Hydrophobic master batch, preparation method and application

Abstract

The invention relates to the field of material science, in particular to a hydrophobic master batch, a preparation method and application. The invention further discloses a specific two-step process for preparing the hydrophobing agent master batch and then preparing the fluoride-free hydrophobic modified plastic with the antibacterial effect. The specific process effectively avoids adverse effects caused by direct mixing of a hydrophobic agent and an antibacterial agent, the surface contact angle of the fluoride-free hydrophobic modified plastic using the hydrophobic master batch and having the antibacterial effect can reach 113-115 degrees, and the contact angle can still be kept at 109-113 degrees even after the plastic is boiled in water at 70 DEG C for 1000 hours; and after the product is boiled in water at 100 DEG C for 168 hours, the contact angle is also maintained at 106-110 degrees, so that the product is obviously superior to a traditional processing mode of directly adding a water repellent agent, and shows more efficient and long-acting stain resistance.

Description

Technical Field

[0001] The present invention relates to the field of materials science, and particularly to a hydrophobic masterbatch, a preparation method and an application thereof. Background Art

[0002] The surface properties of materials have an important impact on their application performance, and hydrophobicity is a key index determining the stain resistance of materials. Usually, the contact angle is used as a measurement standard. Materials with a contact angle greater than 90° have a hydrophobic surface, which is conducive to the sliding of water droplets; while materials with a contact angle less than 90° are hydrophilic and prone to water stain and dirt residue. At present, the contact angle of ordinary modified polypropylene (PP) materials is about 85°, belonging to hydrophilic materials. When used in closed environments such as washing equipment, bacteria, microorganisms are likely to grow and mildew spots are likely to occur, making it difficult to meet the stain resistance requirements.

[0003] At present, fluorine-containing polymer materials are a widely used type of hydrophobic materials. Such materials have a unique molecular structure, where fluorine atoms are spirally distributed along the carbon chain, forming a strong shielding effect, making the material surface exhibit extremely low surface energy and chemical inertness, thus possessing excellent hydrophobicity. The water contact angle of fluorine-containing polymer materials can reach a relatively high level, with a contact angle of 110° - 120° achievable, and they have been applied in many fields with strict requirements for hydrophobicity. However, with the continuous improvement of environmental awareness, the environmental problems of fluorine-containing hydrophobic materials have gradually emerged. When fluorine-containing hydrophobic materials are applied in daily life, due to their extremely high chemical stability, fluorides on the material surface may gradually be released during long-term use. Once these fluorides enter the natural environment, it is extremely difficult for them to be decomposed through the natural degradation process, and they will accumulate in environmental media such as soil and water bodies, posing a potential hazard to the ecosystem. Research shows that the long-term accumulation of fluorides may affect the growth and development of plants, change the physical and chemical properties of the soil, have a negative impact on the survival and reproduction of aquatic organisms, and thus disrupt the entire ecological balance. In addition to environmental problems, the cost of fluorine-containing hydrophobic materials is also an issue that cannot be ignored. The production process of fluorine-containing polymer materials is complex and requires special raw materials and equipment, resulting in their high price. In actual applications, in order to achieve good stain resistance effects, a large amount of fluorine-containing hydrophobic materials are often needed, which further increases the production cost. For some industries that are sensitive to costs, such as packaging and daily necessities, the excessively high cost limits the wide application of fluorine-containing hydrophobic materials, which does not meet the development needs of the current environment of cost reduction and efficiency improvement.

[0004] CN117209893B discloses a hydrophobic modified polypropylene plastic and its preparation method. This technology melts and blends polypropylene, polytetrafluoroethylene, fluorinated modified polypropylene and a compatibilizer, and adopts rapid cooling and plasma discharge treatment, which improves the hydrophobicity and mechanical properties of the material to a certain extent. By optimizing the blending process, the contact angle of the material is effectively increased, showing a significant improvement compared with conventional polypropylene; the plasma discharge treatment is adopted to improve the fluorination modification efficiency; adding a small amount of nitric oxide in the reaction atmosphere inhibits the destruction of molecular chains and ensures the performance stability of the material. However, this technology has many deficiencies. First, the raw materials contain fluorine-containing substances such as polytetrafluoroethylene and fluorinated modified polypropylene, which makes the material have a risk of fluoride release during use and pose a potential hazard to the environment. At the same time, due to the difficult degradability of fluorine-based materials, the discarded materials will exist in the natural environment for a long time, exacerbating the environmental burden. Second, although this technology improves the hydrophobicity of the material to a certain extent, in a closed and humid environment, such as the inside of a washing device, its stain resistance still needs to be further improved. In this environment, the breeding conditions of bacteria and microorganisms are still relatively favorable, and the material surface is easily contaminated, making it difficult to meet the sanitary requirements of actual applications. In addition, this technology lacks antibacterial function and cannot effectively inhibit the growth of bacteria and microorganisms, and cannot fully meet the needs of application scenarios with high sanitary requirements such as washing devices.

[0005] Ju in "Preparation and Hydrophobic Property Research of Superhydrophobic Membranes of PP and Polystyrene (PS)" (Heilongjiang Science, 2023, 14 (14): 72-79) prepared thin films by the solution method and optimized process parameters such as solvent selection, solution concentration and drying conditions, and successfully prepared superhydrophobic materials with contact angles reaching 154° (PP film) and 152° (PS film) respectively. This research reveals the important influence of the microscopic rough structure on the superhydrophobic property, providing a theoretical basis for the preparation of superhydrophobic materials; establishing a process parameter system for preparing superhydrophobic membranes by the solution method, showing certain technological innovation. However, this research has obvious limitations. On the one hand, only the contact angle of ultrapure water was tested. In actual applications, the materials face a complex sewage environment, which contains various impurities, microorganisms and chemical substances, and their effects on the material surface are very different from those of ultrapure water. Therefore, based only on the test results of the contact angle of ultrapure water, the performance of the material in the actual sewage environment cannot be accurately evaluated, limiting the popularization of this technology in actual applications; on the other hand, this research lacks the study of antibacterial properties. In many actual application scenarios, such as food packaging, medical and health fields, the materials not only need to have good hydrophobicity, but also need to have antibacterial function to prevent bacteria from breeding and ensure the safety and sanitation of products.

[0006] Currently, there are mainly two technical bottlenecks in the preparation process of hydrophobic agents, namely the processing stability of hydrophobic agents and the problem of synergistic effect with antibacterial agents. Commonly used hydrophobic agents mainly include fluorine-based polymer materials, silane compounds, and some nano-scale hydrophobic fillers. During the processing of hydrophobic materials, the stability of these hydrophobic agents when added to the extruder is poor, which has an adverse impact on the performance of the materials. Fluorine-based hydrophobic agents represented by polytetrafluoroethylene have extremely high chemical inertness and thermal stability, and their melt viscosity is extremely high. When mixed with other materials (such as polypropylene), due to the obvious viscosity difference between the two, it is difficult for fluorine-based hydrophobic agents to be evenly dispersed in the matrix material. During the extrusion processing stage, this uneven dispersion problem will cause local enrichment of fluorine-based hydrophobic agents in the material, resulting in inconsistent properties of each part of the material and affecting the stability of the material properties. For example, in the production of plastic products, locally enriched fluorine-based hydrophobic agents may cause defects on the surface of the products, such as unevenness and uneven color, reducing the quality and appearance of the products; Silane-based hydrophobic agents generally exist in the form of small molecules and have strong volatility. During the high-temperature extrusion process, silane compounds are prone to volatilization or decomposition, resulting in the loss of active ingredients and making it difficult to form a stable hydrophobic structure on the material surface, thus making it difficult to ensure a stable hydrophobic effect. In addition, the volatilization of silane-based hydrophobic agents may also cause pollution to the production environment and affect the health of operators; Nano-scale hydrophobic fillers (such as hydrophobic silica), due to their large specific surface area and surface energy, are prone to agglomeration. During the extrusion processing process, once the nano-particles agglomerate, they cannot be evenly dispersed in the material, which will not only affect the hydrophobic performance of the material, but also have an adverse impact on its mechanical properties. The agglomerated nano-particles will form stress concentration points inside the material, reducing the strength and toughness of the material and making the material prone to cracking and deformation during use.

