Lead and arsenic-free polyvinyl chloride sheathed cable material and preparation method thereof

Abstract

The invention relates to the technical field of polyvinyl chloride materials, and discloses a lead and arsenic-free polyvinyl chloride sheath cable material and a preparation method thereof. The polyvinyl chloride sheathed cable material comprises the following raw material components in parts by weight: 100 parts of polyvinyl chloride resin powder, 40-45 parts of a plasticizer, 5-7 parts of a stabilizer, 10-15 parts of calcium carbonate, 10-15 parts of aluminum hydroxide, 2-4 parts of magnesium hydroxide, 0.5-2 parts of an anti-dripping agent and 0.2-1 part of a synergist, the stabilizer is folic acid modified Ca-Mg-Al-LDH (layered double hydroxide). The plasticizer is composed of dioctyl terephthalate and stearoyl chloride modified red phosphorus microcapsules. The prepared polyvinyl chloride sheathed cable material has good flame retardance and heat aging resistance.

Description

Technical Field

[0001] This invention relates to the field of polyvinyl chloride (PVC) materials technology, and discloses a lead- and arsenic-free PVC sheathed cable material and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) materials possess excellent insulation, chemical stability, and ease of processing, making them widely used in cable sheathing materials, especially in mining cable sheathing materials. Mining cable sheathing materials are typically rated for 70°C to meet the operating temperature requirements of underground mines. Previously, PVC sheathed cable materials for this condition generally incorporated lead and arsenic to improve flame retardancy and because lead salts can capture HCl, inhibit decomposition, and improve thermal stability. However, with the implementation of GB / T43069-2023 in April 2025, which requires limits on the lead and arsenic content of cable materials (lead content should not exceed 1000 mg / kg, and arsenic content should not exceed 1000 mg / kg), common cable materials can no longer meet the national standard requirements. Therefore, a lead- and arsenic-free PVC sheathed cable material is needed.

[0003] However, existing PVC sheathed cable materials without lead and arsenic have the following problems: First, the flame retardant performance needs to be improved. Second, the ambient temperature fluctuates greatly in mining environments. PVC sheathed materials with a temperature of 70℃ are easily affected by high temperatures and undergo aging and degradation during long-term use, leading to a decrease in material strength and a reduction in flame retardant performance. This can then lead to safety accidents such as cable short circuits and leakage, seriously threatening the safety of mine production.

[0004] In summary, researching a lead- and arsenic-free PVC sheathed cable material with excellent flame retardancy and stable heat aging resistance has significant practical importance and industrial application value. Summary of the Invention

[0005] The purpose of this invention is to provide a lead- and arsenic-free polyvinyl chloride sheathed cable material and its preparation method, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A lead- and arsenic-free polyvinyl chloride (PVC) sheathed cable material, wherein the raw materials of the PVC sheathed cable material include the following components by weight: 100 parts of PVC resin powder, 40-45 parts of plasticizer, 5-7 parts of stabilizer, 10-15 parts of calcium carbonate, 10-15 parts of aluminum hydroxide, 2-4 parts of magnesium hydroxide, 0.5-2 parts of anti-drip agent, and 0.2-1 parts of synergist;

[0008] The stabilizer is folic acid-modified Ca-Mg-Al-LDH.

[0009] In a further embodiment, the method for preparing the folic acid-modified Ca-Mg-Al-LDH is as follows:

[0010] (1) Add calcium nitrate, magnesium nitrate and aluminum nitrate to water and stir to dissolve to obtain a salt solution; use the double drop coprecipitation method to add cyanuric acid aqueous solution and alkaline solution dropwise at the same time, control the pH of the alkaline solution to 9~10, stir for 6~8 hours; hydrothermally react at 160~170℃ for 10~12 hours, wash and dry to obtain Ca-Mg-Al-LDH;

[0011] (2) Disperse folic acid and Ca-Mg-Al-LDH separately in water, then mix them, ultrasonically disperse for 30-60 minutes, centrifuge and dry to obtain folic acid modified Ca-Mg-Al-LDH.

