Preparation method of plastic particles with far infrared and zinc ion antibacterial function and functional plastic

Abstract

This invention discloses a method for preparing plastic granules with far-infrared and zinc ion antibacterial functions and a functional plastic, belonging to the field of polymer materials technology. The method includes: heating a thermoplastic composite material to a molten state, extruding it into a strip-shaped melt using an extrusion device, introducing the strip-shaped melt into a cooling water tank for cooling, and placing far-infrared liquid material and antibacterial zinc ion solution in the cooling water tank. During the transition of the strip-shaped melt from a molten state to a solid state, instantaneous free volume or microporous structure is formed. The far-infrared liquid material and liquid antibacterial zinc ions penetrate and fill the interior of the strip-shaped melt through capillary action, pressure difference, or diffusion mechanisms. The mixture is then cooled, dried, and pelletized to obtain plastic granules with far-infrared and zinc ion antibacterial functions. This invention achieves good dispersion and long-lasting far-infrared and antibacterial functions without adding far-infrared powder or zinc oxide powder during the melt mixing stage, and has the advantages of simplified process and stable performance.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a method for preparing plastic particles with far-infrared and zinc ion antibacterial functions and functional plastics. Background Technology

[0002] In the prior art, methods for giving plastic materials far-infrared function and antibacterial effect mainly include: 1) directly mixing far-infrared powder and antibacterial powder into plastic for melt mixing; 2) preparing far-infrared masterbatch and then mixing it with antibacterial and other substrates; 3) coating far-infrared materials and antibacterial agents onto the surface of plastic.

[0003] However, the above-mentioned methods for preparing plastic granules generally have the following drawbacks: 1) the powder is prone to agglomeration during melt mixing, resulting in uneven dispersion; 2) excessive addition will affect mechanical strength and processability; 3) the process is complex and costly; 4) the surface coating method lacks durability and its effectiveness will decline. Furthermore, in the cooling process of plastic water-jet strips, molten plastic forms instantaneous micropores or free volume structures when rapidly entering cooling water at high temperatures, but this structure has not yet been effectively utilized in existing technologies. Summary of the Invention

[0004] The main objective of this invention is to provide a method for preparing plastic granules with far-infrared and zinc ion antibacterial functions. By utilizing the porous structure formed during the cooling process of the plastic strip, far-infrared liquid materials and water-based antibacterial zinc ions are allowed to penetrate and fill the interior of the plastic, thereby obtaining plastic granules with far-infrared and zinc ion antibacterial functions.

[0005] Another object of the present invention is to provide a functional plastic, which is prepared by the method for preparing plastic particles with far-infrared and zinc ion antibacterial functions, wherein far-infrared and zinc ion antibacterial materials are introduced by pore filling during the cooling process of melt-extruded plastic strips.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing plastic granules with far-infrared and zinc ion antibacterial functions, comprising the following steps:

[0008] S1. Melt extrusion: The thermoplastic composite material is heated to a flowable molten state and extruded through an extrusion device to form a strip-shaped melt, wherein the temperature of the strip-shaped melt is higher than its glass transition temperature or crystallization initiation temperature;

[0009] S2. Preparation of liquid functional materials: Disperse far-infrared liquid materials and zinc ion solution in a liquid medium to form an aqueous solution, and add it to the cooling water tank;

[0010] S3. Cooling of Plastic Strips: The strip-shaped melt is introduced into a cooling water tank, comes into contact with the cooling medium, and is rapidly cooled to form a plastic strip; the rapid cooling process includes a temperature gradient from the outer layer to the inside; the strip-shaped melt changes from a molten state to a solid state, forming an instantaneous free volume or microporous structure before it is fully crystallized or solidified; the far-infrared liquid material and zinc ions enter this instantaneous free volume or microporous structure through capillary permeation, pressure difference drive, or diffusion to complete pore filling and are fixed inside the plastic;

[0011] S4. Drying and pelletizing: After cooling, the plastic strips are air-dried or hot-air-dried and pelletized to obtain plastic granules with far-infrared and zinc ion antibacterial functions.

