A high-strength, high-toughness, low-smoke, halogen-free, flame-retardant, and rodent-proof cable sheath material and its preparation method

Abstract

This invention proposes a high-strength, high-toughness, low-smoke, halogen-free, flame-retardant, and rodent-proof cable sheath material and its preparation method. The raw materials for this cable sheath material include 80.0–100.0 parts of a polymer matrix, 80.0–100.0 parts of an inorganic flame retardant, a functional biomass rodent repellent, 2.0–4.0 parts of a vulcanizing agent, and 0.5–1.0 parts of a vulcanization accelerator. The functional biomass rodent repellent is prepared by a one-pot method using bio-based diol, bio-based diisocyanate, and capsaicin. The cable sheath material is obtained by adding the raw materials in proportion to an extruder for melting, blending, and extrusion, followed by cooling, curing, traction, pelletizing, and drying. The cable sheath material obtained by this invention possesses high strength, high toughness, high flame retardancy, and long-lasting rodent-proof properties, meeting the needs of the cable industry for materials with high mechanical properties, flame retardant performance, and long-lasting rodent-proof properties.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology and science, specifically relating to a high-strength, high-toughness, low-smoke, halogen-free, flame-retardant, and rodent-proof cable sheath material and its preparation method. Background Technology

[0002] The cable sheath is the outermost layer of a cable. As the most important barrier protecting the internal structure of the cable, it is related not only to the safety of cable laying and use, but also to the actual service life of the cable. With the ever-increasing demand for electricity in modern society, the safety, reliability, and durability of cables, as an important carrier of power transmission, have become particularly important.

[0003] However, during use, cables are not only affected by environmental factors such as oxygen, heat, light, force, and chemical corrosion, but also by the erosion of organisms such as termites and rodents. This can lead to power outages and signal failures, and may even cause safety accidents such as fires. Furthermore, cables often produce large amounts of smoke and harmful gases during combustion, causing environmental pollution and significant harm to human health. This necessitates that cable sheath materials, while meeting basic manufacturing performance requirements, possess characteristics such as high strength and toughness, low smoke, halogen-free flame retardancy, and rodent resistance. Traditional cable sheath materials are insufficient to meet the diverse needs of the market.

[0004] To address these issues, researchers have introduced inorganic flame retardants to improve the halogen-free flame retardant properties of materials. However, their flame retardant efficiency is low, often requiring high filler content to achieve the desired effect. Simultaneously, their high surface energy and strong hydrophilicity result in poor compatibility with the non-polar polymer matrices commonly used in cable materials, leading to a decline in the mechanical properties of the composite material. To prevent bio-erosion, researchers have used rodent repellents or physical methods to form armor structures to enhance rodent resistance. However, these methods are prone to high costs, unstable service life, and environmental impact. Currently, natural plant extracts such as capsaicin are commonly used, achieving good rodent repellency through stimulation of rats' sense of smell, taste, and nerves. However, capsaicin has poor thermal stability and is prone to small molecule migration. During wire and cable processing and installation, it easily sublimates and migrates to the material surface, significantly reducing the service life and stability of the cable material, failing to meet the application requirements in complex environments.

[0005] Therefore, developing a new type of cable sheath material that can achieve high strength, high toughness, low smoke, halogen-free flame retardancy, and rodent-proof properties is of great significance to the development of the cable industry. Summary of the Invention

[0006] Based on the problems existing in the prior art, the purpose of this invention is to provide a cable sheath material and its preparation method, which, through the synergistic effect of functional biomass rodent repellent and other materials, endows the material with characteristics such as high strength, high toughness, low smoke, halogen-free flame retardancy, and rodent repellency.

[0007] To achieve its objectives, the present invention employs the following technical solution:

[0008] A high-strength, high-toughness, low-smoke, halogen-free, flame-retardant, and rodent-proof cable sheath material, characterized in that the raw materials, by weight, comprise:

[0009]

[0010]

[0011] The functional biomass rodenticide is a polyurethane prepolymer containing a capsaicin-terminated structure, and its general structural formula is:

[0012]

[0013] R1 is a structural unit in bio-based diisocyanate, and R2 is a structural unit in bio-based diol.

[0014] In some embodiments of the present invention, the preparation method of the functional biomass rodenticide includes the following steps:

[0015] (1) Add bio-based diol to the reactor and stir under vacuum at 100-105°C for 0.5-1.0 h to remove the water contained in the bio-based diol.

