Preparation Device and Method of an Ultraviolet-Resistant Plastic Masterbatch

Abstract

The present invention discloses a preparation device and method for an ultraviolet-resistant plastic masterbatch, comprising the steps of: S1, mixing 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxy benzophenone, and adding nano-titanium dioxide to form a premix; S2, mixing the premix in S1 with the carrier polyethylene; S3, adding a light stabilizer, an antioxidant and surface-modified calcium carbonate to the mixture in S2, and stirring and mixing to prepare a remix; S4, melt-blending the remix, matrix polyethylene and color powder, and extruding a plastic strip; S5, cooling the extruded plastic strip, cutting it into uniform plastic masterbatch, and removing unqualified particles by screening; by mixing 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxy benzophenone and adding nano-titanium dioxide, the present invention directly realizes the comprehensive absorption of ultraviolet rays in the UVA, UVB bands and part of the UVC band.

Description

Technical Field

[0001] The present invention relates to the technical field of compositions of polymer compounds, particularly to the technical field of polyethylene, and specifically to a preparation device and method for ultraviolet-resistant plastic masterbatch. Background Art

[0002] Ultraviolet light is an electromagnetic radiation with a wavelength shorter than visible light and higher energy than visible light. According to different wavelengths, ultraviolet light can be divided into three main bands: UVA, with a wavelength in the range of 320 - 400 nanometers, which can penetrate the ozone layer and glass and reach the Earth's surface, accounting for most of the ultraviolet light reaching the Earth's surface; UVB, with a wavelength in the range of 280 - 320 nanometers, most of which is absorbed by the ozone layer and only a small amount reaches the Earth's surface; UVC, with a wavelength in the range of 100 - 280 nanometers, which is almost entirely absorbed by the ozone layer and does not reach the Earth's surface. In the natural environment, people hardly come into contact with ultraviolet light in the UVC band.

[0003] With the wide application of polymer materials in various fields, especially the long-term use of plastic products in outdoor environments, their ultraviolet aging resistance performance has become an important technical challenge. Ultraviolet radiation, especially in the UVA and UVB bands, can break chemical bonds in plastics, resulting in color fading, strength reduction, embrittlement, and even fracture of the materials, thus shortening the service life of products. Therefore, it is particularly important to prepare plastic masterbatch with high-efficient ultraviolet resistance performance.

[0004] Although existing broad-spectrum ultraviolet absorbers can cover most of the wavelength ranges in the UVA and UVB bands, at certain specific wavelength points or regions, their absorption efficiency is not high enough; there are "gaps" or "valleys" in the absorption spectrum of broad-spectrum absorbers, making the absorption in the UVA and UVB bands of the entire absorption system discontinuous and non-smooth. This non-uniform absorption efficiency will affect the overall ultraviolet aging resistance performance of the product.

[0005] Therefore, it is necessary to improve the preparation method of ultraviolet-resistant plastic masterbatch in the prior art to solve the above problems. Summary of the Invention

[0006] The present invention overcomes the deficiencies of the prior art and provides a preparation device and method for ultraviolet-resistant plastic masterbatch, aiming to solve the problem that the absorption efficiency of existing broad-spectrum ultraviolet absorbers is not high at certain specific wavelength points or regions, resulting in the overall ultraviolet aging resistance performance of plastic masterbatch being affected.

[0007] To achieve the above object, the technical solution adopted by the present invention is: A preparation method for ultraviolet-resistant plastic masterbatch, comprising:

[0008] S1. Mix 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxy benzophenone, and add nano-titanium dioxide to form a premix;

[0009] S2. Mix the premix in S1 with the carrier polyethylene;

[0010] S3. Add a light stabilizer, an antioxidant, and surface-modified calcium carbonate to the mixture in S2, and stir and mix to prepare a remix;

[0011] S4. After melt-blending the remix, matrix polyethylene, and color powder, extrude a plastic strip;

[0012] S5. After cooling the extruded plastic strip, cut it into uniform plastic color masterbatches, and remove unqualified particles by screening.

[0013] In a preferred embodiment of the present invention, in step S1, the mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxy benzophenone, and nano-titanium dioxide is 11-16:5-10:1-8; the mixing speed is 800-1000 r / min, and the mixing time is 3-5 min.

[0014] In a preferred embodiment of the present invention, in step S2, the mass ratio of the premix to the carrier polyethylene is 1:2-5, the mixing speed is 500-800 r / min, and the mixing time is 5-8 min.

