A corrosion-resistant and aging-resistant PVC composite material and its preparation method

Abstract

This invention relates to the field of polymer materials technology, specifically disclosing a corrosion-resistant and aging-resistant PVC composite material and its preparation method. The corrosion-resistant and aging-resistant PVC composite material includes PVC resin, polytetrafluoroethylene, anti-aging additives, imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, filler, plasticizer, and lubricant. The eugenol-epimylochloropropane-gallic acid polyphenol anti-aging additive has a large molecular weight and is not easily migrated or precipitated. It can capture photo-oxidative aging free radicals through a large number of phenolic hydroxyl groups, shield ultraviolet light, and complex corrosive metal ions, effectively inhibiting the photo-oxidative degradation and performance deterioration of PVC. The imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer has the dual functions of inorganic laminations and organic imidazole heterocycles, significantly improving the material's resistance to media corrosion and synergistic aging. The interaction of the components significantly improves the stability and service life of the PVC composite material under complex working conditions such as marine and chemical environments, showing promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to a corrosion-resistant and aging-resistant PVC composite material and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC), as a general-purpose polymer material, possesses outstanding advantages such as excellent mechanical properties, good electrical insulation, chemical corrosion resistance, and low price, and is widely used in building materials, pipes, cable sheaths, packaging, and outdoor facilities. However, the PVC molecular chain contains unstable defect sites such as α-Cl and allyl chloride, which are prone to dehydrochlorination reactions under the influence of light and heat, forming conjugated polyene structures, leading to discoloration and deterioration of mechanical properties. Ultraviolet radiation is the main factor initiating this photodegradation process, causing a significant decrease in the material's impact strength and tensile strength with prolonged aging time. In corrosive environments such as marine or chemical plants, media such as sodium chloride and magnesium chloride in seawater penetrate into the material, increasing free volume and accelerating molecular chain movement, thereby exacerbating the decline in mechanical properties. When photoaging and corrosive media act synergistically, ultraviolet light induces matrix degradation, and corrosive media easily penetrate along microcracks; the interaction between the two accelerates the deterioration of material performance.

[0003] Currently, Chinese patent CN119684725A discloses an anti-aging PVC material, which is compounded with three functional components: 4,4'-thiobis(6-tert-butyl-3-methylphenol), 2-hydroxy-4-n-octyloxybenzophenone, and tris(hydroxymethyl)aminomethane. It relies on multiple synergistic mechanisms of antioxidant scavenging, ultraviolet light energy conversion, and thermal stability protection to improve the photo-thermal aging resistance of PVC. However, it is not suitable for corrosive conditions such as high salt and acid / alkali, and cannot meet the dual requirements of aging resistance and corrosion resistance. In complex outdoor scenarios, the service life of PVC composite materials is still relatively short.

[0004] Based on the above statements, the present invention provides a corrosion-resistant and aging-resistant PVC composite material and its preparation method. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a corrosion-resistant and aging-resistant PVC composite material and its preparation method.

[0006] In a first aspect, the present invention provides a corrosion-resistant and aging-resistant PVC composite material, which adopts the following technical solution:

[0007] A corrosion-resistant and aging-resistant PVC composite material, comprising the following components by weight: 80-120 parts PVC resin, 10-20 parts polytetrafluoroethylene, 8-19 parts anti-aging additives, 5-10 parts imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, 1-5 parts filler, 25-35 parts plasticizer, and 0.5-1 part lubricant.

[0008] Preferably, the anti-aging additive is prepared by the following method:

[0009] Under nitrogen protection, eugenol, epichlorohydrin and tetrabutylammonium bromide are mixed evenly and pre-reacted at 90-100℃ for 4-6 hours. Then, the temperature is lowered to 55-65℃, sodium hydroxide solution is added and the mixture is stirred for 4-6 hours to achieve ring closure. After the reaction is completed, the mixture is washed with distilled water until neutral and then the residual epichlorohydrin is removed by rotary evaporation under reduced pressure to obtain eugenol glycidyl ether.

[0010] Under nitrogen protection, eugenol glycidyl ether and gallic acid were added to anhydrous ethanol and stirred until homogeneous. The pH was adjusted to 8.5-9.5, and the temperature was raised to 60-70℃ for 4-6 hours. After cooling, the mixture was neutralized to neutral with dilute hydrochloric acid, purified by recrystallization, and dried under vacuum to obtain the anti-aging additive.

