Application of plastic resin polymer particles containing bentonite powder in preparation of lightweight molded products

Abstract

The invention discloses application of plastic resin polymer particles containing bentonite powder in preparation of light molded products, and belongs to the technical field of plastic products. The plastic resin polymer particles are prepared by mixing bentonite-containing powder and plastic resin, can be used for manufacturing light molded products and various environment-friendly molded products, and also have the antibacterial characteristic; the raw material has a specific gravity difference and is suitable for various products.

Description

Technical Field

[0001] This invention belongs to the field of plastic products technology, specifically relating to the application of plastic resin polymer particles containing bentonite powder in the preparation of lightweight molded products. Background Technology

[0002] Polypropylene (PP) resin is widely used in various molded products, such as injection-molded products in the form of sheets, containers, caps (valves), etc., and hollow molded products such as films and air ducts. In addition, films are also widely used in packaging materials for food and textile products due to their mechanical, optical, and thermal properties.

[0003] Generally speaking, polypropylene (PP) resin is inexpensive, lightweight, and strong, making it widely used in daily life. However, these containers only offer the advantages of being lightweight and strong, lacking other additional functions or effects. While traditional PP resin products possess the core advantages of being lightweight and strong, their functions are relatively limited, lacking additional properties such as antibacterial and reinforcing properties, making it difficult to meet the modern society's demand for multifunctional materials.

[0004] On the other hand, pure bentonite, as an industrial mineral with rich physicochemical properties, not only possesses cation exchange capacity, binding properties, swelling properties, and adsorption properties, but also has natural antibacterial properties. It has been applied in various fields such as casting, textiles, papermaking, detergents, and animal feed, and market demand continues to expand. In recent years, relying on its natural layered structure, the application potential of bentonite in functional composite materials and polymer materials has been further explored, and it is gradually becoming an important direction for the research and development of high-value-added new materials.

[0005] Against this backdrop, how to combine the basic advantages of polypropylene (PP) resin with the functional characteristics of bentonite to develop a new composite material that is lightweight, has improved impact strength, and antibacterial properties has become an important issue that needs to be explored in the field of materials. This is of great significance for expanding the application range of plastic materials and enhancing their functional value. Summary of the Invention

[0006] The purpose of this invention is to provide an application of plastic resin polymer particles containing bentonite powder in the preparation of lightweight molded products. These plastic resin polymer particles are prepared by mixing plastic resin with bentonite powder. They can not only be used to make lightweight molded products, but also various environmentally friendly molded products, and have antibacterial properties. The raw material has a low specific gravity and is suitable for a wide range of products.

[0007] This invention is achieved through the following technical solution:

[0008] The application of a plastic resin polymer particle containing bentonite powder in the preparation of lightweight molded articles, wherein the plastic resin polymer particle is composed of 30-40% bentonite powder and 60-70% plastic resin.

[0009] Preferably, the method for preparing the plastic resin polymer particles includes:

[0010] The dried plastic resin granules and bentonite powder sprayed with additives are added to a high-speed mixer in proportion and mixed until the material is evenly dispersed. Then, antioxidants, antibacterial agents and jade powder are added and mixed evenly. The mixture is then heated to 200-290℃ in an extruder for melt blending and plasticizing to form granules. The granules are then dried in a dryer at 75-85℃ to obtain the finished granules.

[0011] Preferably, the additive is a silane coupling agent or a maleic anhydride graft polymer.

[0012] The amount of the additive added is 1-3% of the mass of the bentonite powder;

[0013] The antibacterial agent is silver nanoparticles;

[0014] The amount of antioxidant added is 3-7% of the mass of plastic resin, the amount of silver nanoparticles added is 5-20% of the total mass of bentonite powder, and the amount of jade powder added is 1-10% of the total mass of bentonite powder.

[0015] Preferably, the bentonite powder has a particle size of 150-320 mesh;

[0016] The moisture content of the bentonite powder is not higher than 7%;

[0017] The antibacterial agent has a particle size of 5-10 nm and a purity of 99.9%.