[0012] In a further embodiment, the raw material for Ca-Mg-Al-LDH includes the following components: 0.6-0.7 parts calcium nitrate, 6-7 parts magnesium nitrate, 2-3 parts aluminum nitrate, and 3-4 parts cyanuric acid;

[0013] In the raw material for folic acid-modified Ca-Mg-Al-LDH, the mass ratio of folic acid to Ca-Mg-Al-LDH is 1~2:5.

[0014] In a further embodiment, the plasticizer is composed of dioctyl terephthalate and stearoyl chloride-modified red phosphorus microcapsules in a mass ratio of 35~38:5~7.

[0015] In a further embodiment, the preparation method of the stearoyl chloride-modified red phosphorus microcapsules includes the following steps:

[0016] (1) Add red phosphorus and melamine to water, add boric acid and sodium hexametaphosphate, heat to 75~80℃ and stir for 4~5h, cool to 40~45℃ and continue stirring for 3~4h, vacuum filter and dry to obtain red phosphorus core;

[0017] (2) Add β-cyclodextrin to pyridine and stir at 70-80℃ for 1-2 hours to obtain β-cyclodextrin solution; add red phosphorus core and surfactant to pyridine and stir evenly; add β-cyclodextrin solution dropwise at 70-80℃ and stir for 1-2 hours; add diisocyanate and continue stirring for 10-12 hours to form a shell; filter, wash and dry to obtain red phosphorus microcapsules;

[0018] (3) Disperse the red phosphorus microcapsules in acetone, add alkaline solution under ice bath to control the pH to 8~8.5, slowly add stearoyl chloride and stir for 0.5~1 hour to adjust to neutral, wash and dry to obtain stearoyl chloride modified red phosphorus microcapsules.

[0019] In a further embodiment, the raw materials for the red phosphorus core include the following components: by weight, 18-25 parts red phosphorus, 3-4 parts melamine, 1-3 parts boric acid, 0.1-0.3 parts sodium hexametaphosphate, and 150-180 parts water;

[0020] The raw materials for the red phosphorus microcapsules include the following components: by weight, 5-6 parts β-cyclodextrin, 20-25 parts red phosphorus core, and 6-8 parts diisocyanate;

[0021] The raw materials for the stearoyl chloride-modified red phosphorus microcapsules include red phosphorus microcapsules and stearoyl chloride in a mass ratio of 10:0.2~0.4.

[0022] In a further embodiment, the polyvinyl chloride powder is one or both of SG3 and SG5; the anti-drip agent is polytetrafluoroethylene; and the synergist is barium stearate.

[0023] In a further step, polyvinyl chloride resin powder, plasticizer, stabilizer, calcium carbonate, aluminum hydroxide, magnesium hydroxide, anti-drip agent, and synergist are mixed evenly and then extruded and granulated at 130~160℃ to obtain polyvinyl chloride sheathed cable material.

[0024] Compared with existing technologies, the beneficial effects are as follows:

[0025] The proposed solution uses folic acid-modified layered double hydroxides as stabilizers to avoid the environmental pollution and thermal stability issues associated with lead and arsenic compounds. The folic acid-modified layered double hydroxides are prepared by introducing cyanurate-intercalated double hydroxides (Ca-Mg-Al-LDH) as a base, and then combining folic acid and LDH through hydrogen bonding. Specifically, the intermolecular interaction between folic acid and the Cl bond in PVC improves the compatibility of Ca-Mg-Al-LDH with PVC. Simultaneously, chlorine participates in intermolecular bonding, reducing surface free chlorine and fundamentally inhibiting the thermal dehydrochlorination degradation reaction of PVC, thus improving the material's heat resistance. Furthermore, Ca-Mg-Al-LDH itself contains multiple metals, which enhance Cl coordination and acid neutralization capabilities, inhibiting the PVC degradation cascade reaction and further improving heat resistance. Additionally, the nitrogen-containing groups of the cyanurate intercalation can capture free radicals generated during PVC thermal degradation, improving thermal stability. In addition, it also possesses flame-retardant properties. The metal oxides and char layers formed after its decomposition enhance the density and heat insulation of the char layer, further strengthening the flame-retardant properties of the material. It should be noted that the addition of folic acid-modified layered double hydroxides needs to be limited; excessive addition will hinder dispersion and affect performance.

