CN115232352A

CN115232352A - Flame-retardant antibacterial polypropylene composition, polypropylene expanded bead, preparation method of polypropylene expanded bead and molded body

Info

Publication number: CN115232352A
Application number: CN202110442641.2A
Authority: CN
Inventors: 郭鹏; 吕明福; 徐耀辉; 张师军; 王宇韬; 毕福勇; 高达利; 邵静波; 白弈青
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Priority date: 2021-04-23
Filing date: 2021-04-23
Publication date: 2022-10-25

Abstract

The invention relates to a flame-retardant antibacterial polypropylene composition, a polypropylene expanded bead, a preparation method thereof and a polypropylene expanded bead forming body in the field of expanded polypropylene. The flame-retardant antibacterial polypropylene composition comprises the following components in parts by weight: 100 parts of polypropylene base resin; 0.05 to 4.0 portions of flame-retardant antibacterial agent; nucleation0.03-0.2 part of agent; the polypropylene base resin is random copolymer polypropylene; the flame-retardant antibacterial agent is a polymer microsphere with guanidine salt grafted on the surface, and the polymer microsphere comprises a crosslinking 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; monomer M is selected from C ₄ ‑C ₉ Aliphatic olefins and mixtures thereof; and the guanidine salt includes at least one guanidine salt having flame retardancy; the expanded bead has a good antibacterial effect, good flame retardance and a more compact and uniform cell structure.

Description

Flame-retardant antibacterial polypropylene composition, polypropylene expanded bead, preparation method of polypropylene expanded bead and molded body

Technical Field

The invention relates to the field of expanded polypropylene, and particularly relates to a flame-retardant antibacterial polypropylene composition, polypropylene expanded beads, a preparation method of the polypropylene expanded beads and a polypropylene expanded bead forming body.

Background

The EPP expanded beads are flammable. Polypropylene inflammable substance has large heat value during combustion and is accompanied with molten drops, so that flame is easy to spread. Furthermore, EPP beads have a cellular structure, which is itself less flame retardant. Most EPP beads at the present stage can not realize the flame retardant function, thereby limiting the application of the EPP beads in the field with higher requirements on flame retardance. At present, flame retardant PP compounded by halogen-containing organic matters and antimony trioxide is mainly adopted in domestic markets to produce the flame retardant PP. Plastic products containing halogen flame retardants can generate toxic and corrosive gases and a large amount of smoke during combustion, which causes great harm to the environment. In recent years, halogen flame-retardant materials are indicated to release high-toxicity carcinogenic substances such as benzofuran and dioxin in the processes of processing, burning and recovering in a plurality of environmental evaluation reports, and seriously harm the environment and human health. The european union of 2 months in 2003 was the first to issue a ROHS command (command for limiting hazardous substances in electronic and electrical products) for halogen restriction, and germany, the united states, japan, china, and the like have issued relevant environmental laws and regulations.

The existing mature polypropylene halogen-free flame retardant comprises hydroxide, phosphorus, nitrogen and the compound thereof. The hydroxide flame retardant is represented by magnesium hydroxide and aluminum hydroxide, and the addition amount is usually more than 60wt% to enable the polypropylene to reach the UL 94V 0 flame retardant grade required by the insulating sheet, but the processing of the flame retardant polypropylene is difficult. The phosphorus flame retardant is represented by red phosphorus and organic phosphate, and is lower in addition amount than hydroxide, but the insulation grade of the polypropylene board is reduced due to high water absorption rate and high leaching rate of the product. The nitrogen-based flame retardants are represented by melamines and triazines, but they do not allow products to achieve a high flame-retardant rating within a range of 0.125 to 0.75mm in thickness of a molded article or sheet. Therefore, the development of the low-smoke environment-friendly flame-retardant PP composite material has very important practical significance. In addition, the introduction of the polymer microspheres effectively reduces the addition of the flame retardant, and is beneficial to the improvement of the cellular structure of the polypropylene foaming beads and the improvement of the mechanical property of the foaming formed body. The existing environment-friendly flame retardant is low halogen, meets the IEC (International electrotechnical Commission) 61249-2-21 regulation, and is called as an environment-friendly flame retardant system.

In recent years, with the improvement of the living standard of people and the enhancement of the health consciousness, the demand of various antibacterial material products is continuously increased, wherein the antibacterial plastic products account for a large proportion, various living products, including refrigerators, air conditioners, various food containers, packaging bags, washing machines, toy products, dust collectors and the like, use various thermoplastic antibacterial plastics, and the antibacterial level of PP foamed products is also higher. The preparation of the antibacterial plastic is mainly realized by adding a certain amount of antibacterial agent in the plastic granulation process. The antibacterial agents are in various types, including inorganic antibacterial agents and organic antibacterial agents, wherein the inorganic antibacterial agents include Ag, zn-zeolite, ag, zn-zirconium phosphate, ag, zn-water-soluble glass and the like, and the organic antibacterial agents include quaternary ammonium salts, quaternary phosphonium salts, imidazoles, pyridines, organic metals and the like. Inorganic antibacterial agents and organic antibacterial agents have advantages and disadvantages, the inorganic antibacterial agents have high heat resistance, but the Ag antibacterial agents have the defects of easy color change, relatively large dosage and high cost; the organic antibacterial agent has the defects of high sterilization efficiency, small addition amount, poor heat resistance, easy precipitation, low safety and the like.

Disclosure of Invention

The invention provides a flame-retardant antibacterial polypropylene composition, and particularly relates to a flame-retardant antibacterial polypropylene composition, a polypropylene expanded bead, a preparation method of the polypropylene expanded bead and a polypropylene expanded bead molded body of the polypropylene expanded bead, in order to solve the problems that the foamed bead molded body in the prior art is poor in flame-retardant antibacterial performance, high in flame retardant addition amount, damaged in a cell structure and the like.

One of the purposes of the invention is to provide a flame-retardant antibacterial polypropylene composition, which comprises the following components in parts by weight:

100 parts of polypropylene base resin;

0.05 to 4.0 parts of flame-retardant antibacterial agent, preferably 0.1 to 2.8 parts, and more preferably 0.5 to 2 parts;

0.03 to 0.2 portion of nucleating agent; preferably 0.04 to 0.1 part;

the polypropylene base resin is random copolymer polypropylene;

in the particular implementation of the present application,

the random copolymerized polypropylene has the following characteristics: melt index MFR of 5 to 9g/10min, molecular weight distribution M _w /M _n =6 to 20; preferably, the random copolymerization polypropylene can be selected from at least one of ethylene propylene random copolymerization polypropylene, propylene Ding Mogui copolymerization polypropylene and ethylene propylene Ding Mogui copolymerization polypropylene.

The nucleating agent is a crystallization nucleating agent, and can be specifically selected from cyclic dicarboxylates or substituted aryl heterocyclic phosphates (alpha nucleating agents); preferably selected from disodium bicyclo [2,2,2] octane-2,3-dicarboxylate and/or 2,2' -methylenebis (4,6-di-tert-butylphenyl) sodium phosphate.

The flame-retardant antibacterial agent is a polymer microsphere with guanidine salt grafted on the surface, and the polymer microsphere comprises a crosslinking structure consisting of a structural unit A derived from maleic anhydride, a structural unit B derived from a monomer M and a structural unit C derived from a crosslinking agent; the monomer M is selected from C ₄ -C ₉ Aliphatic olefins and mixtures thereof; and, the guanidinium salt comprises at least one guanidinium salt having flame retardancy.

