measured according to standard GB / T9341-2008.

[0077] Antibacterial testing was performed in accordance with standard GB / T31402-2015. Specifically, the antibacterial testing method employed a film application method, with the following steps: After sterilization, a bacterial suspension was inoculated onto the surface of the test sample, which was then covered with a polyethylene film to form a uniform liquid film between the sample and the film. After incubation under specific conditions, the sample was eluted and then diluted to an appropriate concentration gradient. A specific amount was then collected, spread on a medium, and re-incubated. The viable cell count was measured to calculate the antibacterial rate.

[0078] Vertical Burning Test (UL-94): Tested according to standard GN / T2408-2008. The flammability of the specimens was tested using a CZF-2 vertical burning tester (Shangyuan Instruments, Nanjing, China). The specimens were rod-shaped specimens measuring 120 mm x 10 mm x 10 mm. The specific evaluation criteria for the UL-94 test are as follows:

[0079] [Table 1]

[0080] HB Level: Minimum flame retardancy level under the UL-94 standard. Requirements include a burn rate of less than 40 mm / min for specimens 3-13 mm thick; a burn rate of less than 70 mm / min for specimens less than 3 mm thick; or burning cessation before reaching the 100 mm reference mark.

[0081] If the specimen does not reach the HB level, it is reported as not rated (NR).

[0082] Limiting oxygen index (LOI value) experiment: Tested according to standard GB / T2406.1-2008.

[0083] Glow-wire flammability index experiment: Tested according to standard GB / T5961.11-2006.

[0084] Crosslinking degree: The crosslinking degree of the microspheres was measured by solvent extraction and characterized by the gel content. The specific method is as follows: After weighing the test sample (W1), the test sample was placed in acetone in an amount five times its own weight and extracted at 50°C for 30 minutes. After the extraction was completed, the sample was dried and weighed (W2). The crosslinking degree was calculated as W2 / W1 × 100%. The content of eluted substances was calculated as (1-W2 / W1) × 100%.

[0085] 1. Preparation of guanidine salt flame-retardant antibacterial microspheres (flame-retardant antibacterial agents) Example 1 (1) A C4 fraction obtained from an ethylene cracking process at Sinopec Zhenhai Refining & Chemical (China) was used. The C4 fraction was a mixed butene gas with the following composition: 40.83 wt% trans-2-butene, 18.18 wt% cis-2-butene, 24.29 wt% n-butane, 9.52 wt% n-butene, 2.78 wt% isobutene, and 4.4 wt% others. In an autoclave, 100 g of maleic anhydride and 2 g of azobisisobutyronitrile were dissolved in 800 mL of isoamyl acetate to form Solution 1, and an appropriately weighed amount of mixed butenes (where the molar ratio of maleic anhydride to the active component (terminal olefin) in the mixed olefins was 1:1) was passed through the solution. The reaction was carried out under a nitrogen atmosphere at 70°C and 0.5 MPa for 1 hour.

[0086] (2) 25 g of divinylbenzene was dissolved in 200 mL of isoamyl acetate to prepare solution 2. Solution 2 was added dropwise to the reaction system obtained in (1) over 2 hours using a plunger pump. After the addition was completed, the reaction system was allowed to continue reacting for 3 hours while maintaining the temperature.

[0087] (3) After the reaction, the autoclave was depressurized, and 200 g of an aqueous solution of guanidine dihydrogen phosphate (15 wt%) and 200 g of an aqueous solution of polyhexamethylene biguanide hydrochloride (15 wt%) were added and reacted at 80°C for 3 hours. The reaction mixture was allowed to stand to form layers. The heavy phase was centrifuged at 5000 rad / min for 20 minutes. The resulting solid was washed with 4 L of water while stirring and centrifuged at 5000 rad / min for 20 minutes. The resulting solid was again washed with 4 L of water while stirring and centrifuged at 5000 rad / min for 20 minutes. The resulting solid was dried under vacuum to obtain a flame-retardant antibacterial agent, i.e., polymer microspheres #1 with guanidine salt grafted onto the surface. The average particle size of the resulting polymer microspheres was 1280 nm. After soaking the resulting polymer microspheres in acetone in an amount five times the weight of the polymer microspheres at 50°C for 30 minutes, the weight percentage of the material eluted from the polymer microspheres was 5.5%, and the corresponding degree of crosslinking was 94.5%.

[0088] Example 2 The system after the reaction in step (2) was centrifuged at 5000 rad / min for 30 minutes to obtain cross-linked mixed butene / maleic anhydride polymer microspheres, which were then purified by washing with n-hexane and dried under vacuum, except that a flame-retardant antibacterial agent was prepared in the same manner as in Example 1. Next, the dried cross-linked mixed butene / maleic anhydride polymer microspheres were added to 400 g of a mixed aqueous solution of guanidine dihydrogen phosphate (20 wt%) and polyhexamethylene biguanide hydrochloride (20 wt%), and the mixture was reacted at 80°C for 3 hours. The reaction mixture was centrifuged at 5000 rad / min for 20 minutes, and the resulting solid was washed with 4 L of water while stirring and centrifuged at 5000 rad / min for 20 minutes. The resulting solid was washed with 4 L of water while stirring and centrifuged at 5000 rad / min for 20 minutes. The resulting solid was then dried under vacuum to obtain the flame-retardant antibacterial agent, i.e., polymer microspheres #2 with guanidine salt grafted onto their surfaces. The average particle size of the resulting polymer microspheres was 1310 nm. After soaking the resulting polymer microspheres in acetone in an amount five times their weight at 50°C for 30 minutes, the weight percentage of the material eluted from the polymer microspheres was 5.6%, corresponding to a crosslinking degree of 94.4%.

