Flame-retardant cable material as well as preparation method and application thereof

Abstract

The invention provides a flame-retardant cable material as well as a preparation method and application of the flame-retardant cable material, and belongs to the technical field of cable materials. Comprising the following raw material components in parts by weight: 60 parts of polyethylene, 8 to 12 parts of a thermoplastic elastomer, 10 to 15 parts of EVA-g-MAH, 5 to 8 parts of a modified SiO2-Al (OH) 3 flame retardant, 1 to 2 parts of sodium stearate, 0.5 to 1 part of an antioxidant, 0.5 to 1 part of a light stabilizer and 0.3 to 0.5 part of zinc oxide activated azodicarbonamide, the modified SiO2-Al (OH) 3 flame retardant is prepared by coating Al (OH) 3 with SiO2 and then modifying with a titanate coupling agent. According to the invention, the prepared material has excellent flame retardant property and mechanical property.

Description

Technical Field

[0001] The invention belongs to the technical field of cable materials, and in particular relates to a flame retardant cable material and a preparation method and application thereof. Background Art

[0002] Cables include power cables, control cables, compensation cables, shielded cables, high-temperature cables, computer cables, signal cables, coaxial cables, fire-resistant cables, marine cables, mining cables, aluminum alloy cables, etc. They are all composed of single-strand or multi-strand wires and insulating sheath materials, and are used to connect circuits, electrical appliances, etc. Existing sheath materials usually obtain the flame retardant properties of the materials by adding flame retardants. Flame retardants are divided into inorganic flame retardants and organic flame retardants. Among them, inorganic flame retardant hydroxides such as aluminum hydroxide and magnesium hydroxide are widely used in the flame retardant enhancement of sheath materials because they have the three functions of flame retardancy, smoke elimination, and filling, and are low in price, chemically stable, inert, non-toxic, and will not produce secondary pollution. In the preparation process of existing sheath materials, a lightweight effect is also obtained by adding a foaming agent.

[0003] For example, the Chinese invention patent with publication number CN105175856A discloses a recycled polyolefin halogen-free flame-retardant environmentally friendly foamed plastic, which is composed of recycled polyolefin, environmentally friendly foaming agent, environmentally friendly foaming promoter, halogen-free flame retardant, environmentally friendly filler, environmentally friendly antioxidant, environmentally friendly lubricant, and environmentally friendly colorant; the foam is light in weight, halogen-free flame-retardant, and green and environmentally friendly; it can be used as a cable filling material to reduce the production cost of the cable. However, the use of a foaming agent will increase the porosity of the material, indirectly leading to a decrease in the mechanical properties and flame retardant properties of the material. Summary of the invention

[0004] In order to solve the problems existing in the background technology, the present invention provides a flame retardant cable material and a preparation method and application thereof, so as to ensure that the prepared material has both excellent flame retardant properties and mechanical properties (tensile strength).

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A flame retardant cable material, comprising the following raw material components by weight: 60 parts of polyethylene, 8-12 parts of thermoplastic elastomer, 10-15 parts of EVA-g-MAH, 5-8 parts of modified SiO2-Al(OH)3 flame retardant, 1-2 parts of sodium stearate, 0.5-1 parts of antioxidant, 0.5-1 parts of light stabilizer and 0.3-0.5 parts of zinc oxide activated azodicarbonamide;

[0007] The modified SiO2-Al(OH)3 flame retardant is prepared by coating Al(OH)3 with SiO2 and then modifying it with a titanate coupling agent.

[0008] Further, the preparation method of the modified SiO2-Al(OH)3 flame retardant is as follows:

[0009] A1. Weigh 13.5 g of aluminum chloride, dissolve it in 1000 mL of water, add 145 - 155 mL of ammonia water with a concentration of 2 mol / L, and stir for 10 min to obtain an aluminum hydroxide slurry;

[0010] A2. Add fluorosilicic acid with a mass fraction of 12% into a plastic beaker, stir at room temperature, dropwise add ammonia water until pH = 3.5 - 4.0, then add an additive until pH = 6.0 - 6.5, and then add a precipitant until it is in excess. Stir for 30 min, let it stand for 24 h, filter to remove the residue, and obtain a purified (NH4)2SiF6 solution;

[0011] A3. By volume fraction, take 80 parts of the aluminum hydroxide slurry, ultrasonically disperse it for 1 h, place it in a constant temperature water bath at 60 - 70 °C and heat it. First, add 3 parts of the purified (NH4)2SiF6 solution. After the temperature rises to 60 - 70 °C, then dropwise add 6 - 7 parts of the purified (NH4)2SiF6 solution and 3.8 - 4.2 parts of ammonia water with a concentration of 2 mol / L. After the dropping is completed, stir for 40 min, then age, filter, wash, and vacuum dry to obtain SiO2-Al(OH)3 powder;

[0012] A4. Use a titanate coupling agent to perform surface modification on the SiO2-Al(OH)3 powder to obtain the modified SiO2-Al(OH)3 flame retardant.

[0013] Further, the additive uses a sodium hydroxide solution with a mass fraction of 9 - 12%.