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

The average particle size of the guanidine salt grafted polymer microspheres is preferably 200-2000 nm. (e.g., 200nm, 250nm, 350nm, 450nm, 550nm, 650nm, 750nm, 850nm, 950nm, 1050nm, 1150nm, 1250nm, 1350nm, 1450nm, 1550nm, 1650nm, 1750nm, 1850nm, 2000nm, or any value therebetween). The average particle size is characterized by a number average particle size and is determined by means of a scanning electron microscope.

The polymeric microspheres are preferably monodisperse, i.e. uniform in particle size.

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

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

Here, the monomer M is selected from C ₄ -C ₉ Aliphatic olefins and mixtures thereof, preferably C4 and/or C5-aliphatic monoolefins or diolefins or isomer mixtures thereof or mixtures of monoolefins and diolefins, for example 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.

As said monomer M, it is possible to use carbon four and/or carbon five fractions from the oil refinery or ethylene industry, preferably from the petrochemical industry ethylene cracking. The carbon four fraction from ethylene cracking may include trans-2-butene, cis-2-butene, n-butane, n-butene, isobutene, and others. The carbon five fraction from ethylene cracking may include dienes (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 (butyne-2, 3-penten-1-yne), and others. The carbon four and carbon five fractions as ethylene cracking products are easily available, and the preparation of polymer microspheres by using such mixed monomers can help to improve the added value of the carbon four and carbon five fractions and enable the method of the present invention to be cost-reduced.

The crosslinking degree of the guanidine salt grafted polymer microsphere can be more than or equal to 50% (such as 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or any value between the above values), preferably more than or equal to 70%, and more preferably more than or equal to 90%. The degree of crosslinking of the flame retardant antimicrobial agent is indicative of the gel content, as measured by a solvent extraction method. The polymer microspheres have a dissolution content of not more than 8wt% (such as 1wt%, 2wt%, 3wt%, 4wt%, 5.5wt%, 6.5wt%, 7.5wt%, 8wt% or any value between the above values) in 5 times of the weight of acetone at 50 ℃ for 30 min; accordingly, the degree of crosslinking is preferably ≥ 92%.

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

Preferably, the first and second electrodes are formed of a metal,

the molar ratio of the structural unit a and the structural unit B may range from (0.5.

As the crosslinking agent, which may also be referred to as a crosslinking monomer, any suitable crosslinking monomer may be used, preferably a difunctional or more functional vinyl-containing monomer capable of undergoing free radical polymerization. Preferably, the crosslinking agent may be at least one of divinylbenzene and an acrylate-based crosslinking agent containing at least two acrylate-based groups; the acrylate group preferably has the formula: -O-C (O) -C (R') = CH ₂ R' is H or C1-C4 alkyl (such as methyl); more preferably, the acrylate group is an acrylate group and/or a methacrylate group.

More preferably, the crosslinking agent may be selected from one or more of divinylbenzene, propylene glycol-based di (meth) acrylate, ethylene glycol-based di (meth) acrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane tetraacrylate, trimethylolpropane tetramethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, phthalic acid ethylene glycol diacrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol penta (meth) acrylate, pentaerythritol hexa (meth) acrylate, ethoxylated polyfunctional acrylate, and the like; more preferably still, the first and second liquid crystal compositions are,

the propylene glycol di (meth) acrylate may be selected from one or more of 1,3-propylene glycol dimethacrylate, 1,2-propylene glycol dimethacrylate, 1,3-propylene glycol diacrylate, 1,2-propylene glycol diacrylate, and the like; the ethylene glycol type di (meth) acrylate may be selected from one or more of ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, tetraethylene glycol dimethacrylate, tetraethylene glycol diacrylate, etc.

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

The guanidine salt can be selected from one or more of small molecule guanidine salt and guanidine salt polymer. Preferably, the guanidinium salt comprises at least one small molecule guanidinium salt and at least one guanidinium salt polymer; more preferably, the small molecule guanidinium and the guanidinium polymer are both guanidinium salts having flame retardancy.

The small molecule guanidine salt can be 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 such as monoaminoguanidine, diaminoguanidine, and triaminoguanidine, as well as inorganic and organic acid salts such as carbonate, nitrate, phosphate, oxalate, hydrochloride, hydrobromide, and sulfonate. More preferably, the small molecule guanidine salt is selected from one or more of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, biguanidine hydrogen phosphate, nitrate, phosphate, hydrochloride, hydrobromide, sulfonate, and the like of monoaminoguanidine, diaminoguanidine, and triaminoguanidine; the small molecule guanidine salt is further preferably one or more of guanidine phosphate, guanidine hydrochloride, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, guanidine hydrobromide, triaminoguanidine nitrate, monoaminoguanidine nitrate, triaminoguanidine phosphate, triaminoguanidine hydrochloride, triaminoguanidine hydrobromide, triaminoguanidine sulfonate.

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

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

The polyhexamethylene (bis) guanidine hydrochloride mentioned above refers to polyhexamethylene guanidine hydrochloride and/or polyhexamethylene biguanide hydrochloride, and the like.

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

The flame retardant antimicrobial agent prepared and used in the present invention is described in application number 201911042238X, which is incorporated herein by reference in its entirety.

In some implementations of the present application,

the flame retardant antibacterial polypropylene composition preferably further comprises an aluminum hypophosphite type flame retardant and/or a halogen-containing flame retardant. The flame-retardant antibacterial microspheres and the aluminum hypophosphite flame retardant and/or the halogen-containing flame retardant have a synergistic effect, so that the total addition amount of the flame retardant can be obviously reduced under the condition of achieving the same flame-retardant effect.

The aluminum hypophosphite-based flame retardant may be selected from inorganic aluminum hypophosphite and aluminum alkyl phosphinates (e.g., at least one of aluminum diethylphosphinate, aluminum dipropylphosphinate, aluminum phenylphosphinate, etc.), and combinations thereof; preferably from inorganic aluminium hypophosphite and/or aluminium diethylphosphinate. The aluminum hypophosphite-based flame retardant may be used in an amount of 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, based on 100 parts by weight of the polypropylene base resin. The halogen-containing flame retardant is preferably melamine hydrohalide, more preferably Melamine Hydrobromide (MHB); the halogen-containing flame retardant may be used in an amount of 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, based on 100 parts by weight of the polypropylene base resin.

The flame retardant antibacterial thermoplastic resin composition preferably further comprises a flame retardant synergist and/or a mold inhibitor. The flame retardant synergist can further improve the flame retardant efficiency, and the mildew preventive can further improve the antibacterial efficiency, so that the total addition of the flame retardant or the antibacterial agent can be reduced under the condition of achieving the same flame retardant or antibacterial effect.

The flame retardant synergist can be at least one of 2,3-dimethyl-2,3-diphenylbutane (DMDPB, abbreviated as paraquat) and p-cumene polymer (poly paraquat). The flame retardant synergist may be used in an amount of 0 to 1.0 part by weight, preferably 0.05 to 1 part by weight, more preferably 0.05 to 0.6 part by weight, based on 100 parts by weight of the polypropylene base resin.

The mildew inhibitor can be at least one of pyridylthione, isothiazolinone, 10' -oxodiphenol Oxazine (OBPA), 3-iodine-2-propynyl butyl carbamate (IPBC), 2,4,4' -trichloro-2 ' -hydroxydiphenyl ether (triclosan), 2- (thiazole-4-yl) benzimidazole (thiabendazole) and the like with good mildew-proof effect. The pyrithione may be, for example, at least one selected from zinc pyrithione, copper pyrithione, dipyrithione and the like. The isothiazolinone may be, for example, at least one selected from 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-isothiazolone (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.

The mildewcide may 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, based on 100 parts by weight of the polypropylene base resin.

