A method for processing a low odor antimicrobial material

Abstract

The application discloses a processing method of low-odor antibacterial material and belongs to the technical field of low-odor antibacterial material, and comprises the following steps: in the first step, polystyrene resin, an odor adsorbent, an antibacterial agent and a compounded antioxidant are premixed, then the premixed material is added into a hopper and is conveyed into a double-screw extruder through a feeding screw; in the second step, a high-temperature-resistant surfactant is mixed with water to obtain a mixed solution, and the mixed solution is added into the double-screw extruder through a water injection port and is mixed with the premixed material; in the third step, the molten material reaching an exhaust section is vacuumized, then is extruded and granulated through an extrusion section to obtain the low-odor antibacterial material; according to the combined action of adsorption and release, the application can reduce the generation of small-molecule volatile substances and the odor of the material to the maximum extent; in addition, the antibacterial agent has good dispersing effect and can better play the antibacterial role.

Description

Technical Field

[0001] This invention belongs to the technical field of low-odor antibacterial materials, specifically relating to a processing method for low-odor antibacterial materials. Background Technology

[0002] The refrigerator's storage compartment is primarily composed of various plastics, including general-purpose polystyrene (GPPS), high-impact polystyrene (HIPS), and expandable polystyrene (EPS). During high-temperature processing, styrene monomers, dimers, and trimers undergo oxidative degradation, with small molecular chains diffusing to the polymer surface. When heated again, these small molecular chains volatilize and undergo oxidative pyrolysis, producing aldehydes, ketones, benzene, and benzene derivatives. Some materials incorporate pentane-based foaming agents during manufacturing, resulting in relatively lower density after molding and a greater susceptibility to volatile organic compound (VOC) formation.

[0003] n-Pentane and isopentane are the main sources of odor in refrigerators. During the synthesis and processing of polystyrene-based materials, plasticizers, dispersants, stabilizers, antibacterial agents, and other plastic additives are added, leaving residues and releasing high levels of volatile organic compounds (VOCs) such as benzene, toluene, xylene, and styrene. High levels of these VOCs can damage sensory nerves such as vision and hearing, and long-term exposure can even cause nervousness or depression. VOCs can harm the liver, kidneys, brain, and nervous system, and may even lead to blood problems, such as leukemia and other serious diseases. Furthermore, harmful substances produced during refrigerator use can diffuse onto the surface and inside of food, posing a threat to dietary health. Therefore, it is necessary to provide a processing method for low-odor, antibacterial materials. Summary of the Invention

[0004] The purpose of this invention is to provide a processing method for a low-odor antibacterial material to solve the problems in the prior art.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for processing a low-odor antibacterial material includes the following steps:

[0007] The first step is to add polystyrene resin, odor absorbent, antibacterial agent and compound antioxidant into a high-speed mixer for premixing to obtain premixed material. Then, the premixed material is added to the hopper and conveyed to the twin-screw extruder through the feeding screw.

[0008] The second step is to mix the high-temperature resistant surfactant with water to obtain a mixture. The mixture is then added to a twin-screw extruder through a water inlet. The mixture and the premixed material are then kneaded in the twin-screw extruder. The high-temperature resistant surfactant can promote the fusion of water vapor and small molecule harmful substances, extract small molecule volatiles more efficiently, and improve their removal efficiency.

[0009] The third step is to vacuum the molten material that reaches the exhaust section, and then extrude and granulate it through the extrusion section to obtain a low-odor antibacterial material.

[0010] Furthermore, the mass ratio of the polystyrene resin, odor absorbent, antibacterial agent, and compound antioxidant is 100:0.5-2:2-3:0.1-0.3; the polystyrene resin is general-purpose polystyrene (GPPS) or impact-resistant polystyrene (HIPS).