[0015] In a preferred embodiment of the present invention, in step S3, the mass ratio of the mixture, light stabilizer, antioxidant, and surface-modified calcium carbonate is 1:0.1-0.3:0.05-0.2:0.1-0.5; the mixing speed is 800-1000 r / min, and the mixing time is 5-8 min.

[0016] In a preferred embodiment of the present invention, in step S4, the mass ratio of the remix, matrix polyethylene, and color powder is 1:20-35:15:25.

[0017] In a preferred embodiment of the present invention, in step S4, the remix, matrix polyethylene, and color powder are added to a melting device, the melting temperature in the feeding zone is 160-180 °C, the melting temperature in the melting zone is 180-200 °C, the melting temperature in the metering zone is 200-220 °C, the melting pressure is 3-5 bar, the mixing speed is 40-60 r / min, and the melt-blending time is 15-20 min.

[0018] In a preferred embodiment of the present invention, the size of the nano-titanium dioxide is 20-40 nanometers.

[0019] In a preferred embodiment of the present invention, the carrier polyethylene and the matrix polyethylene are linear low-density polyethylene, and the density of the linear low-density polyethylene is 0.92 - 0.94 g / cm 3 .

[0020] In a preferred embodiment of the present invention, in step S5, the plastic strip is cooled in stages in cooling water. The temperature of the cooling water in the initial cooling stage is 10 - 20 °C; the temperature of the cooling water in the intermediate cooling stage is 20 - 30 °C; the temperature of the cooling water in the final cooling stage is 30 - 40 °C.

[0021] The present invention provides a preparation device for ultraviolet-resistant plastic masterbatch, comprising:

[0022] A high-speed mixer, which is used to mix 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone and nano-titanium dioxide to form a premix; it is also used to mix the premix with carrier polyethylene, and to mix the mixture, light stabilizer, antioxidant and surface-modified calcium carbonate;

[0023] A twin-screw extruder: melting and blending the remix, matrix polyethylene and color powder to form a uniform melt;

[0024] A temperature control system, which is set in the twin-screw extruder to monitor and adjust the temperature of different regions to ensure the uniformity of the melting process and the quality of the product;

[0025] An extrusion die, which is located at the outlet of the melting equipment and is used to mold and extrude the molten plastic mixture to form a continuous plastic strip;

[0026] A cooling water tank, which cools the extruded plastic strip to solidify it;

[0027] A granulator, which is used to cut the cooled plastic strip into uniform plastic masterbatch;

[0028] A screening machine, which is used to remove unqualified plastic masterbatch particles.

[0029] The present invention solves the defects in the background technology, and the present invention has the following beneficial effects:

[0030] (1) The present invention forms a premix by mixing 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone and nano-titanium dioxide, mixes it with carrier polyethylene, light stabilizer, antioxidant and surface-modified calcium carbonate, then melts and blends it with matrix polyethylene and color powder, and finally extrudes, cools, granulates and screens to prepare an ultraviolet-resistant plastic masterbatch.

[0031] (2) In the present invention, 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxy benzophenone are mixed in step S1, and nano-titanium dioxide is added, directly achieving comprehensive absorption of ultraviolet rays in the UVA, UVB bands and part of the UVC band; 2-(2'-hydroxy-5'-methylphenyl) benzotriazole mainly absorbs UVA and part of UVB, 2-hydroxy-4-methoxy benzophenone mainly absorbs UVB and part of UVA, and nano-titanium dioxide provides absorption of UVB and part of UVC. The combination of the three forms a complementary absorption system, improving the overall ultraviolet protection effect. Compared with the prior art, the ultraviolet aging resistance of the material is further improved.

[0032] (3) In the present invention, surface-modified calcium carbonate is mixed in the ultraviolet absorbing material. By improving the surface properties of the material, the bonding force with the carrier polyethylene and the matrix polyethylene is increased, the interfacial defects and stress concentration are reduced. The surface-modified calcium carbonate and the premix form a complementarity, providing ultraviolet protection in a wider wavelength range. Compared with the prior art, the overall stability and weather resistance of the material are enhanced.

[0033] (4) In the present invention, the premix is mixed with the carrier polyethylene. Linear low-density polyethylene is used as the carrier. Its good flexibility, impact resistance, and compatibility with the premix ensure the uniform dispersion of the premix during processing and use, reduce migration and precipitation, improve the mixing uniformity, and enhance the stability of the plastic masterbatch.