[0011] Preferably, the ratio of eugenol, epichlorohydrin, gallic acid, tetrabutylammonium bromide, sodium hydroxide solution to anhydrous ethanol is 1 mol:(1-1.2) mol:(1.05-1.25) mol:(0.5-1.5) g:

[0012] (320-350)g:(150-250)mL; the concentration of the sodium hydroxide solution is 40-50wt%.

[0013] Preferably, the imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer is prepared by the following method:

[0014] Magnesium nitrate, zinc nitrate, and aluminum nitrate were dissolved in water and stirred to form a nitrate solution. Imidazole-4,5-dicarboxylic acid was then added to a sodium hydroxide solution to form a mixture. The nitrate solution was placed in a water bath at 70-80°C. After the mixture was added dropwise, the reaction solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 150-170°C for 6-10 hours. After the reaction, the mixture was filtered, washed, and dried to obtain an imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer.

[0015] Preferably, the mass ratio of magnesium nitrate, zinc nitrate, aluminum nitrate, imidazole-4,5-dicarboxylic acid, sodium hydroxide solution to water is 5:(4-6):4:(0.5-1):(18-20):20; and the concentration of the sodium hydroxide solution is 50wt%.

[0016] Preferably, the filler is at least one of nano-silica, nano-titanium dioxide, nano-sepiolite, and halloysite nanotubes.

[0017] Preferably, the plasticizer is at least one selected from trioctyl trimellitate, tributyl citrate, dioctyl phthalate, and di-n-octyl adipate.

[0018] Preferably, the lubricant is at least one of polyethylene wax, paraffin wax, and stearic acid.

[0019] Secondly, the present invention provides a method for preparing a corrosion-resistant and aging-resistant PVC composite material, which adopts the following technical solution:

[0020] A method for preparing a corrosion-resistant and aging-resistant PVC composite material includes the following steps:

[0021] By weight, PVC resin, polytetrafluoroethylene, anti-aging additives, imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, filler, plasticizer, and lubricant are mixed evenly. The mixture is then melt-extruded and cooled to form a PVC composite material that is corrosion-resistant and aging-resistant.

[0022] Preferably, the melt extrusion is provided with four temperature control zones, with the temperatures from the feeding section to the die section being zone 1 (160-170℃), zone 2 (170-180℃), zone 3 (180-190℃), and zone 4 (185-195℃).

[0023] In summary, the present invention has the following beneficial effects:

[0024] 1. The corrosion-resistant and aging-resistant PVC composite material of the present invention includes PVC resin, polytetrafluoroethylene, anti-aging additives, imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, filler, plasticizer, and lubricant. The components interact with each other to significantly improve the stability and service life of the PVC composite material under complex working conditions such as marine and chemical industries.

[0025] 2. The anti-aging additive of this invention uses epichlorohydrin as a bridging unit to covalently link eugenol and gallic acid, exhibiting excellent long-term protection against aging and corrosion. The anti-aging additive contains phenolic hydroxyl groups, which can capture free radicals that degrade PVC photo-oxidation, terminate the dehydrochlorination chain reaction, stabilize defect sites in the PVC molecular chain, and inhibit yellowing and mechanical degradation of the substrate. The benzene ring conjugated structure can shield ultraviolet light, reducing damage from photochain breakage. Its multi-hydroxyl structure can also chelate corrosive metal ions, inhibiting matrix free volume expansion and interfacial debonding caused by salt media penetration. Simultaneously, this anti-aging additive has a low migration and precipitation rate and strong stability, reducing the formation of photo-aging microcracks and hindering the diffusion of corrosive media, effectively breaking the synergistic degradation mechanism of photo-aging and corrosion, and significantly improving the stability of PVC in complex outdoor working conditions.

[0026] 3. The imidazole dicarboxylic acid intercalated magnesium-aluminum-zinc heat stabilizer of the present invention has magnesium-aluminum-zinc layers that can efficiently adsorb and neutralize hydrogen chloride generated by the photothermal degradation of PVC, inhibiting the thermal aging chain reaction; the interlayer imidazole five-membered heterocycles can chelate corrosive metal cations, avoiding matrix volume expansion and interface debonding caused by ion enrichment; at the same time, a dense interface structure is formed through hydrogen bonding, preventing the generation of micro-cracks and the penetration of corrosive media. The imidazole rings can neutralize acidic corrosive substances, and their conjugated structure can capture photo-oxidative aging free radicals, inhibiting the generation and propagation of matrix microcracks and blocking the diffusion channels of corrosive media. In addition, the layered structure can form a physical barrier to slow down the intrusion of light, heat, oxygen and corrosive media, and the organic intercalated ligands can also improve the compatibility between the filler and the PVC matrix, effectively improving the long-term thermal stability, weather resistance and corrosion resistance of the composite material.

