Antibacterial and heat-resistant acrylic plate as well as preparation method and application thereof

Abstract

The preparation method comprises the following steps: preparing a polyurethane prepolymer solution from polyether glycol, diisocyanate and dimethylolpropionic acid as raw materials, adding hydroxypropyl methacrylate, carrying out a reaction to obtain a double-bond-terminated polyurethane solution, continuously adding a neutralizer, an initiator and an emulsifier, and carrying out a reaction to obtain the antibacterial and heat-resistant acrylic sheet material. The preparation method comprises the following steps: uniformly stirring and mixing, adding a silver nitrate aqueous solution, three-dimensional porous graphene and acrylic microspheres, stirring and emulsifying to obtain a premixed emulsion, introducing nitrogen into the premixed emulsion, stirring, polymerizing and reducing to obtain a composite emulsion; then fully mixing methyl methacrylate, the composite emulsion and azodiisobutyronitrile, heating and polymerizing to obtain pre-polymerized slurry; and finally, fully mixing the pre-polymerized slurry with azodiisobutyronitrile, pouring into a mold, heating and curing, naturally cooling to room temperature, and demolding, thereby obtaining the product. The obtained acrylic plate has excellent antibacterial property and heat resistance, and can be used for bathtub processing.

Description

Technical Field

[0001] The present invention relates to an acrylic sheet, in particular to an antibacterial and heat-resistant acrylic sheet and a preparation method and application thereof, belonging to the technical field of acrylic sheets. Background Art

[0002] Acrylic bathtubs have become quite popular in recent years. Made of polymethyl methacrylate (PMMA), acrylic bathtubs have various shapes, low prices, good surface finish, no rust, no fading, warm touch, and long service life. However, there are still many performances of acrylic bathtubs that need to be improved, especially the following two points:

[0003] 1. Antibacterial property: As the environment of bathtub is humid, it is a breeding ground for pathogenic microorganisms, which can be spread through the air in the form of droplets, through water in the form of fecal-oral contact, and through objects in the form of surface contact. Therefore, it is very necessary to improve the antibacterial property of acrylic bathtubs.

[0004] 2. Heat resistance: The glass transition temperature of pure polymethyl methacrylate is 105℃, which has poor heat resistance. The use temperature is usually below 80℃, and the thermal stability is poor. Bathtubs inevitably need to be in contact with hot water for a long time. Under the long-term influence of high temperature, acrylic bathtubs will have brittle fractures, softening, etc., which will affect the service life. Therefore, it is also very necessary to improve the heat resistance of acrylic bathtubs.

[0005] In order to improve the antibacterial and heat resistance of acrylic bathtubs, antibacterial and heat-resistant coatings can be prepared on the surface, but once the coating is damaged, the antibacterial and heat resistance will disappear. People have tried to add additives with antibacterial and heat-resistant properties to the original formula system, and improve the antibacterial and heat resistance through spraying, blending, melting and other processes, but the addition of additives often has compatibility issues, which affects the mechanical properties of the product and also affects the improvement of antibacterial and heat resistance.

[0006] Patent application CN104510385A discloses a production process for a heat-insulating independent acrylic bathtub, which uses an acrylic sheet as a substrate, wherein the acrylic sheet is a blister sheet, and includes a body and an outer cover, wherein a resin fiber reinforcement layer is provided on the outer surface of the body, and a resin fiber reinforcement layer is provided on the inner surface of the outer cover, and a foaming layer is filled in the gap between the body and the outer cover after being overlapped. This patent does not further improve the antibacterial and heat-resistant properties.

[0007] Patent application CN113801420A discloses a bathtub made of acrylic resin, melamine resin, pulp, talcum powder, quartz, zinc stearate, curing agent, antibacterial functional agent, antioxidant, titanium dioxide and other raw materials. The antibacterial functional agent of the patented technology is nano silver powder, which is easy to change color and is sensitive to the process. In addition, existing studies have shown that nano silver is easy to dissociate and agglomerate, and loses the corresponding antibacterial effect. In addition, the patent does not optimize and improve the heat resistance. Summary of the invention

[0008] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide an antibacterial and heat-resistant acrylic sheet and a preparation method and application thereof, which has excellent antibacterial and heat resistance and can be used for bathtub processing.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] 1. A method for preparing an antibacterial and heat-resistant acrylic sheet, the specific steps are as follows:

[0011] (1) firstly prepare a polyurethane prepolymer solution using polyether diol, diisocyanate and dimethylol propionic acid as raw materials, then add hydroxypropyl methacrylate to react to obtain a double-bond terminated polyurethane solution, continue to add a neutralizer, an initiator and an emulsifier, stir and mix, add a silver nitrate aqueous solution, three-dimensional porous graphene and acrylic microspheres, stir and emulsify to obtain a premixed emulsion, pass nitrogen into the premixed emulsion, stir and polymerize and reduce to obtain a composite emulsion;

[0012] (2) then fully mixing methyl methacrylate, the composite emulsion, and azobisisobutyronitrile, and heating and polymerizing to obtain a prepolymer slurry;

[0013] (3) Finally, the prepolymer slurry is fully mixed with azobisisobutyronitrile, poured into a mold, heated and cured, naturally cooled to room temperature (25° C.), and demolded to obtain the antibacterial and heat-resistant acrylic sheet.

