Weather-resistant flame-retardant cable material and preparation method thereof
By using modified ammonium polyphosphate and composite plasticizers, combined with modified kaolin, the problems of decreased mechanical properties and low flame retardant efficiency of cable materials during long-term outdoor use have been solved, resulting in cable materials with high weather resistance and flame retardancy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU DENGFENG NEW MATERIAL TECHNOLOGY CO LTD
- Filing Date
- 2026-03-16
- Publication Date
- 2026-06-09
AI Technical Summary
Existing cable materials are prone to mechanical property degradation due to photo-oxidative aging and thermo-oxidative degradation during long-term outdoor use. They also have low flame retardant efficiency and insufficient weather resistance, making it difficult to balance long-term stability and processing performance.
Modified ammonium polyphosphate is used as a flame retardant. Aromatic benzene ring structure and phosphazene structure are introduced through the combination of composite plasticizer and filler additives to enhance the rigidity and compatibility of the molecular chain. Furthermore, the interfacial bonding force is improved by modifying kaolin.
It significantly improves the weather resistance, flame retardancy, and mechanical properties of cable materials, extends their service life, reduces moisture absorption and conductivity, and enhances compatibility and interfacial bonding.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of cable material processing technology, specifically to a weather-resistant flame-retardant cable material and its preparation method. Background Technology
[0002] In recent years, with the rapid development of power transmission, rail transit and new energy fields, higher requirements have been placed on the weather resistance and flame retardant properties of cable materials. Weather-resistant flame-retardant cable materials, as a type of polymer composite material that combines UV resistance, high and low temperature resistance, damp heat aging resistance and flame retardant properties, have become a research hotspot in the industry.
[0003] Traditional cable materials often use halogenated flame retardants or inorganic fillers for modification. While these can achieve short-term flame retardant effects, they are prone to mechanical property degradation and even flame retardant failure during long-term outdoor use due to problems such as photo-oxidative aging and thermo-oxidative degradation. In addition, existing methods for improving weather resistance through blending modification or surface coating often fail to balance long-term stability and processing performance due to poor compatibility or insufficient interfacial bonding. For example, some halogen-free flame retardant systems are environmentally friendly but lack weather resistance and are prone to molecular chain breakage in humid, hot, or strong ultraviolet environments. Furthermore, some weather-resistant modifiers may interfere with the flame retardant synergy, leading to a decrease in the limiting oxygen index.
[0004] Currently, the performance defects of weather-resistant flame-retardant cable materials mainly stem from the limitations of molecular structure design and component interactions. In terms of weather resistance, if the polymer matrix lacks a stable conjugated structure or steric hindrance protection groups in its molecular chain, ultraviolet irradiation will trigger a free radical chain reaction, leading to main chain breakage or excessive cross-linking, which manifests as material embrittlement or surface powdering. In addition, insufficient compatibility between the flame retardant and the matrix will lead to micro-phase separation, which accelerates the penetration of water molecules at the interface in a humid and hot environment, hydrolyzes sensitive bonds, and further reduces the stability of the material.
[0005] Therefore, developing a cable material that combines long-lasting weather resistance, high flame retardancy efficiency, and good processing performance remains a technological bottleneck that the industry urgently needs to overcome. Based on existing technologies, the industry is turning to composite modified materials to solve problems such as poor weather resistance, low flame retardancy efficiency, and poor mechanical properties of cable materials. Summary of the Invention
[0006] The purpose of this invention is to provide a weather-resistant flame-retardant cable material and its preparation method, which solves the technical problem that the weather resistance, flame retardant efficiency and mechanical properties of existing cable materials need to be further improved.
[0007] The objective of this invention can be achieved through the following technical solution: a weather-resistant flame-retardant cable material, wherein the weather-resistant flame-retardant cable material comprises the following components by weight: 50-80 parts of polyvinyl chloride, 12-16 parts of modified ammonium polyphosphate, 30-60 parts of composite plasticizer, and 25-35 parts of filler additive.
[0008] The filler additive is composed of dioctyl adipate, modified kaolin, and nitrile rubber powder in a weight ratio of 5:2:3.
