A fire-resistant and flame-retardant cable sheath material and its preparation method

Abstract

This invention discloses a fire-retardant cable sheath material and its preparation method, relating to the technical field of sheath materials. In preparing the fire-retardant cable sheath material, the present invention involves reacting boron nitride sequentially with sodium hydroxide, 1-amino-4-[2-(triethoxysilyl)ethyl]benzene, and salicylaldehyde to obtain modified boron nitride; reacting ethylene-vinyl acetate copolymer with maleic anhydride and 1-allyl-1,1,3,3-tetramethyldisiloxane to obtain pre-modified EVA; reacting the pre-modified EVA with 4-(3-aminopropyl)-2,6-di-tert-butylphenol to obtain modified EVA; and melting and mixing the modified EVA, modified boron nitride, bio-based composite flame retardant, and chloroplatinic acid, followed by pressing to obtain the fire-retardant cable sheath material. The resin-based fire-retardant cable sheath material prepared by this invention exhibits excellent flame retardancy, anti-aging properties, and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of sheath material technology, specifically to a fire-resistant and flame-retardant cable sheath material and its preparation method. Background Technology

[0002] Wires and cables have a wide range of applications in modern society, from aerospace, industrial production and transportation to household lighting. Their use is complex and diverse, which puts forward strict performance requirements for the wires and cables used in them.

[0003] In the wire and cable industry, polyolefins have long been a common polymer matrix material used in the production of various polymer composite materials for wires and cables. Among them, ethylene-vinyl acetate copolymer (EVA) and its derivatives have become important matrix materials for the preparation of high-performance polymer composite materials for wire and cable insulation and sheathing. EVA has a low limiting oxygen index, making it prone to pyrolysis and combustion at high temperatures, potentially causing fires and endangering lives and property. Therefore, it is necessary to develop flame-retardant cable sheath materials for cables used in critical locations and equipment. Summary of the Invention

[0004] The purpose of this invention is to provide a fire-resistant and flame-retardant cable sheath material and its preparation method, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A fire-resistant and flame-retardant cable sheath material, comprising, by weight parts: 98-100 parts of modified EVA, 6-7 parts of modified boron nitride, 8-9 parts of bio-based composite flame retardant, and 1-1.2 parts of chloroplatinic acid;

[0007] The modified EVA is prepared by reacting pre-modified EVA with 4-(3-aminopropyl)-2,6-di-tert-butylphenol.

[0008] The pre-modified EVA is prepared by reacting ethylene-vinyl acetate copolymer with maleic anhydride and 1-allyl-1,1,3,3-tetramethyldisiloxane.

[0009] The modified boron nitride is prepared by reacting boron nitride sequentially with sodium hydroxide, 1-amino-4-[2-(triethoxysilyl)ethyl]benzene, and salicylaldehyde;

[0010] The bio-based composite flame retardant is prepared by reacting naringenin and diallyl phosphinochloride.

[0011] A method for preparing a fire-resistant and flame-retardant cable sheath material, the method comprising the following preparation steps:

[0012] (1) Naringenin and triethylamine were added to tetrahydrofuran at a molar ratio of 1:3 to 13-15 times the mass of naringenin. Under nitrogen protection, the mixture was stirred at 0-2℃ and 300-500r / min for 8-10 min. Dipropenylphosphine chloride was added at a uniform rate within 20 min at a molar ratio of 3 times that of naringenin. The temperature was raised to 60-62℃ and the reaction was continued to be stirred for 6-7 h. The mixture was cooled to room temperature, filtered, and the filtrate was dried at 50-60℃ under vacuum for 12-14 h to obtain a bio-based composite flame retardant.

[0013] (2) Mix pre-modified boron nitride, salicylaldehyde and anhydrous ethanol in a mass ratio of 1:(5~6):(24~26) until homogeneous. Stir the mixture at 50~60℃ and 300~500r / min for 6~7h. Filter the mixture, wash it three times with anhydrous ethanol, and dry it under vacuum at 50~60℃ for 13~15h to obtain modified boron nitride.

[0014] (3) Mix pre-modified EVA, 4-(3-aminopropyl)-2,6-di-tert-butylphenol and toluene in a mass ratio of 1:(3~4):(20~24) until homogeneous. Stir at 60~64℃ and 50~60r / min for 100~120min. Add 0.01~0.03 times the mass of pre-modified EVA of triethylamine, 0.004~0.006 times the mass of pre-modified EVA of nickel acetate, and 0.04~0.06 times the mass of pre-modified EVA of acetic anhydride. Heat to 76~80℃ and continue stirring for 2~3h. Cool to room temperature and add 5~7 times the volume of toluene of methanol. Filter and dry under vacuum at 50~60℃ for 20~24h to obtain modified EVA.

