A preparation method of crack-resistant modified EVA cable material

Abstract

The invention relates to the technical field of polymer materials and discloses a preparation method of a crack-resistant modified EVA cable material. The method comprises the following steps: using maleic anhydride, N,N-bis(2-aminoethyl)methylamine, benzyl chloride and HDPE as raw materials, preparing antibacterial modified HDPE through a one-step dehydration and ring closing method and a solution method; then using benzotriazole, bis(2-chloroethyl)amine, 3-chloropropyltrimethoxysilane and magnesium hydroxide as raw materials, preparing anti-ultraviolet modified magnesium hydroxide through a substitution reaction and a polymerization reaction; and finally using the antibacterial modified HDPE, EVA, anti-ultraviolet modified magnesium hydroxide, red phosphorus and the like as raw materials, preparing the crack-resistant modified EVA cable material through a melting method. The crack-resistant modified EVA cable material prepared by the method has good crack resistance, antibacterial performance, flame retardancy and anti-ultraviolet performance.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to a method for preparing crack-resistant modified EVA cable material. Background Art

[0002] EVA is a commonly used thermoplastic polymer material, formed by copolymerizing non-polar ethylene monomer and highly polar vinyl acetate monomer (VA) in a specific ratio. The introduction of vinyl acetate monomer into the molecular chain improves flexibility, impact resistance, filler compatibility, and heat sealing properties. It is widely used in functional films, packaging materials, electrical insulation, cable industry, hot melt adhesives, and biomedical devices. The presence of only three elements, C, H, and O, in the EVA molecular structure makes it highly flammable, releasing a large amount of heat and exhibiting severe melting during combustion. However, EVA possesses good insulation properties and excellent physical and mechanical properties.

[0003] For example, patent publication number CN116396551A discloses a polyethylene composition, its preparation method, and application. This invention utilizes high-density polyethylene, ethylene-vinyl acetate copolymer (EVA), EVA-g-NBR, flaky aluminum hydroxide, montmorillonite, a silane coupling agent, an initiator, and an antioxidant. The raw materials and formulation selected in this patent possess not only excellent mechanical and flame retardant properties, but also excellent oil resistance, making it ideal for use in cables exposed to long-term contact with paraffin oils. However, the cables produced using this invention are not suitable for use in damp or wet environments, as these environments can easily breed bacteria, shortening their service life. Furthermore, the cables exhibit poor UV resistance. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In view of the deficiencies in the prior art, the present invention provides a method for preparing a crack-resistant modified EVA cable material. The prepared modified EVA cable material has good antibacterial and anti-ultraviolet properties.

[0006] (2) Technical solution

[0007] A method for preparing a crack-resistant modified EVA cable material, the preparation method being as follows:

[0008] The antibacterial modified high-density polyethylene (HDPE) and ethylene-vinyl acetate copolymer (EVA) are uniformly mixed to obtain a premix, half of the premix is ​​taken and added to an open mill, and the temperature is raised to 90-110° C. The other half of the premix, anti-UV modified magnesium hydroxide, red phosphorus, superdispersant polyvinyl pyrrolidone, and antioxidant quercetin are evenly mixed and added to an open mill, and the mixture is mixed for 8-12 minutes and stirred for 3-7 minutes. Then, a curing agent diisopropyl peroxide (DCP) and a vulcanization accelerator triallyl isocyanurate (TAIC) are added and the mixture is mixed for another 3-7 minutes to obtain a rubber compound, which is placed in a flat vulcanizer, heated to 160-180° C., a pressure of 3-7 MPa, vulcanized for 15-25 minutes, and then cooled for 3-7 minutes to obtain a crack-resistant modified EVA cable material.

[0009] Preferably, the preparation method of the antibacterial modified HDPE is as follows:

[0010] S1. Add maleic anhydride to isopropanol solution, heat to 15-25°C, add N,N-bis(2-aminoethyl)methylamine dropwise thereto, keep warm and react for 0.5-1.5h, then add acetic anhydride and sodium acetate, heat to 25-30°C, react for 2-3h, filter, wash with deionized water, and dry at 40-50°C to obtain intermediate 1;

[0011] S2, benzyl chloride and intermediate 1 are added to N,N-dimethylformamide (DMF) solvent, and then ethyl acetate catalyst is added, the temperature is raised to 50-70°C, stirred and reacted for 5-7 hours, cooled to room temperature, precipitated with ether, and filtered to obtain quaternary ammonium salt-modified maleic anhydride;

[0012] S3. Add HDPE to xylene solution, heat to 130-140°C, stir until completely dissolved, then add quaternary ammonium salt modified maleic anhydride and benzoyl peroxide (BPO) initiator, react for 2-4 hours, cool to 20-30°C, filter, wash with acetone, and dry to obtain modified maleic anhydride grafted polyethylene.