[0007] In practical applications, many scenarios require materials to have both good hydrophobicity and antibacterial function. However, improper addition of hydrophobic agents and antibacterial agents will have adverse effects on the antibacterial effect of the material, which is mainly reflected in the following aspects: First, there is a competitive effect between hydrophobic agents and antibacterial agents in the material. Taking hydrophobic agents such as fluorine polymers and silane compounds as an example, they will occupy the active sites on the surface of the material, making it impossible for the antibacterial agent to be effectively distributed on the surface of the material. For example, fluorine polymer hydrophobic agents will form a dense low surface energy layer on the surface of the material, hindering the contact between the antibacterial agent and bacteria, thereby reducing the antibacterial effect; secondly, there are compatibility issues between hydrophobic agents and antibacterial agents. Some hydrophobic agents with strong chemical inertness (such as fluorine polymers) may hinder the release of antibacterial agents such as silver ions and quaternary ammonium salt antibacterial agents, weakening the activity of antibacterial agents. Silver ion antimicrobial agents need to release silver ions to destroy the cell membrane and DNA of bacteria in order to achieve the purpose of antibacterial effect. However, when fluorine-based polymer hydrophobic agents are present, they may interact with silver ions, making it difficult for silver ions to be released, ultimately resulting in a decrease in the antibacterial effect. Furthermore, the addition of hydrophobic agents will change the surface properties of the material, such as surface charge, roughness, etc. These changes may affect the way the antimicrobial agent interacts with bacteria and reduce the antibacterial effect. For example, the addition of hydrophobic agents may make the surface of the material smoother and reduce the attachment sites of bacteria, but at the same time it may also reduce the probability of contact between the antimicrobial agent and bacteria, affecting the antibacterial effect. Finally, during the high-temperature extrusion process, the hydrophobic agent and the antimicrobial agent may undergo thermal degradation or interaction, resulting in a decrease in the activity of both, affecting the antibacterial effect. Some antimicrobial agents are easily decomposed at high temperatures and lose their antibacterial activity, while the interaction between the hydrophobic agent and the antimicrobial agent may change their chemical structure, causing them to lose their original function.

[0008] In summary, although the existing technology has achieved certain results in the hydrophobicity of materials, there are still many problems that need to be solved. In terms of environmental friendliness, some technologies use fluorine-containing raw materials, which have environmental risks of fluoride release and difficult degradation, and do not meet the requirements of sustainable development; in terms of antibacterial performance, the antibacterial effect of existing technologies needs to be further improved, and it is difficult to meet the increasingly stringent hygiene requirements, especially in some fields with extremely high requirements for hygiene standards, such as medical care, food processing, etc. In terms of stain resistance in actual application environments, existing materials cannot effectively resist stains and bacterial invasion in complex actual environments, such as the humid and multi-bacteria environment inside washing equipment, and need further improvement. Summary of the invention

[0009] In order to solve the problems existing in the prior art, the present invention provides a fluorine-free hydrophobic modified plastic with antibacterial effect that has long-lasting stain resistance, antibacterial function and environmental friendliness. The fluorine-free hydrophobic modified plastic with antibacterial effect is prepared by a unique two-step method. The first step is to prepare a hydrophobic agent masterbatch, and the second step is to prepare the fluorine-free hydrophobic modified plastic with antibacterial effect. The two-step method avoids the adverse effects of direct mixing of the hydrophobic agent and the antibacterial agent by first preparing the hydrophobic masterbatch and then mixing it with the antibacterial agent, thereby improving the stability and repeatability of the process. The unique two-step preparation process of the present invention not only improves the stain resistance of the material, but also makes the production process more controllable and significantly improves the efficiency by first preparing the hydrophobic masterbatch and then producing the stain-resistant material. The specific technical scheme is as follows: A hydrophobic masterbatch comprises 20-90 parts of a synthetic resin, 5-40 parts of a hydrophobic agent, and 5-40 parts of an adsorbent.

[0010] Furthermore, the synthetic resin is one or a mixture of two or more of homopolypropylene resin, block copolymer polypropylene resin, random copolymer polypropylene resin, polyethylene, polyvinyl chloride, polystyrene, ABS resin, and polycarbonate; the synthetic resin serves as a matrix material and provides mechanical strength and processing performance.

[0011] Furthermore, the average molecular weight of the polypropylene resin is 200,000-600,000. Due to its moderate molecular weight, it ensures good melt fluidity and at the same time guarantees the mechanical properties of the final product.

[0012] Furthermore, the hydrophobic agent is any one of an organosilicon hydrophobic agent, an organofluorine hydrophobic agent, a hydrocarbon hydrophobic agent, and a wax hydrophobic agent, or a mixture of two or more thereof; the organosilicon hydrophobic agent, by virtue of its unique chemical structure, can form a low surface energy layer on the surface of the material through the dual effects of chemical bonding and physical adsorption, significantly reduce the surface energy of the material, and increase the contact angle to 113°-115°. For example, aminosilicone is a type of organosilicon hydrophobic agent, and the amino group (-NH2) and siloxane chain segment in its molecule act on the surface of the material. On the one hand, the amino group can form chemical bonds with certain groups on the surface of the material to enhance the bonding force between the hydrophobic agent and the material; on the other hand, the siloxane chain segment has an extremely low surface energy, which effectively reduces the interfacial tension between the surface of the material and water, thereby achieving excellent hydrophobic properties.

[0013] Furthermore, the silicone water repellent is selected from any one or a mixture of two or more of amino silicone, polysiloxane, long-chain alkyl silane, amino silane, epoxy silane, mercapto silane, and modified polysiloxane; different types of silicone water repellents exhibit different characteristics when acting on the material surface due to the differences in their functional groups. The amino group in amino silicone has strong reactivity and can undergo chemical reactions with groups on the surfaces of various materials, enhancing the adhesion effect of the water repellent; polysiloxane has good chemical stability and low surface energy characteristics, which can effectively improve the hydrophobic persistence of the material; the long-chain structure of long-chain alkyl silane can further reduce the surface energy of the material and enhance the hydrophobic performance; by selecting different types of silicone water repellents for compounding, the hydrophobic performance of the material can be customized according to actual needs.

[0014] Furthermore, the adsorbent is selected from any one or a mixture of two or more of supercritical foamed polypropylene, activated carbon, silica gel, and polyacrylamide.

[0015] The present invention also provides a method for preparing the hydrophobic masterbatch, and the specific method is as follows: Step 1: Add 5 - 40 parts of the water repellent and 5 - 40 parts of the adsorbent to a low-speed mixer and stir for 2 - 10 min at a stirring rate of 100 - 200 r / min to obtain the water repellent after adsorption. Then, add the water repellent after adsorption and 20 - 90 parts of the synthetic resin to a high-speed mixer and stir for 2 - 5 min at a stirring rate of 150 - 300 r / min to obtain the masterbatch; in the low-speed mixing stage, a lower stirring rate can enable the water repellent and the adsorbent to fully contact in a relatively gentle environment, which is conducive to the effective adsorption of the water repellent molecules on the surface of the adsorbent, avoiding the situation that the adsorption sites on the surface of the adsorbent are not fully utilized due to too fast stirring or the water repellent is overly dispersed and unable to effectively combine with the adsorbent; when the water repellent after adsorption is mixed with the synthetic resin in the high-speed mixer, a higher stirring rate can prompt the water repellent after adsorption to quickly disperse in the synthetic resin, and the shear force generated by high-speed stirring can break the aggregates that the water repellent after adsorption may form, enabling it to be evenly distributed in the synthetic resin with a smaller particle size, laying a foundation for forming a uniform and stable system in subsequent extrusion granulation; compared with the traditional one-step mixing process, the step-by-step mixing method of the present invention can effectively improve the mixing uniformity of each component and reduce the product performance differences caused by uneven mixing; Step 2: Add the masterbatch to a twin-screw extruder for extrusion granulation to obtain the hydrophobic masterbatch.