[0089] Example 3 (1) In an autoclave, 100 g of maleic anhydride and 2 g of azobisisobutyronitrile were dissolved in 800 mL of isoamyl acetate to form Solution 1, and an appropriately weighed amount of mixed butenes (the composition was the same as in Example 1, and the molar ratio of maleic anhydride to the active ingredient (terminal olefin) in the mixed olefins was 1:1) was passed through the solution. The reaction was carried out under a nitrogen atmosphere at 70°C and 0.4 MPa for 2 hours.

[0090] (2) 15 g of divinylbenzene was dissolved in 200 mL of isoamyl acetate to prepare Solution 2. Solution 2 was added dropwise to the reaction system over 2 hours using a plunger pump. After the addition was complete, the reaction system was allowed to continue reacting for 3 hours while maintaining the temperature.

[0091] (3) After the reaction, the autoclave was depressurized, and 200 g of an aqueous solution of guanidine hydrobromide (20 wt%) and 200 g of an aqueous solution of polyhexamethyleneguanidine phosphate (20 wt%) were added separately and reacted at 60°C for 7 hours. The reaction mixture was allowed to stand to form layers. The heavy phase was centrifuged at 5000 rad / min for 20 minutes. The resulting solid was washed with 4 L of water while stirring and centrifuged at 5000 rad / min for 20 minutes. The resulting solid was again washed with 4 L of water while stirring and centrifuged at 5000 rad / min for 20 minutes. The resulting solid was dried under vacuum to obtain a flame-retardant antibacterial agent, i.e., polymer microspheres #3 with guanidine salt grafted onto their surfaces. The average particle size of the resulting polymer microspheres was 1210 nm. After soaking the resulting polymer microspheres in acetone in an amount five times the weight of the polymer microspheres at 50°C for 30 minutes, the weight percentage of the material eluted from the polymer microspheres was 6.5%, and the corresponding degree of crosslinking was 93.5%.

[0092] Example 4 (1) In an autoclave, 100 g of maleic anhydride and 1.5 g of azobisisobutyronitrile were dissolved in 800 mL of isoamyl acetate to form Solution 1, and an appropriately weighed amount of mixed butenes (the composition of which was the same as in Example 1, and the molar ratio of maleic anhydride to the active component (terminal olefin) in the mixed olefins was 1:0.75) was passed through the solution. The reaction was carried out under a nitrogen atmosphere at 70°C and 0.5 MPa for 1 hour.

[0093] (2) 0.5 g of azobisisobutyronitrile and 18 g of divinylbenzene were dissolved in 200 mL of isoamyl acetate to prepare Solution 2. Solution 2 was added dropwise to the reaction system using a plunger pump over 2 hours. After the addition was complete, the reaction system was allowed to continue reacting for 3 hours while maintaining the temperature.

[0094] (3) After the reaction, the autoclave was depressurized, and 200 g of an aqueous solution of guanidine dihydrogen phosphate (20 wt%), 200 g of an aqueous solution of guanidine hydrobromide (20 wt%), and 200 g of an aqueous solution of polyhexamethyleneguanidine phosphate (20 wt%) were added separately and reacted at 60°C for 10 hours. The reaction mixture was allowed to stand to form layers. The heavy phase was centrifuged at 5000 rad / min for 20 minutes. The resulting solid was washed with 4 L of water while stirring and centrifuged at 5000 rad / min for 20 minutes. The resulting solid was again washed with 4 L of water while stirring and centrifuged at 5000 rad / min for 20 minutes. The resulting solid was dried under vacuum to obtain a flame-retardant antibacterial agent, i.e., polymer microspheres #4 with guanidine salt grafted onto the surface. The average particle size of the resulting polymer microspheres was 1510 nm. After soaking the resulting polymer microspheres in acetone in an amount five times the weight of the polymer microspheres at 50°C for 30 minutes, the weight percentage of the material eluted from the polymer microspheres was 5.8%, and the corresponding degree of crosslinking was 94.2%.

[0095] Example 5 (1) The C5 fraction obtained from the ethylene cracking process of Sinopec Zhenhai Refining & Chemical (China) was used. The C5 fraction mixture had the following composition: 47.83 wt% diolefins (isoprene, cyclopentadiene, 1,4-pentadiene, piperylene), 13.18 wt% monoolefins (1-pentene, 2-pentene, cyclopentene, 2-methyl-1-butene, 2-methyl-2-butene), 21.29 wt% alkanes (n-pentane, isopentane, cyclopentane, 2-methylbutane), 0.92 wt% alkynes (but-2-yne, 3-penten-1-yne), and 16.78 wt% others. In an autoclave, 100 g of maleic anhydride and 2 g of azobisisobutyronitrile were dissolved in 800 mL of isoamyl acetate to form solution 1, and an appropriately weighed amount of mixed C5 (wherein the molar ratio of maleic anhydride to the active ingredient (terminal olefin) in the mixed olefin was 1:0.5) was passed through it. The reaction was carried out under a nitrogen atmosphere at 70°C and 0.5 MPa for 1 hour.

