Aging-resistant plastic and its use

Abstract

The application relates to the technical field of plastics, in particular to an anti-aging plastic and application thereof. The anti-aging plastic is composed of polypropylene, low-density polyethylene, loaded DLTP organic montmorillonite, intercalated montmorillonite, a compatilizer and a lubricant. The intercalated montmorillonite prepared by using a solvent intercalation method is added into raw materials, the montmorillonite is modified by a functionalized quaternary ammonium salt, and the loaded DLTP organic montmorillonite prepared by further loading an antioxidant DLTP is used, so that the anti-aging property, the mechanical property and the environmental stability of the material are remarkably improved, the material preparation process is simple, the material is suitable for continuous production of a double-screw extruder, and the material is widely applied in the fields of automobiles, electronic appliances, buildings and outdoor packaging and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of plastics technology, and more specifically to an aging-resistant plastic and its applications. Background Technology

[0002] Plastics have advantages such as light weight, stable chemical properties, no corrosion, good impact resistance, good transparency, good insulation, good colorability, and low processing cost. Polypropylene is a high-performance thermoplastic synthetic resin. It is a colorless, semi-transparent, lightweight, general-purpose thermoplastic plastic with chemical resistance, heat resistance, electrical insulation, high mechanical strength, and good wear resistance. It has been widely developed and applied in many fields such as machinery, automobiles, electronics, construction, textiles, packaging, agriculture, forestry, fisheries, and food industry.

[0003] Patent document CN111484673B discloses a modified polypropylene plastic. This invention improves the mechanical properties and toughness of polypropylene plastic by adding silicone powder. By compounding silicone powder and PE wax, the mechanical properties of polypropylene plastic are further improved. Patent document CN116253951B discloses a flame-retardant polypropylene plastic. This invention improves the performance of polypropylene plastic by using a composite flame retardant. The composite flame retardant is non-toxic, harmless, highly efficient and safe, giving polypropylene plastic uniform, long-lasting, non-toxic, harmless, highly efficient and safe flame-retardant properties.

[0004] However, when plastics are used outdoors or in other environments, their lifespan is often affected by aging. Summary of the Invention

[0005] In view of this, the purpose of this invention is to propose an aging-resistant plastic and its application, so as to solve the problems of poor aging resistance and short service life of traditional plastics.

[0006] To achieve the above objectives, the present invention provides an aging-resistant plastic, which is prepared from the following raw materials in parts by weight: 100-110 parts polypropylene, 10-15 parts low-density polyethylene, 10-15 parts DLTP-loaded organomontmorillonite, 5-7 parts intercalated montmorillonite, 3-7 parts crosslinking agent, 1-2 parts sulfur, 1-2 parts compatibilizer and 1-2 parts lubricant.

[0007] The intercalated montmorillonite is prepared by solvent intercalation of antioxidant 1010 and nano-montmorillonite in acetone;

[0008] The preparation steps of the DLTP-loaded organomontmorillonite are as follows:

[0009] S1: Under a nitrogen atmosphere, 1-vinyl-1,2,4-triazole and p-methoxyphenol were added to anhydrous acetonitrile, cooled to 2-4°C in an ice bath, and then 1,5-dibromopentane was added. The mixture was stirred at room temperature for 12 hours, and then 1,3,5-tris(bromomethyl)benzene and 1-bromododecane were added. The mixture was heated to 60°C and stirred for 10-12 hours. The mixture was then purified by rotary evaporation and vacuum dried to obtain the functionalized quaternary ammonium salt.

[0010] S2: Add nano-montmorillonite to deionized water and sonicate at 60℃ to obtain a suspension; separately dissolve octadecyltrimethylammonium chloride and functionalized quaternary ammonium salt in ethanol (60℃), stir evenly and add to the suspension, maintain the temperature at 60℃, continue stirring for 5-6 hours, after the reaction is completed, centrifuge to collect the precipitate, purify, and obtain quaternary ammonium salt intercalated organomontmorillonite.

[0011] S3: Mel-intercalation of dilauryl thiopropionate (DLTP) with quaternary ammonium salt-intercalated organomontmorillonite yields DLTP-loaded organomontmorillonite.

[0012] Preferably, the polypropylene is Zhejiang Petrochemical K8003.

[0013] Preferably, the low-density polyethylene is Zhenhai Refining & Chemical 7050H.

[0014] Preferably, the crosslinking agent is dicumyl peroxide.

[0015] Preferably, the compatibilizer is polypropylene grafted with maleic anhydride.

[0016] Preferably, the lubricant is one of polyethylene wax and calcium stearate.

[0017] Preferably, the ratio of antioxidant 1010, acetone, and nano-montmorillonite is 3.6-4.5g:50-80mL:3-3.6g.

