A plastic masterbatch and its preparation method

Abstract

This invention relates to the field of plastic masterbatch preparation technology, and in particular to a plastic masterbatch and its preparation method. The plastic masterbatch of this invention uses light calcium carbonate as the main filler, and activates and modifies the light calcium carbonate with polydimethylsiloxane, α-olefin sulfonate, alkyl polysaccharide glycoside, and nanocellulose to impart excellent processing fluidity, self-dispersibility, mechanical properties, anti-aging properties, and biodegradability. Using polypropylene and polystyrene as plastic masterbatches can further improve the transparency of the plastic masterbatch, enhance its oxygen and water vapor barrier properties, lower the melting temperature of the plastic masterbatch, and improve the fluidity of the melt, facilitating molding and processing to obtain lightweight, high-strength, stable, and impact-resistant biodegradable plastic masterbatches. This solves the problems of poor dispersion of light calcium carbonate in plastic masterbatches in existing technologies, resulting in poor mechanical properties and poor biodegradability of the prepared plastic masterbatches.

Description

Technical Field

[0001] This invention relates to the field of plastic masterbatch preparation technology, and in particular to a plastic masterbatch and its preparation method. Background Technology

[0002] Plastics are widely used in many fields due to their advantages such as light weight, high strength, stable chemical properties, and low cost. The plastics industry has developed rapidly, but there is still no proper method for disposing of used plastics, resulting in serious pollution of the natural environment from plastic waste. Discarding plastic waste pollutes the environment, burying it encroaches on land, and burning it pollutes the air. The fundamental solution is to develop biodegradable plastic masterbatches to replace non-biodegradable ones.

[0003] Furthermore, heavy calcium carbonate is currently widely used as a filler in the production of plastic masterbatches. Due to the poor dispersibility of heavy calcium carbonate, the quality of plastic products processed from masterbatches varies considerably. Additionally, improper formulation materials can lead to the non-rapid degradation of most plastic masterbatches, causing irreversible environmental pollution.

[0004] Light calcium carbonate, as another common filler material, not only has a positive impact on the performance of plastic masterbatches but also offers economic advantages. Currently, research progress has been made in using light calcium carbonate as a filler to prepare plastic masterbatches. For example, Chinese invention patent CN104250392A discloses a polypropylene-calcium carbonate filler masterbatch and its preparation method. This method mainly utilizes light calcium carbonate treated with a coupling agent to modify polypropylene filler, thereby improving the low-temperature impact strength, flexural modulus, and load deformation temperature of the polypropylene-calcium carbonate filler masterbatch. Chinese invention patent CN105885227A discloses a polypropylene film modification masterbatch and its preparation method. This method mainly involves modifying polypropylene and compounding it with linear low-density polyethylene, light calcium carbonate, oxidized polyethylene, and tert-butylhydroquinone to obtain a polypropylene masterbatch with excellent heat resistance.

[0005] However, given the urgent need to improve the dispersibility of light calcium carbonate in plastic masterbatches, enhance the quality of plastic products, and meet the current demand for environmentally friendly and biodegradable materials, how to further optimize the formulation of plastic masterbatches to achieve efficient dispersion of light calcium carbonate in plastic masterbatches, while improving the mechanical properties of plastic masterbatches and enhancing their biodegradability, thus making them more environmentally friendly, remains a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a plastic masterbatch and its preparation method. The plastic masterbatch of this invention has excellent mechanical properties and biodegradable properties.

[0007] This invention provides a plastic masterbatch comprising the following raw materials in parts by weight: 46-93 parts of light calcium carbonate, 0.1-0.8 parts of polydimethylsiloxane, 0.1-0.3 parts of α-olefin sulfonate, 0.1-0.3 parts of alkyl polysaccharide, 0.7-1.8 parts of superdispersant SP-830, and 0.5-15 parts of nanocellulose;

[0008] The plastic masterbatch contains polypropylene and polystyrene.