[0096] (2) A properly weighed amount of mixed C5 fraction (wherein the molar ratio of maleic anhydride to the active ingredients (terminal olefins including diolefins) in a portion of the mixed olefins was 1:0.5) and 15 g of divinylbenzene were dissolved in 200 mL of isoamyl acetate to prepare Solution 2, which was added dropwise to the reaction system over 2 hours using a plunger pump. After the addition was completed, the reaction system was allowed to continue for 3 hours while maintaining the temperature.

[0097] (3) After the reaction, the autoclave was depressurized and allowed to stand to stratify the system, where the heavy phase was centrifuged at 5000 rad / min for 20 minutes in a centrifuge, and the resulting solid was washed with 400 mL of water while stirring and centrifuged at 5000 rad / min for 20 minutes in a centrifuge; the resulting solid was again washed with 400 mL of water while stirring and centrifuged at 5000 rad / min for 20 minutes in a centrifuge; the resulting solid was dried under vacuum to obtain crosslinked mixed pentene / maleic anhydride polymer microspheres.

[0098] (4) 100 g of cross-linked mixed pentene / maleic anhydride polymer microspheres were added to 400 g of a mixed solution of aminoguanidine nitrate (15 wt%) and polyhexamethylene biguanide phosphate (15 wt%) and reacted at 50°C for 6 hours. The reaction mixture was centrifuged at 5000 rad / min for 20 minutes. The resulting solid was washed with 4 L of water while stirring and centrifuged at 5000 rad / min for 20 minutes. The resulting solid was washed again with 4 L of water while stirring and centrifuged at 5000 rad / min for 20 minutes. The resulting solid was dried under vacuum to obtain a flame-retardant antibacterial agent, i.e., polymer microspheres #5 with guanidine salt grafted onto the surface. The average particle size of the resulting polymer microspheres was 1458 nm. After soaking the resulting polymer microspheres in acetone in an amount five times the weight of the polymer microspheres at 50°C for 30 minutes, the weight percentage of the material eluted from the polymer microspheres was 5.6%, and the corresponding degree of crosslinking was 94.4%.

[0099] Example 6 A flame-retardant antibacterial agent was prepared in the same manner as in Example 5, except that the amount of divinylbenzene in step (2) was changed to 10 g, and polymer microspheres #6 were finally obtained. The average particle size of the obtained polymer microspheres was 1200 nm. When the obtained polymer microspheres were soaked in acetone in an amount five times the weight of the polymer microspheres at 50°C for 30 minutes, the weight percentage of the substance eluted from the polymer microspheres was 7.0%, and the corresponding degree of crosslinking was 93.0%.

[0100] Example 7 A flame-retardant antibacterial agent was prepared in the same manner as in Example 1, except that divinylbenzene in step (1) was replaced with 36.0 g of pentaerythritol tetraacrylate, ultimately yielding polymer microspheres #7. The average particle size of the resulting polymer microspheres was 1320 nm. When the resulting polymer microspheres were soaked in acetone in an amount five times their weight at 50°C for 30 minutes, the weight percentage of the substance eluted from the polymer microspheres was 5.2%, and the corresponding degree of crosslinking was 94.8%.

[0101] 2. Preparation and property comparison of flame-retardant antibacterial thermoplastic resin composition and comparative resin composition The formulations of the resin compositions used in the examples and comparative examples are shown in Table 1, and all amounts in Table 1 are in parts by weight. The properties of the resin compositions prepared in the examples and comparative examples are shown in Table 2.

[0102] Example 8 100 parts by weight of polypropylene, 1.0 part by weight of polymer microspheres #1, 0.2 parts by weight of aluminum hypophosphite, 0.35 parts by weight of MHB (melamine hydrobromide), 0.1 part by weight of flame retardant synergist DMDPB (Bicumyl), 0.2 parts by weight of zinc pyrithione, and 0.25 parts by weight of a complex antioxidant were charged into a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200°C to 220°C for flame retardancy, antibacterial properties, and mechanical property testing.

[0103] Comparative Example 1 100 parts by weight of polypropylene and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and thoroughly and uniformly mixed. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) and a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard splines of specified sizes at injection molding temperatures of 200°C to 220°C for flame retardancy, antibacterial properties, and mechanical property testing.

[0104] Comparative Example 2 100 parts by weight of polypropylene, 1.0 part by weight of silver-loaded zeolite antibacterial agent, 0.2 parts by weight of aluminum hypophosphite, 0.35 parts by weight of MHB, 0.1 part by weight of flame-retardant synergist DMDPB, 0.2 parts by weight of zinc pyrithione, and 0.25 parts by weight of a complex antioxidant were mixed thoroughly and uniformly in a high-speed mixer. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200°C to 220°C for flame-retardant, antibacterial, and mechanical property testing.

[0105] Example 9 100 parts by weight of polypropylene, 1.0 part by weight of polymer microspheres #2, 0.2 parts by weight of aluminum hypophosphite, 0.35 parts by weight of MHB, 0.1 parts by weight of the flame retardant synergist DMDPB, 0.2 parts by weight of zinc pyrithione, and 0.25 parts by weight of a complex antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200°C to 220°C for flame retardancy, antibacterial properties, and mechanical property testing.

[0106] Example 10 100 parts by weight of polypropylene, 0.9 parts by weight of polymer microspheres #3, 0.25 parts by weight of aluminum hypophosphite, 0.2 parts by weight of MHB, 0.1 parts by weight of DMDPB, 0.2 parts by weight of zinc pyrithione, and 0.25 parts by weight of a complex antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200°C to 220°C for flame retardancy, antibacterial properties, and mechanical property testing.