[0026] In this formulation, the plasticizer consists of red phosphorus microcapsules modified with dioctyl terephthalate and stearoyl chloride. The stearoyl chloride-modified red phosphorus microcapsules function as both an organic flame retardant and an auxiliary plasticizer. A coating process is used to first obtain the red phosphorus microcapsules, improving the compatibility between red phosphorus and PVC and avoiding uneven flame retardant effects caused by red phosphorus agglomeration. A synergistic organic flame retardant of boron, phosphorus, and nitrogen is used, which, along with calcium carbonate, aluminum hydroxide, and magnesium hydroxide, produces a synergistic flame retardant effect. During this process, magnesium hydroxide and aluminum hydroxide first undergo endothermic decomposition, slowing the combustion process and lowering the combustion temperature. The red phosphorus microcapsules then form a dense physical barrier during heating, blocking oxygen and heat transfer, effectively ensuring flame retardancy. Furthermore, stearoyl chloride is used to modify the microcapsules, further improving their dispersibility in PVC. The long chains they contain can form an interpenetrating plasticizing network with dioctyl terephthalate, enhancing the stability of the plasticizing system and reducing DOTP migration and loss; effectively improving the inherent lack of toughness in PVC. However, the amount of stearic acid chloride added needs to be limited. Introducing too much long chain will weaken the interaction between PVC molecular chains, leading to a decline in material properties. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that all raw materials involved in this invention are commercially available unless otherwise specified.

[0029] Implementation Method 1: Step 1: By weight, (1) 0.63 parts calcium nitrate, 6.2 parts magnesium nitrate, and 2.9 parts aluminum nitrate were added to 30 parts water and stirred to dissolve, thus obtaining a salt solution; using the double-drop co-precipitation method, cyanuric acid aqueous solution (3.6 parts cyanuric acid and 50 parts water were stirred evenly at 70°C in a nitrogen atmosphere) and 2 mol / L sodium hydroxide aqueous solution were added dropwise, and the pH of the alkaline solution was controlled at 9.5. The solution was stirred for 8 hours; the solution was hydrothermally reacted at 170°C for 12 hours, washed and dried to obtain Ca-Mg-Al-LDH; (2) folic acid and Ca-Mg-Al-LDH with a mass ratio of 1.5:5 were dispersed in water, then mixed, ultrasonically dispersed for 30 minutes, centrifuged and dried to obtain folic acid modified Ca-Mg-Al-LDH;

[0030] Step 2: By weight, (1) add 20 parts red phosphorus and 4 parts melamine to 150 parts water, add 2.5 parts boric acid and 0.2 parts sodium hexametaphosphate, heat to 80℃ and stir for 5 hours, cool to 40℃ and continue stirring for 4 hours, vacuum filter and dry to obtain red phosphorus core; (2) add 5 parts β-cyclodextrin to 50 parts pyridine, stir at 75℃ for 2 hours to obtain β-cyclodextrin solution; add 24 parts red phosphorus core and 1 part surfactant Tween 80 to Stir 150 parts of pyridine evenly, add β-cyclodextrin solution dropwise at 75℃, stir for 1 hour, add toluene diisocyanate, continue stirring for 12 hours to form a shell; filter, wash, and dry to obtain red phosphorus microcapsules; (3) Disperse 10 parts of red phosphorus microcapsules in acetone, add alkaline solution to control pH to 8.2 under ice bath, slowly add 0.35 parts of stearoyl chloride and stir for 1 hour to adjust to neutral, wash and dry to obtain stearoyl chloride modified red phosphorus microcapsules;

[0031] Step 3: (1) Prepare polyvinyl chloride SG3, use dioctyl terephthalate and stearoyl chloride modified red phosphorus microcapsules in a mass ratio of 36:6 ​​as plasticizers, folic acid modified Ca-Mg-Al-LDH as stabilizers, 1250 mesh calcium carbonate, aluminum hydroxide, magnesium hydroxide, FA-500 polytetrafluoroethylene as anti-dripping agents, and barium stearate as synergist;

[0032] (2) By weight, 100 parts of polyvinyl chloride resin powder, 42 parts of plasticizer, 6 parts of stabilizer, 12 parts of calcium carbonate, 14 parts of aluminum hydroxide, 4 parts of magnesium hydroxide, 1 part of anti-drip agent and 0.5 parts of synergist are mixed in a high-speed mixer at 100°C and 800 r / min for 10 minutes, and then fed into a twin-screw extruder and extruded and granulated at 150°C and screw speed of 40 r / min to obtain polyvinyl chloride sheathed cable material.