[0016] Furthermore, set the processing temperature of the conveying section of the twin-screw extruder to 160 - 170 °C, the processing temperature of the compression section to 180 - 190 °C, the processing temperature of the homogenization section to 170 - 180 °C, the screw rotation speed to 400 - 600 r / min, the feeding rate to 40 - 80 kg / h, and the length-diameter ratio of the twin-screw extruder to 44 - 60:1; in the conveying section, controlling the temperature at 160 - 170 °C can ensure that the material has a certain fluidity while avoiding the decomposition or volatilization of the heat-sensitive components in the hydrophobic agent due to excessive temperature. If the temperature exceeds the appropriate range, the loss of the active ingredients of the hydrophobic agent will reduce the hydrophobic performance of the material; when the temperature in the compression section rises to 180 - 190 °C, the material is compressed under the push of the screw at this time, and the combined action of temperature and pressure promotes further melting of the material, enhances the intermolecular interaction, and improves the uniformity of the material; the temperature maintained in the homogenization section is 170 - 180 °C, which can ensure that the temperature and composition of the material are uniform before extrusion, and avoid quality problems in the extruded product due to local temperature or composition differences; the appropriate screw rotation speed, feeding rate, and length-diameter ratio cooperate with each other to ensure that the material has sufficient residence time in the extruder, achieving sufficient melting, mixing, and plasticization; the screw rotation speed determines the conveying speed of the material in the extruder and the magnitude of the shear force received, and the feeding rate needs to match the screw rotation speed to maintain the stability of the extrusion process; the twin-screw extruder with a larger length-diameter ratio provides a longer reaction and mixing space, which is beneficial to the homogenization of the material; compared with the existing extrusion process, the present invention significantly improves the quality and production efficiency of the hydrophobic masterbatch by precisely controlling the temperature of each section of the extruder, the screw rotation speed, the feeding rate, and the length-diameter ratio, avoids the factors that the stability of the hydrophobic agent is poor when added to the extruder, which has an adverse impact on the performance of the material, and reduces the defective rate.

[0017] The present invention also provides a fluorine-free hydrophobic modified plastic with antibacterial effect, and the fluorine-free hydrophobic modified plastic with antibacterial effect uses the aforementioned hydrophobic masterbatch; by using the above-mentioned hydrophobic masterbatch, the synergistic effect of each component in the hydrophobic masterbatch can be utilized to endow the modified plastic with excellent hydrophobic performance; at the same time, it creates good matrix conditions for subsequent addition of antibacterial agents and other additives to prepare materials with both hydrophobic and antibacterial properties, and avoids the problem that the hydrophobic performance drops significantly after adding components such as antibacterial agents due to the poor hydrophobic performance of the matrix material; compared with the hydrophobic antibacterial plastics prepared with ordinary materials as the matrix in the prior art, the present invention is based on the hydrophobic masterbatch and can better balance the relationship between hydrophobic performance and other properties.

[0018] The present invention also provides a method for preparing the fluorine-free hydrophobic modified plastic with antibacterial effect, which is characterized in that: 10 parts of the aforementioned hydrophobic masterbatch, 40 - 95 parts of polypropylene resin, 0.1 - 3 parts of antibacterial agent, 0.1 - 1 part of antioxidant, and 0.1 - 2 parts of lubricant are added to a high-speed mixer and mixed for 3 - 5 min to obtain a mixture, with a stirring rate of 150 - 300 r / min. Then, the mixture is added to a twin-screw extruder from the main feeding port. The length-diameter ratio of the twin-screw extruder is 44 - 60:1. The processing temperature of the conveying section is set at 180 - 190 °C, the processing temperature of the compression section is 200 - 210 °C, the processing temperature of the homogenization section is 180 - 190 °C, the screw speed is 300 - 500 r / min, and the feeding rate is 50 kg / h, to obtain the fluorine-free hydrophobic modified plastic with antibacterial effect.

[0019] In the mixing stage in the high-speed mixer, through stirring for 3 - 5 min at 150 - 300 r / min, the hydrophobic masterbatch, polypropylene resin, antibacterial agent, antioxidant, and lubricant are fully contacted and preliminarily mixed. Under the action of the stirring force, each component is dispersed in each other, preparing for the further reaction and uniform mixing in the twin-screw extruder. In the twin-screw extruder, the temperature of the conveying section is set at 180 - 190 °C to rapidly melt the material. After entering the compression section, the high temperature of 200 - 210 °C and the compression action of the screw promote physical and chemical reactions between the components. For example, taking silver antibacterial agent as an example, the silver ions (Ag⁺) on its surface have strong positive charges. There are a small number of polar groups such as carbonyl (C=O) and hydroxyl (-OH) on the molecular chain of polypropylene resin. The oxygen atoms of these groups have lone pairs of electrons and carry a certain negative charge. The silver ions (Ag⁺) combine with the oxygen atoms of the hydroxyl groups on the surface of polypropylene resin through electrostatic attraction and coordination to form relatively stable coordination bonds. Through these reactions, the silver-based antibacterial agent is fixed on the surface of the hydrophobic masterbatch and polypropylene resin. On the one hand, it improves the dispersion stability of the antibacterial agent in the material. On the other hand, when bacteria come into contact with the material surface, silver ions can be continuously released, destroying the cell membrane and respiratory enzyme system of bacteria, enhancing the stability and dispersion of the antibacterial agent in the material, and achieving high-efficiency antibacterial. In the compression section, the antioxidant can capture the free radicals generated in the system at high temperature, inhibiting the oxidation reaction of polypropylene resin and other components, preventing the material from aging and performance degradation due to oxidation during processing and use. The lubricant can form a lubricating film between the material and the screw and barrel, reducing the flow resistance of the material, reducing energy consumption, and improving production efficiency. At the same time, the lubricant can also improve the surface performance of the material, preventing the material from sticking to the wall during the extrusion process and ensuring the surface quality of the extruded product.

[0020] The homogenizing section maintains a temperature of 180 - 190 °C to ensure that the material reaches a uniform state before extrusion. In the homogenizing section, the rotation of the screw and the flow of the material further promote the mixing and dispersion of each component, making the temperature, composition, and structure inside the material more uniform. Appropriate screw speed, feeding rate, and length-diameter ratio ensure the residence time of the material in the extruder and the mixing effect, achieving the full fusion of each component; the screw speed is 300 - 500 r / min, the feeding rate is 50 kg / h, and the length-diameter ratio of the twin-screw extruder is 44 - 60:1. These parameters cooperate with each other, enabling the material to undergo sufficient melting, mixing, chemical reaction, and homogenization processes in the extruder; compared with the prior art method of directly mixing and extruding all raw materials, the present invention improves the dispersion uniformity of each component and the comprehensive performance of the material by first preliminarily mixing in a high-speed mixer and then further processing in a twin-screw extruder.

[0021] Further, the antibacterial agent is selected from any one or a mixture of two or more of silver-based antibacterial agents, zinc-based antibacterial agents, and copper-containing antibacterial agents.

[0022] Further, the zinc-based antibacterial agent is any one or a mixture of two or more of 2-pyridinethiol-1-oxide zinc, zinc pyrithione, zinc thiazole, bis(8-hydroxyquinoline)zinc, zinc oxide, nano-zinc oxide, and zinc sulfate.

[0023] Further, the antioxidant is any one or a mixture of two or more of tris(2,4-di-tert-butylphenyl) phosphite, pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,6-di-tert-butyl-p-cresol, tert-butyl-p-hydroxyanisole, tert-butylhydroquinone, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, vitamin E, phosphite ester, dilauryl thiodipropionate, distearyl thiodipropionate, zinc dimethyldithiocarbamate, calcium stearate, and zinc stearate.

[0024] Further, the lubricant is any one or a mixture of two or more of ethylene bisstearamide, pentaerythritol stearate, calcium stearate, zinc stearate, glycerol monostearate, and glycerol tristearate.

[0025] Further, based on the mass of the fluorine-free hydrophobic modified plastic with antibacterial effect as a percentage benchmark, the hydrophobizing agent content is 0.5 - 4%; within this content range, the hydrophobizing agent can form an effective hydrophobic layer on the material surface, endowing the material with good hydrophobic properties, while avoiding the problem of increased material cost caused by too high a content of the hydrophobizing agent. When the content of the hydrophobizing agent is less than 0.5%, a continuous hydrophobic layer cannot be formed on the material surface, and the hydrophobic effect is poor; while when the content of the hydrophobizing agent is higher than 4%, it will cause the hydrophobizing agent to agglomerate in the material, affecting the uniformity and other properties of the material. By precisely controlling the content of the hydrophobizing agent, the present invention takes into account other properties and cost-effectiveness of the material while ensuring the hydrophobic properties of the material. Compared with the prior art process of achieving hydrophobic effect by increasing the content of the hydrophobizing agent, the present invention can provide a hydrophobic antibacterial material with better performance and lower cost.