[0018] Preferably, the bentonite powder has a particle size of 230-300 mesh;

[0019] The moisture content of the bentonite powder is no higher than 4%.

[0020] Preferably, the bentonite powder is obtained by crushing the raw ore, mixing the crushed raw ore with water at a mass ratio of 1:1 to 5 and stirring at 100 to 1000 rpm for 30 to 60 minutes to remove impurities, separating the raw ore into solid and liquid components, and then recovering the bentonite powder by filtering, dehydrating, and drying the separated liquid slurry.

[0021] Preferably, the drying temperature is 100-150°C and the drying time is 1-6 hours.

[0022] Preferably, the melt flow index of the plastic resin is 0.5 to 80 g / 10 min.

[0023] Preferably, the plastic resin is a plastic monomer polymer.

[0024] Preferably, the plastic monomer polymer is polypropylene (PP) resin;

[0025] The polypropylene (PP) resin is one or more of propylene random copolymer and propylene-ethylene block copolymer.

[0026] Compared with the prior art, the present invention has at least the following technical effects:

[0027] This invention provides an application of plastic resin polymer particles containing bentonite powder in the preparation of lightweight molded products. These plastic resin polymer particles are prepared by mixing plastic resin with bentonite powder. They can not only be used to make lightweight molded products, but also various environmentally friendly molded products, and have antibacterial properties. The raw material has a low specific gravity and is suitable for a wide range of products. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of polymer particles;

[0029] Figure 2 The molded product prepared using Example 1. Detailed Implementation

[0030] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0031] One specific embodiment of the present invention is as follows:

[0032] Bentonite powder has the chemical composition (Al,Mg)₂Si₄O₁₀(OH)₂·4H₂O, and is a layered clay mineral. Its hardness is 1-1.5, specific gravity is 2-2.5, and refractive index is 1.48-1.6. It is mostly white, gray, or light red, sometimes with a bluish or green tint, and has no luster. It is formed from aluminum-rich minerals or rocks through metamorphism, belonging to the clay mineral class and containing clay components. Bentonite powder possesses many unique properties: it can absorb water and swell to 7-10 times its original volume, exhibiting high ion exchange capacity; as clay, it generates adhesion at a water content of 150%, loses adhesion at around 500% water content, and has low internal friction resistance.

[0033] Plastic resin polymer granules, with plastic resin as the base resin, wherein the plastic resin can be one or more of plastic monomer polymers, propylene random copolymers, and propylene-ethylene block copolymers. The melt index (MI, test standard ASTM D 1238, 230℃, 2.16kg) of the plastic resin is preferably 0.5–80 g / 10 min, more preferably 5–60 g / 10 min. If the melt index is less than 0.5 g / 10 min, the processability will decrease due to the increased melt viscosity after mixing with bentonite powder; if it exceeds 80 g / 10 min, the impact performance of molded products made from the polymer granules will decrease. Therefore, the above range is more suitable.

[0034] Furthermore, if polypropylene (PP) is selected as the plastic resin, its density should preferably be less than 0.95 g / cm³, its melting point should exceed 90°C, and preferably its density should be less than 0.9 g / cm³. 3 More preferably less than 0.85 g / cm³ 3 With these properties, the melting point can be further improved. Furthermore, the polypropylene used is prepared by a metallocene catalyst, which can be a Thalosen catalyst or a completely asymmetric ANSA metallocene catalyst, preferably a symmetric ANSA metallocene catalyst. These metallocene catalysts, composed of specific ligands, exhibit high catalytic activity and stereoregularity.

[0035] The plastic resin polymer particles containing bentonite powder in this technical solution are composed of 60-70% plastic resin and 30-40% bentonite powder. When the plastic resin content is less than 60%, the resin polymer particles will exhibit cloudy color and decreased mechanical properties; when the plastic resin content exceeds 70%, the relative content of bentonite powder decreases, which will lead to the failure to achieve the expected effects such as antibacterial properties. Therefore, the above-mentioned ratio range is more reasonable.