[0033] Implementation Method 2: Step 1: By weight, (1) 0.63 parts calcium nitrate, 6.2 parts magnesium nitrate, and 2.9 parts aluminum nitrate were added to 30 parts water and stirred to dissolve, thus obtaining a salt solution; using the double-drop co-precipitation method, cyanuric acid aqueous solution (3.6 parts cyanuric acid and 50 parts water were stirred evenly at 70°C in a nitrogen atmosphere) and 2 mol / L sodium hydroxide aqueous solution were added dropwise, and the pH of the alkaline solution was controlled at 9.5. The solution was stirred for 8 hours; the solution was subjected to hydrothermal reaction at 170°C for 12 hours, washed and dried to obtain Ca-Mg-Al-LDH; (2) folic acid and Ca-Mg-Al-LDH with a mass ratio of 1.5:5 were dispersed in water, then mixed, ultrasonically dispersed for 30 minutes, centrifuged and dried to obtain folic acid modified Ca-Mg-Al-LDH;

[0034] Step 2: By weight, (1) add 20 parts red phosphorus and 4 parts melamine to 150 parts water, add 2.5 parts boric acid and 0.2 parts sodium hexametaphosphate, heat to 80℃ and stir for 5 hours, cool to 40℃ and continue stirring for 4 hours, vacuum filter and dry to obtain red phosphorus core; (2) add 5 parts β-cyclodextrin to 50 parts pyridine, stir at 75℃ for 2 hours to obtain β-cyclodextrin solution; add 24 parts red phosphorus core and 1 part surfactant Tween 80 to Stir 150 parts of pyridine evenly, add β-cyclodextrin solution dropwise at 75℃, stir for 1 hour, add toluene diisocyanate, continue stirring for 12 hours to form a shell; filter, wash, and dry to obtain red phosphorus microcapsules; (3) Disperse 10 parts of red phosphorus microcapsules in acetone, add alkaline solution to control pH to 8.2 under ice bath, slowly add 0.35 parts of stearoyl chloride and stir for 1 hour to adjust to neutral, wash and dry to obtain stearoyl chloride modified red phosphorus microcapsules;

[0035] Step 3: (1) Prepare polyvinyl chloride SG3, use dioctyl terephthalate and stearoyl chloride modified red phosphorus microcapsules in a mass ratio of 35:5 as plasticizers, folic acid modified Ca-Mg-Al-LDH as stabilizers, 1250 mesh calcium carbonate, aluminum hydroxide, magnesium hydroxide, FA-500 polytetrafluoroethylene as anti-dripping agents, and barium stearate as synergist;

[0036] (2) By weight, 100 parts of polyvinyl chloride resin powder, 40 parts of plasticizer, 7 parts of stabilizer, 15 parts of calcium carbonate, 10 parts of aluminum hydroxide, 2 parts of magnesium hydroxide, 2 parts of anti-drip agent and 1 part of synergist are mixed in a high-speed mixer at 100°C and 800 r / min for 10 minutes, and then fed into a twin-screw extruder and extruded and granulated at 150°C and screw speed of 40 r / min to obtain polyvinyl chloride sheathed cable material.