[0015] (4) Weigh 98-100 parts of modified EVA, 6-7 parts of modified boron nitride, 8-9 parts of bio-based composite flame retardant, and 1-1.2 parts of chloroplatinic acid by mass. Mix the modified EVA, modified boron nitride, bio-based composite flame retardant, and chloroplatinic acid, place them in a two-roll mill, melt-blend at 120-130℃ and 70-80r / min for 13-15min, then place them on a flat vulcanizing machine, hot-press at 110-120℃ and 10MPa for 8-10min, cool to 60-70℃, stand for 2-3h, and cool naturally to room temperature to obtain fire-resistant and flame-retardant cable sheath material.

[0016] Furthermore, the reaction process of the bio-based composite flame retardant in step (1) is as follows:

[0017] .

[0018] Furthermore, the CAS number of the dielenephosphinic acid chloride mentioned in step (1) is 17620-21-2; its structural formula is... .

[0019] Further, the preparation method of the pre-modified boron nitride in step (2) is as follows: Boron nitride and 5 mol / L sodium hydroxide aqueous solution are mixed evenly at a mass ratio of 1:20~30, stirred and reacted at 100~110℃ for 8~10h, filtered, and vacuum dried at 70~80℃ for 20~24h to obtain activated boron nitride; activated boron nitride, anhydrous ethanol, and deionized water are mixed at a mass ratio of 1:(30~36):(20~24), ultrasonically dispersed for 1~2h, 1-amino-4-[2-(triethoxysilyl)ethyl]benzene with a mass of 4~5 times that of activated boron nitride is added, the temperature is raised to 60~70℃, stirred and reacted at 300~500r / min for 8~10h, filtered, washed 3 times each with anhydrous ethanol and deionized water, and dried at 50~60℃ for 13~15h under vacuum to obtain pre-modified boron nitride.

[0020] Furthermore, the CAS number of the 1-amino-4-[2-(triethoxysilyl)ethyl]benzene is 18418-80-9; its structural formula is as follows: .

[0021] Furthermore, the boron nitride has a particle size of 1500 mesh.

[0022] Further, the preparation method of the pre-modified EVA in step (3) is as follows: maleic anhydride, 1-allyl-1,1,3,3-tetramethyldisiloxane, diisopropyl peroxide, and acetone are mixed evenly in a mass ratio of 1:(0.6~0.8):(0.03~0.05):(10~12), stirred at 300~400r / min for 10~20min at 40~50℃, ethylene-vinyl acetate copolymer with a mass of 20~22 times that of maleic anhydride is added, and stirring is continued for 25~35min. The mixture is then allowed to stand for 16~18h to obtain the EVA premix. The EVA premix is ​​then placed in a rheometer for melt plasticization to obtain the pre-modified EVA.

[0023] Furthermore, the process parameters for the melt plasticizing are: plasticizing temperature of 150~160℃, time of 9~10min, and rotation speed of 50~60r / min.

[0024] Furthermore, the VA content of the ethylene-vinyl acetate copolymer is 28%, and it was purchased from DuPont, USA.

[0025] The beneficial effects achieved by this invention are as follows:

[0026] First, a bio-based composite flame retardant is prepared by reacting naringenin and diallyl phosphine chloride. Naringenin is a natural flavonoid compound whose structure promotes char formation. By combining naringenin with phosphorus for synergistic flame retardancy, the flame retardant performance of fireproof and flame-retardant cable sheath materials is significantly improved.

[0027] Second, boron nitride is activated with sodium hydroxide; pre-modified boron nitride is prepared by reacting activated boron nitride with 1-amino-4-[2-(triethoxysilyl)ethyl]benzene, and aniline groups are introduced onto the pre-modified boron nitride; the aniline groups on the pre-modified boron nitride undergo a Schiff base reaction with the aldehyde groups on salicylaldehyde to obtain modified boron nitride; a Schiff base structure is generated on the modified boron nitride, and the C=N bond in the Schiff base structure can undergo isomerization after being given appropriate energy, which significantly improves the ultraviolet absorption capacity, thereby improving the anti-aging performance of the fireproof and flame-retardant cable sheath material.