[0009] The modified ammonium polyphosphate is prepared by adding 4,4-diaminodiphenyl ether and pyridine into a four-necked flask, stirring in an ice bath for 10-20 min, adding ammonium polyphosphate into the system, stirring for 1-2 h, adding hexachlorocyclotriphosphazene dropwise, raising the temperature to 70-90℃, reacting for 20-25 h, and then performing post-treatment to obtain modified ammonium polyphosphate.
[0010] The synthesis mechanism of modified ammonium polyphosphate is as follows:
[0011]
[0012]
[0013] In the formula: R1: R2: R3: An asterisk (*) indicates a connection site for R.
[0014] Pyridine, as an acid-binding agent, can form a weak coordination structure with the amino group of 4,4-diaminodiphenyl ether, enhancing the nucleophilicity of the amino group. After the addition of ammonium polyphosphate, some hydroxyl groups first undergo nucleophilic substitution with the chlorine atom of hexachlorocyclotriphosphazene. The amino group of 4,4-diaminodiphenyl ether attacks the phosphorus atom of hexachlorocyclotriphosphazene to replace the chlorine atom, forming a phosphorus-nitrogen bond. At the same time, hydrochloric acid is removed, generating a linear or cyclic intermediate. The remaining chlorine atoms of the intermediate continue to form a cross-linking network with the hydroxyl or ammonium groups on the surface of ammonium polyphosphate, gradually building a coating layer on the surface of ammonium polyphosphate to obtain modified ammonium polyphosphate.
[0015] Furthermore, the ratio of 4,4-diaminodiphenyl ether, pyridine, ammonium polyphosphate, and hexachlorocyclotriphosphazene is 4g:40mL:3g:1g; the post-treatment step is as follows: after the reaction is completed, the reaction product is cooled to room temperature, filtered, washed three times with anhydrous ethanol and deionized water, and dried in a vacuum drying oven at 60-80℃ until constant weight to obtain modified ammonium polyphosphate.
[0016] Furthermore, the preparation method of the composite plasticizer is as follows:
[0017] A1. Castor oil, glacial acetic acid and phosphoric acid are added to a four-necked flask equipped with a constant pressure dropping funnel and stirred. Hydrogen peroxide is added dropwise, the temperature is raised to 50-60℃, and the reaction is carried out for 4-5 hours. After post-treatment, epoxidized castor oil is obtained.
[0018] A2. Add epoxidized castor oil and toluene to a three-necked flask and stir. Then add a mixed solution of diethyl phosphate, raise the temperature to 70-80℃, react for 4-5 hours, and then perform post-treatment to obtain a composite plasticizer.
[0019] The synthesis reaction mechanism of composite plasticizers is as follows:
[0020]
[0021]
[0022] In the formula: R: An asterisk (*) indicates a connection site for R.
[0023] Glacial acetic acid and phosphoric acid provide an acidic environment, promoting the decomposition of hydrogen peroxide and its reaction with acetic acid to produce peracetic acid. Peracetic acid acts as an epoxidizing agent, with the oxygen atom of the peroxide bond attacking the π bond of the castor oil double bond to form a three-membered epoxy ring. The OO bond of peracetic acid breaks, releasing acetic acid and generating epoxidized castor oil. The epoxy group of epoxidized castor oil has high reactivity. Under acidic conditions, the phosphoryl group of diethyl phosphate acts as an electrophile to attack a carbon atom of the epoxy ring, causing the ring to open and forming a new structure containing phosphate ester, thus obtaining a composite plasticizer.
[0024] Further, in step A1, the weight ratio of castor oil, glacial acetic acid, phosphoric acid, and hydrogen peroxide is 10:1.5:1:8; the post-treatment step is as follows: after the reaction, wash with deionized water until neutral, and distill under reduced pressure at 60-80℃ to obtain epoxidized castor oil; in step A2, the weight ratio of the mixed solution of epoxidized castor oil, toluene, and diethyl phosphate is 1:0.8:0.11, and the mixed solution of diethyl phosphate is composed of toluene, phosphoric acid, and triphenylphosphine in a dosage ratio of 90mL30g:0.1g; the post-treatment step is as follows: after the reaction, adjust the pH to neutral with saturated sodium hydroxide solution, and then distill under reduced pressure at 60-80℃ to obtain the composite plasticizer.