[0011] Furthermore, the odor adsorbent is prepared by the following steps:

[0012] A porous material is added to an ultrasonic cleaner, followed by an acid solution. The ultrasonic cleaner is set to 600-800W. After ultrasonic vibration and acid soaking for 5-10 minutes, the material is filtered, washed, and dried to obtain an odor adsorbent. The porous material is one of zeolite, diatomaceous earth, and montmorillonite. This invention uses 37% hydrochloric acid as the acid solution. The ultrasonic vibration and acid soaking process removes impurities from the porous material's pores, resulting in a superior microporous morphology and thus better adsorption performance. This allows the material to anchor small molecules in the resin material, reducing subsequent odor leakage.

[0013] Furthermore, the antibacterial agent is prepared by the following steps:

[0014] Tetraphenylbenzyltriethoxysilane was added to an aqueous ethanol solution and the temperature was set to 70°C. Ammonia was added to adjust the pH to 8. Porous silver-loaded silica was added, and the mixture was stirred for 30 minutes. After ultrasonic dispersion, the mixture was filtered, washed with anhydrous ethanol, dried, crushed, and passed through a 300-mesh sieve to obtain the antibacterial agent.

[0015] Porous silver-loaded silica also has a porous structure. In addition to being able to load silver ions with antibacterial properties, these pores can also adsorb a small amount of small molecules, enabling the prepared material to achieve a better low-odor effect. Surface treatment of porous silver-loaded silica with tetraphenylbenzyltriethoxysilane can prevent the aggregation of porous silver-loaded silica and improve its dispersion effect with resin materials.

[0016] Furthermore, the ratio of tetraphenylbenzyltriethoxysilane, aqueous ethanol solution, and porous silver-loaded silica is 2 mL: 25 mL: 10 g; the volume fraction of the aqueous ethanol solution is 80%.

[0017] Furthermore, the porous silver-loaded silica is prepared by the following steps:

[0018] Step A1: Add polyethylene oxide and methyl orthosilicate to a 0.01 mol / L hydrochloric acid solution at a molar ratio of 0.002:1, add propylene oxide, set the temperature to 40℃, and age for 3 days. Wash the resulting gel with anhydrous ethanol, dry it, and then pulverize it through a 200-mesh sieve to obtain porous silica. The molecular weight of polyethylene oxide is 10000. The ratio of polyethylene oxide, hydrochloric acid solution, and propylene oxide is 1 g: 0.01 g: 10 mL.

[0019] Step A2: Mix porous silica and deionized water, stir to disperse, add 0.3 mol / L silver ammonia solution, stir for 3 hours, centrifuge to remove the upper liquid, add 0.5 mol / L glutaraldehyde solution and stir until the color turns purple-black. After centrifugation, washing with water and drying, porous silver-loaded silica is obtained. The ratio of porous silica, deionized water, silver ammonia solution and glutaraldehyde solution is 2 g: 100 mL: 150 mL: 20 mL.

[0020] Furthermore, the compound antioxidant is obtained by compounding antioxidant 168 and antioxidant 1010 in a mass ratio of 1:1.

[0021] Furthermore, the premixing temperature in the first step is 90-100℃, and the premixing time is 3-5 minutes.

[0022] Furthermore, in the second step, the amount of the mixture is 2-5% of the total mass of the premixed materials; the mass percentage of the high-temperature resistant surfactant in the mixture is 3-5%.

[0023] Furthermore, the high-temperature resistant surfactant is prepared by the following steps:

[0024] Under nitrogen protection, vinylsiloxane and L-cysteine ​​were added to a mixture of tetrahydrofuran and water, followed by the addition of a photocatalyst. The mixture was stirred for 10-15 minutes under 365 nm ultraviolet light irradiation. After stirring, the excess solvent was removed by rotary evaporation, followed by washing with n-hexane to obtain a high-temperature resistant surfactant. The molar ratio of vinylsiloxane, L-cysteine, tetrahydrofuran, water, and photocatalyst was 0.01 mol: 0.01 mol: 40 mL: 10 mL: 0.1 g. The photocatalyst was α,α-dimethoxy-α-phenylacetophenone.

[0025] This high-temperature resistant surfactant belongs to the amino acid surfactant class and has excellent surface properties and environmental friendliness. Using L-cysteine ​​as a raw material, combined with the thermal stability of vinylsiloxane, this invention improves the adaptability of the surfactant.