[0012] Preferably, in step S1, the thermoplastic composite material includes a matrix resin and a functional masterbatch. The matrix resin is selected from one or more combinations of polyethylene (PE), polypropylene (PP), polystyrene (PS), acrylonitrile-butadiene-styrene copolymer (ABS), and polyethylene terephthalate (PET). The functional masterbatch includes at least one of color masterbatch for plastic coloring, filler masterbatch, antioxidant masterbatch, UV resistant masterbatch, antistatic masterbatch, flame retardant masterbatch, antibacterial masterbatch, open-cell masterbatch, foaming masterbatch, and reinforcing masterbatch.

[0013] Preferably, in step S2, the far-infrared liquid material is an aqueous liquid material with far-infrared radiation properties, comprising microscopic particles of nano-metal oxides and / or micron-sized inorganic oxides. The nano-metal oxides are selected from at least one of titanium dioxide, aluminum oxide, iron oxide, manganese oxide, magnesium oxide, and calcium oxide, with a particle size of 10-50 nm. The micron-sized inorganic oxides are inorganic oxides with far-infrared radiation properties in the 5-14 micron wavelength band, more preferably silicon dioxide. This wavelength band corresponds to the main thermal radiation range of biological surfaces, allowing the inorganic oxides to continuously absorb and re-emit far-infrared radiation under low-energy conditions and stably embed themselves within the internal pore structure of the plastic particles. The far-infrared radiation properties and dispersion stability in the liquid medium are enhanced by the microscopic particles of the nano-metal oxides and / or micron-sized inorganic oxides.

[0014] Preferably, in step S2, the zinc ion solution is an aqueous solution of zinc oxide.

[0015] Preferably, in step S2, the far-infrared liquid material and zinc ions exist in the cooling medium in the form of a liquid dispersion. The far-infrared liquid material maintains a stable dispersion state during the cooling process, continuously providing permeable active particles within the time window during which the plastic strip changes from a molten state to a solid state, allowing them to enter and fill the instantaneous free volume or microporous structure inside the plastic strip.

[0016] Preferably, in step S2, the cooling water tank further includes a dispersing agent selected from dispersants, surfactants, or combinations thereof, which is used to improve the dispersibility of the far-infrared liquid material in the cooling medium and its wettability on the surface of the plastic strip, so that the far-infrared liquid material and zinc ions can effectively penetrate into the instantaneous free volume or microporous structure of the plastic strip before it is completely cured.

[0017] Preferably, in step S3, the temperature of the cooling water tank is 30-60℃, more preferably 35-45℃, so that during the process of the plastic strip changing from a molten state to a solid state, the sealing effect formed by the rapid solidification of its surface is delayed, and the internal free volume or microporous structure is kept in an open state within a predetermined time interval, thereby improving the depth and uniformity of the far-infrared liquid material entering the internal structure through capillary penetration and diffusion.

[0018] Preferably, in step S3, the cooling rate of the strip-shaped melt is 1-50°C / sec, which controls the crystallization kinetics of the transition from the molten state to the solid state and affects the formation and duration of the internal microporous structure.

[0019] Preferably, in step S3, the plastic strip stays in the cooling water tank for 0.5-30 seconds, allowing the far-infrared liquid material and zinc ions to penetrate and fill the internal structure within this time window.

[0020] Preferably, in step S3, the traction speed of the plastic strip is 1-150 m / min, adjusting the heat exchange efficiency and porosity of the plastic strip in the cooling medium.

[0021] The temperature, cooling rate, residence time, and traction speed of the cooling water tank are controlled in a coordinated manner to form a time window for the far-infrared liquid material to penetrate, allowing the material to enter and be fixed in the micropores or free volume structure inside the plastic strip.

