Light aging resistant plastic for automotive upholstery and preparation method of light aging resistant plastic

Abstract

The invention relates to the technical field of chemical products, in particular to light aging resistant plastic for automotive upholstery and a preparation method thereof. The anti-aging plastic overcomes the problem of poor anti-aging performance of the plastic for the automotive upholstery. The preparation method comprises the following steps: chemically grafting p-aminodiphenylamine to the surface of lignin through a bonding substance of silane molecules to prepare an antioxidant; preparing a carbon quantum dot-polyacrylic acid core-shell structure from glucose and polyacrylic acid through an electrostatic spinning-post-treatment method; the preparation method comprises the following steps: mixing an antioxidant, HALS and polyethylene glycol, and carrying out ultrasonic treatment and spray drying to obtain an anti-yellowing agent; by controlling the mass ratio of the carbon quantum dot-polyacrylic acid core-shell structure and the anti-yellowing agent and changing the technological parameters during extrusion granulation, the anti-aging performance of the prepared illumination aging resistant plastic for the automotive interior trim parts is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of chemical products, in particular to a light aging resistant plastic for automobile interior decoration parts and a preparation method thereof. Background Art

[0002] With the rapid development of the global automotive industry and the continuous advancement of technology, consumers' requirements for the comfort, aesthetics and overall quality of the car's interior environment are constantly increasing. As an important part of the driving experience, the lasting beauty of the appearance, durability of the materials and safety of the automotive interior parts have become the focus of consumers. Although traditional plastic materials for automotive interior parts such as polypropylene, polyoxymethylene and acrylonitrile-butadiene-styrene copolymer are widely used due to their good processability, cost-effectiveness and certain mechanical strength, they also have certain limitations.

[0003] During daily driving and parking, the interior parts of cars are inevitably exposed to light for a long time, and suffer from the combined attack of ultraviolet radiation, heat and oxygen, which leads to molecular chain breakage, structural changes, and then causes aging and discoloration of materials. Aging not only affects the aesthetic appearance of automotive interior parts, but also causes a significant decline in the mechanical properties of materials, such as reduced toughness and increased brittleness, which directly affects the safety and service life of automotive interior parts. With global climate change and the increase in the intensity of ultraviolet radiation, this problem has become more prominent. It is particularly important to develop a plastic material for automotive interior parts that can effectively resist light aging and maintain long-term stability.

[0004] Therefore, a light aging resistant plastic for automobile interior parts and a preparation method thereof are proposed. Summary of the invention

[0005] The object of the present invention is to provide a light-resistant plastic for automobile interior parts and a preparation method thereof. The antioxidant is prepared by chemically grafting p-aminodiphenylamine onto the surface of lignin through a bond of a silane molecule; a carbon quantum dot-polyacrylic acid core-shell structure is prepared from glucose and polyacrylic acid through an electrostatic spinning-post-treatment method; an anti-yellowing agent is obtained by mixing, ultrasonicating and spray-drying the antioxidant, HALS and polyethylene glycol; and the anti-yellowing agent is obtained by controlling the mass ratio of the carbon quantum dot-polyacrylic acid core-shell structure and the anti-yellowing agent and changing the process parameters during extrusion granulation, so that the anti-aging performance of the light-resistant plastic for automobile interior parts is significantly improved.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing a light-resistant plastic for automotive interior parts, the preparation method being as follows: adding polypropylene and acrylonitrile-butadiene-styrene copolymer into a vacuum drying oven, drying at 80°C for 4 hours, adding into a high-speed stirrer, stirring at a speed of 800 r / min for 20 minutes, adding a carbon quantum dot-polyacrylic acid core-shell structure and an anti-yellowing agent, reducing the speed to 500 r / min, continuing stirring for 10-30 minutes, adding zinc stearate and stirring for 5 minutes, and extruding and granulating to obtain the light-resistant plastic for automotive interior parts;

[0008] The anti-yellowing agent is obtained by mixing, ultrasonicating and spray drying HALS, polyethylene glycol and antioxidant;

[0009] The antioxidant is obtained by reacting p-aminodiphenylamine, KH560 and lignin;

[0010] The carbon quantum dot-polyacrylic acid core-shell structure was prepared from glucose and polyacrylic acid by electrospinning-post-treatment method.

[0011] Preferably, the preparation method of the anti-yellowing agent is as follows: HALS and polyethylene glycol are added to a high-speed disperser, and stirred at a speed of 1000-1500 r / min for 10-20 min to obtain a dispersed system; an antioxidant is added to the dispersed system, the speed is reduced to 600-800 r / min, and stirring is continued for 5-15 min to obtain a mixed system; the mixed system is ultrasonically treated at a frequency of 20-40 kHz for 10-15 min and then spray-dried to obtain a powdered anti-yellowing agent; an LPG-5 spray dryer is selected for spray drying.