[0028] Third, pre-modified EVA was prepared by grafting maleic anhydride and 1-allyl-1,1,3,3-tetramethyldisiloxane onto the side chains of ethylene-vinyl acetate copolymer molecules via melt grafting. Modified EVA was then prepared by reacting the anhydride on the pre-modified EVA with the amino group on 4-(3-aminopropyl)-2,6-di-tert-butylphenol. Hindered phenolic antioxidants were grafted onto the side chains of the modified EVA molecules to further improve the anti-aging performance of the fire-retardant cable sheath material. Furthermore, grafting 1-allyl-1,1,3,3-tetramethyldisiloxane onto the side chains of EVA molecules introduced siloxane structures and Si-H bonds. The siloxane structure can form a dense carbon layer during combustion, isolating heat sources and oxygen, thus improving flame retardant performance. The Si-H bonds can undergo hydrosilylation with the C=C bonds on the bio-based composite flame retardant to form a cross-linked network structure, thereby improving the mechanical properties of the fire-retardant cable sheath material. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1: A method for preparing a fire-resistant and flame-retardant cable sheath material, the method comprising the following preparation steps:

[0031] (1) Naringenin and triethylamine were added to tetrahydrofuran at a molar ratio of 1:3 to 13 times the mass of naringenin. Under nitrogen protection, the mixture was stirred at 0°C for 10 min. Dipropenylphosphine chloride was added at a uniform rate at a molar ratio of 3 times that of naringenin within 20 min. The temperature was raised to 60°C and the reaction was continued to be stirred for 7 h. The mixture was cooled to room temperature, filtered, and the filtrate was dried at 50°C for 14 h under vacuum to obtain a bio-based composite flame retardant.

[0032] (2) Boron nitride and 5 mol / L sodium hydroxide aqueous solution were mixed evenly at a mass ratio of 1:20, stirred at 100℃ for 10 h, filtered, and dried under vacuum at 70℃ for 24 h to obtain activated boron nitride; activated boron nitride, anhydrous ethanol and deionized water were mixed at a mass ratio of 1:30:20, ultrasonically dispersed for 1 h, 1-amino-4-[2-(triethoxysilyl)ethyl]benzene with a mass of 4 times that of activated boron nitride was added, the temperature was raised to 60℃, stirred for 10 h, filtered, washed 3 times each with anhydrous ethanol and deionized water, and dried under vacuum at 50℃ for 15 h to obtain pre-modified boron nitride; pre-modified boron nitride, salicylaldehyde and anhydrous ethanol were mixed evenly at a mass ratio of 1:5:24, stirred at 50℃ for 7 h, filtered, washed 3 times with anhydrous ethanol, and dried under vacuum at 50℃ for 15 h to obtain modified boron nitride;

[0033] (3) Maleic anhydride, 1-allyl-1,1,3,3-tetramethyldisiloxane, diisopropyl peroxide, and acetone were mixed evenly in a mass ratio of 1:0.6:0.03:10. The mixture was stirred at 40°C for 20 min. 20 times the mass of maleic anhydride was added to the ethylene-vinyl acetate copolymer, and the mixture was stirred for another 35 min. The mixture was then allowed to stand for 16 h to obtain an EVA premix. The EVA premix was placed in a rheometer for melt plasticization. The melt plasticization temperature was set at 150°C, the time was 10 min, and the rotation speed was 50 r / min to obtain pre-modified EVA. The pre-modified EVA was then... Premodified EVA, 4-(3-aminopropyl)-2,6-di-tert-butylphenol, and toluene were mixed evenly in a mass ratio of 1:3:20. The mixture was stirred at 60℃ and 50 r / min for 120 min. Triethylamine (0.01 times the mass of premodified EVA), nickel acetate (0.004 times the mass of premodified EVA), and acetic anhydride (0.04 times the mass of premodified EVA) were added. The mixture was heated to 76℃ and stirred for another 3 h. After cooling to room temperature, methanol (5 times the volume of toluene) was added and mixed. The mixture was filtered and dried at 50℃ under vacuum for 24 h to obtain modified EVA.

[0034] (4) Weigh 98 parts of modified EVA, 6 parts of modified boron nitride, 8 parts of bio-based composite flame retardant, and 1 part of chloroplatinic acid by mass. Mix the modified EVA, modified boron nitride, bio-based composite flame retardant, and chloroplatinic acid, place them in a two-roll mill, melt-blend at 120°C for 15 min, then place them on a flat vulcanizing machine, hot-press at 110°C and 10 MPa for 10 min, cool down to 60°C, stand for 3 h, and naturally cool to room temperature to obtain fire-resistant and flame-retardant cable sheath material.