[0018] Preferably, the length of the nano-montmorillonite is 400-500 nm and the interlayer spacing is 1.2-1.4 nm.

[0019] Preferably, the ratio of 1-vinyl-1,2,4-triazole, p-methoxyphenol, anhydrous acetonitrile, 1,5-dibromopentane, 1,3,5-tris(bromomethyl)benzene, and 1-bromododecane in step S1 is 1.5-2.5g:0.01-0.02g:90-100g:1-2g:0.4-0.5g:0.4-0.5g.

[0020] Preferably, the ratio of nano-montmorillonite, deionized water, octadecyltrimethylammonium chloride, functionalized quaternary ammonium salt, and ethanol in step S2 is 10-15g:500mL:2-3g:1.5-3g:100-200mL.

[0021] Preferably, the nano-montmorillonite in step S2 has a particle size of 171214154750, purchased from Kramar.

[0022] Preferably, the purification in step S2 involves washing three times with ethanol / water (1:1) and finally drying under vacuum at 60°C for 24 hours.

[0023] Preferably, the ratio of dilauryl thiopropionate (DLTP) to quaternary ammonium salt-intercalated organomontmorillonite in step S3 is 5-10g:10-15g.

[0024] Preferably, the temperature of the molten intercalation in step S3 is 120°C and the time is 15-20 min.

[0025] Preferably, the preparation steps of the aging-resistant plastic are as follows: polypropylene, low-density polyethylene, DLTP-loaded organomontmorillonite, intercalated montmorillonite, crosslinking agent, compatibilizer and lubricant are placed in a high-speed mixer and mixed evenly, and then fed into a twin-screw extruder for extrusion granulation to obtain the aging-resistant plastic material.

[0026] Preferably, the screw length-to-diameter ratio of the twin-screw extruder is 45, and the feeding and discharging temperatures are: 130°C for the first stage, 170°C for the second stage, 190°C for the third stage, 170°C for the fourth stage, and 160°C for the fifth stage.

[0027] Furthermore, the present invention also provides an application of aging-resistant plastics in the fields of automobiles, electronics, construction and outdoor packaging.

[0028] The beneficial effects of this invention are:

[0029] This invention innovatively employs a dual composite system of intercalated montmorillonite and DLTP-loaded organomontmorillonite to construct a multi-layered synergistic anti-aging protection network. Through the difference in interlayer spacing between the two types of montmorillonite (the intercalated montmorillonite has a smaller interlayer spacing while the organomontmorillonite has a larger interlayer spacing), the antioxidant can exhibit a dual release mode of "rapid response - continuous protection". This synergistic effect in the time dimension significantly improves the long-term weather resistance of the material.

[0030] This invention achieves multiple interfacial enhancement effects by introducing rigid benzene ring structures and long-chain alkyl structures simultaneously on the surface of montmorillonite through the special molecular design of functionalized quaternary ammonium salts. This dual modification not only expands the interlayer spacing of montmorillonite, which is beneficial to the loading and release of antioxidants, but more importantly, it forms a strong interfacial bond in the polymer matrix, which effectively promotes stress transfer and energy dissipation, enabling the material to have both high hardness and good impact toughness.

[0031] This invention achieves nanoscale uniform dispersion of montmorillonite in a polymer matrix through a stepwise intercalation and functionalization modification process design. The intercalation treatment with antioxidant 1010 imparts suitable polarity to the montmorillonite sheet surface, while the organic treatment with functionalized quaternary ammonium salts modulates the compatibility between montmorillonite and the matrix, ensuring the formation of a stable nanoscale dispersion system. Its sheet structure constructs tortuous barrier pathways within the matrix, effectively slowing the penetration rate of oxygen, moisture, and ultraviolet radiation. Simultaneously, the uniformly dispersed montmorillonite sheets act as a physical reinforcing phase, significantly improving the surface hardness and dimensional stability of the material. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0033] The properties or sources of the raw materials used in the embodiments and comparative examples of this invention are as follows:

[0034] Polypropylene: Zhejiang Petrochemical K8003; Low-density polyethylene: Zhenhai Refining & Chemical 7050H; Nano-montmorillonite: Length: 400-500nm, interlayer spacing: 1.2-1.4nm.

[0035] Example 1: An aging-resistant plastic, the specific preparation steps are as follows:

[0036] (1) 3g of nano-montmorillonite was pretreated at 80℃ for 30min to obtain pretreated nano-montmorillonite; then 3.6g of antioxidant 1010 was dissolved in 50mL of acetone, the pretreated nano-montmorillonite was added, ultrasonically treated for 30min, stirred continuously at 50℃ for 2h, and rotary evaporated to obtain intercalated montmorillonite.