In some implementations of the present application,

the flame-retardant antibacterial polypropylene composition can contain a slipping agent;

the slipping agent may be used in an amount of 0.01 to 0.25 parts by weight, preferably 0.02 to 0.2 parts by weight, based on 100 parts by weight of the polypropylene base resin.

The slipping agent can be selected from stearate and/or organic carboxylic acid amide, wherein the stearate can be selected from calcium stearate and the like, and the organic carboxylic acid amide can be selected from at least one of erucamide, oleamide, stearic acid stearamide and N, N '-ethylene bisstearamide, and is preferably N, N' -ethylene bisstearamide.

In some embodiments, the flame retardant and antibacterial polypropylene composition may further comprise glycerol monostearate of the formula: c ₂₁ H ₄₂ O ₄ . The material can be dispersed into polypropylene during processing; preferably, the glycerol monostearate is added in an amount of 0.1-1 wt% of the flame-retardant antibacterial agent.

In specific use, other functional additives can be added, and the amount of the other functional additives can be 0.1-100 parts by weight based on 100 parts by weight of the thermoplastic resin, and the specific amount can be adjusted according to needs. The other functional auxiliary agents can comprise at least one of an antioxidant, a light stabilizer, a toughening agent, a compatilizer, a pigment, a dispersing agent and the like.

Another object of the present invention is to provide a method for preparing the flame retardant antibacterial polypropylene composition, which comprises the following steps:

(a) Mixing components including the polypropylene base resin, the flame-retardant antibacterial agent and the nucleating agent to obtain a blend; stirring and mixing equipment commonly used in the art can be used;

(b) Adding the blend into an extruder for extrusion and granulation;

preferably, in step (b), the extrusion temperature is from 180 to 230 ℃.

Preferably, the preparation method of the flame retardant antibacterial polypropylene composition comprises the following steps:

(1) The components of the flame-retardant antibacterial polypropylene composition according to one of the purposes of the invention are weighed according to the mixture ratio and are put into a high-speed stirrer to be mixed to obtain a blend. Preferably, the components including the polypropylene, the flame-retardant antibacterial agent, the flame retardant, the flame-retardant synergist, the nucleating agent and other auxiliary agents are put together and mixed in a high-speed mixer to obtain the blend.

(2) Extruding the mixture (for example, adding the mixture into a double-screw extruder, wherein the extrusion temperature can be 180-230 ℃), granulating and injection molding. The flame-retardant antibacterial polypropylene resin granules are prepared by the method.

The composition containing the polymer microspheres and the flame retardant is beneficial to improving the antibacterial flame retardant property of polypropylene, and can omit the use of the conventional foam cell nucleating agent such as talcum powder, silicon dioxide, calcium carbonate and the like for foaming beads.

Wherein the content of the first and second substances,

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

in the presence of an initiator, carrying out cross-linking copolymerization on components including maleic anhydride, the monomer M and the cross-linking agent to prepare polymer microspheres, and then contacting the polymer microspheres with guanidine salt to graft the guanidine salt onto the polymer microspheres to obtain the flame-retardant antibacterial agent;

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

In particular, the amount of the solvent to be used,

(1) In an organic solvent, in the presence of a first part of initiator, maleic anhydride is contacted with a first part of monomer M to react, then a feed containing a crosslinking agent (preferably a solution containing the crosslinking agent) is introduced, and the reaction is continued; the reaction system contains maleic anhydride, a monomer M and a cross-linking agent in the continuous reaction process; wherein the crosslinker-containing feed contains a crosslinker, optionally a second portion of monomer M and optionally a second portion of initiator and optionally a solvent;

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

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

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

In the step (1), the monomer M may be fed in one step (that is, the amount of the second part of the monomer M may be zero), or may be fed in two parts (that is, the monomer M is divided into the first part of the monomer M and the second part of the monomer M, and the amount of the second part of the monomer M is greater than 0). According to an embodiment of the present invention, the molar ratio between the second portion of monomers M and the first portion of monomers M may be (0 to 100) 100 (e.g. 0, 1.

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

Preferably, the organic solvent may be any solvent commonly used in solution polymerization, for example, the organic solvent includes organic acid alkyl ester, that is, the organic solvent may be selected from organic acid alkyl ester, or a mixture of organic acid alkyl ester and alkane, or a mixture of organic acid alkyl ester and aromatic hydrocarbon; wherein the organic acid alkyl esters include, but are not limited to: at least one of methyl formate, ethyl formate, methyl propyl ester, methyl butyl ester, methyl isobutyl ester, pentyl formate, methyl acetate, ethyl ester, propyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, pentyl acetate, isopentyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, isobutyl butyrate, isoamyl isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate, and ethyl phenylacetate; such alkanes include, but are not limited to: n-hexane and/or n-heptane. The aromatic hydrocarbons include, but are not limited to: at least one of benzene, toluene and xylene.

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

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

in the method for preparing the flame-retardant antibacterial agent, the amount of the initiator is not particularly required, and preferably, the total amount of the initiator (the total amount of the first part of the initiator and the second part of the initiator) can be 0.05 to 10mol, preferably 0.5 to 5mol, and more preferably 0.8 to 1.5mol, relative to 100mol of maleic anhydride.

In the step (1), the initiator may be fed in one step (i.e. the amount of the second part of the initiator may be zero), or may be fed in two parts (i.e. the first part of the initiator and the second part of the initiator are separated, and the amount of the second part of the initiator is more than 0). According to an embodiment of the present invention, the molar ratio between the second portion of initiator and the first portion of initiator may be (0 to 100) from 100 (e.g. 0, 1.

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

In the method for producing the flame-retardant antibacterial agent, the amount of the crosslinking agent is also not particularly limited as long as the desired degree of crosslinking can be achieved. Preferably, the crosslinking agent may be used in an amount of 1 to 40mol, preferably 6 to 20mol, with respect to 100mol of maleic anhydride.

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

The cross-linker feed may contain the cross-linker, optionally the remaining second part of monomer M and optionally the remaining second part of initiator and optionally a solvent, preferably in the form of a solution containing a solvent. The kind and content of the solvent in the solution containing the crosslinking agent are not particularly limited as long as the solute therein is sufficiently dissolved, and usually, the kind of the solvent in the solution containing the crosslinking agent may be the same as the organic solvent in the polymerization reaction (i.e., the organic acid alkyl ester is included as described above), and the content of the crosslinking agent in the solution containing the crosslinking agent may be 0.2 to 3mol/L.

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

in the step (1), the maleic anhydride is firstly contacted with the monomer M to perform partial reaction, that is, the maleic anhydride and the monomer M are not completely reacted, and only part of the maleic anhydride and the monomer M are subjected to polymerization reaction in the presence of the initiator, so that the unreacted maleic anhydride and the monomer M are subsequently reacted with the crosslinking agent. The conditions for contacting maleic anhydride with the monomer M to carry out the reaction may be conventional conditions as long as the maleic anhydride and the monomer M are controlled to carry out only partial polymerization reaction, and preferably, the conditions for contacting maleic anhydride with the first part of the monomer M to carry out the reaction include: the inert atmosphere (e.g., nitrogen) may be at a temperature of 50 to 90 deg.C (more preferably 60 to 70 deg.C), a pressure (gauge pressure or relative pressure) of 0.3 to 1MPa (more preferably 0.4 to 0.5 MPa), and a time of 0.5 to 4 hours (more preferably 0.5 to 2 hours).