[0013] Preferably, the preparation method of the UV-resistant modified magnesium hydroxide is as follows:

[0014] SS1. Add benzotriazole to ethanol solvent, stir to dissolve, add sodium hydroxide, stir, raise the temperature to 45-65°C, add bis(2-chloroethyl)amine, stir, continue to raise the temperature to 75-85°C, react for 22-26 hours, distill under reduced pressure, wash with hot deionized water, separate the layers, and dry with calcium chloride to obtain intermediate 2;

[0015] SS2, add intermediate 2 to ether solvent, introduce nitrogen, add 3-chloropropyltrimethoxysilane dropwise for 1-2 hours, raise the temperature to 30-40°C, react for 6-8 hours, let stand for 12-16 hours, filter, wash with anhydrous ether, and distill at low pressure to obtain benzotriazole modified silane coupling agent;

[0016] SS3. Dry the magnesium hydroxide in a drying oven, heat it to 100-120°C, dry it for 8-12 hours, cool it to room temperature, add it to deionized water, stir it for 8-12 minutes, then add the ethanol solution of benzotriazole-modified silane coupling agent, heat it to 30-50°C, stir and react for 20-40 minutes. After the reaction is completed, cool it to room temperature, filter, wash, dry, grind, and sieve to obtain modified magnesium hydroxide.

[0017] Preferably, the mass ratio of EVA, antibacterial modified HDPE, modified magnesium hydroxide, hyperdispersant polyvinyl pyrrolidone, antioxidant quercetin, DCP, and TAIC is 1:0.25-0.45:1.38-1.47:0.15-0.27:0.032-0.04:0.04-0.065:0.04-0.065.

[0018] Preferably, in step S1, the mass ratio of maleic anhydride, N,N-bis(2-aminoethyl)methylamine, acetic anhydride, and sodium acetate is 1:0.55-0.60:0.12-0.14:0.006-0.007.

[0019] Preferably, in step S2, the mass ratio of intermediate 1, benzyl chloride, and ethyl acetate is 1:0.36-0.55:0.1-0.2.

[0020] Preferably, in step S3, the mass ratio of HDPE, quaternary ammonium salt-modified maleic anhydride, maleic anhydride, and BPO is 1:0.02-0.1:0.02-0.1:0.005-0.03.

[0021] Preferably, in step SS1, the mass ratio of sodium hydroxide, bis(2-chloroethyl)amine, and benzotriazole is 0.4-0.45:0.45-0.65:1.

[0022] Preferably, in step SS2, the mass ratio of the intermediate 2:3-chloropropyltrimethoxysilane is 1:0.12-0.14.

[0023] Preferably, in step SS3, the mass ratio of magnesium hydroxide to modified silane coupling agent is 1:0.8-1.2.

[0024] (3) Beneficial technical effects

[0025] The invention uses maleic anhydride, N,N-bis(2-aminoethyl)methylamine, benzyl chloride and HDPE as raw materials, and prepares antibacterial modified HDPE through a one-step dehydration and ring closing method and a solution method. Then, using benzotriazole, bis(2-chloroethyl)amine, 3-chloropropyltrimethoxysilane and magnesium hydroxide as raw materials, and preparing anti-ultraviolet modified magnesium hydroxide through a substitution reaction and a polymerization reaction. Finally, using antibacterial modified HDPE, EVA, anti-ultraviolet modified magnesium hydroxide, red phosphorus and the like as raw materials, and preparing anti-cracking modified EVA cable material through a melting method.

[0026] The crack-resistant modified EVA cable material prepared by the present invention contains quaternary ammonium salt groups. The quaternary ammonium salt groups have positive charges and can be adsorbed on the surface of microorganisms to form micelles and gradually penetrate into the lipid layer and protein layer of the cell plasma, thereby changing the permeability of the cell membrane and causing the cell contents to extravasate, leading to the death of the microorganisms. At the same time, the quaternary ammonium salt groups coagulate proteins, denature enzymes and structural proteins, disrupt the metabolism of the microorganisms, and kill the microorganisms, thereby improving the antibacterial property of the cable.

[0027] The crack-resistant modified EVA cable material prepared by the present invention contains azo groups, which have the characteristics of photochromism and photoinduced cis-trans isomerization, and the azo groups have a clear absorption peak in the ultraviolet region (especially between 200-400nm). This is because the π electrons in the azo groups easily undergo transitions under ultraviolet light, from a lower energy level to a higher energy level. This transition absorbs ultraviolet light and reduces ultraviolet light penetration, thereby achieving an anti-ultraviolet effect. Introducing the azo groups into the cable material can improve the anti-ultraviolet performance of the cable material.