[0107] Example 11 100 parts by weight of polypropylene, 1.6 parts by weight of polymer microspheres #4, 0.1 parts by weight of DMDPB, 0.2 parts by weight of zinc pyrithione, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200°C to 220°C for flame retardancy, antibacterial properties, and mechanical property testing.

[0108] Comparative Example 3 100 parts by weight of polypropylene, 1.6 parts by weight of silver-loaded zeolite antibacterial agent, 0.1 part by weight of DMDPB, 0.2 part by weight of zinc pyrithione, and 0.25 parts by weight of a composite antioxidant were mixed thoroughly and uniformly in a high-speed mixer. After thorough and uniform mixing, the mixture was melt-blended and extruded into pellets in a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200°C to 220°C for flame retardancy, antibacterial properties, and mechanical property testing.

[0109] Example 12 100 parts by weight of polypropylene, 1.0 part by weight of polymer microspheres #5, 0.25 parts by weight of aluminum hypophosphite, 0.3 parts by weight of MHB, 0.1 parts by weight of DMDPB, 0.2 parts by weight of zinc pyrithione, and 0.25 parts by weight of a complex antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200°C to 220°C for flame retardancy, antibacterial properties, and mechanical property testing.

[0110] Example 13 100 parts by weight of polypropylene, 1.0 part by weight of polymer microspheres #6, 0.25 parts by weight of aluminum hypophosphite, 0.3 parts by weight of MHB, 0.1 parts by weight of DMDPB, 0.2 parts by weight of zinc pyrithione, and 0.25 parts by weight of a complex antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into a standard spline at an injection molding temperature of 200°C to 220°C for flame retardancy, antibacterial properties, and mechanical property testing.

[0111] Example 14 100 parts by weight of polypropylene, 1.2 parts by weight of polymer microspheres #7, 0.2 parts by weight of aluminum hypophosphite, 0.3 parts by weight of MHB, 0.1 parts by weight of DMDPB, 0.2 parts by weight of zinc pyrithione, and 0.25 parts by weight of a complex antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into a standard spline at an injection molding temperature of 200°C to 220°C for flame retardancy, antibacterial properties, and mechanical property testing.

[0112] Example 15 100 parts by weight of polyethylene, 2 parts by weight of polymer microspheres #1, 0.2 parts by weight of zinc pyrithione, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at extruder temperatures of 175°C to 205°C (175°C, 190°C, 205°C, 205°C, 200°C, and 195°C) and a rotation speed of 350 rpm, extruded, and pelletized. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into samples for flame retardancy and antibacterial testing at injection molding temperatures of 190°C to 200°C.

[0113] Comparative Example 4 100 parts by weight of polyethylene and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at temperatures ranging from 175°C to 205°C (175°C, 190°C, 205°C, 205°C, 200°C, and 195°C) and a rotation speed of 350 rpm, extruded, and pelletized. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into samples for flame retardancy and antibacterial testing at injection molding temperatures ranging from 190°C to 200°C.

[0114] Example 16 100 parts by weight of nylon 6, 2.5 parts by weight of polymer microspheres #2, 0.3 parts by weight of zinc pyrithione, and 0.3 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at extruder temperatures of 220°C to 240°C (220°C, 230°C, 240°C, 240°C, and 240°C) and a rotation speed of 350 rpm, extruded, and pelletized. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into samples for flame retardancy and antibacterial testing at injection molding temperatures of 230°C to 240°C.

[0115] Comparative Example 5 100 parts by weight of nylon 6 and 0.3 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. The resulting mixture was melt-blended, extruded, and pelletized in a twin-screw extruder at an extruder temperature of 220°C to 240°C (various zone temperatures: 220°C, 230°C, 240°C, 240°C, and 240°C) and a rotation speed of 350 rpm. The extruded pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded at an injection molding temperature of 230°C to 240°C into samples for flame retardancy and antibacterial testing.

[0116] Example 17 80 parts by weight of PC, 20 parts by weight of ABS, 4 parts by weight of polymer microspheres #4, 0.3 parts by weight of zinc pyrithione, and 0.3 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded into pellets in a twin-screw extruder at an extruder temperature of 230°C to 260°C (various zone temperatures: 230°C, 240°C, 255°C, 260°C, 255°C, and 240°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into samples for flame retardancy and antibacterial testing at an injection molding temperature of 230°C to 240°C.

[0117] Comparative Example 6 80 parts by weight of PC, 20 parts by weight of ABS, and 0.3 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at an extruder temperature of 230°C to 260°C (various zone temperatures: 230°C, 240°C, 255°C, 260°C, 255°C, and 240°C) and a rotation speed of 350 rpm, extruded, and pelletized. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into samples for flame retardancy and antibacterial testing at an injection molding temperature of 230°C to 240°C.

[0118] Example 18 100 parts by weight of polypropylene, 1.6 parts by weight of polymer microspheres #4, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at various zone temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C, and a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial properties testing.

[0119] Example 19 100 parts by weight of polypropylene, 5 parts by weight of polymer microspheres #4, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C in various zones at a rotation speed of 350 rpm, extruded, and pelletized. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into samples for flame retardancy and antibacterial testing at injection molding temperatures of 200-220°C.