[0026] Further, a boiling water resistance test is carried out on the fluorine-free hydrophobic modified plastic sample with antibacterial effect. The sample is divided into four groups. The first group is boiled in water at 70°C for 1000 h; the second group is boiled in water at 70°C and detergent is added for 1000 h; the third group is boiled in water at 100°C for 168 h; the fourth group is boiled in water at 100°C and detergent is added for 168 h. After the boiling water resistance test, the sample is taken out for contact angle measurement. The sample is gently wiped with a clean gauze dipped in an appropriate amount of ethanol, and then the sample is placed in a drying oven and dried at 50°C for 2 h. A contact angle measuring instrument of Shanghai Yingnuo Precision Instrument Co., Ltd. is used for contact angle measurement. The diameter of the needle of the contact angle measuring instrument is 0.5 - 1.0 mm. The surface contact angle of the fluorine-free hydrophobic modified plastic with antibacterial effect is 113° - 115°. After boiling in water at 70°C for 1000 h, the contact angle is 109° - 113°. After boiling in water at 100°C for 168 h, the contact angle is 106° - 110°. Through the boiling water resistance test, the high-temperature and high-humidity environment that the material may encounter during actual use is simulated to verify the persistence of the hydrophobic properties of the material. The experimental results show that the fluorine-free hydrophobic modified plastic with antibacterial effect of the present invention can still maintain a relatively high contact angle after long-term boiling and the action of detergent, indicating that the hydrophobic layer of the material has good stability. This is due to the effective loading and fixation of the hydrophobizing agent by the adsorbent in the hydrophobic masterbatch, as well as the strong bonding between the hydrophobizing agent and the material matrix. Compared with the materials in the prior art whose hydrophobic properties rapidly decline in high-temperature and high-humidity environments, the materials of the present invention have more excellent long-term stain resistance performance and can meet the requirements for material durability in actual applications.

[0027] An antibacterial experiment was conducted on the fluorine-free hydrophobic modified plastic sample with antibacterial effect. The sample was taken as the test article. First, the test article was sterilized by soaking it in a 70% ethanol solution, taken out after 1 min, rinsed with sterile water, and air-dried naturally. A 0.2 mL suspension of Staphylococcus aureus (5×10 5 CFU / mL) was dropped onto the test article and the control sample. The control sample was made of hygienic high-density polyethylene (HDPE). The test article surface was covered with a sterilized covering film to make the bacterial suspension contact the sample evenly. The temperature was set at 37±1°C and the relative humidity RH>90%. After culturing for 24±1 h, the test article and the control sample were taken out. The test article, the control sample, and the covering film were repeatedly washed with 20 mL of eluent. The eluent was collected in a volumetric flask, shaken well, then serially diluted and inoculated into a nutrient agar medium. After culturing at 37±1°C for 24 - 48 h, viable counts were performed to determine the number of viable bacteria in the eluent. The calculation formula for the antibacterial rate is:

[0028] Under experimental conditions, the fluorine-free hydrophobic modified plastic with antibacterial effect of the present invention can effectively inhibit the growth of Staphylococcus aureus and has a high antibacterial rate. This benefits from the hydrophobic masterbatch and the two-step preparation method. In the hydrophobic masterbatch, supercritical foamed polypropylene adsorbs the hydrophobic agent to form a stable and efficient hydrophobic structure, effectively reducing the water environment for bacteria to survive and decreasing the attachment amount of bacteria on the material surface. At the same time, the two-step preparation method avoids the conflict caused by the direct mixing of the hydrophobic agent and the antibacterial agent, ensures the activity of the antibacterial agent, and promotes the uniform dispersion of each component. The two work synergistically to endow the material with strong antibacterial ability in a humid environment, showing prominent advantages compared with the hydrophobic agents prepared by the prior art.

[0029] An environmental treatment device includes the aforementioned fluorine-free hydrophobic modified plastic with antibacterial effect. The environmental treatment device is applied to at least one of the following scenarios: 1. Functional components in liquid or gas medium treatment devices that are in direct contact with the medium; in liquid or gas medium treatment devices, the components in direct contact with the medium are easily contaminated by impurities and microorganisms in the medium. The fluorine-free hydrophobic modified plastic with antibacterial effect of the present invention has excellent hydrophobic and antibacterial properties, which can effectively prevent the liquid medium from adhering to and remaining on the component surface, reducing the breeding environment for impurities and microorganisms. At the same time, the antibacterial property can inhibit the growth and reproduction of microorganisms in the medium on the component surface and prevent the formation of biofilms, thus ensuring the normal operation and treatment effect of the device and extending the service life of the device; 2. Fluid delivery components in a closed environment with high temperature, high humidity or prone to microbial growth; in a closed environment with high temperature, high humidity or prone to microbial growth, fluid delivery components are susceptible to corrosion and microbial contamination. The materials of the present invention have good temperature resistance and hydrophobic properties, can maintain stable hydrophobic properties in high temperature and high humidity environments, prevent moisture from accumulating on the surface of the components, and reduce the corrosion risk; at the same time, the antibacterial property can effectively inhibit the growth of microorganisms on the surface of the components, avoid problems such as pipeline blockage and poor fluid delivery caused by microbial contamination, and improve the efficiency and reliability of fluid delivery. 3. Cleaning, disinfection or filtration devices that need to inhibit biofilm formation or pollutant residue; in cleaning, disinfection or filtration devices, inhibiting biofilm formation and pollutant residue is the key to ensuring the normal operation and treatment effect of the devices. The fluorine-free hydrophobic modified plastic with antibacterial effect of the present invention can reduce the attachment of pollutants on the surface of the devices through hydrophobic properties and inhibit the formation of biofilms through antibacterial properties, thereby improving the cleaning efficiency and filtration effect of the devices and reducing the maintenance cost.

[0030] Advantages of the present invention 1. The unique structure of supercritical foamed polypropylene provides an ideal carrier matrix for the hydrophobic agent. It has a uniform microporous structure with a size of 1 - 0 μm, increasing the specific surface area of the material to 10 - 50 m² / g. Its arithmetic mean deviation of the profile Ra is 5 - 10 μm, and the rough surface provides a large number of sites for the attachment of the hydrophobic agent. The particle size of the emulsion-like aminopolysilane hydrophobic agent is between 0.5 - 1 µm, which is compatible with the micropore size of supercritical foamed polypropylene, ensuring that the aminopolysilane can smoothly enter the interior of the micropores; from the molecular structure, the nitrogen atom in the amino group (-NH2) of aminopolysilane is rich in lone pair electrons, and the oxygen atoms in the hydroxyl group (-OH) and carbonyl group (C=O) of supercritical foamed polypropylene also have lone pair electrons. Due to the significant electronegativity difference between the amino group and these groups, hydrogen bonds will be formed. At the same time, there are van der Waals forces between the amino group and silyl group (-SiR3) of aminopolysilane and the methylene group (-CH2) and methyl group (-CH3) of supercritical foamed polypropylene. Under the synergistic action of these two intermolecular forces, the aminopolysilane forms a tight adsorption layer on the surface of the micropores of supercritical foamed polypropylene and gradually diffuses deep into the micropores by overcoming the intermolecular resistance through capillary action. When the aminopolysilane is cured, it forms a stable mechanical interlocking structure with supercritical foamed polypropylene. Material mechanics tests show that the bonding strength of this structure is increased by more than 30% compared with ordinary physical adsorption. The data of the boiling water resistance test shows that the initial contact angle of the modified plastic containing this hydrophobic masterbatch is between 113° and 115°. After boiling at 70°C for 1000 h, the contact angle can still be maintained between 109° and 113°. After boiling at 100°C for 168 h, the contact angle range is 106° - 110°. In addition, the 1000 - cycle flushing test under the simulated washing environment shows that after experiencing high temperature, high pressure and the chemical erosion of the detergent, the hydrophobic property of the material remains stable. During the actual use of washing products, whether in the hand - washing or machine - washing environment, the material can continuously maintain the hydrophobic state, prevent water and detergent from adhering for a long time, and avoid the material aging and performance degradation caused by chemical substance erosion.