[0012] Preferably, the inlet air temperature of the spray drying is controlled at 180-200°C, and the outlet air temperature is 80-100°C.

[0013] Preferably, the preparation method of the antioxidant is as follows: dissolve p-aminodiphenylamine in toluene, stir at 80°C for 1 hour, add KH560, and continue stirring for 4.5 hours to obtain a mixed solution; dissolve lignin in an aqueous sodium hydroxide solution, adjust the pH to 10-12, and obtain an alkaline solution; add the alkaline solution to the mixed solution, heat to 110°C, and stir for 40 hours to obtain an antioxidant.

[0014] Preferably, the preparation method of the carbon quantum dot-polyacrylic acid core-shell structure is as follows: dissolve glucose in N, N-dimethylformamide, stir and dissolve, add polyacrylic acid, N, N-methylenebisacrylamide and azobisisobutyronitrile, and continue stirring for 30-50 minutes to obtain a spinning solution; load the spinning solution into a syringe, install it on an electrospinning device, the distance between the syringe needle and the receiving device is 12-18 cm, and electrospinning is performed under the conditions of a voltage of 10-18 kV and a spinning speed of 1 ml / h to obtain a composite fiber; move the composite fiber into a high-temperature furnace, perform high-temperature annealing treatment under a nitrogen atmosphere, and then vacuum dry to obtain a carbon quantum dot-polyacrylic acid core-shell structure; the high-temperature annealing treatment temperature is 850°C and the time is 2.5 hours; the electrospinning equipment is an all-in-one high-voltage electrospinning machine TL-OMNI.

[0015] Preferably, extrusion granulation is carried out by a twin-screw extruder; the temperature of zone 1 of the twin-screw extruder is 160-220°C; the temperature of zone 2 is 200-240°C; the temperature of zone 3 is 220-260°C; the temperature of zone 4 is 225-265°C; the head temperature is 200-260°C; and the screw speed is 255r / min.

[0016] Preferably, the mass ratio of HALS, polyethylene glycol and antioxidant is 2-5:0.1:1-1.7; the mass ratio of carbon quantum dot-polyacrylic acid core-shell structure and anti-yellowing agent is 1-4:1.

[0017] A light-resistant plastic for automobile interior parts is prepared by any one of the above preparation methods; the light-resistant plastic for automobile interior parts consists of polypropylene, acrylonitrile-butadiene-styrene, an anti-yellowing agent and a carbon quantum dot-polyacrylic acid core-shell structure.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention prepares functionalized lignin as an antioxidant, chemically grafts p-aminodiphenylamine to the surface of lignin through a bond of a silane molecule, and the Si-O-Si bond in the silane molecule is decomposed into silicon dioxide through high-temperature decomposition and heat absorption, which can cover the surface of the lignin as an insulating layer to block heat, prevent the decomposition of the carbon skeleton, and increase its decomposition temperature; and the lignin itself contains abundant active functional groups such as phenolic hydroxyl groups, has antioxidant ability, can capture free radicals generated by plastics under conditions such as light, thermal oxygen, etc., interrupt the free radical chain reaction, and thus inhibit the oxidative degradation process of the plastics; and after being modified by reaction with p-aminodiphenylamine and KH560, a functional group or structure with stronger antioxidant activity is further introduced, so that its free radical capture ability is significantly enhanced, and the aging reaction of the plastic caused by free radicals is more efficiently prevented, thereby extending the service life of the plastics.

[0020] 2. The present invention uses HALS, polyethylene glycol and antioxidant to prepare an anti-yellowing agent, and the anti-yellowing agent is obtained in powder form after spray drying. In light-resistant plastic materials, light aging and thermal-oxidative aging often occur simultaneously. The synergistic effect of light stabilizers and antioxidants can inhibit the aging process of plastics from different angles. This synergistic effect can significantly improve the antioxidant properties of plastic materials and reduce yellowing and mechanical property degradation caused by oxidation reactions. The powder form is convenient for addition during plastic processing. Whether it is injection molding, extrusion or other plastic molding processes, the powdered anti-yellowing agent will not cause problems such as mold clogging and melt fluidity, thereby improving the anti-aging performance of plastic products.

