A composite additive for improving the foaming properties of recycled polystyrene.

Abstract

This invention discloses a composite additive for repairing the foaming properties of recycled polystyrene, relating to the field of recycled polystyrene. It comprises: 30-50 parts of a matrix repair component, 20-35 parts of a nucleating-reinforcing composite component, 10-20 parts of an antibacterial and flame-retardant composite component, and 5-10 parts of a dispersant. Modified rosin ester and polybutadiene oligomers are used as the matrix repair component, combined with nano-calcium carbonate and talc as the nucleating-reinforcing composite component, and further combined with phytic acid and quaternized chitosan functional components and zinc stearate dispersant to form a stable composite system. This system imparts antibacterial and flame-retardant properties to the product, solving the problem of single-function traditional additives, significantly improving the quality of recycled material products, realizing high-value utilization of recycled materials, and simultaneously repairing damaged molecular chains in recycled materials, improving processing flowability and cell nucleation effect, thus compensating for the deficiency of reduced foaming performance in recycled polystyrene.

Description

Technical Field

[0001] This invention relates to the field of polystyrene recycled materials technology, and specifically to a composite additive for repairing the foaming properties of polystyrene recycled materials. Background Technology

[0002] Polystyrene (PS) is widely used in packaging, building insulation, and electronics due to its lightweight, excellent insulation, superior mechanical properties, and low cost. This results in a massive amount of polystyrene waste. Recycled polystyrene refers to plastic raw materials obtained from waste polystyrene plastic through recycling, sorting, washing, crushing, and melt granulation processes, making them suitable for reuse in production.

[0003] However, during the recycling, crushing, and melting processes of recycled polystyrene, its polymer chains break and cross-link due to factors such as thermo-oxidative aging and mechanical shearing, resulting in a wider molecular weight distribution and irreversible and severe degradation of its foaming properties. Currently, the restoration of the foaming properties of recycled polystyrene mostly employs single plasticizers or simple compound systems. While these methods can improve flowability to some extent, they generally focus on a single function, limiting the use of the restored products to low-end applications and hindering their transformation into high-value products.

[0004] Therefore, the present invention provides a composite additive for repairing the foaming performance of recycled polystyrene material. On the basis of efficiently repairing the molecular chain and cell structure of recycled polystyrene material and significantly improving the foaming ratio and uniformity, it endows the product with antibacterial and flame retardant functions. Summary of the Invention

[0005] The purpose of this invention is to provide a composite additive for repairing the foaming performance of recycled polystyrene materials, thereby solving the problem of limited functionality in existing composite additives.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a composite additive for repairing the foaming properties of recycled polystyrene, comprising the following components by mass parts:

[0007] 30-50 parts of matrix repair component, 20-35 parts of nucleation-reinforcing composite component, 10-20 parts of antibacterial and flame-retardant composite component, and 5-10 parts of dispersant;

[0008] The matrix repair component is a compound of modified rosin ester and polybutadiene oligomer;

[0009] The nucleating-reinforcing composite component is a mixture of nano-calcium carbonate and talc.

[0010] The antibacterial and flame-retardant composite component is a compound of phytic acid and quaternized chitosan;

[0011] The dispersant is zinc stearate.

[0012] Furthermore, the mass ratio of the modified rosin ester to the polybutadiene oligomer is 2-3:1.

[0013] Furthermore, the modified rosin ester is a maleic anhydride modified rosin ester with an acid value of 80-95 mgKOH / g and a softening point of 85-95℃;

[0014] The number-average molecular weight of the polybutadiene oligomer is 1000-2000.

[0015] Furthermore, the mass ratio of the nano-calcium carbonate to talc is 1:1-2.

[0016] Furthermore, the particle size of the nano-calcium carbonate is 50-100 nm, and the particle size of the talc is 1-5 μm.

[0017] Furthermore, the mass ratio of phytic acid to quaternized chitosan is 3-4:1;

[0018] The phytic acid has a purity of ≥98%, and the degree of substitution of the quaternized chitosan is 60%-70%.

