A termite-proof and flame-retardant cable and its preparation method

Abstract

This invention relates to the field of cable technology and proposes a termite-proof and flame-retardant cable and its preparation method. The termite-proof and flame-retardant cable comprises, from the inside out, a conductor, an insulation layer, and a protective layer. The protective layer is made of the following components by weight: 90-100 parts mineral fiber-filled nylon resin, 2-3 parts termite repellent, 1-2 parts plasticizer, 5-7 parts flame retardant, and 2-3 parts carbon black. The mineral fiber-filled nylon resin includes a first mineral fiber-filled nylon resin and a second mineral fiber-filled nylon resin; the mineral fiber content of the first mineral fiber-filled nylon resin is lower than that of the second mineral fiber-filled nylon resin. This technical solution solves the problem of poor mechanical properties in existing termite-proof and flame-retardant cables.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to an anti-termite and flame-retardant cable and its preparation method. Background Technology

[0002] With the acceleration of urbanization and the rapid development of energy infrastructure, the safety and reliability of cables, as the "nerveline" of modern society, are receiving increasing attention. In humid environments, termite infestation has become one of the main factors threatening the long-term stable operation of cables. The acidic substances secreted by termites can corrode the cable sheath, leading to insulation damage, short circuits, and even fires, causing significant economic losses and safety hazards.

[0003] Physical termite control utilizes the hardness and smoothness of the termite-resistant sheathing material on cables to prevent termites from biting and thus achieve termite prevention. This method is highly environmentally friendly. Besides metallic materials, typical non-metallic materials include nylon. Cables also require good flame retardant and mechanical properties to extend their service life. Therefore, developing cables that combine highly effective termite control with good flame retardant and mechanical properties has become a key technological direction urgently needing breakthroughs in the cable materials field. Summary of the Invention

[0004] This invention proposes a termite-proof and flame-retardant cable and its preparation method, which solves the problem of poor mechanical properties of termite-proof and flame-retardant cables in related technologies.

[0005] The technical solution of the present invention is as follows:

[0006] This invention proposes a termite-proof and flame-retardant cable, comprising, from the inside out, a wire core, an insulation layer, and a protective layer. The protective layer is made of the following components by weight: 90-100 parts mineral fiber-filled nylon resin, 2-3 parts termite repellent, 1-2 parts plasticizer, 5-7 parts flame retardant, and 2-3 parts carbon black. The mineral fiber-filled nylon resin includes a first mineral fiber-filled nylon resin and a second mineral fiber-filled nylon resin. The mineral fiber content of the first mineral fiber-filled nylon resin is lower than that of the second mineral fiber-filled nylon resin.

[0007] As a further technical solution, the mineral fiber content of the first mineral fiber-filled nylon resin is 20wt%, and the mineral fiber content of the second mineral fiber-filled nylon resin is 30wt%.

[0008] As a further technical solution, the mass ratio of the first mineral fiber-filled nylon resin and the second mineral fiber-filled nylon resin is 1:4 to 7.

[0009] As a further technical solution, the raw material of the protective layer also includes 20 to 40 parts of modified masterbatch, wherein the modified masterbatch includes polyethylene, ethylene-vinyl acetate copolymer, and polyolefin thermoplastic elastomer.

[0010] As a further technical solution, the mass ratio of the polyethylene, ethylene-vinyl acetate copolymer, and polyolefin thermoplastic elastomer is 1:1.5~2:1.5~2.

[0011] As a further technical solution, the plasticizer includes one or more of N-butylbenzenesulfonamide, pentaerythritol stearate, and polypropylene adipate.

[0012] The addition of plasticizers can weaken the intermolecular forces and lower the glass transition temperature of the resin, enabling the cable protective layer to maintain a certain strength while having better flexibility and elasticity. In addition, plasticizers can also improve the flowability of materials during processing, reduce melt viscosity, reduce energy consumption during extrusion, and improve production efficiency.

[0013] As a further technical solution, the flame retardant includes one or both of magnesium hydroxide and aluminum hydroxide.

[0014] Flame retardants such as magnesium hydroxide and aluminum hydroxide undergo decomposition reactions at high temperatures, absorbing a large amount of heat, thereby reducing the surface temperature of the cable material and inhibiting its thermal decomposition and combustion. The water vapor produced during decomposition also dilutes the oxygen concentration in the combustion zone, further suppressing combustion.

[0015] As a further technical solution, the carbon black is obtained by modifying carbon black with 2-hydroxyquinoline-4-carboxylic acid.

[0016] As a further technical solution, the method for preparing carbon black includes the following steps: 2-hydroxyquinoline-4-carboxylic acid is added to anhydrous ethanol and dispersed evenly, then carbon black is added and mixed, and dried to obtain carbon black.

[0017] As a further technical solution, the amount of 2-hydroxyquinoline-4-carboxylic acid added is 3% to 5% of the mass of carbon black.

[0018] As a further technical solution, the volume-to-mass ratio of ethanol to carbon black is 10 mL: 1 g.