[0014] Preferably, in step (1), the preparation method of the polyurethane prepolymer solution is as follows: polyether diol, diisocyanate, dimethylol propionic acid, dibutyl tin dilaurate and methyl methacrylate are added to a reaction kettle, and reacted at 70-80° C. for 5-6 hours to obtain the polyurethane prepolymer solution.

[0015] Further preferably, the mass ratio of polyether diol, diisocyanate, dimethylol propionic acid, dibutyl tin dilaurate and methyl methacrylate is 10:12-15:3-4:0.01-0.02:12-15, wherein the polyether diol is polyether 204, and the diisocyanate is 4,4'-dicyclohexylmethane diisocyanate, both of which are purchased from Green Union (Jining) Chemical Technology Co., Ltd.

[0016] Preferably, in step (1), hydroxypropyl methacrylate and polyether diol are of equal mass, and the process conditions for preparing the double-bond terminated polyurethane solution are: reacting at 70-80° C. for 3-4 hours.

[0017] Preferably, in step (1), the mass ratio of polyether diol, neutralizer, initiator, emulsifier, silver nitrate aqueous solution, three-dimensional porous graphene, and acrylic microspheres is 10:2-3:0.1-0.2:0.3-0.4:40-50:1-2:4-5.

[0018] Preferably, in step (1), the process conditions for stirring and emulsifying are: stirring and emulsifying at 2000-3000 r / min for 1-2 hours.

[0019] Preferably, in step (1), the process conditions for stirring polymerization and reduction are: stirring and heating to 50-55° C. at 2000-3000 r / min, keeping warm and continuing stirring for 4-5 hours, and naturally cooling to room temperature (25° C.) to obtain the composite emulsion.

[0020] Preferably, in step (1), the neutralizer is selected from triethylamine, sodium hydroxide or potassium hydroxide, the initiator is selected from ammonium persulfate or potassium persulfate, the emulsifier is selected from Span 80 or Span 60, and the concentration of the silver nitrate aqueous solution is 0.2-0.4 mol / L.

[0021] Preferably, in step (1), the three-dimensional porous graphene is prepared by the following method: first dissolving graphene oxide in water to obtain a graphene oxide aqueous solution with a concentration of 5 g / L, then adding polystyrene microspheres (purchased from Dongguan Mingyuan Plastic Co., Ltd., with a particle size of 100 nm) to the graphene oxide aqueous solution, treating with 400-500W ultrasonic oscillation for 3 hours, adjusting the pH to 8 with 1 mol / L sodium hydroxide solution, filtering out the solid, drying, and calcining at 800°C for 2-3 hours to achieve decomposition of the polystyrene microspheres and reduction of the graphene oxide, thereby obtaining the three-dimensional porous graphene; wherein the amount of polystyrene microspheres used is 3 times the mass of the graphene oxide.

[0022] Preferably, in step (1), the acrylic microspheres are prepared by the following method, based on parts by mass: 15 to 18 parts of ethoxylated bisphenol A dimethacrylate (purchased from Wuhan Tosoh Chemical Technology Co., Ltd.), 40 to 45 parts of methyl methacrylate, 40 to 45 parts of Japanese refined wax (EP-1400, Tianjin Hengsheng Xinyuan International Trade Co., Ltd.), 2 to 3 parts of bis(4-dodecylbenzene) iodonium hexafluoroantimonate (purchased from Wuhan Shuer Biotechnology Co., Ltd.), and 3 to 5 parts of wetting agent (BYK-DYNWET 800N, purchased from Guangzhou Si Tuyuan Chemical Co., Ltd.), mixed evenly at 50 to 60° C., filtered, sprayed and atomized, and simultaneously cured by electron beam radiation, and after being cured into spheres, dropped into 1,1,2,2-tetrabromoethane, collected and dried to obtain the obtained product.

[0023] Further preferably, the process conditions for electron beam radiation curing are: nitrogen concentration 200-300 mg / L, temperature 15-20° C., electron beam dose 50-60 kGy.

[0024] Preferably, in step (2), the mass ratio of methyl methacrylate, composite emulsion and azobisisobutyronitrile is 100:3-4:0.03-0.04.

[0025] Preferably, in step (2), the process conditions for heating polymerization are: polymerization reaction at 65-75° C. for 40-50 minutes.

[0026] Preferably, in step (3), the amount of azobisisobutyronitrile used is 0.02 to 0.03% of the mass of methyl methacrylate in step (2).

[0027] Preferably, in step (3), the process conditions for heating and curing are: standing at 70-75° C. for 2-3 hours, and standing at 110-120° C. for 2-3 hours.

[0028] 2. An antibacterial and heat-resistant acrylic sheet is obtained by the above-mentioned preparation method.

[0029] 3. Application of the aforementioned antibacterial and heat-resistant acrylic sheet in bathtub processing.

[0030] Preferably, the acrylic sheet is firstly vacuum-formed to obtain a bathtub body, and then the bathtub body is cut, perforated and polished to obtain a bathtub.

[0031] More preferably, the process conditions of the vacuum forming are: heating temperature 190-200° C., vacuum forming, and holding time 5-7 minutes.