[0037] Implementation Method 3: Step 1: By weight, (1) 0.63 parts calcium nitrate, 6.2 parts magnesium nitrate, and 2.9 parts aluminum nitrate were added to 30 parts water and stirred to dissolve, thus obtaining a salt solution; using the double-drop co-precipitation method, cyanuric acid aqueous solution (3.6 parts cyanuric acid and 50 parts water were stirred evenly at 70°C in a nitrogen atmosphere) and 2 mol / L sodium hydroxide aqueous solution were added dropwise, and the pH of the alkaline solution was controlled at 9.5. The solution was stirred for 8 hours; the solution was subjected to hydrothermal reaction at 170°C for 12 hours, washed and dried to obtain Ca-Mg-Al-LDH; (2) folic acid and Ca-Mg-Al-LDH with a mass ratio of 1.5:5 were dispersed in water, then mixed, ultrasonically dispersed for 30 minutes, centrifuged and dried to obtain folic acid modified Ca-Mg-Al-LDH;

[0038] Step 2: By weight, (1) add 20 parts red phosphorus and 4 parts melamine to 150 parts water, add 2.5 parts boric acid and 0.2 parts sodium hexametaphosphate, heat to 80℃ and stir for 5 hours, cool to 40℃ and continue stirring for 4 hours, vacuum filter and dry to obtain red phosphorus core; (2) add 5 parts β-cyclodextrin to 50 parts pyridine, stir at 75℃ for 2 hours to obtain β-cyclodextrin solution; add 24 parts red phosphorus core and 1 part surfactant Tween 80 to Stir 150 parts of pyridine evenly, add β-cyclodextrin solution dropwise at 75℃, stir for 1 hour, add toluene diisocyanate, continue stirring for 12 hours to form a shell; filter, wash, and dry to obtain red phosphorus microcapsules; (3) Disperse 10 parts of red phosphorus microcapsules in acetone, add alkaline solution to control pH to 8.2 under ice bath, slowly add 0.35 parts of stearoyl chloride and stir for 1 hour to adjust to neutral, wash and dry to obtain stearoyl chloride modified red phosphorus microcapsules;

[0039] Step 3: (1) Prepare polyvinyl chloride SG3, use dioctyl terephthalate and stearoyl chloride modified red phosphorus microcapsules in a mass ratio of 38:7 as plasticizers, folic acid modified Ca-Mg-Al-LDH as stabilizers, 1250 mesh calcium carbonate, aluminum hydroxide, magnesium hydroxide, FA-500 polytetrafluoroethylene as anti-dripping agents, and barium stearate as synergist;

[0040] (2) By weight, 100 parts of polyvinyl chloride resin powder, 45 parts of plasticizer, 5 parts of stabilizer, 10 parts of calcium carbonate, 15 parts of aluminum hydroxide, 4 parts of magnesium hydroxide, 0.5 parts of anti-drip agent and 0.2 parts of synergist are mixed in a high-speed mixer at 100°C and 800 r / min for 10 minutes, and then fed into a twin-screw extruder and extruded and granulated at 150°C and screw speed of 40 r / min to obtain polyvinyl chloride sheathed cable material.

[0041] Comparative Example 1: The folic acid-modified Ca-Mg-Al-LDH was replaced with traditional Ca-Mg-Al-LDH, and the rest was the same as in Example 1; as follows:

[0042] Step 1: By weight, (1) add 0.63 parts calcium nitrate, 6.2 parts magnesium nitrate, and 2.9 parts aluminum nitrate to 30 parts water, stir to dissolve, and obtain a salt solution. Add 2 mol / L sodium hydroxide aqueous solution, control the pH of the alkaline solution to 9.5, and stir for 8 hours. Then, perform a hydrothermal reaction at 170℃ for 12 hours, wash and dry to obtain Ca-Mg-Al-LDH.

[0043] Step 2: By weight, (1) add 20 parts red phosphorus and 4 parts melamine to 150 parts water, add 2.5 parts boric acid and 0.2 parts sodium hexametaphosphate, heat to 80℃ and stir for 5 hours, cool to 40℃ and continue stirring for 4 hours, vacuum filter and dry to obtain red phosphorus core; (2) add 5 parts β-cyclodextrin to 50 parts pyridine, stir at 75℃ for 2 hours to obtain β-cyclodextrin solution; add 24 parts red phosphorus core and 1 part surfactant Tween 80 to Stir 150 parts of pyridine evenly, add β-cyclodextrin solution dropwise at 75℃, stir for 1 hour, add toluene diisocyanate, continue stirring for 12 hours to form a shell; filter, wash, and dry to obtain red phosphorus microcapsules; (3) Disperse 10 parts of red phosphorus microcapsules in acetone, add alkaline solution to control pH to 8.2 under ice bath, slowly add 0.35 parts of stearoyl chloride and stir for 1 hour to adjust to neutral, wash and dry to obtain stearoyl chloride modified red phosphorus microcapsules;