[0014] Further, the precipitant uses a calcium chloride solution with a mass fraction of 2 - 3%.

[0015] Further, the specific operation steps of A4 are as follows: Place the SiO2-Al(OH)3 powder in a vacuum drying oven and dry it for 12 h, then take it out and dissolve it in an acetone solution, stir evenly to obtain a particle solution; Mix and stir the titanate coupling agent with acetone, then add isopropanol and stir evenly to obtain a modified solution; Mix the particle solution and the modified solution, ultrasonically oscillate in an ultrasonic cleaner for a certain time, fully mix them, then dry them in a vacuum drying oven at 80 °C, grind and sieve to obtain the modified SiO2-Al(OH)3 flame retardant.

[0016] Further, the preparation method of the zinc oxide-activated azodicarbonamide is as follows: Mix azodicarbonamide and zinc oxide in a mass ratio of (9 - 10):1 to obtain it.

[0017] Further, the antioxidant includes antioxidant CA and / or antioxidant 330.

[0018] Furthermore, the light stabilizer includes UV-944 and / or UV-119.

[0019] A method for preparing the flame-retardant cable material comprises the following steps:

[0020] S1. Add polyethylene, thermoplastic elastomer, EVA-g-MAH, modified SiO2-Al(OH)3 flame retardant, sodium stearate, antioxidant, light stabilizer and zinc oxide activated azodicarbonamide into a high-speed mixer, heat to 120-135° C., mix for 40-60 minutes, and let stand for 2-3 hours to obtain a mixture;

[0021] S2, adding the mixture into a twin-screw extruder for extrusion granulation, setting the extrusion temperature of the twin-screw extruder to 170-195° C., the screw speed to 120-130 r / min, and cooling the pellets to room temperature to obtain the flame-retardant cable material.

[0022] An application of the flame-retardant cable material is used for preparing cables.

[0023] This application has the following beneficial effects:

[0024] 1. The substrate of the present invention is polyethylene, thermoplastic elastomer and EVA-g-MAH. The three are used in combination, and through their respective characteristics and mutual synergy, the mechanical properties (tensile strength) of the obtained material can be effectively improved;

[0025] The addition of zinc oxide activated azodicarbonamide can increase the porosity of the material, provide a larger surface area, provide more abundant sites for the cross-linking of the modified SiO2-Al(OH)3 flame retardant and the substrate, improve the cross-linking structure of the modified SiO2-Al(OH)3 flame retardant and the substrate, and thus improve the mechanical properties (tensile strength) of the material; more cross-linking sites optimize the distribution and action efficiency of the modified SiO2-Al(OH)3 flame retardant, which is beneficial for the modified SiO2-Al(OH)3 flame retardant to play a more effective role and improve the flame retardant properties; experimental verification shows that the addition of zinc oxide activated azodicarbonamide can work synergistically with the modified SiO2-Al(OH)3 flame retardant to synergistically improve the mechanical properties (tensile strength) and flame retardant properties of the obtained material.

[0026] 2. In the preparation of zinc oxide activated azodicarbonamide, the addition of zinc oxide can, on the one hand, serve as a filler to enhance the mechanical properties of the material, including tensile strength, to a certain extent; on the other hand, it can reduce the starting temperature of thermal decomposition of azodicarbonamide, ensuring that the porosity is effectively improved within the limited temperature of the extrusion granulation of the present invention.

[0027] 3. In the preparation of the modified SiO2-Al(OH)3 flame retardant, Al(OH)3 mainly achieves flame retardant performance by absorbing heat, diluting the oxygen concentration, forming a protective layer, etc.;

[0028] SiO2 coating can inhibit the crystal form transformation of Al(OH)3 at high temperatures and prevent the decline of flame retardant performance caused by phase change; at the same time, the SiO2 coating layer is tightly combined with Al(OH)3 through chemical bonds or intermolecular forces, enhancing the cohesive force of the material and improving the tensile strength. The microstructure formed by the SiO2 coating layer on the surface of Al(OH)3 can also provide an additional mechanical locking effect, enhancing the friction with the substrate, thereby improving the tensile strength of the material;

[0029] Using a monoalkoxy titanate coupling agent for surface modification can effectively improve the dispersibility and compatibility of the flame retardant in the substrate, thereby further improving the mechanical properties and flame retardant properties of the material; verified by experiments, the SiO2 coating and the modification with the monoalkoxy titanate coupling agent can work synergistically to synergistically improve the mechanical properties (tensile strength) and flame retardant properties of the prepared material. Description of the Drawings

[0030] Figure 1 The comparison trend chart of the tensile strength and the comparison trend chart of the oxygen index of the flame retardant cable materials prepared in Examples 1-9 of the present invention;

[0031] Figure 2 The comparison trend chart of the tensile strength and the comparison trend chart of the oxygen index of the flame retardant cable materials prepared in Example 1 and Comparative Examples 1-8 of the present invention. Detailed Embodiments

[0032] The following further describes the present application in detail with reference to examples.

[0033] The raw materials of the examples and comparative examples of the present application are all ordinary commercially available except as otherwise specified.