[0120] Comparative Example 7 1.(1) A C4 fraction obtained from an ethylene cracking process at Sinopec Zhenhai Refining & Chemical (China) was used. The C4 fraction was a mixed butene gas with the following composition: trans-2-butene 40.83 wt%; cis-2-butene 18.18 wt%; n-butane 24.29 wt%; n-butene 9.52 wt%; isobutene 2.78 wt%; and others 4.4 wt%. In an autoclave, 100 g of maleic anhydride and 2 g of azobisisobutyronitrile were dissolved in 800 mL of isoamyl acetate to form Solution 1, and an appropriately weighed amount of mixed butene (wherein the molar ratio of maleic anhydride to the active component (terminal olefin) in the mixed olefin was 1:1) was passed through the solution. The reaction was carried out under a nitrogen atmosphere at 70°C and 0.5 MPa for 1 hour.

[0121] (2) 25 g of divinylbenzene was dissolved in 200 mL of isoamyl acetate to prepare solution 2. Solution 2 was added dropwise to the reaction system obtained in (1) over 2 hours using a plunger pump. After the addition was completed, the reaction system was allowed to continue reacting for 3 hours while maintaining the temperature.

[0122] (3) After the reaction, the autoclave was depressurized and the system was allowed to stand to form layers. The heavy phase was centrifuged at 5000 rad / min for 20 minutes, and the resulting solid was dried under vacuum to obtain polymer microspheres #8 without guanidine salt grafted onto the surface. The average particle size of the resulting polymer microspheres was 1200 nm. When the resulting polymer microspheres were soaked in acetone in an amount five times their weight at 50°C for 30 minutes, the weight percentage of the material eluted from the polymer microspheres was 5.5%, corresponding to a degree of crosslinking of 94.5%.

[0123] 2. 100 parts by weight of polypropylene, 5 parts by weight of polymer microspheres #8, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After mixing, the mixture was melt-blended through a twin-screw extruder at temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C in various zones at a rotation speed of 350 rpm, extruded, and pelletized. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard splines of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial testing.

[0124] Example 20 100 parts by weight of polypropylene, 1 part by weight of polymer microspheres #4, 0.2 parts by weight of aluminum hypophosphite, 0.1 parts by weight of DMDPB, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at various zone temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C, and a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial properties testing.

[0125] Example 21 100 parts by weight of polypropylene, 1 part by weight of polymer microspheres #4, 0.2 parts by weight of aluminum hypophosphite, 0.1 parts by weight of DMDPB, 0.2 parts by weight of zinc pyrithione, and 0.25 parts by weight of a complex antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at various zone temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial properties testing.

[0126] Example 22 100 parts by weight of polypropylene, 1 part by weight of polymer microspheres #4, 0.2 parts by weight of MHB, 0.1 parts by weight of DMDPB, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at various zone temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C, and a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial properties testing.

[0127] Example 23 100 parts by weight of polypropylene, 1.6 parts by weight of polymer microspheres #4, 0.2 parts by weight of aluminum hypophosphite, 0.1 part by weight of DMDPB, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at various zone temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial properties testing.

[0128] Example 24 100 parts by weight of polypropylene, 1.8 parts by weight of polymer microspheres #4, 0.1 part by weight of DMDPB, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C in various zones at a rotation speed of 350 rpm, extruded, and pelletized. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial properties testing.

[0129] Comparative Example 8 100 parts by weight of polypropylene, 1.8 parts by weight of aluminum hypophosphite, 0.1 part by weight of DMDPB, and 0.25 parts by weight of a composite antioxidant were charged into a high-speed mixer and thoroughly and uniformly mixed. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at various zone temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C, and a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial properties testing.

[0130] Example 25 100 parts by weight of polypropylene, 1 part by weight of polymer microspheres #4, 0.1 parts by weight of aluminum hypophosphite, 0.1 parts by weight of MHB, 0.1 parts by weight of DMDPB, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at various zone temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial properties testing.

[0131] Comparative Example 9 100 parts by weight of polypropylene, 1.8 parts by weight of MHB, 0.1 part by weight of DMDPB, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at various zone temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C, and a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial properties testing.

[0132] Example 26 100 parts by weight of polypropylene, 1.6 parts by weight of polymer microspheres #4, 0.2 parts by weight of MHB, 0.1 part by weight of DMDPB, and 0.25 parts by weight of a composite antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended through a twin-screw extruder at various zone temperatures of 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C, and a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200-220°C for flame retardancy and antibacterial properties testing.

[0133] Comparative Example 10 100 parts by weight of polypropylene, 0.2 parts by weight of aluminum hypophosphite, 0.35 parts by weight of MHB, 0.1 parts by weight of the flame-retardant synergist DMDPB, and 0.25 parts by weight of a complex antioxidant were added to a high-speed mixer and mixed thoroughly and uniformly. After thorough and uniform mixing, the mixture was melt-blended and extruded through a twin-screw extruder at an extruder temperature of 190°C to 220°C (various zone temperatures: 190°C, 210°C, 220°C, 220°C, 215°C, and 210°C) at a rotation speed of 350 rpm. The resulting pellets were dried in a thermostatic oven at 90°C for 3 hours and then injection-molded into standard spline molds of specified sizes at injection molding temperatures of 200°C to 220°C for flame retardancy, antibacterial properties, and mechanical property testing.

[0134] [Table 2]

[0135] JPEG0007729815000003.jpg108169

[0136] JPEG0007729815000004.jpg31169

[0137] [Table 3]

[0138] JPEG0007729815000006.jpg58169

[0139] The test results in Tables 1 and 2 show that PP resin itself is highly flammable and does not have antibacterial properties.

