Mildew-proof antibacterial door seal material as well as preparation method and application thereof

Abstract

The invention provides a mildew-proof antibacterial door seal material as well as a preparation method and application thereof, and relates to the technical field of door seal materials. The mildewproof antibacterial door seal material is mainly used for refrigerator door seals and is formed by compounding PVC and TPU, and the antibacterial, mildewproof and conductive properties of the material are enhanced by adding graphene aerogel, composite conductive filler and the like. The mildew-proof antibacterial door seal material has good flexibility, cold resistance and durability, can effectively inhibit static electricity accumulation and bacterium breeding, and improves the heat preservation performance and food safety of a refrigerator. Compared with a traditional door seal material, the mildew-proof and antibacterial door seal material is lower in cost and has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of door sealing materials, and in particular to a mildew-proof and antibacterial door sealing material and a preparation method and application thereof. Background Art

[0002] The refrigerator door seal material has an important impact on the refrigerator's sealing, insulation, energy efficiency and service life. After a household refrigerator has been used for a period of time, the surface of the door seal will be contaminated by oil and dust, which will breed harmful microorganisms such as bacteria and mold. In addition, the door seal has many wrinkles and is not easy to clean and replace. Microorganisms contaminate stored food, posing a serious threat to human health. The existing technology usually adds an appropriate amount of antibacterial and mildew-proof agents to the refrigerator door seal material. These antibacterial and mildew-proof agents will slowly migrate from the door seal material to the surface of the material. However, as time goes by, the antibacterial and mildew-proof agents added to the door seal will be consumed, making the door seal have no antibacterial and mildew-proof effect; if excessive antibacterial and mildew-proof agents are added, the organic content in the door seal will increase, increasing safety hazards.

[0003] The refrigerator door seal materials mainly use various thermoplastic elastomers, foam materials and other composite materials to ensure good elasticity and durability at different temperatures to reduce the leakage of cold air. Common refrigerator door seal materials include polyvinyl chloride (PVC), thermoplastic elastomer (TPE), ethylene-vinyl acetate copolymer (EVA), and polyurethane (PU) foam. Among these refrigerator door seal materials, PVC is currently one of the most commonly used materials for refrigerator door seals. It has excellent flexibility, elasticity and anti-aging properties, low cost, and is suitable for long-term sealing. However, PVC may harden at extremely low temperatures, so it is slightly insufficient in cold resistance. TPE material has both the elasticity of rubber and the processing characteristics of plastic, so it is more common in refrigerator door seal materials. TPE has better sealing, wear resistance and environmental protection performance, and can remain soft in low temperature environments, but the cost is higher. EVA material has excellent flexibility, cold resistance and anti-aging properties, and can remain elastic and not crack in low temperature environments. EVA is still more expensive than PVC. PU is basically not used as a refrigerator door seal material, but as a filler to increase the heat insulation and softness of the door seal, making the door seal tighter when it is close to the refrigerator door. At the same time, PU has an excellent insulation effect, which can effectively reduce the temperature difference between the inside and outside of the refrigerator and improve the heat preservation.

[0004] In addition, the existing refrigerator door seal materials have the following problems: (1) The existing refrigerator door seal materials have a narrow antibacterial spectrum and poor antibacterial durability, and cannot effectively inhibit the growth of various molds and harmful bacteria, causing the refrigerator door seals to easily mold and produce odors, affecting food safety. (2) The surface resistance of the existing refrigerator door seal materials is relatively high, which is easy to accumulate static electricity and then absorb dust, affecting the appearance and hygiene. (3) Traditional refrigerator door seal materials use petroleum-based phthalate plasticizers, which are easy to migrate and precipitate, affecting the health of users. (4) The existing PVC substrate performs poorly in terms of flexibility, cold resistance and durability under repeated extrusion, resulting in a short service life of the door seal. (5) The existing materials are insufficient in ice making and low-temperature performance, resulting in increased energy consumption of the refrigerator and may even cause corrosion of the refrigerator liner. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a mildew-proof and antibacterial door seal material and its preparation method and application. The mildew-proof and antibacterial door seal material provided by the present invention is a PVC / TPU composite material. The material uses a composite compatibilizer, a composite conductive filler and a specific preparation process to make the door seal material have good comprehensive performance, which helps to ensure the stability of product performance and service life, and reduce the impact on user health. Compared with door seal materials produced with TPE, EVA and the like as base materials, the price is lower and has good application prospects.