[0034] Example 1: A flame retardant cable material, by weight, includes the following raw material components: 60 parts of polyethylene, 10 parts of thermoplastic elastomer, 12 parts of EVA-g-MAH, 6 parts of modified SiO2-Al(OH)3 flame retardant, 1.5 parts of sodium stearate, 0.6 part of antioxidant, 0.7 part of light stabilizer, and 0.4 part of zinc oxide-activated azodicarbonamide.

[0035] Among them, polyethylene (DFDA-7042) was purchased from Dongguan Yilong Plastic Co., Ltd. Thermoplastic elastomer (TPEE-4069) was purchased from Dongguan Zhongyuan Plastic Raw Materials Co., Ltd. EVA-g-MAH (28% high VA content maleic anhydride grafted EVA) was purchased from Dongguan Shenghao Plastic Raw Materials Co., Ltd. Sodium stearate (effective substance content 99.9%) was purchased from Guangzhou Bofeng Chemical Technology Co., Ltd. The antioxidant used was antioxidant 330 (RIANOXR 330 industrial grade). The light stabilizer used was UV-119 (BASF).

[0036] The preparation method of zinc oxide-activated azodicarbonamide is as follows: Mix azodicarbonamide and zinc oxide in a mass ratio of 9.5:1 to obtain it. Among them, zinc oxide (Nanhua brand) was purchased from Dongguan Xinmate Industrial Investment Co., Ltd. Azodicarbonamide was purchased from Jinan Huifeng Chemical Co., Ltd.

[0037] The preparation method of the modified SiO2-Al(OH)3 flame retardant is as follows:

[0038] A1. Weigh 13.5 g of aluminum chloride, dissolve it in 1000 mL of water, add 150 mL of ammonia water with a concentration of 2 mol / L, and stir for 10 min to obtain an aluminum hydroxide slurry. Among them, the aluminum chloride is anhydrous aluminum chloride (industrial grade / with a content of 95%), which was purchased from Tianjin Changda Technology Development Co., Ltd. The 2 mol / L ammonia water was prepared by mixing concentrated ammonia water and water by oneself.

[0039] A2. Add fluorosilicic acid with a mass fraction of 12% to a plastic beaker, stir at room temperature, dropwise add ammonia water with a concentration of 2 mol / L until the pH = 3.5 - 4.0, then add a sodium hydroxide solution with a mass fraction of 10% as an additive until the pH = 6.0 - 6.5, and then add a calcium chloride solution with a mass fraction of 2.5% as a precipitant until it is in excess, stir for 30 min, let it stand for 24 h, filter to remove the residue, and obtain a purified (NH4)2SiF6 solution. The fluorosilicic acid was purchased from Yuanyangguangming Chemical Co., Ltd., and the fluorosilicic acid with a mass fraction of 12% was prepared by mixing it with water by oneself. The sodium hydroxide solution with a mass fraction of 10% and the calcium chloride solution with a mass fraction of 2.5% were prepared by mixing them with water by oneself.

[0040] A3. By volume fraction, take 80 parts of the aluminum hydroxide slurry, ultrasonically disperse it for 1 h, place it in a constant temperature water bath at about 65 °C and heat it. First, add 3 parts of the purified (NH4)2SiF6 solution. After the temperature rises to about 65 °C, then dropwise add 6.5 parts of the purified (NH4)2SiF6 solution and 4 parts of ammonia water with a concentration of 2 mol / L. After the dropping is completed, stir for 40 min, then age, filter, wash, and vacuum dry to obtain SiO2-Al(OH)3 powder;

[0041] A4. By weight, 100 parts of SiO2 - Al(OH)3 powder were placed in a vacuum drying oven and dried for 12 h. After taking it out, it was dissolved in 180 parts of acetone solution and stirred evenly to obtain a particle solution; 2 parts of KH - 105 type monoalkoxy titanate coupling agent were mixed and stirred with 12 parts of acetone, then 2.5 parts of isopropanol were added and stirred evenly to obtain a modified solution; the particle solution was mixed with the modified solution, ultrasonically oscillated in an ultrasonic cleaner for 40 min, and then dried in a vacuum drying oven at 80 °C, and after grinding and sieving, the modified SiO2 - Al(OH)3 flame retardant was obtained. The KH - 105 type monoalkoxy titanate coupling agent was purchased from Nanjing Kuncheng Chemical Co., Ltd.

[0042] The preparation method of the flame - retardant cable material includes the following steps:

[0043] S1. Polyethylene, thermoplastic elastomer, EVA - g - MAH, modified SiO2 - Al(OH)3 flame retardant, sodium stearate, antioxidant, light stabilizer and zinc oxide activated azodicarbonamide were added to a high - speed mixer, heated to about 125 °C, mixed for 50 minutes, and then left standing for 2.5 hours to obtain a mixture;

[0044] S2. The mixture was added to a twin - screw extruder for extrusion granulation. The extrusion temperature of the twin - screw extruder was set at 170 - 195 °C. Specifically, the processing temperature control of each zone of the twin - screw extruder included Zone 1 to Zone 9, and they were 170 °C, 180 °C, 175 °C, 185 °C, 195 °C, 195 °C, 185 °C, 180 °C and 175 °C in sequence. The screw speed was 125 r / min. The pellets were cooled to room temperature to obtain the flame - retardant cable material.

