CN112898766A - Hard antibacterial plastic material and preparation method thereof - Google Patents

Abstract

The invention discloses a hard antibacterial plastic material which comprises the following raw materials in parts by weight: 80-120 parts of polyether polyol, 1-3 parts of antibacterial agent, 0.5-1 part of flame retardant, 0.1-0.3 part of catalyst, 1-5 parts of cross-linking agent, 20-30 parts of foaming agent, 80-130 parts of isocyanate, 1-1.5 parts of foam stabilizer and 0.5-0.8 part of water; the invention also discloses a preparation method of the polyurethane foam material, which is characterized in that the polyurethane foam material is endowed with excellent antibacterial property and flame retardant property by adding the antibacterial agent and the flame retardant, and the polyurethane foam material is endowed with good dimensional stability and larger void ratio by adding the auxiliary agents such as the catalyst, the foaming agent, the cross-linking agent and the like, and the preparation method is simple, fast, environment-friendly and pollution-free, and especially has obvious application value on food heat insulation materials.

Description

Hard antibacterial plastic material and preparation method thereof

Technical Field

The invention belongs to the technical field of antibacterial plastic preparation, and particularly relates to a hard antibacterial plastic material and a preparation method thereof.

Background

Various products made of plastics are widely used in life and work of people due to their characteristics of light weight, excellent chemical stability, excellent electrical insulation and the like.

The rigid polyurethane foam plastic is mostly of a closed-cell structure, has the excellent characteristics of good heat insulation effect, light weight, large specific strength, convenient construction and the like, and also has the characteristics of sound insulation, shock resistance, electric insulation, heat resistance, cold resistance, solvent resistance and the like, is widely used for heat insulation materials of refrigerator bodies of refrigerators and freezers, cold storages, refrigerated trucks and the like, heat insulation materials of buildings, storage tanks and pipelines, is used for non-insulation occasions in a small amount, such as imitation wood, packaging materials and the like, generally speaking, the polyurethane rigid foam with lower density is mainly used as a heat insulation (heat preservation) material, and the polyurethane rigid foam with higher density can be used as a structural material (imitation wood).

However, the pure polyurethane foam material has no antibacterial property, is often corroded by mould and small animals thereof as a heat insulating material, and damages the integrity and the practicability thereof, and is flammable, the limited oxygen index of which is 17.3 percent, and the application range of the pure polyurethane foam material is not improved and is severely limited, so that the improvement of the rigid polyurethane foam material with good antibacterial property, flame retardance, heat resistance and strength is a technical problem which needs to be solved urgently at present.

Disclosure of Invention

The invention aims to provide a hard antibacterial plastic material and a preparation method thereof.

The technical problems to be solved by the invention are as follows:

in the prior art, a pure polyurethane foam material has no antibacterial property, is usually destroyed by mould and small animals as a heat insulating material, destroys the integrity and the practicability, is extremely flammable, has the limit oxygen index of 17.3 percent, is not improved, and seriously restricts the application range.

The purpose of the invention can be realized by the following technical scheme:

a hard antibacterial plastic material comprises the following raw materials in parts by weight: 80-120 parts of polyether polyol, 1-3 parts of antibacterial agent, 0.5-1 part of flame retardant, 0.1-0.3 part of catalyst, 1-5 parts of cross-linking agent, 20-30 parts of foaming agent, 80-130 parts of isocyanate, 1-1.5 parts of foam stabilizer and 0.5-0.8 part of water;

the hard antibacterial plastic material is prepared by the following steps:

firstly, adding polyether polyol, a cross-linking agent, an antibacterial agent, a flame retardant, a foaming agent, water and a foam stabilizer into a stirring tank, and stirring for 30-50min at the rotation speed of 300-;

secondly, adding isocyanate and a catalyst into a reaction kettle, and stirring for 30min under the condition that the rotating speed is 300-;

and thirdly, sequentially injecting the first component and the second component into a foaming machine, stirring for 30-60 seconds at the rotation speed of 300-500r/min, controlling the reaction temperature to be 25-30 ℃, injecting the mixture into a mold preheated to be 60-90 ℃, putting the formed rigid foam plastic and the mold into a drying oven at 90-120 ℃, drying for 4-6 hours, cooling to room temperature, and demolding to obtain the rigid antibacterial plastic material.

Further, the antibacterial agent is prepared by the following steps:

step S11, mixing microcrystalline cellulose and a sulfuric acid solution with the mass fraction of 64% according to the weight ratio of 1 g: adding 12-15mL of the solution into a three-neck flask, stirring for 2h at 55 ℃ and at the rotation speed of 300-;

step S12, mixing the cellulose nanocrystalline powder and deionized water according to the weight ratio of 1 g: adding 100mL of the activated cellulose nano-crystalline into a beaker, performing ultrasonic dispersion for 10-15min at the frequency of 30-50kHz, then adding 4-bromobutyryl chloride into the beaker, stirring for 50min at the rotation speed of 200-300r/min under the condition of water bath at the temperature of 50 ℃, washing precipitates for 3-5 times by using deionized water, and performing freeze drying to obtain activated cellulose nano-crystalline; adding activated cellulose nanocrystal, polyethyleneimine and dioxane into a beaker, magnetically stirring for 24 hours under the condition of 50-60 ℃ water bath, centrifuging, washing and drying to obtain grafted cellulose nanocrystal;

step S13, mixing the grafted cellulose nanocrystals with deionized water to prepare a grafted cellulose nanocrystal suspension A with the mass fraction of 1%, adding an oxidant into the suspension A, stirring at the rotating speed of 800r/min for 30min at room temperature, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the suspension to adjust the pH value to 10, slowly adding a sodium hypochlorite solution with the mass fraction of 15%, continuing to react for 20min, adding absolute ethyl alcohol to stop the reaction to obtain a mixture B, centrifuging the mixture B at the rotating speed of 10000r/min for 15min, washing the precipitate with an ethanol solution with the mass fraction of 35% until the washing solution is neutral, and freeze-drying to obtain modified cellulose nanocrystals;

and step S14, dispersing the modified cellulose nanocrystals in N, N-dimethylformamide, transferring the obtained dispersion liquid into a three-neck flask, adding polyethylene glycol and dibutyltin dilaurate under the protection of nitrogen, heating to 50 ℃, reacting for 30-60min under the condition of 500r/min, washing for 3 times by deionized water and absolute ethyl alcohol after the reaction is finished, and drying in an oven at 80-100 ℃ until the weight is constant to obtain the antibacterial agent.