[0009] The plastic masterbatch of this invention uses light calcium carbonate as the main filler, and activates and modifies the light calcium carbonate using polydimethylsiloxane, α-olefin sulfonate, alkyl polysaccharide, superdispersant SP-830, and nanocellulose. Polydimethylsiloxane acts as a release agent and lubricant; α-olefin sulfonate acts as an antistatic agent and emulsifier; and alkyl polysaccharide acts as an emulsifier and dispersant. It also exhibits excellent biodegradability and surface activity. The superdispersant SP-830 helps improve the dispersibility and compatibility of light calcium carbonate in polymers, and it possesses excellent processing fluidity, self-dispersibility, and water resistance, significantly improving the mechanical properties of the composite material, making it more environmentally friendly and energy-saving. Nanocellulose not only improves the mechanical properties of the plastic masterbatch and reduces the weight of the product, but also possesses degradable and recyclable properties, making the plastic masterbatch more easily degradable and environmentally friendly while enhancing mechanical properties.

[0010] Finally, plastic materials using polypropylene and polystyrene as plastic masterbatches can further improve the transparency of plastic masterbatches, enhance their ability to block oxygen and water vapor, reduce the melting temperature of plastic masterbatches, and improve the fluidity of the melt, making it easier to mold and process into lightweight, high-strength, stable, and impact-resistant biodegradable plastic masterbatches.

[0011] As a preferred embodiment of this technical solution, the particle size of the light calcium carbonate used in this invention is preferably <5μm, and its calcium carbonate content is >95%.

[0012] In a preferred embodiment of this technical solution, the polypropylene is a random copolymer of polypropylene, and the polystyrene is high-impact polystyrene.

[0013] Random copolymers of polypropylene not only improve the transparency of plastic masterbatches and reduce haze, but also have higher impact resistance and better flexibility compared to homopolymers of polypropylene. At the same time, the lower melting temperature of random copolymers of polypropylene makes them easier to handle during processing, and also reduces the hot-melt temperature, improving processing efficiency. Random copolymers of polypropylene can also effectively block oxygen and water vapor, better preventing the aging of plastic products and enhancing their overall environmental friendliness.

[0014] High-impact polystyrene (HIPP) significantly improves the impact resistance of polystyrene by adding polybutadiene rubber particles and linking them together through grafting. HIPP also exhibits good processability, allowing for molding through injection molding, extrusion, blow molding, and other methods. Furthermore, HIPP has some resistance to oil and water, imparting certain water and oil resistance properties to plastic masterbatches. It also demonstrates good dimensional stability after molding, maintaining a stable shape and size. Finally, as a thermoplastic, HIPP has excellent recyclability, contributing to reduced environmental pollution.

[0015] Secondly, the present invention also provides a method for preparing the above-mentioned plastic masterbatch, comprising the following steps:

[0016] S1. Light calcium carbonate, polydimethylsiloxane, α-olefin sulfonate, alkyl polysaccharide and superdispersant SP-830 are put into a high-speed mixer and mixed to obtain the first modified powder;

[0017] S2. Add nanocellulose to the first modified powder and stir to mix to obtain the second modified powder;

[0018] S3. The second modified powder, polypropylene and polystyrene are placed in a rotor mixer and mixed to obtain a pellet.

[0019] S4. Place the granulated material in a co-rotating parallel twin-screw extruder for extrusion and granulation to obtain plastic masterbatch;

[0020] The amount of polypropylene used is 7% to 18% of the mass of the second modified powder, and the amount of polystyrene used is 5% to 15% of the mass of the second modified powder.

[0021] The present invention provides a method for preparing plastic masterbatch using light calcium carbonate as the main filler. This method is easy to control, not only improving the dispersibility of light calcium carbonate in the plastic masterbatch but also enhancing its biodegradability. Furthermore, it improves the mechanical properties and plasticity of the composite material. On the other hand, it effectively blocks oxygen and water vapor, better preventing the aging of plastic products and improving overall environmental friendliness.

[0022] As a preferred embodiment of this technical solution, step S1 specifically includes: adding light calcium carbonate and superdispersant SP-830 into a high-speed mixer for the first stirring; then adding polydimethylsiloxane, α-olefin sulfonate and alkyl polysaccharide into the high-speed mixer for the second stirring to obtain the first modified powder.

[0023] In the preparation of the first modified powder, firstly, light calcium carbonate and superdispersant SP-830 are placed in a high-speed mixer and stirred thoroughly. The superdispersant SP-830 is adsorbed on the surface of light calcium carbonate to fully improve the dispersion effect of light calcium carbonate. Then, polydimethylsiloxane, α-olefin sulfonate and alkyl polysaccharide are added to the high-speed mixer for secondary stirring to coat the surface of light calcium carbonate through physical adsorption, thereby improving its wettability and dispersibility. The first modified powder prepared in this way can significantly improve the dispersibility and compatibility of light calcium carbonate in polymers.