[0035] Example 2: A method for preparing a fire-resistant and flame-retardant cable sheath material, the method comprising the following preparation steps:

[0036] (1) Naringenin and triethylamine were added to tetrahydrofuran at a molar ratio of 1:3 to 14 times the mass of naringenin. Under nitrogen protection, the mixture was stirred at 1°C for 9 min. Dipropenylphosphine chloride was added at a uniform rate at a molar ratio of 3 times that of naringenin within 20 min. The temperature was raised to 61°C and the reaction was stirred for 6.5 h. The mixture was cooled to room temperature, filtered, and the filtrate was dried at 55°C for 13 h under vacuum to obtain a bio-based composite flame retardant.

[0037] (2) Boron nitride and 5 mol / L sodium hydroxide aqueous solution were mixed evenly at a mass ratio of 1:25, stirred at 105℃ for 9 h, filtered, and dried under vacuum at 75℃ for 22 h to obtain activated boron nitride; activated boron nitride, anhydrous ethanol, and deionized water were mixed at a mass ratio of 1:33:22, ultrasonically dispersed for 1.5 h, 1-amino-4-[2-(triethoxysilyl)ethyl]benzene with a mass of 4.5 times that of activated boron nitride was added, heated to 65℃, stirred for 9 h, filtered, washed 3 times each with anhydrous ethanol and deionized water, and dried under vacuum at 55℃ for 14 h to obtain pre-modified boron nitride; pre-modified boron nitride, salicylaldehyde, and anhydrous ethanol were mixed evenly at a mass ratio of 1:5.5:25, stirred at 55℃ for 6.5 h, filtered, washed 3 times with anhydrous ethanol, and dried under vacuum at 55℃ for 14 h to obtain modified boron nitride;

[0038] (3) Maleic anhydride, 1-allyl-1,1,3,3-tetramethyldisiloxane, diisopropyl peroxide, and acetone were mixed evenly in a mass ratio of 1:0.7:0.04:11. The mixture was stirred at 45°C for 15 min, and ethylene-vinyl acetate copolymer (21 times the mass of maleic anhydride) was added. The mixture was stirred for another 30 min and allowed to stand for 17 h to obtain an EVA premix. The EVA premix was then melt-plasticized in a rheometer at a temperature of 155°C for 9.5 min and a rotation speed of 55 r / min to obtain pre-modified EVA. EVA, 4-(3-aminopropyl)-2,6-di-tert-butylphenol, and toluene were mixed evenly in a mass ratio of 1:3.5:22. The mixture was stirred at 62℃ and 55 r / min for 110 min. Triethylamine (0.02 times the mass of pre-modified EVA), nickel acetate (0.005 times the mass of pre-modified EVA), and acetic anhydride (0.05 times the mass of pre-modified EVA) were added. The mixture was heated to 78℃ and stirred for another 2.5 h. After cooling to room temperature, methanol (6 times the volume of toluene) was added and mixed. The mixture was filtered and dried at 55℃ under vacuum for 22 h to obtain modified EVA.

[0039] (4) Weigh 99 parts of modified EVA, 6.5 parts of modified boron nitride, 8.5 parts of bio-based composite flame retardant, and 1.1 parts of chloroplatinic acid by mass. Mix the modified EVA, modified boron nitride, bio-based composite flame retardant, and chloroplatinic acid, place them in a two-roll mill, melt-blend at 125°C for 14 min, then place them on a flat vulcanizing machine, hot-press at 115°C and 10MPa for 9 min, cool down to 65°C, let stand for 2.5 h, and naturally cool to room temperature to obtain fire-resistant and flame-retardant cable sheath material.

[0040] Example 3: A method for preparing a fire-resistant and flame-retardant cable sheath material, the method comprising the following preparation steps:

[0041] (1) Naringenin and triethylamine were added to tetrahydrofuran at a molar ratio of 1:3 to 15 times the mass of naringenin. Under nitrogen protection, the mixture was stirred at 2°C for 8 min. Dipropenylphosphine chloride was added at a uniform rate at a molar ratio of 3 times that of naringenin within 20 min. The temperature was raised to 62°C and the reaction was stirred for 6 h. The mixture was cooled to room temperature, filtered, and the filtrate was dried at 60°C for 12 h under vacuum to obtain a bio-based composite flame retardant.