[0036] Taking polypropylene resin as an example, drying is required, which can be done at a temperature of 75-85℃ for 1-3 hours. The particle size of bentonite powder should preferably be 150-320 mesh, preferably 230-300 mesh. If the particle size exceeds this range, problems such as poor dispersion or wear on the screw inside the equipment during molding may occur. Its moisture content should be less than 7%, preferably less than 4%. When the moisture content exceeds 7%, the smoothness of bentonite will reduce the performance of the resin polymer particles, resulting in decreased processability during molding. If it exceeds 14%, molding will be impossible. Therefore, it is preferable to dry the bentonite powder. Drying can be carried out in a dryer or dehumidifier, preferably at a temperature of 100-150℃ for 1-6 hours. It is best to dry the bentonite powder and plastic resin separately; if they are mixed and then dried, the drying efficiency will be low.

[0037] Bentonite powder can be prepared by a wet process, and the specific steps are as follows:

[0038] Crushing raw ore: Using a crusher to crush the raw bentonite ore.

[0039] Mixing and stirring: Mix the crushed raw ore with water at a ratio of 1:1-5, and then stir in a mixer at a speed of 100-1000 rpm for 30-60 minutes. If protrusions are installed on the inner wall of the mixing tank, the impact energy of the protrusions during stirring and rotation can, to a certain extent, separate impurity minerals from the raw ore.

[0040] Impurity removal: Impurities are removed from the stirred raw ore using a classifier.

[0041] Separation and recovery: Centrifuges and classifiers are used to process the slurry after removing impurities, separating the solid and slurry, and recovering the bentonite.

[0042] Drying and powdering: The recovered bentonite is dried in a dryer at a temperature of 100-150℃ for 1-6 hours to obtain bentonite powder.

[0043] The plastic resin polymer particles containing bentonite powder in this application may also contain antioxidants to prevent aging of the finished product. Based on 100% plastic resin content, the amount of antioxidant added is 1-10%, preferably 3-7%. When the antioxidant content is less than 1%, the effect is negligible; when it exceeds 10%, processability problems will occur, so the above range is more suitable.

[0044] The preparation method of the plastic polymer particles containing bentonite powder is as follows: 60-70% of plastic resin and 30-40% of bentonite powder are mixed, heated to 200-290℃ for melt blending and plasticizing to form particles, and then the particles are dried in a dryer at 75-85℃.

[0045] The plastic resin polymer granules containing bentonite powder can also be coated with silver (Ag) nanoparticles to enhance the antibacterial properties of the molded products. The silver nanoparticles can be applied to the surface of the bentonite powder. The amount of silver nanoparticles added relative to 100% bentonite powder content is 5-20%. If the content is below 5%, the enhanced antibacterial effect cannot be observed; if it exceeds 20%, although the antibacterial effect may be improved, it will lead to reduced processability. Therefore, the above range is ideal. The purity of the silver nanoparticles is 99.9%, the particle size is 5-10 nm, and the coating operation is performed after the bentonite powder is dried to prevent the side effect of the bentonite powder absorbing moisture. Since the melting point of silver is 961℃, even if the bentonite powder surface is coated with silver, the coating can be maintained during injection or extrusion. The coating method can be vacuum deposition, spraying, etc., and is not limited to these methods.

[0046] The plastic resin polymer granules containing bentonite powder can also have jade powder added to enhance their antibacterial, deodorizing, and detoxifying effects. Based on a 100% bentonite powder content, the amount of jade powder added is 1-10%. When the jade powder content is below 1%, the antibacterial, deodorizing, and detoxifying effects are negligible; when it exceeds 10%, although the above effects may be improved, it will lead to reduced processability, so the above range is more suitable.

[0047] Example 1:

[0048] The application of a plastic resin polymer particle containing bentonite powder in the preparation of lightweight molded articles, wherein the plastic resin polymer particle is composed of 35% bentonite powder and 65% plastic resin.