[0037] (2) Under a nitrogen atmosphere, 1.5 g of 1-vinyl-1,2,4-triazole and 0.01 g of p-methoxyphenol were added to 90 g of anhydrous acetonitrile, cooled to 2 °C in an ice bath, and then 1 g of 1,5-dibromopentane was added. The mixture was stirred at room temperature for 12 h, and then 0.4 g of 1,3,5-tris(bromomethyl)benzene and 0.4 g of 1-bromododecane were added. The mixture was heated to 60 °C and stirred for 10 h. The mixture was then rotary evaporated and reprecipitated twice with methanol / dichloromethane (volume ratio 1:1). The mixture was then dried under vacuum to obtain the functionalized quaternary ammonium salt.

[0038] (3) Add 10g of nano-montmorillonite to 500mL of deionized water and sonicate at 60℃ to obtain a suspension; take 2g of octadecyltrimethylammonium chloride and 1.5g of functionalized quaternary ammonium salt and dissolve them in 100mL of hot ethanol (60℃), stir evenly and add them to the suspension, keep the temperature at 60℃ and continue stirring for 5h. After the reaction is completed, centrifuge to collect the precipitate, wash it 3 times with ethanol / water (1:1), and finally vacuum dry at 60℃ for 24h to obtain quaternary ammonium salt intercalated organomontmorillonite;

[0039] (4) 5g of dilauryl thiopropionate (DLTP) and 10g of quaternary ammonium salt-intercalated organomontmorillonite were melt-intercalated at 120°C for 15min to obtain DLTP-loaded organomontmorillonite.

[0040] (5) 100g polypropylene, 10g low-density polyethylene, 10g loaded DLTP organomontmorillonite, 5g intercalated montmorillonite, 3g dicumyl peroxide, 1g sulfur, 1g polypropylene grafted maleic anhydride and 1g polyethylene wax are placed in a high-speed mixer and mixed evenly. Then, the mixture is fed into a twin-screw extruder for extrusion granulation to obtain an aging-resistant plastic material. The twin-screw extruder is a co-rotating twin-screw extruder with a screw length-to-diameter ratio of 45. The feed temperature to discharge temperature is as follows: 130℃ for the first stage, 170℃ for the second stage, 190℃ for the third stage, 170℃ for the fourth stage and 160℃ for the fifth stage.

[0041] Example 2: An aging-resistant plastic, the specific preparation steps are as follows:

[0042] (1) 3.3g of nano-montmorillonite was pretreated at 80℃ for 30min to obtain pretreated nano-montmorillonite; then 4g of antioxidant 1010 was dissolved in 70mL of acetone, the pretreated nano-montmorillonite was added, ultrasonically treated for 30min, stirred continuously at 50℃ for 3h, and rotary evaporated to obtain intercalated montmorillonite.

[0043] (2) Under a nitrogen atmosphere, 2g of 1-vinyl-1,2,4-triazole and 0.015g of p-methoxyphenol were added to 95g of anhydrous acetonitrile, cooled to 3°C in an ice bath, and then 1.5g of 1,5-dibromopentane were added. The mixture was stirred at room temperature for 12h, and then 0.45g of 1,3,5-tris(bromomethyl)benzene and 0.45g of 1-bromododecane were added. The mixture was heated to 60°C and stirred for 11h. The mixture was then rotary evaporated and reprecipitated twice with methanol / dichloromethane (volume ratio 1:1). The mixture was then dried under vacuum to obtain the functionalized quaternary ammonium salt.

[0044] (3) Add 13g of nano-montmorillonite to 500mL of deionized water and sonicate at 60℃ to obtain a suspension; separately take 2.5g of octadecyltrimethylammonium chloride and 2.5g of functionalized quaternary ammonium salt and dissolve them in 150mL of hot ethanol (60℃), stir evenly and add them to the suspension, keep the temperature at 60℃ and continue stirring for 6h. After the reaction is completed, centrifuge to collect the precipitate, wash it 3 times with ethanol / water (1:1), and finally vacuum dry at 60℃ for 24h to obtain quaternary ammonium salt intercalated organomontmorillonite;

[0045] (4) 8g of dilauryl thiopropionate (DLTP) and 13g of quaternary ammonium salt-intercalated organomontmorillonite were melt-intercalated at 120°C for 18min to obtain DLTP-loaded organomontmorillonite.

[0046] (5) 105g polypropylene, 13g low-density polyethylene, 13g loaded DLTP organic montmorillonite, 6g intercalated montmorillonite, 5g dicumyl peroxide, 1.5g sulfur, 1.5g polypropylene grafted maleic anhydride and 1.5g polyethylene wax are mixed evenly in a high-speed mixer and then fed into a twin-screw extruder for extrusion granulation to obtain an aging-resistant plastic material. The twin-screw extruder is a co-rotating twin-screw extruder with a screw length-to-diameter ratio of 45. The feed temperature to discharge temperature is: 130℃ for the first section, 170℃ for the second section, 190℃ for the third section, 170℃ for the fourth section and 160℃ for the fifth section.