[0019] Furthermore, the particle size of the composite additive is 100-200 mesh.

[0020] A method for preparing a composite additive for improving the foaming properties of recycled polystyrene includes the following steps:

[0021] S1. Weigh out the matrix repair component, nucleating-reinforcing composite component, antibacterial flame retardant composite component and dispersant according to the formula ratio, and set aside;

[0022] S2. Add the matrix repair components to the mixer, heat to 80-90℃, and stir for 10-15 minutes until completely melted;

[0023] S3. Add the nucleating-reinforcing composite component and the antibacterial flame retardant composite component to the molten system in sequence, maintain the temperature at 80-90℃, and stir for 20-30 minutes to ensure that the components are evenly dispersed.

[0024] S4. Add dispersant, continue stirring for 10-15 minutes, cool to room temperature, pulverize, and obtain composite additive.

[0025] Compared with existing technologies, this invention provides a composite additive for repairing the foaming performance of recycled polystyrene. It uses modified rosin ester and polybutadiene oligomers as the matrix repair components, compounded with nano-calcium carbonate and talc as nucleating-reinforcing composite components, and combined with phytic acid and quaternized chitosan functional components and zinc stearate dispersant to form a stable composite system. This system imparts antibacterial and flame-retardant properties to the product, solving the problem of single-function traditional additives, significantly improving the quality of recycled material products, realizing high-value utilization of recycled materials, and simultaneously repairing damaged molecular chains in recycled materials, improving processing fluidity and cell nucleation effect, thus compensating for the deficiency of reduced foaming performance in recycled polystyrene. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below.

[0027] Example 1:

[0028] This embodiment provides a composite additive for repairing the foaming properties of recycled polystyrene. The components are as follows by mass: 30 parts matrix repair component (20 parts maleic anhydride modified rosin ester, 10 parts polybutadiene oligomer), 20 parts nucleating-reinforcing composite component (8 parts nano calcium carbonate, 12 parts talc), 10 parts antibacterial and flame retardant composite component (7.5 parts phytic acid, 2.5 parts quaternized chitosan), and 5 parts dispersant (zinc stearate).

[0029] The maleic anhydride-modified rosin ester has an acid value of 85 mg KOH / g and a softening point of 88℃; the number-average molecular weight of the polybutadiene oligomer is 1500; the particle size of the nano-calcium carbonate is 60 nm, and the particle size of the talc is 2 μm; the purity of phytic acid is ≥98%, and the degree of substitution of quaternized chitosan is 65%.

[0030] Maleic anhydride-modified rosin ester has good compatibility and plasticizing properties. It can penetrate into the gaps between the molecular chains of recycled polystyrene, weaken the intermolecular forces, repair broken molecular chains, and improve the flowability of the recycled material. Polybutadiene oligomers have flexible molecular chains that can entangle with polystyrene molecular chains, enhance the toughness of the molecular chains, and reduce the rupture of cell walls during foaming. The combination of the two forms a synergistic effect, comprehensively repairing the foaming performance of the recycled material, which helps to solve the problem of limited effect of single repair components.

[0031] Nano-calcium carbonate, as a nucleating agent, can provide a large number of uniform nucleation sites during the foaming process, refine the pores, and improve the uniformity of the pores. Talc, as a reinforcing agent, can enhance the mechanical properties of foamed products, while improving the dispersibility of composite additives in recycled materials. It works synergistically with the matrix repair components to further enhance the foaming repair effect.