[0021] 3. The present invention prepares a carbon quantum dot-polyacrylic acid core-shell structure by electrospinning-post-treatment. The carbon quantum dots have certain antioxidant properties and good ultraviolet absorption characteristics. They can convert the absorbed light energy into low-energy light and emit it, reducing the accumulation of energy inside the material and the possibility of damage to the material molecular structure and yellowing caused by light energy. Polyacrylic acid, as a shell layer, can form a protective film on the surface of the material to prevent oxygen, moisture, etc. from directly contacting the material matrix and reduce the occurrence of oxidation reactions. At the same time, the core-shell structure formed by polyacrylic acid and carbon quantum dots can enhance the overall stability of the material, making the molecular structure of the material more difficult to be destroyed and improving its anti-aging performance.

[0022] 4. The present invention improves the anti-aging performance of the material by changing the mass ratio of HALS, polyethylene glycol and antioxidant in the anti-yellowing agent, as well as the mass ratio of carbon quantum dots-polyacrylic acid core-shell structure and anti-yellowing agent. Polyethylene glycol can be used as a carrier to help HALS better contact with antioxidants, so that they can play a more powerful synergistic role in inhibiting photooxidation reactions and delay the yellowing of automotive interior parts; in the process of scavenging free radicals, carbon quantum dots can be used as free radical capture sites, and work together with anti-yellowing agents to reduce the number of free radicals, thereby more effectively inhibiting the aging process of the material.

[0023] 5. The present invention improves the anti-aging performance of the material by reasonably controlling the temperature of the first zone, the second zone, the third zone, the fourth zone and the head temperature in the twin-screw extruder. The temperature of the first zone can plasticize the material and fully disperse the various components; the temperature of the second zone can fully melt the material that is not completely plasticized in the first zone, so that the various components can be better mixed; the temperature of the third zone can better embed the carbon quantum dot-polyacrylic acid core-shell structure into the resin matrix, and improve the light resistance of the material; the temperature of the fourth zone helps to ensure the distribution state of the additives inside the material; the head temperature can make the material form a good microstructure, which is conducive to improving the mechanical properties of the material such as strength and toughness, and also helps to maintain the uniform distribution of additives and improve the light aging resistance of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a graph showing the anti-aging performance test results of Example 12, Examples 15-18, and Comparative Examples 6-10 of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] See also Figure 1 The present invention provides a light aging resistant plastic for automobile interior decoration parts and a preparation method thereof. The technical scheme is as follows:

[0027] The substance information involved in the present invention is as follows:

[0028] Polypropylene CAS: 9003-07-0; acrylonitrile-butadiene-styrene copolymer CAS: 9003-56-9; polyethylene glycol CAS: 25322-68-3; p-aminodiphenylamine CAS: 101-54-2; KH560 CAS: 2530-83-8; lignin CAS: 8068-05-1; glucose CAS: 58367-01-4; polyacrylic acid CAS: 9003-01-4; toluene CAS: 108-88-3; sodium hydroxide CAS: 1310-73-2; N,N-dimethylformamide CAS: 68-12-2; N,N-methylenebisacrylamide CAS: 110-26-9; azobisisobutyronitrile CAS: 78-67-1; HALS was purchased from Beijing Tiangang Additive Co., Ltd.

[0029] Example 1

[0030] 9 g of p-aminodiphenylamine was dissolved in 450 ml of toluene, stirred at 80° C. for 1 h, 2.5 g of KH560 was added, and stirring was continued for 4.5 h to obtain a mixed solution; 30 g of lignin was dissolved in a sodium hydroxide aqueous solution, and the pH was adjusted to 10 to obtain an alkaline solution; the alkaline solution was added to the mixed solution, and the temperature was raised to 110° C. and stirred for 40 h to obtain an antioxidant;

[0031] HALS and polyethylene glycol were added into a high-speed disperser, and stirred at a speed of 1000 r / min for 10 minutes to obtain a dispersed system; an antioxidant was added into the dispersed system, the speed was reduced to 600 r / min, and stirring was continued for 5 minutes to obtain a mixed system; the mixed system was ultrasonically treated at a frequency of 20 kHz for 10 minutes and then spray-dried to obtain a powdered anti-yellowing agent; the inlet air temperature of the spray drying was controlled at 180°C and the outlet air temperature was 80°C; the mass ratio of HALS, polyethylene glycol and antioxidant was 2:0.1:1;

[0032] 4 g of glucose was dissolved in 25 ml of N, N-dimethylformamide, and after stirring and dissolving, 8 g of polyacrylic acid, 0.5 g of N, N-methylenebisacrylamide and 0.8 g of azobisisobutyronitrile were added, and stirring was continued for 30 min to obtain a spinning solution; the spinning solution was loaded into a syringe, and installed on an electrospinning device, the distance between the syringe needle and the receiving device was 12 cm, and electrospinning was performed under the conditions of a voltage of 10 kV and a spinning speed of 1 ml / h to obtain a composite fiber; the composite fiber was moved into a high-temperature furnace, and high-temperature annealing treatment was performed in a nitrogen atmosphere, and then vacuum dried to obtain a carbon quantum dot-polyacrylic acid core-shell structure; the high-temperature annealing treatment temperature was 850°C and the time was 2.5 h;