In the step (1), after the maleic anhydride is contacted with the monomer M to perform partial reaction, a feed (preferably solution) containing a cross-linking agent is introduced to continue the reaction, so that the shell cross-linking structure is particularly favorably formed. The conditions for continuing the reaction may be conventional conditions as long as each substrate is allowed to participate in the reaction as much as possible, and preferably, the conditions for continuing the reaction may include: the temperature can be 50-90 ℃, the pressure can be 0.3-1 MPa, and the time can be 1-15 h. The temperature and pressure for continuing the reaction may be the same as or different from those for carrying out the reaction by contacting maleic anhydride with the monomer M as described above. According to a more preferred embodiment of the invention, the introduction of the solution containing the crosslinking agent continues the reaction in such a way that: and (2) dropwise adding the solution containing the cross-linking agent into the product obtained in the step (1) within 1-3 h at 50-90 ℃ (further preferably 60-70 ℃), and continuing to perform heat preservation reaction for 1-4 h.

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

adding the guanidine salt (preferably a guanidine salt solution, more preferably an aqueous solution) into the product (suspension) obtained in the step (1), and carrying out reaction by rapid stirring; the amount of the guanidine salt may be conventionally selected, and preferably, the amount of the guanidine salt may be 5g to 5000g, preferably 20g to 3000g, and more preferably 100g to 2000g, with respect to 1000g of maleic anhydride. The guanidine salt solution may be used in an amount of 500 to 10000g, preferably 1000 to 8000g, more preferably 1000 to 6000g, relative to 1000g of maleic anhydride. The concentration of the guanidinium salt solution may be 0.5 to 50 wt.%, preferably 1 to 30 wt.%, more preferably 1 to 20 wt.%.

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

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

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

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

And (3) further separating the final product obtained in the step (2) to obtain the guanidine salt flame-retardant antibacterial microsphere product grafted with guanidine salt, for example, separating the product according to the following method: centrifuging, washing with water, washing with an organic solvent (the washing solvent as described above, i.e., at least one of n-hexane, isohexane, cyclohexane, n-heptane, n-octane, isooctane, methanol, ethanol, propanol, isopropanol, diethyl ether, isopropyl ether, and methyl tert-butyl ether can be used), centrifuging, and drying (e.g., vacuum drying).

The inventor of the present invention found in research that, in the step (2), the suspension obtained in the step (1) and a guanidine salt solution (preferably an aqueous solution) can be directly subjected to a grafting reaction without performing an organic solvent removal step, and the guanidine salt flame-retardant antibacterial microsphere product of the present invention can also be effectively prepared. Therefore, according to a preferred embodiment of the present invention, in the step (2), the product (suspension) obtained in the step (1) can be directly reacted with a guanidine salt solution (one-pot method), so that a mixed system containing guanidine salt flame-retardant antibacterial microspheres is obtained, and the mixed system can be further separated to obtain guanidine salt flame-retardant antibacterial microspheres, for example, the separation is performed according to the following manner: standing for layering, using the organic phase for recycling, and performing centrifugal separation, water washing-centrifugal separation and drying (such as vacuum drying) on the heavy phase to obtain the guanidine salt flame-retardant antibacterial microspheres. The optimized method adopts a one-pot process, and the product post-treatment only needs one-time liquid-liquid separation, solid-liquid separation, washing and drying, so that the time consumption of a single batch can be effectively shortened, the process flow is simplified, unit equipment is reduced, and the energy consumption is effectively reduced; the process only needs one organic solvent as a reaction medium, the solvent can be recycled only through layering and drying operations, a special water distribution device is not needed, layering can be achieved in the reactor, the solvent can be recycled, distillation and purification are not needed, energy is saved, consumption is reduced, and pollution of the organic solvent to the environment can be effectively reduced.

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

The microspheres can be prepared by using carbon four and carbon five fractions from oil refining or ethylene industry, particularly carbon four and carbon five fractions from ethylene cracking products in petrochemical industry as monomers, so that a new scheme is provided for utilization of mixed olefin resources in petrochemical industry, and the additional value of the products is promoted.

The third purpose of the invention is to provide a flame-retardant antibacterial polypropylene foaming bead which is prepared according to the flame-retardant antibacterial polypropylene composition;

preferably, the density of the polypropylene expanded beads is less than 0.9g/cm ³ For example, it may be 0.01 to 0.49g/cm ³ . The polypropylene foaming bead has compact foam pores, uniform pore diameter, complete appearance without fracture and lower density.

The fourth purpose of the invention is to provide a preparation method of the flame-retardant antibacterial polypropylene expanded bead, which comprises the following steps:

granulating and cutting the flame-retardant antibacterial polypropylene composition to obtain polypropylene resin particles; foaming the obtained polypropylene resin particles to obtain the polypropylene resin particles;

preferably, the foaming method may be a reaction kettle dipping foaming method.

The granulation according to the method for preparing polypropylene expanded beads of the present invention can be carried out in various ways, for example, the polypropylene composition can be extruded into strands through one or more dies of a twin-screw or single-screw extruder and cut to obtain polypropylene particles, or an underwater microparticle pelletizing system can be used, and the specific operation process is well known to those skilled in the art.

According to a specific embodiment of the method for preparing polypropylene expanded beads of the present invention, the granulation process comprises:

(a) Adding the polypropylene composition and optional other auxiliary agents into a high-speed mixer according to a certain proportion, and uniformly mixing;

(b) Extruding the above mixture through a twin-screw extruder, hot-cutting, introducing into water at 75 deg.C or lower, preferably 70 deg.C or lower, more preferably 55-65 deg.C, and cutting to obtain granules with length/diameter ratio of 0.5-2.0, preferably 0.8-1.3, more preferably 0.9-1.1, and average weight of 0.1-20mg, preferably 0.2-10mg, more preferably 1-3mg. The length/diameter ratio as described herein is an average of 200 randomly selected polypropylene composition particles.

The steps of the granulation method can be adjusted according to actual conditions.

According to the method for preparing the polypropylene expanded beads, the foaming can be carried out in various conventional manners, for example, an extrusion foaming method can be adopted, a reaction kettle impregnation foaming method can be adopted, preferably, the reaction kettle impregnation foaming method is adopted, and the expanded beads obtained in the manner are in a non-crosslinked structure, so that the polypropylene modified material can be recycled, secondary pollution is avoided, and the requirement of recycling economy is met.

According to the method for preparing polypropylene expanded beads of the present invention, preferably, the expansion is performed by using a reaction kettle immersion foaming method, more preferably, the reaction kettle immersion foaming method comprises the following steps:

(1) In a high-pressure kettle, polypropylene resin particles are uniformly mixed with auxiliary agents such as a dispersion medium, a surfactant, a dispersing agent, a dispersion reinforcing agent and the like;

(2) Covering the autoclave tightly, discharging residual air in the autoclave by using an air discharging method, namely using a foaming agent, then continuously feeding the foaming agent into the autoclave, starting heating and primarily adjusting the pressure until the foaming agent is stable, then stirring the autoclave at a stirring speed of 50-150rmp, preferably 90-110rmp, and heating the autoclave at a constant speed to a temperature which is 0.1-5 ℃, preferably 0.5-1 ℃ lower than the expansion stability;

(3) Adjusting the pressure in the autoclave to a pressure required for foaming, the pressure (gauge pressure) being 1 to 10MPa, preferably 3 to 5MPa, raising the temperature to a foaming temperature at an average heating rate of 0.1 ℃/min, the foaming temperature being 0.1 to 5 ℃, preferably 0.5 to 1 ℃ lower than the melting temperature of the microparticles, and continuously stirring for 0.1 to 2 hours, preferably 0.25 to 0.5 hours, under the conditions of foaming temperature and pressure;

(4) The discharge port of the autoclave was opened to discharge the contents of the autoclave into a collection tank to obtain polypropylene expanded beads, and carbon dioxide gas was fed while discharging so that the pressure in the autoclave was maintained at about the foaming pressure before all the particles were completely foamed and entered the collection tank.

The foaming method steps can be adjusted according to actual conditions.