[0032] Phytic acid possesses excellent flame-retardant properties; its phosphate groups can form a char layer at high temperatures, preventing heat transfer and oxygen entry, thus imparting a flame-retardant effect to foamed products. Quaternized chitosan exhibits superior antibacterial properties; its quaternary ammonium groups can disrupt bacterial cell membranes, inhibiting bacterial reproduction and providing antibacterial effects to foamed products. The compound of phytic acid and quaternized chitosan not only imparts antibacterial and flame-retardant properties to foamed products but also synergistically enhances the foaming and repairing effect with matrix repair components and nucleating-reinforcing composite components. Zinc stearate improves the dispersibility of each component, prevents component aggregation, enhances the compatibility of composite additives with recycled polystyrene materials, and prevents problems such as stratification and precipitation during processing.

[0033] This embodiment also provides a method for preparing a composite additive for repairing the foaming properties of recycled polystyrene, comprising the following steps:

[0034] (1) Weigh the matrix repair component, nucleation-reinforcing composite component, antibacterial flame retardant composite component and dispersant according to the formula ratio, and set aside;

[0035] (2) Add the matrix repair component to the mixer, heat to 80°C, and stir for 15 minutes until completely melted;

[0036] (3) Add the nucleating-reinforcing composite component and the antibacterial flame retardant composite component to the molten system in sequence, keep the temperature at 80℃, stir for 30 minutes, and make the components evenly dispersed;

[0037] (4) Add dispersant, continue stirring for 15 minutes, cool to room temperature, and pulverize to a particle size of 100 mesh to obtain composite additive.

[0038] Adding composite additives at 3% of the mass of recycled polystyrene to the recycled material, mixing thoroughly, and then foaming using a conventional extrusion foaming process at 150℃ and 0.3MPa can restore the foaming properties of the recycled polystyrene and simultaneously impart antibacterial and flame-retardant properties to the foamed products. The recycled polystyrene is obtained by washing, crushing, and drying waste polystyrene foam and polystyrene plastic fragments into recycled granules, with a melt flow rate of 1.5-3.0 g / 10 min (200℃, 5 kg).

[0039] Example 2:

[0040] This embodiment is basically the same as Embodiment 1, except that: 40 parts of matrix repair component (28 parts of maleic anhydride modified rosin ester, 12 parts of polybutadiene oligomer), 28 parts of nucleating-reinforcing composite component (10 parts of nano-calcium carbonate, 18 parts of talc), 15 parts of antibacterial and flame-retardant composite component (11.25 parts of phytic acid, 3.75 parts of quaternized chitosan), and 8 parts of dispersant (zinc stearate). The maleic anhydride modified rosin ester has an acid value of 90 mg KOH / g and a softening point of 90℃; the polybutadiene oligomer has a number-average molecular weight of 1800; the nano-calcium carbonate has a particle size of 80 nm, and the talc has a particle size of 3 μm; the phytic acid purity is ≥98%, and the quaternized chitosan has a substitution degree of 68%.

[0041] The preparation method includes the following steps:

[0042] (1) Weigh each component according to the proportions and set aside;

[0043] (2) Add the matrix repair component to the mixer, heat to 85°C, and stir for 12 minutes until completely melted;

[0044] (3) Add the nucleating-reinforcing composite component and the antibacterial flame retardant composite component to the molten system in sequence, maintain the temperature at 85℃, stir for 25 minutes, and make the components evenly dispersed;

[0045] (4) Add dispersant, continue stirring for 12 minutes, cool to room temperature, and pulverize to a particle size of 150 mesh to obtain composite additive.

[0046] The composite additives were added to the recycled polystyrene material at 5% of the material's mass. After mixing evenly, the material was foamed using an extrusion foaming process at 165℃ and 0.4MPa to obtain the foamed product.

[0047] Example 3:

[0048] This embodiment is basically the same as Embodiment 1, except that: 50 parts of matrix repair component (37.5 parts of maleic anhydride modified rosin ester, 12.5 parts of polybutadiene oligomer), 35 parts of nucleating-reinforcing composite component (12 parts of nano-calcium carbonate, 23 parts of talc), 20 parts of antibacterial and flame-retardant composite component (16 parts of phytic acid, 4 parts of quaternized chitosan), and 10 parts of dispersant (zinc stearate). The acid value of maleic anhydride modified rosin ester is 95 mg KOH / g, and the softening point is 95℃; the number-average molecular weight of polybutadiene oligomer is 1900; the particle size of nano-calcium carbonate is 90 nm, and the particle size of talc is 4 μm; the purity of phytic acid is ≥98%, and the degree of substitution of quaternized chitosan is 69%.