[0028] The crack-resistant modified EVA cable material prepared by the present invention contains HDPE. The vinyl acetate units contained in the EVA molecular chains can interact with the molecular chains in the HDPE to form a relatively tight compatibility interface. At the same time, the increase in the cross-linking degree between HDPE and EVA makes the slippage between the molecular chains more difficult, thereby improving the anti-cracking performance of the material.

[0029] The crack-resistant modified EVA cable material prepared by the present invention contains magnesium hydroxide and red phosphorus flame retardant. The magnesium hydroxide reduces the temperature of the cable matrix through the dehydration and heat absorption effect of the condensed phase, diluting the gaseous combustibles and oxygen concentration to achieve the purpose of flame retardancy and smoke suppression. At the same time, the cable contains phosphorus, nitrogen, and silicon elements. Nitrogen decomposes during combustion to produce a large amount of non-combustible gas, which can dilute the oxygen concentration around the composite material. Silicon can migrate to the outer surface of the material during combustion, and the Si-O bonds in its molecules are converted into Si-C bonds. The generated white combustion residue and carbide form a coating on the surface of the composite material, preventing the escape of combustion volatiles and preventing oxygen from contacting the matrix material, thereby improving the flame retardancy of the cable. Phosphorus releases a large amount of gas or high-density steam when heated or burned, which can dilute oxygen and gaseous combustibles in the air and reduce the surface temperature of the burning material, causing combustion to stop. The crack-resistant modified EVA cable material prepared by the present invention has good crack resistance, antibacterial properties, flame retardancy, and UV resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a preparation route for quaternary ammonium salt modified maleic anhydride;

[0031] Figure 2 This is a preparation route for benzotriazole-modified silane coupling agents. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] Example 1

[0034] (1) Add 50 g of maleic anhydride to 100 ml of isopropanol solution, heat to 15°C, add 30 g of N,N-bis(2-aminoethyl)methylamine dropwise thereto, add dropwise for 1 hour, keep warm and react for 0.5 hour, then add 7 g of acetic anhydride and 0.3 g of sodium acetate, heat to 30°C, react for 2 hours, filter, wash with deionized water, and dry at 50°C to obtain intermediate 1.

[0035] (2) Add 18 g of benzyl chloride and 50 g of intermediate 1 to 100 ml of N,N-dimethylformamide (DMF) solvent, then add 10 g of ethyl acetate catalyst, heat to 70 ° C, stir and react for 5 h, cool to room temperature, precipitate with ether, and filter to obtain quaternary ammonium salt modified maleic anhydride.

[0036] (3) Add 10 g of HDPE to 15 ml of xylene solution, heat to 140 °C, stir until completely dissolved, then add 0.2 g of quaternary ammonium salt modified maleic anhydride, 1 g of maleic anhydride and 0.1 g of benzoyl peroxide (BPO) initiator, react for 4 h, cool to 20 °C, filter, wash with acetone, and dry to obtain modified maleic anhydride grafted polyethylene.

[0037] (4) Add 10 g of benzotriazole to 50 ml of ethanol solvent, stir to dissolve, add 4.5 g of sodium hydroxide, stir, heat to 65 ° C, add 4 g of bis(2-chloroethyl)amine, stir, continue to heat to 80 ° C, react for 26 h, distill under reduced pressure, wash with hot deionized water, separate the layers, and dry with calcium chloride to obtain intermediate 2.

[0038] (5) Add 5 g of intermediate 2 to 20 ml of ether solvent, introduce nitrogen, add 0.6 g of 3-chloropropyltrimethoxysilane dropwise, add for 1.5 hours, heat to 40 ° C, react for 6 hours, let stand for 12 hours, filter, wash with anhydrous ether, and distill at low pressure to obtain benzotriazole modified silane coupling agent.

[0039] (6) 1 g of magnesium hydroxide was placed in a drying oven and dried, heated to 110° C., dried for 10 h, cooled to room temperature, added to deionized water, stirred for 10 min, and then added with 1.3 g of benzotriazole-modified silane coupling agent ethanol solution, heated to 40° C., stirred for 30 min, and after the reaction was completed, cooled to room temperature, filtered, washed, dried, ground, and sieved to obtain modified magnesium hydroxide.

[0040] (7) 4.5 g of antibacterial modified high-density polyethylene (HDPE) and 10 g of ethylene-vinyl acetate copolymer (EVA) were uniformly mixed to obtain a premix. Half of the premix was added to an open mill and heated to 90°C. The other half of the premix, 14.5 g of anti-UV modified magnesium hydroxide, 1 g of red phosphorus, 1.5 g of hyperdispersant polyvinyl pyrrolidone, and 0.32 g of antioxidant quercetin were mixed evenly and added to an open mill. The mixture was then mixed for 12 min and stirred for 5 min. 0.4 g of vulcanizing agent diisopropyl peroxide (DCP) and 0.5 g of vulcanization accelerator triallyl isocyanurate (TAIC) were added and the mixture was further mixed for 7 min. The mixed rubber was placed in a flat vulcanizer, heated to 160°C, pressure 3 MPa, vulcanized for 20 min, and cooled for 7 min to obtain anti-cracking modified EVA cable material.