[0006] The present invention provides a mildew-proof and antibacterial door seal material, which is prepared by adding graphene aerogel dispersed by a plasticizer and a polyester thermoplastic elastomer (TPU) and a composite compatibilizer to a PVC composite material. The mildew-proof and antibacterial door seal material is prepared from raw materials including the following components:

[0007] PVC 75-100 parts by mass;

[0008] TPU 10-30 parts by mass;

[0009] 50-70 parts by weight of plasticizer;

[0010] 30 to 50 parts by weight of inorganic filler;

[0011] Antioxidant 0.2-0.5 parts by weight;

[0012] Stabilizer 0.5-1 parts by mass;

[0013] 1 to 3 parts by weight of antifungal and antibacterial agent;

[0014] 1 to 3 parts by weight of composite compatibilizer;

[0015] 20-30 parts by mass of composite conductive filler.

[0016] Preferably, the plasticizer is at least two of epoxidized soybean oil, tributyl citrate, dioctyl adipate, and polyester plasticizer.

[0017] Preferably, the composite compatibilizer is prepared by compounding chlorinated polyethylene and ethylene-vinyl acetate grafted maleic anhydride in a mass ratio of 3:1.

[0018] Preferably, the composite conductive filler is obtained by compounding conductive carbon black, graphene aerogel, and silver-coated glass microbeads in a mass ratio of 10:1:0.5.

[0019] The present invention also provides an application of a mildew-proof and antibacterial door sealing material in a refrigerator door seal, wherein the mildew-proof and antibacterial door sealing material is the mildew-proof and antibacterial door sealing material described in the above technical solution.

[0020] The present invention provides a method for preparing a mildew-proof and antibacterial door sealing material, comprising the following steps:

[0021] S1, pre-dispersing graphene aerogel into a plasticizer to obtain a graphene aerogel slurry;

[0022] S2, adding 2 / 3 of the graphene aerogel slurry obtained in S1 to PVC, heating and stirring, then adding conductive carbon black, silver-plated glass beads, antioxidant, stabilizer, mildew and antibacterial agent, composite compatibilizer, stirring and adding the remaining graphene aerogel slurry;

[0023] S3. After the slurry is added, the inorganic filler calcium carbonate is added at a temperature of 105°C with stirring at a speed of 500r / min, and then the temperature is continued to be stirred and raised to 125°C for pre-plasticization;

[0024] S4. After the pre-molded material is stirred and cooled, TPU elastomer is added, and the mixture is blended under high-speed stirring, and then extruded and granulated to obtain a mildew-proof and antibacterial door sealing material.

[0025] Preferably, the heating stirring rate of S2 is 500 r / min, and the stirring temperature is 90°C.

[0026] Preferably, the temperature of the material after stirring and cooling in S4 is 90°C.

[0027] Preferably, in S4, extrusion is carried out in a twin-screw extruder, and the temperature of the twin-screw extruder zone is: 105℃±5℃ in zone 1, 110℃±5℃ in zone 2, 115℃±5℃ in zone 3, 125℃±5℃ in zone 4, 125℃±5℃ in zone 5, 125℃±5℃ in zone 6, 125℃±5℃ in zone 7, 125℃±5℃ in zone 8, 140℃±5℃ in zone 9, 145℃±5℃ in zone 10, and 150℃±5℃ in zone 11; the head temperature is 150℃±10℃, the feed temperature is 120℃±20℃, the material pressure is ≤13MPa, and the twin screw speed of the twin screw extruder is 18-30Hz.