[0049] The preparation method includes the following steps:

[0050] (1) Weigh each component according to the proportions and set aside;

[0051] (2) Add the matrix repair component to the mixer, heat to 90°C, and stir for 10 minutes until completely melted;

[0052] (3) Add the nucleating-reinforcing composite component and the antibacterial flame retardant composite component to the molten system in sequence, keep the temperature at 90℃, stir for 20 minutes, and make the components evenly dispersed;

[0053] (4) Add dispersant, continue stirring for 10 minutes, cool to room temperature, and pulverize to a particle size of 200 mesh to obtain composite additive.

[0054] The composite additives were added to the recycled polystyrene material at 8% of the material's mass. After mixing evenly, the material was foamed at 180℃ and 0.5MPa using an extrusion foaming process to obtain the foamed product.

[0055] Example 4:

[0056] This embodiment is basically the same as Embodiment 1, except that: 35 parts of matrix repair component (25 parts of maleic anhydride modified rosin ester, 10 parts of polybutadiene oligomer), 24 parts of nucleating-reinforcing composite component (9 parts of nano-calcium carbonate, 15 parts of talc), 12 parts of antibacterial and flame-retardant composite component (9 parts of phytic acid, 3 parts of quaternized chitosan), and 6 parts of dispersant (zinc stearate). The maleic anhydride modified rosin ester has an acid value of 85 mg KOH / g and a softening point of 88℃; the polybutadiene oligomer has a number-average molecular weight of 1500; the nano-calcium carbonate has a particle size of 60 nm, and the talc has a particle size of 2 μm; the phytic acid purity is ≥98%, and the quaternized chitosan has a substitution degree of 65%.

[0057] The preparation method includes the following steps:

[0058] (1) Weigh the matrix repair component, nucleation-reinforcing composite component, antibacterial flame retardant composite component and dispersant according to the formula ratio, and set aside;

[0059] (2) Add the matrix repair component to the mixer, heat to 82°C, and stir for 13 minutes until completely melted;

[0060] (3) Add the nucleating-reinforcing composite component and the antibacterial flame retardant composite component to the molten system in sequence, maintain the temperature at 82℃, stir for 27 min, and make the components evenly dispersed;

[0061] (4) Add dispersant, continue stirring for 13 minutes, cool to room temperature, and pulverize to a particle size of 120 mesh to obtain composite additive.

[0062] The composite additive was added to the recycled polystyrene material at 4% of the material's mass. After thorough mixing, the mixture was foamed using a conventional extrusion foaming process at 155℃ and 0.35MPa. The recycled polystyrene material consisted of recycled granules obtained from waste polystyrene foam and polystyrene plastic fragments after washing, crushing, and drying, with a melt flow rate of 1.5-3.0 g / 10 min (200℃, 5 kg).

[0063] Example 5:

[0064] This embodiment is basically the same as Example 1, except that: 42 parts of matrix repair component (30 parts of maleic anhydride modified rosin ester, 12 parts of polybutadiene oligomer), 30 parts of nucleating-reinforcing composite component (11 parts of nano-calcium carbonate, 19 parts of talc), 16 parts of antibacterial and flame-retardant composite component (12.5 parts of phytic acid, 3.5 parts of quaternized chitosan), and 7 parts of dispersant (zinc stearate). The maleic anhydride modified rosin ester has an acid value of 90 mg KOH / g and a softening point of 90℃; the polybutadiene oligomer has a number-average molecular weight of 1800; the nano-calcium carbonate has a particle size of 80 nm, and the talc has a particle size of 3 μm; the phytic acid purity is ≥98%, and the quaternized chitosan has a substitution degree of 68%.