[0041] Example 2

[0042] (1) Add 50 g of maleic anhydride to 100 ml of isopropanol solution, heat to 22 ° C, add 28 g of N, N-bis (2-aminoethyl) methylamine dropwise thereto, add dropwise for 0.75 h, keep warm and react for 0.5 h, then add 6 g of acetic anhydride and 0.31 g of sodium acetate, heat to 28 ° C, react for 2.5 h, filter, wash with deionized water, and dry at 45 ° C to obtain intermediate 1.

[0043] (2) Add 20 g of benzyl chloride and 50 g of intermediate 1 to 100 ml of DMF solvent, then add 7.5 g of ethyl acetate catalyst, heat to 60 ° C, stir and react for 5.7 hours, cool to room temperature, precipitate with ether, and filter to obtain quaternary ammonium salt modified maleic anhydride.

[0044] (3) Add 10 g of HDPE to 50 ml of xylene solution, heat to 132 °C, stir until completely dissolved, then add 0.22 g of quaternary ammonium salt modified maleic anhydride, 0.5 g of maleic anhydride and 0.05 g of BPO initiator, react for 2.4 h, cool to 25 °C, filter, wash with acetone, and dry to obtain modified maleic anhydride grafted polyethylene.

[0045] (4) Add 10 g of benzotriazole to 50 ml of ethanol solvent, stir to dissolve, add 4.3 g of sodium hydroxide, stir, heat to 48 ° C, add 4.8 g of bis(2-chloroethyl)amine, stir, continue to heat to 78 ° C, react for 24 h, distill under reduced pressure, wash with hot deionized water, separate the layers, and dry with calcium chloride to obtain intermediate 2.

[0046] (5) Add 10 g of intermediate 2 to 20 ml of ether solvent, introduce nitrogen, add 1.3 g of 3-chloropropyltrimethoxysilane dropwise, add for 1.2 h, heat to 35 ° C, react for 6.8 h, let stand for 16 h, filter, wash with anhydrous ether, and distill at low pressure to obtain benzotriazole modified silane coupling agent.

[0047] (6) 10 g of magnesium hydroxide was placed in a drying oven and dried, heated to 105 ° C., dried for 9 h, cooled to room temperature, added to deionized water, stirred for 10 min, and then added with 12 g of ethanol solution of benzotriazole-modified silane coupling agent, heated to 35 ° C., stirred for 24 min. After the reaction was completed, cooled to room temperature, filtered, washed, dried, ground, and sieved to obtain modified magnesium hydroxide.

[0048] (7) 3.5 g of antibacterial modified HDPE and 10 g of EVA were uniformly mixed to obtain a premix. Half of the premix was taken and added to an open mill and heated to 95°C. The other half of the premix, 13.5 g of anti-UV modified magnesium hydroxide, 1 g of red phosphorus, 0.35 g of a hyperdispersant, and 0.5 g of an antioxidant were mixed evenly and added to an open mill. The mixture was mixed for 9 minutes and stirred for 5 minutes. 0.6 g of a vulcanizing agent DCP and 0.4 g of a vulcanization accelerator TAIC were added and mixed for another 6 minutes. The mixed rubber was placed in a flat vulcanizer, heated to 165°C, a pressure of 4 MPa, vulcanized for 18 minutes, and then cooled for 6 minutes to obtain a crack-resistant modified EVA cable material.

[0049] Example 3

[0050] (1) Add 30 g of maleic anhydride to 100 ml of isopropanol solution, heat to 20°C, add 17.4 g of N,N-bis(2-aminoethyl)methylamine dropwise thereto, add dropwise for 0.75 h, keep warm and react for 1.2 h, then add 3.9 g of acetic anhydride and 0.195 g of sodium acetate, heat to 28°C, react for 2.8 h, filter, wash with deionized water, and dry at 44°C to obtain intermediate 1.

[0051] (2) 16.5 g of benzyl chloride and 30 g of intermediate 1 were added to 100 ml of DMF solvent, and 4.5 g of ethyl acetate catalyst was added. The temperature was raised to 55° C. and stirred for 5.7 h. The mixture was cooled to room temperature, precipitated with ether, and filtered to obtain quaternary ammonium salt-modified maleic anhydride.

[0052] (3) Add 10 g of HDPE to 50 ml of xylene solution, heat to 134 °C, stir until completely dissolved, then add 0.25 g of quaternary ammonium salt modified maleic anhydride, 0.3 g of maleic anhydride and 0.2 g of BPO initiator, react for 2.6 h, cool to 30 °C, filter, wash with acetone, and dry to obtain modified maleic anhydride grafted polyethylene.