[0025] Furthermore, the preparation method of the modified kaolin is as follows: pretreated kaolin and KH-570 solution are added to a stirrer and stirred for 15-30 minutes, the temperature is raised to 60-80℃, the reaction is carried out for 1-2 hours, the temperature is further raised to 80-100℃, the reaction is carried out for 2-3 hours, and then post-treatment is performed to obtain modified kaolin.
[0026] Furthermore, the ratio of the pretreated kaolin to the silane coupling agent solution is 1g:5-10mL; the KH-570 solution is composed of γ-methacryloxypropyltrimethoxysilane, ethanol, and purified water at a ratio of 3g:90mL:10mL; the post-treatment steps are as follows: after the reaction is completed, the reaction material is filtered, the filter cake is washed 2-3 times with anhydrous ethanol, and then transferred to a vacuum drying oven at 80-100℃ to dry to constant weight to obtain modified kaolin.
[0027] Furthermore, the pre-treated kaolin is processed as follows: Kaolin is crushed in a crusher to a particle size of less than 200 mesh. The crushed kaolin and calcium carbonate are added to a rotary kiln under a nitrogen atmosphere at a ratio of 1:1. The temperature of the rotary kiln is set to 1000-1200℃ and calcined for 3-5 hours. After cooling to room temperature, it is filtered through a 200-mesh sieve to obtain pre-treated kaolin.
[0028] This invention also proposes a method for preparing weather-resistant flame-retardant cable material, comprising the following steps:
[0029] S1. Add polyvinyl chloride, modified ammonium polyphosphate, composite plasticizer, and filler additives to a mixer and mix evenly to obtain a mixture;
[0030] S2. Add the mixture to a twin-screw extruder and melt-extrude to obtain weather-resistant flame-retardant cable material.
[0031] The present invention has the following beneficial effects:
[0032] 1. This invention improves the thermal shock resistance, impact embrittlement resistance, and mechanical properties of cable materials by using modified ammonium polyphosphate as a flame retardant, compounding and plasticizing castor oil, and adding filler additives. The introduction of aromatic benzene rings into modified ammonium polyphosphate enhances the rigidity of the molecular chain through conjugation, increasing the decomposition temperature. The benzene ring of 4,4-diaminodiphenyl ether readily undergoes aromatization at high temperatures, promoting the formation of a carbon layer to isolate oxygen and heat. The introduction of phosphazene structures increases the phosphorus content, and phosphorus tends to remain in a stable glassy or ceramic state, enhancing the flame retardant effect of the condensed phase. Synergistically with the ammonium ions of ammonium polyphosphate, it can form a more efficient intumescent flame retardant system with gas and carbon sources, improving the flame retardant performance of cable materials. Furthermore, after modification, some ammonium ions are replaced by phosphorus-nitrogen bonds in the phosphazene structure, reducing hygroscopicity. The hydrophobicity of the benzene ring and the rigid structure of the phosphazene ring improve compatibility with polymer substrates and reduce flame retardant migration and precipitation. By introducing aromatic structures and phosphazene crosslinking networks, the ion migration capacity and carrier concentration of ammonium polyphosphate are significantly reduced, while the enhancing effect of hygroscopicity on conductivity is weakened, increasing the volume resistivity.
[0033] 2. This invention improves the weather resistance, oxidation resistance, and mechanical properties of cable materials by modifying the plasticizer. Long-chain fatty acid groups in the plasticizer insert between the polyvinyl chloride (PVC) molecular chains, expanding the tightly packed chains and reducing the entanglement force and interaction energy between chain segments. This makes PVC more prone to chain segment movement at room temperature, resulting in greater flexibility and ductility, and improving the material's elongation at break. By reacting with diethyl phosphate to introduce phosphate groups, the molecular polarity and interaction with the polymer of the composite plasticizer are enhanced, improving plasticizing efficiency. Simultaneously, the steric hindrance effect of the phosphate groups slows down plasticizer migration, extending the service life of the cable material. The phosphate groups also possess excellent hydrolysis resistance and oxidation resistance, protecting the main chain from moisture and oxygen. Gas erosion significantly improves the stability of composite plasticizers in humid or high-temperature environments; the epoxy groups in epoxy castor oil can undergo weak chemical reactions with a small amount of active hydrogen or unstable chlorine atoms in polyvinyl chloride molecules to form partial covalent bonds or hydrogen bonds, enhancing the compatibility of plasticizers with polyvinyl chloride and reducing plasticizer migration and exudation; the epoxy groups in epoxy castor oil can preferentially decompose in ultraviolet or oxidative environments, capturing free radicals generated by the photo-oxidation of polyvinyl chloride and preventing free radical chain reactions; at the same time, triphenylphosphine in the diethyl phosphate mixed solution is a highly efficient antioxidant that can scavenge peroxide free radicals and inhibit oxidative degradation.