[0065] The preparation method includes the following steps: (1) Weigh the matrix repair component, nucleating-reinforcing composite component, antibacterial flame retardant composite component and dispersant according to the ratio, and set aside; (2) Add the matrix repair component to the mixer, heat to 86°C, and stir for 11 min until completely melted; (3) Add the nucleating-reinforcing composite component and antibacterial flame retardant composite component to the melt system in sequence, keep the temperature at 86°C, stir for 23 min, and make each component evenly dispersed; (4) Add the dispersant, continue stirring for 11 min, cool to room temperature, and pulverize to a particle size of 160 mesh to obtain the composite additive.

[0066] Adding a composite additive at 6% of the mass of the recycled polystyrene material to the recycled material, mixing thoroughly, and then foaming using a conventional extrusion foaming process at 170℃ and 0.42MPa can restore the foaming properties of the recycled polystyrene material and simultaneously impart antibacterial and flame-retardant properties to the foamed products. The recycled polystyrene material is recycled granules obtained from waste polystyrene foam and polystyrene plastic fragments after washing, crushing, and drying, with a melt flow rate of 1.5-3.0 g / 10min (200℃, 5 kg).

[0067] Example 6:

[0068] This embodiment is basically the same as Embodiment 1, except that: 48 parts of matrix repair component (36 parts of maleic anhydride modified rosin ester, 12 parts of polybutadiene oligomer), 32 parts of nucleating-reinforcing composite component (11.5 parts of nano-calcium carbonate, 20.5 parts of talc), 18 parts of antibacterial and flame-retardant composite component (14.2 parts of phytic acid, 3.8 parts of quaternized chitosan), and 9 parts of dispersant (zinc stearate). The acid value of maleic anhydride modified rosin ester is 95 mg KOH / g, and the softening point is 93℃; the number average molecular weight of polybutadiene oligomer is 2000; the particle size of nano-calcium carbonate is 100 nm, and the particle size of talc is 5 μm; the purity of phytic acid is ≥98%, and the degree of substitution of quaternized chitosan is 70%.

[0069] The preparation method includes the following steps: (1) Weigh the matrix repair component, nucleating-reinforcing composite component, antibacterial flame retardant composite component and dispersant according to the ratio, and set aside; (2) Add the matrix repair component to the mixer, heat to 88°C, and stir for 10 min until completely melted; (3) Add the nucleating-reinforcing composite component and antibacterial flame retardant composite component to the melt system in sequence, keep the temperature at 88°C, stir for 21 min, and make each component evenly dispersed; (4) Add the dispersant, continue stirring for 10 min, cool to room temperature, and pulverize to a particle size of 180 mesh to obtain the composite additive.

[0070] The composite additive was added to the recycled polystyrene material at 7% of the material's mass. After thorough mixing, the mixture was foamed using a conventional extrusion foaming process at 175℃ and 0.48MPa. The recycled polystyrene material consisted of recycled granules obtained from waste polystyrene foam and polystyrene plastic fragments after washing, crushing, and drying, with a melt flow rate of 1.5-3.0 g / 10 min (200℃, 5 kg).

[0071] Example 7:

[0072] This embodiment is basically the same as Embodiment 1, except that: 32 parts of matrix repair component (22 parts of maleic anhydride modified rosin ester, 10 parts of polybutadiene oligomer), 22 parts of nucleating-reinforcing composite component (7.5 parts of nano-calcium carbonate, 14.5 parts of talc), 11 parts of antibacterial and flame-retardant composite component (8.2 parts of phytic acid, 2.8 parts of quaternized chitosan), and 5.5 parts of dispersant (zinc stearate). The acid value of maleic anhydride modified rosin ester is 80 mg KOH / g, and the softening point is 85℃; the number average molecular weight of polybutadiene oligomer is 1000; the particle size of nano-calcium carbonate is 50 nm, and the particle size of talc is 1.0 μm; the purity of phytic acid is ≥98%, and the degree of substitution of quaternized chitosan is 60%.