[0045] Example 2: The difference between this example and Example 1 is that: a flame - retardant cable material, by weight, includes the following raw material components: 60 parts of polyethylene, 8 parts of thermoplastic elastomer, 10 parts of EVA - g - MAH, 5 parts of modified SiO2 - Al(OH)3 flame retardant, 1 part of sodium stearate, 0.5 part of antioxidant, 0.5 part of light stabilizer and 0.3 part of zinc oxide activated azodicarbonamide.

[0046] Example 3: The difference between this example and Example 1 is that: a flame - retardant cable material, by weight, includes the following raw material components: 60 parts of polyethylene, 12 parts of thermoplastic elastomer, 15 parts of EVA - g - MAH, 8 parts of modified SiO2 - Al(OH)3 flame retardant, 2 parts of sodium stearate, 1 part of antioxidant, 1 part of light stabilizer and 0.5 part of zinc oxide activated azodicarbonamide.

[0047] Example 4: The difference between this example and Example 1 is that the preparation method of the modified SiO2 - Al(OH)3 flame retardant is as follows:

[0048] A1. Weigh 13.5 g of aluminum chloride, dissolve it in 1000 mL of water, add 145 mL of 2 mol / L ammonia water, and stir for 10 min to obtain an aluminum hydroxide slurry.

[0049] A2. Add 12% fluorosilicic acid by mass fraction to a plastic beaker, stir at room temperature, dropwise add 2 mol / L ammonia water until the pH = 3.5 - 4.0, then add a 9% sodium hydroxide solution by mass fraction as an additive until the pH = 6.0 - 6.5, and then add a 2% calcium chloride solution by mass fraction as a precipitant until it is in excess. Stir for 30 min, let it stand for 24 h, filter to remove the residue, and obtain a purified (NH4)2SiF6 solution.

[0050] A3. By volume fraction, take 80 parts of the aluminum hydroxide slurry, ultrasonically disperse it for 1 h, place it in a constant temperature water bath at about 65 °C for heating. First, add 3 parts of the purified (NH4)2SiF6 solution. After the temperature rises to about 65 °C, then dropwise add 6 parts of the purified (NH4)2SiF6 solution and 3.8 parts of 2 mol / L ammonia water. After the dropping is completed, stir for 40 min, then age, filter, wash, and vacuum dry to obtain SiO2 - Al(OH)3 powder.

[0051] A4. By weight fraction, place 100 parts of SiO2 - Al(OH)3 powder in a vacuum drying oven and dry it for 12 h. Then take it out, dissolve it in 150 parts of acetone solution, and stir evenly to obtain a particle solution. Mix 1 part of KH - 105 type monoalkoxy titanate coupling agent with 10 parts of acetone and stir evenly, then add 2 parts of isopropanol and stir evenly to obtain a modified solution. Mix the particle solution and the modified solution, ultrasonically oscillate it in an ultrasonic cleaner for 30 min, then dry it at 80 °C in a vacuum drying oven, grind it, and sieve it to obtain the modified SiO2 - Al(OH)3 flame retardant.

[0052] Example 5: The difference between this example and Example 1 is that the preparation method of the modified SiO2 - Al(OH)3 flame retardant is as follows:

[0053] A1. Weigh 13.5 g of aluminum chloride, dissolve it in 1000 mL of water, add 155 mL of 2 mol / L ammonia water, and stir for 10 min to obtain an aluminum hydroxide slurry.

[0054] A2. Add fluosilicic acid with a mass fraction of 12% into a plastic beaker, stir at room temperature, add ammonia water with a concentration of 2 mol / L dropwise until the pH = 3.5 - 4.0, then add sodium hydroxide solution with a mass fraction of 12% as an additive until the pH = 6.0 - 6.5, then add calcium chloride solution with a mass fraction of 3% as a precipitant until in excess, stir for 30 min, let stand for 24 h, filter to remove the residue, and obtain the purified (NH4)2SiF6 solution.

[0055] A3. By volume fraction, take 80 parts of the aluminum hydroxide slurry, ultrasonically disperse it for 1 h, place it in a constant temperature water bath at about 65 °C to heat, first add 3 parts of the purified (NH4)2SiF6 solution, after the temperature rises to about 65 °C, then add 7 parts of the purified (NH4)2SiF6 solution and 4.2 parts of ammonia water with a concentration of 2 mol / L dropwise. After the dropwise addition is completed, stir for 40 min, then age, filter, wash, and vacuum dry to obtain the SiO2 - Al(OH)3 powder.