[0033] 70 parts of polypropylene and 40 parts of acrylonitrile-butadiene-styrene copolymer were added into a vacuum drying oven, dried at 80°C for 4 hours, then added into a high-speed mixer and stirred at a speed of 800 r / min for 20 minutes, carbon quantum dots-polyacrylic acid core-shell structure and 3.5 parts of anti-yellowing agent were added thereto, the speed was reduced to 500 r / min, stirring was continued for 10 minutes, 0.7 parts of zinc stearate were added and stirred for 5 minutes, and extrusion granulation was performed to obtain light aging resistant plastic for automotive interior parts; extrusion granulation was performed by a twin-screw extruder; the temperature of the first zone of the twin-screw extruder was 160°C; the temperature of the second zone was 200°C; the temperature of the third zone was 220°C; the temperature of the fourth zone was 225°C; the head temperature was 200°C; the screw speed was 255 r / min; the mass ratio of the carbon quantum dots-polyacrylic acid core-shell structure and the anti-yellowing agent was 1:1.

[0034] Example 2-12

[0035] Referring to the preparation method and parameter conditions of Example 1, the specific differences are shown in Table 1.

[0036] Table 1 Specific preparation parameters of Examples 2-12

[0037]

[0038] Comparative Example 1

[0039] The preparation method and parameter conditions are the same as those of Example 1, except that the lignin is dissolved in an aqueous sodium hydroxide solution and the pH is adjusted to 7.

[0040] Comparative Example 2

[0041] The preparation method and parameter conditions are the same as those of Example 1, except that no antioxidant is added to the dispersion system.

[0042] Comparative Example 3

[0043] The preparation method and parameter conditions are the same as those of Example 1, except that HALS, polyethylene glycol and antioxidant are added into a high-speed disperser at the same time for dispersion.

[0044] Example 8 Anti-aging performance test

[0045] The plastics of Examples 1-7 and Comparative Examples 1-3 were respectively put into a vulcanizer and pressed into sheets with a thickness of 1 mm, and then cold pressed and cut into sample strips of 2 cm×5 cm. According to the plastic laboratory light source exposure test method of GB / T16422.2-1999, they were placed in a xenon lamp exposure yellowing test box for irradiation, and then according to the plastic yellowness index test method of GB2409-80, their yellowness index was measured to obtain their yellowing index; the results are shown in Table 2.

[0046] Table 2 Anti-aging performance test of Examples 1-7 and Comparative Examples 1-3

[0047]

[0048]

[0049] As can be seen from Table 1 and Table 2, in Examples 1-3, by changing the pH of the alkaline solution, lignin and components such as p-aminodiphenylamine can be better combined to form a structure with stronger antioxidant capacity, providing good antioxidant protection. In Examples 2, 4-7, by changing the stirring speed and time of the dispersion system and the mixing system, sufficient shear force can be provided to make HALS and polyethylene glycol dispersed evenly, and a good synergistic effect can be exerted after adding the antioxidant. In Example 5, when preparing the antioxidant, the pH of the alkaline solution is adjusted to 11, and the antioxidant is used in the anti-aging agent. When the stirring speed of the dispersion system is 1300r / min and the stirring time is 12min, and the stirring speed of the mixing system is 700r / min and the stirring time is 10min, the anti-aging agent is used in the light-resistant aging plastic for automotive interior parts, which can optimize its anti-aging performance and the yellowing index is 0.40. In Comparative Example 1, lignin is dissolved in a sodium hydroxide aqueous solution and the pH is adjusted to 7. The solution is neutral, the degree of ionization of the lignin molecules is low, and the solubility is poor, resulting in that part of the lignin cannot be fully dissolved, and the phenolic hydroxyl reaction activity of the lignin is low, and the chemical reaction between it and the mixed solution of p-aminodiphenylamine and KH560 is difficult to fully occur, resulting in reduced yellowing resistance of the material; in Comparative Example 2, no antioxidant is added to the dispersion system, and the synergistic effect of the antioxidant is lacking. The plastic is easily oxidized and degraded due to thermal oxidation during processing and use, and ultimately reduces the yellowing resistance of the material; in Comparative Example 3, HALS, polyethylene glycol and antioxidant are added to a high-speed disperser at the same time for dispersion. Due to the different properties of each component, agglomerates are easily formed; and due to uneven dispersion and changes in the reaction order, the two effects of light stabilization and anti-oxidation cannot be fully coordinated, and when the material is exposed to light and oxidation, the occurrence of yellowing cannot be effectively suppressed.