[0031] 2. In the traditional material preparation process, the direct mixing of hydrophobic agents and antibacterial agents will cause a series of problems. Taking 2 - pyridinethiol - 1 - zinc oxide and amino polysilane as examples, according to the theory of coordination chemistry and intermolecular forces, Zn in 2 - pyridinethiol - 1 - zinc oxide 2+ has empty orbitals, while the amino group of amino polysiloxane has lone pair electrons, and the two are very likely to undergo a coordination reaction. At the same time, hydrogen bonds will be formed between the nitrogen and sulfur atoms in 2 - pyridinethiol and the amino group of amino polysiloxane, and electrostatic interactions will occur. These interactions will seriously interfere with the molecular arrangement of the hydrophobic agent, making it impossible for the hydrophobic groups to form an effective covering layer on the material surface, resulting in a significant decrease in the hydrophobic property of the material. In addition, this interaction changes the chemical environment of the antibacterial agent, reduces the ability of the antibacterial agent to effectively interact with bacterial cells, and weakens the antibacterial effect. The present invention adopts a two - step preparation process of "first preparing the hydrophobic masterbatch and then preparing the modified plastic", which successfully solves this problem: when preparing the hydrophobic masterbatch in the first step, the hydrophobic agent, adsorbent and synthetic resin are fully mixed under specific process conditions to form a stable structure. In the low - speed mixing pot stage, stir at a stirring rate of 100 - 200 r / min for 2 - 10 min to ensure that the hydrophobic agent is evenly adsorbed on the surface of the adsorbent. In the high - speed mixing pot stage, stir at a stirring rate of 150 - 300 r / min for 2 - 5 min to make the adsorbed hydrophobic agent fully fuse with the synthetic resin. When mixing the hydrophobic masterbatch with other components such as antibacterial agents in the second step, since the hydrophobic agent has formed a stable structure in the masterbatch, the direct contact with the antibacterial agent is reduced, effectively avoiding the mutual interference between the two, and ensuring that the hydrophobic agent and the antibacterial agent can play their roles independently. The antibacterial performance test in the environment of a bacteria - containing washing liquid shows that the antibacterial rate of the material of the present invention against Staphylococcus aureus reaches more than 99%. For the material prepared by the traditional direct - mixing process, the antibacterial rate is only about 60%. This significant difference shows that the two - step preparation process of the present invention effectively meets the strict requirements of washing products for hygienic performance, and can effectively inhibit the growth of bacteria in washing products that are in close contact with the human body, such as dishcloths and shower curtains, and ensure the health of users.

[0032] 3. The two-step preparation process of the present invention comprehensively optimizes the production process. From raw material mixing to extrusion granulation, the parameters of each link are precisely controlled. In the raw material mixing stage, the combined use of a low-speed mixer and a high-speed mixer can control the stirring rate and time according to the characteristics of different raw materials to achieve uniform dispersion of each component. The stirring rate of the low-speed mixer is controlled at 100-200 r / min, which enables the water repellent and adsorbent to fully contact in a relatively mild environment, facilitating the adsorption of the water repellent on the surface of the adsorbent. The stirring rate of the high-speed mixer is increased to 150-300 r / min, which can quickly disperse the adsorbed water repellent in the synthetic resin. In the extrusion granulation stage, parameters such as the temperature, screw speed, and feeding rate of the twin-screw extruder play a crucial role in product quality and production efficiency. The temperature of the conveying section is controlled at 160-170 °C, which can not only ensure that the material has a certain fluidity for smooth conveying but also avoid the decomposition or volatilization of the heat-sensitive components in the water repellent due to excessive temperature. The temperature of the compression section is increased to 180-190 °C. Under the action of high temperature and high pressure, the material further melts, and the intermolecular interaction is enhanced, improving the uniformity of the material. The homogenization section maintains a temperature of 170-180 °C to ensure that the temperature and composition of the material are uniform before extrusion. The screw speed is set at 400-600 r / min, the feeding rate is 40-80 kg / h, and the length-diameter ratio of the twin-screw extruder is 44-60:1. These parameters cooperate with each other to ensure that the material has sufficient residence time in the extruder to achieve full melting, mixing, and plasticization. Large-scale production comparison experiments show that the production cycle of the process of the present invention is shortened by 30% compared with the traditional process. In the traditional process, due to the uneven mixing of each component, longer time is required for stirring and adjustment, resulting in low production efficiency. However, through precise parameter control, the process of the present invention improves the controllability of the production process and significantly increases the production efficiency. In terms of the finished product quality, the qualified rate of the products of the process of the present invention reaches over 98%, which is increased by 20% compared with the traditional process. In the traditional process, due to uneven mixing and improper parameter control, it is easy to cause defects in the products, such as rough surfaces and internal bubbles, thus reducing the qualified rate of the finished products. The process of the present invention effectively reduces the generation of waste, lowers the production cost, ensures the consistency of product quality, conforms to the development trend of cost reduction and efficiency increase in modern industry, and is conducive to the large-scale industrial production of washing products.

[0033] 4. Different from the prior art that uses fluorine-containing raw materials, the present invention completely abandons fluorine-containing components. Fluorine-containing raw materials can generate a large amount of greenhouse gases during the production process, causing damage to the ozone layer; during use, fluorine leakage may occur, causing serious harm to the ecological environment and human health; during the waste treatment process, fluorine-containing materials are difficult to degrade and will exist in the environment for a long time, causing environmental pollution. In the production process of the materials of the present invention, the risk of fluorine leakage is eliminated from the source, reducing the potential threat to the environment. The simulated natural degradation experiment shows that the degradation rate of the materials of the present invention in the soil is more than 3 times faster than that of fluorine-containing materials. Through thermogravimetric analysis and infrared spectroscopy analysis, it is found that in the natural environment, the molecular chains of the materials of the present invention will gradually break and decompose into small molecular substances, which are absorbed and utilized by microorganisms in the soil. In addition, the energy consumption during the production process of the materials of the present invention is relatively low. By optimizing the production equipment and adjusting the process parameters, the energy consumption is reduced, meeting the requirements of energy conservation and emission reduction. After the washing products are discarded, the materials of the present invention can degrade faster, reducing environmental pollution. Taking a plastic laundry basin as an example, the laundry basin made of the materials of the present invention can be naturally degraded in a relatively short time after being discarded, reducing the pressure on the environment caused by solid waste. This characteristic provides technical support for the research and development and application of green washing products, promoting the development of the washing product industry towards a more environmentally friendly and sustainable direction. In summary, the present invention has significant advantages in terms of hydrophobicity, antibacterial property, production process and environmental protection. With its performance advantages demonstrated in the washing scenario, it can not only meet the needs of consumers for high-quality and high-safety washing products, but also bring significant economic benefits to enterprises, and has broad application prospects and social and economic benefits in the field of washing products. With the continuous development and improvement of technology, the present invention is expected to occupy an important position in the washing product market and lead the innovative development of the industry. Brief Description of the Drawings

[0034] Figure 1 It is a schematic flow chart of the preparation of the hydrophobic masterbatch; The figure shows the key process of preparing the hydrophobic masterbatch of the present invention. On the left side, the adsorbent presents a porous structure, and these pores are ideal loading sites for the hydrophobic agent; the hydrophobic agent exists in the form of red spherical particles. When the adsorbent is mixed with the hydrophobic agent, based on the adsorption principle, the hydrophobic agent fills into the pores of the adsorbent step by step through physical adsorption and a small amount of chemical adsorption with the help of the porous structure of the adsorbent, achieving uniform dispersion; subsequently, the adsorbent loaded with the hydrophobic agent is mixed with polypropylene (PP). As a common polymer material, polypropylene has good processing performance and physical stability. During the mixing process, the adsorbent particles loaded with the hydrophobic agent are evenly dispersed in the polypropylene system, and finally form hydrophobic masterbatch through processes such as melt blending. From a technical principle perspective, the porous structure of the adsorbent significantly increases the specific surface area, providing a large number of attachment sites for the water repellent, enhancing the interaction between the water repellent and the adsorbent, and improving the loading stability. Physical adsorption is based on the van der Waals force between molecules and can quickly achieve the attachment of the water repellent on the surface and within the pores of the adsorbent; the possible small amount of chemical adsorption, such as hydrogen bonding and weak chemical bonds, further consolidates the binding between the water repellent and the adsorbent; this preparation process brings outstanding technical effects. On the one hand, it ensures the highly uniform dispersion of the water repellent in the masterbatch, and when applied to detergents subsequently, the surface of the product can have consistent hydrophobic properties everywhere, avoiding the situation of poor local hydrophobic effects. On the other hand, the stable loading structure ensures that the water repellent is not easily detached or migrated under different environments. When the detergent undergoes complex conditions such as multiple washes, high temperatures, and friction, it can still maintain good hydrophobic properties, extend the service life of the product, and improve the reliability and durability of the product in actual use scenarios. In addition, this preparation process is simple and efficient, easy to industrialize on a large scale, reduces production costs, and is conducive to the promotion and application of the product in the market. Detailed implementation manners

[0035] To better explain the present invention, the exemplary embodiments of the present invention will be described in more detail below. Although the exemplary embodiments of the present invention are shown below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to be able to convey the scope of the present invention completely to those skilled in the art.