[0049] The method for preparing the plastic resin polymer particles includes:

[0050] The dried plastic resin granules and bentonite powder sprayed with additives are added to a high-speed mixer in proportion and mixed until the material is evenly dispersed. Then, antioxidants and jade powder are added and mixed evenly. The mixture is then heated to 260°C in an extruder for melt blending and plasticizing to form granules. The granules are then dried in a dryer at 80°C to obtain the finished granules.

[0051] The auxiliary agent is a silane coupling agent or a maleic anhydride grafted polymer.

[0052] The amount of the additive added is 3% of the mass of the bentonite powder;

[0053] The amount of antioxidant added is 3% of the mass of the plastic resin and the amount of jade powder added is 4% of the total mass of the bentonite powder.

[0054] The bentonite powder has a particle size of 150 mesh;

[0055] The moisture content of the bentonite powder is no higher than 7%.

[0056] The bentonite powder has a particle size of 230 mesh;

[0057] The moisture content of the bentonite powder is no higher than 4%.

[0058] The bentonite powder is obtained by crushing the raw ore, mixing the crushed raw ore with water at a mass ratio of 1:2 and stirring at 400 rpm for 40 minutes to remove impurities, separating the raw ore into solid and liquid, and then recovering the bentonite powder by filtering, dehydrating, and drying the separated liquid slurry.

[0059] The drying temperature is 130℃ and the drying time is 2 hours.

[0060] The melt flow index of the plastic resin is 10 g / 10 min.

[0061] The plastic resin is a polymer of plastic monomers.

[0062] The plastic monomer polymer is polypropylene (PP) resin;

[0063] The polypropylene (PP) resin is a random copolymer of propylene.

[0064] Example 2:

[0065] The application of a plastic resin polymer particle containing bentonite powder in the preparation of lightweight molded articles, wherein the plastic resin polymer particle is composed of 35% bentonite powder and 65% plastic resin.

[0066] The method for preparing the plastic resin polymer particles includes:

[0067] The dried plastic resin granules and bentonite powder sprayed with additives are added to a high-speed mixer in proportion and mixed until the material is evenly dispersed. Then, antioxidants, antibacterial agents and jade powder are added and mixed evenly. The mixture is then heated to 260°C in an extruder for melt blending and plasticizing to form granules. The granules are then dried in a dryer at 80°C to obtain the finished granules.

[0068] The auxiliary agent is a silane coupling agent or a maleic anhydride grafted polymer.

[0069] The amount of the additive added is 3% of the mass of the bentonite powder;

[0070] The antibacterial agent is silver nanoparticles;

[0071] The antioxidant is added at 3% of the mass of the plastic resin, the silver nanoparticles at 10% of the total mass of the bentonite powder, and the jade powder at 4% of the total mass of the bentonite powder.

[0072] The bentonite powder has a particle size of 150 mesh;

[0073] The moisture content of the bentonite powder is not higher than 7%;

[0074] The antibacterial agent has a particle size of 10 nm and a purity of 99.9%.

[0075] The bentonite powder has a particle size of 230 mesh;

[0076] The moisture content of the bentonite powder is no higher than 4%.

[0077] The bentonite powder is obtained by crushing the raw ore, mixing the crushed raw ore with water at a mass ratio of 1:2 and stirring at 400 rpm for 40 minutes to remove impurities, separating the raw ore into solid and liquid, and then recovering the bentonite powder by filtering, dehydrating, and drying the separated liquid slurry.

[0078] The drying temperature is 130℃ and the drying time is 2 hours.

[0079] The melt flow index of the plastic resin is 10 g / 10 min.

[0080] The plastic resin is a polymer of plastic monomers.

[0081] The plastic monomer polymer is polypropylene (PP) resin.

[0082] Comparative Example 1:

[0083] Polypropylene (PP) resin was selected, with a melt flow index of 5–60 g / 10 min, and the test standard was ASTM D 1238, 230℃, 2.16 kg. The resin granules were dried in a desiccator at 75–85℃ for 1–3 hours to remove any trace amounts of moisture that might have been adsorbed on the surface, thus preventing defects such as bubbles and holes in the container caused by moisture during the molding process.