[0024] As a preferred embodiment of this technical solution, in step S1, during the first stirring, the speed of the high-speed mixer is controlled to be 1000~1400 rpm / min, and the mixture is stirred at 80~110℃ for 10~25 min;

[0025] During the second stirring, the speed of the high-speed mixer is controlled at 500~1000 rpm / min, and the mixture is stirred at 80~90℃ for 5~25 minutes.

[0026] In a preferred embodiment of this technical solution, in step S2, the nanocellulose is added to the first modified powder in multiple uniform additions.

[0027] Nanocellulose, due to its high specific surface area and excellent mechanical properties, can play a reinforcing role in modified powders. Multiple, uniform additions ensure the uniform distribution of nanocellulose in the powder, reducing its agglomeration and maximizing its reinforcing effect.

[0028] In a preferred embodiment of this technical solution, during step S2, the stirring speed of the mixer is controlled at 10-35 rpm / min, and stirring is performed at 60-120℃ for 20-100 minutes. The mixer is preferably a U-shaped drum mixer. When the stirring shaft of the U-shaped drum mixer starts to rotate, the inner and outer double-layer spiral ribbons on the shaft begin to work. The main function of the inner spiral ribbon is to move the material to both sides, while the outer spiral ribbon moves the material from both sides inwards. Through the synergistic effect of the inner and outer spiral ribbons, the material is mixed back and forth inside the mixer. Simultaneously, driven by the spiral ribbons, the material moves not only along the axial direction of the mixer but also along the radial direction, forming a convection circulation. Therefore, using a U-shaped drum mixer allows the material to achieve uniform mixing in a shorter time.

[0029] As a preferred embodiment of this technical solution, in step S3, during the internal mixing process, the temperature of the rotor internal mixer is controlled to be 120~200℃, the pressure to be 0.6~0.7MPa, and the mixing time to be 15~25min.

[0030] As a preferred embodiment of this technical solution, in step S4, using a co-rotating parallel twin-screw extruder during extrusion granulation is more conducive to material mixing, compounding, and granulation. Specifically, the temperature of the co-rotating parallel twin-screw extruder can be controlled at 160~250℃.

[0031] As a preferred embodiment of this technical solution, the particle size range of the plastic masterbatch prepared by the present invention is 0.1~3mm.

[0032] The plastic masterbatch and its preparation method of the present invention have at least the following beneficial effects:

[0033] The plastic masterbatch of this invention uses light calcium carbonate as the main filler, and activates and modifies the light calcium carbonate with a release agent / lubricant polydimethylsiloxane, an antistatic agent / emulsifier α-olefin sulfonate, an emulsifier / dispersant alkyl polysaccharide glycoside, a superdispersant SP-830, and nanocellulose to impart excellent processing fluidity, self-dispersibility, mechanical properties, anti-aging properties, and biodegradability. Plastic materials using polypropylene and polystyrene as plastic masterbatches can further improve the transparency of the plastic masterbatch, enhance its ability to block oxygen and water vapor, lower the melting temperature of the plastic masterbatch, and improve the fluidity of the melt, making it easier to mold and process to obtain lightweight, high-strength, stable, and impact-resistant biodegradable plastic masterbatches.

[0034] The method for preparing plastic masterbatch of this invention, through mixing, internal mixing, and granulation using optimized equipment, effectively improves the problem of poor dispersibility of light calcium carbonate in plastic masterbatch, thus avoiding inconsistent quality in downstream plastic products. Simultaneously, by optimizing the masterbatch formulation, the plastic masterbatch not only enhances mechanical properties but also becomes more biodegradable and environmentally friendly. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a flowchart of the preparation method of the plastic masterbatch of the present invention. Detailed Implementation

[0037] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0038] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] In the following examples, the particle size of the light calcium carbonate is 1 μm, and the calcium carbonate content is 98%.

[0041] Example 1

[0042] 50 parts of light calcium carbonate and 0.93 parts of superdispersant SP-830 were added to a high-speed mixer and stirred at 90°C and 1200 r / min for 12 min. Then, 0.3 parts of polydimethylsiloxane, 0.15 parts of α-olefin sulfonate and 0.1 parts of alkyl polyglycoside were added to the high-speed mixer and stirred at 85°C and 1000 r / min for 10 min to obtain the first modified powder.