According to the method for preparing polypropylene expanded beads of the present invention, the dispersion medium may be any of various dispersion media capable of dispersing the polypropylene resin fine particles therein without dissolving the components thereof, and for example, may be at least one of water, ethylene glycol, glycerin, methanol, ethanol, and the like, and particularly preferably water. Preferably, the dispersion medium is used in an amount of 1000 to 5000 parts by weight, preferably 2500 to 3500 parts by weight, relative to 100 parts by weight of the polypropylene resin fine particles.

According to the method for preparing polypropylene expanded beads of the present invention, the surfactant may be any of various components that can promote the dispersion of the polypropylene resin particles in the dispersion medium, for example, at least one of stearic acid, sodium dodecylbenzenesulfonate, quaternary ammonium compound, lecithin, amino acid, betaine, fatty acid glyceride, sorbitan fatty acid, polysorbate, and the like, and particularly, sodium dodecylbenzenesulfonate is preferable. Preferably, the surfactant is used in an amount of 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, more preferably 0.1 to 0.5 parts by weight, relative to 100 parts by weight of the polypropylene resin fine particles.

According to the method for preparing the polypropylene expanded beads, the dispersant can be an organic dispersant or an inorganic dispersant, and preferably the inorganic dispersant. The inorganic dispersant may be at least one of natural or synthetic clay minerals (e.g., kaolin, mica, magnesium aluminum garnet, clay, etc.), alumina, titanium dioxide, basic magnesium carbonate, basic zinc carbonate, calcium carbonate, silica, zinc borate, iron oxide, etc., and particularly preferably kaolin. In order to effectively prevent the polypropylene resin particles from being melt-bonded to each other during foaming, the dispersant is preferably used in an amount of 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of the polypropylene resin particles.

According to the method for preparing polypropylene expanded beads of the present invention, the dispersion enhancer is added in order to improve the dispersion efficiency of the dispersant, i.e., to reduce the amount of the dispersant while retaining the function of preventing melt-bonding between particles. The dispersion enhancer may be any of various existing inorganic compounds having a solubility of 1mg in 100mL of water at 40 ℃ and providing a divalent or trivalent anion or cation. Examples of the dispersion-enhancing agent include, but are not limited to, at least one of magnesium nitride, magnesium nitrate, aluminum phosphate, magnesium sulfate, aluminum nitride, aluminum nitrate, aluminum sulfate, ferric chloride, ferric sulfate, ferric nitrate, and the like, preferably aluminum sulfate. In order to obtain polypropylene expanded beads having an apparent density of 100g/L or more, the dispersion-reinforcing agent is preferably used in an amount of 0.0001 to 1 part by weight, preferably 0.01 to 0.2 part by weight, based on 100 parts by weight of the polypropylene composition particles.

According to the method for preparing the polypropylene expanded beads, the foaming agent can be an organic physical foaming agent or an inorganic physical foaming agent. Among them, examples of the organic type physical blowing agent include, but are not limited to, at least one of aliphatic hydrocarbons such as propane, butane, pentane, hexane and heptane, alicyclic hydrocarbons such as cyclobutane and cyclohexane, and halogenated hydrocarbons such as chlorofluoromethane, trifluoromethane, 1,2-difluoroethane, 1,2,2,2-tetrafluoroethane, methyl chloride, ethyl chloride and methylene chloride, and the like. Examples of the inorganic type physical blowing agent include, but are not limited to, at least one of air, nitrogen, carbon dioxide, oxygen, and water. In order to ensure good stability (homogeneity), low cost and environmental friendliness of the apparent density of the resulting polypropylene expanded beads, the blowing agent is preferably carbon dioxide and/or nitrogen, particularly preferably carbon dioxide. In addition, the amount of the blowing agent to be used may be determined depending on the specific kind of the blowing agent, the foaming temperature, and the apparent density of the polypropylene expanded beads to be produced. For example, when nitrogen is used as the blowing agent and water is used as the dispersion medium, the pressure in the closed vessel (i.e., the pressure (gauge pressure) in the upper space in the closed vessel) at the time of depressurization in the foaming apparatus is controlled to 1 to 12MPa; when carbon dioxide is used as the blowing agent, the gauge pressure is controlled to 1 to 7MPa. Generally, the desired pressure in the upper space inside the closed vessel increases as the apparent density of the polypropylene composition pellets to be obtained decreases.

The fifth purpose of the invention is to provide the application of the flame-retardant antibacterial polypropylene composition or the flame-retardant antibacterial polypropylene expanded bead.

The sixth purpose of the invention is to provide a flame-retardant antibacterial polypropylene foaming bead forming body, wherein the flame-retardant antibacterial polypropylene foaming bead forming body is obtained by molding a product prepared according to the flame-retardant antibacterial polypropylene foaming bead and/or the method for preparing the flame-retardant antibacterial polypropylene foaming bead.

According to the present invention, the molding can be performed in various existing molding machines, and the molding conditions can be selected conventionally in the art, and it is known to those skilled in the art, and will not be described herein.

Through the technical scheme, the invention provides the polypropylene composition containing the flame retardant metal salt as the foam cell nucleating agent, and the polypropylene composition can be further prepared into flame-retardant antibacterial polypropylene foam beads, and the beads have a more compact and uniform cell structure, uniform pore diameter, complete appearance without fracture and lower density. In addition, the foaming bead is in a non-crosslinking structure, so that the foaming bead can be recycled, secondary pollution is avoided, and the requirement of circular economy is met. In addition, the molding prepared from the expanded bead has higher flame-retardant antibacterial performance and lower flame retardant addition amount, has good antibacterial effect and good flame retardance, and can be particularly suitable for manufacturing and used in schools, hospitals, hotels and other crowded places, intelligent household appliances, new energy automobiles and other emerging fields.

Drawings

FIG. 1 is a photographic cross-sectional view of expanded beads prepared in example 5;

FIG. 2 is a photograph showing a cross section of the expanded beads prepared in comparative example 5.

Detailed Description

While the present invention will be described in detail with reference to the following examples, it should be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the present invention.

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

The present invention will be described in detail below by way of examples.

In the following examples and comparative examples, the relevant data were obtained according to the following test methods:

(1) Melt index MI: the measurement was carried out according to the method specified in GB/T3682-2000, where the test temperature was 230 ℃ and the load was 2.16kg.

(2) Density of polypropylene and composition: measuring by a density gradient column method according to a method specified in GB/T1033.2-2010; the density of the expanded polypropylene beads was measured according to the standard of astm d 792.

(3) Surface resistivity of expanded bead molded body: GB/T1410-2006.

(4) Cell density was tested according to the following method:

firstly, observing the section of the polypropylene foaming bead by using a scanning electron microscope, selecting a certain area from an obtained electron microscope picture to obtain information such as the area of the area, the number of cells and the like, and obtaining the cell density of the bead by using the following formula:

wherein: n is the number of cells in the SEM photograph, M is a magnification, and A is the area (unit: cm) of the selected region in the SEM photograph ² )，

The expansion ratio of the polypropylene expanded beads is shown.

(5) And (3) antibacterial testing: the measurement was carried out according to the method specified in GB/T31402-2015.

(6) Compression strength test of molded article: A50X 25mm sample was cut out from the expanded bead molded body, and a compression strength test was conducted based on American ASTM standard D3575-08, and a compression test was conducted at a compression rate of 10mm/min, whereby a compression strength at which the molded body was compressed by 50% was obtained.

(7) Horizontal burning test of foam: UL94, flammability testing of equipment and appliance part materials.

Source of raw materials

The raw materials are all commercially available.

Glycerol monostearyl ester was purchased from Heda, ATMER129V.