[0084] Select an injection molding machine of appropriate specifications. Install a matching mold according to the size and shape of the disposable container. The mold must be cleaned beforehand, and the polypropylene (PP) mold is typically preheated to 40-60℃. Barrel temperature: Set according to the melting characteristics of the plastic resin. The barrel temperature for polypropylene (PP) is generally 180-220℃ (feeding section 180-190℃, compression section 190-210℃, nozzle section 200-220℃) to ensure the resin melts fully and does not degrade. Injection pressure: Adjust according to the structural complexity of the container, typically 50-100MPa, to ensure the molten resin fills the mold cavity smoothly. Holding pressure and time: The holding pressure is generally 50-70% of the injection pressure, and the holding time is 5-30 seconds to prevent backflow of molten material in the cavity and ensure dimensional stability of the container. Cooling time: Set according to the container wall thickness, typically 10-60 seconds, to allow the container to cool and solidify fully within the mold, preventing deformation after demolding.

[0085] Injection molding: Dry pure plastic resin granules are added to the hopper of the injection molding machine. The resin is heated and melted in the barrel into a viscous flow state. It is then pushed by the screw and injected into the closed mold cavity through the nozzle. The pressure is maintained and cooled under the set pressure and temperature. After the container is completely shaped, the mold is opened and the disposable container is taken out through the ejection mechanism.

[0086] Experimental Example: Comparison of Antibacterial Properties

[0087] 1. To verify the antibacterial properties of molded products prepared from plastic resin polymer particles composed of 30-40% bentonite powder and 60-70% plastic resin, to clarify the influence of different additives (such as silver nanoparticles) on the antibacterial effect, and to provide data support for the application of these particles in lightweight antibacterial molded products.

[0088] 2. Experimental Materials and Equipment

[0089] Samples: Example 1 product (a disposable container made of plastic resin polymer particles containing 30-40% bentonite powder), Example 2 product (a disposable container made of plastic resin polymer particles containing 30-40% bentonite powder coated with silver nanoparticles), and Comparative Example 1 product (a disposable container made of pure plastic resin).

[0090] Strains: Staphylococcus aureus (ATCC 6538, strain 1), Escherichia coli (ATCC 25922, strain 2).

[0091] Culture media: Nutrient agar medium, nutrient broth medium.

[0092] Equipment: Clean bench, constant temperature incubator (temperature controllable at 35±1℃, relative humidity 90%), colony counter, pipette, petri dishes, test tubes, etc.

[0093] 3. Experimental Procedure

[0094] Preparation of bacterial culture: Strain 1 and strain 2 were inoculated separately into nutrient broth medium and cultured at 35±1℃ for 18–24 hours. Then, they were diluted with sterile physiological saline to adjust to the specified initial concentration (strain 1: 1.2 × 10⁻⁶). 5 cells / ml; strain 2: 1.6×10 5 (cells / ml).

[0095] Sample inoculation: In a clean bench, take 0.1 ml of the prepared bacterial solution and inoculate it evenly on the surface of the product of Example 1, the product of Example 2 and the product of Comparative Example 1.

[0096] Culture: Place the inoculated samples in a constant temperature incubator at 35±1℃ and 90% relative humidity for 24 hours.

[0097] Viable cell count: After incubation, rinse the sample surface with sterile physiological saline and collect the rinsing solution. Serially dilute the rinsing solution, and spread 0.1 ml of the appropriately diluted solution onto nutrient agar plates. Incubate at 35±1℃ for 24–48 hours, then count the colonies using a colony counter to calculate the number of viable cells per milliliter of rinsing solution.

[0098] 4. Evaluation Indicators

[0099] The number of surviving bacteria (cells / mL) on the sample surface after 24 hours was used as an indicator to evaluate antibacterial performance. The fewer the number of surviving bacteria, the better the antibacterial effect.

[0100] 5. Conclusion: The antimicrobial properties of the disposable containers manufactured according to Examples 1 / 2 and Comparative Example 1 were tested, as shown in Table 1 below.