[0026] Furthermore, the vinylsiloxane is one of vinyltris(trimethylsiloxy)silane and vinyltris(dimethylsiloxane)silane.

[0027] Furthermore, the twin-screw extruder has an aspect ratio of 56:1. A large aspect ratio in a twin-screw extruder provides ample screw assembly margin, ensuring thorough mixing while offering better dispersion channels. The twin-screw extruder has a mixing temperature of 170-190℃ and a mixing time of no less than 2 minutes. At relatively low temperatures, the thermal degradation of resins and additives is reduced, decreasing the generation of small-molecule volatiles. Under longer mixing times, water vapor can better extract small-molecule volatiles from the molten material, which is more conducive to the subsequent removal of volatile organic compounds during vacuuming.

[0028] Furthermore, the vacuum level of the vacuum pump is -0.09 MPa, which is beneficial for better removal of water vapor from the extracted small molecule volatiles.

[0029] The beneficial effects of this invention are:

[0030] This invention preheats and premixes the raw materials, ensuring uniform mixing while simultaneously removing some volatiles, thus reducing the total amount of volatiles. Furthermore, by adding a mixture of high-temperature resistant surfactant and water to a twin-screw extruder and mixing it with the premixed materials, this invention promotes the fusion of water vapor and small-molecule harmful substances, resulting in more efficient extraction and removal of small-molecule volatiles. Simultaneously, the addition of an odor adsorbent to the raw materials anchors small molecules in the resin material, reducing subsequent odor leakage. This combined action of adsorption and removal minimizes the generation of small-molecule volatiles and reduces the material's odor.

[0031] This invention uses a twin-screw extruder with a large length-to-diameter ratio during processing, which ensures thorough mixing while providing better dispersion channels. This invention sets a lower mixing temperature and a longer mixing time, which can reduce the thermal degradation of resins and additives, reduce the generation of small molecule volatiles, and at the same time, water vapor can better extract small molecule volatiles from the molten material, which is more conducive to the removal of organic volatiles during subsequent vacuuming.

[0032] This invention uses tetraphenylbenzyltriethoxysilane to surface-treat porous silver-loaded silica, which can prevent the aggregation of porous silver-loaded silica, improve its dispersion effect with resin materials, and better exert the antibacterial effect of silver ions. Moreover, the porous silver-loaded silica also has a porous structure. In addition to loading silver ions with antibacterial effect, these pores can also adsorb a small amount of small molecules, so that the prepared material can achieve a better low-odor effect. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] The odor adsorbent in this embodiment is prepared through the following steps:

[0036] Zeolite passing through 800 mesh was added to an ultrasonic cleaner, followed by hydrochloric acid with a mass fraction of 37%. The ultrasonic cleaner was set to 800W, and after ultrasonic vibration and acid soaking for 5 minutes, the odor adsorbent was obtained by filtration, washing, and drying.

[0037] Example 2

[0038] The odor adsorbent in this embodiment is prepared through the following steps:

[0039] Diatomaceous earth passing through 300 mesh was added to an ultrasonic cleaner, followed by hydrochloric acid with a mass fraction of 37%. The ultrasonic cleaner was set to a power of 700W, and after ultrasonic vibration and acid soaking for 8 minutes, the odor adsorbent was obtained after filtration, washing, and drying.

[0040] Example 3

[0041] The odor adsorbent in this embodiment is prepared through the following steps:

[0042] Montmorillonite with a mesh size of 200 was added to an ultrasonic cleaner, followed by hydrochloric acid with a mass fraction of 37%. The ultrasonic cleaner was set to a power of 600W. After ultrasonic vibration and acid soaking for 10 minutes, the odor adsorbent was obtained by filtration, washing and drying.

[0043] Comparative Example 1

[0044] Compared with Example 2, this comparative example did not undergo ultrasonic vibration acid leaching treatment, and directly used diatomaceous earth with a mesh size of 200 as the odor adsorbent.