Further, in step S12, the mass ratio of the cellulose nanocrystal powder to the 4-bromobutyryl chloride is 1: 0.2-0.5, the dosage ratio of the activated cellulose nanocrystal, the polyethyleneimine and the dioxane is 1 g: 1 g: 20-30 mL; in the step S13, the oxidizing agent is prepared from 2,2,6, 6-tetramethylpiperidine-1-oxyl, sodium bromide and deionized water in a dosage ratio of 29.7 mg: 318 mg: 10-15mL, wherein the volume ratio of the suspension A, the oxidant, the sodium hypochlorite solution and the absolute ethyl alcohol is 100: 10-13: 10: 5-8; in the step S14, the use amount ratio of the modified cellulose nanocrystal, N-dimethylformamide, polyethylene glycol and dibutyltin dilaurate is 5-10 g: 30-50 mL: 3-5 mL: 0.1-0.3 g.

The cellulose nanocrystal is prepared by taking microcrystalline cellulose as a raw material through a sulfuric acid hydrolysis method, compared with common cellulose, the cellulose nanocrystal has the characteristics of high strength, high purity, high crystallinity, high polymerization degree and the like, has wide source, no toxicity, no pollution, easy modification and biodegradability, because the surface of the cellulose nanocrystal has a plurality of hydroxyl groups, the cellulose nanocrystal is subjected to elimination reaction with 4-bromobutyryl chloride, 4-bromobutyryl chloride is used as a bridging link, polyethyleneimine replaces bromine atoms, polyethyleneimine antibacterial molecules are stably loaded on the surface of the cellulose nanocrystal to obtain grafted cellulose nanocrystal, unreacted hydroxyl on the surface of the grafted cellulose nanocrystal is oxidized into carboxyl through an oxidant compounded by 2,2,6, 6-tetramethylpiperidine-1-oxygen radical, sodium bromide and deionized water, and the carboxyl group is further subjected to esterification reaction with the hydroxyl group of polyethylene glycol, polyethylene glycol is grafted on the surface of the cellulose nanocrystal to obtain the antibacterial agent, and because the polyethyleneimine and the polyethylene glycol are grafted on the surface of the cellulose nanocrystal through chemical reaction, the antibacterial property and the dispersibility of the cellulose nanocrystal are endowed.

Further, the flame retardant is prepared by the following steps:

step S21, adding distilled water into a beaker, then dropwise adding 98% phosphoric acid solution into the beaker while stirring, controlling the dropwise adding speed to be 1-3 drops/second, cooling to room temperature after the dropwise adding is finished, sequentially adding natural crystalline flake graphite, potassium permanganate and zinc borate into the beaker, controlling the reaction temperature to be 50-55 ℃, stirring at the rotation speed of 200-300r/min for 40-60min, transferring the mixture into a dialysis bag after the reaction is finished, dialyzing in deionized water for 24h, changing water once during 6h, finally placing the mixture into an oven, and drying at 60 ℃ for 6-8h to obtain modified expandable graphite;

step S22, adding pentaerythritol and dimethyl sulfoxide into a four-neck flask, heating to 40 ℃, stirring at a rotating speed of 80r/min for 5-10min, adding toluene diisocyanate and 1, 4-dioxane into the four-neck flask, controlling the temperature to be constant, increasing the rotating speed to 200-300r/min, stirring for 15-25min, adding modified expandable graphite, an emulsifier OP-10 and dibutyltin dilaurate, heating to 80-85 ℃, reacting at a constant rotating speed for 6-10h, cooling to room temperature, filtering, washing a filter cake with deionized water until a washing solution is neutral, and drying in an oven at a temperature of 100-110 ℃ to constant weight to obtain the flame retardant.

Further, in the step S21, the mass ratio of the distilled water to the phosphoric acid solution to the natural flake graphite to the potassium permanganate to the zinc borate is 0.3-0.5: 4.5: 1: 0.25: 0.3; in step S22, the use ratio of pentaerythritol, dimethyl sulfoxide, toluene diisocyanate, 1, 4-dioxane, modified expandable graphite, emulsifier OP-10 and dibutyltin dilaurate is 2.72 g: 400 mL: 7.28 g: 200-240 mL: 100 g: 0.5 g: 0.24 g.

Potassium permanganate is used as an oxidant, phosphoric acid solution is used as an intercalating agent, zinc borate is used as an auxiliary intercalating agent to prepare modified expandable graphite, an original taste polymerization method is adopted, polyurethane is used as a shell structure, the modified expandable graphite is used as a core material to prepare a flame retardant, the interlayer spacing is increased due to mutual repulsion between graphite layers due to the existence of the intercalating agent, in the high-temperature expansion process, the converted gas of the intercalating agent escapes, the interlayer structure of the graphite is blown open, the volume is rapidly expanded in a high-power manner, fluffy and heat-insulating worm is produced to play a flame retardant role, the zinc borate releases crystal water when being heated to more than 300 ℃, the heat is absorbed, the temperature of a combustion surface is reduced, the zinc borate is decomposed by heat to form viscous liquid with good fluidity, and the viscous liquid comprises gaps and holes which cover the substrate when in combustion and generate B₂O₃The glassy film covers the polymer, inhibits the popcorn effect of the expanded graphite to a certain extent, improves the barrier effect of the residual carbon layer, slows down the continuous combustion of the material, and forms pyrophosphoric acid and metaphosphoric acid by heating and dehydrating phosphoric acid molecules under the high-temperature condition to form a compact coke layer, and blocks the entry of oxygen and heat to further play a flame retardant role.