[0101] Evaluation method: using the specified initial concentration (strain 1: 1.2 × 10⁻⁶). 5 cells / ml; strain 2: 1.6×10 5 After inoculating bacteria at a concentration of cells / ml and culturing at 35±1℃ and RH 90% for 24 hours, the survival rate was evaluated by measuring the number of viable bacteria.

[0102] Table 1

[0103]

[0104]

[0105] As can be seen from the experimental results in Table 1 above, Examples 1 and 2, containing bentonite powder, showed a significant reduction in bacterial count after 24 hours compared to Comparative Example 1, where bacteria multiplied naturally, demonstrating excellent antibacterial effects. In particular, Example 2, containing bentonite powder coated with silver (Ag), showed even better antibacterial effects. This indicates that silver (Ag) particles can inhibit the growth and reproduction of bacteria and fungi, eliminate odors, and possess good hygienic properties.

[0106] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. The application of plastic resin polymer particles containing bentonite powder in the preparation of lightweight molded articles, characterized in that, The plastic resin polymer particles are composed of 30-40% bentonite powder and 60-70% plastic resin.

2. The application of the plastic resin polymer particles containing bentonite powder according to claim 1 in the preparation of lightweight molded articles, characterized in that, The method for preparing the plastic resin polymer particles includes: The dried plastic resin granules and bentonite powder sprayed with additives are added to a high-speed mixer in proportion and mixed until the material is evenly dispersed. Then, antioxidants, antibacterial agents and jade powder are added and mixed evenly. The mixture is then heated to 200-290℃ in an extruder for melt blending and plasticizing to form granules. The granules are then dried in a dryer at 75-85℃ to obtain the finished granules.

3. The application of plastic resin polymer particles containing bentonite powder according to claim 2 in the preparation of lightweight molded articles, characterized in that, The auxiliary agent is a silane coupling agent or a maleic anhydride grafted polymer. The amount of the additive added is 1-3% of the mass of the bentonite powder; The antibacterial agent is silver nanoparticles; The amount of antioxidant added is 3-7% of the mass of plastic resin, the amount of silver nanoparticles added is 5-20% of the total mass of bentonite powder, and the amount of jade powder added is 1-10% of the total mass of bentonite powder.

4. The application of the plastic resin polymer particles containing bentonite powder according to claim 2 in the preparation of lightweight molded articles, characterized in that, The bentonite powder has a particle size of 150-320 mesh; The moisture content of the bentonite powder is not higher than 7%; The antibacterial agent has a particle size of 5-10 nm and a purity of 99.9%.

5. The application of the plastic resin polymer particles containing bentonite powder according to claim 4 in the preparation of lightweight molded articles, characterized in that, The bentonite powder has a particle size of 230-300 mesh; The moisture content of the bentonite powder is no higher than 4%.

6. The application of the plastic resin polymer particles containing bentonite powder according to claim 2 in the preparation of lightweight molded articles, characterized in that, The bentonite powder is obtained by crushing the raw ore, mixing the crushed raw ore with water at a mass ratio of 1:1 to 5, stirring at 100 to 1000 rpm for 30 to 60 minutes to remove impurities, separating the raw ore into solid and liquid components, and recovering the bentonite powder by filtering, dehydrating, and drying the separated liquid slurry.

7. The application of the plastic resin polymer particles containing bentonite powder according to claim 6 in the preparation of lightweight molded articles, characterized in that, The drying temperature is 100-150℃, and the drying time is 1-6 hours.

8. The application of the plastic resin polymer particles containing bentonite powder according to claim 2 in the preparation of lightweight molded articles, characterized in that, The melt flow index of the plastic resin is 0.5 to 80 g / 10 min.

9. The application of the plastic resin polymer particles containing bentonite powder according to claim 8 in the preparation of lightweight molded articles, characterized in that, The plastic resin is a polymer of plastic monomers.

10. The application of the plastic resin polymer particles containing bentonite powder according to claim 9 in the preparation of lightweight molded articles, characterized in that, The plastic monomer polymer is polypropylene (PP) resin; The polypropylene (PP) resin is one or more of propylene random copolymer and propylene-ethylene block copolymer.

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