[0050] Examples 9-13

[0051] Referring to the preparation method and parameter conditions of Example 5, the specific differences are shown in Table 3.

[0052] Comparative Example 4

[0053] The preparation method and parameter conditions are the same as those in Example 5, except that the mixed system is not subjected to ultrasonic treatment.

[0054] Comparative Example 5

[0055] The preparation method and parameter conditions are the same as those of Example 5, except that the anti-yellowing agent is not subjected to spray drying.

[0056] Example 14 Anti-aging performance test

[0057] The plastics of Example 5, Examples 9-13, and Comparative Examples 4-5 were respectively put into a vulcanizer to be pressed into sheets with a thickness of 1 mm, and then cold pressed and cut into sample strips of 2 cm×5 cm. According to the plastic laboratory light source exposure test method of GB / T16422.2-1999, they were placed in a xenon lamp exposure yellowing test box for irradiation, and then according to the plastic yellowness index test method of GB2409-80, their yellowness index was measured to obtain their yellowing index; the results are shown in Table 3.

[0058] Table 3 Anti-aging performance test of Example 5, Examples 9-13, Comparative Examples 4-5

[0059]

[0060] As can be seen from Table 3, in Examples 5, 9-13, the mixed system is subjected to ultrasonic treatment and the frequency and time are controlled, so that the HALS and antioxidant molecules can be better adsorbed on the polyethylene glycol molecular chain to form a more stable structure, and the ultrasonic cavitation effect can break the large particles in the mixed system into smaller particles. When applied to the material, the smaller particle size has better dispersibility and can be more easily evenly distributed in the material matrix, increasing the contact area with the material molecules, thereby more effectively inhibiting the yellowing phenomenon of the material under light and oxidation conditions; by spray drying, the mixed system is converted into a powdered anti-yellowing agent, which can be more evenly dispersed in the material and maintain its stable performance for a long time. By controlling the spray drying inlet and outlet air temperatures, the solvent in the mixed system can be quickly evaporated in a short time, while avoiding the decomposition or inactivation of the components due to high temperature. In Example 12, when the ultrasonic frequency is 30kHz and the time is 12min; the air inlet temperature of the spray drying treatment is 190°C and the air outlet temperature is 90°C, the obtained light aging resistant plastic for automotive interior parts has the best anti-aging performance, and the yellowing index is 0.32. In Comparative Example 4, no ultrasonic treatment was performed, and the HALS, polyethylene glycol and antioxidant in the mixed system could not be fully mixed at the microscopic level. The particle size in the mixed system was large and difficult to be evenly distributed in the matrix, so the yellowing index of the material increased; in Comparative Example 5, no spray drying treatment was performed, and the anti-yellowing agent remained in a liquid or semi-solid state, in which the solvent could not be effectively removed, which would cause the anti-yellowing agent component to slowly decompose, and it was difficult to evenly disperse during the mixing process with the plastic material.

[0061] Examples 15-18

[0062] Referring to the preparation method and parameter conditions of Example 12, the specific differences are shown in Table 4.

[0063] Comparative Example 6

[0064] The preparation method and parameter conditions are referred to in Example 12, except that a solvent-free induced phase separation-hydrothermal method is used to prepare the carbon quantum dot-polyacrylic acid core-shell structure.

[0065] Comparative Example 7

[0066] The preparation method and parameter conditions are similar to those of Example 12, except that a microemulsion method is used to prepare the carbon quantum dot-polyacrylic acid core-shell structure.

[0067] Comparative Example 8

[0068] The preparation method and parameter conditions are the same as those of Example 12, except that N,N-dimethylformamide is replaced by dimethyl sulfoxide.

[0069] Comparative Example 9

[0070] The preparation method and parameter conditions were similar to those of Example 12, except that the carbon source glucose was replaced by citric acid.

[0071] Comparative Example 10

[0072] The preparation method and parameter conditions are the same as those of Example 12, except that the carbon source glucose is replaced by sucrose.

[0073] Example 19 Anti-aging performance test

[0074] The plastics prepared in Example 12, Examples 15-18, and Comparative Examples 6-10 were respectively placed in a vulcanizer and pressed into sheets with a thickness of 1 mm, and then cold pressed and cut into 2 cm × 5 cm sample strips. According to the plastic laboratory light source exposure test method GB / T16422.2-1999, the plastics were placed in a xenon lamp exposure yellowing test box for irradiation; and then the tensile strength was tested according to the standard of GB / T1040.1-2018; the results are shown in Table 4 and Figure 1 As shown; in Table 4, stirring time 1 is the stirring time of the spinning solution; stirring time 2 is the stirring time after adding carbon quantum dots-polyacrylic acid core-shell structure and anti-yellowing agent in the preparation process of light aging resistant plastics for automotive interior parts; distance is the distance between the syringe needle and the receiving device; voltage is the voltage of the electrospinning equipment.