[0028] Compared with the prior art, the present invention adds composite conductive fillers such as graphene aerogel dispersed by plasticizer, conductive carbon black, and silver-plated glass microspheres to the PVC substrate to make the conductivity of the door seal material reach more than 10S / m and the surface resistivity less than 10 2 Ω, which can effectively inhibit static electricity accumulation, increase the static electricity protection effect of the material, reduce dust accumulation, and play a self-cleaning role. In addition, the composite conductive filler enables the material to have excellent antibacterial and mildew-proof properties, with a wide antibacterial spectrum, high antibacterial rate, and long-lasting antibacterial properties, so that various harmful bacteria, molds, and fungi cannot breed on the refrigerator door seal, thereby improving food safety. The present invention uses the synergistic effect of multiple bio-based plasticizers to replace traditional petroleum-based phthalate small molecule plasticizers, which is green, environmentally friendly, safe and reliable. It not only has good cold resistance and migration resistance, but also improves the ice-making effect of the refrigerator and reduces energy consumption, and reduces the risk of corrosion of the refrigerator liner. The composite conductive filler of the present invention improves the conductivity of the material. The present invention improves the flexibility and toughness of the PVC substrate by adding TPU elastomer and composite compatibilizer, increases the durability of the material in repeated extrusion and door opening and closing operations, and extends the service life of the door seal. The use of the composite compatibilizer of the present invention improves the compatibility between PVC and TPU, effectively improves the mechanical properties, elasticity, cold resistance and other properties of the material, helps to ensure the stability of product performance and service life, and reduces the impact on user health. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings.

[0030] Figure 1 The mildew-proof effect is grade 4 after 180 days of mildew-proof test;

[0031] Figure 2 The mildew-proof effect is Grade 2 after 180 days of mildew-proof test;

[0032] Figure 3 The anti-mildew effect is grade 1 after 180 days of anti-mildew testing. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The present invention provides a mildew-proof and antibacterial door sealing material, which is prepared by adding graphene aerogel dispersed by a plasticizer, TPU, and a composite compatibilizer to a PVC composite material. The mildew-proof and antibacterial door sealing material is prepared from raw materials including the following components:

[0035] PVC 75-100 parts by mass; TPU 10-30 parts by mass; plasticizer 50-70 parts by mass; inorganic filler 30-50; antioxidant 0.2-0.5 parts by mass; stabilizer 0.5-1 parts by mass; mildew and antibacterial agent 1-3 parts by mass; composite volume expander 1-3 parts by mass; composite conductive filler 20-30 parts by mass.

[0036] In the present invention, the graphene aerogel is preferably prepared by a hydrothermal reduction method or a freeze-drying method.

[0037] In the present invention, the plasticizer is at least two of epoxy soybean oil, tributyl citrate, dioctyl adipate and polyester plasticizer.

[0038] In the present invention, the inorganic filler is preferably a calcium carbonate inorganic filler, specifically light calcium carbonate and / or nano calcium carbonate. In some specific embodiments of the present invention, the inorganic filler is light calcium carbonate and nano calcium carbonate. In some preferred embodiments of the present invention, the inorganic filler is compounded by light calcium carbonate and nano calcium carbonate in a mass ratio of 3:1. In the present invention, light calcium carbonate provides basic filling and reinforcing effects, while nano calcium carbonate enhances the antibacterial ability of the material and achieves good comprehensive performance. The appropriate ratio (3:1) of light calcium carbonate and nano calcium carbonate can improve the compatibility of the two fillers in the composite material, thereby improving the overall uniformity and stability. If the proportion of nano calcium carbonate is too high, it will affect the overall uniformity and performance of the material, and if it is too low, the enhancement effect cannot be achieved. And the cost of light calcium carbonate is low, and the use of more light calcium carbonate can effectively control the production cost of the door sealing material and improve the economy.

[0039] In the present invention, the antioxidant is preferably antioxidant 1010 and / or antioxidant 168. Antioxidant 1010 (decylphenol polyoxyethylene ether) and antioxidant 168 (tri(4-tert-butylphenyl) phosphate) have good thermal stability under high temperature conditions, can maintain a stable antioxidant effect during the processing of the composite door sealing material, and ensure the stability of the material in a high temperature environment. Antioxidants 1010 and 168 have good compatibility with the base materials PVC and TPU of the door sealing material of the present invention, can be evenly dispersed in the composite material, and play an antioxidant role without affecting the physical properties of the material. Moreover, the volatility of these two antioxidants is relatively low, and they can maintain antioxidant properties during long-term high-temperature treatment and are not easy to fail, thereby providing continuous antioxidant protection. In the present invention, antioxidants 1010 and 168 can be compounded according to specific needs to provide more powerful antioxidant properties, especially in high temperature and oxidative environments, to delay the aging and degradation of materials. Finally, these two antioxidants have been widely recognized in industrial applications, and their safety is relatively high. They meet modern environmental protection requirements and are suitable for use in products that have certain requirements on the environment and health, such as refrigerators. Therefore, the selection of antioxidant 1010 and / or antioxidant 168 as antioxidants can effectively improve the thermal stability and antioxidant capacity of anti-mildew and antibacterial door seal materials, thereby ensuring the performance of the materials during processing and use, extending their service life, and ensuring product quality.