[0043] The first modified powder was placed in a U-shaped barrel mixer, and nanocellulose was added at a mass of 5% of the first modified powder. The mixture was stirred at 75°C and 15 r / min for 30 min to obtain the second modified powder.

[0044] The second modified powder, 9% by mass of polypropylene random copolymer and 7% by mass of high-impact polystyrene were fed into a rotor mixer and mixed at 120°C and 0.6 MPa for 15 min to obtain a pellet.

[0045] While still hot, the granules are fed into a co-rotating parallel twin-screw extruder and extruded at 165°C to obtain lightweight calcium carbonate plastic masterbatch.

[0046] Example 2

[0047] 58 parts of light calcium carbonate and 0.76 parts of superdispersant SP-830 were added to a high-speed mixer and stirred at 95°C and 1100 r / min for 18 min. Then, 0.5 parts of polydimethylsiloxane, 0.2 parts of α-olefin sulfonate and 0.15 parts of alkyl polyglycoside were added to the high-speed mixer and stirred at 85°C and 1000 r / min for 10 min to obtain the first modified powder.

[0048] The first modified powder was placed in a U-shaped barrel mixer, and nanocellulose was added at 7% of the mass of the first modified powder. The mixture was stirred at 70°C and 20 r / min for 40 min to obtain the second modified powder.

[0049] The second modified powder, 12% by mass of polypropylene random copolymer and 9% by mass of high-impact polystyrene were fed into a rotor mixer and mixed at 150°C and 0.6 MPa for 18 minutes to obtain a pellet.

[0050] While still hot, the granules are fed into a co-rotating parallel twin-screw extruder and extruded at 185°C to obtain lightweight calcium carbonate plastic masterbatch.

[0051] Example 3

[0052] 66 parts of light calcium carbonate powder and 0.88 parts of superdispersant SP-830 were added to a high-speed mixer and stirred at 85°C and 1300 r / min for 20 min. Then, 0.4 parts of polydimethylsiloxane, 0.1 parts of α-olefin sulfonate and 0.2 parts of alkyl polyglycoside were added to the high-speed mixer and stirred at 85°C and 1000 r / min for 10 min to obtain the first modified powder.

[0053] The first modified powder was placed in a U-shaped barrel mixer, and nanocellulose was added at a mass of 3% of the first modified powder. The mixture was then mixed at 80°C and 25 r / min for 50 min to obtain the second modified powder.

[0054] The second modified powder, 11% of the mass of the second modified powder, and 12% of the mass of the second modified powder, were fed into a rotor mixer and mixed at 140°C and 0.65 MPa for 20 minutes to obtain a pellet.

[0055] While still hot, the granules are fed into a co-rotating parallel twin-screw extruder and extruded at 205°C to obtain lightweight calcium carbonate plastic masterbatch.

[0056] Example 4

[0057] 79 parts of light calcium carbonate powder and 1.2 parts of superdispersant SP-830 were added to a high-speed mixer and stirred at 100℃ and 1250 r / min for 22 min. Then, 0.8 parts of polydimethylsiloxane, 0.3 parts of α-olefin sulfonate and 0.2 parts of alkyl polyglycoside were added to the high-speed mixer and stirred at 85℃ and 1000 r / min for 10 min to obtain the first modified powder.

[0058] The first modified powder was placed in a U-shaped mixer, and nanocellulose (10% by mass of the first modified powder) was added. The mixture was then stirred at 60°C and 10 r / min for 80 min to obtain the second modified powder.

[0059] The second modified powder, 15% by mass of polypropylene random copolymer and 10% by mass of high-impact polystyrene were fed into a rotor mixer and mixed at 170°C and 0.7 MPa for 15 minutes to obtain a pellet.

[0060] While still hot, the granules are fed into a co-rotating parallel twin-screw extruder and extruded at 225°C to obtain lightweight calcium carbonate plastic masterbatch.

[0061] Example 5

[0062] 87 parts of light calcium carbonate powder and 1.67 parts of superdispersant SP-830 were added to a high-speed mixer and stirred at 105℃ and 1350 r / min for 16 min. Then, 0.7 parts of polydimethylsiloxane, 0.1 parts of α-olefin sulfonate and 0.3 parts of alkyl polyglycoside were added to the high-speed mixer and stirred at 85℃ and 1000 r / min for 10 min to obtain the first modified powder.