[0045] Example 4

[0046] The antibacterial agent in this embodiment is prepared through the following steps:

[0047] Polyethylene oxide (10000) and methyl orthosilicate were added to a 0.01 mol / L hydrochloric acid solution at a molar ratio of 0.002:1. Propylene oxide was added, and the temperature was set at 40℃. The ratio of polyethylene oxide, hydrochloric acid solution, and propylene oxide was 1 g:0.01 g:10 mL. After aging for 3 days, the resulting gel was washed with anhydrous ethanol, dried, and pulverized through a 200-mesh sieve to obtain porous silica. The porous silica was then mixed with deionized water, stirred to disperse, and 0.3 mol / L silver ammonia solution was added. After stirring for 3 hours, the supernatant was removed by centrifugation. 0.5 mol / L glutaraldehyde solution was added and stirred until the color turned purplish-black. The ratio of porous silica, deionized water, silver ammonia solution, and glutaraldehyde solution was 2 g:100 mL:150 mL:20 mL. After centrifugation, washing, and drying, porous silver-loaded silica was obtained.

[0048] According to the ratio of tetraphenylbenzyltriethoxysilane, aqueous ethanol solution, and porous silver-loaded silica as 2mL:25mL:10g, tetraphenylbenzyltriethoxysilane was added to an 80% (v / v) aqueous ethanol solution. At 70℃, ammonia was added to adjust the pH to 8. The porous silver-loaded silica was then added, stirred for 30 minutes, and ultrasonically dispersed. After filtration, washing with anhydrous ethanol, drying, crushing, and passing through a 300-mesh sieve, the antibacterial agent was obtained.

[0049] Comparative Example 2

[0050] Compared with Example 4, this comparative example directly uses porous silver-loaded silica as an antibacterial agent.

[0051] Example 5

[0052] The high-temperature resistant surfactant in this embodiment is prepared through the following steps:

[0053] Under nitrogen protection, vinyltris(trimethylsiloxy)silane and L-cysteine ​​were added to a mixture of tetrahydrofuran and water, followed by the addition of α,α-dimethoxy-α-phenylacetophenone. The molar ratio of vinyltris(trimethylsiloxy)silane, L-cysteine, tetrahydrofuran, water, and α,α-dimethoxy-α-phenylacetophenone was 0.01 mol: 0.01 mol: 40 mL: 10 mL: 0.1 g. The mixture was stirred for 10 min under 365 nm ultraviolet light irradiation. After stirring, the excess solvent was removed by rotary evaporation, followed by washing with n-hexane to obtain a high-temperature resistant surfactant.

[0054] Example 6

[0055] The high-temperature resistant surfactant in this embodiment is prepared through the following steps:

[0056] Under nitrogen protection, vinyltris(dimethylsiloxane)silane and L-cysteine ​​were added to a mixture of tetrahydrofuran and water, followed by the addition of α,α-dimethoxy-α-phenylacetophenone. The molar ratio of vinyltris(dimethylsiloxane)silane, L-cysteine, tetrahydrofuran, water, and α,α-dimethoxy-α-phenylacetophenone was 0.01 mol: 0.01 mol: 40 mL: 10 mL: 0.1 g. The mixture was stirred for 15 min under 365 nm ultraviolet light irradiation. After stirring, the excess solvent was removed by rotary evaporation, followed by washing with n-hexane to obtain a high-temperature resistant surfactant.

[0057] Example 7

[0058] A method for processing a low-odor antibacterial material includes the following steps:

[0059] Step 1: Add GPPS, the odor adsorbent prepared in Example 1, the antibacterial agent prepared in Example 4, and the compound antioxidant to a high-speed mixer at a mass ratio of 100:1:2:0.1 and premix for 5 minutes at a temperature of 90°C to obtain the premixed material. The compound antioxidant is obtained by compounding antioxidant 168 and antioxidant 1010 at a mass ratio of 1:1. Then, add the premixed material to the hopper and convey it to the twin-screw extruder through the feeding screw.