[0040] In the present invention, the stabilizer is preferably at least one of zinc stearate, calcium stearate, hydrotalcite, pentaerythritol, and phosphite. Zinc stearate and calcium stearate, as metal soap stabilizers, can effectively neutralize the hydrogen chloride produced by the decomposition of the polymer at high temperature, prevent thermal degradation of the material, and provide good thermal stability. And these stabilizers have good compatibility with the base material of the door sealing material, can be evenly dispersed in the material, and improve the physical properties and processing properties of the overall material. Stabilizers such as pentaerythritol and phosphite can provide additional antioxidant protection, help resist aging degradation caused by oxygen and heat in the environment, and improve the durability of the material. Phosphite has low volatility and odor, which can meet the strict requirements of household appliances and sealing materials for odor and safety. Hydrotalcite, as a layered material, in addition to providing thermal stability, can also adsorb and neutralize acidic substances produced during the degradation of the material, providing a longer-lasting stabilizing effect. The present invention selects zinc stearate, calcium stearate, hydrotalcite, pentaerythritol, phosphite and the like as stabilizers, which can effectively improve the thermal stability, durability and safety of the mildew-proof and antibacterial door sealing material, and ensure the excellent performance of the material during processing and use.

[0041] In the present invention, the mildew and antibacterial agent is preferably at least two of 4,5-dichloro-N-octyl-4-isothiazoline-3-one, zinc pyrithione, and 2-butyl-1,2-benzisothiazolin-3-one. The mildew and antibacterial agent of the present invention has a broad-spectrum antibacterial and mildew-proof effect, and can effectively inhibit the growth of various bacteria and fungi, especially in a humid environment, to ensure the long-term hygiene of the material. The use of a composite mildew and antibacterial agent can produce a synergistic effect, and the selection of a variety of antibacterial agents can be adjusted according to actual needs to ensure effective resistance to possible microbial threats under different use environments and enhance the overall antibacterial effect. These mildew and antibacterial agents have good chemical stability under different environmental conditions, are not easily degraded, can maintain their effectiveness during the use of the material, can provide long-term antibacterial protection under the premise of a lower dosage, and the mildew and antibacterial agent of the present invention usually shows relatively low toxicity in application, which meets people's requirements for environmental protection and health. Therefore, the present invention preferably uses 4,5-dichloro-N-octyl-4-isothiazoline-3-one, zinc pyrithione, 2-butyl-1,2-benzisothiazolin-3-one, etc. as mildew and antibacterial agents to give full play to their superior antibacterial properties and ensure the effectiveness and durability of mildew and antibacterial door sealing materials in humid and polluted environments.

[0042] The antibacterial properties of the mildew-proof and antibacterial door seal material provided by the present invention improve the hygienic performance of the seal, making it suitable for use in highly clean, humid and temperature-fluctuating environments. Therefore, in addition to being used in refrigerators, the mildew-proof and antibacterial door seal material of the present invention is also widely used in fields with high requirements for cleanliness and antibacterial to prevent the growth of mold and bacteria and ensure the hygiene of the use environment. These materials are commonly found in the following fields: Home appliance field: used in door seals of home appliances such as washing machines to prevent the growth of bacteria and mold in humid environments and keep food and clothing clean; Medical and health field: used in hospital door and window seals and clean room sealing systems to avoid cross-infection of pathogens and maintain the sterile state of the environment; Food processing and cold chain transportation: cold storage door seals, refrigerated truck door seals, etc., to ensure effective inhibition of microbial reproduction in low temperature and humid environments, and to ensure food safety and hygiene; Construction field: used in door seal materials in humid areas such as kitchens and bathrooms to reduce mold production and keep indoor air fresh; Laboratories and pharmaceutical industries: used in door seals of clean rooms and laboratories to prevent microbial contamination and cross-infection and ensure the purity of drugs and experiments. The antibacterial properties of the anti-mildew and antibacterial door seal material improve the hygienic performance of the seal, making it suitable for use in highly clean, humid and temperature-fluctuating environments.

[0043] In some specific embodiments of the present invention, the mildew-proof and antibacterial door sealing material also includes a suitable amount of color powder.