[0016] (2) Cool the dehydrated bio-based diol from step (1) to 75–80°C, add bio-based diisocyanate and catalyst, raise the temperature to 85–95°C, and mechanically stir the reaction for 3–4 hours; then add capsaicin and solvent, and continue the reaction at 85–95°C for 3–5 hours. After the reaction is complete, degas under vacuum at room temperature to obtain the functional biomass rodenticide. The molar ratio of the bio-based diol, the bio-based diisocyanate, and capsaicin is 1:2–3:2–4.

[0017] In some embodiments of the present invention, the polymer matrix is ​​one or more of polyethylene, polypropylene, ethylene-vinyl acetate copolymer and polyvinyl chloride, wherein the tensile strength of the polymer matrix is ​​5 to 30 MPa and the elongation at break is 150 to 800%.

[0018] In some embodiments of the present invention, the inorganic flame retardant is one or more of magnesium hydroxide, aluminum hydroxide and ammonium polyphosphate.

[0019] In some embodiments of the present invention, the vulcanizing agent is one or more of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, benzoyl peroxide, di-tert-butyl peroxide, and dicumyl peroxide.

[0020] In some embodiments of the present invention, the vulcanization accelerator is one or more of metal oxides, triallyl cyanurate and trimethylolpropane triacrylate.

[0021] This invention also proposes a method for preparing the high-strength, high-toughness, low-smoke, halogen-free, flame-retardant, and rodent-proof cable sheath material, comprising the following steps:

[0022] The polymer matrix is ​​vacuum dried at 40–60°C for 12–24 hours. The dried polymer matrix, inorganic flame retardant, and functional biomass rodent repellent are added to a high-speed mixer in proportion and mixed at 500–1200 rpm for 15–20 minutes to obtain a mixture. The mixture is then extruded and granulated at 100–120°C using a twin-screw extruder to obtain a modified material. The modified material, vulcanizing agent, and vulcanization accelerator are melted, blended, and extruded using a twin-screw extruder at 160–180°C. After cooling, curing, traction, pelletizing, and drying, a high-strength, high-toughness, low-smoke, halogen-free flame-retardant rodent-proof cable sheath material is obtained.

[0023] The present invention has the following beneficial effects:

[0024] This invention utilizes a polyurethane prepolymer containing capsaicin-terminated structures as a functional biomass rodent repellent. The capsaicin used for termination imparts rodent-repellent properties to the composite material, and the large molecular size of the rodent repellent reduces the irritant properties and migration rate of capsaicin, thereby improving the service stability and lifespan of the cable sheath material. The functional biomass rodent repellent of this invention can also form non-covalent interactions such as hydrogen bonds with the surface functional groups of flame retardants, improving their dispersion in the polymer matrix, constructing a solid filler network, and enhancing the mechanical properties and flame retardant efficiency of the material. The cable sheath material of this invention features high strength, high toughness, low smoke, halogen-free flame retardancy, and rodent repellency. Furthermore, the material has a simple preparation process and broad application prospects. Attached Figure Description

[0025] Figure 1 The Fourier transform infrared spectrum is shown for the functional biomass rodenticide prepared in Example 1 of this invention. Detailed Implementation

[0026] The present invention will now be described in more detail through specific embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0027] The raw material composition of the cable sheath material in the following embodiments and comparative examples is shown in Table 1:

[0028] Table 1. Raw materials and quantities of cable sheathing materials in each embodiment and comparative example (by mass parts).

[0029]

[0030] The inorganic flame retardant in the table is magnesium hydroxide, the vulcanizing agent is dicumyl peroxide, and the vulcanization accelerator is zinc oxide.

[0031] Example 1

[0032] The functional biomass rodenticide used in this embodiment is a polyurethane prepolymer containing a capsaicin-terminated structure, and its preparation includes the following steps:

[0033] 0.01 mol of PCDL2000 was placed in a reactor and stirred under vacuum at 100°C for 30 min. The temperature was then lowered to 80°C, and 0.02 mol of IPDI and 0.15 g of organic bismuth catalyst were added. The temperature was then raised to 90°C, and the reaction was mechanically stirred for 3 h. 0.02 mol of capsaicin and 10 mL of acetone were added to the reactor, and the reaction was continued at 90°C for 4 h. After the reaction was completed, the capsaicin-terminated polyurethane prepolymer was obtained after vacuum degassing at room temperature. Its structural formula is shown below:

[0034]

[0035] Figure 1 The image shows the Fourier transform infrared spectrum of the functional biomass rodenticide prepared in this embodiment. The characteristic peaks of specific groups in the image indicate that the functional biomass rodenticide prepared in this embodiment was successfully synthesized.