[0022] In a second aspect, the present invention provides a functional plastic, which is prepared by the method for preparing plastic particles with far-infrared and zinc ion antibacterial functions. The plastic particle contains micropores or free volume structures formed by the transformation of molten plastic from a non-equilibrium state structure during the cooling process of the plastic strip. Far-infrared materials and antibacterial zinc ions are distributed in the micropores or free volume structures. The far-infrared materials and antibacterial zinc ions penetrate into and are fixed in the structure within the time window during which the plastic changes from a molten state to a solid state. They are embedded in the plastic particles rather than attached to the surface.

[0023] Compared to traditional techniques of directly mixing or surface coating far-infrared powders onto plastic materials, this invention has at least the following technical advantages:

[0024] 1. Improve the uniformity of material dispersion. This invention utilizes the instantaneous pores formed during the cooling process of the plastic strip to allow far-infrared liquid material and water-based antibacterial zinc ions to penetrate into the plastic and complete the filling. Compared with traditional powder mixing methods, this can effectively avoid particle agglomeration and ensure that the far-infrared material and antibacterial zinc ions are uniformly distributed inside the plastic.

[0025] 2. Reduced processing complexity and energy consumption. This invention eliminates the need to add far-infrared and zinc oxide powders during the high-temperature melting and mixing stage, and also eliminates the need for additional mixing equipment or high-shear dispersion processes. Material introduction can be completed directly using existing plastic strip cooling processes, which helps reduce process complexity and energy consumption.

[0026] 3. Reduce negative impact on mechanical properties. Traditional high-filler powders can easily cause a decrease in the ductility or strength of plastic materials. However, this invention fills the pores during the cooling stage, and the far-infrared materials and antibacterial materials are mainly distributed in the internal microstructure, which has a smaller impact on the overall mechanical properties of the substrate.

[0027] 4. Enhanced stability and durability of far-infrared function and antibacterial effect. The far-infrared material and antibacterial zinc ions of this invention are embedded inside the plastic particles rather than just attached to the surface, making them less prone to loss during subsequent processing or use, thus maintaining a longer-lasting far-infrared radiation effect and continuous antibacterial effect.

[0028] 5. Improved material utilization efficiency. This invention introduces far-infrared materials and antibacterial zinc ions through a permeation-filling method, achieving the desired functional effect with a lower addition amount, without requiring any additional processing steps. Compared to traditional high-proportion filling methods, this helps reduce material usage and costs.

[0029] 6. High process compatibility and easy industrial application. This invention can be directly integrated into existing plastic strip granulation equipment without significant modifications to the equipment structure or changes to the manufacturing process, thus possessing high industrial application value. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the plastic granule melt extrusion equipment with far-infrared and zinc ion antibacterial functions in the embodiment.

[0031] Figure 2 This is a schematic diagram of the pore development and infiltration filling process of the hot-extruded (melt-extruded) plastic strip in the embodiment.

[0032] Figure 3 This is a schematic diagram of the pore formation and filling process during the cooling of the plastic water strip in the embodiment.

[0033] Figure 4 This is a schematic diagram of the pore formation and filling process during the cooling of the plastic water strip in the embodiment.

[0034] Figure 5 This is a schematic diagram of the internal structure of the plastic particles with far-infrared and zinc ion antibacterial functions in the embodiment.

[0035] Figure 6 This is a schematic diagram comparing the structures of plastic granules with far-infrared and zinc ion antibacterial functions and traditionally compounded plastic granules in the embodiments. Detailed Implementation

[0036] To more fully understand and demonstrate the technical solutions, objectives, and advantages of the present invention, the technical effects produced by the present invention will be further described in detail and completely below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be noted that other embodiments obtained by those skilled in the art without departing from the concept of the present invention are all within the protection scope of the present invention.

[0037] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0038] The following embodiments illustrate the structure of a plastic granule melt extrusion device with far-infrared and zinc ion antibacterial functions, as shown in the example. Figure 1 As shown, a method for preparing plastic granules with far-infrared and zinc ion antibacterial functions is proposed, including the following steps:

[0039] S1, Melt Extrusion

[0040] Thermoplastic composite materials, including color masterbatches for plastic coloring, low-cost and modified filler masterbatches, functional masterbatches (antioxidant, anti-UV, antistatic, flame retardant, antibacterial, open-cell, foaming, etc. masterbatches), reinforcing masterbatches, and carrier resins such as PE, PP, PS, ABS, PET, etc., are heated to above their melting temperature to form a flowable molten state. The molten material is then extruded from a die through an extrusion device to form a strip-shaped melt, wherein the temperature of the melt is higher than its glass transition temperature or crystallization initiation temperature.