[0044] Step 3: (1) Prepare polyvinyl chloride SG3, and use dioctyl terephthalate and stearoyl chloride modified red phosphorus microcapsules in a mass ratio of 36:6 ​​as plasticizers, Ca-Mg-Al-LDH as stabilizers, 1250 mesh calcium carbonate, aluminum hydroxide, magnesium hydroxide, FA-500 polytetrafluoroethylene as anti-dripping agents, and barium stearate as synergist;

[0045] (2) By weight, 100 parts of polyvinyl chloride resin powder, 42 parts of plasticizer, 6 parts of stabilizer, 12 parts of calcium carbonate, 14 parts of aluminum hydroxide, 4 parts of magnesium hydroxide, 1 part of anti-drip agent and 0.5 parts of synergist are mixed in a high-speed mixer at 100°C and 800 r / min for 10 minutes, and then fed into a twin-screw extruder and extruded and granulated at 150°C and screw speed of 40 r / min to obtain polyvinyl chloride sheathed cable material.

[0046] Comparative Example 2: The plasticizer ratio is adjusted, but the rest is the same as in Implementation Method 1; the difference is:

[0047] Step 3: (1) Prepare polyvinyl chloride SG3, use dioctyl terephthalate and stearoyl chloride modified red phosphorus microcapsules with a plasticizer mass ratio of 30:12 as plasticizer, folic acid modified Ca-Mg-Al-LDH as stabilizer, 1250 mesh calcium carbonate, aluminum hydroxide, magnesium hydroxide, FA-500 polytetrafluoroethylene as anti-dripping agent, and barium stearate as synergist.

[0048] Comparative Example 3: The stearoyl chloride-modified red phosphorus microcapsules are replaced with red phosphorus microcapsules, and the rest is the same as in Example 1; the difference is:

[0049] Step 1: By weight, (1) 0.63 parts calcium nitrate, 6.2 parts magnesium nitrate, and 2.9 parts aluminum nitrate were added to 30 parts water and stirred to dissolve, thus obtaining a salt solution; using the double-drop co-precipitation method, cyanuric acid aqueous solution (3.6 parts cyanuric acid and 50 parts water were stirred evenly at 70°C in a nitrogen atmosphere) and 2 mol / L sodium hydroxide aqueous solution were added dropwise, and the pH of the alkaline solution was controlled at 9.5. The solution was stirred for 8 hours; the solution was hydrothermally reacted at 170°C for 12 hours, washed and dried to obtain Ca-Mg-Al-LDH; (2) folic acid and Ca-Mg-Al-LDH with a mass ratio of 1.5:5 were dispersed in water, then mixed, ultrasonically dispersed for 30 minutes, centrifuged and dried to obtain folic acid modified Ca-Mg-Al-LDH;

[0050] Step 2: By weight, (1) add 20 parts red phosphorus and 4 parts melamine to 150 parts water, add 2.5 parts boric acid and 0.2 parts sodium hexametaphosphate, heat to 80℃ and stir for 5 hours, cool to 40℃ and continue stirring for 4 hours, vacuum filter and dry to obtain red phosphorus core; (2) add 5 parts β-cyclodextrin to 50 parts pyridine, stir at 75℃ for 2 hours to obtain β-cyclodextrin solution; add 24 parts red phosphorus core and 1 part surfactant Tween 80 to 150 parts pyridine and stir evenly, add β-cyclodextrin solution dropwise at 75℃, stir for 1 hour, add toluene diisocyanate, continue stirring for 12 hours to form a shell; filter, wash and dry to obtain red phosphorus microcapsules;