[0053] (4) Add 10 g of benzotriazole to 50 ml of ethanol solvent, stir to dissolve, add 4.2 g of sodium hydroxide, stir, heat to 50 ° C, add 6.2 g of bis(2-chloroethyl)amine, stir, continue to heat to 80 ° C, react for 25 h, distill under reduced pressure, wash with hot deionized water, separate the layers, and dry with calcium chloride to obtain intermediate 2.

[0054] (5) Add 10 g of intermediate 2 to 50 ml of ether solvent, introduce nitrogen, add 1.2 g of 3-chloropropyltrimethoxysilane dropwise, add for 1 hour, heat to 38 ° C, react for 7 hours, let stand for 14 hours, filter, wash with anhydrous ether, and distill at low pressure to obtain benzotriazole modified silane coupling agent.

[0055] (6) 10 g of magnesium hydroxide was placed in a drying oven and dried, heated to 120 ° C, dried for 8 h, cooled to room temperature, added to deionized water, stirred for 12 min, and then added with 13 g of benzotriazole-modified silane coupling agent ethanol solution, heated to 40 ° C, stirred for 40 min, and after the reaction was completed, cooled to room temperature, filtered, washed, dried, ground, and sieved to obtain modified magnesium hydroxide.

[0056] (7) 3 g of antibacterial modified HDPE and 10 g of EVA were evenly mixed to obtain a premix. Half of the premix was added to an open mill and heated to 110°C. The other half of the premix, 12.5 g of anti-UV modified magnesium hydroxide, 1 g of red phosphorus, 2.5 g of a hyperdispersant, and 0.38 g of an antioxidant were evenly mixed and added to an open mill. The mixture was then mixed for 9 minutes and stirred for 3 minutes. 0.65 g of a vulcanizing agent DCP and 0.6 g of a vulcanization accelerator TAIC were then added and mixed for another 3.5 minutes. The mixed rubber was placed in a flat vulcanizer, heated to 178°C, at a pressure of 6.5 MPa, and vulcanized for 23 minutes. The mixture was then cooled for 4 minutes to obtain a crack-resistant modified EVA cable material.

[0057] Example 4

[0058] (1) Add 30 g of maleic anhydride to 100 ml of isopropanol solution, heat to 25°C, add 18 g of N,N-bis(2-aminoethyl)methylamine dropwise thereto, keep warm and react for 1.5 h, then add 3.9 g of acetic anhydride and 0.63 g of sodium acetate, heat to 30°C, react for 2 h, filter, wash with deionized water, and dry at 50°C to obtain intermediate 1.

[0059] (2) 10.8 g of benzyl chloride and 30 g of intermediate 1 were added to 100 ml of DMF solvent, and 3 g of ethyl acetate catalyst was added. The temperature was raised to 70 ° C. and stirred for 7 h. The mixture was cooled to room temperature, precipitated with ether, and filtered to obtain quaternary ammonium salt-modified maleic anhydride.

[0060] (3) Add 10 g of HDPE to 50 ml of xylene solution, heat to 140 °C, stir until completely dissolved, then add 1 g of quaternary ammonium salt modified maleic anhydride, 1 g of maleic anhydride and 0.3 g of BPO initiator, react for 4 h, cool to 30 °C, filter, wash with acetone, and dry to obtain modified maleic anhydride grafted polyethylene.

[0061] (4) Add 10 g of benzotriazole to 50 ml of ethanol solvent, stir to dissolve, add 4 g of sodium hydroxide, stir, heat to 65 ° C, add 6.5 g of bis(2-chloroethyl)amine, stir, continue to heat to 85 ° C, react for 22 h, distill under reduced pressure, wash with hot deionized water, separate the layers, and dry with calcium chloride to obtain intermediate 2.

[0062] (5) Add 10 g of intermediate 2 to 50 ml of ether solvent, introduce nitrogen, add 1.4 g of 3-chloropropyltrimethoxysilane dropwise, add dropwise for 2 h, raise the temperature to 40 ° C, react for 6 h, let stand for 16 h, filter, wash with anhydrous ether, and distill at low pressure to obtain benzotriazole modified silane coupling agent.

[0063] (6) 10 g of magnesium hydroxide was placed in a drying oven and dried, heated to 115 ° C., dried for 11 h, cooled to room temperature, added to deionized water, stirred for 11 min, and then added with 8 g of benzotriazole-modified silane coupling agent ethanol solution, heated to 45 ° C., stirred for 35 min. After the reaction was completed, cooled to room temperature, filtered, washed, dried, ground, and sieved to obtain modified magnesium hydroxide.