[0034] (5) Through the setting of the temperature control system in the twin-screw extruder in the present invention, the uniformity of the melting process and the quality of the product are ensured. The temperature control system can monitor and adjust the temperature in different regions, making the melting process more uniform and stable, avoiding problems such as premature over-melting, decomposition or incomplete melting of the material caused by too high or too low temperature, thereby ensuring the quality and performance of the plastic masterbatch. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings;

[0036] Figure 1 It is a flow chart of the preferred embodiment of the present invention. Detailed Embodiments

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] In the following description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0039] A preparation method of an ultraviolet-resistant plastic masterbatch includes the steps of:

[0040] S1. Mix 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxybenzophenone, and add nano-titanium dioxide to form a premix;

[0041] S2. Mix the premix in S1 with the carrier polyethylene;

[0042] S3. Add a light stabilizer, an antioxidant, and surface-modified calcium carbonate to the mixture in S2, and stir and mix to prepare a remix;

[0043] S4. After melt-blending the remix, matrix polyethylene, and color powder, extrude a plastic strip;

[0044] S5. After cooling the extruded plastic strip, cut it into uniform plastic masterbatch particles, and remove unqualified particles by screening;

[0045] Specifically, in step S1, the mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, and nano-titanium dioxide is 11-16:5-10:1-8; the mixing speed is 800-1000 r / min, the mixing time is 3-5 min; the size of the nano-titanium dioxide is 20-40 nanometers;

[0046] In step S1, 2-(2'-hydroxy-5'-methylphenyl) benzotriazole mainly absorbs ultraviolet rays in the UVA band and part of the UVB band, and can effectively convert the absorbed ultraviolet energy into harmless heat energy, thereby protecting plastics from ultraviolet damage; the conjugation between the benzene ring and the triazole ring enhances the molecule's absorption ability for ultraviolet rays in the UVA and UVB bands; 2-(2'-hydroxy-5'-methylphenyl) benzotriazole has high photo-stability and thermal stability; 2-hydroxy-4-methoxybenzophenone mainly absorbs ultraviolet rays in the UVB band and part of the UVA band. When the 2-hydroxy-4-methoxybenzophenone molecule absorbs ultraviolet rays, the electrons inside the molecule are excited to a higher energy level. This excited state is unstable, so the molecule will quickly release the absorbed energy in the form of heat, thereby protecting the material from ultraviolet damage.

[0047] Mixing these two ultraviolet absorbers can cover a wider ultraviolet band, thereby providing more comprehensive protection. Benzotriazole absorbers mainly absorb UVA, while benzophenone absorbers mainly absorb UVB. This combination can ensure good absorption in the entire UVA and UVB bands. Mixing can reduce the "gaps" or "valleys" in the absorption spectrum, making the absorption of the entire absorption system more continuous and smooth in the UVA and UVB bands, thereby improving the overall ultraviolet aging resistance of the material.

[0048] In step S1, nano-titanium dioxide is added as a material to expand the spectral band. Nano-titanium dioxide provides absorption of UVB and part of UVC, and has photocatalytic properties; it forms a complement with the mixed absorption band of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxybenzophenone, thereby improving the overall ultraviolet protection effect. Due to the size effect of 20-40 nanometers, nano-titanium dioxide can scatter ultraviolet rays, reducing the amount of ultraviolet rays directly penetrating the material, helping to reduce the absorption pressure of the material on ultraviolet rays, and thus indirectly improving the ultraviolet resistance of the material.

[0049] Specifically, in step S2, the carrier polyethylene uses linear low-density polyethylene. The mass ratio of the premix to the carrier polyethylene is 1:2-5, the mixing speed is 500-800 r / min, and the mixing time is 5-8 min; the density of the linear low-density polyethylene is 0.92-0.94 g / cm 3 .

[0050] Linear low-density polyethylene not only has good flexibility and impact resistance, but also its molecular structure makes it have good compatibility with the premix. As a carrier, it can evenly disperse the premix, reduce the migration and precipitation of the premix during processing and use, and improve the mixing uniformity.

[0051] Specifically, in step S3, the mass ratio of the mixture, light stabilizer, antioxidant, and surface-modified calcium carbonate is 1: 0.1 - 0.3: 0.05 - 0.2: 0.1 - 0.5; the mixing speed is 800 - 1000 r / min, and the mixing time is 5 - 8 min;

[0052] The main function of the light stabilizer is to absorb, reflect, or scatter ultraviolet rays. It synergistically acts with 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxybenzophenone in S1 to prevent the destruction of plastic materials by ultraviolet rays. It can quench or capture free radicals generated by ultraviolet irradiation to further protect the material; the light stabilizer is one or more mixtures of 2-hydroxy-4-n-octyloxybenzophenone, nickel bis(octyldithiocarbamate), and Tinuvin 770;