[0060] Step 2: Mix the high-temperature resistant surfactant obtained in Example 5 with water to obtain a mixture. The mass percentage of the high-temperature resistant surfactant in the mixture is 3%. Then, add 3% of the total mass of the premixed material into a twin-screw extruder through a water inlet. The length-to-diameter ratio of the twin-screw extruder is 56:1. The mixture and the premixed material are kneaded in the twin-screw extruder at a kneading temperature of 170°C for 3 minutes.

[0061] The third step is to evacuate the molten material that reaches the exhaust section, setting the vacuum level to -0.09 MPa, and then extrude and granulate it through the extrusion section to obtain a low-odor antibacterial material.

[0062] Example 8

[0063] A method for processing a low-odor antibacterial material includes the following steps:

[0064] Step 1: Add HIPS, the odor adsorbent prepared in Example 2, the antibacterial agent prepared in Example 4, and the compound antioxidant to a high-speed mixer at a mass ratio of 100:1.5:3:0.2 and premix for 4 minutes at a temperature of 95°C to obtain the premixed material. The compound antioxidant is obtained by compounding antioxidant 168 and antioxidant 1010 at a mass ratio of 1:1. Then, add the premixed material to the hopper and convey it to the twin-screw extruder through the feeding screw.

[0065] Step 2: Mix the high-temperature resistant surfactant obtained in Example 6 with water to obtain a mixture. The mass percentage of the high-temperature resistant surfactant in the mixture is 4%. Then, add 4% of the total mass of the premixed material into a twin-screw extruder through a water inlet. The length-to-diameter ratio of the twin-screw extruder is 56:1. The mixture and the premixed material are kneaded in the twin-screw extruder at a kneading temperature of 180°C for 3 minutes.

[0066] The third step is to evacuate the molten material that reaches the exhaust section, setting the vacuum level to -0.09 MPa, and then extrude and granulate it through the extrusion section to obtain a low-odor antibacterial material.

[0067] Example 9

[0068] A method for processing a low-odor antibacterial material includes the following steps:

[0069] Step 1: Add HIPS, the odor adsorbent prepared in Example 3, the antibacterial agent prepared in Example 4, and the compound antioxidant to a high-speed mixer in a mass ratio of 100:2:3:0.3 and premix for 3 minutes at 100°C to obtain the premixed material. The compound antioxidant is obtained by compounding antioxidant 168 and antioxidant 1010 in a mass ratio of 1:1. Then, add the premixed material to the hopper and convey it to the twin-screw extruder through the feeding screw.

[0070] Step 2: Mix the high-temperature resistant surfactant obtained in Example 6 with water to obtain a mixture. The mass percentage of the high-temperature resistant surfactant in the mixture is 5%. Then, add 5% of the total mass of the premixed material into the twin-screw extruder through the water inlet. The length-to-diameter ratio of the twin-screw extruder is 56:1. The mixture and the premixed material are kneaded in the twin-screw extruder at a kneading temperature of 190°C for 2 minutes.

[0071] The third step is to evacuate the molten material that reaches the exhaust section, setting the vacuum level to -0.09 MPa, and then extrude and granulate it through the extrusion section to obtain a low-odor antibacterial material.

[0072] Comparative Example 3

[0073] Compared with Example 8, this comparative example only replaces "odor adsorbent prepared in Example 2" with "odor adsorbent prepared in Comparative Example 1", while the other raw materials and processing methods are the same as in Example 8.

[0074] Comparative Example 4

[0075] Compared with Example 8, this comparative example only replaces "antibacterial agent prepared in Example 4" with "antibacterial agent prepared in Comparative Example 2". All other raw materials and processing methods are the same as in Example 8.

[0076] Comparative Example 5

[0077] Compared with Example 8, the "high-temperature resistant surfactant prepared in Example 6" was replaced with an equal amount of water, while the other raw materials and processing methods were the same as in Example 8.

[0078] Performance testing:

[0079] The materials obtained in Examples 7-9 and Comparative Examples 3-5 were respectively added into an injection molding machine, and after injection molding, they were made into sheets and their relevant properties were tested.