[0019] As a further technical solution, the mixing time is 1~2 hours.

[0020] This invention also proposes a method for preparing an anti-termite and flame-retardant cable, comprising the following steps:

[0021] S1. Extruding the insulating material to cover the outside of the wire core to form an insulating layer;

[0022] S2. Mix the raw materials of the protective layer evenly, extrude them, and coat the outside of the insulation layer to obtain the termite-proof and flame-retardant cable.

[0023] As a further technical solution, the mineral fiber-filled nylon resin, polyethylene, ethylene-vinyl acetate copolymer, and polyolefin thermoplastic elastomer are dried at 80°C for 4 hours before use.

[0024] As a further technical solution, the equipment used for mixing is a high-speed mixer with a temperature of 30℃~80℃, a time of 15~30min, and a rotation speed of 1300rpm.

[0025] As a further technical solution, the extrusion temperature is 200~280℃.

[0026] As a further technical solution, the extrusion adopts a twin-screw extruder with a feed rate of 140 g / min and the working temperature is set from zone one to zone five as 200℃, 220℃, 240℃, 260℃ and 280℃ respectively.

[0027] The working principle and beneficial effects of this invention are as follows:

[0028] This invention provides a termite-proof and flame-retardant cable. The cable uses two types of mineral fiber-filled nylon resins with different mineral fiber filling amounts as the main materials, resulting in a cable that combines highly effective termite protection with excellent flame retardancy and mechanical properties. Using only a single high-mineral-fiber-filled nylon resin will lead to uneven dispersion of the mineral fibers due to excessive content, forming stress concentration points and causing a decrease in mechanical properties. Conversely, using only a single low-mineral-fiber-filled nylon resin will result in insufficient mechanical properties due to insufficient mineral fiber content. Therefore, this invention innovatively uses a compound of two nylon resins with different mineral fiber filling amounts. The low-filled nylon dilutes the mineral concentration of the high-filled system, while simultaneously promoting fiber dispersion during processing, reducing agglomeration, and improving stress transfer efficiency, thereby enhancing tensile strength and elongation at break. 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] In the following embodiments and comparative examples:

[0031] The first mineral fiber filled nylon resin is 20wt% mineral fiber filled; model: 1200TC; manufacturer: Guangdong Sange New Materials Co., Ltd.

[0032] The second mineral fiber-filled nylon resin is 30wt% mineral fiber filler; Model: 1300TC; Manufacturer: Guangdong Sange New Materials Co., Ltd.

[0033] Polyethylene: LDPE Yanshan Petrochemical LD166;

[0034] Ethylene-vinyl acetate copolymer: EVA Lotte VC710 (Korea);

[0035] Polyolefin thermoplastic elastomer: POE DuPont 8150.

[0036] Example 1

[0037] An anti-termite and flame-retardant cable comprises, from the inside out, a wire core, an insulation layer, and a protective layer. The protective layer is made of the following components by weight: 90 parts mineral fiber-filled nylon resin, 2 parts cypermethrin, 1 part pentaerythritol stearate, 5 parts aluminum hydroxide, 2 parts carbon black, and 20 parts modified masterbatch. The modified masterbatch comprises polyethylene, ethylene-vinyl acetate copolymer, and polyolefin thermoplastic elastomer in a mass ratio of 1:2:2. The mineral fiber-filled nylon resin is composed of a first mineral fiber-filled nylon resin and a second mineral fiber-filled nylon resin in a mass ratio of 1:4.

[0038] A method for preparing an anti-termite and flame-retardant cable includes the following steps:

[0039] S1. Extruding the insulating material to cover the outside of the wire core to form an insulating layer;

[0040] S2. The raw materials for the protective layer are mixed evenly in a high-speed mixer, and then melt-blended and extruded through a twin-screw extruder to coat the outside of the insulation layer, thus obtaining a termite-proof and flame-retardant cable. The mixing temperature is 60℃, the mixing time is 20 minutes, and the speed is 1300 rpm; the twin-screw extruder feed rate is 140 g / min, and the operating temperatures for zones one through five are set to 200℃, 220℃, 240℃, 260℃, and 280℃ respectively.

[0041] Example 2

[0042] An anti-termite and flame-retardant cable comprises, from the inside out, a conductor, an insulation layer, and a protective layer. The protective layer is made of the following components by weight: 100 parts mineral fiber-filled nylon resin, 3 parts cypermethrin, 2 parts pentaerythritol stearate, 7 parts aluminum hydroxide, 3 parts carbon black, and 40 parts modified masterbatch. The modified masterbatch comprises polyethylene, ethylene-vinyl acetate copolymer, and polyolefin thermoplastic elastomer in a mass ratio of 1:1.5:1.5. The mineral fiber-filled nylon resin is composed of a first mineral fiber-filled nylon resin and a second mineral fiber-filled nylon resin in a mass ratio of 1:7.