[0027] 4. The anti-aging additive and imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer of the present invention can be combined to form a synergistic protection system, which can jointly improve the overall performance of PVC composite materials and make their application range wider. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the embodiments.

[0029] Unless otherwise specified, all materials and reagents used in this invention are commercially available. Specifically, PVC resin (CAS No. 9002-86-2, solid powder) was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.; polytetrafluoroethylene (CAS No. 9002-84-0, solid powder) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; eugenol (CAS No. 97-53-0) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; gallic acid (CAS No. 149-91-7) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; and imidazole-4,5-dicarboxylic acid (CAS No. 570-22-9) was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0030] Examples 1-3 provide a corrosion-resistant and aging-resistant PVC composite material and its preparation method.

[0031] Example 1

[0032] A corrosion-resistant and aging-resistant PVC composite material comprises the following components in parts by weight: 80 parts PVC resin, 10 parts polytetrafluoroethylene, 8 parts anti-aging additive, 5 parts imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, 1 part filler, 25 parts plasticizer, and 0.5 parts lubricant.

[0033] The anti-aging additive was prepared by the following method: Under nitrogen protection, 1 mol of eugenol, 1 mol of epichlorohydrin and 0.5 g of tetrabutylammonium bromide were mixed evenly, pre-reacted at 90℃ for 6 h, then cooled to 55℃, and 320 g of sodium hydroxide solution (concentration of 40 wt%) was added and stirred for 6 h to achieve ring closure. After the reaction was completed, the mixture was washed with distilled water until neutral, and residual epichlorohydrin was removed by rotary evaporation under reduced pressure to obtain eugenol glycidyl ether. Under nitrogen protection, eugenol glycidyl ether and 1.05 mol of gallic acid were added to 150 mL of anhydrous ethanol and stirred evenly. The pH was adjusted to 8.5, and the temperature was raised to 60℃ for 6 h. After cooling, the mixture was neutralized to neutral with dilute hydrochloric acid, purified by recrystallization, and dried under vacuum to obtain the anti-aging additive.

[0034] The imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer is prepared by the following method: 50g of magnesium nitrate, 50g of zinc nitrate and 40g of aluminum nitrate are dissolved in 200g of water and stirred to form a nitrate solution; then 5g of imidazole-4,5-dicarboxylic acid is added to 180g of sodium hydroxide solution (concentration of 50wt%) to form a mixture; the nitrate solution is placed in a water bath at 70℃, and the mixture is added dropwise. After the addition is completed within 1 hour, the reaction solution is transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 150℃ for 10 hours. After the reaction, the mixture is filtered, washed and dried to obtain the imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer.

[0035] The filler is nano-silica; the plasticizer is trioctyl trimellitate; and the lubricant is polyethylene wax.

[0036] A method for preparing a corrosion-resistant and aging-resistant PVC composite material includes the following steps:

[0037] By weight, PVC resin, polytetrafluoroethylene, anti-aging additives, imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, filler, plasticizer, and lubricant are mixed evenly. The mixture is then melt-extruded and cooled to form a mold. The melt extrusion process is set with four temperature control zones. The temperatures from the feeding section to the die head section are 160℃ in zone 1, 170℃ in zone 2, 180℃ in zone 3, and 185℃ in zone 4, respectively, to obtain a corrosion-resistant and aging-resistant PVC composite material.

[0038] Example 2

[0039] A corrosion-resistant and aging-resistant PVC composite material comprises the following components in parts by weight: 100 parts PVC resin, 15 parts polytetrafluoroethylene, 15 parts anti-aging additive, 8 parts imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, 3 parts filler, 30 parts plasticizer, and 0.8 parts lubricant.