Further, the polyether polyol is polyether polyol 4110.

Further, the catalyst is triethanolamine and dibutyltin dilaurate in a mass ratio of 1: 1 is prepared by compounding.

Further, the cross-linking agent is one or more of glycerol, pentaerythritol, trimethylolpropane, sorbitol and sucrose mixed in any proportion.

Further, the foaming agent is one or more of cyclopentane, isopentane and HFC-245fa which are mixed according to any proportion.

Further, the isocyanate is one or two of polymethylene polyphenyl polyisocyanate and toluene diisocyanate which are mixed in any proportion.

Further, the foam stabilizer is a silicone oil foam stabilizer AK-8805.

Further, the preparation method of the hard antibacterial plastic material specifically comprises the following steps:

firstly, adding polyether polyol, a cross-linking agent, an antibacterial agent, a flame retardant, a foaming agent, water and a foam stabilizer into a stirring tank, and stirring for 30-50min at the rotation speed of 300-;

secondly, adding isocyanate and a catalyst into a reaction kettle, and stirring for 30min under the condition that the rotating speed is 300-;

and thirdly, sequentially injecting the first component and the second component into a foaming machine, stirring for 30-60 seconds at the rotation speed of 300-500r/min, controlling the reaction temperature to be 25-30 ℃, injecting the mixture into a mold preheated to be 60-90 ℃, putting the formed rigid foam plastic and the mold into a drying oven at 90-120 ℃, drying for 4-6 hours, cooling to room temperature, and demolding to obtain the rigid antibacterial plastic material.

The invention has the beneficial effects that:

the invention takes polyether polyol and isocyanate as main materials, gives polyurethane foam material excellent antibacterial property and flame retardant property by adding antibacterial agent and flame retardant, and adds catalyst, foaming agent, cross-linking agent and other auxiliary agents, improves reaction efficiency, gives polyurethane foam material good dimensional stability and larger void ratio, and the preparation method is simple, rapid, environment-friendly and pollution-free, and has obvious application value especially on food heat insulation material, wherein, cellulose nanocrystalline is taken as carrier, polyethyleneimine is grafted by elimination and substitution reaction, polyethylene glycol is grafted by oxidation and esterification reaction, high molecular antibacterial agent is obtained, because of existence of polyethyleneimine and polyethylene glycol, cellulose nanocrystalline antibacterial property and good dispersion property are given, and because of existence of organic high molecular quaternary ammonium salt, polyethylene glycol and bridged 4-bromobutyryl chloride molecule, the heat resistance of the antibacterial agent is improved, polyethylene glycol molecular chains can be stretched into water like a polymer brush, the contact of rigid rodlike cellulose nanocrystals is effectively prevented, the agglomeration of a cellulose nanocrystal suspension system is avoided, the polyethylene glycol can be dissolved in most oil-soluble solvents, the compatibility of the cellulose nanocrystals in water phase and organic solvents is improved, the antibacterial agent is added into a polyurethane system, hydroxyl on the surface of the modified cellulose nanocrystals is wound with the polyurethane molecular chains to play a role of a physical cross-linking point, so that the interfaces of the modified cellulose nanocrystals and the polyurethane molecular chains are well combined, and the polyethylene glycol can form a rigid penetrating network with polyurethane as a filler, so that the antibacterial agent has a strong toughening effect, the modified cellulose nanocrystals and the polyurethane are cross-linked to form a three-dimensional network structure, the cross-linking degree of the polyurethane is improved, a compact film structure is formed, and the hardness of the polyurethane material is greatly improved, the compact network structure can effectively prevent the permeation and diffusion of water and improve the water resistance of the material; polyurethane is used as a shell structure, and modified expandable graphite is used as a core material to prepare the flame retardant, so that on one hand, the flame retardant can improve the flame-retardant and heat-insulating properties of the polyurethane material and promote the generation of a polyurethane pore structure, on the other hand, the treatment of the polyurethane shell structure can improve the compatibility of the flame retardant and a polyurethane matrix and reduce the damage of the flame retardant to a blast hole structure, thereby ensuring that the composite material has good heat-insulating property.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

A hard antibacterial plastic material comprises the following raw materials in parts by weight: 80 parts of polyether polyol, 1 part of antibacterial agent, 0.5 part of flame retardant, 0.1 part of catalyst, 1 part of crosslinking agent, 20 parts of foaming agent, 80 parts of isocyanate, 1 part of foam stabilizer and 0.5 part of water;

the hard antibacterial plastic material is prepared by the following steps:

firstly, adding polyether polyol, a cross-linking agent, an antibacterial agent, a flame retardant, a foaming agent, water and a foam stabilizer into a stirring tank, and stirring for 30min at the rotating speed of 300r/min to obtain a first component;

secondly, adding isocyanate and a catalyst into a reaction kettle, and stirring for 30min at the rotating speed of 300r/min to obtain a second component;

and thirdly, sequentially injecting the first component and the second component into a foaming machine, stirring for 30 seconds at the rotating speed of 300r/min, controlling the reaction temperature to be 25 ℃, injecting the mixture into a mold preheated to 60 ℃, putting the formed rigid foamed plastic and the mold into a 90 ℃ oven, drying for 4 hours, cooling to room temperature, and demolding to obtain the rigid antibacterial plastic material.