[0051] Step 3: (1) Prepare polyvinyl chloride SG3, compound dioctyl terephthalate and red phosphorus microcapsules in a mass ratio of 36:6 ​​as plasticizer, folic acid modified Ca-Mg-Al-LDH as stabilizer, 1250 mesh calcium carbonate, aluminum hydroxide, magnesium hydroxide, FA-500 polytetrafluoroethylene as anti-drip agent, and barium stearate as synergist; (2) According to the weight parts, mix 100 parts of polyvinyl chloride resin powder, 42 parts of plasticizer, 6 parts of stabilizer, 12 parts of calcium carbonate, 14 parts of aluminum hydroxide, 4 parts of magnesium hydroxide, 1 part of anti-drip agent, and 0.5 parts of synergist in a high-speed mixer at 100℃ and 800r / min for 10 minutes, feed it into a twin-screw extruder, and extrude and granulate it at 150℃ and screw speed of 40r / min to obtain polyvinyl chloride sheathed cable material.

[0052] Comparative Example 4: In the raw materials for stearoyl chloride-modified red phosphorus microcapsules, the mass ratio of stearoyl chloride to red phosphorus microcapsules was adjusted to 10:0.8; the rest was the same as in Example 1; the difference was:

[0053] Step 2: By weight, (1) add 20 parts red phosphorus and 4 parts melamine to 150 parts water, add 2.5 parts boric acid and 0.2 parts sodium hexametaphosphate, heat to 80℃ and stir for 5 hours, cool to 40℃ and continue stirring for 4 hours, vacuum filter and dry to obtain red phosphorus core; (2) add 5 parts β-cyclodextrin to 50 parts pyridine, stir at 75℃ for 2 hours to obtain β-cyclodextrin solution; add 24 parts red phosphorus core and 1 part surfactant Tween 80 to Stir 150 parts of pyridine evenly, add β-cyclodextrin solution dropwise at 75℃, stir for 1 hour, add toluene diisocyanate, continue stirring for 12 hours to form a shell; filter, wash and dry to obtain red phosphorus microcapsules; (3) Disperse 10 parts of red phosphorus microcapsules in acetone, add alkaline solution to control pH to 8.2 under ice bath, slowly add 0.8 parts of stearoyl chloride and stir for 1 hour to adjust to neutral, wash and dry to obtain stearoyl chloride modified red phosphorus microcapsules.

[0054] Experimental testing: The PVC sheathed cable materials of Embodiments 1-3 and Comparative Examples 1-4 were pressed into samples at 170°C for 15 minutes. The tensile strength was tested at 250 mm / min according to GB / T8815-2008, and the oxygen index was tested according to GB / T2406.2-2009. The samples were aged at a constant temperature of 180°C for 7 days in a heat aging chamber, and then placed at room temperature for 24 hours. The tensile strength was tested again, and the tensile strength retention rate was calculated to define the heat aging resistance. The obtained data are shown in Table 1.

[0055] Table 1

[0056]

[0057] Results and Discussion: The above disclosure shows that the prepared PVC sheathed cable material has good strength, excellent flame retardancy, and heat aging resistance, which can meet the requirements for mining applications. Comparative Example 1, using unmodified Ca-Mg-Al-LDH, showed a significant performance decline due to insufficient compatibility and heat resistance; Comparative Example 2, with an unbalanced plasticizer ratio, led to deterioration of mechanical properties; Comparative Example 3, without stearoyl chloride modification, showed a significant decline in related properties; Comparative Example 4, with excessive stearoyl chloride, disrupted the molecular chain forces of PVC, resulting in impaired mechanical and flame retardant properties.

[0058] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lead- and arsenic-free polyvinyl chloride sheathed cable material, characterized in that: The raw materials of the polyvinyl chloride sheathed cable material include the following components by weight: 100 parts polyvinyl chloride resin powder, 40-45 parts plasticizer, 5-7 parts stabilizer, 10-15 parts calcium carbonate, 10-15 parts aluminum hydroxide, 2-4 parts magnesium hydroxide, 0.5-2 parts anti-drip agent, and 0.2-1 parts synergist. The stabilizer is folic acid-modified Ca-Mg-Al-LDH.