[0040] The anti-aging additive was prepared by the following method: Under nitrogen protection, 1 mol of eugenol, 1.1 mol of epichlorohydrin and 1.1 g of tetrabutylammonium bromide were mixed evenly and pre-reacted at 95℃ for 4-6 h. Then, the temperature was lowered to 60℃, and 340 g of sodium hydroxide solution (concentration of 40 wt%) was added and stirred for 5 h to achieve ring closure. After the reaction was completed, the mixture was washed with distilled water until neutral and the residual epichlorohydrin was removed by rotary evaporation under reduced pressure to obtain eugenol glycidyl ether. Under nitrogen protection, eugenol glycidyl ether and 1.15 mol of gallic acid were added to 200 mL of anhydrous ethanol and stirred evenly. The pH was adjusted to 9, and the temperature was raised to 65℃ for 5 h. After cooling, the mixture was neutralized with dilute hydrochloric acid. After recrystallization purification and vacuum drying, the anti-aging additive was obtained.

[0041] The imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer is prepared by the following method: 50g of magnesium nitrate, 60g of zinc nitrate and 40g of aluminum nitrate are dissolved in 200g of water and stirred to form a nitrate solution; then 7g of imidazole-4,5-dicarboxylic acid is added to 200g of sodium hydroxide solution (concentration of 50wt%) to form a mixture; the nitrate solution is placed in a water bath at 75℃, and the mixture is added dropwise. After the addition is completed within 1 hour, the reaction solution is transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 160℃ for 8 hours. After the reaction, the mixture is filtered, washed and dried to obtain the imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer.

[0042] The filler is nano-titanium dioxide; the plasticizer is tributyl citrate; and the lubricant is paraffin wax.

[0043] A method for preparing a corrosion-resistant and aging-resistant PVC composite material includes the following steps:

[0044] By weight, PVC resin, polytetrafluoroethylene, anti-aging additives, imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, filler, plasticizer, and lubricant are mixed evenly. The mixture is then melt-extruded and cooled to form a mold. The melt extrusion process is set with four temperature control zones. The temperatures from the feeding section to the die head section are 165℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3, and 190℃ in zone 4, respectively, to obtain a corrosion-resistant and aging-resistant PVC composite material.

[0045] Example 3

[0046] A corrosion-resistant and aging-resistant PVC composite material comprises the following components in parts by weight: 120 parts PVC resin, 20 parts polytetrafluoroethylene, 19 parts anti-aging additives, 10 parts imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, 5 parts filler, 35 parts plasticizer, and 1 part lubricant.

[0047] The anti-aging additive was prepared by the following method: Under nitrogen protection, 1 mol of eugenol, 1.2 mol of epichlorohydrin and 1.5 g of tetrabutylammonium bromide were mixed evenly, pre-reacted at 100℃ for 4 h, then cooled to 65℃, and 350 g of sodium hydroxide solution (concentration of 40 wt%) was added and stirred for 4 h to achieve ring closure. After the reaction was completed, the mixture was washed with distilled water until neutral, and residual epichlorohydrin was removed by rotary evaporation under reduced pressure to obtain eugenol glycidyl ether. Under nitrogen protection, eugenol glycidyl ether and 1.25 mol of gallic acid were added to 250 mL of anhydrous ethanol and stirred evenly. The pH was adjusted to 9.5, and the temperature was raised to 70℃ for 4 h. After cooling, the mixture was neutralized to neutral with dilute hydrochloric acid, purified by recrystallization, and dried under vacuum to obtain the anti-aging additive.

[0048] The imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer is prepared by the following method: 50g of magnesium nitrate, 40g of zinc nitrate and 40g of aluminum nitrate are dissolved in 200g of water and stirred to form a nitrate solution; then 10g of imidazole-4,5-dicarboxylic acid is added to 200g of sodium hydroxide solution (concentration of 50wt%) to form a mixture; the nitrate solution is placed in a water bath at 80℃, and the mixture is added dropwise. After the addition is completed within 1 hour, the reaction solution is transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 170℃ for 6 hours. After the reaction, the mixture is filtered, washed and dried to obtain the imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer.

[0049] The filler is nano-sepiolite; the plasticizer is dioctyl phthalate; and the lubricant is stearic acid.

[0050] A method for preparing a corrosion-resistant and aging-resistant PVC composite material includes the following steps:

[0051] By weight, PVC resin, polytetrafluoroethylene, anti-aging additives, imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, filler, plasticizer, and lubricant are mixed evenly. The mixture is then melt-extruded and cooled to form a mold. The melt extrusion process is set with four temperature control zones. The temperatures from the feeding section to the die head section are 170℃ in zone 1, 180℃ in zone 2, 190℃ in zone 3, and 195℃ in zone 4, respectively, to obtain a corrosion-resistant and aging-resistant PVC composite material.