[0047] Example 3: An aging-resistant plastic, the specific preparation steps are as follows:

[0048] (1) 3.6g of nano-montmorillonite was pretreated at 80℃ for 30min to obtain pretreated nano-montmorillonite; then 4.5g of antioxidant 1010 was dissolved in 80mL of acetone, the pretreated nano-montmorillonite was added, ultrasonically treated for 30min, and then stirred continuously at 50℃ for 3h, and rotary evaporated to obtain intercalated montmorillonite.

[0049] (2) Under a nitrogen atmosphere, 2.5 g of 1-vinyl-1,2,4-triazole and 0.02 g of p-methoxyphenol were added to 100 g of anhydrous acetonitrile, cooled to 4 °C in an ice bath, and then 2 g of 1,5-dibromopentane were added. The mixture was stirred at room temperature for 12 h, and then 0.5 g of 1,3,5-tris(bromomethyl)benzene and 0.5 g of 1-bromododecane were added. The mixture was heated to 60 °C and stirred for 12 h. The mixture was then rotary evaporated and reprecipitated twice with methanol / dichloromethane (volume ratio 1:1). The mixture was then dried under vacuum to obtain the functionalized quaternary ammonium salt.

[0050] (3) Add 15g of nano-montmorillonite to 500mL of deionized water and sonicate at 60℃ to obtain a suspension; separately take 3g of octadecyltrimethylammonium chloride and 3g of functionalized quaternary ammonium salt and dissolve them in 200mL of hot ethanol (60℃), stir evenly and add them to the suspension, keep the temperature at 60℃ and continue stirring for 6h. After the reaction is completed, centrifuge to collect the precipitate, wash it 3 times with ethanol / water (1:1), and finally vacuum dry at 60℃ for 24h to obtain quaternary ammonium salt intercalated organomontmorillonite;

[0051] (4) 10g of dilauryl thiopropionate (DLTP) and 15g of quaternary ammonium salt-intercalated organomontmorillonite were melt-intercalated at 120°C for 20min to obtain DLTP-loaded organomontmorillonite.

[0052] (5) 110g polypropylene, 15g low-density polyethylene, 15g loaded DLTP organic montmorillonite, 7g intercalated montmorillonite, 7g dicumyl peroxide, 2g sulfur, 2g polypropylene grafted maleic anhydride and 2g polyethylene wax are placed in a high-speed mixer and mixed evenly. Then the mixture is fed into a twin-screw extruder for extrusion granulation to obtain an aging-resistant plastic material. The twin-screw extruder is a co-rotating twin-screw extruder with a screw length-to-diameter ratio of 45. The feed temperature to discharge temperature is: 130℃ for the first stage, 170℃ for the second stage, 190℃ for the third stage, 170℃ for the fourth stage and 160℃ for the fifth stage.

[0053] Comparative Example 1: The difference from Example 2 is that intercalated montmorillonite is not added. The specific steps are as follows:

[0054] (1) Under a nitrogen atmosphere, 2g of 1-vinyl-1,2,4-triazole and 0.015g of p-methoxyphenol were added to 95g of anhydrous acetonitrile, cooled to 3°C in an ice bath, and then 1.5g of 1,5-dibromopentane were added. The mixture was stirred at room temperature for 12h, and then 0.45g of 1,3,5-tris(bromomethyl)benzene and 0.45g of 1-bromododecane were added. The mixture was heated to 60°C and stirred for 11h. The mixture was then rotary evaporated and reprecipitated twice with methanol / dichloromethane (volume ratio 1:1). The mixture was then dried under vacuum to obtain the functionalized quaternary ammonium salt.

[0055] (2) 13g of nano-montmorillonite was added to 500mL of deionized water and ultrasonically treated at 60℃ to obtain a suspension; 2.5g of octadecyltrimethylammonium chloride and 2.5g of functionalized quaternary ammonium salt were dissolved in 150mL of hot ethanol (60℃), stirred evenly and added to the suspension. The temperature was kept at 60℃ and stirred for 6h. After the reaction was completed, the precipitate was collected by centrifugation, washed 3 times with ethanol / water (1:1), and finally vacuum dried at 60℃ for 24h to obtain quaternary ammonium salt intercalated organo-montmorillonite.

[0056] (3) 8g of dilauryl thiopropionate (DLTP) and 13g of quaternary ammonium salt-intercalated organomontmorillonite were melt-intercalated at 120°C for 18min to obtain DLTP-loaded organomontmorillonite.