[0032] Beneficial effects of the present invention:

[0033] The present invention first uses polyether diol, diisocyanate and dimethylol propionic acid as raw materials to prepare a polyurethane prepolymer solution, then adds hydroxypropyl methacrylate, reacts to obtain a double-bond terminated polyurethane solution, continues to add a neutralizer, an initiator and an emulsifier, stirs and mixes, adds a silver nitrate aqueous solution, a three-dimensional porous graphene, and acrylic microspheres, stirs and emulsifies to obtain a premixed emulsion, passes nitrogen into the premixed emulsion, stirs and polymerizes and reduces to obtain a composite emulsion; then methyl methacrylate, the composite emulsion, and azobisisobutyronitrile are fully mixed, heated and polymerized to obtain a prepolymer slurry; finally, the prepolymer slurry is fully mixed with azobisisobutyronitrile, poured into a mold, heated and cured, naturally cooled to room temperature, and demolded to obtain an antibacterial and heat-resistant acrylic sheet. The acrylic sheet obtained by the present invention has excellent antibacterial and heat resistance and can be used for bathtub processing.

[0034] The technical key of the present invention is that a composite emulsion is added when preparing the prepolymer slurry, and the polyurethane containing carboxyl in the composite emulsion can chelate the nano silver generated by reducing silver nitrate to avoid agglomeration, thereby achieving better antibacterial and heat-resistant effects. The composite emulsion also contains three-dimensional porous graphene and acrylic microspheres, and the nano silver generated by reducing silver nitrate is deposited on the surface of the three-dimensional porous graphene and acrylic microspheres, and the high molecular polymer encapsulates them, thereby improving the compatibility in the entire system, avoiding agglomeration, and improving the antibacterial and heat-resistant properties of the product.

[0035] Three-dimensional porous graphene has certain antibacterial and heat-resistant properties, and can work synergistically with nano-silver. The particle size of acrylic microspheres is about 200nm, with a large specific surface area, which can work synergistically with three-dimensional porous graphene and nano-silver to further improve the antibacterial and heat-resistant properties of the product. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with embodiments. It should be noted that the following description is only for explaining the present invention and does not limit its contents.

[0037] Embodiment 1:

[0038] A method for preparing an antibacterial and heat-resistant acrylic sheet, the specific steps are as follows:

[0039] (1) 1 kg of polyether diol, 1.2 kg of diisocyanate, 0.3 kg of dihydroxymethyl propionic acid, 0.001 kg of dibutyltin dilaurate and 1.2 kg of methyl methacrylate were added to a reaction kettle, and reacted at 70° C. for 5 hours to obtain a polyurethane prepolymer solution; then 1 kg of hydroxypropyl methacrylate was added to the polyurethane prepolymer solution, and reacted at 70° C. for 3 hours to obtain a double-bond terminated polyurethane solution, and 0.2 kg of a neutralizer, 0.01 kg of an initiator and 0.03 kg of an emulsifier were added, and stirred to mix, and 4 kg of a silver nitrate aqueous solution, 0.1 kg of a three-dimensional porous graphene and 0.4 kg of acrylic microspheres were added, and stirred and emulsified to obtain a premixed emulsion, and nitrogen was passed through the premixed emulsion, and stirred, polymerized and reduced to obtain a composite emulsion;

[0040] (2) then 100 kg of methyl methacrylate, 3 kg of the composite emulsion, and 0.03 kg of azobisisobutyronitrile were fully mixed and heated for polymerization to obtain a prepolymer slurry;

[0041] (3) Finally, the prepolymer slurry is fully mixed with 0.02 kg of azobisisobutyronitrile, poured into a mold, heated and cured, naturally cooled to room temperature (25° C.), and demolded to obtain the antibacterial and heat-resistant acrylic sheet.

[0042] Wherein, in step (1), the polyether diol is polyether 204, and the diisocyanate is 4,4'-dicyclohexylmethane diisocyanate, both of which are purchased from Green Union (Jining) Chemical Technology Co., Ltd.

[0043] In step (1), the process conditions for stirring and emulsifying are: stirring and emulsifying at 2000 r / min for 1 hour.

[0044] In step (1), the process conditions for stirring polymerization and reduction are: stirring and heating to 50° C. at 2000 r / min, keeping the temperature and stirring for 4 hours, and naturally cooling to room temperature (25° C.) to obtain the composite emulsion.

[0045] In step (1), the neutralizing agent is triethylamine, the initiator is ammonium persulfate, the emulsifier is Span 80, and the concentration of the silver nitrate aqueous solution is 0.2 mol / L.

[0046] In step (1), the three-dimensional porous graphene is prepared by the following method: firstly dissolving graphene oxide in water to obtain a graphene oxide aqueous solution with a concentration of 5 g / L, then adding polystyrene microspheres (purchased from Dongguan Mingyuan Plastic Co., Ltd., with a particle size of 100 nm) to the graphene oxide aqueous solution, treating with 400W ultrasonic oscillation for 3 hours, adjusting the pH to 8 with 1 mol / L sodium hydroxide solution, filtering out the solid, drying, and calcining at 800°C for 2 hours to achieve decomposition of the polystyrene microspheres and reduction of the graphene oxide, thereby obtaining the three-dimensional porous graphene; wherein the amount of the polystyrene microspheres is 3 times the mass of the graphene oxide.