[0052] To verify the performance of the corrosion-resistant and aging-resistant PVC composite materials obtained in Examples 1-3 of this invention, comparative examples 1-4 were set up.

[0053] Comparative Example 1

[0054] Comparative Example 1 differs from Example 1 in that the anti-aging agent is obtained by mixing eugenol and gallic acid in a molar ratio of 1:1, as detailed below:

[0055] A corrosion-resistant and aging-resistant PVC composite material comprises the following components in parts by weight: 80 parts PVC resin, 10 parts polytetrafluoroethylene, 8 parts anti-aging additive, 5 parts imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, 1 part filler, 25 parts plasticizer, and 0.5 parts lubricant.

[0056] The anti-aging additive is obtained by mixing eugenol and gallic acid in a molar ratio of 1:1.

[0057] The imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer is prepared by the following method: 50g of magnesium nitrate, 50g of zinc nitrate and 40g of aluminum nitrate are dissolved in 200g of water and stirred to form a nitrate solution; then 5g of imidazole-4,5-dicarboxylic acid is added to 180g of sodium hydroxide solution (concentration of 50wt%) to form a mixture; the nitrate solution is placed in a water bath at 70℃, and the mixture is added dropwise. After the addition is completed within 1 hour, the reaction solution is transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 150℃ for 10 hours. After the reaction, the mixture is filtered, washed and dried to obtain the imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer.

[0058] The filler is nano-silica; the plasticizer is trioctyl trimellitate; and the lubricant is polyethylene wax.

[0059] A method for preparing a corrosion-resistant and aging-resistant PVC composite material includes the following steps:

[0060] By weight, PVC resin, polytetrafluoroethylene, anti-aging additives, imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, filler, plasticizer, and lubricant are mixed evenly. The mixture is then melt-extruded and cooled to form a mold. The melt extrusion process is set with four temperature control zones. The temperatures from the feeding section to the die head section are 160℃ in zone 1, 170℃ in zone 2, 180℃ in zone 3, and 185℃ in zone 4, respectively, to obtain a corrosion-resistant and aging-resistant PVC composite material.

[0061] Comparative Example 2

[0062] Comparative Example 2 differs from Example 1 in that an equal mass of sarcosine-intercalated magnesium-aluminum-zinc heat stabilizer is used instead of imidazole dicarboxylic acid-intercalated magnesium-aluminum-zinc heat stabilizer, as detailed below:

[0063] A corrosion-resistant and aging-resistant PVC composite material comprises the following components in parts by weight: 80 parts PVC resin, 10 parts polytetrafluoroethylene, 8 parts anti-aging additives, 5 parts sarcosine intercalated magnesium aluminum zinc heat stabilizer, 1 part filler, 25 parts plasticizer, and 0.5 parts lubricant.

[0064] The anti-aging additive was prepared by the following method: Under nitrogen protection, 1 mol of eugenol, 1 mol of epichlorohydrin and 0.5 g of tetrabutylammonium bromide were mixed evenly, pre-reacted at 90℃ for 6 h, then cooled to 55℃, and 320 g of sodium hydroxide solution (concentration of 40 wt%) was added and stirred for 6 h to achieve ring closure. After the reaction was completed, the mixture was washed with distilled water until neutral, and residual epichlorohydrin was removed by rotary evaporation under reduced pressure to obtain eugenol glycidyl ether. Under nitrogen protection, eugenol glycidyl ether and 1.05 mol of gallic acid were added to 150 mL of anhydrous ethanol and stirred evenly. The pH was adjusted to 8.5, and the temperature was raised to 60℃ for 6 h. After cooling, the mixture was neutralized to neutral with dilute hydrochloric acid, purified by recrystallization, and dried under vacuum to obtain the anti-aging additive.