[0042] (2) Boron nitride and 5 mol / L sodium hydroxide aqueous solution were mixed evenly at a mass ratio of 1:30, stirred at 110℃ for 8 h, filtered, and dried under vacuum at 80℃ for 20 h to obtain activated boron nitride; activated boron nitride, anhydrous ethanol, and deionized water were mixed at a mass ratio of 1:36:24, ultrasonically dispersed for 2 h, 1-amino-4-[2-(triethoxysilyl)ethyl]benzene with a mass of 5 times that of activated boron nitride was added, the temperature was raised to 70℃, stirred for 8 h, filtered, washed 3 times each with anhydrous ethanol and deionized water, and dried under vacuum at 60℃ for 13 h to obtain pre-modified boron nitride; pre-modified boron nitride, salicylaldehyde, and anhydrous ethanol were mixed evenly at a mass ratio of 1:6:26, stirred at 60℃ for 6 h, filtered, washed 3 times with anhydrous ethanol, and dried under vacuum at 60℃ for 13 h to obtain modified boron nitride;

[0043] (3) Maleic anhydride, 1-allyl-1,1,3,3-tetramethyldisiloxane, diisopropyl peroxide, and acetone were mixed evenly in a mass ratio of 1:0.8:0.05:12. The mixture was stirred at 50°C for 10 min, and ethylene-vinyl acetate copolymer (22 times the mass of maleic anhydride) was added. The mixture was stirred for another 25 min and allowed to stand for 18 h to obtain an EVA premix. The EVA premix was then melt-plasticized in a rheometer at a temperature of 160°C for 9 min and a rotation speed of 60 r / min to obtain pre-modified EVA. Premodified EVA, 4-(3-aminopropyl)-2,6-di-tert-butylphenol, and toluene were mixed evenly in a mass ratio of 1:4:24. The mixture was stirred at 64℃ and 60 r / min for 100 min. Triethylamine (0.03 times the mass of premodified EVA), nickel acetate (0.006 times the mass of premodified EVA), and acetic anhydride (0.06 times the mass of premodified EVA) were added. The mixture was heated to 80℃ and stirred for 2 h. After cooling to room temperature, methanol (7 times the volume of toluene) was added and mixed. The mixture was filtered and dried at 60℃ under vacuum for 20 h to obtain modified EVA.

[0044] (4) Weigh 100 parts of modified EVA, 7 parts of modified boron nitride, 9 parts of bio-based composite flame retardant, and 1.2 parts of chloroplatinic acid by mass. Mix the modified EVA, modified boron nitride, bio-based composite flame retardant, and chloroplatinic acid, place them in a two-roll mill, melt-blend at 130°C for 13 min, then place them on a flat vulcanizing machine, hot-press at 120°C and 10MPa for 8 min, cool down to 70°C, let stand for 2 h, and naturally cool to room temperature to obtain fire-resistant and flame-retardant cable sheath material.

[0045] Comparative Example 1:

[0046] The difference between the preparation method of the fire-retardant cable sheath material in Comparative Example 1 and Example 2 is that step (1) is omitted, and step (4) is modified as follows: 99 parts of modified EVA, 6.5 parts of modified boron nitride, and 1.1 parts of chloroplatinic acid are weighed by mass; the modified EVA, modified boron nitride, and chloroplatinic acid are mixed and placed in a two-roll mill, melt-blended at 125°C for 14 min, then placed on a flat vulcanizing machine, hot-pressed at 115°C and 10 MPa for 9 min, cooled to 65°C, left to stand for 2.5 h, and naturally cooled to room temperature to obtain the fire-retardant cable sheath material. The remaining steps are the same as in Example 2.

[0047] Comparative Example 2:

[0048] The preparation method of the fire-retardant cable sheath material in Comparative Example 2 differs from that in Example 2 in that step (2) is omitted, and step (4) is modified as follows: 99 parts of modified EVA, 6.5 parts of boron nitride, 8.5 parts of bio-based composite flame retardant, and 1.1 parts of chloroplatinic acid are weighed by mass. The modified EVA, boron nitride, bio-based composite flame retardant, and chloroplatinic acid are mixed and placed in a two-roll mill. The mixture is melt-blended at 125°C for 14 minutes, then placed on a flat vulcanizing machine and hot-pressed at 115°C and 10MPa for 9 minutes. The mixture is then cooled to 65°C, allowed to stand for 2.5 hours, and allowed to cool naturally to room temperature to obtain the fire-retardant cable sheath material. The remaining steps are the same as in Example 2.

[0049] Comparative Example 3:

[0050] The preparation method of the fire-retardant cable sheath material in Comparative Example 3 differs from that in Example 2 only in step (3). Step (3) is modified as follows: maleic anhydride, 1-allyl-1,1,3,3-tetramethyldisiloxane, diisopropyl peroxide, and acetone are mixed evenly in a mass ratio of 1:0.7:0.04:11, stirred at 45°C for 15 min, and ethylene-vinyl acetate copolymer with a mass ratio of 21 times that of maleic anhydride is added. The mixture is stirred for another 30 min and allowed to stand for 17 h to obtain an EVA premix. The EVA premix is ​​then placed in a rheometer for melt plasticization. The melt plasticization temperature is set at 155°C, the time is 9.5 min, and the rotation speed is 55 r / min to obtain modified EVA. The remaining steps are the same as in Example 2.