[0053] The antioxidant is used to inhibit the performance degradation of linear low-density polyethylene caused by oxidation reactions during processing, storage, and use, and to maintain the color stability and physical properties of the plastic masterbatch; the antioxidant is one or more mixtures of butylated hydroxytoluene, N-phenyl-N'-isopropyl-p-phenylenediamine, and dilauryl thiodipropionate;

[0054] The preparation method of the surface-modified calcium carbonate includes:

[0055] Grind calcium carbonate into particles with a size of 40 - 60 nanometers. Add the calcium carbonate particles to a modifier solution with a concentration of 1% - 5%. The stirring speed is 500 - 1000 r / min, and the stirring duration is 30 - 60 min. Then dry the calcium carbonate particles at 80 - 120 °C for 60 min - 120 min; finally, cure the calcium carbonate particles at 150 - 200 °C to form surface-modified calcium carbonate; the modifier solution is prepared from a silane coupling agent and stearic acid with a concentration ratio of 0.4 - 0.6: 1. Stearic acid contains polar groups such as carboxyl groups, which can form chemical bonds with calcium ions on the surface of calcium carbonate, thereby forming a coating film on the surface of calcium carbonate particles. This coating film can improve the lipophilicity and dispersibility of calcium carbonate, making it easier to disperse uniformly in the polymer; the silane coupling agent can act as a bridge between calcium carbonate and stearic acid;

[0056] The surface-modified calcium carbonate can produce a synergistic effect with the materials in the premix. The surface-modified calcium carbonate particles have a large specific surface area, which can scatter ultraviolet rays and reduce the chance of ultraviolet rays directly penetrating the material; the benzotriazole absorbent in the premix mainly absorbs UVA, while the benzophenone absorbent mainly absorbs UVB. Nano-titanium dioxide provides the absorption of UVB and part of UVC. After combining with the surface-modified calcium carbonate, it can provide effective ultraviolet protection in a wider wavelength range;

[0057] Surface-modified calcium carbonate can act on the carrier polyethylene and the matrix polyethylene. By improving its surface properties, the surface-modified calcium carbonate enhances its lipophilicity and dispersibility, making its combination with the carrier polyethylene and the matrix polyethylene closer, reducing interfacial defects and stress concentration, and thus improving the overall stability and weather resistance of the material.

[0058] Specifically, in step S4, the matrix polyethylene uses linear low-density polyethylene, and the mass ratio of the re-mixture, the matrix polyethylene, and the color powder is 1:20 - 35:15:25. They are added to the melting equipment. The melting temperature in the feeding zone is 160 - 180 °C, the melting temperature in the melting zone is 180 - 200 °C, the melting temperature in the metering zone is 200 - 220 °C, the melting pressure is 3 - 5 bar, the mixing speed is 40 - 60 r / min, and the melt blending time is 15 - 20 min. The density of the linear low-density polyethylene is 0.92 - 0.94 g / cm 3 。

[0059] The main purpose of the feeding zone is to preheat, making it start to soften and gradually melt, while avoiding excessive premature melting or decomposition of the material due to too high a temperature. The melting zone is the main melting area where the re-mixture, the matrix polyethylene, and the color powder are completely melted to form a uniform melt. The melt in the metering zone is further homogenized to ensure the uniformity and consistency of the mixture, eliminating the temperature gradient and the incompletely melted parts in the melt.

[0060] Specifically, in step S4, the melt is extruded from the outlet of the melting equipment, passes through the die at the outlet, and is formed and extruded to form a continuous strip, namely the plastic strip. The diameter of the die is 1 - 5 mm, and the die temperature matches the melting temperature during the extrusion process, which is 180 - 220 °C.

[0061] Specifically, in step S5, the plastic strip enters the cooling water for segmented cooling. When the plastic strip first enters the cooling water, due to its high temperature, a lower cooling water temperature is set to quickly take away the heat and avoid deformation of the plastic strip. The cooling water temperature in the initial cooling section is 10 - 20 °C. As the plastic strip advances in the cooling water, its temperature gradually decreases. At this time, the cooling water temperature is increased to maintain a certain cooling efficiency while avoiding cracking of the plastic strip due to too large a temperature difference. The cooling water temperature in the middle cooling section is 20 - 30 °C. Before the plastic strip is about to be completely cooled and solidified, the cooling water temperature is further increased to ensure a uniform cooling effect on both the surface and inside of the plastic strip. The cooling water temperature in the final cooling section is 30 - 40 °C.

[0062] Specifically, the cutting length of the plastic masterbatch is 5 - 8 mm.