[0140] Examples 8-14 and 18-26 are flame-retardant antibacterial PP compositions of the present invention that use the flame-retardant antibacterial microspheres of the present invention. Table 2 shows that the PP compositions of the present invention not only have excellent antibacterial properties, but also achieve HB level and even UL-94 V-2 level with a small amount of flame retardant added, demonstrating good self-extinguishing properties. In Examples 8-14, the compositions were tested and passed the glow-wire flammability index test at 750°C.

[0141] Furthermore, the test results of Examples 8 to 14 show that the PP compositions of the present invention not only have flame retardant and antibacterial properties, but also have improved tensile strength and / or flexural modulus compared to PP alone (Comparative Example 1), thereby overcoming the technical drawback of the prior art, which is the deterioration of the comprehensive performance of the material due to the insufficient dispersion of the flame retardant and antibacterial agent in the matrix.

[0142] Comparisons between Example 11 and Comparative Example 3, between Example 24 and Comparative Examples 8 and 9, and between Example 8 and Comparative Example 2 show that, at the same loading amounts of flame retardant and antibacterial additive, the composition using the flame-retardant antibacterial microspheres of the present invention has better overall flame retardant and antibacterial performance than the prior art compositions using an antibacterial agent alone, a flame retardant alone, or a combination of a flame retardant and an antibacterial agent.

[0143] Comparison between Example 23, Example 24, and Comparative Example 8, or comparison between Example 24, Example 26, and Comparative Example 9, shows that when the flame-retardant antibacterial microspheres of the present invention are used in combination with an aluminum hypophosphite-based flame retardant or a halogen-containing flame retardant, a synergistic effect is created by constructing a hybrid carbon layer structure, and the resulting flame-retardant and antibacterial properties are significantly better than when a single component is used in the same amount.

[0144] A comparison of Examples 20, 22, and 25 shows that when an aluminum hypophosphite-based flame retardant and a halogen-containing flame retardant are added simultaneously, a more synergistic flame retardant effect is obtained compared to when the aluminum hypophosphite-based flame retardant or the halogen-containing flame retardant is added separately.

[0145] Comparison of the results of Examples 18, 19, and 11 shows that the addition of a flame retardant synergist and an antifungal agent can enhance the flame retardant and antibacterial efficiency of the flame retardant and antibacterial microspheres of the present invention, so that a higher flame retardancy level can be achieved with a smaller amount of additive.

[0146] Comparison of Examples 15-17 with Comparative Examples 4-6 shows that the flame-retardant antibacterial microspheres of the present invention also improve the flame retardancy and antibacterial properties of materials in other matrix resins such as PE, PA and PC / ABS.

[0147] A comparison between Comparative Example 2 and Comparative Example 10 reveals that the addition of an existing silver-based antibacterial agent reduces both the flame retardancy and tensile strength of the resin composition to which the flame retardant is added.

[0148] In summary, the single-component flame-retardant antibacterial microspheres of the present invention not only have high flame-retardant and antibacterial efficiency, but can also achieve a synergistic effect with the flame retardant in the prior art, and further have good dispersibility in the matrix, thereby overcoming the technical drawbacks of the prior art regarding the deterioration of the overall performance of the material caused by the insufficient dispersibility of the flame retardant and antibacterial agent in the matrix.

[0149] Although the present invention has been described and illustrated in detail by way of example, other modifications and variations within the spirit and scope of the present invention will be apparent to those skilled in the art. Furthermore, it should be understood that the various aspects, various portions of different embodiments, and various features recited in the present invention may be combined or substituted in whole or in part. Furthermore, those skilled in the art will understand that the above description is merely illustrative and is not intended to limit the present invention.

Claims

1. A flame-retardant antimicrobial agent which is a polymer microsphere having a guanidine salt grafted onto its surface, The polymer microspheres contain a crosslinked structure composed 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, and the monomer M is C ４ -C ９ selected from the group consisting of aliphatic olefins and mixtures thereof; the guanidine salt comprises at least one flame-retardant guanidine salt; The flame-retardant antibacterial agent, wherein the flame-retardant guanidine salt contains a phosphorus atom, a halogen atom, and / or a nitrogen atom other than the nitrogen atom of the guanidine group.

2. 2. The flame-retardant antibacterial agent according to claim 1, wherein the guanidine salt-grafted polymer microspheres have an average particle size in the range of 200 to 2000 nm.

3. The flame-retardant antibacterial agent according to claim 2, wherein the polymer microspheres are monodisperse polymer microspheres.

4. The flame-retardant antibacterial agent according to any one of claims 1 to 3, characterized in that the polymer microspheres as a graft substrate comprise a cross-linked alternating copolymer structure formed from maleic anhydride, a monomer M, and a cross-linking agent.

5. The guanidine salt-grafted polymer microspheres have a shell crosslinked structure, and / or The flame-retardant antibacterial agent according to any one of claims 1 to 3, characterized in that the cross-linking degree of the guanidine salt-grafted polymer microspheres is ≧50% as measured by solvent extraction method.

6. The flame-retardant antibacterial agent according to any one of claims 1 to 3, wherein the molar ratio of structural unit A to structural unit B is in the range of (0.5:1) to (1:0.5).

7. The monomer M is C ４ and / or C ５ The flame-retardant antibacterial agent according to any one of claims 1 to 3, which is an aliphatic monoolefin or diolefin, or a mixture of isomers thereof, or a mixture of monoolefins and diolefins.