[0063] The first modified powder was placed in a U-shaped barrel mixer, and nanocellulose of 13% of the mass of the first modified powder was added. The mixture was then mixed at 105℃ and 10r / min for 80min to obtain the second modified powder.

[0064] The second modified powder, 16% by mass of polypropylene random copolymer and 6% by mass of high-impact polystyrene were fed into a rotor mixer and mixed at 200°C and 0.7 MPa for 25 minutes to obtain a pellet.

[0065] While still hot, the granules are fed into a co-rotating parallel twin-screw extruder and extruded at 245°C to obtain lightweight calcium carbonate plastic masterbatch.

[0066] Compare with Example 1

[0067] This comparative example is basically the same as Example 5, except that light calcium carbonate is replaced with heavy calcium carbonate.

[0068] Compare with Example 2

[0069] This comparative example is basically the same as Example 5, except that the superdispersant SP-830 is replaced with oxidized polyethylene wax.

[0070] Compare with Example 3

[0071] This comparative example is basically the same as Example 5, except that nanocellulose is replaced with nanosilica.

[0072] Compare with Example 4

[0073] This comparative example is basically the same as Example 5, except that: after the light calcium carbonate, polydimethylsiloxane, α-olefin sulfonate, alkyl polyglycoside, nanocellulose, random copolymer of polypropylene and high-impact polystyrene are mixed evenly, they are put into an internal mixer.

[0074] Compare with Example 5

[0075] This comparative example is basically the same as Example 5, except that: α-olefin sulfonate is replaced with alkyl amino acid, polydimethylsiloxane is replaced with polyether-modified polydimethylsiloxane, and alkyl polyglycoside is replaced with glyceryl monostearate.

[0076] Compare with Example 6

[0077] This comparative example is basically the same as Example 5, except that the "U"-shaped bucket mixer is replaced with a regular mixer.

[0078] Compare with Example 7

[0079] This comparative example is basically the same as Example 5, except that the high-impact polystyrene is replaced with α-methylstyrene oligomer M-80.

[0080] Compare with Example 8

[0081] 87 parts of heavy calcium carbonate, 0.1 parts of octadecyl phosphate, 0.3 parts of alkyl polysaccharide, 1.2 parts of aluminate coupling agent, 3 parts of nano silica, 3 parts of polypropylene random copolymer, and 1.5 parts of α-methylstyrene oligomer M-80 were mixed evenly and then fed into an internal mixer. After mixing at 200°C for 20 minutes, the mixture was transferred to a twin-screw extruder while still hot and extruded at 200°C to obtain heavy calcium carbonate plastic masterbatch.

[0082] Figure 1 This is a flowchart of the preparation method of the plastic masterbatch of the present invention.

[0083] Table 1 shows the performance test results of the plastic masterbatches prepared in Examples 1-5 and Comparative Examples 1-8.

[0084] Table 1. Performance test results of plastic masterbatch

[0085]

[0086] As shown in Table 1, the plastic masterbatches prepared in Examples 1-5 of this invention exhibit superior mechanical properties and anti-aging properties compared to Control Examples 1-8, and are more easily degraded, making them more environmentally friendly. This solves the problem in the prior art where the dispersion of light calcium carbonate in plastic masterbatches is poor, resulting in poor mechanical properties and difficulty in degradation of the prepared plastic masterbatches.

[0087] In Comparative Example 1, light calcium carbonate was replaced with heavy calcium carbonate. Although the modified system remained unchanged, the dispersibility was poor due to the high bulk density of heavy calcium carbonate.

[0088] In Comparative Example 2, the superdispersant SP-830 was replaced with oxidized polyethylene wax. Although oxidized polyethylene wax dispersant has a certain dispersing effect on light calcium carbonate, it still needs to be further improved.

[0089] In Comparative Example 3, nanocellulose was replaced with nano-silica. Although nano-silica can improve the strength, toughness, and anti-aging properties of plastic masterbatches, its effect may be limited by dispersibility and compatibility issues. Therefore, nanocellulose exhibits superior performance in comparison.