[0036] Examples 1-3 use amino silicone as the water repellent and supercritical foamed polypropylene as the adsorbent, with only differences in the addition amounts. Example 1 Prepare the water-repellent masterbatch sample 1 Step 1: Add 5 parts of amino silicone and 5 parts of supercritical foamed polypropylene to a low-speed mixer and stir for 5 minutes at a stirring rate of 150 r / min to obtain the adsorbed water repellent 1. Then, add the adsorbed water repellent 1 and 90 parts of polypropylene resin with an average molecular weight of 400,000 to a high-speed mixer and stir for 5 minutes at a stirring rate of 300 r / min to obtain the masterbatch 1; Step 2: Add the masterbatch 1 to a twin-screw extruder for extrusion granulation to obtain the water-repellent masterbatch 1. Among them, the length-diameter ratio of the twin-screw extruder is 44:1, the processing temperature of the feeding section is set at 155 °C, the processing temperature of the conveying section is 200 °C, the processing temperature of the compression section is 190 °C, the processing temperature of the homogenization section is 185 °C, the die head temperature is 200 °C, the screw speed is 500 r / min, the feeding rate is 50 kg / h, and the particle size of the obtained water-repellent masterbatch is 3-7 mm; Example 2 Preparation of hydrophobic masterbatch sample 2 Step 1: Add 20 parts of amino silicone and 20 parts of supercritical foamed polypropylene to a low-speed mixer and stir for 5 minutes at a stirring rate of 150 r / min to obtain the adsorbed hydrophobic agent 2. Then, add the adsorbed hydrophobic agent 2 and 60 parts of polypropylene resin with an average molecular weight of 400,000 to a high-speed mixer and stir for 5 minutes at a stirring rate of 300 r / min to obtain masterbatch 2; Step 2: Add the masterbatch 2 into a twin-screw extruder for extrusion granulation to obtain hydrophobic masterbatch 2. Among them, the ratio of the length to the diameter of the twin-screw extruder is 44:1. Set the feeding section at 155 °C, the processing temperature of the conveying section at 200 °C, the processing temperature of the compression section at 190 °C, the processing temperature of the homogenization section at 185 °C, the die head at 200 °C, the screw speed at 500 r / min, and the feeding rate at 50 kg / h. The particle size of the obtained hydrophobic masterbatch is 3 - 7 mm; Example 3 Preparation of hydrophobic masterbatch sample 3 Step 1: Add 40 parts of amino silicone and 40 parts of supercritical foamed polypropylene to a low-speed mixer and stir for 5 minutes at a stirring rate of 150 r / min to obtain the adsorbed hydrophobic agent 2. Then, add the adsorbed hydrophobic agent 3 and 20 parts of polypropylene resin with an average molecular weight of 400,000 to a high-speed mixer and stir for 5 minutes at a stirring rate of 300 r / min to obtain masterbatch 3; Step 2: Add the masterbatch 3 into a twin-screw extruder for extrusion granulation to obtain hydrophobic masterbatch 3. Among them, the ratio of the length to the diameter of the twin-screw extruder is 44:1. Set the feeding section at 155 °C, the processing temperature of the conveying section at 200 °C, the processing temperature of the compression section at 190 °C, the processing temperature of the homogenization section at 185 °C, the die head at 200 °C, the screw speed at 500 r / min, and the feeding rate at 50 kg / h. The particle size of the obtained hydrophobic masterbatch is 3 - 7 mm; Example 4: Using amino silicone as the hydrophobic agent and activated carbon as the adsorbent Preparation of hydrophobic masterbatch sample 4 Step 1: Add 20 parts of amino silicone and 20 parts of activated carbon to a low-speed mixer and stir for 5 minutes at a stirring rate of 150 r / min to obtain the adsorbed hydrophobic agent 4. Then, add the adsorbed hydrophobic agent 4 and 60 parts of polypropylene resin with an average molecular weight of 400,000 to a high-speed mixer and stir for 5 minutes at a stirring rate of 300 r / min to obtain masterbatch 4; Step 2: Add the masterbatch 4 into a twin-screw extruder for extrusion granulation to obtain the hydrophobic masterbatch 4. The length-diameter ratio of the twin-screw extruder is 44:1. Set the processing temperature of the feeding section at 155°C, the conveying section at 200°C, the compression section at 190°C, the homogenization section at 185°C, and the die head at 200°C. The screw speed is 500 r / min, and the feeding rate is 50 kg / h. The particle size of the obtained hydrophobic masterbatch 4 is 3 - 7 mm; Example 5: Compound Different Hydrophobic Agents Prepare the hydrophobic masterbatch sample 5 Step 1: Add 10 parts of amino silicone oil, 10 parts of long-chain alkylsilane, and 20 parts of supercritical foamed polypropylene into a low-speed mixer and stir for 5 min at a stirring rate of 150 r / min to obtain the adsorbed hydrophobic agent 5. Then add the adsorbed hydrophobic agent 5 and 60 parts of polypropylene resin with an average molecular weight of 400,000 into a high-speed mixer and stir for 5 min at a stirring rate of 300 r / min to obtain the masterbatch 5; Step 2: Add the masterbatch 5 into a twin-screw extruder for extrusion granulation to obtain the hydrophobic masterbatch 5. The length-diameter ratio of the twin-screw extruder is 44:1. Set the processing temperature of the feeding section at 155°C, the conveying section at 200°C, the compression section at 190°C, the homogenization section at 185°C, and the die head at 200°C. The screw speed is 500 r / min, and the feeding rate is 50 kg / h. The particle size of the obtained hydrophobic masterbatch 5 is 3 - 7 mm; Examples 6 - 10: Prepare Fluorine-free Hydrophobic Modified Plastics 1 - 5 with Antibacterial Effect Using the Hydrophobic Masterbatches in Examples 1 - 5 Add 10 parts of the hydrophobic masterbatches 1 - 5, 5 parts of copolymerized polypropylene resin with an average molecular weight of 400,000, 83.5 parts of homopolypropylene resin with an average molecular weight of 350,000, 0.5 part of 2-pyridinethiol-1-zinc oxide, 0.3 part of tris(2,4-di-tert-butylphenyl) phosphite, 0.2 part of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 0.3 part of vinyl bisstearamide, and 0.2 part of pentaerythritol stearate into a high-speed mixer and mix for 5 min to obtain a mixture at a stirring rate of 300 r / min. Then add the mixture into a twin-screw extruder from the main feeding port to obtain the fluorine-free hydrophobic modified plastics 1 - 5 with antibacterial effect. The length-diameter ratio of the twin-screw extruder is 44:1. Set the processing temperature of the feeding section at 155°C, the conveying section at 200°C, the compression section at 190°C, the homogenization section at 185°C, and the die head at 200°C. The screw speed is 500 r / min, and the feeding rate is 50 kg / h.

[0037] Based on the mass of the fluorine-free hydrophobic modified plastic 1 with antibacterial effect, the loading amount of the hydrophobic agent 1 is 0.5%; Based on the mass of the fluorine-free hydrophobic modified plastic 2 with antibacterial effect, the loading amount of the hydrophobic agent 2 is 2%; Based on the mass of the fluorine-free hydrophobic modified plastic 3 with antibacterial effect, the loading amount of the hydrophobic agent 3 is 4%; Based on the mass of the fluorine-free hydrophobic modified plastic 4 with antibacterial effect, the loading amount of the hydrophobic agent 4 is 2%; Based on the mass of the fluorine-free hydrophobic modified plastic 5 with antibacterial effect, the loading amount of the hydrophobic agent 5 is 2%. Comparative Example 1: Without adsorbent Preparation of modified PP material 1 Step 1: Add 80 parts of polypropylene resin with an average molecular weight of 400,000 and 20 parts of amino silicone to a low-speed mixer and stir for 5 min at a stirring rate of 150 r / min to uniformly mix the polypropylene resin and amino silicone to obtain a masterbatch. Add the masterbatch to a twin-screw extruder for extrusion granulation to obtain hydrophobic masterbatch 6; wherein, the length-diameter ratio of the twin-screw extruder is 44:1, set the feeding section at 155 °C, the processing temperature of the conveying section at 200 °C, the processing temperature of the compression section at 190 °C, the processing temperature of the homogenization section at 185 °C, the die head at 200 °C, the screw speed at 400 - 600 r / min, the feeding rate at 50 kg / h, and the particle size of the obtained hydrophobic masterbatch is 3 - 7 mm; Step 2: Add 10 parts of the hydrophobic masterbatch 6, 5 parts of copolymerized PP with an average molecular weight of 400,000, 83.5 parts of homopolymerized PP with an average molecular weight of 350,000, 0.5 part of 2-pyridinethiol-1-zinc oxide, 0.3 part of tris(2,4-di-tert-butylphenyl) phosphite, 0.2 part of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.3 part of vinyl bisstearamide, and 0.2 part of pentaerythritol stearate to a high-speed mixer and mix for 5 min to obtain a mixture at a stirring rate of 300 r / min. Then add the mixture to the twin-screw extruder from the main feeding port to obtain the modified PP material 1. Based on the mass of the modified PP material 1, the loading amount of the hydrophobic agent is 2%; the length-diameter ratio of the twin-screw extruder is 44:1, set the feeding section at 155 °C, the processing temperature of the conveying section at 200 °C, the processing temperature of the compression section at 190 °C, the processing temperature of the homogenization section at 185 °C, the die head at 200 °C, the screw speed at 500 r / min, and the feeding rate at 50 kg / h.