[0041] S2, Formulation of liquid functional materials

[0042] An aqueous solution is formed by dispersing a water-based liquid material with far-infrared radiation properties and a zinc ion solution in a liquid medium and then adding it to a cooling water tank.

[0043] S3, Plastic strip cooling

[0044] The strip-shaped melt is introduced into a cooling water tank, where it comes into contact with the cooling medium and is rapidly cooled to form a plastic strip structure. This cooling process includes a temperature gradient from the outer layer to the inside.

[0045] S4, Pore filling

[0046] After entering the cooling water tank, the strip-shaped melt transforms from a molten state to a solid state. During the time interval before complete crystallization or solidification, a transient free volume or microporous structure forms within it. Far-infrared liquid material and antibacterial zinc ions enter this transient free volume or microporous structure through capillary permeation, pressure difference, or diffusion, completing the filling and fixing it inside the plastic. Figure 2-4 As shown.

[0047] S5. Drying and fixing

[0048] After cooling, the plastic strips are air-dried or hot-dried to remove moisture from the liquid medium and fix it into the pores of the plastic strips.

[0049] S6, granulation

[0050] The dried plastic strips are cut into pellets to form plastic granules with far-infrared and antibacterial properties. Their internal structure is as follows: Figure 5 As shown.

[0051] Example 1

[0052] Substrate: Linear low-density polyethylene (LLDPE);

[0053] Far-infrared liquid material: A nanoporous material solution was prepared using the method disclosed in patent document CN103316602B and used as a far-infrared liquid material;

[0054] Antibacterial zinc ion aqueous solution;

[0055] Liquid medium: water;

[0056] Addition ratio: 30% far-infrared aqueous solution and 800 ppm zinc ions, 70% water;

[0057] Far-infrared liquid materials and zinc ion aqueous solutions are dispersed in water to form a suspension, which is then added to a cooling water tank. During cooling, the suspension penetrates into the pores of plastic strips. After drying and pelletizing, plastic granules with far-infrared and antibacterial properties are obtained. The structure of these granules is compared with that of plastic granules prepared by traditional mixing methods. Figure 6 As shown.

[0058] Example 2

[0059] Based on Example 1, a surfactant is further added to the far-infrared liquid material. The surfactant is selected from one or a combination of anionic, cationic or nonionic surfactants to reduce the surface tension of the liquid medium and improve the wettability of the plastic material, so that the far-infrared liquid material can penetrate into the transient pores or free volume structure of the plastic strip more effectively before the plastic strip is completely cured.

[0060] Example 3

[0061] Based on Example 1, the temperature of the cooling water tank is controlled within 30-60℃, preferably 35-45℃, so that during the transition of the plastic strip from molten to solid state, the sealing effect formed by the rapid solidification of its surface is delayed, and the internal free volume or microporous structure is kept in an open state within a predetermined time range, thereby improving the depth and uniformity of the far-infrared liquid material entering the internal structure through capillary penetration and diffusion.

[0062] Examples 4-7

[0063] Based on Example 1, Examples 4-7 can achieve the same effect by modifying the plastic substrate to PP, PS, ABS, and PET, respectively.