[0064] (7) 2.5 g of antibacterial modified HDPE and 10 g of EVA were uniformly mixed to obtain a premix. Half of the premix was added to an open mill and heated to 110°C. The other half of the premix, 13 g of anti-UV modified magnesium hydroxide, 1 g of red phosphorus, 2.7 g of a hyperdispersant, and 0.4 g of an antioxidant were mixed evenly and added to an open mill. The mixture was then mixed for 8 min and stirred for 5 min. 0.5 g of a vulcanizing agent DCP and 0.65 g of a vulcanization accelerator TAIC were then added and the mixture was further mixed for 5 min. The mixed rubber was placed in a flat vulcanizer, heated to 180°C, pressure 7 MPa, vulcanized for 25 min, and cooled for 4.5 min to obtain a crack-resistant modified EVA cable material.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 1 is that no antimicrobial modified HDPE is added in Comparative Example 1.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 1 is that no anti-ultraviolet modified magnesium hydroxide is added in Comparative Example 2.

[0069] Comparative Example 3

[0070] The difference between this comparative example and Example 1 is that the antibacterial modified HDPE added in Comparative Example 3 is replaced by HDPE, and the anti-ultraviolet modified magnesium hydroxide added is replaced by magnesium hydroxide.

[0071] Cracking resistance test

[0072] Take the cable materials of Examples 1-4 and Comparative Examples 1-3, first wind them with a 5 kg load, place them at room temperature for 1 hour, observe whether they crack, then increase the load to 7 kg, and observe whether they crack under the same test conditions. If there is no cracking, the crack resistance is good.

[0073] Tensile strength and elongation at break tests

[0074] The cable materials of Examples 1-4 and Comparative Examples 1-3 were tested using an electronic tensile testing machine KD-1 (0-1 KN). The tensile strength and elongation at break were determined according to the GB / T 1040.1-2006 standard.

[0075] Table 1: Performance test results of various embodiments and comparative examples

[0076]

[0077]

[0078] As can be seen from Table 1, no cracks appeared on the surfaces of Examples 1-4 and Comparative Examples 2-3 after the crack resistance test, so their crack resistance performance is good. The tensile strengths of Examples 1-4 and Comparative Examples 2-3 are relatively close, and are significantly higher than Comparative Example 1. Although the elongation at break of Comparative Example 1 is significantly higher than that of other samples, its low tensile strength and cracking phenomenon indicate that the toughness of the material is insufficient and it cannot effectively disperse external stress, so it is prone to cracking. The reason is that Examples 1-4 and Comparative Examples 2-3 all contain HDPE, and the molecular structures of HDPE and EVA are compatible. HDPE is a linear polymer with a high degree of crystallinity. The vinyl acetate units contained in the EVA molecular chains can interact with the molecular chains in HDPE to form a relatively tight compatible interface. At the same time, the increase in the degree of cross-linking between HDPE and EVA makes it more difficult to slip between the molecular chains, thereby improving the material's crack resistance.

[0079] Flame retardancy test

[0080] The cable materials of Examples 1-4 and Comparative Examples 1-3 were tested for oxygen index using an oxygen index meter (YG813 model) in accordance with GB / T2406.2--2009 standard.

[0081] Table 2: Flame retardant performance test results of various embodiments and comparative examples

[0082]

[0083]

[0084] The higher the oxygen index, the better the flame retardancy of the material. As can be seen from Table 2, the oxygen indexes of Examples 1-4, Comparative Example 1 and Comparative Example 3 are relatively high. The reason is that the materials of Examples 1-4, Comparative Example 1 and Comparative Example 3 contain magnesium hydroxide, which reduces the temperature of the cable matrix through the dehydration and heat absorption effect of the condensed phase, dilutes the gaseous combustibles and oxygen concentration, and thus achieves the purpose of flame retardancy and smoke suppression.

[0085] The oxygen index of Example 1 is higher than that of Comparative Example 3. The reason is that Example 1 contains more nitrogen and silicon elements. The nitrogen element will decompose and produce a large amount of non-combustible gas during combustion. The non-combustible gas can dilute the concentration of oxygen around the composite material. The silicon element can migrate to the outer surface of the material during combustion, and the Si-O bonds in its molecules will be converted into Si-C bonds. The generated white combustion residues and carbides form a covering layer on the surface of the composite material, preventing the escape of combustion volatiles and preventing oxygen from contacting the matrix material, thereby improving the flame retardant properties of the cable.

[0086] Antibacterial testing

[0087] (1) Cut the cable materials of Examples 1-4 and Comparative Examples 1-3 into 1 mm × 1 mm × 12 mm blocks, sterilize them with 0.1 MPa steam for 40-50 min, dry them, and set aside.

[0088] (2) Add 0.03 mol / L phosphate buffer (PBS) to the flask, sterilize with 0.1 MPa steam for 15-25 min, cool to room temperature, then use a pipette to take the E. coli solution and add it to the bottle. Prepare the bacterial suspension in PBS to a concentration of about 1×10 4 cfu / ml.