[0090] In Comparative Example 4, a plastic masterbatch was prepared by mixing light calcium carbonate, polydimethylsiloxane, α-olefin sulfonate, alkyl polysaccharide, nanocellulose, random copolymer of polypropylene, and high-impact polystyrene. Although the modified system was the same as in Example 5, the different mixing order and method resulted in the modified system not fully imparting excellent processing fluidity, self-dispersibility, mechanical properties, anti-aging properties, and biodegradability to light calcium carbonate.

[0091] In Comparative Example 5, α-olefin sulfonate was replaced with alkyl amino acids, polydimethylsiloxane was replaced with polyether-modified polydimethylsiloxane, and alkyl polysaccharide was replaced with glyceryl stearate. Due to reduced compatibility and instability of properties with environmental changes, the foaming properties, compatibility, and emulsification stability of the modified system decreased.

[0092] In Comparative Example 6, replacing the "U"-shaped drum mixer with a regular mixer, although the materials can be mixed to a certain extent, the mechanical properties, anti-aging properties, and biodegradability of the prepared plastic masterbatch are still limited to some extent.

[0093] In Comparative Example 7, high-impact polystyrene was replaced with α-methylstyrene oligomer M-80. Although M-80 has excellent flowability, light aging resistance and thermal stability, as well as good electrical insulation, as an oligomer, its tensile properties are slightly inferior to those of high-impact polystyrene.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A plastic masterbatch, characterized in that, The raw materials include the following parts by weight: 46-93 parts of light calcium carbonate, 0.1-0.8 parts of polydimethylsiloxane, 0.1-0.3 parts of α-olefin sulfonate, 0.1-0.3 parts of alkyl polysaccharide, 0.7-1.8 parts of superdispersant SP-830, and 0.5-15 parts of nanocellulose; The plastic masterbatch contains polypropylene and polystyrene. The method for preparing the plastic masterbatch includes the following steps: S1. Light calcium carbonate, polydimethylsiloxane, α-olefin sulfonate, alkyl polysaccharide and superdispersant SP-830 are put into a high-speed mixer and mixed to obtain the first modified powder; S2. Add nanocellulose to the first modified powder and stir to mix to obtain the second modified powder; S3. The second modified powder, polypropylene and polystyrene are placed in a rotor mixer and mixed to obtain a pellet. S4. Place the granulated material in a co-rotating parallel twin-screw extruder for extrusion and granulation to obtain plastic masterbatch; The amount of polypropylene used is 7% to 18% of the mass of the second modified powder, and the amount of polystyrene used is 5% to 15% of the mass of the second modified powder.

2. The plastic masterbatch according to claim 1, characterized in that, The light calcium carbonate has a particle size of <5μm and a calcium carbonate content of >95%.

3. The plastic masterbatch according to claim 1, characterized in that, The polypropylene is a random copolymer of polypropylene, and the polystyrene is high-impact polystyrene.

4. The plastic masterbatch according to claim 1, characterized in that, Step S1 specifically includes: adding light calcium carbonate and superdispersant SP-830 into a high-speed mixer for the first stirring; then adding polydimethylsiloxane, α-olefin sulfonate and alkyl polysaccharide into the high-speed mixer for the second stirring to obtain the first modified powder.

5. The plastic masterbatch according to claim 4, characterized in that, In step S1, during the first stirring, the speed of the high-speed mixer is controlled at 1000~1400 rpm / min, and the mixture is stirred at 80~110℃ for 10~25 min; During the second stirring, the speed of the high-speed mixer is controlled at 500~1000 rpm / min, and the mixture is stirred at 80~90℃ for 5~25 minutes.

6. The plastic masterbatch according to claim 1, characterized in that, In step S2, the nanocellulose is added to the first modified powder in multiple uniform additions.

7. The plastic masterbatch according to claim 1, characterized in that, In step S2, during the stirring process, the speed of the mixer is controlled at 10~35 rpm / min, and the mixture is stirred at 60~120℃ for 20~100 min.

8. The plastic masterbatch according to claim 1, characterized in that, In step S3, during the internal mixing process, the temperature of the rotor internal mixer is controlled at 120~200℃, the pressure at 0.6~0.7MPa, and the mixing time at 15~25min.

9. The plastic masterbatch according to claim 1, characterized in that, In step S4, during the extrusion granulation, the temperature of the co-rotating parallel twin-screw extruder is controlled at 160~250℃.

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