Random copolymer polypropylene 4908: purchased from the petrochemical Yanshan division of China. The melt flow rate was 8. + -. 0.5g/10min (230 ℃ C., 2.16 kg).

Random copolymer polypropylene E680E: purchased from Shanghai Ministry of petrochemistry, china. The melt flow rate was 6.8. + -. 0.5g/10min (230 ℃ C., 2.16 kg).

Random copolymer polypropylene 5608: purchased from the petrochemical Yanshan division of China. The melt flow rate was 8. + -. 0.5g/10min (230 ℃ C., 2.16 kg).

Preparing a flame-retardant antibacterial agent:

XQ101:

(1) The composition of the mixed butylene gas is as follows: trans-2-butene, 40.83 wt%; cis-2-butene, 18.18 wt%; n-butane, 24.29 wt%; n-butenes, 9.52 wt%; isobutylene, 2.78 wt%; others, 4.4 wt%. Dissolving 100g of maleic anhydride and 2g of azobisisobutyronitrile into 800mL of isoamyl acetate in an autoclave to form a solution I, introducing metered mixed butene (the molar ratio of the maleic anhydride to an effective component (terminal olefin) in the mixed olefin is 1:1), and reacting for 1 hour at 70 ℃ and 0.5MPa in a nitrogen atmosphere;

(2) And dissolving 25g of divinylbenzene in 200mL of isoprene acetate to obtain a solution II, adding the solution II into the reaction system by a plunger pump, dropwise adding for 2 hours, and after dropwise adding, keeping the temperature of the reaction system for reaction for 3 hours.

(3) After the reaction, the pressure was released, and 200g of each of an aqueous solution of dihydroguanidine phosphate (15 wt%) and an aqueous solution of polyhexamethylene biguanide hydrochloride (15 wt%) was added and reacted at 80 ℃ for 3 hours. And standing and layering the reacted system, centrifuging and separating the heavy phase for 20 minutes under the condition of 5000rad/min by using a centrifuge, adding 4L of water into the obtained solid, stirring and washing the obtained solid, centrifuging and separating for 20 minutes under the condition of 5000rad/min by using the centrifuge, and drying the obtained solid in vacuum to obtain the flame-retardant antibacterial agent, namely the polymer microsphere with the guanidine salt grafted on the surface, which is No. 1. The average particle size of the obtained polymer microspheres is 1280nm. The weight percentage of the obtained polymer microspheres dissolved out in 5 times of acetone at 50 ℃ for 30min was 5.5%.

XQ102:

The flame-retardant antibacterial agent is prepared according to the method of example 1, except that the system reacted in the step (2) is centrifuged and separated for 30 minutes by a centrifuge under the condition of 5000rad/min to obtain the crosslinked mixed butylene/maleic anhydride polymer microspheres, and the crosslinked mixed butylene/maleic anhydride polymer microspheres are washed and purified by normal hexane and dried in vacuum. Then, the dried crosslinked mixed butene/maleic anhydride polymer microspheres were added to 400g of a mixed aqueous solution of guanidine dihydrogen phosphate (20 wt%), polyhexamethylene biguanide hydrochloride (20 wt%), and reacted at 80 ℃ for 3 hours. And centrifuging the reacted system for 20 minutes by a centrifuge under the condition of 5000rad/min, adding 4L of water into the obtained solid, stirring and washing the obtained solid, centrifuging the obtained solid for 20 minutes by the centrifuge under the condition of 5000rad/min, and drying the obtained solid in vacuum to obtain the flame-retardant antibacterial agent, namely the polymer microsphere 2# with the guanidinium grafted on the surface. The average particle size of the obtained polymer microspheres was 1310nm. The weight percentage of the obtained polymer microspheres dissolved out in 5 times of acetone at 50 ℃ for 30min was 5.6%.

XQ103:

(1) Dissolving 100g of maleic anhydride and 2g of azobisisobutyronitrile into 800mL of isoamyl acetate in an autoclave to form a solution I, introducing metered mixed butene (the composition is the same as that in example 1, the molar ratio of the maleic anhydride to an effective component (terminal olefin) in the mixed olefin is 1:1), and reacting for 2 hours at 70 ℃ and 0.4MPa in a nitrogen atmosphere;

(2) And dissolving 15g of divinylbenzene in 200mL of isoprene acetate to obtain a solution II, adding the solution II into the reaction system by a plunger pump, dropwise adding for 2 hours, and after dropwise adding, keeping the temperature of the reaction system for reaction for 3 hours.

(3) After the reaction, the autoclave was depressurized, and 200g of an aqueous solution of guanidine hydrobromide (20 wt%) and 200g of an aqueous solution of polyhexamethylene guanidine phosphate (20 wt%) were added thereto, respectively, and reacted at 60 ℃ for 7 hours. And standing and layering the reacted system, centrifuging and separating the heavy phase for 20 minutes under the condition of 5000rad/min by using a centrifuge, adding 4L of water into the obtained solid, stirring and washing the obtained solid, centrifuging and separating for 20 minutes under the condition of 5000rad/min by using the centrifuge, and drying the obtained solid in vacuum to obtain the flame-retardant antibacterial agent, namely the polymer microsphere with guanidine salt grafted on the surface # 3. The average particle size of the obtained polymer microspheres is 1210nm. The weight percentage of the obtained polymer microspheres dissolved out in 5 times of acetone at 50 ℃ for 30min was 6.5%.

XQ104:

(1) Dissolving 100g of maleic anhydride and 1.5g of azobisisobutyronitrile into 800mL of isoamyl acetate in an autoclave to form a first solution, introducing metered mixed butylene (the composition is the same as in example 1, the molar ratio of the maleic anhydride to the effective component (terminal olefin) in the mixed olefin is 1;

(2) 0.5g of azodiisobutyronitrile and 18g of divinylbenzene are dissolved in 200mL of isoamyl acetate to form a second solution, the second solution is added into the reaction system by a plunger pump, the dropwise addition is carried out for 2 hours, and after the dropwise addition is finished, the reaction system is kept for reaction for 3 hours.

(3) After the reaction, the autoclave was vented, and 200g of an aqueous solution of guanidine dihydrogen phosphate (20 wt%), 200g of an aqueous solution of guanidine hydrobromide (20 wt%) and 200g of an aqueous solution of polyhexamethylene guanidine phosphate (20 wt%) were added, respectively, to react at 60 ℃ for 10 hours. And standing and layering the reacted system, centrifuging and separating the heavy phase for 20 minutes under the condition of 5000rad/min by using a centrifuge, adding 4L of water into the obtained solid, stirring and washing the obtained solid, centrifuging and separating for 20 minutes under the condition of 5000rad/min by using the centrifuge, and drying the obtained solid in vacuum to obtain the flame-retardant antibacterial agent, namely the polymer microsphere 4# with guanidine salt grafted on the surface. The average particle size of the resulting polymeric microspheres was 1510nm. The weight percentage of the obtained polymer microspheres dissolved out in 5 times of acetone at 50 ℃ for 30min was 5.8%.

Examples 1 to 9 and comparative examples 1 to 4

Mixing a flame-retardant antibacterial agent, a flame retardant, a flame-retardant synergist, a mildew preventive, a nucleating agent, an antioxidant (hindered phenol antioxidant 1010: phosphite antioxidant 168=1 (weight ratio)), wherein the using amount of the antioxidant is 0.1 part by weight (relative to the using amount of the base resin being 100 parts by weight)), glycerol monostearate (tall grass, ATMER 129V; the using amount of the glycerol monostearate is five thousandths of the weight of the flame-retardant antibacterial agent) according to the proportion shown in the table 1, and stirring the mixture by using a dry powder machine to obtain uniformly mixed powder; adding the mixed powder and polypropylene into a high-speed mixer according to the proportion shown in the table 1 for mixing; and (3) putting the mixed material into a double-screw extruder, extruding, granulating and drying at 195-210 ℃ to obtain the flame-retardant antibacterial polypropylene resin granules. A part of the obtained pellets was put into an injection molding machine and injection-molded to obtain a heat-deformed sample strip, and the performance test was as shown in Table 2.