[0047] In step (1), the acrylic microspheres are prepared by the following method: 15 kg of ethoxylated bisphenol A dimethacrylate (purchased from Wuhan Tosoh Chemical Technology Co., Ltd.), 40 kg of methyl methacrylate, 40 kg of Japanese refined wax (EP-1400, Tianjin Hengsheng Xinyuan International Trade Co., Ltd.), 2 kg of bis(4-dodecylbenzene) iodonium hexafluoroantimonate (purchased from Wuhan Shuer Biotechnology Co., Ltd.), and 3 kg of wetting agent (BYK-DYNWET 800N, purchased from Guangzhou Si Tuyuan Chemical Co., Ltd.) are mixed evenly at 50° C., filtered, sprayed and atomized, and simultaneously cured by electron beam radiation. After being cured into spheres, the mixture falls into 1,1,2,2-tetrabromoethane, and is collected and dried to obtain the obtained product.

[0048] The process conditions of electron beam radiation curing are: nitrogen concentration 200 mg / L, temperature 15°C, and electron beam dose 50 kGy.

[0049] In step (2), the process conditions for heating polymerization are: polymerization reaction at 65° C. for 40 minutes.

[0050] In step (3), the process conditions for heating and curing are: standing at 70°C for 2 hours and standing at 110°C for 2 hours.

[0051] Embodiment 2:

[0052] A method for preparing an antibacterial and heat-resistant acrylic sheet, the specific steps are as follows:

[0053] (1) adding 1 kg of polyether diol, 1.5 kg of diisocyanate, 0.4 kg of dihydroxymethyl propionic acid, 0.002 kg of dibutyltin dilaurate and 1.5 kg of methyl methacrylate to a reactor, reacting at 80° C. for 6 hours to obtain a polyurethane prepolymer solution; then adding 1 kg of hydroxypropyl methacrylate to the polyurethane prepolymer solution, reacting at 80° C. for 4 hours to obtain a double-bond terminated polyurethane solution, continuing to add 0.3 kg of a neutralizer, 0.02 kg of an initiator and 0.04 kg of an emulsifier, stirring and mixing, adding 5 kg of an aqueous silver nitrate solution, 0.2 kg of a three-dimensional porous graphene and 0.5 kg of acrylic microspheres, stirring and emulsifying to obtain a premixed emulsion, passing nitrogen gas into the premixed emulsion, stirring, polymerizing and reducing to obtain a composite emulsion;

[0054] (2) then 100 kg of methyl methacrylate, 4 kg of the composite emulsion, and 0.04 kg of azobisisobutyronitrile were fully mixed and heated for polymerization to obtain a prepolymer slurry;

[0055] (3) Finally, the prepolymer slurry is fully mixed with 0.03 kg of azobisisobutyronitrile, poured into a mold, heated and cured, naturally cooled to room temperature (25° C.), and demolded to obtain the antibacterial and heat-resistant acrylic sheet.

[0056] Wherein, in step (1), the polyether diol is polyether 204, and the diisocyanate is 4,4'-dicyclohexylmethane diisocyanate, both of which are purchased from Green Union (Jining) Chemical Technology Co., Ltd.

[0057] In step (1), the process conditions for stirring and emulsifying are: stirring and emulsifying at 3000 r / min for 1 to 2 hours.

[0058] In step (1), the process conditions for stirring polymerization and reduction are: stirring and heating to 55° C. at 3000 r / min, keeping the temperature and stirring for 4 to 5 hours, and naturally cooling to room temperature (25° C.) to obtain the composite emulsion.

[0059] In step (1), the neutralizer is sodium hydroxide, the initiator is potassium persulfate, the emulsifier is Span 60, and the concentration of the silver nitrate aqueous solution is 0.4 mol / L.

[0060] In step (1), the three-dimensional porous graphene is prepared by the following method: firstly dissolving graphene oxide in water to obtain a graphene oxide aqueous solution with a concentration of 5 g / L, then adding polystyrene microspheres (purchased from Dongguan Mingyuan Plastic Co., Ltd., with a particle size of 100 nm) to the graphene oxide aqueous solution, treating with 500W ultrasonic oscillation for 3 hours, adjusting the pH to 8 with 1 mol / L sodium hydroxide solution, filtering out the solid, drying, and calcining at 800°C for 3 hours to achieve decomposition of the polystyrene microspheres and reduction of the graphene oxide, thereby obtaining the three-dimensional porous graphene; wherein the amount of the polystyrene microspheres is 3 times the mass of the graphene oxide.

[0061] In step (1), the acrylic microspheres are prepared by the following method: 18 kg of ethoxylated bisphenol A dimethacrylate (purchased from Wuhan Tosoh Chemical Technology Co., Ltd.), 45 kg of methyl methacrylate, 45 kg of Japanese refined wax (EP-1400, Tianjin Hengsheng Xinyuan International Trade Co., Ltd.), 3 kg of bis(4-dodecylbenzene) iodonium hexafluoroantimonate (purchased from Wuhan Shuer Biotechnology Co., Ltd.), and 5 kg of wetting agent (BYK-DYNWET 800N, purchased from Guangzhou Si Tuyuan Chemical Co., Ltd.) are mixed uniformly at 60° C., filtered, sprayed and atomized, and simultaneously cured by electron beam radiation. After being cured into spheres, the mixture falls into 1,1,2,2-tetrabromoethane, and is collected and dried to obtain the obtained product.