[0034] 3. Pretreated kaolin possesses a high specific surface area and porous structure, providing more active sites for bonding with polyvinyl chloride (PVC). Modified kaolin is uniformly dispersed in the PVC melt, enhancing interfacial bonding through physical filling and chemical bonding, significantly improving the tensile strength and tear resistance of the material, balancing flexibility and rigidity. The organic long chains of KH-570 reduce the surface energy of kaolin, making it easier to disperse in the PVC melt, avoiding defects caused by filler aggregation, improving melt compatibility, and reducing viscosity during basic processing. After calcination, kaolin is resistant to high temperatures, and the enhanced interfacial bonding after modification further delays the thermal decomposition of PVC. The lamellar structure of kaolin can hinder charge migration and increase volume resistivity. Synergistically with flame retardants, it delays flame spread through a physical barrier effect, further improving flame retardant performance. Detailed Implementation
[0035] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.
[0036] In this application, the polyvinyl chloride is from Shanghai Aixuan Engineering Plastics, CAS number 9002-86-2, and the softening temperature is 85℃; KH-570 is γ-methacryloyloxypropyltrimethoxysilane, from Hangzhou Jessica Chemical Co., Ltd., CAS number 2530-85-0.
[0037] Example 1
[0038] This embodiment provides a weather-resistant flame-retardant cable material and its preparation method, including the following steps:
[0039] S1. Preparation of modified ammonium polyphosphate
[0040] Weigh 35g of 4,4-diaminodiphenyl ether and 400mL of pyridine into a four-necked flask, stir for 10min in an ice bath, add 30g of ammonium polyphosphate to the system, stir for 1h, add 10g of hexachlorocyclotriphosphazene dropwise, raise the temperature to 70℃, and react for 20h. After the reaction is complete, cool the product to room temperature, filter, wash the product three times with anhydrous ethanol and deionized water, and dry it in a vacuum drying oven at 60℃ to constant weight to obtain modified ammonium polyphosphate.
[0041] S2, Preparation of composite plasticizers
[0042] Mix 90 mL of toluene, 30 g of phosphoric acid, and 0.1 g of triphenylphosphine to obtain a diethyl phosphate solution for later use.
[0043] Weigh out: Add 100g castor oil, 15g glacial acetic acid and 1g phosphoric acid to a four-necked flask equipped with a constant pressure dropping funnel and stir. Add 50g hydrogen peroxide dropwise, raise the temperature to 50℃, react for 4h, wash with deionized water until neutral, and distill under reduced pressure at 60℃ to obtain epoxidized castor oil.
[0044] Weigh out 100g of epoxidized castor oil and 80g of toluene and add them to a three-necked flask. Stir and then add 110g of diethyl phosphate mixed solution. Raise the temperature to 70℃ and react for 4 hours. After the reaction is complete, adjust the pH to neutral with saturated sodium hydroxide solution and then distill under reduced pressure at 60℃ to obtain the composite plasticizer.
[0045] S3, Preparation of modified kaolin
[0046] Mix 30g of γ-methacryloxypropyltrimethoxysilane, 900mL of ethanol and 100mL of purified water to obtain KH-570 solution for later use;
[0047] Weigh 100g of kaolin and put it into a crusher to crush it to a particle size of less than 200 mesh. Add the crushed kaolin and 100g of calcium carbonate into a rotary kiln under a nitrogen atmosphere. Set the temperature of the rotary kiln to 1000℃ and calcine for 3 hours. After cooling to room temperature, filter it through a 200-mesh sieve to obtain pretreated kaolin.