[0073] The preparation method includes the following steps: (1) Weigh the matrix repair component, nucleating-reinforcing composite component, antibacterial flame retardant composite component and dispersant according to the ratio, and set aside; (2) Add the matrix repair component to the mixer, heat to 81°C, and stir for 14 min until completely melted; (3) Add the nucleating-reinforcing composite component and antibacterial flame retardant composite component to the melt system in sequence, keep the temperature at 81°C, stir for 28 min, and make each component evenly dispersed; (4) Add the dispersant, continue stirring for 14 min, cool to room temperature, and pulverize to a particle size of 110 mesh to obtain the composite additive.

[0074] The composite additive was added to the recycled polystyrene material at 3.5% of its mass. After thorough mixing, the mixture was foamed using a conventional extrusion foaming process at 152℃ and 0.32MPa. The recycled polystyrene material consisted of recycled granules obtained from waste polystyrene foam and polystyrene plastic fragments after washing, crushing, and drying, with a melt flow rate of 1.5-3.0 g / 10 min (200℃, 5 kg).

[0075] Comparative Example 1:

[0076] This embodiment is basically the same as Embodiment 2, except that: 40 parts of matrix repair component (maleic anhydride modified rosin ester only), 28 parts of nucleation-reinforcing composite component (10 parts of nano calcium carbonate, 18 parts of talc), and 8 parts of dispersant (zinc stearate).

[0077] Comparative Example 2:

[0078] This embodiment is basically the same as Embodiment 2, except that: 40 parts of matrix repair component (24 parts of maleic anhydride modified rosin ester, 16 parts of polybutadiene oligomer), 28 parts of nucleating-reinforcing composite component (only nano calcium carbonate), 15 parts of antibacterial and flame retardant composite component (10.7 parts of phytic acid, 4.3 parts of quaternized chitosan), and 8 parts of dispersant (zinc stearate).

[0079] Comparative Example 3:

[0080] Commercially available general-purpose polystyrene recycled material foaming modification masterbatch (compliant with ASTM D4812 standard) was used. The recommended addition amount was 5% of the mass of the polystyrene recycled material, and foaming was carried out using the same extrusion foaming process (165℃, 0.4MPa) to obtain foamed products.

[0081] Example 4:

[0082] Performance tests were conducted on the foamed products of Examples 1 to 3 and Comparative Examples 1 to 3. The test items included: foaming ratio, cell diameter, cell pass rate, tensile strength, impact strength, antibacterial rate (Escherichia coli, Staphylococcus aureus), and flame retardant rating. The test results are shown in the table below:

[0083] Table 1 Performance Test Table for Foamed Products

[0084] Test sample Expansion ratio (times) Cell diameter (μm) Bubble quality rate (%) Tensile strength (MPa) Impact strength (kJ / m²) Antibacterial rate (%) Flame retardant rating Example 1 20 80-100 95 12.3 25.6 ≥99 UL94 V-0 Example 2 25 60-80 98 13.8 28.9 ≥99 UL94 V-0 Example 3 30 50-70 99 14.5 30.2 ≥99 UL94 V-0 Example 4 22 70-90 96 12.9 26.8 ≥99 UL94 V-0 Example 5 26 55-75 98 14.1 29.5 ≥99 UL94 V-0 Example 6 28 50-65 99 14.3 29.8 ≥99 UL94 V-0 Example 7 21 75-95 95 12.6 26.2 ≥99 UL94 V-0 Comparative Example 1 15 100-150 82 10.1 20.3 ≤50 UL94 V-2 Comparative Example 2 18 90-130 88 11.2 22.5 ≥99 UL94 V-0 Comparative Example 3 16 100-140 85 11.5 23.1 ≤60 UL94 V-1

[0085] Test Result Analysis:

[0086] As shown in Table 1, the foaming ratio and cell qualification rate of each embodiment are significantly higher than those of the comparative example, and the cell diameter is more uniform. This indicates that the combination of the matrix repair component and the nucleation-reinforcing composite component of the present invention can efficiently repair the foaming performance of recycled polystyrene material, which is far superior to single repair components and commercially available conventional polystyrene recycled material foaming aids. In terms of mechanical properties, the tensile strength and impact strength of each embodiment are higher than those of the comparative example, indicating that the synergistic effect of the components of the present invention can not only repair the foaming performance, but also improve the mechanical properties of the foamed products.