100 parts by weight of flame-retardant antibacterial polypropylene resin granules (containing polymer microspheres and flame retardant) are placed into a high-speed stirrer to be mixed for 30 seconds at high speed, then added into a LabLine100 microparticle preparation system, the torque is controlled to be about 65%, the rotating speed is 300rpm, and the granules are cut underwater to obtain polypropylene resin microparticles, wherein the average length/diameter ratio of the microparticles is 0.9.

Firstly, 100 parts by weight of polypropylene resin particles, 3000 parts by weight of dispersion medium (deionized water), 0.3 part by weight of surfactant (sodium dodecyl benzene sulfonate), 3 parts by weight of dispersant (kaolin) and 0.2 part by weight of dispersion reinforcing agent (aluminum sulfate) are added and mixed at one time in an autoclave; secondly, the vessel cover is first closed, using an inert blowing agent (CO) ₂ Or nitrogen, see table 2) discharging residual air in the reaction kettle through an exhaust valve and a pipeline, and removing the air in the reaction kettle; feeding an inert blowing agent into the autoclave, and initially adjusting the pressure until it stabilizes; the dispersion in the autoclave is subsequently stirred and heated to 0.5-1 ℃ below the expansion temperature with uniform heating. Then, adjusting the pressure in the kettle to reach the pressure required by foaming; raising the temperature to a foaming temperature at an average heating rate of 0.1 ℃/minute, the foaming temperature being 0.5-1 ℃ below the melting temperature of the microparticles; stirring is continued for 0.25 to 0.5 hour under the conditions of foaming temperature and pressure. Finally, opening a discharge port of the high-pressure autoclave, and discharging materials in the reaction kettle into a collecting tank to obtain polypropylene expanded beads; carbon dioxide gas was fed while the discharge was being carried out so that the pressure in the autoclave was maintained near the foaming pressure before all the particles were fully foamed and entered the collection tank. The resulting expanded bead density was measured using ASTM D792 and the specific data is shown in table 2.

TABLE 1 formulation of antibacterial flame retardant PP composition (in the table, the amounts are in parts by weight)

TABLE 2

As can be seen from Table 2, the expanded beads prepared in examples 1 to 9 have good mechanical properties and good antibacterial and flame retardant properties.

Compared with the comparative example 3, the polypropylene composition foamed molded body using the polyhexamethylene biguanide hydrochloride as the antibacterial agent has poorer antibacterial and flame retardant properties, and the polypropylene foamed bead molded body of the invention has better compression performance and antibacterial and flame retardant properties under the same addition amount. Example 5 in comparison with comparative example 4 shows a certain increase in compressive strength after addition of the nucleating agent.

As can be seen from the photographs of the cross sections of the expanded beads of comparative example 5 and comparative example 4 (see FIGS. 1 and 2), the expanded beads obtained after adding the nucleating agent have more uniform cells and better cell morphology.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. The flame-retardant antibacterial polypropylene composition comprises the following components in parts by weight:

100 parts of polypropylene base resin;

0.05 to 4.0 parts of flame-retardant antibacterial agent, preferably 0.1 to 2.8 parts;

0.03 to 0.2 portion of nucleating agent; preferably 0.04 to 0.1 part;

the polypropylene base resin is random copolymer polypropylene;

the flame-retardant antibacterial agent is a polymer microsphere with guanidine salt grafted on the surface, and the polymer microsphere comprises a crosslinking structure consisting of a structural unit A derived from maleic anhydride, a structural unit B derived from a monomer M and a structural unit C derived from a crosslinking agent;

wherein monomer M is selected from C ₄ -C ₉ Aliphatic olefins and mixtures thereof; and is

The guanidine salt at least comprises one guanidine salt with flame retardance;

preferably, the average particle size of the polymer microspheres with guanidine salt grafted on the surface is 200-2000 nm;

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

2. The flame retardant, antibacterial polypropylene composition according to claim 1, wherein:

the melt index MFR of the random copolymerization polypropylene is 5-9 g/10min;

preferably, the random copolymerization polypropylene is selected from at least one of ethylene propylene random copolymerization polypropylene, propylene Ding Mogui copolymerization polypropylene and ethylene propylene Ding Mogui copolymerization polypropylene.

3. The flame retardant, antibacterial polypropylene composition according to claim 1, wherein:

the nucleating agent is selected from the group consisting of cyclic dicarboxylates or substituted aryl heterocyclic phosphates, preferably from disodium bicyclo [2,2,2] octane-2,3-dicarboxylate and/or sodium 2,2' -methylenebis (4,6-di-tert-butylphenyl) phosphate.

4. The flame retardant, antibacterial polypropylene composition according to claim 1, wherein:

the dissolution of the polymer microspheres with guanidine salt grafted on the surface in acetone with the weight of 5 times of that of the polymer microspheres at 50 ℃ for 30min is less than or equal to 8wt%; and/or the presence of a gas in the gas,

the crosslinking degree of the polymer microsphere with the guanidine salt grafted on the surface is more than or equal to 50 percent, preferably more than or equal to 70 percent, and is measured by a solvent extraction method.

5. The flame retardant, antibacterial polypropylene composition according to claim 1, wherein:

the monomer M is a C4 and/or C5 aliphatic monoolefin or diolefin or an isomeric mixture thereof or a mixture of monoolefins and diolefins, preferably a carbon four and/or carbon five fraction, more preferably a carbon four and/or carbon five fraction obtained from an ethylene cracking process.

6. The flame retardant, antibacterial polypropylene composition according to claim 1, wherein:

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

7. The flame retardant, antibacterial polypropylene composition according to claim 1, wherein:

the cross-linking agent is selected from bifunctional or more than bifunctional vinyl-containing monomers capable of free radical polymerization; preferably, the crosslinking agent is selected from at least one of divinylbenzene and acrylate-based crosslinking agents containing at least two acrylate-based groups; the structural formula of the acrylate group is preferably: -O-C (O) -C (R') = CH ₂ R' is H or C1-C4 alkyl; more preferably, the acrylate group is an acrylate group and/or a methacrylate group;

more preferably, the crosslinking agent is selected from one or more of divinylbenzene, bis (meth) acrylate of propylene glycol, bis (meth) acrylate of ethylene glycol, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ditrimethylolpropane tetraacrylate, ditrimethylolpropane tetramethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, phthalic acid ethylene glycol diacrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and ethoxylated multifunctional acrylate; more preferably still, the first and second liquid crystal compositions are,

the propylene glycol di (meth) acrylate is selected from one or more of 1,3-propylene glycol dimethacrylate, 1,2-propylene glycol dimethacrylate, 1,3-propylene glycol diacrylate, 1,2-propylene glycol diacrylate; the ethylene glycol-based di (meth) acrylate is selected from one or more of ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, tetraethylene glycol dimethacrylate and tetraethylene glycol diacrylate.