[0038] Comparative Example 2: The hydrophobic agent and the antibacterial agent are directly mixed and there is no adsorbent Preparation of modified PP material 2 Add 15 parts of copolymerized PP with an average molecular weight of 400,000, 83.5 parts of homopolymerized PP with an average molecular weight of 350,000, 2 parts of amino silicone, 0.5 part of 2-pyridinethiol-1-zinc oxide, 0.3 part of tris(2,4-di-tert-butylphenyl) phosphite, 0.2 part of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.3 part of vinyl bisstearamide, and 0.2 part of pentaerythritol stearate into a high-speed mixer and mix for 5 min to obtain a mixture. The stirring rate is 300 r / min. Then add the mixture into a twin-screw extruder from the main feeding port to obtain the modified PP material 2. Based on the mass percentage of the modified PP material 2, the loading amount of the water repellent is 2%. Among them, the ratio of the length to the diameter of the twin-screw extruder is 44:1. Set the feeding section at 155 °C, the processing temperature of the conveying section at 200 °C, the processing temperature of the compression section at 190 °C, the processing temperature of the homogenization section at 185 °C, the die head at 200 °C, the screw speed at 400 - 600 r / min, and the feeding rate at 50 kg / h.

[0039] Comparative Example 3, without water repellent Prepare modified PP material 3 Add 15 parts of copolymerized PP with an average molecular weight of 400,000, 83.5 parts of homopolymerized PP with an average molecular weight of 350,000, 0.5 part of 2-pyridinethiol-1-zinc oxide, 0.3 part of tris(2,4-di-tert-butylphenyl) phosphite, 0.2 part of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.3 part of vinyl bisstearamide, and 0.2 part of pentaerythritol stearate into a high-speed mixer and mix for 5 min to obtain a mixture. The stirring rate is 300 r / min. Then add the mixture into a twin-screw extruder from the main feeding port to obtain the modified PP material 2. Among them, the ratio of the length to the diameter of the twin-screw extruder is 44:1. Set the feeding section at 155 °C, the processing temperature of the conveying section at 200 °C, the processing temperature of the compression section at 190 °C, the processing temperature of the homogenization section at 185 °C, the die head at 200 °C, the screw speed at 400 - 600 r / min, and the feeding rate at 50 kg / h.

[0040] Contact angle measurement Perform contact angle tests on the samples of Examples 6 - 10 and Comparative Examples 1 - 3 respectively. Dip a clean gauze in an appropriate amount of ethanol and gently wipe the surface of the samples. Then put the samples into a drying oven and dry them at 50 °C for 2 h. Select a contact angle measuring instrument from Shanghai Yingnuo Precision Instrument Co., Ltd. The diameter of the needle head is 0.5 mm, the test liquid is pure water, and the contact angle measurement results are shown in Table 1.

[0041] Boiling water resistance experiment The samples of Examples 6-10 and Comparative Examples 1-3 were respectively divided into four groups. The first group was added to water at 70 °C and boiled for 1000 h; the second group was added to water at 70 °C and detergent (Kao detergent) was added to a concentration of 2.5 wt% and boiled for 1000 h; the third group was added to water at 100 °C and boiled for 168 h; the fourth group was added to water at 100 °C and detergent (Kao detergent) was added to a concentration of 2.5 wt% and boiled for 168 h. After the boiling water resistance test, the samples of Examples 4-6 and Comparative Examples 2-4 were taken out and contact angle tests were carried out. The contact angle measurement results are shown in Table 1.

[0042] Antibacterial experiment The samples of Examples 6-10 and Comparative Examples 1-3 were used as test samples. First, the test samples were sterilized, soaked in 70% ethanol solution, taken out after 1 min, rinsed with sterile water, and dried naturally; 0.2 mL of Staphylococcus aureus (5×10 5 CFU / mL) suspension was dropped onto the test samples and control samples. The control samples were made of hygienic high-density polyethylene (HDPE). The test samples were covered with a sterilized covering film to make the bacterial suspension evenly contact the samples. The temperature was set at 37 ± 1 °C and the relative humidity RH > 90%. After culturing for 24 ± 1 h, the test samples and control samples were taken out. The test samples, control samples and covering film were repeatedly washed with 20 mL of eluent. The eluent was collected in a volumetric flask, shaken well, then gradient diluted and inoculated into nutrient agar medium. After culturing at 37 ± 1 °C for 24-48 h, viable cell counting was carried out to determine the viable cell count in the eluent. The calculation formula for the antibacterial rate is:

[0043] The antibacterial rate is shown in Table 1.

[0044] Table 1. Contact angle of boiling water resistance test (test standard: GB / T 30693-2014) and antibacterial rate test results (test standard: GB / T 30693-2014).

[0045]

[0046] As can be clearly seen from the data in Table 1, compared with Comparative Example 3 without a hydrophobic agent, all Examples (Examples 6 - 10) with a hydrophobic agent showed a significant increase in the contact angle. The initial contact angle of Comparative Example 3 was only 88.7°, belonging to hydrophilic materials, while the initial contact angles of Examples 6 - 10 were all greater than 90°. Among them, Examples 7 - 10 reached about 114°, Example 6 was 102.4°, and Example 9 was 113.8°. This fully indicates that the hydrophobic agent plays a key role in improving the hydrophobic performance of polypropylene materials. The hydrophobic agent can form a low surface energy layer on the material surface, reduce the interfacial tension between the material surface and water, thereby increasing the contact angle and making the material hydrophobic.

[0047] Further comparing Examples 6 - 10 of the present invention with Comparative Example 1 directly adding a hydrophobic agent, it can be found that the Examples are extremely effective in improving hydrophobicity. Taking the test results after boiling in water with detergent at 70°C for 1000 h as an example, the hydrophobicity of Comparative Example 1 decreased by 10%, and the contact angle dropped to 103.7°; while among Examples 6 - 10, the largest decrease was 3% in Example 6, and the contact angle still remained at 99.8°, the decrease in Example 9 was 3%, and the contact angle was 110.2°, and the decrease in Example 10 was 2%, and the contact angle was 111.8°. This further verifies that there are drawbacks in the method of directly adding a hydrophobic agent, where components such as antibacterial agents and antioxidants will damage the original hydrophobic structure formed by the hydrophobic agent, thereby weakening the hydrophobic effect; on the contrary, the present invention uses hydrophobic masterbatches to prepare stain-resistant materials, successfully avoiding the interference of antibacterial agents to the hydrophobic agent, effectively ensuring the hydrophobicity of the material, and fully demonstrating the superiority of the preparation process of the present invention.

[0048] Deeply analyzing the differences between Example 7, Example 10, and Comparative Example 2, when the content of the hydrophobic agent is the same (both 2%), the hydrophobic masterbatch of Comparative Example 2 does not add supercritical foamed polypropylene as an adsorbent. The experimental results show that after high-temperature boiling, especially in the case of adding detergent, the hydrophobic effect of Comparative Example 2 decreased more significantly than that of Examples 7 and 10. For example, after boiling in water with detergent at 100°C for 168 h, the contact angle of Comparative Example 2 was 97.3°, and the hydrophobicity decreased by 15%; while the contact angle of Example 7 was 108.2, and the contact angle of Example 10 was 108.5°, and the decrease was only 5% in both cases. This phenomenon strongly confirms that the unique porous structure of supercritical foamed polypropylene can provide abundant adsorption sites for the hydrophobic agent, thereby increasing the loading amount of the hydrophobic agent; moreover, after the hydrophobic agent is cured, it will be embedded in the matrix of the foamed polypropylene material to form a stable mechanical interlocking structure, greatly enhancing the bonding strength between the two, effectively preventing the hydrophobic agent from precipitating from the material surface, avoiding the problem of hydrophobic failure, and significantly improving the hydrophobic performance of the material.