[0051] Comparative Example 4:

[0052] The difference between the preparation method of the fire-retardant cable sheath material in Comparative Example 4 and Example 2 lies only in step (3). Step (3) is modified as follows: maleic anhydride, diisopropyl peroxide, and acetone are mixed evenly at a mass ratio of 1:0.04:11, stirred at 45°C for 15 min, and ethylene-vinyl acetate copolymer with a mass of 21 times that of maleic anhydride is added. The mixture is stirred for another 30 min and allowed to stand for 17 h to obtain EVA premix. The EVA premix is ​​then placed in a rheometer for melt plasticization. The melt plasticization temperature is set at 155°C, the time is 9.5 min, and the rotation speed is 55 r / min to obtain the premix. Modified EVA: Pre-modified EVA, 4-(3-aminopropyl)-2,6-di-tert-butylphenol, and toluene were mixed uniformly at a mass ratio of 1:3.5:22. The mixture was stirred at 62°C and 55 rpm for 110 min. Triethylamine (0.02 times the mass of pre-modified EVA), nickel acetate (0.005 times the mass of pre-modified EVA), and acetic anhydride (0.05 times the mass of pre-modified EVA) were added. The mixture was heated to 78°C and stirred for another 2.5 h. After cooling to room temperature, methanol (6 times the volume of toluene) was added and mixed. The mixture was filtered and dried under vacuum at 55°C for 22 h to obtain modified EVA. The remaining steps were the same as in Example 2.

[0053] Test Example 1

[0054] Flame retardant performance testing

[0055] Test method: The limiting oxygen index of the test examples and comparative examples was tested according to GB / T 2406.2—2009. The sample size was 150 mm × 6.5 mm × 3 mm. The results are shown in Table 1.

[0056] Table 1

[0057]

[0058] The limiting oxygen index of Example 2 is greater than that of Comparative Example 1. This is because a bio-based composite flame retardant is prepared by reacting naringenin and diallyl phosphine chloride. Naringenin is a natural flavonoid compound containing a deoxybenzoic acid ester structure, which can promote char formation. The synergistic flame retardancy of naringenin and phosphorus significantly improves the flame retardant performance of the fireproof and flame-retardant cable sheath material.

[0059] The limiting oxygen index of Example 2 is greater than that of Comparative Example 4. This is because maleic anhydride and 1-allyl-1,1,3,3-tetramethyldisiloxane were grafted onto the side chains of the ethylene-vinyl acetate copolymer molecules by melt grafting to obtain pre-modified EVA. By grafting 1-allyl-1,1,3,3-tetramethyldisiloxane onto the side chains of EVA molecules, a siloxane structure is introduced onto the side chains of EVA molecules. The siloxane structure can form a dense carbon layer during combustion, which isolates the heat source and oxygen, thereby improving the flame retardant performance.

[0060] Test Example 2

[0061] Testing of mechanical properties and anti-aging properties

[0062] Test method: GB / T 1040 specifies that standard specimens are prepared from the examples and comparative examples, and the tensile strength F of the standard specimens is tested under the following conditions: 25℃, 200 mm / min. The standard specimens are then placed in an ultraviolet aging chamber for accelerated aging tests, with an irradiation intensity of 50 W / m. 2 The temperature was 60℃ and the time was 18 days. After the artificial accelerated aging test, the tensile strength N of the standard specimen was tested, and the performance degradation rate of the standard specimen after aging was calculated; performance degradation rate = (FN) / F×100%. The results are shown in Table 2.

[0063] Table 2

[0064]

[0065] The tensile strength of Example 2 is greater than that of Comparative Example 1. This is because the bio-based composite flame retardant is prepared by reacting naringenin and diallyl phosphinochloride. The carbon-carbon double bond introduced on the bio-based composite flame retardant can undergo a hydrosilylation reaction with the Si-H bond introduced on the side chain of the modified EVA molecule to form a cross-linked network structure, thereby improving the mechanical properties of the fireproof and flame-retardant cable sheath material.