[0044] The present invention also provides a method for preparing the mildew-proof and antibacterial door sealing material described in the above technical solution, comprising the following steps:

[0045] S1, pre-dispersing graphene aerogel into a plasticizer to obtain a graphene aerogel slurry;

[0046] S2, adding 2 / 3 of the graphene aerogel slurry obtained in S1 to PVC, heating and stirring, then adding conductive carbon black, silver-plated glass beads, antioxidant, stabilizer, mildew and antibacterial agent, composite compatibilizer, stirring and adding the remaining graphene aerogel slurry;

[0047] S3. After the slurry is added, the inorganic filler calcium carbonate is added at a temperature of 105°C with stirring at a speed of 500r / min, and then the temperature is continued to be stirred and raised to 125°C for pre-plasticization;

[0048] S4. After the pre-molded material is stirred and cooled, TPU elastomer is added, and the mixture is blended under high-speed stirring, and then extruded and granulated to obtain a mildew-proof and antibacterial door sealing material.

[0049] In the present invention, the heating stirring rate of S2 is preferably 500 r / min, and the stirring temperature is 90°C.

[0050] In the present invention, the pre-plasticization temperature of S2 is preferably 110°C.

[0051] In the present invention, the extrusion is carried out in a twin-screw extruder. In the S4, the parameters of the twin-screw extruder are preferably set as follows: the zone temperatures are set to: 105°C±5°C for zone one, 110°C±5°C for zone two, 115°C±5°C for zone three, 125°C±5°C for zone four, 125°C±5°C for zone five, 125°C±5°C for zone six, 125°C±5°C for zone seven, 125°C±5°C for zone eight, 140°C±5°C for zone nine, 145°C±5°C for zone ten, and 150°C±5°C for zone eleven; the head temperature is 150°C±10°C, the feed temperature is 120°C±20°C, the material pressure is ≤13MPa, and the twin screw speed of the twin-screw extruder is 18-30Hz.

[0052] The present invention forms a graphene aerogel slurry by pre-dispersing graphene aerogel into a liquid plasticizer, and promotes it to cooperate with other conductive fillers to form a conductive path and network. The graphene aerogel slurry has a rich pore structure, ultra-low density and good conductivity, which is convenient for the diffusion and transmission of polymer fluids in its three-dimensional network structure. The three conductive fillers work synergistically and play a good conductive role under a specific ratio. At the same time, the present invention also strictly controls the addition time and the addition amount of the graphene aerogel each time to better control the dispersion degree of the graphene aerogel and avoid agglomeration, thereby improving the uniformity and dispersibility of graphene, ensuring that its performance in the composite material is maximized, and improving the mechanical properties and functionality of the composite material.

[0053] To further illustrate the present invention, the following examples are used for detailed description. The conductive carbon black used in the following examples of the present invention was purchased from Shenzhen Jitian Chemical Co., Ltd.; the graphene aerogel was purchased from Anhui Keang Nano Technology Co., Ltd.; the silver-coated glass microspheres were purchased from Beijing Antepna Science and Trade Co., Ltd., and the remaining raw materials were commercially available.

[0054] Unless otherwise specified, all experiments were repeated three times. SPSS 21.0 was used for analysis of variance (ANOVA) and Duncan's multiple comparison analysis. The results were expressed as mean ± standard deviation, and P < 0.05 indicated a significant difference.

[0055] Embodiment 1 A mildew-proof and antibacterial door sealing material is prepared from the following raw materials:

[0056] 90 parts by mass of PVC; 20 parts by mass of TPU; 65 parts by mass of plasticizer; 45 parts by mass of inorganic filler; 0.5 parts by mass of antioxidant; 0.8 parts by mass of stabilizer; 1.5 parts by mass of antifungal and antibacterial agent; 2 parts by mass of composite compatibilizer; 30 parts by mass of composite conductive filler.

[0057] The plasticizer is composed of tributyl citrate and dioctyl adipate in a mass ratio of 1:1; the composite compatibilizer is obtained by compounding chlorinated polyethylene and ethylene-vinyl acetate grafted maleic anhydride in a mass ratio of 3:1; the composite conductive filler is obtained by compounding conductive carbon black, graphene aerogel and silver-plated glass microbeads in a mass ratio of 10:1:0.5; the inorganic filler is compounded by light calcium carbonate and nano calcium carbonate in a mass ratio of 3:1; the antioxidant is antioxidant 168; the stabilizer is composed of zinc stearate and calcium stearate in a mass ratio of 1:1; the mildew and antibacterial agent is composed of 4,5-dichloro-N-octyl-4-isothiazoline-3-one and zinc pyrithione in a mass ratio of 2:3.