[0087] Regarding cross-domain functionality, the foamed products of each embodiment exhibit an antibacterial rate of ≥99% and a flame retardant rating of UL94 V-0. In contrast, Comparative Examples 1 and 3 show poor antibacterial and flame retardant properties, indicating that the addition of the antibacterial and flame retardant composite components of this invention can impart antibacterial and flame retardant effects to the foamed products. Comparing Example 2 with Comparative Example 2, it can be seen that the combination of nano-calcium carbonate and talc in the nucleating-reinforcing composite components can further enhance the foaming and repairing effect. The synergistic effect of single nano-calcium carbonate is limited, demonstrating the synergistic advantage of the component combination of this invention.

[0088] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above description is illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A composite co-agent for repairing the foaming property of polystyrene recycled material, characterized by, By mass parts, it includes the following components: 30-50 parts of matrix repair component, 20-35 parts of nucleation-reinforcing composite component, 10-20 parts of antibacterial and flame-retardant composite component, and 5-10 parts of dispersant; The matrix repair component is a compound of modified rosin ester and polybutadiene oligomer; The nucleating-reinforcing composite component is a mixture of nano-calcium carbonate and talc. The antibacterial and flame-retardant composite component is a compound of phytic acid and quaternized chitosan; The dispersant is zinc stearate.

2. The composite agent for repairing the foaming property of polystyrene recycled material according to claim 1, characterized in that, The mass ratio of the modified rosin ester to the polybutadiene oligomer is 2-3:

1.

3. The complex agent for repairing the foaming property of polystyrene recycled material according to claim 2, characterized in that, The modified rosin ester is a maleic anhydride modified rosin ester with an acid value of 80-95 mgKOH / g and a softening point of 85-95℃. The number-average molecular weight of the polybutadiene oligomer is 1000-2000.

4. The complex agent for repairing foaming performance of polystyrene recycled material according to claim 1, characterized in that, The mass ratio of the nano-calcium carbonate to talc is 1:1-2.

5. A composite additive for repairing the foaming properties of recycled polystyrene according to claim 4, characterized in that, The nano-calcium carbonate has a particle size of 50-100 nm, and the talc has a particle size of 1-5 μm.

6. The composite additive for repairing the foaming properties of recycled polystyrene according to claim 1, characterized in that, The mass ratio of phytic acid to quaternized chitosan is 3-4:1; The phytic acid has a purity of ≥98%, and the degree of substitution of the quaternized chitosan is 60%-70%.

7. The composite additive for repairing the foaming properties of recycled polystyrene according to claim 1, characterized in that, The particle size of the composite additive is 100-200 mesh.

8. A method for preparing a composite additive for repairing the foaming properties of recycled polystyrene, characterized in that, Includes the following steps: S1. Weigh out the matrix repair component, nucleating-reinforcing composite component, antibacterial flame retardant composite component and dispersant according to the formula ratio, and set aside; S2. Add the matrix repair components to the mixer, heat to 80-90℃, and stir for 10-15 minutes until completely melted; S3. Add the nucleating-reinforcing composite component and the antibacterial flame retardant composite component to the molten system in sequence, maintain the temperature at 80-90℃, and stir for 20-30 minutes to ensure that the components are evenly dispersed. S4. Add dispersant, continue stirring for 10-15 minutes, cool to room temperature, pulverize, and obtain composite additive.