[0062] The process conditions of electron beam radiation curing are: nitrogen concentration 300 mg / L, temperature 20°C, and electron beam dose 60 kGy.

[0063] In step (2), the process conditions for heating polymerization are: polymerization reaction at 75° C. for 50 minutes.

[0064] In step (3), the process conditions for heating and curing are: standing at 75°C for 3 hours and standing at 120°C for 3 hours.

[0065] Embodiment 3:

[0066] A method for preparing an antibacterial and heat-resistant acrylic sheet, the specific steps are as follows:

[0067] (1) 1 kg of polyether diol, 1.2 kg of diisocyanate, 0.4 kg of dihydroxymethyl propionic acid, 0.001 kg of dibutyltin dilaurate and 1.5 kg of methyl methacrylate were added to a reaction kettle, and reacted at 70° C. for 6 hours to obtain a polyurethane prepolymer solution; then 1 kg of hydroxypropyl methacrylate was added to the polyurethane prepolymer solution, and reacted at 70° C. for 4 hours to obtain a double-bond terminated polyurethane solution, and 0.2 kg of a neutralizer, 0.02 kg of an initiator and 0.03 kg of an emulsifier were added, and stirred to mix, and 5 kg of silver nitrate aqueous solution, 0.1 kg of three-dimensional porous graphene and 0.5 kg of acrylic microspheres were added, and stirred and emulsified to obtain a premixed emulsion, and nitrogen was passed into the premixed emulsion, and polymerization and reduction were performed under stirring to obtain a composite emulsion;

[0068] (2) then 100 kg of methyl methacrylate, 3 kg of the composite emulsion, and 0.04 kg of azobisisobutyronitrile were fully mixed and heated for polymerization to obtain a prepolymer slurry;

[0069] (3) Finally, the prepolymer slurry is fully mixed with 0.02 kg of azobisisobutyronitrile, poured into a mold, heated and cured, naturally cooled to room temperature (25° C.), and demolded to obtain the antibacterial and heat-resistant acrylic sheet.

[0070] Wherein, in step (1), the polyether diol is polyether 204, and the diisocyanate is 4,4'-dicyclohexylmethane diisocyanate, both of which are purchased from Green Union (Jining) Chemical Technology Co., Ltd.

[0071] In step (1), the process conditions for stirring and emulsifying are: stirring and emulsifying at 3000 r / min for 1 hour.

[0072] In step (1), the process conditions for stirring polymerization and reduction are: stirring and heating to 50° C. at 3000 r / min, keeping the temperature and stirring for 5 hours, and naturally cooling to room temperature (25° C.) to obtain the composite emulsion.

[0073] In step (1), the neutralizer is potassium hydroxide, the initiator is ammonium persulfate, the emulsifier is Span 80, and the concentration of the silver nitrate aqueous solution is 0.2 mol / L.

[0074] In step (1), the three-dimensional porous graphene is prepared by the following method: firstly dissolving graphene oxide in water to obtain a graphene oxide aqueous solution with a concentration of 5 g / L, then adding polystyrene microspheres (purchased from Dongguan Mingyuan Plastic Co., Ltd., with a particle size of 100 nm) to the graphene oxide aqueous solution, treating with 500W ultrasonic oscillation for 3 hours, adjusting the pH to 8 with 1 mol / L sodium hydroxide solution, filtering out the solid, drying, and calcining at 800°C for 2 hours to achieve decomposition of the polystyrene microspheres and reduction of the graphene oxide, thereby obtaining the three-dimensional porous graphene; wherein the amount of the polystyrene microspheres is 3 times the mass of the graphene oxide.

[0075] In step (1), the acrylic microspheres are prepared by the following method: 18 kg of ethoxylated bisphenol A dimethacrylate (purchased from Wuhan Tosoh Chemical Technology Co., Ltd.), 40 kg of methyl methacrylate, 45 kg of Japanese refined wax (EP-1400, Tianjin Hengsheng Xinyuan International Trade Co., Ltd.), 2 kg of bis(4-dodecylbenzene) iodonium hexafluoroantimonate (purchased from Wuhan Shuer Biotechnology Co., Ltd.), and 5 kg of wetting agent (BYK-DYNWET 800N, purchased from Guangzhou Si Tuyuan Chemical Co., Ltd.) are mixed uniformly at 50° C., filtered, sprayed and atomized, and simultaneously cured by electron beam radiation. After being cured into spheres, the mixture falls into 1,1,2,2-tetrabromoethane, and is collected and dried to obtain the obtained product.

[0076] The process conditions of electron beam radiation curing are: nitrogen concentration 300 mg / L, temperature 15°C, and electron beam dose 60 kGy.

[0077] In step (2), the process conditions for heating polymerization are: polymerization reaction at 65° C. for 50 minutes.

[0078] In step (3), the process conditions for heating and curing are: standing at 70°C for 3 hours and standing at 110°C for 3 hours.