[0089] (3) The flask was fixed on a shaking table, heated to 30°C, shaken at 220 r / min for 2 min, and 1.0 ml was taken and diluted appropriately with PBS to 10 2 .

[0090] (4) Place the samples of Examples 1-4 and Comparative Examples 1-3 into the above flasks respectively, then heat to 30°C, shake at 220 r / min for 24 h, draw 1.0 ml and dilute to 10 with PBS. 2 , as sample liquid.

[0091] (5) 1.0 ml of the sample solution before and after shaking was taken respectively, and the plate was inoculated by the agar pouring method. The plate was placed in a 37°C constant temperature box and cultured for 24 h. The viable bacteria were counted, and the bacterial concentration in the flask before and after shaking was measured to calculate the antibacterial rate.

[0092] R(%)={(BA) / B}×100

[0093] Where: R is the antibacterial rate, %; A is the colony count of the sample after 24 hours of shaking, cfu / ml; B is the colony count of the sample before shaking, cfu / ml.

[0094] Table 3: Antibacterial test results of various embodiments and comparative examples

[0095] Before shaking (cfu / ml) After shaking (cfu / ml) Antibacterial rate (%) Example 1 <![CDATA[9.10×10 3 ]]> <![CDATA[1.0×10 1 ]]> 99.99 Example 2 <![CDATA[9.25×10 3 ]]> <![CDATA[7.0×10 2 ]]> 92.42 Example 3 <![CDATA[8.94×10 3 ]]> <![CDATA[1.5×10 3 ]]> 83.22 Example 4 <![CDATA[8.83×10 3 ]]> <![CDATA[8.0×10 2 ]]> 86.80 Comparative Example 1 <![CDATA[9.46×10 3 ]]> <![CDATA[1.29×10 4 ]]> - Comparative Example 2 <![CDATA[9.83×10 3 ]]> <![CDATA[2.0×10 1 ]]> 99.80 Comparative Example 3 <![CDATA[9.58×10 3 ]]> <![CDATA[1.43×10 4 ]]> -

[0096] As can be seen from Table 3, the antibacterial rates of Examples 1-4 and Comparative Example 2 all reached 80%, and the bacterial concentration was significantly reduced. Therefore, Examples 1-4 and Comparative Example 2 had significant antibacterial effects. The reason is that Examples 1-4 and Comparative Example 2 contain quaternary ammonium groups, which have a positive charge and can adsorb on the surface of microorganisms to form micelles and gradually penetrate into the lipid layer and protein layer of the cytoplasm, thereby changing the permeability of the cell membrane and causing the cell contents to extravasate, leading to the death of the microorganisms. At the same time, they coagulate proteins, denature enzymes and structural proteins, destroy the metabolism of microorganisms, and kill the microorganisms, thereby improving the antibacterial properties of the cable.

[0097] UV resistance testing

[0098] (1) Take the cables of Example 1-4 and Comparative Example 1-3, place them in a fluorescent 313 lamp, set a heated water reservoir in the UV2000 box, irradiate them at a temperature of 60°C for 4 hours, and then place them at 50°C for condensation for 4 hours.

[0099] (2) The cable materials of Examples 1-4 and Comparative Examples 1-3 were tested for tensile strength and elongation at break using an electronic tensile testing machine KD-1 (0-1 kN) in accordance with the GB / T 1040.1-2006 standard.

[0100] Table 4: Anti-ultraviolet aging test results of various embodiments and comparative examples

[0101]

[0102] As can be seen from Table 4, the tensile strength of Examples 1-4 and Comparative Example 1 generally decreased to a certain extent, with an average decrease of about 1.0 MPa, while the tensile strength of Comparative Examples 2-3 decreased slightly more, with an average decrease of about 2.45 MPa. It can be seen that the anti-ultraviolet performance of Examples 1-4 and Comparative Example 1 is better than that of Comparative Examples 2-3. The reason is that both Examples 1-4 and Comparative Example 1 contain azo groups, which have the characteristics of photochromism and photoinduced cis-trans isomerization, and the azo group has a significant absorption peak in the ultraviolet region (especially between 200-400 nm). The reason is that the π electrons in the azo group are easily transitioned under the irradiation of ultraviolet light, from a lower energy level to a higher energy level. This transition absorbs ultraviolet light and reduces the penetration of ultraviolet light, thereby achieving an anti-ultraviolet effect.