[0063] A preparation device for an ultraviolet-resistant plastic masterbatch, comprising:

[0064] A high-speed mixer is used to mix 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxy benzophenone and nano-titanium dioxide to form a premix; it is also used to mix the premix with the carrier polyethylene, and to mix the mixture, light stabilizer, antioxidant and surface-modified calcium carbonate;

[0065] A twin-screw extruder: melts and blends the remix, matrix polyethylene and color powder to form a uniform melt;

[0066] A temperature control system is set in the twin-screw extruder to monitor and adjust the temperatures of different zones to ensure the uniformity of the melting process and the quality of the products;

[0067] An extrusion die is located at the outlet of the melting equipment and is used to shape and extrude the molten plastic mixture to form a continuous plastic strip;

[0068] A cooling water tank cools the extruded plastic strip to solidify it;

[0069] A pelletizer is used to cut the cooled plastic strip into uniform plastic masterbatch pellets;

[0070] A screening machine is used to remove unqualified plastic masterbatch particles.

[0071] Example 1

[0072] A preparation method of an ultraviolet-resistant plastic masterbatch includes the steps:

[0073] S1. Mix 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxy benzophenone, and add nano-titanium dioxide to form a premix; specifically, the mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxy benzophenone and nano-titanium dioxide is 13:7:5; the mixing speed is 900 r / min, the mixing time is 4 min; the size of the nano-titanium dioxide is 25 nanometers;

[0074] S2. Mix the premix in S1 with the carrier polyethylene; the carrier polyethylene is linear low-density polyethylene, and the mass ratio of the premix to the carrier polyethylene is 1:3, the mixing speed is 600 r / min, the mixing time is 6 min; the density of the linear low-density polyethylene is 0.93 g / cm 3 ;

[0075] S3. Add 2-hydroxy-4-n-octyloxy benzophenone, butylated hydroxytoluene and surface-modified calcium carbonate to the mixture in S2, and stir and mix to prepare a remix; the mass ratio of the mixture, light stabilizer, antioxidant and surface-modified calcium carbonate is 1:0.2:0.1:0.3; the mixing speed is 900 r / min, the mixing time is 6 min;

[0076] S4. After melting and blending the remix, matrix polyethylene, and color powder, extrude a plastic strip; the matrix polyethylene is linear low-density polyethylene, and the mass ratio of the remix, matrix polyethylene, and color powder is 1:25:15:25; add them to the melting equipment, the melting temperature in the feeding zone is 170 °C, the melting temperature in the melting zone is 190 °C, the melting temperature in the metering zone is 210 °C, the melting pressure is 4 bar, the mixing speed is 50 r / min, and the melting and blending time is 18 min; the density of the linear low-density polyethylene is 0.93 g / cm 3 ; the die diameter is 5 mm;

[0077] S5. After cooling the extruded plastic strip, cut it into uniform plastic masterbatch pellets, and the cutting length of the plastic masterbatch pellets is 8 mm, and remove unqualified particles by screening; the plastic strip is cooled by the water cooling method. Specifically, the plastic strip enters the cooling water for segmented cooling. When the plastic strip first enters the cooling water, the initial cooling section of the cooling water temperature is 15 °C; as the plastic strip advances in the cooling water, the middle cooling section of the cooling water temperature is 25 °C; before the plastic strip is about to be completely cooled and solidified, the final cooling section of the cooling water temperature is 35 °C.

[0078] Example 2

[0079] A method for preparing an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be described in detail. The differences between this example and Example 1 are as follows;

[0080] The mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, and nano-titanium dioxide is 13:5:5.

[0081] Example 3

[0082] A method for preparing an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be described in detail. The differences between this example and Example 1 are as follows;

[0083] The mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, and nano-titanium dioxide is 13:9:5.

[0084] Example 4

[0085] A method for preparing an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be described in detail. The differences between this example and Example 1 are as follows;

[0086] The mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, and nano-titanium dioxide is 11:7:5.

[0087] Example 5

[0088] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be repeated here. The difference between this example and Example 1 is that;

[0089] The mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone and nano-titanium dioxide is 15:7:5.

[0090] Example 6

[0091] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be repeated here. The difference between this example and Example 1 is that;

[0092] The mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone and nano-titanium dioxide is 11:5:5.

[0093] Example 7

[0094] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be repeated here. The difference between this example and Example 1 is that;

[0095] The mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone and nano-titanium dioxide is 15:5:5.

[0096] Example 8

[0097] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be repeated here. The difference between this example and Example 1 is that;

[0098] The mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone and nano-titanium dioxide is 11:9:5.