8. The monomer M is C obtained from an ethylene cracking process ４ and / or C ５ The flame-retardant antibacterial agent according to claim 7, which is a fraction.

9. The flame-retardant antimicrobial agent according to any one of claims 1 to 3, wherein the crosslinking agent is selected from di- or polyfunctional vinyl-containing monomers capable of free radical polymerization.

10. The crosslinking agent is at least one selected from the group consisting of divinylbenzene and an acrylate crosslinking agent containing at least two acrylate groups, and the acrylate group is a crosslinking agent having the structural formula -O-C(O)-C(R')=CH ２ wherein R′ is H or C １ -C ４ The flame-retardant antimicrobial agent according to claim 9, which is an alkyl group.

11. The flame-retardant antibacterial agent according to claim 9, wherein the crosslinking agent is at least one selected from the group consisting of divinylbenzene, propylene glycol-based bis(meth)acrylate, ethylene glycol-based bis(meth)acrylate, trimethylolpropane tri(meth)acrylate, bis(trimethylolpropane) tetra(meth)acrylate, polyethylene glycol bis(meth)acrylate, phthalate ethylene glycol diacrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and ethoxylated multifunctional acrylates.

12. The flame-retardant antibacterial agent according to any one of claims 1 to 3, wherein the guanidine salt is at least one selected from the group consisting of small molecule guanidine salts and guanidine salt polymers.

13. 13. The flame retardant antimicrobial agent of claim 12, wherein the guanidine salt comprises at least one small molecule guanidine salt and at least one guanidine salt polymer.

14. 14. The flame retardant antimicrobial agent of claim 13, wherein both the small molecule guanidine salt and the guanidine salt polymer are flame retardant guanidine salts.

15. the small molecule guanidine salt is at least one selected from the group consisting of guanidine phosphate, guanidine hydrochloride, guanidine nitrate, guanidine hydrobromide, guanidine oxalate, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, and aminoguanidine salts; 13. The flame-retardant antibacterial agent according to claim 12, wherein the aminoguanidine salt is an inorganic or organic acid salt of monoaminoguanidine, diaminoguanidine, or triaminoguanidine, and is selected from the group consisting of carbonates, nitrates, phosphates, oxalates, hydrochlorides, hydrobromides, and sulfonates.

16. The flame-retardant antibacterial agent according to claim 12, characterized in that the guanidine salt polymer is at least one selected from the group consisting of polyhexamethylene(bi)guanidine hydrochloride, polyhexamethylene(bi)guanidine phosphate, polyhexamethylene(bi)guanidine acetate, polyhexamethylene(bi)guanidine oxalate, polyhexamethylene(bi)guanidine stearate, polyhexamethylene(bi)guanidine laurate, polyhexamethylene(bi)guanidine benzoate, polyhexamethylene(bi)guanidine sulfonate, and polyoxyethylene guanidine salt.

17. The flame-retardant antibacterial agent according to any one of claims 1 to 3, characterized in that the flame-retardant guanidine salt is at least one selected from the group consisting of guanidine phosphate, guanidine hydrochloride, guanidine hydrobromide, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, phosphate, hydrochloride, hydrobromide, nitrate, carbonate, oxalate, sulfonate, polyhexamethylene(bi)guanidine hydrochloride, and polyhexamethylene(bi)guanidine phosphate.

18. The flame-retardant antibacterial agent according to any one of claims 1 to 3, characterized in that the flame-retardant guanidine salt constitutes 30 to 100% by weight of the total weight of the guanidine salt.

19. A method for preparing the flame-retardant antibacterial agent according to any one of claims 1 to 18, comprising the steps of: preparing polymer microspheres by cross-linking copolymerization of maleic anhydride, a monomer M and a cross-linking agent in the presence of an initiator; and contacting said polymer microspheres with a guanidine salt to graft the guanidine salt onto the polymer microspheres, thereby obtaining said flame retardant antimicrobial agent.

20. The method according to claim 19, characterized in that the polymer microspheres as graft substrates are prepared by a self-stabilizing precipitation polymerization method.

21. The method of claim 21, wherein the monomer M comprises a first portion of the monomer M and a second portion of the monomer M, and when the monomer M is provided in one portion, the amount of the second portion of the monomer M is 0, and when the monomer M is provided in two portions, the amount of the second portion of the monomer M is greater than 0; the initiator comprises a first portion of the initiator and a second portion of the initiator, and when the initiator is provided in one portion, the amount of the second portion of the initiator is zero, and when the initiator is provided in two portions, the amount of the second portion of the initiator is greater than zero; and 20. The method of claim 19, characterized in that the method comprises the steps of: (1) contacting maleic anhydride with a first portion of the monomer M in an organic solvent in the presence of a first portion of the initiator to carry out a partial reaction, and then introducing a feed containing a crosslinker to carry out a subsequent reaction, wherein during the subsequent reaction, the reaction system comprises maleic anhydride, the monomer M, and the crosslinker; the crosslinker-containing feed comprises a crosslinker, optionally a second portion of the monomer M, and optionally a second portion of the initiator, and optionally a solvent, wherein the molar ratio of the second portion of the monomer M to the first portion of the monomer M is (0-100):100, and the molar ratio of the second portion of the initiator to the first portion of the initiator is (0-100):100; (2) A step of adding a guanidine salt to the product obtained in step (1) and continuing the reaction, thereby grafting the guanidine salt onto the surface of the product obtained in step (1).