[0066] The tensile strength of Example 2 is greater than that of Comparative Example 4. This is because maleic anhydride and 1-allyl-1,1,3,3-tetramethyldisiloxane are grafted onto the side chains of the ethylene-vinyl acetate copolymer molecules via melt grafting to obtain pre-modified EVA. By grafting 1-allyl-1,1,3,3-tetramethyldisiloxane onto the side chains of EVA molecules, Si-H bonds are introduced onto the side chains of EVA molecules. These Si-H bonds can undergo hydrosilylation reactions with the carbon-carbon double bonds on the modified boron nitride and bio-based composite flame retardant to form a cross-linked network structure, thereby improving the mechanical properties of the fire-retardant cable sheath material.

[0067] The performance degradation rate of Example 2 is less than that of Comparative Example 2. This is because pre-modified boron nitride is prepared by reacting activated boron nitride with 1-amino-4-[2-(triethoxysilyl)ethyl]benzene, and aniline groups are introduced onto the pre-modified boron nitride. The aniline groups on the pre-modified boron nitride undergo a Schiff base reaction with the aldehyde groups on salicylaldehyde to obtain modified boron nitride. A Schiff base structure is generated on the modified boron nitride. The C=N bonds in the Schiff base structure can undergo isomerization after being given appropriate energy, which significantly improves the ultraviolet absorption capacity, thereby improving the anti-aging performance of the fireproof and flame-retardant cable sheath material.

[0068] The performance degradation rate of Example 2 was less than that of Comparative Example 3. This is because maleic anhydride and 1-allyl-1,1,3,3-tetramethyldisiloxane were grafted onto the side chains of the ethylene-vinyl acetate copolymer molecule by melt grafting to obtain pre-modified EVA. The anhydride on the pre-modified EVA was reacted with the amino group on 4-(3-aminopropyl)-2,6-di-tert-butylphenol to obtain modified EVA. A hindered phenolic antioxidant was grafted onto the side chains of the modified EVA molecule to further improve the anti-aging performance of the fire-retardant cable sheath material.

[0069] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fire-resistant and flame-retardant cable sheath material, characterized in that, By weight, it includes: 98-100 parts of modified EVA, 6-7 parts of modified boron nitride, 8-9 parts of bio-based composite flame retardant, and 1-1.2 parts of chloroplatinic acid; The modified EVA is prepared as follows: pre-modified EVA, 4-(3-aminopropyl)-2,6-di-tert-butylphenol, and toluene are mixed evenly in a mass ratio of 1:(3~4):(20~24), and stirred at 60~64℃ for 100~120 min. Then, 0.01~0.03 times the mass of pre-modified EVA, 0.004~0.006 times the mass of pre-modified EVA, and 0.04~0.06 times the mass of pre-modified EVA, are added. The temperature is raised to 76~80℃, and the stirring reaction is continued for 2~3 h. The mixture is cooled to room temperature, and 5~7 times the volume of methanol is added to the mixture. The mixture is filtered and dried to obtain the modified EVA. The preparation method of the pre-modified EVA is as follows: maleic anhydride, 1-allyl-1,1,3,3-tetramethyldisiloxane, diisopropyl peroxide, and acetone are mixed evenly in a mass ratio of 1:(0.6~0.8):(0.03~0.05):(10~12), stirred at 40~50℃ for 10~20 min, ethylene-vinyl acetate copolymer with a mass of 20~22 times that of maleic anhydride is added, stirring is continued for 25~35 min, and the mixture is allowed to stand for 16~18 h to obtain EVA premix; the EVA premix is ​​placed in a rheometer for melt plasticization to obtain pre-modified EVA; The modified boron nitride is prepared by mixing pre-modified boron nitride, salicylaldehyde, and anhydrous ethanol in a mass ratio of 1:(5~6):(24~26), reacting at 50~60℃ for 6~7h, filtering, washing, and drying to obtain modified boron nitride. The preparation method of the pre-modified boron nitride is as follows: Boron nitride and 5 mol / L sodium hydroxide aqueous solution are mixed evenly at a mass ratio of 1:20~30, stirred and reacted at 100~110℃ for 8~10h, filtered, and dried to obtain activated boron nitride; activated boron nitride, anhydrous ethanol, and deionized water are mixed at a mass ratio of 1:(30~36):(20~24), ultrasonically dispersed for 1~2h, 1-amino-4-[2-(triethoxysilyl)ethyl]benzene with a mass of 4~5 times that of activated boron nitride is added, the temperature is raised to 60~70℃ and stirred and reacted for 8~10h, filtered, washed, and dried to obtain pre-modified boron nitride; The preparation method of the bio-based composite flame retardant is as follows: Naringenin and triethylamine are added to tetrahydrofuran at a molar ratio of 1:3 to 13-15 times the mass of naringenin. Under nitrogen protection, the mixture is stirred at 0-2°C for 8-10 min. Dipropenylphosphine chloride, at a molar ratio of 3 times that of naringenin, is added uniformly over 20 min. The temperature is raised to 60-62°C, and the reaction is continued with stirring for 6-7 h. The mixture is then cooled to room temperature, filtered, and the filtrate is collected under vacuum to obtain the bio-based composite flame retardant.