[0036] The raw materials and formula of the cable sheath material in this embodiment are shown in Table 1, and its preparation method is carried out according to the following steps:

[0037] First, polyethylene (PE, tensile strength 25 MPa, elongation at break 700%) was vacuum dried at 60℃ for 12 hours. Then, PE, inorganic flame retardant, and functional biomass rodent repellent were added to a high-speed mixer in proportion and mixed at 1000 rpm for 20 minutes to obtain a mixture. This mixture was then extruded and granulated at 100℃ using a twin-screw extruder to obtain a modified material. The modified material, vulcanizing agent, and vulcanization accelerator were melted, blended, and extruded using a twin-screw extruder at 170℃. After cooling, curing, traction, pelletizing, and drying, a high-strength, high-toughness, low-smoke, halogen-free flame-retardant cable sheath material was obtained.

[0038] Example 2

[0039] The raw materials and formulations of the cable sheath material in this embodiment are shown in Table 1. The preparation process is the same as in Example 1, except that polypropylene (PP, tensile strength of 20MPa, elongation at break of 600%) is used as the polymer matrix.

[0040] Example 3

[0041] The raw materials and formulations of the cable sheath material in this embodiment are shown in Table 1. The preparation process is the same as in Example 1, except that ethylene-vinyl acetate copolymer (EVA, tensile strength of 22 MPa, elongation at break of 800%) is used as the polymer matrix.

[0042] Comparative Example 1

[0043] The raw materials and formulations of this comparative example cable sheath material are shown in Table 1. The preparation method is the same as in Example 1, except that the amount of functional biomass rodent repellent added is 0.

[0044] Comparative Example 2

[0045] The raw materials and formulations of this comparative example cable sheath material are shown in Table 1. The preparation method is the same as in Example 2, except that the amount of functional biomass rodent repellent added is 0.

[0046] Comparative Example 3

[0047] The raw materials and formulas of this comparative example cable sheath material are shown in Table 1. The preparation method is the same as that of Example 3, except that the amount of functional biomass rodent repellent added is 0.

[0048] Comparative Example 4

[0049] The raw materials and formulas of the comparative cable sheath material are shown in Table 1. The preparation method is the same as that of Example 3, except that the amount of functional biomass rodent repellent added is 0, while 8 parts of capsaicin are directly added as rodent repellent.

[0050] Comparative Example 5

[0051] The raw materials and formulations of the comparative cable sheath material are shown in Table 1. The preparation method is the same as that of Example 3, except that the amount of functional biomass rodent repellent added is 0, and 8 parts of uncapsaicin-terminated polyurethane prepolymer (the preparation method is the same as that of capsaicin-terminated polyurethane prepolymer in Example 1, except that the amount of capsaicin added is 0) are directly added as rodent repellent.

[0052] The cable sheath materials prepared in the above comparative examples and embodiments were hot-pressed into test specimens, wherein the test standards were as follows:

[0053] Tensile strength, tested according to ISO 527-3:1995 standard, at a rate of 250 mm / min;

[0054] Elongation at break, tested according to ISO 527-3:1995 standard, at a rate of 250 mm / min;

[0055] Limiting oxygen index, tested according to ISO 4589-2:2096 standard;

[0056] Rodent-proof performance was tested according to GB / T 34016-2017 standard.

[0057] The main performance indicators of the cable sheath materials prepared in Examples 1-3 and Comparative Examples 1-5 are shown in Tables 2 and 3:

[0058] Table 2 Performance test results for each embodiment and comparative example

[0059]

[0060] Table 3. Test results of rodent-proof performance of each embodiment and comparative example.

[0061]

[0062] As shown in Tables 2 and 3, Example 3 has the best overall performance.

[0063] Compared to Example 3, although the capsaicin-terminated functional biomass rodent repellent synthesized from PCDL2000, IPDI, and capsaicin via a one-pot method can achieve simultaneous improvement in mechanical properties, flame retardant properties, and rodent repellent properties, its compatibility with PE and PP matrices is lower than that of EVA.

[0064] Compared to Example 1, Comparative Example 2 compared to Example 2, and Comparative Example 3 compared to Example 3, no functional biomass rodent repellent was introduced in Comparative Example 1. The highly filled inorganic particles tended to agglomerate in the matrix, making uniform distribution difficult. This resulted in poor mechanical properties, low flame retardant efficiency, and a lack of rodent-repellent properties. The introduction of functional biomass rodent repellent allows for the formation of non-covalent interactions such as hydrogen bonds with the surface functional groups of the inorganic flame retardant, improving its dispersion in the polymer matrix, constructing a solid filler network, and enhancing the material's mechanical properties and flame retardant efficiency. Furthermore, the introduction of capsaicin can improve the rodent-repellent properties of the cable sheath material.