22. 22. The method according to claim 21, characterized in that the organic solvent is selected from organic acid alkyl esters or mixtures of organic acid alkyl esters with alkanes or aromatic hydrocarbons.

23. In the step (1), the total amount of the first portion of the monomer M and the second portion of the monomer M in terms of terminal olefins is 50 to 150 moles per 100 moles of maleic anhydride; and / or the amount of the crosslinker is 1 to 40 moles per 100 moles of maleic anhydride; and / or 22. The method of claim 21, wherein the total amount of the first portion of initiator and the second portion of initiator is 0.05 to 10 moles relative to 100 moles of maleic anhydride.

24. The method according to any one of claims 19 to 23, characterized in that the initiator is at least one selected from the group consisting of dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, dodecanoyl peroxide, tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, azobisisobutyronitrile, and azobisisoheptanenitrile.

25. In the step (1), the reaction by contacting maleic anhydride with the first portion of the monomer M is carried out under an inert atmosphere at a temperature of 50 to 90°C and a pressure of 0.3 to 1 MPa; and / or 23. The method according to claim 21 or 22, characterized in that in step (1), the subsequent reaction by introducing a feed comprising a cross-linking agent is carried out at a temperature of 50 to 90°C and a pressure of 0.3 to 1 MPa.

26. In step (2), the reaction is carried out at a temperature of 0 to 100°C; and / or In step (2), the guanidine salt is used in an amount of 5 g to 5000 g per 1000 g of maleic anhydride; and / or 23. The method according to claim 21 or 22, characterized in that in step (2), the product obtained in step (1) is reacted, either directly in the form of a suspension or after drying, with a solution of a guanidine salt.

27. 27. Use of the flame retardant antimicrobial agent according to any one of claims 1 to 18 or prepared by the method according to any one of claims 19 to 26 as an additive in a flame retardant antimicrobial thermoplastic resin composition.

28. A flame-retardant antibacterial thermoplastic resin composition comprising a thermoplastic resin as a matrix and the flame-retardant antibacterial agent according to any one of claims 1 to 18 or the flame-retardant antibacterial agent prepared by the method according to any one of claims 19 to 26, wherein the flame-retardant antibacterial agent is used in an amount of 0.05 to 4.0 parts by weight per 100 parts by weight of the thermoplastic resin.

29. 30. The flame-retardant antimicrobial thermoplastic resin composition of claim 28, wherein the composition further comprises an aluminum hypophosphite-based flame retardant and / or a halogen-containing flame retardant.

30. 30. The flame retardant antimicrobial thermoplastic resin composition of claim 29, wherein the aluminum hypophosphite based flame retardant is selected from the group consisting of inorganic aluminum hypophosphites and aluminum alkylphosphinates, and combinations thereof.

31. The flame-retardant antibacterial thermoplastic resin composition according to claim 29, characterized in that the amount of the aluminum hypophosphite-based flame retardant is 0 to 2.0 parts by weight relative to 100 parts by weight of the thermoplastic resin.

32. 30. The flame retardant antimicrobial thermoplastic resin composition of claim 29, wherein the halogen-containing flame retardant is a melamine hydrohalide.

33. 30. The flame-retardant antibacterial thermoplastic resin composition of claim 29, wherein the amount of the halogen-containing flame retardant is 0 to 2.0 parts by weight relative to 100 parts by weight of the thermoplastic resin.

34. 34. The flame retardant antimicrobial thermoplastic resin composition of any one of claims 28 to 33, wherein the composition further comprises a flame retardant synergist and / or a mildewcide.

35. 35. The flame retardant antimicrobial thermoplastic resin composition of claim 34, wherein the flame retardant synergist is selected from the group consisting of 2,3-dimethyl-2,3-diphenylbutane, paracumene polymers, and combinations thereof.

36. 35. The flame-retardant antibacterial thermoplastic resin composition of claim 34, wherein the amount of the flame-retardant synergist is 0 to 1.0 parts by weight relative to 100 parts by weight of the thermoplastic resin.

37. The flame-retardant antibacterial thermoplastic resin composition according to claim 34, characterized in that the antifungal agent is at least one selected from the group consisting of pyrithione, isothiazolinone, 10,10'-oxybisphenoxarsine (OBPA), 3-iodo-2-propynyl-butyl-carbamate (IPBC), 2,4,4'-trichloro-2'-hydroxydiphenyl ether, and 2-(thiazol-4-yl)benzimidazole.

38. 35. The flame-retardant antibacterial thermoplastic resin composition of claim 34, wherein the mildew inhibitor is used in an amount of 0 to 5.0 parts by weight per 100 parts by weight of the thermoplastic resin.

39. 34. The flame-retardant antimicrobial thermoplastic resin composition of any one of claims 28 to 33, characterized in that the thermoplastic resin is selected from the group consisting 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 a polymer alloy or polymer mixture formed by one or more of the thermoplastic resins.

40. 34. The flame-retardant antimicrobial thermoplastic resin composition of any one of claims 28 to 33, characterized in that the composition further comprises at least one functional additive selected from the group consisting of antioxidants, light stabilizers, toughening agents, compatibilizers, pigments, and dispersants.

41. 41. Articles prepared from the flame retardant antimicrobial thermoplastic resin composition of any one of claims 28 to 40, in the form of fibers, films and fabrics.

42. 42. The article of claim 41, wherein the fabric is used for schools, hospitals, hotels, smart home appliances, or new energy vehicles.

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