[0048] Weigh 100g of pretreated kaolin and 500mL of KH-570 solution and add them to a stirrer. Stir for 15min, raise the temperature to 60℃ and react for 1h. Continue to raise the temperature to 80℃ and react for 2h. After the reaction is complete, filter the reaction material, wash the filter cake twice with anhydrous ethanol, and then transfer it to a vacuum drying oven at 80-1℃ to dry to constant weight to obtain modified kaolin.
[0049] S4. Preparation of weather-resistant and flame-retardant cable material
[0050] Weigh out 50 parts of polyvinyl chloride, 12 parts of modified ammonium polyphosphate, 30 parts of composite plasticizer, 12.5 parts of dioctyl adipate, 5 parts of modified kaolin and 7.5 parts of nitrile rubber powder and add them to a mixer and mix evenly to obtain a mixture.
[0051] The mixture is added to a twin-screw extruder, and the temperature and pressure of each zone are set as follows: feeding zone temperature 60℃, pressure 2MPa; compression zone temperature 120℃, pressure 8MPa; metering zone temperature 160℃, pressure 10MPa; die head temperature 170℃, pressure 5MPa; die temperature 180℃, pressure 2MPa; and screw speed 300-400rpm. The mixture is melt-extruded to obtain weather-resistant flame-retardant cable material.
[0052] Example 2
[0053] This embodiment provides a weather-resistant flame-retardant cable material and its preparation method, including the following steps:
[0054] S1. Preparation of modified ammonium polyphosphate
[0055] Weigh 35g of 4,4-diaminodiphenyl ether and 400mL of pyridine into a four-necked flask, stir for 15min in an ice bath, add 30g of ammonium polyphosphate to the system, stir for 1h, add 10g of hexachlorocyclotriphosphazene dropwise, raise the temperature to 80℃, and react for 23h. After the reaction is complete, cool the product to room temperature, filter, wash the product three times with anhydrous ethanol and deionized water, and dry it in a vacuum drying oven at 70℃ to constant weight to obtain modified ammonium polyphosphate.
[0056] S2, Preparation of composite plasticizers
[0057] Mix 90 mL of toluene, 30 g of phosphoric acid, and 0.1 g of triphenylphosphine to obtain a diethyl phosphate solution for later use.
[0058] Weigh out: 100g castor oil, 15g glacial acetic acid and 1g phosphoric acid into a four-necked flask equipped with a constant pressure dropping funnel and stir. Add 50g hydrogen peroxide dropwise, raise the temperature to 60℃, react for 4.5h, wash with deionized water until neutral, and distill under reduced pressure at 70℃ to obtain epoxidized castor oil.
[0059] Weigh out 100g of epoxidized castor oil and 80g of toluene and add them to a three-necked flask. Stir, then add 110g of diethyl phosphate mixed solution. Raise the temperature to 75℃ and react for 4.5h. After the reaction is complete, adjust the pH to neutral with saturated sodium hydroxide solution, and then distill under reduced pressure at 70℃ to obtain the composite plasticizer.
[0060] S3, Preparation of modified kaolin
[0061] Mix 30g of γ-methacryloxypropyltrimethoxysilane, 900mL of ethanol and 100mL of purified water to obtain KH-570 solution for later use;
[0062] Weigh 100g of kaolin and put it into a crusher to crush it to a particle size of less than 200 mesh. Add the crushed kaolin and 100g of calcium carbonate into a rotary kiln under a nitrogen atmosphere. Set the temperature of the rotary kiln to 1100℃ and calcine for 4 hours. After cooling to room temperature, filter it through a 200-mesh sieve to obtain pretreated kaolin.
[0063] Weigh 100g of pretreated kaolin and 500mL of KH-570 solution and add them to a stirrer. Stir for 20min, raise the temperature to 70℃ and react for 1.5h. Continue to raise the temperature to 90℃ and react for 2-3h. After the reaction is complete, filter the reaction material, wash the filter cake three times with anhydrous ethanol, and then transfer it to a 90℃ vacuum drying oven to dry to constant weight to obtain modified kaolin.