[0079] Embodiment 4:

[0080] A method for preparing an antibacterial and heat-resistant acrylic sheet, the specific steps are as follows:

[0081] (1) 1 kg of polyether diol, 1.4 kg of diisocyanate, 0.35 kg of dihydroxymethyl propionic acid, 0.0015 kg of dibutyltin dilaurate and 1.3 kg of methyl methacrylate were added to a reaction kettle, and reacted at 75° C. for 5.5 hours to obtain a polyurethane prepolymer solution; then 1 kg of hydroxypropyl methacrylate was added to the polyurethane prepolymer solution, and reacted at 75° C. for 3.5 hours to obtain a double-bond terminated polyurethane solution, and 0.25 kg of a neutralizer, 0.015 kg of an initiator and 0.035 kg of an emulsifier were added, and stirred to mix, and 4.5 kg of a silver nitrate aqueous solution, 0.15 kg of a three-dimensional porous graphene and 0.45 kg of acrylic microspheres were added, and stirred and emulsified to obtain a premixed emulsion, and nitrogen was passed into the premixed emulsion, and stirred, polymerized and reduced to obtain a composite emulsion;

[0082] (2) then 100 kg of methyl methacrylate, 3.5 kg of the composite emulsion, and 0.035 kg of azobisisobutyronitrile were fully mixed and heated for polymerization to obtain a prepolymer slurry;

[0083] (3) Finally, the prepolymer slurry is fully mixed with 0.025 kg of azobisisobutyronitrile, poured into a mold, heated and cured, naturally cooled to room temperature (25° C.), and demolded to obtain the antibacterial and heat-resistant acrylic sheet.

[0084] Wherein, in step (1), the polyether diol is polyether 204, and the diisocyanate is 4,4'-dicyclohexylmethane diisocyanate, both of which are purchased from Green Union (Jining) Chemical Technology Co., Ltd.

[0085] In step (1), the process conditions for stirring and emulsifying are: stirring and emulsifying at 3000 r / min for 1.5 hours.

[0086] In step (1), the process conditions for stirring polymerization and reduction are: stirring and heating to 52° C. at 3000 r / min, keeping the temperature and stirring for 4 to 5 hours, and naturally cooling to room temperature (25° C.) to obtain the composite emulsion.

[0087] In step (1), the neutralizer is sodium hydroxide, the initiator is potassium persulfate, the emulsifier is Span 60, and the concentration of the silver nitrate aqueous solution is 0.3 mol / L.

[0088] In step (1), the three-dimensional porous graphene is prepared by the following method: firstly dissolving graphene oxide in water to obtain a graphene oxide aqueous solution with a concentration of 5 g / L, then adding polystyrene microspheres (purchased from Dongguan Mingyuan Plastic Co., Ltd., with a particle size of 100 nm) to the graphene oxide aqueous solution, treating with 500W ultrasonic oscillation for 3 hours, adjusting the pH to 8 with 1 mol / L sodium hydroxide solution, filtering out the solid, drying, and calcining at 800°C for 2.5 hours to achieve decomposition of the polystyrene microspheres and reduction of the graphene oxide, thereby obtaining the three-dimensional porous graphene; wherein the amount of the polystyrene microspheres is 3 times the mass of the graphene oxide.

[0089] In step (1), the acrylic microspheres are prepared by the following method: 17 kg of ethoxylated bisphenol A dimethacrylate (purchased from Wuhan Tosoh Chemical Technology Co., Ltd.), 42 kg of methyl methacrylate, 42 kg of Japanese refined wax (EP-1400, Tianjin Hengsheng Xinyuan International Trade Co., Ltd.), 2.5 kg of bis(4-dodecylbenzene) iodonium hexafluoroantimonate (purchased from Wuhan Shuer Biotechnology Co., Ltd.), and 4 kg of wetting agent (BYK-DYNWET 800N, purchased from Guangzhou Si Tuyuan Chemical Co., Ltd.) are mixed evenly at 55° C., filtered, sprayed and atomized, and simultaneously cured by electron beam radiation. After being cured into spheres, the mixture falls into 1,1,2,2-tetrabromoethane, and is collected and dried to obtain the obtained product.

[0090] The process conditions of electron beam radiation curing are: nitrogen concentration 300 mg / L, temperature 18°C, and electron beam dose 55 kGy.

[0091] In step (2), the process conditions for heating polymerization are: polymerization reaction at 70° C. for 45 minutes.

[0092] In step (3), the process conditions for heat curing are: standing at 72°C for 3 hours and standing at 115°C for 2.5 hours.

[0093] Comparative Example 1

[0094] A method for preparing an acrylic sheet, the specific steps are as follows:

[0095] (1) 1 kg of polyether diol, 1.2 kg of diisocyanate, 0.3 kg of dimethylol propionic acid, 0.001 kg of dibutyltin dilaurate and 1.2 kg of methyl methacrylate were added to a reaction kettle, and reacted at 70° C. for 5 hours to obtain a polyurethane prepolymer solution; then 1 kg of hydroxypropyl methacrylate was added to the polyurethane prepolymer solution, and reacted at 70° C. for 3 hours to obtain a double-bond terminated polyurethane solution, and 0.2 kg of a neutralizer, 0.01 kg of an initiator and 0.03 kg of an emulsifier were added, and stirred to mix, and 4 kg of a silver nitrate aqueous solution and 0.4 kg of acrylic microspheres were added, and stirred and emulsified to obtain a premixed emulsion, and nitrogen was passed through the premixed emulsion, and stirred, polymerized and reduced to obtain a composite emulsion;

[0096] (2) then 100 kg of methyl methacrylate, 3 kg of the composite emulsion, and 0.03 kg of azobisisobutyronitrile were fully mixed and heated for polymerization to obtain a prepolymer slurry;

[0097] (3) Finally, the prepolymer slurry is fully mixed with 0.02 kg of azobisisobutyronitrile, poured into a mold, heated and cured, naturally cooled to room temperature (25° C.), and demolded to obtain the acrylic sheet.