[0056] A4. By weight fraction, place 100 parts of the SiO2 - Al(OH)3 powder in a vacuum drying oven and dry it for 12 h, then take it out and dissolve it in 200 parts of acetone solution, stir evenly to obtain a particle liquid; mix 5 parts of KH - 105 type monoalkoxy titanate coupling agent with 15 parts of acetone and stir, then add 3 parts of isopropanol and stir evenly to obtain a modified liquid; mix the particle liquid and the modified liquid, ultrasonically oscillate in an ultrasonic cleaner for 50 min, then dry it in a vacuum drying oven at 80 °C, grind and sieve to obtain the modified SiO2 - Al(OH)3 flame retardant.

[0057] Example 6: The difference between this example and Example 1 is that the preparation method of zinc oxide - activated azodicarbonamide is as follows: Mix azodicarbonamide and zinc oxide according to a mass ratio of 9:1 to obtain it.

[0058] Example 7: The difference between this example and Example 1 is that the preparation method of zinc oxide - activated azodicarbonamide is as follows: Mix azodicarbonamide and zinc oxide according to a mass ratio of 10:1 to obtain it.

[0059] Example 8: The difference between this example and Example 1 is that the preparation method of the flame - retardant cable material includes the following steps:

[0060] S1. Add polyethylene, thermoplastic elastomer, EVA - g - MAH, modified SiO2 - Al(OH)3 flame retardant, sodium stearate, antioxidant, light stabilizer, and zinc oxide - activated azodicarbonamide into a high - speed mixer, heat up to 120 °C, mix for 40 minutes, then let stand for 2 hours to obtain a mixture.

[0061] S2. Add the mixture into a twin-screw extruder for extrusion granulation. Set the extrusion temperature of the twin-screw extruder at 170 - 195°C. Specifically, the processing temperature control of each zone of the twin-screw extruder includes Zone 1 to Zone 9, which are 170°C, 180°C, 175°C, 185°C, 195°C, 195°C, 185°C, 180°C, and 175°C in sequence. The screw speed is 120 r / min. Cool the pellets to room temperature to obtain the flame-retardant cable material.

[0062] Example 9: The difference between this example and Example 1 lies in that the preparation method of the flame-retardant cable material includes the following steps:

[0063] S1. Add polyethylene, thermoplastic elastomer, EVA-g-MAH, modified SiO2 - Al(OH)3 flame retardant, sodium stearate, antioxidant, light stabilizer, and zinc oxide-activated azodicarbonamide into a high-speed mixer. Heat up to 135°C, mix for 60 minutes, and then let it stand for 3 hours to obtain a mixture.

[0064] S2. Add the mixture into a twin-screw extruder for extrusion granulation. Set the extrusion temperature of the twin-screw extruder at 170 - 195°C. Specifically, the processing temperature control of each zone of the twin-screw extruder includes Zone 1 to Zone 9, which are 170°C, 180°C, 175°C, 185°C, 195°C, 195°C, 185°C, 180°C, and 175°C in sequence. The screw speed is 130 r / min. Cool the pellets to room temperature to obtain the flame-retardant cable material.

[0065] Comparative Example 1: The difference between this comparative example and Example 1 lies in that zinc oxide is deleted, that is, zinc oxide-activated azodicarbonamide is replaced by azodicarbonamide.

[0066] Specifically, a flame-retardant cable material, by weight, includes the following raw material components: 60 parts of polyethylene, 10 parts of thermoplastic elastomer, 12 parts of EVA-g-MAH, 6 parts of modified SiO2 - Al(OH)3 flame retardant, 1.5 parts of sodium stearate, 0.6 part of antioxidant, 0.7 part of light stabilizer, and 0.4 part of azodicarbonamide.

[0067] Comparative Example 2: The difference between this comparative example and Example 1 lies in that zinc oxide-activated azodicarbonamide is deleted.

[0068] Specifically, a flame-retardant cable material, by weight, includes the following raw material components: 60 parts of polyethylene, 10 parts of thermoplastic elastomer, 12 parts of EVA-g-MAH, 6 parts of modified SiO2 - Al(OH)3 flame retardant, 1.5 parts of sodium stearate, 0.6 part of antioxidant, and 0.7 part of light stabilizer.

[0069] Comparative Example 3: The difference between this comparative example and Example 1 is that no modification treatment is performed during the preparation of the flame retardant; that is, the modified SiO2-Al(OH)3 flame retardant is replaced by SiO2-Al(OH)3 powder.

[0070] Specifically, a flame-retardant cable material includes the following raw material components by weight: 60 parts of polyethylene, 10 parts of thermoplastic elastomer, 12 parts of EVA-g-MAH, 6 parts of SiO2-Al(OH)3 powder, 1.5 parts of sodium stearate, 0.6 parts of antioxidant, 0.7 parts of light stabilizer and 0.4 parts of zinc oxide activated azodicarbonamide.

[0071] The preparation method of SiO2-Al(OH)3 powder is as follows:

[0072] A1. Weigh 13.5 g of aluminum chloride, dissolve it in 1000 mL of water, add 150 mL of 2 mol / L ammonia water, stir for 10 min, and obtain aluminum hydroxide slurry.