[0065] A sarcosine-intercalated magnesium-aluminum-zinc heat stabilizer was prepared by the following method: 50g of magnesium nitrate, 50g of zinc nitrate, and 40g of aluminum nitrate were dissolved in 200g of water and stirred to form a nitrate solution; then 5g of sarcosine was added to 180g of sodium hydroxide solution (concentration of 50wt%) to form a mixture; the nitrate solution was placed in a 70℃ water bath, and the mixture was added dropwise. After the addition was completed within 1 hour, the reaction solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 150℃ for 10 hours. After the reaction, the mixture was filtered, washed, and dried to obtain the sarcosine-intercalated magnesium-aluminum-zinc heat stabilizer.

[0066] The filler is nano-silica; the plasticizer is trioctyl trimellitate; and the lubricant is polyethylene wax.

[0067] A method for preparing a corrosion-resistant and aging-resistant PVC composite material includes the following steps:

[0068] By weight, PVC resin, polytetrafluoroethylene, anti-aging additives, sarcosine intercalated magnesium aluminum zinc heat stabilizer, filler, plasticizer, and lubricant are mixed evenly. The mixture is then melt-extruded and cooled to form a mold. The melt extrusion process is set with four temperature control zones. The temperatures from the feeding section to the die head section are 160℃ in zone 1, 170℃ in zone 2, 180℃ in zone 3, and 185℃ in zone 4, respectively, to obtain a corrosion-resistant and aging-resistant PVC composite material.

[0069] Comparative Example 3

[0070] Comparative Example 3 differs from Example 1 in that an equal mass of anti-aging additive is used to replace the imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, as detailed below:

[0071] A corrosion-resistant and aging-resistant PVC composite material comprises the following components in parts by weight: 80 parts PVC resin, 10 parts polytetrafluoroethylene, 13 parts anti-aging additives, 1 part filler, 25 parts plasticizer, and 0.5 parts lubricant.

[0072] The anti-aging additive was prepared by the following method: Under nitrogen protection, 1 mol of eugenol, 1 mol of epichlorohydrin and 0.5 g of tetrabutylammonium bromide were mixed evenly, pre-reacted at 90℃ for 6 h, then cooled to 55℃, and 320 g of sodium hydroxide solution (concentration of 40 wt%) was added and stirred for 6 h to achieve ring closure. After the reaction was completed, the mixture was washed with distilled water until neutral, and residual epichlorohydrin was removed by rotary evaporation under reduced pressure to obtain eugenol glycidyl ether. Under nitrogen protection, eugenol glycidyl ether and 1.05 mol of gallic acid were added to 150 mL of anhydrous ethanol and stirred evenly. The pH was adjusted to 8.5, and the temperature was raised to 60℃ for 6 h. After cooling, the mixture was neutralized to neutral with dilute hydrochloric acid, purified by recrystallization, and dried under vacuum to obtain the anti-aging additive.

[0073] The filler is nano-silica; the plasticizer is trioctyl trimellitate; and the lubricant is polyethylene wax.

[0074] A method for preparing a corrosion-resistant and aging-resistant PVC composite material includes the following steps:

[0075] By weight, PVC resin, polytetrafluoroethylene, anti-aging additives, fillers, plasticizers, and lubricants are mixed evenly. The mixture is then melt-extruded and cooled to form a mold. The melt extrusion process is set with four temperature control zones. The temperatures from the feeding section to the die head section are 160℃ in zone 1, 170℃ in zone 2, 180℃ in zone 3, and 185℃ in zone 4, respectively, to obtain a corrosion-resistant and aging-resistant PVC composite material.

[0076] Comparative Example 4

[0077] Comparative Example 4 differs from Example 1 in that an equal mass of imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer is used to replace the anti-aging additive, as detailed below:

[0078] A corrosion-resistant and aging-resistant PVC composite material comprises the following components in parts by weight: 80 parts PVC resin, 10 parts polytetrafluoroethylene, 13 parts imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, 1 part filler, 25 parts plasticizer, and 0.5 parts lubricant.

[0079] The imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer is prepared by the following method: 50g of magnesium nitrate, 50g of zinc nitrate and 40g of aluminum nitrate are dissolved in 200g of water and stirred to form a nitrate solution; then 5g of imidazole-4,5-dicarboxylic acid is added to 180g of sodium hydroxide solution (concentration of 50wt%) to form a mixture; the nitrate solution is placed in a water bath at 70℃, and the mixture is added dropwise. After the addition is completed within 1 hour, the reaction solution is transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 150℃ for 10 hours. After the reaction, the mixture is filtered, washed and dried to obtain the imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer.

[0080] The filler is nano-silica; the plasticizer is trioctyl trimellitate; and the lubricant is polyethylene wax.