[0098] Wherein, in step (1), the polyether diol is polyether 204, and the diisocyanate is 4,4'-dicyclohexylmethane diisocyanate, both of which are purchased from Green Union (Jining) Chemical Technology Co., Ltd.

[0099] In step (1), the process conditions for stirring and emulsifying are: stirring and emulsifying at 2000 r / min for 1 hour.

[0100] In step (1), the process conditions for stirring polymerization and reduction are: stirring and heating to 50° C. at 2000 r / min, keeping the temperature and stirring for 4 hours, and naturally cooling to room temperature (25° C.) to obtain the composite emulsion.

[0101] In step (1), the neutralizing agent is triethylamine, the initiator is ammonium persulfate, the emulsifier is Span 80, and the concentration of the silver nitrate aqueous solution is 0.2 mol / L.

[0102] In step (1), the acrylic microspheres are prepared by the following method: 15 kg of ethoxylated bisphenol A dimethacrylate (purchased from Wuhan Tosoh Chemical Technology Co., Ltd.), 40 kg of methyl methacrylate, 40 kg of Japanese refined wax (EP-1400, Tianjin Hengsheng Xinyuan International Trade Co., Ltd.), 2 kg of bis(4-dodecylbenzene) iodonium hexafluoroantimonate (purchased from Wuhan Shuer Biotechnology Co., Ltd.), and 3 kg of wetting agent (BYK-DYNWET 800N, purchased from Guangzhou Si Tuyuan Chemical Co., Ltd.) are mixed evenly at 50° C., filtered, sprayed and atomized, and simultaneously cured by electron beam radiation. After being cured into spheres, the mixture falls into 1,1,2,2-tetrabromoethane, and is collected and dried to obtain the obtained product.

[0103] The process conditions of electron beam radiation curing are: nitrogen concentration 200 mg / L, temperature 15°C, and electron beam dose 50 kGy.

[0104] In step (2), the process conditions for heating polymerization are: polymerization reaction at 65° C. for 40 minutes.

[0105] In step (3), the process conditions for heating and curing are: standing at 70°C for 2 hours and standing at 110°C for 2 hours.

[0106] Comparative Example 2

[0107] A method for preparing an acrylic sheet, the specific steps are as follows:

[0108] (1) 1 kg of polyether diol, 1.2 kg of diisocyanate, 0.3 kg of dimethylol propionic acid, 0.001 kg of dibutyltin dilaurate and 1.2 kg of methyl methacrylate were added to a reaction kettle, and reacted at 70° C. for 5 hours to obtain a polyurethane prepolymer solution; then 1 kg of hydroxypropyl methacrylate was added to the polyurethane prepolymer solution, and reacted at 70° C. for 3 hours to obtain a double-bond terminated polyurethane solution, and 0.2 kg of a neutralizer, 0.01 kg of an initiator and 0.03 kg of an emulsifier were added, and stirred to mix, and 4 kg of an aqueous silver nitrate solution and 0.1 kg of three-dimensional porous graphene were added, and stirred and emulsified to obtain a premixed emulsion, and nitrogen was passed into the premixed emulsion, and stirred for polymerization and reduction to obtain a composite emulsion;

[0109] (2) then 100 kg of methyl methacrylate, 3 kg of the composite emulsion, and 0.03 kg of azobisisobutyronitrile were fully mixed and heated for polymerization to obtain a prepolymer slurry;

[0110] (3) Finally, the prepolymer slurry is fully mixed with 0.02 kg of azobisisobutyronitrile, poured into a mold, heated and cured, naturally cooled to room temperature (25° C.), and demolded to obtain the acrylic sheet.

[0111] Wherein, in step (1), the polyether diol is polyether 204, and the diisocyanate is 4,4'-dicyclohexylmethane diisocyanate, both of which are purchased from Green Union (Jining) Chemical Technology Co., Ltd.

[0112] In step (1), the process conditions for stirring and emulsifying are: stirring and emulsifying at 2000 r / min for 1 hour.

[0113] In step (1), the process conditions for stirring polymerization and reduction are: stirring and heating to 50° C. at 2000 r / min, keeping the temperature and stirring for 4 hours, and naturally cooling to room temperature (25° C.) to obtain the composite emulsion.

[0114] In step (1), the neutralizing agent is triethylamine, the initiator is ammonium persulfate, the emulsifier is Span 80, and the concentration of the silver nitrate aqueous solution is 0.2 mol / L.

[0115] In step (1), the three-dimensional porous graphene is prepared by the following method: firstly dissolving graphene oxide in water to obtain a graphene oxide aqueous solution with a concentration of 5 g / L, then adding polystyrene microspheres (purchased from Dongguan Mingyuan Plastic Co., Ltd., with a particle size of 100 nm) to the graphene oxide aqueous solution, treating with 400W ultrasonic oscillation for 3 hours, adjusting the pH to 8 with 1 mol / L sodium hydroxide solution, filtering out the solid, drying, and calcining at 800°C for 2 hours to achieve decomposition of the polystyrene microspheres and reduction of the graphene oxide, thereby obtaining the three-dimensional porous graphene; wherein the amount of the polystyrene microspheres is 3 times the mass of the graphene oxide.