The antibacterial agent is prepared by the following steps:

step S11, mixing microcrystalline cellulose and a sulfuric acid solution with the mass fraction of 64% according to the weight ratio of 1 g: adding 12mL of the solution into a three-neck flask, stirring for 2 hours at the temperature of 55 ℃ and the rotating speed of 300r/min, then adding deionized water with the volume 5 times that of sulfuric acid solution, stirring for 20 minutes at a constant rotating speed, standing for 3 hours, pouring out supernatant, centrifuging the rest suspension in a centrifuge for 15 minutes at the rotating speed of 10000r/min, transferring the centrifuged suspension into a dialysis bag, dialyzing to be neutral, and finally freeze-drying for 5 hours at the temperature of-45 ℃ to obtain cellulose nanocrystal powder;

step S12, mixing the cellulose nanocrystalline powder and deionized water according to the weight ratio of 1 g: adding 100mL of the activated cellulose nano-crystalline into a beaker, performing ultrasonic dispersion for 10min at the frequency of 30kHz, then adding 4-bromobutyryl chloride into the beaker, stirring for 50min at the rotation speed of 200r/min under the condition of 50 ℃ water bath, washing precipitates for 3 times by using deionized water, and performing freeze drying to obtain activated cellulose nano-crystalline; adding activated cellulose nanocrystal, polyethyleneimine and dioxane into a beaker, magnetically stirring for 24 hours under the condition of 50 ℃ water bath, centrifuging, washing and drying to obtain grafted cellulose nanocrystal;

step S13, mixing the grafted cellulose nanocrystals with deionized water to prepare a grafted cellulose nanocrystal suspension A with the mass fraction of 1%, adding an oxidant into the suspension A, stirring at the rotating speed of 800r/min for 30min at room temperature, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the suspension to adjust the pH value to 10, slowly adding a sodium hypochlorite solution with the mass fraction of 15%, continuing to react for 20min, adding absolute ethyl alcohol to stop the reaction to obtain a mixture B, centrifuging the mixture B at the rotating speed of 10000r/min for 15min, washing the precipitate with an ethanol solution with the mass fraction of 35% until the washing solution is neutral, and freeze-drying to obtain modified cellulose nanocrystals;

and step S14, dispersing the modified cellulose nanocrystals in N, N-dimethylformamide, transferring the obtained dispersion liquid into a three-neck flask, adding polyethylene glycol and dibutyltin dilaurate under the protection of nitrogen, heating to 50 ℃, reacting for 30min under the condition of 500r/min, washing for 3 times by deionized water and absolute ethyl alcohol after the reaction is finished, and drying in an oven at 80 ℃ until the weight is constant to obtain the antibacterial agent.

In the step S12, the mass ratio of the cellulose nanocrystal powder to the 4-bromobutyryl chloride is 1: 0.2, the dosage ratio of the activated cellulose nanocrystal to the polyethyleneimine to the dioxane is 1 g: 1 g: 20 mL; in the step S13, the oxidizing agent is prepared from 2,2,6, 6-tetramethylpiperidine-1-oxyl, sodium bromide and deionized water in a dosage ratio of 29.7 mg: 318 mg: 10mL of the suspension A, an oxidant, a sodium hypochlorite solution and absolute ethyl alcohol in a volume ratio of 100: 10: 10: 5; in step S14, the ratio of the modified cellulose nanocrystal, N-dimethylformamide, polyethylene glycol, and dibutyltin dilaurate to each other is 5 g: 30mL of: 3mL of: 0.1 g.

The flame retardant is prepared by the following steps:

step S21, adding distilled water into a beaker, then dropwise adding a phosphoric acid solution with the mass fraction of 98% into the beaker, stirring while dropwise adding, controlling the dropwise adding speed to be 1 drop/second, cooling to room temperature after dropwise adding, sequentially adding natural crystalline flake graphite, potassium permanganate and zinc borate into the beaker, controlling the reaction temperature to be 50 ℃, stirring at the rotating speed of 200r/min for 40min, transferring the mixture into a dialysis bag after the reaction is finished, dialyzing in deionized water for 24h, changing water once during 6h, finally placing in an oven, and drying at 60 ℃ for 6h to obtain the modified expandable graphite;

step S22, adding pentaerythritol and dimethyl sulfoxide into a four-neck flask, heating to 40 ℃, stirring at a rotating speed of 80r/min for 5min, adding toluene diisocyanate and 1, 4-dioxane into the four-neck flask, controlling the temperature to be unchanged, increasing the rotating speed to 200r/min, stirring for 15min, adding modified expandable graphite, an emulsifier OP-10 and dibutyltin dilaurate, heating to 80 ℃, reacting for 6h at a constant rotating speed, cooling to room temperature, filtering, washing a filter cake with deionized water until a washing solution is neutral, and drying in a 100 ℃ oven to constant weight to obtain the flame retardant.

In the step S21, the mass ratio of the distilled water to the phosphoric acid solution to the natural crystalline flake graphite to the potassium permanganate to the zinc borate is 0.3: 4.5: 1: 0.25: 0.3; in step S22, the use ratio of pentaerythritol, dimethyl sulfoxide, toluene diisocyanate, 1, 4-dioxane, modified expandable graphite, emulsifier OP-10 and dibutyltin dilaurate is 2.72 g: 400 mL: 7.28 g: 200mL of: 100 g: 0.5 g: 0.24 g.

The polyether polyol is polyether polyol 4110, and the catalyst is triethanolamine and dibutyltin dilaurate in a mass ratio of 1: 1, the cross-linking agent is glycerol, the foaming agent is cyclopentane, the isocyanate is polymethylene polyphenyl polyisocyanate, and the foam stabilizer is silicone oil foam stabilizer AK-8805.