[0064] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing plastic granules with far-infrared and zinc ion antibacterial functions, characterized in that, Includes the following steps: S1. Melt extrusion: The thermoplastic composite material is heated to a flowable molten state and extruded through an extrusion device to form a strip-shaped melt. The temperature of the strip-shaped melt is higher than its glass transition temperature or crystallization initiation temperature. S2. Preparation of liquid functional materials: Disperse far-infrared liquid materials and zinc ion solution in a liquid medium to form an aqueous solution, and add it to the cooling water tank; S3. Cooling of the plastic strip: The strip-shaped melt is introduced into a cooling water tank, comes into contact with the cooling medium and is rapidly cooled to form a plastic strip; the rapid cooling process includes a temperature gradient from the outer layer to the inside; during the process of the strip-shaped melt changing from a molten state to a solid state, it forms an instantaneous free volume or microporous structure, and the far-infrared liquid material and zinc ions enter the instantaneous free volume or microporous structure through capillary permeation, pressure difference drive or diffusion to complete pore filling and are fixed inside the plastic; S4. Drying and pelletizing: After cooling, the plastic strips are air-dried or hot-dried to remove the liquid medium and fix the far-infrared liquid material and zinc ions in the internal structure of the plastic. The strips are then pelletized to obtain plastic granules with far-infrared and zinc ion antibacterial functions.

2. The method for preparing plastic granules with far-infrared and zinc ion antibacterial functions according to claim 1, characterized in that, In step S1, the thermoplastic composite material includes a matrix resin and a functional masterbatch. The matrix resin is selected from one or more combinations of PE, PP, PS, ABS, and PET; and / or the functional masterbatch includes at least one of color masterbatch for plastic coloring, filler masterbatch, antioxidant masterbatch, UV resistant masterbatch, antistatic masterbatch, flame retardant masterbatch, antibacterial masterbatch, open-cell masterbatch, foaming masterbatch, and reinforcing masterbatch.

3. The method for preparing plastic granules with far-infrared and zinc ion antibacterial functions according to claim 1, characterized in that, In step S2, the far-infrared liquid material is an aqueous liquid material with far-infrared radiation characteristics, comprising microscopic particles of nano-metal oxides and / or micron-sized inorganic oxides; wherein, the nano-metal oxides are selected from at least one of titanium dioxide, aluminum oxide, iron oxide, manganese oxide, magnesium oxide, and calcium oxide, with a particle size of 10-50 nm; and the micron-sized inorganic oxides are inorganic oxides with far-infrared radiation characteristics in the 5-14 micron band.

4. The method for preparing plastic granules with far-infrared and zinc ion antibacterial functions according to claim 1, characterized in that, In step S2, the zinc ion solution is an aqueous solution of zinc oxide.

5. The method for preparing plastic granules with far-infrared and zinc ion antibacterial functions according to claim 1, characterized in that, In step S2, the far-infrared liquid material and zinc ions exist in the cooling medium in the form of a liquid dispersion, and the far-infrared liquid material maintains a stable dispersion state during the cooling process, so that it continuously provides permeable active particles during the process of the plastic strip changing from a molten state to a solid state, which enter and fill the instantaneous free volume or microporous structure inside the plastic strip.

6. The method for preparing plastic granules with far-infrared and zinc ion antibacterial functions according to claim 1, characterized in that, In step S2, the cooling water tank also contains a dispersing agent, which is selected from dispersants, surfactants, or combinations thereof.

7. The method for preparing plastic granules with far-infrared and zinc ion antibacterial functions according to claim 1, characterized in that, In step S3, the temperature of the cooling water tank is 30-60℃.

8. The method for preparing plastic granules with far-infrared and zinc ion antibacterial functions according to claim 1, characterized in that, In step S3, the cooling rate of the strip-shaped melt is 1-50°C / sec.

9. The method for preparing plastic granules with far-infrared and zinc ion antibacterial functions according to claim 1, characterized in that, In step S3, the residence time of the plastic strip in the cooling water tank is 0.5-30 seconds; the traction speed of the plastic strip is 1-150 m / min.

10. A functional plastic, characterized in that, The plastic granules with far-infrared and zinc ion antibacterial functions are prepared by the method described in any one of claims 1 to 7. The granules contain micropores or free volume structures formed by molten plastic during the cooling process of plastic strips. Far-infrared materials and antibacterial zinc ions are distributed in the micropores or free volume structures, and the far-infrared materials and antibacterial zinc ions are embedded in the internal structure formed by the cooling process.

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