[0099] Example 9

[0100] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be repeated here. The difference between this example and Example 1 is that.

[0101] The mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone and nano-titanium dioxide is 15:9:5.

[0102] Example 10

[0103] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be described again. The difference between this example and Example 1 lies in that.

[0104] The mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone and nano-titanium dioxide is 13:7:3.

[0105] Example XI

[0106] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be described again. The difference between this example and Example 1 lies in that;

[0107] The mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone and nano-titanium dioxide is 13:7:7.

[0108] Example XII

[0109] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be described again. The difference between this example and Example 1 lies in that;

[0110] The size of the nano-titanium dioxide is 20 nanometers.

[0111] Example XIII

[0112] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 1 will not be described again. The difference between this example and Example 1 lies in that;

[0113] The size of the nano-titanium dioxide is 30 nanometers.

[0114] Example XIV

[0115] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 10 will not be described again. The difference between this example and Example 10 lies in that;

[0116] The size of the nano-titanium dioxide is 20 nanometers.

[0117] Example XV

[0118] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example 10 will not be described again. The difference between this example and Example 10 lies in that;

[0119] The size of the nano-titanium dioxide is 30 nanometers.

[0120] Example XVI

[0121] A preparation method of an ultraviolet-resistant plastic masterbatch, the same parts as in Example XI will not be described again. The difference between this example and Example XI lies in that;

[0122] The size of the nano-titanium dioxide is 20 nanometers.

[0123] Example XVII

[0124] A method for preparing an ultraviolet-resistant plastic masterbatch, the same parts as in Example XI will not be described in detail. The difference between this example and Example XI lies in;

[0125] The size of the nano-titanium dioxide is 30 nanometers.

[0126] Example XVIII

[0127] A method for preparing an ultraviolet-resistant plastic masterbatch, the same parts as in Example I will not be described in detail. The difference between this example and Example I lies in;

[0128] The mass ratio of the surface-modified calcium carbonate is different; specifically, the mass ratio of the mixture, light stabilizer, antioxidant, and surface-modified calcium carbonate is 1:0.2:0.1:0.1.

[0129] Example XIX

[0130] A method for preparing an ultraviolet-resistant plastic masterbatch, the same parts as in Example I will not be described in detail. The difference between this example and Example I lies in;

[0131] The mass ratio of the surface-modified calcium carbonate is different; specifically, the mass ratio of the mixture, light stabilizer, antioxidant, and surface-modified calcium carbonate is 1:0.2:0.1:0.2.

[0132] Example XX

[0133] A method for preparing an ultraviolet-resistant plastic masterbatch, the same parts as in Example I will not be described in detail. The difference between this example and Example I lies in;

[0134] The mass ratio of the surface-modified calcium carbonate is different; specifically, the mass ratio of the mixture, light stabilizer, antioxidant, and surface-modified calcium carbonate is 1:0.2:0.1:0.4.

[0135] Example XXI

[0136] A method for preparing an ultraviolet-resistant plastic masterbatch, the same parts as in Example I will not be described in detail. The difference between this example and Example I lies in;

[0137] The mass ratio of the surface-modified calcium carbonate is different; specifically, the mass ratio of the mixture, light stabilizer, antioxidant, and surface-modified calcium carbonate is 1:0.2:0.1:0.5.

[0138] Comparative Example I

[0139] This comparative example provides a method for preparing an ultraviolet-resistant plastic masterbatch. The same parts as in Example 1 will not be elaborated. The differences between this comparative example and Example 1 are as follows:

[0140] This comparative example does not add nano-titanium dioxide.

[0141] Comparative Example 2

[0142] This comparative example provides a method for preparing an ultraviolet-resistant plastic masterbatch. The same parts as in Example 1 will not be elaborated. The differences between this comparative example and Example 1 are as follows:

[0143] This comparative example does not add surface-modified calcium carbonate.

[0144] Comparative Example 3

[0145] This comparative example provides a method for preparing an ultraviolet-resistant plastic masterbatch. The same parts as in Example 1 will not be elaborated. The differences between this comparative example and Example 1 are as follows:

[0146] In step S2 of this comparative example, carrier polyethylene is not added for mixing.

[0147] Test Example 1

[0148] In this test example, Examples 1 to 9 were selected for experiments to study the effects of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxybenzophenone with different ratios on the properties of the prepared ultraviolet-resistant plastic masterbatch; 2-(2'-hydroxy-5'-methylphenyl) benzotriazole mainly absorbs ultraviolet rays in the UVA band and part of the UVB band; 2-hydroxy-4-methoxybenzophenone mainly absorbs ultraviolet rays in the UVB band and part of the UVA band; by changing the mass ratio of these two components, their effects on the ultraviolet resistance, color stability, processing performance, etc. of the plastic masterbatch were analyzed in order to find the best ratio combination.