2. The lead- and arsenic-free polyvinyl chloride sheathed cable material according to claim 1, characterized in that: The preparation method of the folic acid-modified Ca-Mg-Al-LDH is as follows: (1) Add calcium nitrate, magnesium nitrate and aluminum nitrate to water and stir to dissolve to obtain a salt solution; use the double drop coprecipitation method to add cyanuric acid aqueous solution and alkaline solution dropwise at the same time, control the pH of the alkaline solution to 9~10, stir for 6~8 hours; hydrothermally react at 160~170℃ for 10~12 hours, wash and dry to obtain Ca-Mg-Al-LDH; (2) Disperse folic acid and Ca-Mg-Al-LDH separately in water, then mix them, ultrasonically disperse for 30-60 minutes, centrifuge and dry to obtain folic acid modified Ca-Mg-Al-LDH.

3. The lead- and arsenic-free polyvinyl chloride sheathed cable material according to claim 2, characterized in that: The raw materials for Ca-Mg-Al-LDH include the following components: 0.6-0.7 parts calcium nitrate, 6-7 parts magnesium nitrate, 2-3 parts aluminum nitrate, and 3-4 parts cyanuric acid; In the raw material for folic acid-modified Ca-Mg-Al-LDH, the mass ratio of folic acid to Ca-Mg-Al-LDH is 1~2:

5.

4. The lead- and arsenic-free polyvinyl chloride sheathed cable material according to claim 1, characterized in that: The plasticizer is composed of dioctyl terephthalate and stearoyl chloride-modified red phosphorus microcapsules in a mass ratio of 35~38:5~7.

5. The lead- and arsenic-free polyvinyl chloride sheathed cable material according to claim 4, characterized in that: The preparation method of the stearoyl chloride modified red phosphorus microcapsules includes the following steps: (1) Add red phosphorus and melamine to water, add boric acid and sodium hexametaphosphate, heat to 75~80℃ and stir for 4~5h, cool to 40~45℃ and continue stirring for 3~4h, vacuum filter and dry to obtain red phosphorus core; (2) Add β-cyclodextrin to pyridine and stir at 70-80℃ for 1-2 hours to obtain β-cyclodextrin solution; add red phosphorus core and surfactant to pyridine and stir evenly; add β-cyclodextrin solution dropwise at 70-80℃ and stir for 1-2 hours; add diisocyanate and continue stirring for 10-12 hours to form a shell; filter, wash and dry to obtain red phosphorus microcapsules; (3) Disperse the red phosphorus microcapsules in acetone, add alkaline solution under ice bath to control the pH to 8~8.5, slowly add stearoyl chloride and stir for 0.5~1 hour to adjust to neutral, wash and dry to obtain stearoyl chloride modified red phosphorus microcapsules.

6. The lead- and arsenic-free polyvinyl chloride sheathed cable material according to claim 5, characterized in that: The raw materials for the red phosphorus core include the following components: by weight, 18-25 parts red phosphorus, 3-4 parts melamine, 1-3 parts boric acid, 0.1-0.3 parts sodium hexametaphosphate, and 150-180 parts water; The raw materials for the red phosphorus microcapsules include the following components: by weight, 5-6 parts β-cyclodextrin, 20-25 parts red phosphorus core, and 6-8 parts diisocyanate; The raw materials for the stearoyl chloride-modified red phosphorus microcapsules include red phosphorus microcapsules and stearoyl chloride in a mass ratio of 10:0.2~0.

4.

7. The lead- and arsenic-free polyvinyl chloride sheathed cable material according to claim 1, characterized in that: The polyvinyl chloride powder is one or both of SG3 and SG5; the anti-drip agent is polytetrafluoroethylene; and the synergist is barium stearate.

8. The method for preparing a lead- and arsenic-free polyvinyl chloride sheathed cable material according to claim 1, characterized in that: Polyvinyl chloride resin powder, plasticizer, stabilizer, calcium carbonate, aluminum hydroxide, magnesium hydroxide, anti-drip agent, and synergist are mixed evenly and then extruded and granulated at 130~160℃ to obtain polyvinyl chloride sheathed cable material.

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