[0057] (4) 105g polypropylene, 13g low-density polyethylene, 19g loaded DLTP organomontmorillonite, 5g dicumyl peroxide, 1.5g sulfur, 1.5g polypropylene grafted maleic anhydride and 1.5g polyethylene wax are placed in a high-speed mixer and mixed evenly. Then, the mixture is fed into a twin-screw extruder for extrusion granulation to obtain an aging-resistant plastic material. The twin-screw extruder is a co-rotating twin-screw extruder with a screw length-to-diameter ratio of 45. The feed temperature is as follows: 130℃ for the first stage, 170℃ for the second stage, 190℃ for the third stage, 170℃ for the fourth stage and 160℃ for the fifth stage.

[0058] Comparative Example 2: The difference from Example 2 is that no DLTP-loaded organomontmorillonite was added. The specific steps are as follows:

[0059] (1) 3.3g of nano-montmorillonite was pretreated at 80℃ for 30min to obtain pretreated nano-montmorillonite; then 4g of antioxidant 1010 was dissolved in 70mL of acetone, the pretreated nano-montmorillonite was added, ultrasonically treated for 30min, stirred continuously at 50℃ for 3h, and rotary evaporated to obtain intercalated montmorillonite.

[0060] (2) 105g polypropylene, 13g low-density polyethylene, 19g intercalated montmorillonite, 5g dicumyl peroxide, 1.5g sulfur, 1.5g polypropylene grafted maleic anhydride and 1.5g polyethylene wax are placed in a high-speed mixer and mixed evenly. Then, the mixture is fed into a twin-screw extruder for extrusion granulation to obtain an aging-resistant plastic material. The twin-screw extruder is a co-rotating twin-screw extruder with a screw length-to-diameter ratio of 45. The feed temperature is as follows: 130℃ for the first stage, 170℃ for the second stage, 190℃ for the third stage, 170℃ for the fourth stage and 160℃ for the fifth stage.

[0061] Comparative Example 3: The difference from Example 2 is that no functionalized quaternary ammonium salt is added in step (3). The specific steps are as follows:

[0062] (1) 3.3g of nano-montmorillonite was pretreated at 80℃ for 30min to obtain pretreated nano-montmorillonite; then 4g of antioxidant 1010 was dissolved in 70mL of acetone, the pretreated nano-montmorillonite was added, ultrasonically treated for 30min, stirred continuously at 50℃ for 3h, and rotary evaporated to obtain intercalated montmorillonite.

[0063] (2) 13g of nano-montmorillonite was added to 500mL of deionized water and ultrasonically treated at 60℃ to obtain a suspension; 2.5g of octadecyltrimethylammonium chloride was dissolved in 150mL of hot ethanol (60℃), stirred evenly and added to the suspension. The temperature was kept at 60℃ and stirred for 6h. After the reaction was completed, the precipitate was collected by centrifugation, washed 3 times with ethanol / water (1:1), and finally vacuum dried at 60℃ for 24h to obtain quaternary ammonium salt intercalated organomontmorillonite.

[0064] (3) 8g of dilauryl thiopropionate (DLTP) and 13g of quaternary ammonium salt-intercalated organomontmorillonite were melt-intercalated at 120°C for 18min to obtain DLTP-loaded organomontmorillonite.

[0065] (4) 105g polypropylene, 13g low-density polyethylene, 13g loaded DLTP organomontmorillonite, 6g intercalated montmorillonite, 5g dicumyl peroxide, 1.5g sulfur, 1.5g polypropylene grafted maleic anhydride, and 1.5g polyethylene wax are mixed evenly in a high-speed mixer and then fed into a twin-screw extruder for extrusion granulation to obtain an aging-resistant plastic material. The twin-screw extruder is a co-rotating twin-screw extruder with a screw length-to-diameter ratio of 45. The feed temperature to discharge temperature is: 130℃ for the first stage, 170℃ for the second stage, 190℃ for the third stage, 170℃ for the fourth stage, and 160℃ for the fifth stage.

[0066] Comparative Example 4: The difference from Example 2 is that 1,3,5-tris(bromomethyl)benzene is not added in step (2). The specific steps are as follows:

[0067] (1) 3.3g of nano-montmorillonite was pretreated at 80℃ for 30min to obtain pretreated nano-montmorillonite; then 4g of antioxidant 1010 was dissolved in 70mL of acetone, the pretreated nano-montmorillonite was added, ultrasonically treated for 30min, stirred continuously at 50℃ for 3h, and rotary evaporated to obtain intercalated montmorillonite.