[0058] This embodiment also provides a method for preparing a mildew-proof and antibacterial door seal material, the steps of which are as follows:

[0059] S1, pre-dispersing graphene aerogel into a plasticizer to obtain a graphene aerogel slurry;

[0060] S2, adding 2 / 3 of the graphene aerogel slurry obtained in S1 to PVC, stirring at 500 r / min until the temperature reaches 90°C, then adding conductive carbon black, silver-plated glass beads, antioxidant, stabilizer, mildew and antibacterial agent, composite compatibilizer, and stirring and adding the remaining graphene aerogel slurry at 500 r / min;

[0061] S3. After the slurry is added, the inorganic filler calcium carbonate is added at a temperature of 105°C with stirring at a speed of 500r / min, and then the temperature is continued to be stirred and raised to 125°C for pre-plasticization;

[0062] S4. After the pre-plasticized material is stirred and cooled to 90°C, TPU elastomer is added, and the mixture is blended at a stirring speed of 500 r / min for 10 minutes, and then extruded and granulated. The granular material is sieved through two layers of 150 mesh to obtain a mildew-proof and antibacterial door sealing material.

[0063] In S4, extrusion is carried out in a twin-screw extruder, and the temperatures of the zones of the twin-screw extruder are: 105°C in zone 1, 110°C in zone 2, 115°C in zone 3, 125°C in zone 4, 125°C in zone 5, 125°C in zone 6, 125°C in zone 7, 125°C in zone 8, 140°C in zone 9, 145°C in zone 10, and 150°C in zone 11; the die temperature is 150°C, the feed temperature is 120°C, the material pressure is ≤13MPa, and the twin screw speed of the twin-screw extruder is 25Hz.

[0064] Comparative Example 1

[0065] Same as Example 1, except that no TPU and no composite compatibilizer are used.

[0066] Comparative Example 2

[0067] Same as Example 1, except that no composite compatibilizer was used.

[0068] Comparative Example 3

[0069] Same as Example 1, except that no composite compatibilizer is used, and the composite compatibilizer is replaced by an equal amount of chlorinated polyethylene.

[0070] Comparative Example 4

[0071] Same as Example 1, except that: no composite compatibilizer is used, and the composite compatibilizer is replaced by an equal amount of ethylene-vinyl acetate grafted maleic anhydride.

[0072] Comparative Example 5

[0073] Same as Example 1, except that: the composite compatibilizer is prepared by compounding chlorinated polyethylene and ethylene-vinyl acetate grafted maleic anhydride in a mass ratio of 1:3;

[0074] Comparative Example 6

[0075] Same as Example 1, except that: no composite conductive filler is used, and the composite conductive filler is replaced by an equal amount of conductive carbon black.

[0076] Comparative Example 7

[0077] The same as Example 1, except that: the composite conductive filler is obtained by compounding conductive carbon black, graphene aerogel, and silver-coated glass microbeads in a mass ratio of 5:1:1.

[0078] Comparative Example 8

[0079] The same as Example 1, except that the graphene aerogel is not pre-dispersed in the plasticizer to obtain the graphene aerogel slurry, the specific steps are as follows:

[0080] S1. Stir graphene aerogel, plasticizer, conductive carbon black, silver-coated glass microbeads, antioxidant, stabilizer, mildew and antibacterial agent, and composite compatibilizer at 500 r / min, and then heat to 110° C.;

[0081] S2. Heat to 105°C with stirring at 500 r / min, add inorganic filler calcium carbonate, and stir at 500 r / min until the temperature reaches 125°C;

[0082] S3. After the pre-plasticized material is stirred and cooled to 90°C, TPU elastomer is added, and the mixture is blended under high-speed stirring for 10 minutes, and then extruded and granulated. The granular material is passed through two layers of 150-mesh sieves to obtain a mildew-proof and antibacterial door sealing material.

[0083] In S4, the extrusion is carried out in a twin-screw extruder, and the parameter setting of the twin-screw extruder is the same as that of Example 1.