[0064] S4. Preparation of weather-resistant and flame-retardant cable material
[0065] Weigh out 50 parts of polyvinyl chloride, 12 parts of modified ammonium polyphosphate, 30 parts of composite plasticizer, 12.5 parts of dioctyl adipate, 5 parts of modified kaolin and 7.5 parts of nitrile rubber powder and add them to a mixer and mix evenly to obtain a mixture.
[0066] The mixture is added to a twin-screw extruder, and the temperature and pressure of each zone are set as follows: feeding zone temperature 70℃, pressure 3MPa; compression zone temperature 150℃, pressure 10MPa; metering zone temperature 175℃, pressure 15MPa; die head temperature 180℃, pressure 10MPa; die temperature 190℃, pressure 6MPa; and screw speed 350rpm. The mixture is melt-extruded to obtain weather-resistant flame-retardant cable material.
[0067] Example 3
[0068] This embodiment provides a weather-resistant flame-retardant cable material and its preparation method, including the following steps:
[0069] S1. Preparation of modified ammonium polyphosphate
[0070] Weigh 35g of 4,4-diaminodiphenyl ether and 400mL of pyridine into a four-necked flask, stir for 20min in an ice bath, add 30g of ammonium polyphosphate to the system, stir for 2h, add 10g of hexachlorocyclotriphosphazene dropwise, raise the temperature to 90℃, and react for 25h. After the reaction is complete, cool the product to room temperature, filter, wash the product three times with anhydrous ethanol and deionized water, and dry it in an 80℃ vacuum drying oven to constant weight to obtain modified ammonium polyphosphate.
[0071] S2, Preparation of composite plasticizers
[0072] Mix 90 mL of toluene, 30 g of phosphoric acid, and 0.1 g of triphenylphosphine to obtain a diethyl phosphate solution for later use.
[0073] Weigh out: Add 100g castor oil, 15g glacial acetic acid and 1g phosphoric acid to a four-necked flask equipped with a constant pressure dropping funnel and stir. Add 50g hydrogen peroxide dropwise, raise the temperature to 60℃, react for 5h, wash with deionized water until neutral, and distill under reduced pressure at 80℃ to obtain epoxidized castor oil.
[0074] Weigh out 100g of epoxidized castor oil and 80g of toluene and add them to a three-necked flask. Stir and then add 110g of diethyl phosphate mixed solution. Raise the temperature to 80℃ and react for 5 hours. After the reaction is complete, adjust the pH to neutral with saturated sodium hydroxide solution and then distill under reduced pressure at 80℃ to obtain the composite plasticizer.
[0075] S3, Preparation of modified kaolin
[0076] Mix 30g of γ-methacryloxypropyltrimethoxysilane, 900mL of ethanol and 100mL of purified water to obtain KH-570 solution for later use;
[0077] Weigh 100g of kaolin and put it into a crusher to crush it to a particle size of less than 200 mesh. Add the crushed kaolin and 100g of calcium carbonate into a rotary kiln under a nitrogen atmosphere. Set the temperature of the rotary kiln to 1200℃ and calcine for 5 hours. After cooling to room temperature, filter it through a 200-mesh sieve to obtain pretreated kaolin.
[0078] Weigh 100g of pretreated kaolin and 500mL of KH-570 solution and add them to a stirrer. Stir for 30min, raise the temperature to 80℃ and react for 2h. Continue to raise the temperature to 100℃ and react for 3h. After the reaction is complete, filter the reaction material, wash the filter cake three times with anhydrous ethanol, and then transfer it to a vacuum drying oven at 100℃ to dry to constant weight to obtain modified kaolin.
[0079] S4. Preparation of weather-resistant and flame-retardant cable material
[0080] Weigh out 50 parts of polyvinyl chloride, 12 parts of modified ammonium polyphosphate, 30 parts of composite plasticizer, 12.5 parts of dioctyl adipate, 5 parts of modified kaolin and 7.5 parts of nitrile rubber powder and add them to a mixer and mix evenly to obtain a mixture.
[0081] The mixture is added to a twin-screw extruder, and the temperature and pressure of each zone are set as follows: feeding zone temperature 60-80℃, pressure 5MPa; compression zone temperature 160℃, pressure 15MPa; metering zone temperature 190℃, pressure 20MPa; die head temperature 190℃, pressure 15MPa; die temperature 200℃, pressure 8MPa; and screw speed 400rpm. The mixture is melt-extruded to obtain weather-resistant flame-retardant cable material.