[0080] Organic compound emissions were measured in accordance with HJ644–2013;

[0081] Antibacterial test: The antibacterial performance value was tested according to the method described in GB / T31402-2015 "Test Method for Antibacterial Properties of Plastic Surfaces", and the antibacterial rate was calculated; Antibacterial rate = (Ct-Tt) / Ct, Ct: mean viable count of control sample over 24 hours (CFU / cm³) 2 Tt: Mean viable bacterial count of the sample over 24 hours (CFU / cm³) 2 The tested bacteria were Escherichia coli and Staphylococcus aureus.

[0082] The test results are shown in Table 1:

[0083] Table 1

[0084]

[0085] As can be seen from the data in Table 1, the low-odor antibacterial material prepared according to the processing method of the present invention has a lower odor and a better antibacterial effect.

[0086] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0087] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for processing a low-odor antimicrobial material, characterized by, It comprises the following steps: The first step is to add polystyrene resin, odor adsorbent, antibacterial agent and compounded antioxidant into a high-speed mixer for premixing to obtain premixed material, then the premixed material is added into a hopper and transported into a double screw extruder through a feeding screw; the polystyrene resin is general polystyrene or impact polystyrene; The second step is to mix high-temperature-resistant surfactant with water to obtain a mixed solution, then the mixed solution is added into the double screw extruder through a water injection port, and the mixed solution is mixed with the premixed material in the double screw extruder; The third step is to vacuumize the molten material reaching the exhaust section, then the material is extruded and granulated in the extrusion section to obtain a low-odor antibacterial material; The odor adsorbent is prepared by the following steps: The porous material is added into an ultrasonic cleaner, then an acid solution is added, ultrasonic oscillation is performed for 5-10 min, then filtration, washing and drying are performed to obtain the odor adsorbent; the porous material is one of zeolite, diatomite and montmorillonite; The antibacterial agent is prepared by the following steps: The tetraphenylbenzyl triethoxysilane is added into an ethanol aqueous solution, the temperature is set to 70℃, ammonia water is added to adjust the pH value to 8, the porous silver-loaded silica is added, stirring is performed for 30 min, ultrasonic dispersion is performed, then filtration, washing, drying, crushing and sieving are performed to obtain the antibacterial agent; The high-temperature-resistant surfactant is prepared by the following steps: Under the protection of nitrogen, the vinyl siloxane and L-cysteine are added into a mixed solution of tetrahydrofuran and water, then a photocatalyst is added, stirring is performed for 10-15 min under 365 nm ultraviolet light irradiation, after the stirring is completed, the excess solvent is removed from the obtained reaction solution by rotary evaporation, then the high-temperature-resistant surfactant is obtained by washing with n-hexane.

2. The method of claim 1, wherein the low-odor antimicrobial material is a polymeric material. The mass ratio of the polystyrene resin, odor adsorbent, antibacterial agent and compounded antioxidant is 100:0.5-2:2-3:0.1-0.

3.

3. The method of claim 1, wherein the low-odor antimicrobial material is a polymeric material. The amount ratio of the tetraphenylbenzyl triethoxysilane, ethanol aqueous solution and porous silver-loaded silica is 2 mL:25 mL:10 g.

4. The method of claim 1, wherein the low-odor antimicrobial material is a polymeric material. The compounded antioxidant is obtained by compounding antioxidant 168 and antioxidant 1010 at a mass ratio of 1:

1.

5. The method of claim 1, wherein the low-odor antimicrobial material is a polymeric material. The amount of the mixed solution in the second step is 2-5% of the total mass of the premixed material; the mass percentage of the high-temperature-resistant surfactant in the mixed solution is 3-5%.

6. The method of claim 1, wherein the low-odor antimicrobial material is a polymeric material. The length-diameter ratio of the double screw extruder is 56:1; the mixing temperature of the double screw extruder is 170-190℃, and the mixing time is not less than 2 min.

7. The method of claim 1, wherein the low-odor antimicrobial material is a polymeric material. The vacuum degree of the vacuumization is -0.09 MPa.

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