[0084] The door seal materials obtained in Example 1 and Comparative Examples 1-8 were subjected to performance tests. The mildew resistance test standard is Appendix C of "Special Requirements for Antibacterial, Sterilization and Purification Antibacterial Materials for Household and Similar Electrical Appliances". The sample test results are shown in Table 1.

[0085] Table 1 Performance test results

[0086]

[0087]

[0088] The product of Comparative Example 2 was delaminated and fractured, and did not meet the basic quality requirements of the product, so the product performance was not tested.

[0089] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A mildew-proof and antibacterial door sealing material, characterized in that: The anti-mildew and antibacterial door sealing material is prepared by adding graphene aerogel dispersed by a plasticizer, polyester thermoplastic elastomer, and a composite compatibilizer to a PVC composite material. The anti-mildew and antibacterial door sealing material is prepared from raw materials including the following components: PVC 75-100 parts by mass; TPU 10-30 parts by mass; 50-70 parts by weight of plasticizer; 30 to 50 parts by weight of inorganic filler; Antioxidant 0.2-0.5 parts by weight; Stabilizer 0.5-1 parts by mass; 1 to 3 parts by weight of antifungal and antibacterial agent; 1 to 3 parts by weight of composite compatibilizer; 20-30 parts by mass of composite conductive filler; The composite compatibilizer is prepared by compounding chlorinated polyethylene and ethylene-vinyl acetate grafted maleic anhydride; The composite conductive filler is obtained by compounding conductive carbon black, graphene aerogel and silver-plated glass microbeads in a mass ratio of 10:1:0.

5.

2. The mildew-proof and antibacterial door sealing material according to claim 1, characterized in that: The plasticizer is at least two of epoxy soybean oil, tributyl citrate, dioctyl adipate and polyester plasticizer.

3. The mildew-proof and antibacterial door sealing material according to claim 1, characterized in that: The antioxidant is 1010 and / or antioxidant 168.

4. The mildew-proof and antibacterial door sealing material according to claim 1, characterized in that: The stabilizer is at least one of zinc stearate, calcium stearate, hydrotalcite, pentaerythritol and phosphite.

5. The mildew-proof and antibacterial door sealing material according to claim 1, characterized in that: The mildew and antibacterial agent is at least two of 4,5-dichloro-N-octyl-4-isothiazoline-3-one, zinc pyrithione, and 2-butyl-1,2-benzisothiazolin-3-one.

6. A method for preparing the mildew-proof and antibacterial door sealing material according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, pre-dispersing graphene aerogel into a plasticizer to obtain a graphene aerogel slurry; S2, adding 2 / 3 of the graphene aerogel slurry obtained in S1 to PVC, heating and stirring, then adding conductive carbon black, silver-plated glass beads, antioxidant, stabilizer, mildew and antibacterial agent, composite compatibilizer, stirring and adding the remaining graphene aerogel slurry; S3. After the slurry is added, the inorganic filler calcium carbonate is added at a temperature of 105°C with stirring at a speed of 500r / min, and then the temperature is continued to be stirred and raised to 125°C for pre-plasticization; S4. After the pre-molded material is stirred and cooled, TPU elastomer is added, and the mixture is blended under high-speed stirring, and then extruded and granulated to obtain a mildew-proof and antibacterial door sealing material.

7. The preparation method according to claim 5, characterized in that: The heating stirring rate of S2 is 500r / min, and the stirring temperature is 90°C.

8. The preparation method according to claim 5, characterized in that: In the S4, extrusion is carried out in a twin-screw extruder, and the temperatures of the zones of the twin-screw extruder are: 105°C±5°C in zone 1, 110°C±5°C in zone 2, 115°C±5°C in zone 3, 125°C±5°C in zone 4, 125°C±5°C in zone 5, 125°C±5°C in zone 6, 125°C±5°C in zone 7, 125°C±5°C in zone 8, 140°C±5°C in zone 9, 145°C±5°C in zone 10, and 150°C±5°C in zone 11; the head temperature is 150°C±10°C, the feed temperature is 120°C±20°C, the material pressure is ≤13MPa, and the twin screw speed of the twin-screw extruder is 18-30Hz.

9. Application of a mildew-proof and antibacterial door seal material in a refrigerator door seal, characterized in that: The mildew-proof and antibacterial door sealing material is the mildew-proof and antibacterial door sealing material according to any one of claims 1 to 5 or the mildew-proof and antibacterial door sealing material prepared by the preparation method according to any one of claims 6 to 9.

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