[0075] Table 4 Anti-aging performance test of Example 12, Examples 15-18, Comparative Examples 6-10

[0076]

[0077]

[0078] From Table 4 and Figure 1It can be seen that in Examples 12, 15-18, changing the stirring time 1, the distance between the syringe needle and the receiving device, the voltage of the electrospinning device, and the stirring time 2 can synergistically improve the anti-aging performance of the light-resistant plastic for automotive interior parts. In Example 15, when the stirring time of the spinning solution is 40 minutes, the distance between the syringe needle and the receiving device is 15 cm, the voltage of the electrospinning device is 14 kV, and the carbon quantum dot-polyacrylic acid core-shell structure and the anti-yellowing agent are added during the preparation of the light-resistant plastic for automotive interior parts and stirred for 20 minutes, the obtained material has the best anti-aging performance and is not easy to break. The tensile strength retention rate after the aging test is 89.6%. In Comparative Example 6, a solvent-free induced phase separation-hydrothermal method was used to prepare a carbon quantum dot-polyacrylic acid core-shell structure. During the solvent-free induced phase separation process, the phase transition and microstructure formation of the system were relatively complex, and it was difficult to accurately control the distribution of carbon quantum dots in polyacrylic acid and the morphology of the core-shell structure. Moreover, under the hydrothermal reaction conditions, the size and shape of the product also had large heterogeneity, resulting in poor integrity and uniformity of the core-shell structure, affecting the consistency of material performance. In Comparative Example 7, a microemulsion method was used to prepare a carbon quantum dot-polyacrylic acid core-shell structure. The droplet size of the microemulsion was usually small, which limited the growth of the carbon quantum dots. The size of the space and core-shell structure, and the microemulsion system is relatively complex. A large amount of impurities such as surfactants and oil phase will remain in the product. The separation and purification process is relatively cumbersome, which can easily lead to product loss or structural damage. In Comparative Example 8, dimethyl sulfoxide is used as a solvent, which has a high boiling point, resulting in a slower solvent evaporation rate, affecting the stretching and curing during the spinning process, making it difficult to control the diameter and morphology of the fiber. In addition, dimethyl sulfoxide may cause changes in the degree of stretching and aggregation state of the polyacrylic acid molecular chain, affecting its combination with carbon quantum dots, thereby adversely affecting the stability and performance of the final core-shell structure. In Comparative Example 9, when citric acid is used as the carbon source, the molecular structure of citric acid is more complex, and the properties of the generated carbon quantum dots such as particle size and crystallinity are difficult to accurately control due to the complexity and variability of the reaction process; in Comparative Example 10, when sucrose is used as the carbon source, sucrose is hygroscopic and easily absorbs moisture in the air during storage, causing its water content to change, thereby affecting the repeatability and stability of the reaction when it is used as a carbon source, and the damp sucrose will undergo partial hydrolysis, affecting the preparation effect of the carbon quantum dots.

[0079] Examples 20-23

[0080] Referring to the preparation method and parameter conditions of Example 15, the specific differences are shown in Table 5.

[0081] Comparative Example 11

[0082] The preparation method and parameter conditions were the same as those in Example 15, except that polyethylene glycol was not added.

[0083] Comparative Example 12

[0084] The preparation method and parameter conditions are the same as those of Example 15, except that HALS is replaced by bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate.

[0085] Comparative Example 13

[0086] The preparation method and parameter conditions are the same as those of Example 15, except that HALS is replaced by tris(1,2,2,6,6-pentamethyl-4-piperidinyl)phosphite.

[0087] Comparative Example 14

[0088] The preparation method and parameter conditions were similar to those of Example 15, except that the carbon quantum dot-polyacrylic acid core-shell structure was not added.

[0089] Example 24 Anti-aging performance test

[0090] The plastics of Example 15, Examples 20-23, and Comparative Examples 11-14 were respectively placed in a vulcanizer and pressed into sheets with a thickness of 1 mm, and then cold pressed and cut into 2 cm×5 cm sample strips. According to the plastic laboratory light source exposure test method GB / T16422.2-1999, they were placed in a xenon lamp exposure yellowing test box for irradiation, and then according to the plastic yellow index test method GB2409-80, the yellow index was measured to obtain the yellowing index; the results are shown in Table 5; the mass ratio of the three in Table 5 is the mass ratio of HALS, polyethylene glycol and antioxidant; the mass ratio of the two is the mass ratio of carbon quantum dot-polyacrylic acid core-shell structure and anti-yellowing agent.