[0068] (2) Under a nitrogen atmosphere, 2g of 1-vinyl-1,2,4-triazole and 0.015g of p-methoxyphenol were added to 95g of anhydrous acetonitrile, cooled to 3°C in an ice bath, and then 1.5g of 1,5-dibromopentane was added. The mixture was stirred at room temperature for 12h, and then 0.45g of 1-bromododecane was added. The mixture was heated to 60°C and stirred for 11h. The mixture was then rotary evaporated and reprecipitated twice with methanol / dichloromethane (volume ratio 1:1). The mixture was then dried under vacuum to obtain the functionalized quaternary ammonium salt.

[0069] (3) Add 13g of nano-montmorillonite to 500mL of deionized water and sonicate at 60℃ to obtain a suspension; separately take 2.5g of octadecyltrimethylammonium chloride and 2.5g of functionalized quaternary ammonium salt and dissolve them in 150mL of hot ethanol (60℃), stir evenly and add them to the suspension, keep the temperature at 60℃ and continue stirring for 6h. After the reaction is completed, centrifuge to collect the precipitate, wash it 3 times with ethanol / water (1:1), and finally vacuum dry at 60℃ for 24h to obtain quaternary ammonium salt intercalated organomontmorillonite;

[0070] (4) 8g of dilauryl thiopropionate (DLTP) and 13g of quaternary ammonium salt-intercalated organomontmorillonite were melt-intercalated at 120°C for 18min to obtain DLTP-loaded organomontmorillonite.

[0071] (5) 105g polypropylene, 13g low-density polyethylene, 13g loaded DLTP organic montmorillonite, 6g intercalated montmorillonite, 5g dicumyl peroxide, 1.5g sulfur, 1.5g polypropylene grafted maleic anhydride and 1.5g polyethylene wax are mixed evenly in a high-speed mixer and then fed into a twin-screw extruder for extrusion granulation to obtain an aging-resistant plastic material. The twin-screw extruder is a co-rotating twin-screw extruder with a screw length-to-diameter ratio of 45. The feed temperature to discharge temperature is: 130℃ for the first section, 170℃ for the second section, 190℃ for the third section, 170℃ for the fourth section and 160℃ for the fifth section.

[0072] Comparative Example 5: The difference from Example 2 is that 1-bromododecane is not added in step (2). The specific steps are as follows:

[0073] (1) 3.3g of nano-montmorillonite was pretreated at 80℃ for 30min to obtain pretreated nano-montmorillonite; then 4g of antioxidant 1010 was dissolved in 70mL of acetone, the pretreated nano-montmorillonite was added, ultrasonically treated for 30min, stirred continuously at 50℃ for 3h, and rotary evaporated to obtain intercalated montmorillonite.

[0074] (2) Under a nitrogen atmosphere, 2g of 1-vinyl-1,2,4-triazole and 0.015g of p-methoxyphenol were added to 95g of anhydrous acetonitrile, cooled to 3°C in an ice bath, and then 1.5g of 1,5-dibromopentane was added. The mixture was stirred at room temperature for 12h, and then 0.45g of 1,3,5-tris(bromomethyl)benzene was added. The mixture was heated to 60°C and stirred for 11h. The mixture was then rotary evaporated and reprecipitated twice with methanol / dichloromethane (volume ratio 1:1). The mixture was then dried under vacuum to obtain the functionalized quaternary ammonium salt.

[0075] (3) Add 13g of nano-montmorillonite to 500mL of deionized water and sonicate at 60℃ to obtain a suspension; separately take 2.5g of octadecyltrimethylammonium chloride and 2.5g of functionalized quaternary ammonium salt and dissolve them in 150mL of hot ethanol (60℃), stir evenly and add them to the suspension, keep the temperature at 60℃ and continue stirring for 6h. After the reaction is completed, centrifuge to collect the precipitate, wash it 3 times with ethanol / water (1:1), and finally vacuum dry at 60℃ for 24h to obtain quaternary ammonium salt intercalated organomontmorillonite;

[0076] (4) 8g of dilauryl thiopropionate (DLTP) and 13g of quaternary ammonium salt-intercalated organomontmorillonite were melt-intercalated at 120°C for 18min to obtain DLTP-loaded organomontmorillonite.

[0077] (5) 105g polypropylene, 13g low-density polyethylene, 13g loaded DLTP organic montmorillonite, 6g intercalated montmorillonite, 5g dicumyl peroxide, 1.5g sulfur, 1.5g polypropylene grafted maleic anhydride and 1.5g polyethylene wax are mixed evenly in a high-speed mixer and then fed into a twin-screw extruder for extrusion granulation to obtain an aging-resistant plastic material. The twin-screw extruder is a co-rotating twin-screw extruder with a screw length-to-diameter ratio of 45. The feed temperature to discharge temperature is: 130℃ for the first section, 170℃ for the second section, 190℃ for the third section, 170℃ for the fourth section and 160℃ for the fifth section.