[0081] A method for preparing a corrosion-resistant and aging-resistant PVC composite material includes the following steps:

[0082] By weight, PVC resin, polytetrafluoroethylene, imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, filler, plasticizer, and lubricant are mixed evenly. The mixture is then melt-extruded and cooled to form a mold. The melt extrusion process is set with four temperature control zones. The temperatures from the feeding section to the die head section are 160℃ in zone 1, 170℃ in zone 2, 180℃ in zone 3, and 185℃ in zone 4, respectively, to obtain a corrosion-resistant and aging-resistant PVC composite material.

[0083] The corrosion-resistant and aging-resistant PVC composite materials obtained in Examples 1-3 and Comparative Examples 1-4 of this invention were subjected to performance tests, and the results are shown in Table 1:

[0084] Tensile strength and elongation at break were tested according to GB / T 1040.2-2022 "Determination of tensile properties of plastics - Part 2: Test conditions for molding and extrusion plastics"; thermal stability time was tested according to GB / T 2917.1-2002 "Determination of the release of hydrogen chloride and any other acidic products at high temperature from blends and products mainly composed of vinyl chloride homopolymers and copolymers - Congo red method"; UV aging yellowing index was tested according to GB / T 16422.3-2014 "Laboratory light source exposure test method for plastics - Part 3: Fluorescent ultraviolet lamp" with an aging time of 2000h, and the yellowing index ΔE was calculated using the CIE LAB color space; the tensile strength retention rate after 14 days of UV aging was still based on GB / T 16422.3-2014, and the tensile strength was retested after 14 days of UV irradiation, and the retention rate (%) was calculated by comparing the tensile strength with the initial strength; salt spray corrosion test was conducted according to GB / T According to 10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test", the corrosion time was set to 168 hours (7 days). The sample mass loss rate was calculated, and the specific results are shown in Table 1.

[0085] Table 1:

[0086] Tensile strength / MPa Elongation at break / % Thermal stability time / min 2000h UV aging yellowing index ΔE UV aging 14d intensity retention rate / % Salt spray 7-day mass loss rate / % Example 1 28.6 248 88.2 2.63 93.3 0.28 Example 2 30.4 265 93.5 2.95 96.7 0.22 Example 3 31.2 272 96.8 2.52 94.2 0.19 Comparative Example 1 25.1 210 64.6 4.14 76.5 0.65 Comparative Example 2 26.3 224 60.3 3.58 80.1 0.51 Comparative Example 3 24.8 206 57.1 3.92 78.6 0.58 Comparative Example 4 25.7 218 70.4 4.68 73.8 0.72

[0087] As shown in the table above, the tensile strength, elongation at break, and thermal stability time of the PVC composite materials prepared in Examples 1-3 of this invention increase sequentially. The yellowing index after 2000 hours of UV aging is less than 3, the mass loss rate after 7 days of salt spray is no higher than 0.28%, and the strength retention rate after 14 days of UV aging is over 93%. All properties are significantly better than those of Comparative Examples 1-4, which fully demonstrates that the anti-aging additive and imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer compound system of this invention can synergistically enhance the mechanical properties, long-term thermal stability, UV aging resistance, and salt corrosion resistance of the material. The anti-aging additive is not easily migrated or lost, and the mechanical properties are retained at a high rate after aging. It is suitable for complex corrosive outdoor working conditions such as marine and chemical industries and has broad application prospects.

[0088] Comparing Example 1 and Comparative Example 1, it can be seen that the anti-aging additive of the present invention is not easily migrated. Compared with simple physical blending additives, it can more effectively improve the thermal stability, UV resistance, and salt corrosion resistance of PVC, and has a higher mechanical retention rate after aging. Comparing Example 1 and Comparative Example 2, it can be seen that the imidazole dicarboxylic acid intercalated magnesium aluminum zinc stabilizer is more effective than the sarcosine intercalated magnesium aluminum zinc stabilizer in terms of thermal stability, corrosion inhibition, and mechanical retention after aging. Comparing Example 1 and Comparative Example 3, it can be seen that the thermal stability and corrosion resistance of the material are significantly reduced when the imidazole intercalated magnesium aluminum zinc stabilizer is missing. Comparing Example 1 and Comparative Example 4, it can be seen that the weather resistance, anti-aging properties, and mechanical retention properties of the material are greatly weakened when the anti-aging additive is missing. In summary, the combination of the two types of additives forms a synergistic protection system, which can significantly improve the durability of PVC composite materials.