[0049] From the comparison of Examples 6 - 8, it can be seen that when the content of the hydrophobic agent is too low (the content of the hydrophobic agent in Example 6 is 0.5%), the hydrophobic effect is poor, and the initial contact angle of Example 6 is only 102.4°; while for the hydrophobic masterbatch with too high content (the content of the hydrophobic agent in Example 8 is 4%), the improvement of the effect is not obvious. Moreover, after the boiling water test, when the content of the hydrophobic agent is too high (4%) and too low (0.5%), the hydrophobic effect decreases significantly. For example, after boiling in water with detergent at 100°C for 168 h in Example 6, the contact angle drops to 97.1°, with a decrease amplitude of 5%. Under the same conditions in Example 8, the contact angle drops to 107.7°, with a decrease amplitude of 6%. Thus, it can be seen that when the content of the hydrophobic agent is 2%, the hydrophobic effect is relatively good. The contact angles and the decrease amplitudes of hydrophobicity of Examples 7, 9, and 10 under various test conditions are all relatively ideal, which also verifies that the special structural design of the present invention unexpectedly enables an efficient and long - lasting hydrophobic effect to be achieved when the loading amount of the hydrophobic agent is relatively low.

[0050] In terms of antibacterial performance, the antibacterial rates of Examples 6 - 10 before treatment all reach 99.9%, showing high inhibitory ability against Staphylococcus aureus. After boiling in water with detergent at 70°C for 1000 h, the antibacterial rates of Examples 6 - 10 still remain at 99.9%, while the antibacterial rate of Comparative Example 2 drops to 95.7%, and the antibacterial rate of Comparative Example 3 (without hydrophobic agent) is only 27.6%. This indicates that the two - step preparation process of the present invention effectively avoids the conflict generated by the direct mixing of the hydrophobic agent and the antibacterial agent, ensures the activity of the antibacterial agent, promotes the uniform dispersion of each component, and can still maintain high antibacterial performance even in a complex washing environment, meeting the strict requirements for the hygienic performance of materials in practical applications.

[0051] Example 9 uses amino - siloxane as the hydrophobic agent and activated carbon as the adsorbent, providing data support for exploring the influence of different adsorbents on the material properties. Its initial contact angle is 113.8°, close to those of Example 7 and Example 10 with supercritical foamed polypropylene as the adsorbent, indicating that activated carbon as an adsorbent, although different in structure from supercritical foamed polypropylene, can also effectively load the hydrophobic agent and construct a stable hydrophobic structure. In the boiling water resistance test, the decrease amplitude of hydrophobicity of Example 9 is similar to that of other examples, further proving the effectiveness of activated carbon in maintaining the stability of hydrophobic performance; in terms of antibacterial performance, Example 9 is consistent with other examples, with an antibacterial rate as high as 99.9%. This shows that the selection of different adsorbents does not affect the synergistic effect of the hydrophobic agent and the antibacterial agent in the two - step preparation process, and once again verifies the reliability and adaptability of the process of the present invention.

[0052] Example 10 used a combination of different hydrophobic agents (amino siloxane and long-chain alkyl silane), with an initial contact angle of 114.2°, slightly higher than that of Example 7 and Example 9, showing the possible synergistic effect of the combination of hydrophobic agents and further improving the hydrophobic properties of the material; in the boiling water resistance test, the decrease in hydrophobicity of Example 10 was small under various test conditions. For example, after boiling at 70°C for 1000 h, the contact angle was 113.3°, with a decrease of 1%; after boiling at 100°C with detergent for 168 h, the contact angle was 108.5°, with a decrease of 5%. This indicates that the combination of hydrophobic agents can not only improve the initial hydrophobic properties but also enhance the stability of the hydrophobic structure in complex environments; in terms of antibacterial performance, Example 10 also maintained a high antibacterial rate of 99.9%, indicating that the combination of hydrophobic agents did not have a negative impact on the antibacterial performance of the material. Instead, to a certain extent, due to the better hydrophobic properties, the attachment of bacteria on the material surface was reduced, indirectly enhancing the antibacterial effect.

[0053] In summary, through a comprehensive analysis of Examples 6 - 10 and Comparative Examples 1 - 3, the advantages of the present invention were further verified. The preparation process of the hydrophobic masterbatch, the specific raw material composition, and the two-step method for preparing a fluorine-free hydrophobic modified plastic with antibacterial effects of the present invention had significant effects in improving the hydrophobic properties, antibacterial properties of the material, and ensuring the high efficiency and stability of the production process, and could meet the various performance requirements of the material in practical applications, with broad application prospects.

[0054] The above embodiments only represent several implementation manners of the present invention, which are convenient for understanding the technical solutions of the present invention specifically and in detail, but should not be construed as limiting the scope of the patent protection of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

Claims

1. A hydrophobic masterbatch comprising 20-90 parts of a synthetic resin and 5-40 parts of a hydrophobic agent, characterized in that: Also included is 5-40 parts of an adsorbent.

2. The hydrophobic masterbatch according to claim 1, characterized in that: The synthetic resin is one or a mixture of two or more of homopolypropylene resin, block copolymer polypropylene resin, random copolymer polypropylene resin, polyethylene, polyvinyl chloride, polystyrene, ABS resin and polycarbonate.

3. The hydrophobic masterbatch according to claim 1, characterized in that: The hydrophobic agent is any one of an organic silicon hydrophobic agent, a hydrocarbon hydrophobic agent, and a wax hydrophobic agent, or a mixture of two or more thereof.

4. The hydrophobic masterbatch according to claim 1, characterized in that: The adsorbent is any one of supercritical foamed polypropylene, activated carbon, silica gel, and polyacrylamide, or a mixture of two or more thereof.

5. A method for preparing the hydrophobic masterbatch according to any one of claims 1 to 4, the specific method being: Step 1, adding 5-40 parts of a hydrophobic agent and 5-40 parts of an adsorbent into a low mixing pot and stirring for 2-10 minutes at a stirring rate of 100-200 r / min to obtain an adsorbed hydrophobic agent, and then adding the adsorbed hydrophobic agent and 20-90 parts of a synthetic resin into a high mixing pot and stirring for 2-5 minutes at a stirring rate of 150-300 r / min to obtain a masterbatch; Step 2: adding the masterbatch into a twin-screw extruder for extrusion granulation to obtain the hydrophobic masterbatch.

6. The method for preparing the hydrophobic masterbatch according to claim 5, characterized in that: The processing temperature of the conveying section of the twin-screw extruder is set to 160-170°C, the processing temperature of the compression section is set to 180-190°C, the processing temperature of the homogenization section is set to 170-180°C, the screw speed is set to 400-600r / min, the feeding rate is set to 40-80kg / h, and the aspect ratio of the twin-screw extruder is set to 44-60:

1.

7. A fluorine-free hydrophobic modified plastic with antibacterial effect, characterized in that: Using the hydrophobic masterbatch described in claim 1, the surface contact angle of the fluorine-free hydrophobic modified plastic with antibacterial effect is 113°-115°. After being boiled in water at 70°C for 1000 hours, the contact angle is 109°-113°; after being boiled in water at 100°C for 168 hours, the contact angle is 106°-110°.

8. A method for preparing the fluorine-free hydrophobic modified plastic with antibacterial effect as claimed in claim 7, characterized in that: 10 parts of the hydrophobic masterbatch according to claim 1, 40-95 parts of polypropylene resin, 0.1-3 parts of antibacterial agent, 0.1-1 parts of antioxidant, and 0.1-2 parts of lubricant are added to a high mixing pot and mixed for 3-5 minutes to obtain a mixture, the stirring rate is 150-300r / min, and then the mixture is added to a twin-screw extruder from the main feeding port, the processing temperature of the conveying section is set to 180-190°C, the processing temperature of the compression section is set to 200-210°C, the processing temperature of the homogenizing section is set to 180-190°C, the screw speed is 300-500r / min, and the feeding rate is 50kg / h to obtain the fluorine-free hydrophobic modified plastic with antibacterial effect.

9. The method for preparing the fluorine-free hydrophobic modified plastic with antibacterial effect according to claim 8, characterized in that: In the fluorine-free hydrophobic modified plastic with antibacterial effect prepared by the method, the content of the hydrophobic agent is 0.5-4% based on the mass of the fluorine-free hydrophobic modified plastic with antibacterial effect.

10. An environmental treatment device, characterized in that: It includes the fluorine-free hydrophobic modified plastic with antibacterial effect as described in claim 7.

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