[0116] In step (2), the process conditions for heating polymerization are: polymerization reaction at 65° C. for 40 minutes.

[0117] In step (3), the process conditions for heating and curing are: standing at 70°C for 2 hours and standing at 110°C for 2 hours.

[0118] Test example

[0119] The antibacterial property and heat resistance of the acrylic sheets obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were investigated respectively, and the specific methods are as follows:

[0120] 1. Antibacterial property: Refer to the sample preparation and bacterial inoculation method described in GB / T 31402-2015 "Test method for antibacterial performance of plastic surfaces" to test the bactericidal rate of acrylic sheet against Staphylococcus aureus ATCC 6538P and Escherichia coli ATCC 8739.

[0121] 2. Heat resistance: Cut 3cm×3cm acrylic sheets as samples, boil the samples in a water bath at 80℃ for 480 hours, and test the color difference ΔE of the samples. Among them, ΔL, Δa, and Δb are the differences in lightness L and chromaticity index a and b between the samples before and after boiling, respectively.

[0122] 3. Impact resistance: Refer to GB / T 7134-2008 "Casting Industrial Organic Glass Sheet", the thickness of the sheet is 2mm, and the simply supported beam unnotched impact strength of the sheet is tested.

[0123] The test results are shown in Table 1.

[0124] Table 1. Performance test of acrylic sheet

[0125]

[0126] As can be seen from Table 1, the acrylic sheets obtained in Examples 1 to 4 have a high sterilization rate and a small color difference after long-term contact with hot water, indicating good heat resistance and good impact resistance, which shows that the present invention improves the antibacterial and heat resistance without damaging the mechanical properties of the product.

[0127] In Comparative Example 1, the three-dimensional porous graphene is omitted, and in Comparative Example 2, the acrylic microspheres are omitted, and the antibacterial property, heat resistance and impact resistance are obviously deteriorated, indicating that the three-dimensional porous graphene, acrylic microspheres and the like of the present invention synergistically enhance the antibacterial property and heat resistance while also improving the mechanical properties of the product to a certain extent.

[0128] Although the above describes the specific implementation methods of the present invention, it does not limit the scope of protection of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. A method for preparing an antibacterial and heat-resistant acrylic sheet, characterized in that: The specific steps are as follows: (1) firstly prepare a polyurethane prepolymer solution using polyether diol, diisocyanate and dimethylol propionic acid as raw materials, then add hydroxypropyl methacrylate to react to obtain a double-bond terminated polyurethane solution, continue to add a neutralizer, an initiator and an emulsifier, stir and mix, add a silver nitrate aqueous solution, three-dimensional porous graphene and acrylic microspheres, stir and emulsify to obtain a premixed emulsion, pass nitrogen into the premixed emulsion, stir and polymerize and reduce to obtain a composite emulsion; (2) then fully mixing methyl methacrylate, the composite emulsion, and azobisisobutyronitrile, and heating and polymerizing to obtain a prepolymer slurry; (3) Finally, the prepolymer slurry is fully mixed with azobisisobutyronitrile, poured into a mold, heated and cured, naturally cooled to room temperature, and demolded to obtain the antibacterial and heat-resistant acrylic sheet.

2. The preparation method according to claim 1, characterized in that: In step (1), the preparation method of the polyurethane prepolymer solution is as follows: polyether diol, diisocyanate, dimethylol propionic acid, dibutyl tin dilaurate and methyl methacrylate are added into a reaction kettle, and reacted at 70-80° C. for 5-6 hours to obtain the polyurethane prepolymer solution.

3. The preparation method according to claim 1, characterized in that: In step (1), hydroxypropyl methacrylate and polyether diol are of equal mass, and the process conditions for preparing a double-bond terminated polyurethane solution are: reacting at 70-80° C. for 3-4 hours.

4. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of polyether diol, neutralizer, initiator, emulsifier, silver nitrate aqueous solution, three-dimensional porous graphene, and acrylic microspheres is 10:2-3:0.1-0.2:0.3-0.4:40-50:1-2:4-5.

5. The preparation method according to claim 1, characterized in that: In step (1), the process conditions for stirring and emulsifying are: stirring and emulsifying at 2000-3000 r / min for 1-2 hours.

6. The preparation method according to claim 1, characterized in that: In step (1), the process conditions for stirring polymerization and reduction are: stirring and heating to 50-55° C. at 2000-3000 r / min, keeping the temperature and stirring for 4-5 hours, and naturally cooling to room temperature to obtain the composite emulsion.

7. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of methyl methacrylate, composite emulsion and azobisisobutyronitrile is 100:3-4:0.03-0.04; The process conditions of the heating polymerization are: polymerization reaction at 65-75°C for 40-50 minutes.

8. The preparation method according to claim 1, characterized in that: In step (3), the amount of azobisisobutyronitrile used is 0.02 to 0.03% of the mass of methyl methacrylate in step (2); The process conditions for heat curing are: standing at 70-75°C for 2-3 hours, and standing at 110-120°C for 2-3 hours.

9. An antibacterial and heat-resistant acrylic sheet, characterized in that: The invention is obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the antibacterial and heat-resistant acrylic sheet according to claim 9 in bathtub processing.

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