[0149] An anti-ultraviolet experiment was carried out. A xenon lamp was used to simulate sunlight. The temperature during ultraviolet irradiation was 60±20°C; the relative humidity was 50%; the irradiation duration was 1000 hours; the release force after aging and the retention rate of the elongation at break after aging were tested, and the color difference value ΔE was calculated using a color difference meter;

[0150] Ultraviolet transmittance test: An ultraviolet transmittance tester was used to measure the ultraviolet transmittance of plastic masterbatch samples prepared in different examples and comparative examples. The lower the transmittance, the stronger the ability of the sample to block ultraviolet rays and the better the ultraviolet resistance performance.

[0151] Table 1 Experimental comparison results of Test Example 1

[0152]

[0153]

[0154] 2-(2'-Hydroxy-5'-methylphenyl) benzotriazole mainly absorbs ultraviolet rays in the UVA band and part of the UVB band, while 2-hydroxy-4-methoxybenzophenone mainly absorbs ultraviolet rays in the UVB band and part of the UVA band. There is a certain overlap in the absorption bands of these two ultraviolet absorbers, but each has its own emphasis; when the mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole: 2-hydroxy-4-methoxybenzophenone is adjusted to 13:7, it can maximize the coverage of the UVA and UVB bands, reduce the "gaps" or "valleys" in the absorption spectrum, make the absorption of the whole absorption system more continuous and smooth in the UVA and UVB bands, and avoid the damage of ultraviolet rays to the mechanical properties and color stability of plastic masterbatch.

[0155] The conjugation between the benzene ring and the triazole ring in the molecular structure of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole enhances its ability to absorb ultraviolet rays. After the molecule of 2-hydroxy-4-methoxybenzophenone absorbs ultraviolet rays, it can quickly release energy in the form of heat energy to protect the plastic masterbatch.

[0156] Judging from the experimental results, Example 1 has good effects on the physical properties and ultraviolet absorption properties of the plastic masterbatch after ultraviolet resistance. To sum up, Example 1 has the best effect when the mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole to 2-hydroxy-4-methoxybenzophenone is set at 13:7. This is mainly due to the good complementarity of the two in the ultraviolet absorption band, high light stability and thermal stability, uniformity in the mixing process, and excellent processing performance and final performance.

[0157] Test Example 2

[0158] On the basis of Test Example 1, this test example selects Example 1, Examples 10 to 17, and Comparative Example 1 to repeat the experiment of Experiment 1; to study the effects of the content and size of nano-titanium dioxide on 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxybenzophenone, and the overall impact on plastic masterbatch.

[0159] Table 2 Experimental comparison results of Test Example 2

[0160]

[0161] When the size of nano-titanium dioxide is 25 nanometers, it can scatter ultraviolet light more effectively. The smaller the size of the nanoparticles, the larger their specific surface area, and generally the better the scattering effect. However, when the size is too small, nano-titanium dioxide is prone to agglomeration and cannot be evenly mixed when mixed with 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxybenzophenone, which affects the scattering effect. At around 25 nanometers, nano-titanium dioxide can maintain good dispersibility and at the same time provide strong scattering ability. Nano-titanium dioxide provides the absorption of UVB and part of UVC, expands the absorption spectrum range of ultraviolet light, reduces the chance of ultraviolet light directly penetrating the material, and reduces the degradation of the color of the plastic masterbatch by ultraviolet light. Nano-titanium dioxide not only has a scattering effect but also has photocatalytic performance, which can further decompose harmful substances caused by ultraviolet light. At this size of 25 nanometers, the photocatalytic activity of nano-titanium dioxide is relatively high, which can further decompose free radicals caused by ultraviolet light and protect the material from damage.

[0162] Experimental Example III

[0163] On the basis of Experimental Examples I and II, this experimental example selects Example I, Examples XVIII to XXI, and Comparative Example II to repeat the experiment in Experiment I; to study the influence of the quality of surface-modified calcium carbonate on the ultraviolet absorption of the premix and the overall influence on the plastic masterbatch.