[0089] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A corrosion-resistant and aging-resistant PVC composite material, characterized in that, It includes the following components by weight: 80-120 parts PVC resin, 10-20 parts polytetrafluoroethylene, 8-19 parts anti-aging additive, 5-10 parts imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, 1-5 parts filler, 25-35 parts plasticizer, and 0.5-1 part lubricant.

2. The corrosion-resistant and aging-resistant PVC composite material according to claim 1, characterized in that, The anti-aging additive is prepared by the following method: Under nitrogen protection, eugenol, epichlorohydrin and tetrabutylammonium bromide are mixed evenly and pre-reacted at 90-100℃ for 4-6 hours. Then, the temperature is lowered to 55-65℃, sodium hydroxide solution is added and the mixture is stirred for 4-6 hours to achieve ring closure. After the reaction is completed, the mixture is washed with distilled water until neutral and then the residual epichlorohydrin is removed by rotary evaporation under reduced pressure to obtain eugenol glycidyl ether. Under nitrogen protection, eugenol glycidyl ether and gallic acid were added to anhydrous ethanol and stirred until homogeneous. The pH was adjusted to 8.5-9.5, and the temperature was raised to 60-70℃ for 4-6 hours. After cooling, the mixture was neutralized to neutral with dilute hydrochloric acid, purified by recrystallization, and dried under vacuum to obtain the anti-aging additive.

3. The corrosion-resistant and aging-resistant PVC composite material according to claim 2, characterized in that, The ratio of eugenol, epichlorohydrin, gallic acid, tetrabutylammonium bromide, sodium hydroxide solution, and anhydrous ethanol is 1 mol:(1-1.2) mol:(1.05-1.25) mol:(0.5-1.5) g:(320-350) g: (150-250) mL; the concentration of the sodium hydroxide solution is 40-50 wt%.

4. The corrosion-resistant and aging-resistant PVC composite material according to claim 1, characterized in that, The imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer is prepared by the following method: Magnesium nitrate, zinc nitrate, and aluminum nitrate were dissolved in water and stirred to form a nitrate solution. Imidazole-4,5-dicarboxylic acid was then added to a sodium hydroxide solution to form a mixture. The nitrate solution was placed in a water bath at 70-80°C. After the mixture was added dropwise, the reaction solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 150-170°C for 6-10 hours. After the reaction, the mixture was filtered, washed, and dried to obtain an imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer.

5. The corrosion-resistant and aging-resistant PVC composite material according to claim 4, characterized in that, The mass ratio of magnesium nitrate, zinc nitrate, aluminum nitrate, imidazole-4,5-dicarboxylic acid, sodium hydroxide solution, and water is 5:(4-6):4:(0.5-1):(18-20):20; the concentration of the sodium hydroxide solution is 50wt%.

6. The corrosion-resistant and aging-resistant PVC composite material according to claim 1, characterized in that, The filler is at least one of nano-silica, nano-titanium dioxide, nano-sepiolite, and halloysite nanotubes.

7. The corrosion-resistant and aging-resistant PVC composite material according to claim 1, characterized in that, The plasticizer is at least one of trioctyl trimellitate, tributyl citrate, dioctyl phthalate, and di-n-octyl adipate.

8. The corrosion-resistant and aging-resistant PVC composite material according to claim 1, characterized in that, The lubricant is at least one of polyethylene wax, paraffin wax, and stearic acid.

9. A method for preparing a corrosion-resistant and aging-resistant PVC composite material according to any one of claims 1-8, characterized in that, Includes the following steps: By weight, PVC resin, polytetrafluoroethylene, anti-aging additives, imidazole dicarboxylic acid intercalated magnesium aluminum zinc heat stabilizer, filler, plasticizer, and lubricant are mixed evenly. The mixture is then melt-extruded and cooled to form a PVC composite material that is corrosion-resistant and aging-resistant.

10. The method for preparing the corrosion-resistant and aging-resistant PVC composite material according to claim 9, characterized in that, The melt extrusion is equipped with four temperature control zones, with the temperatures from the feeding section to the die section being 160-170℃ in zone one, 170-180℃ in zone two, 180-190℃ in zone three, and 185-195℃ in zone four.