Example 2

A hard antibacterial plastic material comprises the following raw materials in parts by weight: 100 parts of polyether polyol, 2 parts of antibacterial agent, 0.8 part of flame retardant, 0.2 part of catalyst, 3 parts of crosslinking agent, 25 parts of foaming agent, 100 parts of isocyanate, 1.2 parts of foam stabilizer and 0.7 part of water;

the hard antibacterial plastic material is prepared by the following steps:

firstly, adding polyether polyol, a cross-linking agent, an antibacterial agent, a flame retardant, a foaming agent, water and a foam stabilizer into a stirring tank, and stirring for 40min at the rotating speed of 400r/min to obtain a first component;

secondly, adding isocyanate and a catalyst into a reaction kettle, and stirring for 30min at the rotating speed of 400r/min to obtain a second component;

and thirdly, sequentially injecting the first component and the second component into a foaming machine, stirring for 40 seconds at the rotating speed of 400r/min, controlling the reaction temperature to be 28 ℃, injecting the mixture into a mold preheated to 70 ℃, putting the formed rigid foamed plastic and the mold into a 110 ℃ oven, drying for 5 hours, cooling to room temperature, and demolding to obtain the rigid antibacterial plastic material.

The antibacterial agent is prepared by the following steps:

step S11, mixing microcrystalline cellulose and a sulfuric acid solution with the mass fraction of 64% according to the weight ratio of 1 g: adding 14mL of the solution into a three-neck flask, stirring for 2 hours at the temperature of 55 ℃ and the rotating speed of 400r/min, then adding deionized water with the volume 5 times that of sulfuric acid solution, stirring for 20 minutes at a constant rotating speed, standing for 4 hours, pouring out supernatant, centrifuging the rest suspension in a centrifuge at the rotating speed of 10000r/min for 18 minutes, then transferring the centrifuged suspension into a dialysis bag, dialyzing to be neutral, and finally freeze-drying at-45 ℃ for 8 hours to obtain cellulose nanocrystal powder;

step S12, mixing the cellulose nanocrystalline powder and deionized water according to the weight ratio of 1 g: adding 100mL of the activated cellulose nano-crystalline into a beaker, performing ultrasonic dispersion for 12min at the frequency of 40kHz, then adding 4-bromobutyryl chloride into the beaker, stirring for 50min at the rotation speed of 250r/min under the condition of 50 ℃ water bath, washing precipitates for 4 times by using deionized water, and performing freeze drying to obtain activated cellulose nano-crystalline; adding activated cellulose nanocrystal, polyethyleneimine and dioxane into a beaker, magnetically stirring for 24 hours under the condition of water bath at 55 ℃, centrifuging, washing and drying to obtain grafted cellulose nanocrystal;

step S13, mixing the grafted cellulose nanocrystals with deionized water to prepare a grafted cellulose nanocrystal suspension A with the mass fraction of 1%, adding an oxidant into the suspension A, stirring at the rotating speed of 800r/min for 30min at room temperature, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the suspension to adjust the pH value to 10, slowly adding a sodium hypochlorite solution with the mass fraction of 15%, continuing to react for 20min, adding absolute ethyl alcohol to stop the reaction to obtain a mixture B, centrifuging the mixture B at the rotating speed of 10000r/min for 15min, washing the precipitate with an ethanol solution with the mass fraction of 35% until the washing solution is neutral, and freeze-drying to obtain modified cellulose nanocrystals;

and step S14, dispersing the modified cellulose nanocrystals in N, N-dimethylformamide, transferring the obtained dispersion liquid into a three-neck flask, adding polyethylene glycol and dibutyltin dilaurate under the protection of nitrogen, heating to 50 ℃, reacting for 40min under the condition of 500r/min, washing for 3 times by deionized water and absolute ethyl alcohol after the reaction is finished, and drying in a 90 ℃ oven to constant weight to obtain the antibacterial agent.

In the step S12, the mass ratio of the cellulose nanocrystal powder to the 4-bromobutyryl chloride is 1: 0.4, the dosage ratio of the activated cellulose nanocrystal, the polyethyleneimine and the dioxane is 1 g: 1 g: 25 mL; in the step S13, the oxidizing agent is prepared from 2,2,6, 6-tetramethylpiperidine-1-oxyl, sodium bromide and deionized water in a dosage ratio of 29.7 mg: 318 mg: 12mL of the suspension A, an oxidant, a sodium hypochlorite solution and absolute ethyl alcohol in a volume ratio of 100: 12: 10: 7; in step S14, the ratio of the modified cellulose nanocrystal, N-dimethylformamide, polyethylene glycol, and dibutyltin dilaurate to each other is 8 g: 40mL of: 4mL of: 0.2 g.

The flame retardant is prepared by the following steps:

step S21, adding distilled water into a beaker, then dropwise adding a phosphoric acid solution with the mass fraction of 98% into the beaker, stirring while dropwise adding, controlling the dropwise adding speed to be 2 drops/second, cooling to room temperature after dropwise adding, sequentially adding natural crystalline flake graphite, potassium permanganate and zinc borate into the beaker, controlling the reaction temperature to be 52 ℃ and the rotating speed to be 250r/min, stirring for 50min, transferring the mixture into a dialysis bag after the reaction is finished, dialyzing for 24h in deionized water, changing water once during 6h, finally placing the mixture into an oven, and drying for 7h at 60 ℃ to obtain the modified expandable graphite;

step S22, adding pentaerythritol and dimethyl sulfoxide into a four-neck flask, heating to 40 ℃, stirring for 8min at a rotating speed of 80r/min, adding toluene diisocyanate and 1, 4-dioxane into the four-neck flask, controlling the temperature to be unchanged, increasing the rotating speed to 250r/min, stirring for 20min, adding modified expandable graphite, an emulsifier OP-10 and dibutyltin dilaurate, heating to 82 ℃, reacting for 8h at a constant rotating speed, cooling to room temperature, filtering, washing a filter cake with deionized water until a washing solution is neutral, and drying in an oven at 105 ℃ until the weight is constant to obtain the flame retardant.