2. A method for preparing a fire-resistant and flame-retardant cable sheath material, characterized in that, The preparation method of the fire-resistant and flame-retardant cable sheath material includes the following preparation steps: (1) Add naringenin and triethylamine to tetrahydrofuran, stir at 0~2℃ for 8~10 min under nitrogen protection, add diallylphosphine chloride at a uniform rate within 20 min, raise the temperature to 60~62℃, continue stirring for 6~7 h, cool to room temperature, filter, and vacuum dry the filtrate to obtain bio-based composite flame retardant. The molar ratio of naringenin, triethylamine, and diallylphosphine chloride is 1:3:3; (2) Mix pre-modified boron nitride, salicylaldehyde and anhydrous ethanol in a mass ratio of 1:(5~6):(24~26) until homogeneous, stir and react at 50~60℃ for 6~7h, filter, wash and dry to obtain modified boron nitride. The preparation method of the pre-modified boron nitride is as follows: Boron nitride and 5 mol / L sodium hydroxide aqueous solution are mixed evenly at a mass ratio of 1:20~30, stirred and reacted at 100~110℃ for 8~10h, filtered, and dried to obtain activated boron nitride; activated boron nitride, anhydrous ethanol, and deionized water are mixed at a mass ratio of 1:(30~36):(20~24), ultrasonically dispersed for 1~2h, 1-amino-4-[2-(triethoxysilyl)ethyl]benzene with a mass of 4~5 times that of activated boron nitride is added, the temperature is raised to 60~70℃ and stirred and reacted for 8~10h, filtered, washed, and dried to obtain pre-modified boron nitride; (3) Mix pre-modified EVA, 4-(3-aminopropyl)-2,6-di-tert-butylphenol and toluene in a mass ratio of 1:(3~4):(20~24) until homogeneous. React at 60~64℃ for 100~120 min. Add 0.01~0.03 times the mass of pre-modified EVA triethylamine, 0.004~0.006 times the mass of pre-modified EVA nickel acetate, and 0.04~0.06 times the mass of pre-modified EVA acetic anhydride. Heat to 76~80℃ and continue stirring for 2~3 h. Cool to room temperature and add 5~7 times the volume of toluene methanol. Filter and dry to obtain modified EVA. The preparation method of the pre-modified EVA is as follows: maleic anhydride, 1-allyl-1,1,3,3-tetramethyldisiloxane, diisopropyl peroxide, and acetone are mixed evenly in a mass ratio of 1:(0.6~0.8):(0.03~0.05):(10~12), stirred at 40~50℃ for 10~20 min, ethylene-vinyl acetate copolymer with a mass of 20~22 times that of maleic anhydride is added, stirring is continued for 25~35 min, and the mixture is allowed to stand for 16~18 h to obtain EVA premix; the EVA premix is ​​placed in a rheometer for melt plasticization to obtain pre-modified EVA; (4) Mix modified EVA, modified boron nitride, bio-based composite flame retardant and chloroplatinic acid, place them in a two-roll mill, melt-blend at 120~130℃ for 13~15min, then place them on a flat vulcanizing machine, hot press at 110~120℃ and 10MPa for 8~10min, cool down to 60~70℃, let stand for 2~3h, and naturally cool to room temperature to obtain fireproof and flame-retardant cable sheath material.

3. The method for preparing a fire-resistant and flame-retardant cable sheath material as described in claim 2, characterized in that, The boron nitride in step (2) has a particle size of 1500 mesh.

4. The method for preparing a fire-resistant and flame-retardant cable sheath material as described in claim 2, characterized in that, The process parameters for melting and plasticizing in step (3) are: plasticizing temperature of 150~160℃, time of 9~10min, and rotation speed of 50~60r / min.

5. The method for preparing a fire-resistant and flame-retardant cable sheath material as described in claim 2, characterized in that, The amounts of modified EVA, modified boron nitride, bio-based composite flame retardant, and chloroplatinic acid in step (4) are as follows: by mass parts, 98-100 parts of modified EVA, 6-7 parts of modified boron nitride, 8-9 parts of bio-based composite flame retardant, and 1-1.2 parts of chloroplatinic acid.

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