[0065] Compared to Comparative Example 3, the addition of capsaicin alone can improve the rodent-repellent performance of cable sheath materials, but the tensile strength and flame retardant performance both decrease. The addition of uncapsaicin-terminated polyurethane prepolymer alone can improve the mechanical and flame retardant properties of cable sheath materials, but it cannot impart rodent-repellent properties to the cable sheath materials. The introduction of functional biomass rodent repellent can synergistically improve the mechanical properties, flame retardant properties and rodent-repellent properties of cable sheath materials.

[0066] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features. It should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application. Except for the technical features described in the specification, the remaining technical features are known to those skilled in the art. To highlight the innovative features of this invention, the remaining technical features will not be described further here.

Claims

1. A high-strength high-toughness low-smoke halogen-free flame-retardant rat-proof cable sheath material, characterized in that, The raw materials include, by mass fraction: ​ Polymer matrix 80.0~100.0 parts; Inorganic flame retardant 80.0~100.0 parts; Functional biomass rat repellent 2.0~8.0 parts; Vulcanizing agent 2.0~4.0 parts; Vulcanization accelerator 0.5~1.0 parts; The functional biomass rat repellent is a polyurethane prepolymer containing a capsaicin end-capped structure, and the structural general formula of the functional biomass rat repellent is: ; Wherein, R1 is a structural unit in bio-based diisocyanate, and R2 is a structural unit in bio-based diol.

2. The high-strength high-toughness low-smoke halogen-free flame-retardant rat-proof cable sheath material according to claim 1, characterized in that, The polymer matrix is one or more of polyethylene, polypropylene, ethylene-vinyl acetate copolymer and polyvinyl chloride blended together, wherein the tensile strength of the polymer matrix is 5~30 MPa, and the elongation at break is 150~800 %.

3. The high-strength high-toughness low-smoke halogen-free flame-retardant rodent-proof cable sheath material according to claim 1, characterized in that, The inorganic flame retardant is one or more of magnesium hydroxide, aluminum hydroxide and ammonium polyphosphate compounded together.

4. The high-strength high-toughness low-smoke halogen-free flame-retardant rodent-proof cable sheath material according to claim 1, characterized in that, The vulcanizing agent is one or more of 2,5 dimethyl-2,5 di(tert-butyl peroxy) hexane, benzoyl peroxide, di-tert-butyl peroxide and dicumyl peroxide compounded together.

5. The high-strength high-toughness low-smoke halogen-free flame-retardant rodent-proof cable sheath material according to claim 1, characterized in that, The vulcanization accelerator is one or more of metal oxides, triallyl cyanurate and trimethylolpropane triacrylate compounded together.

6. The high-strength high-toughness low-smoke halogen-free flame-retardant rodent-proof cable sheath material according to claim 1, characterized in that, The preparation method of the functional biomass rat repellent includes the following steps: (1) Add bio-based diol into a reactor, vacuum stir at 100~105 ℃ for 0.5~1.0 h to remove water contained in the bio-based diol; (2) Cool the water-removed bio-based diol in step (1) to 75~80 ℃, add bio-based diisocyanate and catalyst, warm up to 85~95 ℃, mechanically stir for 3~4 h; then add capsaicin and solvent, continue to react at 85~95 ℃ for 3~5 h; after the reaction is completed, vacuum deaeration at room temperature is performed, and the functional biomass rat repellent is obtained.

7. The high strength high toughness low smoke and zero halogen flame retardant rodent resistant cable jacketing compound of claim 6, wherein, The molar ratio of the bio-based diol, the bio-based diisocyanate and capsaicin is 1:2~3:2~4.

8. A process for preparing the high-strength high-ductility low-smoke halogen-free flame-retardant rodent-proof cable sheath material according to any one of claims 1 to 7, characterized in that, The following steps are included: Vacuum dry the polymer matrix at 40~60 ℃ for 12~24 h; add the dried polymer matrix, inorganic flame retardant and functional biomass rat repellent into a high-speed mixer according to the proportion, mix at a speed of 500~1200 rpm for 15~20 min to obtain a mixture, and then extrude and granulate through a twin-screw extruder at 100~120 ℃ to obtain a modified material; melt, blend, extrude the modified material, vulcanizing agent and vulcanization accelerator through a twin-screw extruder at 160~180 ℃, and then obtain a high-strength high-toughness low-smoke halogen-free flame-retardant rat-proof cable sheath material after cooling and solidification, traction, cutting, drying.

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