In the step S21, the mass ratio of the distilled water to the phosphoric acid solution to the natural crystalline flake graphite to the potassium permanganate to the zinc borate is 0.4: 4.5: 1: 0.25: 0.3; in step S22, the use ratio of pentaerythritol, dimethyl sulfoxide, toluene diisocyanate, 1, 4-dioxane, modified expandable graphite, emulsifier OP-10 and dibutyltin dilaurate is 2.72 g: 400 mL: 7.28 g: 230 mL: 100 g: 0.5 g: 0.24 g.

The polyether polyol is polyether polyol 4110, and the catalyst is triethanolamine and dibutyltin dilaurate in a mass ratio of 1: 1, the cross-linking agent is glycerol, the foaming agent is cyclopentane, the isocyanate is polymethylene polyphenyl polyisocyanate, and the foam stabilizer is silicone oil foam stabilizer AK-8805.

Example 3

A hard antibacterial plastic material comprises the following raw materials in parts by weight: 120 parts of polyether polyol, 3 parts of antibacterial agent, 1 part of flame retardant, 0.3 part of catalyst, 5 parts of crosslinking agent, 30 parts of foaming agent, 130 parts of isocyanate, 1.5 parts of foam stabilizer and 0.8 part of water;

the hard antibacterial plastic material is prepared by the following steps:

firstly, adding polyether polyol, a cross-linking agent, an antibacterial agent, a flame retardant, a foaming agent, water and a foam stabilizer into a stirring tank, and stirring for 50min at the rotation speed of 500r/min to obtain a first component;

secondly, adding isocyanate and a catalyst into a reaction kettle, and stirring for 30min at the rotating speed of 500r/min to obtain a second component;

and thirdly, sequentially injecting the first component and the second component into a foaming machine, stirring for 60 seconds at the rotation speed of 500r/min, controlling the reaction temperature to be 30 ℃, injecting the mixture into a mold preheated to 90 ℃, putting the formed rigid foamed plastic and the mold into a 120 ℃ drying oven, drying for 6 hours, cooling to room temperature, and demolding to obtain the rigid antibacterial plastic material.

The antibacterial agent is prepared by the following steps:

step S11, mixing microcrystalline cellulose and a sulfuric acid solution with the mass fraction of 64% according to the weight ratio of 1 g: adding 15mL of the solution into a three-neck flask, stirring for 2 hours at the temperature of 55 ℃ and the rotating speed of 500r/min, then adding deionized water with the volume 5 times that of sulfuric acid solution, stirring for 20 minutes at a constant rotating speed, standing for 5 hours, pouring out supernatant, centrifuging the rest suspension in a centrifuge for 20 minutes at the rotating speed of 10000r/min, transferring the centrifuged suspension into a dialysis bag, dialyzing to be neutral, and finally freeze-drying at-45 ℃ for 10 hours to obtain cellulose nanocrystal powder;

step S12, mixing the cellulose nanocrystalline powder and deionized water according to the weight ratio of 1 g: adding 100mL of the activated cellulose nano-crystalline into a beaker, performing ultrasonic dispersion for 15min at the frequency of 50kHz, then adding 4-bromobutyryl chloride into the beaker, stirring for 50min at the rotation speed of 300r/min under the condition of 50 ℃ water bath, washing precipitates for 5 times by using deionized water, and performing freeze drying to obtain activated cellulose nano-crystalline; adding activated cellulose nanocrystal, polyethyleneimine and dioxane into a beaker, magnetically stirring for 24 hours under the condition of water bath at 60 ℃, centrifuging, washing and drying to obtain grafted cellulose nanocrystal;

step S13, mixing the grafted cellulose nanocrystals with deionized water to prepare a grafted cellulose nanocrystal suspension A with the mass fraction of 1%, adding an oxidant into the suspension A, stirring at the rotating speed of 800r/min for 30min at room temperature, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the suspension to adjust the pH value to 10, slowly adding a sodium hypochlorite solution with the mass fraction of 15%, continuing to react for 20min, adding absolute ethyl alcohol to stop the reaction to obtain a mixture B, centrifuging the mixture B at the rotating speed of 10000r/min for 15min, washing the precipitate with an ethanol solution with the mass fraction of 35% until the washing solution is neutral, and freeze-drying to obtain modified cellulose nanocrystals;

and step S14, dispersing the modified cellulose nanocrystals in N, N-dimethylformamide, transferring the obtained dispersion liquid into a three-neck flask, adding polyethylene glycol and dibutyltin dilaurate under the protection of nitrogen, heating to 50 ℃, reacting for 60min under the condition of 500r/min, washing for 3 times by deionized water and absolute ethyl alcohol after the reaction is finished, and drying in an oven at 100 ℃ until the weight is constant to obtain the antibacterial agent.

In the step S12, the mass ratio of the cellulose nanocrystal powder to the 4-bromobutyryl chloride is 1: 0.5, the dosage ratio of the activated cellulose nanocrystal to the polyethyleneimine to the dioxane is 1 g: 1 g: 30 mL; in the step S13, the oxidizing agent is prepared from 2,2,6, 6-tetramethylpiperidine-1-oxyl, sodium bromide and deionized water in a dosage ratio of 29.7 mg: 318 mg: 15mL of the suspension A, an oxidant, a sodium hypochlorite solution and absolute ethyl alcohol in a volume ratio of 100: 13: 10: 8; in step S14, the ratio of the modified cellulose nanocrystal, N-dimethylformamide, polyethylene glycol, and dibutyltin dilaurate to each other is 10 g: 50mL of: 5mL of: 0.3 g.