Claims

1. A method for preparing crack-resistant modified EVA cable material, characterized in that: The preparation method is as follows: The antibacterial modified high-density polyethylene (HDPE) and ethylene-vinyl acetate copolymer (EVA) are uniformly mixed to obtain a premix. Half of the premix is ​​added to an open mill and heated to 90-110°C. The other half of the premix, anti-ultraviolet modified magnesium hydroxide, red phosphorus, superdispersant polyvinyl pyrrolidone, and antioxidant quercetin are evenly mixed and added to an open mill. The mixture is then mixed for 8-12 minutes and stirred for 3-7 minutes. The curing agent diisopropyl peroxide (DCP) and the curing accelerator triallyl isocyanurate (TAIC) are then added and the mixture is further mixed for 3-7 minutes. Refining the rubber, placing the mixed rubber in a flat vulcanizer, heating to 160-180° C., under a pressure of 3-7 MPa, vulcanizing for 15-25 minutes, and cooling for 3-7 minutes to obtain a crack-resistant modified EVA cable material, wherein the mass ratio of EVA, antibacterial modified HDPE, modified magnesium hydroxide, hyperdispersant polyvinyl pyrrolidone, antioxidant quercetin, DCP, and TAIC is 1:0.25-0.45:1.38-1.47:0.15-0.27:0.032-0.04:0.04-0.065:0.04-0.065; The preparation method of the anti-ultraviolet modified magnesium hydroxide is as follows: SS1. Add benzotriazole to ethanol solvent, stir to dissolve, add sodium hydroxide, stir, raise the temperature to 45-65°C, add bis(2-chloroethyl)amine, stir, continue to raise the temperature to 75-85°C, react for 22-26 hours, distill under reduced pressure, wash with hot deionized water, and dry with calcium chloride to obtain intermediate 2; SS2, add intermediate 2 to ether solvent, introduce nitrogen, add 3-chloropropyltrimethoxysilane dropwise for 1-2 hours, raise the temperature to 30-40°C, react for 6-8 hours, let stand for 12-16 hours, filter, wash with anhydrous ether, and distill at low pressure to obtain benzotriazole modified silane coupling agent; SS3. Dry the magnesium hydroxide in a drying oven, raise the temperature to 100-120°C, dry for 8-12 hours, cool to room temperature, add it to deionized water, stir for 8-12 minutes, then add an ethanol solution of a benzotriazole-modified silane coupling agent, raise the temperature to 30-50°C, stir and react for 20-40 minutes. After the reaction is completed, cool to room temperature, filter, wash, dry, grind, and sieve to obtain modified magnesium hydroxide; The preparation method of the antibacterial modified HDPE is as follows: S1. Add maleic anhydride to isopropanol solution, add N,N-bis(2-aminoethyl)methylamine dropwise thereto at 15-25°C, and react for 0.5-1.5h. Then add acetic anhydride and sodium acetate, raise the temperature to 25-30°C, react for 2-3h, filter, wash with deionized water, and dry at 40-50°C to obtain intermediate 1; S2. Add benzyl chloride and intermediate 1 to N,N-dimethylformamide (DMF) solvent, then add ethyl acetate catalyst, raise the temperature to 50-70°C, stir and react for 5-7 hours, cool to room temperature, precipitate with ether, and filter to obtain quaternary ammonium salt-modified maleic anhydride; S3. Add HDPE to xylene solution, heat to 130-140°C, stir until completely dissolved, then add quaternary ammonium salt modified maleic anhydride, maleic anhydride and benzoyl peroxide (BPO) initiator, react for 2-4 hours, cool to 20-30°C, filter, wash with acetone, and dry to obtain modified maleic anhydride grafted polyethylene.

2. The method for preparing the crack-resistant modified EVA cable material according to claim 1, wherein In the step S1, the mass ratio of maleic anhydride, N,N-bis(2-aminoethyl)methylamine, acetic anhydride, and sodium acetate is 1:0.55-0.60:0.12-0.14:0.006-0.

007.

3. The preparation method of the anti-cracking modified EVA cable material according to claim 1, characterized in that, In the step S2, the mass ratio of intermediate 1, benzyl chloride, and ethyl acetate is 1:0.36-0.55:0.1-0.

2.

4. The method for preparing the crack-resistant modified EVA cable material according to claim 1, wherein In step S3, the mass ratio of HDPE, quaternary ammonium salt-modified maleic anhydride, maleic anhydride, and BPO is 1:0.02-0.1:0.02-0.1:0.005-0.

03.

5. The method for preparing the crack-resistant modified EVA cable material according to claim 1, wherein In the step SS1, the mass ratio of sodium hydroxide, bis(2-chloroethyl)amine, and benzotriazole is 0.4-0.45:0.45-0.65:

1.

6. The method for preparing the crack-resistant modified EVA cable material according to claim 1, wherein In the step SS2, the mass ratio of the intermediate 2:3-chloropropyltrimethoxysilane is 1:0.12-0.

14.

7. The method for preparing the crack-resistant modified EVA cable material according to claim 1, wherein: In step SS3, the mass ratio of magnesium hydroxide to modified silane coupling agent is 1:0.8-1.2.

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