[0164] Table 2 Experimental Comparison Results of Experimental Example III

[0165]

[0166] Judging from the above-mentioned invention content and experimental data, surface-modified calcium carbonate plays an important role in the preparation of ultraviolet-resistant plastic masterbatch. Through its large specific surface area, surface-modified calcium carbonate can scatter ultraviolet light, further expand the absorption spectrum range of ultraviolet light, reduce the chance of ultraviolet light directly penetrating the material, and thus improve the ultraviolet resistance of the material. At the same time, surface-modified calcium carbonate produces a synergistic effect with other components in the premix, enhancing the overall ultraviolet protection ability. In Example I, the best effect is achieved when the mass ratio of surface-modified calcium carbonate is 0.3. The surface-modified calcium carbonate is modified by stearic acid to form a chemically bonded coating film, which improves the lipophilicity and dispersibility. This modification not only enhances the compatibility of calcium carbonate with the premix and the carrier polyethylene but also helps to disperse more evenly in the matrix polyethylene. Due to surface modification, the modified calcium carbonate particles are more tightly combined with the polymer, reducing interface defects and stress concentration, thereby improving the overall stability and weather resistance of the material and significantly enhancing the ultraviolet resistance of the plastic masterbatch.

[0167] In Comparative Example 3, the carrier polyethylene was not added. The results showed that both the retaining rates of the tripping force and the elongation at break after aging decreased, the color difference value increased, and the ultraviolet transmittance increased. This indicates that the addition of carrier polyethylene is crucial for improving the overall performance of the material. The main role of carrier polyethylene is to act as a carrier before melting and blending each component with matrix polyethylene, evenly disperse the premix, reduce migration and precipitation, and improve the mixing uniformity. Each material adheres evenly to the carrier polyethylene, and there is good compatibility between the carrier polyethylene and the matrix polyethylene. The combination of the two can produce a UV-resistant plastic masterbatch with uniform components. The absence of carrier polyethylene will lead to uneven distribution of the premix during processing and use, affecting the stability and weather resistance of the material.

[0168] Based on the ideal embodiments of the present invention as an inspiration, through the above description, relevant personnel can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A preparation method of an ultraviolet-resistant plastic masterbatch, characterized in that Including the steps: S1. Mix 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-methoxy benzophenone, and add nano-titanium dioxide to form a premix; S2. Mix the premix in S1 with the carrier polyethylene; S3. Add a light stabilizer, an antioxidant and surface-modified calcium carbonate to the mixture in S2, and stir and mix to prepare a remix; S4. After melt-blending the remix, matrix polyethylene and color powder, extrude a plastic strip; S5. After cooling the extruded plastic strip, cut it into uniform plastic color masterbatch, and remove unqualified particles by screening; In step S1, the mass ratio of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-methoxy benzophenone and nano-titanium dioxide is 11-16:5-10:1-8; the mixing speed is 800-1000 r / min, and the mixing time is 3-5 min; In step S3, the mass ratio of the mixture, light stabilizer, antioxidant and surface-modified calcium carbonate is 1:0.1-0.3:0.05-0.2:0.1-0.5; the mixing speed is 800-1000 r / min, and the mixing time is 5-8 min.

2. The preparation method of an ultraviolet-resistant plastic masterbatch according to claim 1, characterized in that: In step S2, the mass ratio of the premix to the carrier polyethylene is 1:2-5, the mixing speed is 500-800 r / min, and the mixing time is 5-8 min.

3. The preparation method of an ultraviolet-resistant plastic masterbatch according to claim 1, characterized in that: In step S4, the mass ratio of the remix, matrix polyethylene and color powder is 1:20-35:15:

25.

4. The preparation method of an ultraviolet-resistant plastic masterbatch according to claim 1, characterized in that: In step S4, the remix, matrix polyethylene and color powder are added to a melting device, the melting temperature in the feeding zone is 160-180 °C, the melting temperature in the melting zone is 180-200 °C, the melting temperature in the metering zone is 200-220 °C, the melting pressure is 3-5 bar, the mixing speed is 40-60 r / min, and the melt-blending time is 15-20 min.

5. The preparation method of an ultraviolet-resistant plastic masterbatch according to claim 1, characterized in that: The size of the nano-titanium dioxide is 20-40 nanometers.

6. The preparation method of an ultraviolet-resistant plastic masterbatch according to claim 1, wherein: The carrier polyethylene and the matrix polyethylene are linear low density polyethylene, and the density of the linear low density polyethylene is 0.92 - 0.94 g / cm 3 .

7. The preparation method of an ultraviolet-resistant plastic masterbatch according to claim 1, characterized in that: In step S5, the plastic strip enters the cooling water for segmented cooling. The cooling water temperature in the initial cooling section is 10-20 °C; the cooling water temperature in the middle cooling section is 20-30 °C; the cooling water temperature in the final cooling section is 30-40 °C.

Images