The flame retardant is prepared by the following steps:

step S21, adding distilled water into a beaker, then dropwise adding 98% phosphoric acid solution into the beaker while stirring, controlling the dropwise adding speed to be 3 drops/second, cooling to room temperature after the dropwise adding is finished, sequentially adding natural crystalline flake graphite, potassium permanganate and zinc borate into the beaker, controlling the reaction temperature to be 55 ℃, stirring at the rotating speed of 300r/min for 60min, transferring the mixture into a dialysis bag after the reaction is finished, dialyzing in deionized water for 24h, changing water once during 6h, finally placing in an oven, and drying at 60 ℃ for 8h to obtain the modified expandable graphite;

step S22, adding pentaerythritol and dimethyl sulfoxide into a four-neck flask, heating to 40 ℃, stirring at a rotating speed of 80r/min for 10min, adding toluene diisocyanate and 1, 4-dioxane into the four-neck flask, controlling the temperature to be unchanged, increasing the rotating speed to 300r/min, stirring for 25min, adding modified expandable graphite, an emulsifier OP-10 and dibutyltin dilaurate, heating to 85 ℃, reacting at a constant rotating speed for 10h, cooling to room temperature, filtering, washing a filter cake with deionized water until a washing solution is neutral, and drying in a drying oven at 110 ℃ until the weight is constant to obtain the flame retardant.

In the step S21, the mass ratio of the distilled water to the phosphoric acid solution to the natural crystalline flake graphite to the potassium permanganate to the zinc borate is 0.5: 4.5: 1: 0.25: 0.3; in step S22, the use ratio of pentaerythritol, dimethyl sulfoxide, toluene diisocyanate, 1, 4-dioxane, modified expandable graphite, emulsifier OP-10 and dibutyltin dilaurate is 2.72 g: 400 mL: 7.28 g: 240mL of: 100 g: 0.5 g: 0.24 g.

The polyether polyol is polyether polyol 4110, and the catalyst is triethanolamine and dibutyltin dilaurate in a mass ratio of 1: 1, the cross-linking agent is glycerol, the foaming agent is cyclopentane, the isocyanate is polymethylene polyphenyl polyisocyanate, and the foam stabilizer is silicone oil foam stabilizer AK-8805.

Comparative example 1

The antibacterial agent in example 1 was removed, and the remaining raw materials and preparation process were unchanged.

Comparative example 2

The flame retardant in example 2 was removed and the remaining raw materials and preparation were unchanged.

Comparative example 3

The comparative example is a rigid polyurethane foam material commonly available on the market.

The foams of examples 1-3 and comparative examples 1-3 were subjected to a performance test in accordance with GB/T8813-2008 for compressive strength, GB/T2406.2-2009 for Limiting Oxygen Index (LOI) for antibacterial performance, GB/T31402-2015 for Plastic surface antibacterial performance test method for antibacterial performance, and GB/T24128-2009 for mildew resistance in the Plastic mildew resistance test method for antibacterial performance.

As can be seen from the table above, the test equations of the compression strength, the limiting oxygen index and the antibacterial and mildewproof performance of the examples 1 to 3 are superior to those of the comparative examples 1 to 3, which shows that the polyurethane foam material prepared by the invention not only has excellent mechanical properties, but also has antibacterial, flame retardant and mildewproof performances, and has great application value in the fields of food heat preservation and insulation and the like.

The foregoing is merely exemplary and illustrative of the principles of the present invention and various modifications, additions and substitutions of the specific embodiments described herein may be made by those skilled in the art without departing from the principles of the present invention or exceeding the scope of the claims set forth herein.

Claims (10)

1. The hard antibacterial plastic material is characterized by comprising the following raw materials in parts by weight: 80-120 parts of polyether polyol, 1-3 parts of antibacterial agent, 0.5-1 part of flame retardant, 0.1-0.3 part of catalyst, 1-5 parts of cross-linking agent, 20-30 parts of foaming agent, 80-130 parts of isocyanate, 1-1.5 parts of foam stabilizer and 0.5-0.8 part of water;

the hard antibacterial plastic material is prepared by the following steps:

firstly, adding polyether polyol, a cross-linking agent, an antibacterial agent, a flame retardant, a foaming agent, water and a foam stabilizer into a stirring tank, and stirring for 30-50min at the rotation speed of 300-;

secondly, adding isocyanate and a catalyst into a reaction kettle, and stirring for 30min under the condition that the rotating speed is 300-;

and thirdly, sequentially injecting the first component and the second component into a foaming machine, stirring for 30-60 seconds at the rotation speed of 300-500r/min, controlling the reaction temperature to be 25-30 ℃, injecting the mixture into a mold preheated to be 60-90 ℃, putting the formed rigid foam plastic and the mold into a drying oven at 90-120 ℃, drying for 4-6 hours, cooling to room temperature, and demolding to obtain the rigid antibacterial plastic material.

2. A rigid antimicrobial plastic material according to claim 1, wherein said antimicrobial agent is prepared by the steps of:

step S11, mixing microcrystalline cellulose and a sulfuric acid solution with the mass fraction of 64% according to the weight ratio of 1 g: adding 12-15mL of the solution into a three-neck flask, stirring for 2h at 55 ℃ and at the rotation speed of 300-;

step S12, mixing the cellulose nanocrystalline powder and deionized water according to the weight ratio of 1 g: adding 100mL of the activated cellulose nano-crystalline into a beaker, performing ultrasonic dispersion for 10-15min at the frequency of 30-50kHz, then adding 4-bromobutyryl chloride into the beaker, stirring for 50min at the rotation speed of 200-300r/min under the condition of water bath at the temperature of 50 ℃, washing precipitates for 3-5 times by using deionized water, and performing freeze drying to obtain activated cellulose nano-crystalline; adding activated cellulose nanocrystal, polyethyleneimine and dioxane into a beaker, magnetically stirring for 24 hours under the condition of 50-60 ℃ water bath, centrifuging, washing and drying to obtain grafted cellulose nanocrystal;