[0082] Comparative Example 1
[0083] The difference between this comparative example and Example 3 is that step S1 is omitted, and the modified ammonium polyphosphate is replaced with ammonium polyphosphate in step S1.
[0084] Comparative Example 2
[0085] The difference between this comparative example and Example 3 is that diethyl phosphate mixed solution is not added in step S2.
[0086] Comparative Example 3
[0087] The difference between this comparative example and Example 3 is that step S3 is omitted, and the castor oil in step S3 is used instead of the composite plasticizer.
[0088] Comparative Example 4
[0089] The difference between this comparative example and Example 3 is that step S4 is omitted, and the kaolin in step S4 is replaced with modified kaolin.
[0090] Performance testing:
[0091] The volume resistivity, thermal shock resistance, and impact embrittlement properties of the weather-resistant flame-retardant cable materials prepared in Examples 1-3 and Comparative Examples 1-4 were determined according to the standard GB / T 32129-2015 "Halogen-free Low-smoke Flame-retardant Cable Materials for Wires and Cables". The thermal shock resistance test temperature was 130±3℃ and the test time was 1h; the impact embrittlement temperature was -25℃ and the number of broken test specimens was tested.
[0092] The tensile strength and elongation at break of the weather-resistant flame-retardant cable materials prepared in Examples 1-3 and Comparative Examples 1-4 were determined according to standard GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets". The specific test results are shown in Table 1 below:
[0093] Table 1 - Performance Test Data of Samples
[0094]
[0095] Data Analysis:
[0096] Comparative analysis of the data in Table 1 above shows that the weather-resistant flame-retardant cable material prepared by this invention has a tensile strength of 39 MPa, an elongation at break of 455%, and a volume resistivity of 1*10⁻⁶. 16 The thermal shock resistance was uncracking, and the number of fractures in the impact embrittlement performance was 0. This indicates that the present invention improves the thermal shock resistance, impact embrittlement performance, and mechanical properties of cable materials by using modified ammonium polyphosphate as a flame retardant, compounding and plasticizing castor oil, and adding filler additives.
[0097] Compared with the examples, the modified ammonium polyphosphate introduced aromatic benzene ring structure and phosphazene structure, which enhanced the rigidity of the molecular chain and improved the flame retardant performance and volume resistivity of the cable material.
[0098] Compared with the examples, the triphenylphosphine in the diethyl phosphate mixed solution in Comparative Example 2 is a highly efficient antioxidant that can scavenge peroxide free radicals and inhibit oxidative degradation.
[0099] Compared with the examples, Comparative Example 3 introduces phosphate groups through reaction with diethyl phosphate, which enhances the molecular polarity of the composite plasticizer and its interaction with the polymer, thereby improving plasticizing efficiency. At the same time, the steric hindrance effect of the phosphate groups can slow down the migration of the plasticizer and extend the service life of the cable material. The phosphate groups also have excellent hydrolysis resistance and antioxidant properties.
[0100] Compared with the examples, in Comparative Example 4, the modified kaolin is uniformly dispersed in the polyvinyl chloride matrix. Through physical filling and chemical bonding, the interfacial bonding force is enhanced, which significantly improves the tensile strength and tear resistance of the material, balances flexibility and rigidity, and the modified kaolin further delays the thermal decomposition of polyvinyl chloride. The lamellar structure of kaolin can hinder charge migration and increase volume resistivity. In synergy with flame retardants, it delays flame spread through physical barrier effect, further improving flame retardant performance.
[0101] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A weather-resistant flame-retardant cable material, characterized in that, The weather-resistant flame-retardant cable material comprises the following components by weight: 50-80 parts of polyvinyl chloride, 12-16 parts of modified ammonium polyphosphate, 30-60 parts of composite plasticizer, and 25-35 parts of filler additives. The filler additive is composed of dioctyl adipate, modified kaolin, and nitrile rubber powder in a weight ratio of 5:2:
3. The modified ammonium polyphosphate is prepared by adding 4,4-diaminodiphenyl ether and pyridine into a four-necked flask, stirring in an ice bath for 10-20 min, adding ammonium polyphosphate into the system, stirring for 1-2 h, adding hexachlorocyclotriphosphazene dropwise, raising the temperature to 70-90℃, reacting for 20-25 h, and then performing post-treatment to obtain modified ammonium polyphosphate.