[0073] A2. Add 12% by mass fluorosilicic acid into a plastic beaker, stir at room temperature, add 2 mol / L ammonia water dropwise until pH = 3.5-4.0, then add 10% by mass sodium hydroxide solution as an additive until pH = 6.0-6.5, then add 2.5% by mass calcium chloride solution as a precipitant until excess, stir for 30 minutes, let stand for 24 hours, filter and remove slag to obtain (NH4)2SiF6 purified solution.

[0074] A3. Take 80 parts of the aluminum hydroxide slurry by volume, ultrasonically disperse it for 1 hour, place it in a constant temperature water bath at about 65°C and heat it. First add 3 parts of the (NH4)2SiF6 purification liquid. After the temperature rises to about 65°C, add 6.5 parts of the (NH4)2SiF6 purification liquid and 4 parts of 2 mol / L ammonia water. After the addition is complete, stir for 40 minutes, then age, filter, wash and vacuum dry to obtain SiO2-Al(OH)3 powder.

[0075] Comparative Example 4: The difference between this comparative example and Example 1 is that: in the preparation of the flame retardant, no coating treatment is performed; that is, the modified SiO2-Al(OH)3 flame retardant is replaced by modified Al(OH)3 powder.

[0076] Specifically, a flame-retardant cable material includes the following raw material components by weight: 60 parts of polyethylene, 10 parts of thermoplastic elastomer, 12 parts of EVA-g-MAH, 6 parts of modified Al(OH)3 powder, 1.5 parts of sodium stearate, 0.6 parts of antioxidant, 0.7 parts of light stabilizer and 0.4 parts of zinc oxide activated azodicarbonamide.

[0077] The preparation method of the modified Al(OH)3 powder is as follows:

[0078] A1. Weigh 13.5 g of aluminum chloride, dissolve it in 1000 mL of water, add 150 mL of ammonia water with a concentration of 2 mol / L, stir for 10 min to obtain an aluminum hydroxide slurry, and obtain Al(OH)3 powder through vacuum drying.

[0079] A2. By weight, place 100 parts of Al(OH)3 powder in a vacuum drying oven and dry for 12 h, then take it out and dissolve it in 180 parts of acetone solution, stir evenly to obtain a particle liquid; mix 2 parts of KH-105 type monoalkoxy titanate coupling agent with 12 parts of acetone and stir, then add 2.5 parts of isopropanol and stir evenly to obtain a modified liquid; mix the particle liquid and the modified liquid, perform ultrasonic oscillation in an ultrasonic cleaner for 40 min, then dry at 80 °C in a vacuum drying oven, and obtain the modified Al(OH)3 powder through grinding and sieving.

[0080] Comparative Example 5: The difference between this comparative example and Example 1 is that in the preparation of the flame retardant, neither coating treatment nor modification treatment is performed; that is, the modified SiO2-Al(OH)3 flame retardant is replaced with Al(OH)3 powder.

[0081] Specifically, a flame-retardant cable material, by weight, includes the following raw material components: 60 parts of polyethylene, 10 parts of thermoplastic elastomer, 12 parts of EVA-g-MAH, 6 parts of Al(OH)3 powder, 1.5 parts of sodium stearate, 0.6 part of antioxidant, 0.7 part of light stabilizer, and 0.4 part of zinc oxide-activated azodicarbonamide.

[0082] The preparation method of Al(OH)3 powder is as follows: Weigh 13.5 g of aluminum chloride, dissolve it in 1000 mL of water, add 150 mL of ammonia water with a concentration of 2 mol / L, stir for 10 min to obtain an aluminum hydroxide slurry, and obtain Al(OH)3 powder through vacuum drying.

[0083] Comparative Example 6: The difference between this comparative example and Example 1 is that zinc oxide-activated azodicarbonamide is deleted, and in the preparation of the flame retardant, no modification treatment is performed (that is, the modified SiO2-Al(OH)3 flame retardant is replaced with SiO2-Al(OH)3 powder).

[0084] Specifically, a flame-retardant cable material, by weight, includes the following raw material components: 60 parts of polyethylene, 10 parts of thermoplastic elastomer, 12 parts of EVA-g-MAH, 6 parts of SiO2-Al(OH)3 powder, 1.5 parts of sodium stearate, 0.6 part of antioxidant, and 0.7 part of light stabilizer.

[0085] Comparative Example 7: The difference between this comparative example and Example 1 is that zinc oxide-activated azodicarbonamide is deleted, and no coating treatment is performed in the preparation of the flame retardant (i.e., the modified SiO2-Al(OH)3 flame retardant is replaced by modified Al(OH)3 powder).

[0086] Specifically, a flame-retardant cable material includes the following raw material components by weight: 60 parts of polyethylene, 10 parts of thermoplastic elastomer, 12 parts of EVA-g-MAH, 6 parts of modified Al(OH)3 powder, 1.5 parts of sodium stearate, 0.6 parts of antioxidant and 0.7 parts of light stabilizer.

[0087] Comparative Example 8: The difference between this comparative example and Example 1 is that zinc oxide-activated azodicarbonamide is deleted, and neither coating treatment nor modification treatment is performed in the preparation of the flame retardant (i.e., the modified SiO2-Al(OH)3 flame retardant is replaced by Al(OH)3 powder).