8. The flame retardant, antibacterial polypropylene composition according to claim 1, wherein:

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

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

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

9. The flame retardant and antibacterial polypropylene composition according to claim 1, wherein:

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

10. The flame retardant, antibacterial polypropylene composition according to claim 1, wherein:

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

11. A flame retardant antimicrobial polypropylene composition according to any one of claims 1 to 10, characterized by comprising an aluminum hypophosphite based flame retardant and/or a halogen containing flame retardant;

wherein the aluminum hypophosphite-based flame retardant is preferably selected from at least one of inorganic aluminum hypophosphite and aluminum alkyl phosphinate (preferably at least one of aluminum diethyl phosphinate, aluminum dipropyl phosphinate, and aluminum phenyl phosphinate); more preferably at least one selected from inorganic aluminum hypophosphite and aluminum diethylphosphinate; preferably, the aluminum hypophosphite based flame retardant is used in an amount of 0 to 2.0 parts by weight, preferably 0.1 to 1.2 parts by weight, based on 100 parts by weight of the polypropylene base resin;

the halogen-containing flame retardant is preferably melamine hydrohalide, more preferably melamine hydrobromide, and is preferably used in an amount of 0 to 2.0 parts by weight, preferably 0.1 to 1.2 parts by weight, based on 100 parts by weight of the polypropylene base resin.

12. The flame retardant antimicrobial polypropylene composition according to any one of claims 1 to 10, comprising a flame retardant synergist;

based on 100 parts by weight of the polypropylene base resin,

the amount of the flame retardant synergist is 0 to 1.0 weight part, preferably 0.05 to 1 weight part;

preferably, the first and second electrodes are formed of a metal,

the flame retardant synergist is at least one of 2,3-dimethyl-2,3-diphenyl butane (DMDPB) and cumin polymer (poly-paraquat).

13. A flame retardant, antimicrobial polypropylene composition according to any one of claims 1 to 10, characterized by comprising a slip agent;

based on 100 parts by weight of the polypropylene base resin,

the amount of the slipping agent is 0.01 to 0.25 weight part, preferably 0.02 to 0.2 weight part;

the slipping agent is selected from stearate and/or organic carboxylic acid amide; wherein, the stearate is preferably selected from calcium stearate, and the organic carboxylic acid amide is preferably selected from at least one of erucamide, oleamide, stearic acid stearamide and N, N '-ethylene bisstearamide, and is preferably selected from N, N' -ethylene bisstearamide.

14. The flame retardant antibacterial polypropylene composition according to any one of claims 1 to 10, characterized by comprising a mold inhibitor;

the mildew preventive is selected from at least one of pyridylthione, isothiazolinone, 10' -oxodiphenol Oxazine (OBPA), 3-iodine-2-propynyl butyl carbamate (IPBC), 2,4,4' -trichloro-2 ' -hydroxydiphenyl ether (triclosan) and 2- (thiazole-4-yl) benzimidazole (thiabendazole);

preferably, the pyrithione is selected from at least one of zinc pyrithione, copper pyrithione, and dipyrithione; the isothiazolinone is at least one selected from 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).

Preferably, the mildewcide is used in an amount of 0 to 5.0 parts by weight, preferably 0.05 to 4.0 parts by weight, based on 100 parts by weight of the polypropylene base resin.

15. The method for preparing a flame retardant and antibacterial polypropylene composition according to any one of claims 1 to 14, comprising the steps of:

(a) Mixing components including the polypropylene base resin, the flame-retardant antibacterial agent and the nucleating agent to obtain a blend;

(b) Extruding and granulating the blend;

preferably, in step (b), the extrusion temperature is from 180 to 230 ℃.

16. The method for preparing a flame retardant and antibacterial polypropylene composition according to claim 15, wherein:

the preparation method of the flame-retardant antibacterial agent comprises the following steps:

crosslinking and copolymerizing components including maleic anhydride, the monomer M and the crosslinking agent in the presence of an initiator to obtain polymer microspheres, and then contacting the polymer microspheres with guanidine salt to graft the guanidine salt onto the polymer microspheres, so as to obtain the flame-retardant antibacterial agent; preferably, the polymeric microspheres used as the grafting base are prepared by a self-stabilizing precipitation polymerization process.

Preferably, the first and second electrodes are formed of a metal,

(1) In an organic solvent, in the presence of a first part of initiator, maleic anhydride is contacted with a first part of monomer M for reaction, and then a feed containing a cross-linking agent is introduced for continuous reaction; wherein the crosslinker-containing feed contains a crosslinker, optionally a second portion of monomer M and optionally a second portion of initiator and optionally a solvent;

(2) Adding guanidine salt into the product obtained in the step (1), and continuing the reaction to graft guanidine salt on the surface of the product obtained in the step (1).

17. The method for preparing a flame retardant antibacterial polypropylene composition according to claim 16, wherein:

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

the total amount of the first part of monomers M and the second part of monomers M in terms of terminal olefins is from 50 to 150mol, more preferably from 75 to 100mol, relative to 100mol of the maleic anhydride;

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

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

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

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

18. The method for preparing a flame retardant antibacterial polypropylene composition according to claim 16, wherein:

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

the total amount of the first part of the initiator and the second part of the initiator is 0.05 to 10mol, preferably 0.5 to 5mol, relative to 100mol of maleic anhydride; and/or the presence of a gas in the gas,

the molar ratio of the second part of the initiator to the first part of the initiator can be (0-100): 100;

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

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

19. The method for preparing a flame retardant antibacterial polypropylene composition according to claim 16, wherein:

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

the organic solvent is selected from organic acid alkyl ester, or a mixture of the organic acid alkyl ester and alkane, or a mixture of the organic acid alkyl ester and aromatic hydrocarbon; preferably, the organic acid alkyl ester is selected from at least one of methyl formate, ethyl formate, methyl propyl ester, methyl butyl ester, methyl isobutyl ester, amyl formate, methyl acetate, ethyl ester, 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 isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate and ethyl phenylacetate; the alkane is preferably selected from n-hexane and/or n-heptane; the aromatic hydrocarbon is preferably at least one selected from the group consisting of benzene, toluene and xylene; preferably, the organic solvent may be used in an amount of 50 to 150L with respect to 100mol of maleic anhydride.

20. The method for preparing a flame retardant antibacterial polypropylene composition according to claim 16, wherein:

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

the conditions for the reaction of the maleic anhydride in contact with the first portion of monomer M include: inert atmosphere, temperature is 50-90 ℃, pressure is 0.3-1 MPa, time is 0.5-4 h; and/or the presence of a gas in the gas,

the conditions for continuing the reaction include: the temperature is 50-90 ℃, the pressure is 0.3-1 MPa, and the time is 1-15 h.

21. The method for preparing a flame retardant antibacterial polypropylene composition according to claim 16, wherein:

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

the dosage of the guanidine salt is 5g to 5000g, preferably 20g to 3000g, relative to 1000g of maleic anhydride; preferably, the guanidinium salt is added as a solution, preferably an aqueous solution;

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

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

the conditions of the grafting reaction include: the temperature is 0 to 100 ℃, preferably 2.5 to 90 ℃.

22. A flame retardant antimicrobial polypropylene expanded bead prepared from the flame retardant antimicrobial polypropylene composition according to any one of claims 1 to 14 or prepared from the polypropylene composition prepared by the method according to any one of claims 15 to 21;

preferably, the density of the polypropylene expanded beads is less than 0.9g/cm ³ More preferably 0.01 to 0.49g/cm ³ 。

23. The method for preparing flame retardant antibacterial polypropylene expanded beads according to claim 22, comprising the steps of:

preferably, the foaming method is a reaction kettle dipping foaming method.

24. Use of a flame retardant and antibacterial polypropylene composition according to any one of claims 1 to 14 or a flame retardant and antibacterial polypropylene expanded bead according to claim 22.

25. A flame-retardant antibacterial polypropylene expanded bead molding body, which is obtained by molding the flame-retardant antibacterial polypropylene expanded bead according to claim 22 or the flame-retardant antibacterial polypropylene expanded bead prepared by the method according to claim 23.