[0078] The plastic granules obtained in the examples and comparative examples were injection molded to prepare flat test specimens. The injection molding process was as follows: barrel temperature 200℃, nozzle temperature 190℃, screw speed 120rpm, resulting in a sheet with a thickness of 4mm. These specimens were then cut into test specimens with a width of 10mm and a length of 80mm for performance testing.

[0079] Abrasion resistance: According to GB / T6739-2006 (Determination of hardness of paint film by pencil method for paint and varnish), the surface of the test sample was scratched with pencils of different hardness, starting from 3B and gradually increasing the pencil hardness until scratches were made. The test results are shown in Table 1.

[0080] Impact resistance: The impact performance of the test specimens was tested according to GB / T1043.1-2008, "Plastics - Determination of impact properties of simply supported beams - Part 1". The test results are shown in Table 1.

[0081] Anti-aging ability: The experiment was conducted according to GB / T16422.2-2014 "Exposure Test Method for Laboratory Light Sources in Plastics". The xenon arc lamp was filtered using a filter, and the exposure cycle was carried out according to Method A, Cycle No. 1. One cycle consisted of 102 minutes of drying followed by 18 minutes of spraying, with a total irradiation time of 500 hours and a broadband irradiance of 60 W / m². 2 The narrowband irradiance is 0.51 W / m. 2 The black standard temperature was 65℃, and the test chamber temperature was 38℃. The impact strength was tested, and the test results are shown in Table 1.

[0082] Table 1 Performance Test Results

[0083]

[0084] Data analysis, as shown in Table 1, reveals that the aging-resistant plastic of this invention possesses excellent comprehensive performance. Montmorillonite, with its rigid lamellar structure, acts as a physical reinforcing phase, enhancing the surface hardness of the material. Its nanoscale dispersion in the matrix forms a tortuous path, effectively blocking the penetration of oxygen, ultraviolet radiation, and moisture, inhibiting the diffusion rate of photo-oxidative aging reactions. Furthermore, the montmorillonite lamellar structure itself possesses ultraviolet shielding properties, enabling it to work with the loaded antioxidant 1010 and the auxiliary antioxidant DLTP to construct a multi-level defense system. Through synergistic effects, it blocks the oxidation chain reaction, maintaining the mechanical integrity of the material under long-term irradiation. Simultaneously, the intercalation modification with antioxidant 1010 and the functionalized quaternary ammonium salt modification strengthen the interfacial bonding between montmorillonite and the polymer chains, allowing for physical cross-linking or ionic interactions with the polymer chains. This reduces the propagation of microcracks caused by stress concentration, enhances interfacial adhesion, promotes the dissipation of impact energy in the matrix, and prevents rapid crack propagation, thereby ensuring the material exhibits good wear resistance, excellent impact resistance, and anti-aging capabilities.

[0085] The performance comparison between Example 2 and Comparative Examples 1 and 2 shows that the combination of these two modified montmorillonites exhibits superior wear resistance, initial impact strength, and anti-aging properties compared to Comparative Example 1 (without intercalated montmorillonite) and Comparative Example 2 (without organic montmorillonite) which lack a single component. This synergistic effect may stem from the following mechanism: the antioxidant 1010 loaded in the intercalated montmorillonite and DLTP in the organic montmorillonite form a composite antioxidant system. The former inhibits the oxidation chain reaction by capturing free radicals, while the latter synergistically delays material aging by decomposing peroxides. Furthermore, the layered structure of the two modified montmorillonites constructs a multi-level barrier network in the matrix. The antioxidant 1010-loaded montmorillonite with a small interlayer spacing can provide rapid release protection, while the DLTP-loaded organic montmorillonite with a large interlayer spacing is uniformly dispersed in the non-polar matrix, providing long-term sustained-release protection. The difference in interlayer spacing and polarity matching causes the antioxidant to exhibit a dual release mode of "rapid response - continuous protection," forming a synergistic antioxidant protection mechanism.

[0086] The performance comparison between Example 2 and Comparative Example 3 shows that Example 2 is superior to Comparative Example 3 in terms of wear resistance, initial impact strength, and impact strength retention rate after aging. This is mainly because without the intercalation of functionalized quaternary ammonium salt, the interlayer spacing of octadecyltrimethylammonium chloride alone is smaller than that of octadecyltrimethylammonium chloride and functionalized quaternary ammonium salt, which cannot form a synergistic effect with antioxidant 1010 loaded montmorillonite, thus affecting its antioxidant capacity. Without the modification of functionalized quaternary ammonium salt, the interfacial bonding force between the loaded DLTP organomontmorillonite and the matrix is ​​affected, resulting in a decrease in its mechanical strength.