[0088] Specifically, a flame-retardant cable material includes the following raw material components by weight: 60 parts of polyethylene, 10 parts of thermoplastic elastomer, 12 parts of EVA-g-MAH, 6 parts of Al(OH)3 powder, 1.5 parts of sodium stearate, 0.6 parts of antioxidant and 0.7 parts of light stabilizer.

[0089] Test example 1: Test item: mechanical properties-tensile strength.

[0090] Test objects: Flame-retardant cable materials were prepared according to Examples 1-9 and Comparative Examples 1-8.

[0091] Test basis: Test according to the method required by GB / T 1040.1-2018.

[0092] Test results: See Table 1.

[0093] Test example 2: Test item: flame retardant performance-oxygen index.

[0094] Test objects: Flame-retardant cable materials were prepared according to Examples 1-9 and Comparative Examples 1-8.

[0095] Test basis: Test according to the method required by GB / T 2406.2-2009.

[0096] Test results: See Table 1.

[0097] Table 1. Test data of test example 1 and test example 2

[0098] Tensile strength / MPa Oxygen index / % Example 1 23.9 37 Example 2 23.6 36 Example 3 24.3 36 Example 4 23.8 37 Example 5 23.6 38 Example 6 23.7 37 Example 7 24.1 36 Example 8 24.3 37 Example 9 23.7 38 Comparative Example 1 23.0 36 Comparative Example 2 22.9 35 Comparative Example 3 17.1 27 Comparative Example 4 20.1 30 Comparative Example 5 15.0 22 Comparative Example 6 19.0 30 Comparative Example 7 19.5 29 Comparative Example 8 16.9 25

[0099] Result analysis: Analyze Examples 1-9 and combine the data in Table 1 and Figure 1It can be seen that the material prepared by the present invention has both excellent mechanical properties and flame retardancy, with a tensile strength of more than 23.6 MPa and an oxygen index of more than 36%.

[0100] Analyze Example 1 and Comparative Examples 1-8 and combine the data in Table 1 and Figure 2 It can be seen that in Comparative Example 8, Al(OH)3 powder was directly used as the flame retardant, and the tensile strength of the prepared material was 16.9 MPa and the oxygen index was 25%; compared with Comparative Example 8, in Comparative Example 6, SiO2 was used to coat Al(OH)3, and the tensile strength of the prepared material was 19.0 MPa and the oxygen index was 30%; compared with Comparative Example 8, in Comparative Example 7, a titanate coupling agent was used to modify the surface of Al(OH)3 powder, and the tensile strength of the prepared material was 19.5 MPa and the oxygen index was 29%; compared with Comparative Example 8, in Comparative Example 2, both SiO2 was used to coat Al(OH)3 and a titanate coupling agent was used to modify the surface, and the tensile strength of the prepared material was 22.9 MPa and the oxygen index was 35%; it shows that the coating treatment with SiO2 and the modification treatment with the titanate coupling agent can respectively improve the mechanical properties (tensile strength) and flame retardancy (oxygen index) of the prepared material, and there is a synergistic effect between the two, which can also synergistically improve the mechanical properties (tensile strength) and flame retardancy (oxygen index) of the prepared material.

[0101] In Comparative Example 8, Al(OH)3 powder was used as the flame retardant, and the tensile strength of the prepared material was 16.9 MPa and the oxygen index was 25%; compared with Comparative Example 8, in Comparative Example 5, zinc oxide-activated azodicarbonamide was added, and the tensile strength of the prepared material was 15.0 MPa and the oxygen index was 22%, both of which decreased; it shows that when the flame retardant is Al(OH)3 powder, the addition of the foaming agent zinc oxide-activated azodicarbonamide will cause the mechanical properties (tensile strength) and flame retardancy (oxygen index) of the prepared material to decrease.

[0102] Based on Comparative Example 5, that is, in the presence of the foaming agent zinc oxide-activated azodicarbonamide, compared with Comparative Example 5, Comparative Example 3 used SiO2 to coat Al(OH)3, and the tensile strength of the obtained material was 17.1 MPa and the oxygen index was 27%; compared with Comparative Example 5, Comparative Example 4 used a titanate coupling agent to modify the surface of Al(OH)3 powder, and the tensile strength of the obtained material was 20.1 MPa and the oxygen index was 30%; compared with Comparative Example 5, Example 1 used SiO2 to coat Al(OH)3 and used a titanate coupling agent to modify the surface, and the tensile strength of the obtained material was 23.9 MPa and the oxygen index was 37%; it shows that in the presence of the foaming agent zinc oxide-activated azodicarbonamide, the coating treatment of Al(OH)3 with SiO2 and the modification treatment with the titanate coupling agent can still improve the mechanical properties (tensile strength) and flame retardant properties (oxygen index) of the obtained material respectively, and there is a synergistic effect between the two, which can synergistically improve the mechanical properties (tensile strength) and flame retardant properties (oxygen index) of the obtained material.