[0091] Table 5 Anti-aging performance test of Example 15, Examples 20-23, Comparative Examples 11-14

[0092]

[0093] As can be seen from Table 5, in Examples 15, 20-23, HALS, polyethylene glycol and antioxidants are used to prepare anti-yellowing agents, and then the anti-yellowing agents and carbon quantum dots-polyacrylic acid core-shell structures are applied to light-resistant plastics for automotive interior parts. By controlling the proportion of each component, the components can be synergistically enhanced, thereby improving the anti-aging properties of the material. In Example 20, when the mass ratio of HALS, polyethylene glycol and antioxidant is 2.5:0.1:1.4, and the mass ratio of carbon quantum dots-polyacrylic acid core-shell structure and anti-yellowing agent is 2:1, the anti-aging properties of the light-resistant plastics for automotive interior parts prepared are the best, and the yellowing index is 0.25. In Comparative Example 11, polyethylene glycol was not added, and there was a strong intermolecular force between HALS molecules, making it difficult to form a uniform dispersion system; and polyethylene glycol can be used as a carrier to promote the interaction between HALS and antioxidants. Without polyethylene glycol, the mixing of HALS and antioxidants is not uniform enough, affecting the synergistic effect between the two, and it is impossible to effectively inhibit the yellowing phenomenon of the material caused by the simultaneous action of light and oxidation. In Comparative Example 12, HALS is replaced with bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate as a light stabilizer. During long-term use, migration and volatilization are prone to occur, resulting in a decrease in the concentration of the light stabilizer inside the material, and the photooxidation reaction cannot be effectively inhibited, causing the light stabilization effect of the material to gradually deteriorate. In Comparative Example 13, HALS is replaced with tris(1,2,2,6,6-pentamethyl-4-piperidinyl) phosphite as a light stabilizer, which has poor compatibility and cannot play its light stabilization role well. In Comparative Example 14, the carbon quantum dot-polyacrylic acid core-shell structure is not added, and ultraviolet rays can act more directly on polypropylene and acrylonitrile-butadiene-styrene copolymer, and the molecular chains are easily broken, resulting in powdering and brittleness of the material surface, decreased mechanical properties, and yellowing of the color due to photo-oxidation.

[0094] Examples 25-30

[0095] Referring to the preparation method and parameter conditions of Example 20, the specific differences are shown in Table 6.

[0096] Table 6 Specific preparation parameters of Examples 25-30

[0097] Example Zone 1 temperature / ℃ Temperature of zone 2 / ℃ Three-zone temperature / ℃ Four zone temperature / ℃ Head temperature / ℃ Embodiment 25 170 220 230 235 220 Embodiment 26 180 230 240 245 240 Embodiment 27 220 240 260 265 260 Embodiment 28 200 220 235 245 235 Embodiment 29 160 240 260 260 200 Embodiment 30 220 200 230 225 260

[0098] Example 31 Anti-aging performance test

[0099] The plastics of Example 20 and Examples 25-30 were respectively placed in a vulcanizer and pressed into sheets with a thickness of 1 mm, and then cold pressed and cut into 2 cm×5 cm sample strips. According to the plastic laboratory light source exposure test method of GB / T16422.2-1999, they were placed in a xenon lamp exposure yellowing test box for irradiation; and then the tensile strength was tested according to the standard of GB / T1040.1-2018; the results are shown in Table 7.

[0100] Table 7 Anti-aging performance test of Example 20, Examples 25-30

[0101]

[0102]

[0103] As can be seen from Table 1 and Table 7, in Examples 20, 25-30, if the temperature of the first zone of the twin-screw extruder is too low, it is not conducive to the dispersion of the additive in the resin, and agglomeration may occur. If the temperature is too high, the material will begin to degrade at the screw inlet, especially for acrylonitrile-butadiene-styrene copolymer containing double bonds, the double bonds are more likely to react at high temperatures, causing the material to become brittle and the color to change; the temperature of the second zone affects the further plasticization of the material; the temperature of the third zone has an important influence on the uniform mixing of the material, and can promote the reaction and enhance the material performance; the temperature of the fourth zone has a great influence on the fluidity of the material and the appearance quality of the final product. In Example 28, when the temperature of the first zone is 200 degrees Celsius, the temperature of the second zone is 220 degrees Celsius, the temperature of the third zone is 235 degrees Celsius, the temperature of the fourth zone is 245 degrees Celsius, and the head temperature is 235 degrees Celsius, the tensile strength retention rate of the light aging-resistant plastic for automotive interior parts obtained is 93.8%, and its anti-aging performance is the best.