2. The weather-resistant flame-retardant cable material according to claim 1, characterized in that, The ratio of 4,4-diaminodiphenyl ether, pyridine, ammonium polyphosphate, and hexachlorocyclotriphosphazene is 3.5g:40mL:3g:1g. The post-treatment steps are as follows: after the reaction is completed, the reaction product is cooled to room temperature, filtered, washed three times with anhydrous ethanol and deionized water, and dried in a vacuum drying oven at 60-80℃ to constant weight to obtain modified ammonium polyphosphate.
3. The weather-resistant flame-retardant cable material according to claim 1, characterized in that, The preparation method of the composite plasticizer is as follows: A1. Castor oil, glacial acetic acid and phosphoric acid are added to a four-necked flask equipped with a constant pressure dropping funnel and stirred. Hydrogen peroxide is added dropwise, the temperature is raised to 50-60℃, and the reaction is carried out for 4-5 hours. After post-treatment, epoxidized castor oil is obtained. A2. Add epoxidized castor oil and toluene to a three-necked flask and stir. Then add a mixed solution of diethyl phosphate, raise the temperature to 70-80℃, react for 4-5 hours, and then perform post-treatment to obtain a composite plasticizer.
4. The weather-resistant flame-retardant cable material according to claim 3, characterized in that, In step A1, the weight ratio of castor oil, glacial acetic acid, phosphoric acid, and hydrogen peroxide is 10:1.5:1:
8. The post-treatment step is as follows: after the reaction, wash with deionized water until neutral, and distill under reduced pressure at 60-80℃ to obtain epoxidized castor oil. In step A2, the weight ratio of the mixed solution of epoxidized castor oil, toluene, and diethyl phosphate is 1:0.8:0.
11. The mixed solution of diethyl phosphate is composed of toluene, phosphoric acid, and triphenylphosphine in a dosage ratio of 90mL30g:0.1g. The post-treatment step is as follows: after the reaction, adjust the pH to neutral with saturated sodium hydroxide solution, and then distill under reduced pressure at 60-80℃ to obtain the composite plasticizer.
5. The weather-resistant flame-retardant cable material according to claim 1, characterized in that, The modified kaolin is prepared by adding pretreated kaolin and KH-570 solution into a stirrer and stirring for 15-30 minutes. The temperature is raised to 60-80℃ and reacted for 1-2 hours. The temperature is then raised to 80-100℃ and reacted for 2-3 hours. After post-treatment, the modified kaolin is obtained.
6. The weather-resistant flame-retardant cable material according to claim 5, characterized in that, The ratio of the pretreated kaolin to the silane coupling agent solution is 1g:5-10mL; the KH-570 solution is composed of γ-methacryloxypropyltrimethoxysilane, ethanol and purified water in a ratio of 3g:90mL:10mL; the post-treatment steps are as follows: after the reaction is completed, the reaction material is filtered, the filter cake is washed 2-3 times with anhydrous ethanol, and then transferred to a vacuum drying oven at 80-100℃ to dry to constant weight to obtain modified kaolin.
7. The weather-resistant flame-retardant cable material according to claim 5, characterized in that, The pretreatment method for kaolin is as follows: Kaolin is crushed in a crusher to a particle size of less than 200 mesh. The crushed kaolin and calcium carbonate are added to a rotary kiln under nitrogen atmosphere at a weight ratio of 1:
1. The temperature of the rotary kiln is set to 1000-1200℃ and calcined for 3-5 hours. After cooling to room temperature, it is filtered through a 200-mesh sieve to obtain pretreated kaolin.
8. A method for preparing a weather-resistant flame-retardant cable material according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Add polyvinyl chloride, modified ammonium polyphosphate, composite plasticizer, and filler additives to a mixer and mix evenly to obtain a mixture; S2. Add the mixture to a twin-screw extruder and melt-extrude to obtain weather-resistant flame-retardant cable material.