step S13, mixing the grafted cellulose nanocrystals with deionized water to prepare a grafted cellulose nanocrystal suspension A with the mass fraction of 1%, adding an oxidant into the suspension A, stirring at the rotating speed of 800r/min for 30min at room temperature, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the suspension to adjust the pH value to 10, slowly adding a sodium hypochlorite solution with the mass fraction of 15%, continuing to react for 20min, adding absolute ethyl alcohol to stop the reaction to obtain a mixture B, centrifuging the mixture B at the rotating speed of 10000r/min for 15min, washing the precipitate with an ethanol solution with the mass fraction of 35% until the washing solution is neutral, and freeze-drying to obtain modified cellulose nanocrystals;

and step S14, dispersing the modified cellulose nanocrystals in N, N-dimethylformamide, transferring the obtained dispersion liquid into a three-neck flask, adding polyethylene glycol and dibutyltin dilaurate under the protection of nitrogen, heating to 50 ℃, reacting for 30-60min under the condition of 500r/min, washing for 3 times by deionized water and absolute ethyl alcohol after the reaction is finished, and drying in an oven at 80-100 ℃ until the weight is constant to obtain the antibacterial agent.

3. The hard antibacterial plastic material as claimed in claim 2, wherein the mass ratio of the cellulose nanocrystalline powder to the 4-bromobutyryl chloride in step S12 is 1: 0.2-0.5, the dosage ratio of the activated cellulose nanocrystal, the polyethyleneimine and the dioxane is 1 g: 1 g: 20-30 mL; in the step S13, the oxidizing agent is prepared from 2,2,6, 6-tetramethylpiperidine-1-oxyl, sodium bromide and deionized water in a dosage ratio of 29.7 mg: 318 mg: 10-15mL, wherein the volume ratio of the suspension A, the oxidant, the sodium hypochlorite solution and the absolute ethyl alcohol is 100: 10-13: 10: 5-8; in the step S14, the use amount ratio of the modified cellulose nanocrystal, N-dimethylformamide, polyethylene glycol and dibutyltin dilaurate is 5-10 g: 30-50 mL: 3-5 mL: 0.1-0.3 g.

4. The hard antibacterial plastic material as claimed in claim 1, wherein the flame retardant is prepared by the following steps:

step S21, adding distilled water into a beaker, then dropwise adding 98% phosphoric acid solution into the beaker while stirring, controlling the dropwise adding speed to be 1-3 drops/second, cooling to room temperature after the dropwise adding is finished, sequentially adding natural crystalline flake graphite, potassium permanganate and zinc borate into the beaker, controlling the reaction temperature to be 50-55 ℃, stirring at the rotation speed of 200-300r/min for 40-60min, transferring the mixture into a dialysis bag after the reaction is finished, dialyzing in deionized water for 24h, changing water once during 6h, finally placing the mixture into an oven, and drying at 60 ℃ for 6-8h to obtain modified expandable graphite;

step S22, adding pentaerythritol and dimethyl sulfoxide into a four-neck flask, heating to 40 ℃, stirring at a rotating speed of 80r/min for 5-10min, adding toluene diisocyanate and 1, 4-dioxane into the four-neck flask, controlling the temperature to be constant, increasing the rotating speed to 200-300r/min, stirring for 15-25min, adding modified expandable graphite, an emulsifier OP-10 and dibutyltin dilaurate, heating to 80-85 ℃, reacting at a constant rotating speed for 6-10h, cooling to room temperature, filtering, washing a filter cake with deionized water until a washing solution is neutral, and drying in an oven at a temperature of 100-110 ℃ to constant weight to obtain the flame retardant.

5. The hard antibacterial plastic material according to claim 4, wherein the mass ratio of the distilled water to the phosphoric acid solution to the natural crystalline flake graphite to the potassium permanganate to the zinc borate in step S21 is 0.3-0.5: 4.5: 1: 0.25: 0.3; in step S22, the use ratio of pentaerythritol, dimethyl sulfoxide, toluene diisocyanate, 1, 4-dioxane, modified expandable graphite, emulsifier OP-10 and dibutyltin dilaurate is 2.72 g: 400 mL: 7.28 g: 200-240 mL: 100 g: 0.5 g: 0.24 g.

6. The hard, antibacterial plastic material as claimed in claim 1, wherein the polyether polyol is polyether polyol 4110, and the catalyst is triethanolamine and dibutyltin dilaurate in a mass ratio of 1: 1, and the cross-linking agent is one or a mixture of more of glycerol, pentaerythritol, trimethylolpropane, sorbitol and sucrose in any proportion.

7. A rigid antimicrobial plastic material according to claim 1 wherein said blowing agent is one or more of cyclopentane, isopentane and HFC-245fa mixed in any proportion.

8. The hard, antibacterial plastic material as claimed in claim 1, wherein said isocyanate is one or two of polymethylene polyphenyl polyisocyanate and toluene diisocyanate mixed at any ratio.

9. A rigid, antimicrobial plastic material according to claim 1, wherein said foam stabilizer is silicone oil foam stabilizer AK-8805.

10. The method for preparing a rigid antimicrobial plastic material according to claim 1, characterized by comprising the following steps:

firstly, adding polyether polyol, a cross-linking agent, an antibacterial agent, a flame retardant, a foaming agent, water and a foam stabilizer into a stirring tank, and stirring for 30-50min at the rotation speed of 300-;

secondly, adding isocyanate and a catalyst into a reaction kettle, and stirring for 30min under the condition that the rotating speed is 300-;

and thirdly, sequentially injecting the first component and the second component into a foaming machine, stirring for 30-60 seconds at the rotation speed of 300-500r/min, controlling the reaction temperature to be 25-30 ℃, injecting the mixture into a mold preheated to be 60-90 ℃, putting the formed rigid foam plastic and the mold into a drying oven at 90-120 ℃, drying for 4-6 hours, cooling to room temperature, and demolding to obtain the rigid antibacterial plastic material.