[0087] The performance comparison between Example 2 and Comparative Examples 4 and 5 shows that the addition of 1,3,5-tris(bromomethyl)benzene and 1-bromododecane simultaneously introduces branched structures with benzene rings and long alkyl chains into the functionalized quaternary ammonium salt structure. The rigid benzene ring structure of 1,3,5-tris(bromomethyl)benzene may enhance the interlayer bonding force of montmorillonite through π-π stacking, while its branching characteristics can expand the interlayer spacing. The long-chain alkyl group of 1-bromododecane further improves the interlayer expansion through steric hindrance and enhances compatibility with the polymer matrix, resulting in a more stable dispersion system of DLTP-loaded organomontmorillonite in the matrix, forming a synergistic antioxidant network with antioxidant 1010 in the intercalated montmorillonite. Furthermore, the complete structure of the functionalized quaternary ammonium salt may optimize the loading efficiency of DLTP between montmorillonite layers, not only improving the initial mechanical properties of the material but, more importantly, constructing a more durable anti-aging protection system, enabling the material to maintain superior performance stability under long-term use conditions.

[0088] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. An aging-resistant plastic, characterized in that, It is prepared from the following raw materials in parts by weight: 100-110 parts polypropylene, 10-15 parts low-density polyethylene, 10-15 parts DLTP-loaded organomontmorillonite, 5-7 parts intercalated montmorillonite, 3-7 parts crosslinking agent, 1-2 parts sulfur, 1-2 parts compatibilizer and 1-2 parts lubricant. The intercalated montmorillonite is prepared by solvent intercalation of antioxidant 1010 and nano-montmorillonite in acetone. The preparation steps of the DLTP-loaded organomontmorillonite are as follows: S1: Under a nitrogen atmosphere, 1-vinyl-1,2,4-triazole and p-methoxyphenol were added to anhydrous acetonitrile, cooled to 2-4°C in an ice bath, and then 1,5-dibromopentane was added. The mixture was stirred at room temperature for 12 hours, and then 1,3,5-tris(bromomethyl)benzene and 1-bromododecane were added. The mixture was heated to 60°C and stirred for 10-12 hours. The mixture was then purified by rotary evaporation and vacuum dried to obtain the functionalized quaternary ammonium salt. S2: Add nano-montmorillonite to deionized water to obtain a suspension; separately dissolve octadecyltrimethylammonium chloride and functionalized quaternary ammonium salt in ethanol, stir evenly and add to the suspension, stir for 5-6 hours, centrifuge, purify, and obtain quaternary ammonium salt intercalated organomontmorillonite; S3: Mel-intercalation of dilauryl thiopropionate (DLTP) with quaternary ammonium salt-intercalated organomontmorillonite yields DLTP-loaded organomontmorillonite.

2. The aging-resistant plastic according to claim 1, characterized in that, The polypropylene is Zhejiang Petrochemical K8003; the low-density polyethylene is Zhenhai Refining & Chemical 7050H.

3. The aging-resistant plastic according to claim 1, characterized in that, The crosslinking agent is dicumyl peroxide.

4. The aging-resistant plastic according to claim 1, characterized in that, The compatibilizer is polypropylene grafted with maleic anhydride; the lubricant is one of polyethylene wax and calcium stearate.

5. The aging-resistant plastic according to claim 1, characterized in that, The ratio of antioxidant 1010, acetone, and nano-montmorillonite is 3.6-4.5g:50-80mL:3-3.6g.

6. The aging-resistant plastic according to claim 1, characterized in that, The ratio of 1-vinyl-1,2,4-triazole, p-methoxyphenol, anhydrous acetonitrile, 1,5-dibromopentane, 1,3,5-tris(bromomethyl)benzene, and 1-bromododecane in step S1 is 1.5-2.5g:0.01-0.02g:90-100g:1-2g:0.4-0.5g:0.4-0.5g.

7. The aging-resistant plastic according to claim 1, characterized in that, In step S2, the ratio of nano-montmorillonite, deionized water, octadecyltrimethylammonium chloride, functionalized quaternary ammonium salt, and ethanol is 10-15g:500mL:2-3g:1.5-3g:100-200mL.

8. The aging-resistant plastic according to claim 1, characterized in that, In step S3, the ratio of dilauryl thiopropionate (DLTP) to quaternary ammonium salt-intercalated organomontmorillonite is 5-10g:10-15g.

9. The aging-resistant plastic according to claim 1, characterized in that, The preparation steps are as follows: Polypropylene, low-density polyethylene, DLTP-loaded organomontmorillonite, intercalated montmorillonite, crosslinking agent, sulfur, compatibilizer and lubricant are placed in a high-speed mixer and mixed evenly, and then fed into a twin-screw extruder for extrusion granulation to obtain an aging-resistant plastic material.

10. An application of the aging-resistant plastic according to any one of claims 1-9, characterized in that, It is used in the automotive, electronics, construction, and outdoor packaging industries.

Images