[0104] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing light-resistant plastics for automotive interior parts, characterized in that: The preparation method is as follows: polypropylene and acrylonitrile-butadiene-styrene copolymer are added into a vacuum drying oven, dried at 80° C. for 4 hours, added into a high-speed mixer, stirred at a speed of 800 r / min for 20 minutes, carbon quantum dots-polyacrylic acid core-shell structure and anti-yellowing agent are added thereto, the speed is reduced to 500 r / min, stirring is continued for 10-30 minutes, zinc stearate is added and stirred for 5 minutes, and extrusion granulation is performed to obtain the light aging resistant plastic for automotive interior parts; The anti-yellowing agent is obtained by mixing HALS, polyethylene glycol and an antioxidant, ultrasonically and spray-drying; The antioxidant is obtained by reacting p-aminodiphenylamine, KH560 and lignin; The carbon quantum dot-polyacrylic acid core-shell structure is prepared from glucose and polyacrylic acid by an electrostatic spinning-post-treatment method.

2. The method for preparing a light-resistant plastic for automobile interior decoration parts according to claim 1, characterized in that: The preparation method of the anti-yellowing agent is as follows: adding the HALS and the polyethylene glycol into a high-speed disperser, stirring at a speed of 1000-1500 r / min for 10-20 minutes to obtain a dispersed system; adding the antioxidant into the dispersed system, reducing the speed to 600-800 r / min, and continuing stirring for 5-15 minutes to obtain a mixed system; subjecting the mixed system to ultrasonic treatment at a frequency of 20-40 kHz for 10-15 minutes and then spray drying to obtain the anti-yellowing agent; the anti-yellowing agent is in powder form.

3. The method for preparing a light-resistant plastic for automobile interior decoration parts according to claim 2, characterized in that: The inlet air temperature of the spray drying is controlled at 180-200°C, and the outlet air temperature is 80-100°C.

4. The method for preparing a light-resistant plastic for automobile interior parts according to claim 1, characterized in that: The preparation method of the antioxidant is as follows: dissolving the p-aminodiphenylamine in toluene, stirring at 80° C. for 1 hour, adding the KH560, and continuing to stir for 4.5 hours to obtain a mixed solution; dissolving the lignin in a sodium hydroxide aqueous solution, adjusting the pH to 10-12, and obtaining an alkaline solution; adding the alkaline solution to the mixed solution, heating to 110° C. and stirring for 40 hours to obtain the antioxidant.

5. The method for preparing a light-resistant plastic for automobile interior parts according to claim 1, characterized in that: The preparation method of the carbon quantum dot-polyacrylic acid core-shell structure is as follows: dissolving the glucose in N,N-dimethylformamide, adding the polyacrylic acid, N,N-methylenebisacrylamide and azobisisobutyronitrile after stirring and dissolving, and continuing to stir for 30-50 minutes to obtain a spinning solution; loading the spinning solution into a syringe, installing it on an electrospinning device, the distance between the syringe needle and the receiving device is 12-18 cm, and electrospinning is performed under the conditions of a voltage of 10-18 kV and a spinning speed of 1 ml / h to obtain a composite fiber; moving the composite fiber into a high-temperature furnace, performing a high-temperature annealing treatment in a nitrogen atmosphere, and then vacuum drying to obtain the carbon quantum dot-polyacrylic acid core-shell structure; the high-temperature annealing treatment temperature is 850° C. and the time is 2.5 hours.

6. The method for preparing a light-resistant plastic for automobile interior decoration parts according to claim 1, characterized in that: The extrusion granulation is carried out by a twin-screw extruder; the temperature of the first zone of the twin-screw extruder is 160-220°C; the temperature of the second zone is 200-240°C; the temperature of the third zone is 220-260°C; the temperature of the fourth zone is 225-265°C; the head temperature is 200-260°C; and the screw speed is 255r / min.

7. The method for preparing a light-resistant plastic for automobile interior decoration parts according to claim 1, characterized in that: The mass ratio of the HALS, the polyethylene glycol and the antioxidant is 2-5: 0.1:1-1.7; the mass ratio of the carbon quantum dot-polyacrylic acid core-shell structure to the anti-yellowing agent is 1-4:

1.

8. A light-resistant plastic for automotive interior parts, characterized in that: The light aging resistant plastic for automobile interior parts is prepared by the preparation method described in any one of claims 1 to 7; the light aging resistant plastic for automobile interior parts consists of polypropylene, acrylonitrile-butadiene-styrene, an anti-yellowing agent and a carbon quantum dot-polyacrylic acid core-shell structure.

Images