[0103] Comparative Example 2 used a modified SiO2-Al(OH)3 flame retardant, and the tensile strength of the obtained material was 22.9 MPa and the oxygen index was 35%; compared with Comparative Example 2, Example 1 added the foaming agent zinc oxide-activated azodicarbonamide, and the tensile strength of the obtained material was 23.9 MPa and the oxygen index was 37%, both increased; it shows that when the flame retardant is a modified SiO2-Al(OH)3 flame retardant, the addition of the foaming agent zinc oxide-activated azodicarbonamide will not reduce the mechanical properties (tensile strength) and flame retardant properties (oxygen index) of the obtained material, but will improve the mechanical properties (tensile strength) and flame retardant properties (oxygen index) of the obtained material.

[0104] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, without contradiction, they can be combined in any suitable way. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0105] In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A flame-retardant cable material, characterized in that, By weight parts, it includes the following raw material components: 60 parts of polyethylene, 8 - 12 parts of thermoplastic elastomer, 10 - 15 parts of EVA-g-MAH, 15 - 20 parts of modified SiO2-Al(OH)3 flame retardant, 1 - 2 parts of sodium stearate, 0.5 - 1 part of antioxidant, 0.5 - 1 part of light stabilizer, and 0.3 - 0.5 part of zinc oxide-activated azodicarbonamide; The modified SiO2-Al(OH)3 flame retardant is prepared by coating Al(OH)3 with SiO2 and then modifying it with a titanate coupling agent.

2. The flame-retardant cable material according to claim 1, characterized in that, The preparation method of the modified SiO2-Al(OH)3 flame retardant is as follows: A1. Weigh 13.5 g of aluminum chloride, dissolve it in 1000 mL of water, add 145 - 155 mL of ammonia water with a concentration of 2 mol / L, and stir for 10 min to obtain an aluminum hydroxide slurry; A2. Add hydrofluosilicic acid with a mass fraction of 12% into a beaker, stir at room temperature, add ammonia water until pH = 3.5 - 4.0, then add an additive until pH = 6.0 - 6.5, then add a precipitant until it is in excess, stir for 30 min, let it stand for 24 h, filter to obtain a purified (NH4)2SiF6 solution; A3. By volume parts, take 80 parts of the aluminum hydroxide slurry, ultrasonically disperse it for 1 h, place it in a constant temperature water bath at 60 - 70 °C and heat it. First, add 3 parts of the purified (NH4)2SiF6 solution. After the temperature rises to 60 - 70 °C, then dropwise add 6 - 7 parts of the purified (NH4)2SiF6 solution and 3.8 - 4.2 parts of ammonia water with a concentration of 2 mol / L, stir for 40 min, then age, filter, wash, and vacuum dry to obtain SiO2-Al(OH)3 powder; A4. Use a titanate coupling agent to conduct surface modification treatment on the SiO2-Al(OH)3 powder to obtain the modified SiO2-Al(OH)3 flame retardant.

3. The flame-retardant cable material according to claim 2, wherein In A2, the additive uses a sodium hydroxide solution with a mass fraction of 9 - 12%.

4. The flame-retardant cable material according to claim 2, characterized in that, In A2, the precipitant uses a calcium chloride solution with a mass fraction of 2 - 3%.

5. The flame-retardant cable material according to claim 2, wherein, The specific operation steps of A4 are as follows: Place the SiO2-Al(OH)3 powder in a vacuum drying oven and dry it for 12 h, then take it out and dissolve it in an acetone solution, stir evenly to obtain a particle solution; Mix the titanate coupling agent with acetone, then add isopropanol and stir evenly to obtain a modified solution; Mix the particle solution and the modified solution, ultrasonically oscillate, after mixing evenly, dry it in a vacuum drying oven at 80 °C, grind it, and sieve it to obtain the modified SiO2-Al(OH)3 flame retardant.

6. The flame-retardant cable material according to claim 1, wherein The preparation method of the zinc oxide-activated azodicarbonamide is as follows: Mix azodicarbonamide and zinc oxide according to a mass ratio of (9 - 10):1 to obtain it.

7. The flame-retardant cable material according to claim 1, characterized in that, The antioxidant includes antioxidant CA and / or antioxidant 330.

8. The flame-retardant cable material according to claim 1, characterized in that, The light stabilizer includes UV-944 and / or UV-119.

9. A method for preparing a flame-retardant cable material according to any one of claims 1-8, characterized in that, It includes the following steps: S1. Add polyethylene, thermoplastic elastomer, EVA-g-MAH, modified SiO2-Al(OH)3 flame retardant, sodium stearate, antioxidant, light stabilizer and zinc oxide activated azodicarbonamide into a mixer, heat up to 120 - 135 °C, mix for 40 - 60 min, and then let it stand for 2 - 3 h to obtain a mixture; S2. Set the extrusion temperature of the twin-screw extruder to 170 - 195 °C and the screw speed to 120 - 130 r / min. Add the said mixture into the twin-screw extruder for extrusion granulation, and cool the granulated material to room temperature to obtain the said flame-retardant cable material.

10. Use of a flame-retardant cable material according to any one of claims 1-8, characterized in that, It is used for preparing cables.

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