[0043] A method for preparing an anti-termite and flame-retardant cable includes the following steps:

[0044] S1. Extruding the insulating material to cover the outside of the wire core to form an insulating layer;

[0045] S2. The raw materials for the protective layer are mixed evenly in a high-speed mixer, and then melt-blended and extruded through a twin-screw extruder to coat the outside of the insulation layer, thus obtaining a termite-proof and flame-retardant cable. The mixing temperature is 60℃, the mixing time is 20 minutes, and the speed is 1300 rpm; the twin-screw extruder feed rate is 140 g / min, and the operating temperatures for zones one through five are set to 200℃, 220℃, 240℃, 260℃, and 280℃ respectively.

[0046] Example 3

[0047] The only difference between this embodiment and Example 1 is that carbon black is replaced with modified carbon black. The preparation method of modified carbon black includes the following steps: 2-hydroxyquinoline-4-carboxylic acid (3% of the mass of carbon black) is added to anhydrous ethanol (100 mL) and dispersed evenly, then carbon black (10 g) is added and mixed for 1.5 h, and dried to obtain modified carbon black.

[0048] Example 4

[0049] The only difference between this embodiment and Example 3 is that 2-hydroxyquinoline-4-carboxylic acid is replaced with an equal amount of silane coupling agent KH550.

[0050] Example 5

[0051] The only difference between this embodiment and Example 3 is that the carbon black was modified with 2-hydroxyquinoline-4-carboxylic acid (4% of the carbon black mass).

[0052] Example 6

[0053] The only difference between this embodiment and Example 3 is that the carbon black was modified with 2-hydroxyquinoline-4-carboxylic acid (5% of the carbon black mass).

[0054] Comparative Example 1

[0055] The only difference between this comparative example and Example 1 is that the mineral fiber filled nylon resin is the first mineral fiber filled nylon resin.

[0056] Comparative Example 2

[0057] The only difference between this comparative example and Example 1 is that the mineral fiber-filled nylon resin is a second mineral fiber-filled nylon resin.

[0058] Experimental Example 1

[0059] The protective layers of the termite-proof and flame-retardant cables prepared in Examples 1-6 and Comparative Examples 1-2 were tested according to the following method:

[0060] 1. Flame retardant performance: The oxygen index was tested according to GB / T 2406.2-2009 "Determination of burning behavior of plastics by oxygen index method - Part 2: Room temperature test". The sample shape was IV, and the test result was the average value of 3 samples.

[0061] 2. Mechanical properties: The tensile strength and elongation at break were tested according to GB / T 2951.11-2008 "General test methods for insulation and sheath materials of cables and optical cables - Part 11: General test methods for thickness and dimensional measurement of mechanical properties". The test specimens were dumbbell specimens with a thickness of 3 mm. The test results were the average value of 5 specimens.

[0062] The test results are recorded in Table 1. In Table 1, " / " indicates that this performance was not tested.

[0063] Table 1. Test results of flame retardant and mechanical properties of Examples 1-6 and Comparative Examples 1-2

[0064]

[0065] Comparing Examples 1-6 with Comparative Examples 1-2, it is demonstrated that the present invention, by filling nylon with different contents of mineral fibers, can improve tensile strength and elongation at break. Furthermore, the oxygen index of the protective layer is above 35.6%, exhibiting good flame retardancy.

[0066] Compared with Examples 1 and 4, Examples 3 and 5-6 demonstrate that by adding carbon black modified with 2-hydroxyquinoline-4-carboxylic acid, the present invention can further improve tensile strength and elongation at break.

[0067] 3. Termite resistance test: The termite infestation level was tested according to the experimental group method in JB / T 10696.9-2011 "Mechanical and physical and chemical properties test methods for wires and cables - Part 9: Termite test".

[0068] Three samples were tested for each embodiment. It was found that no termite tooth marks were found on the surface and along the edges of the samples. No termite tooth marks were found on the surface of the termite-proof and flame-retardant cables. The termite infestation level was 1 for all samples. This proves that the termite-proof and flame-retardant cables prepared in Examples 1 to 6 have good termite-proof effect.

[0069] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A termite-proof and flame-retardant cable, characterized in that, From the inside out, it includes a wire core, an insulation layer, and a protective layer. The raw materials of the protective layer include the following components by weight: 90-100 parts of mineral fiber filled nylon resin, 2-3 parts of termite repellent, 1-2 parts of plasticizer, 5-7 parts of flame retardant, and 2-3 parts of carbon black. The mineral fiber filled nylon resin includes a first mineral fiber filled nylon resin and a second mineral fiber filled nylon resin. The mineral fiber content of the first mineral fiber filled nylon resin is 20 wt%, and the mineral fiber content of the second mineral fiber filled nylon resin is 30 wt%. The carbon black is obtained by modifying carbon black with 2-hydroxyquinoline-4-carboxylic acid.

2. The termite-proof and flame-retardant cable according to claim 1, characterized in that, The mass ratio of the first mineral fiber-filled nylon resin to the second mineral fiber-filled nylon resin is 1:4 to 7.

3. The termite-proof and flame-retardant cable according to claim 1, characterized in that, The raw materials for the protective layer also include 20 to 40 parts of modified masterbatch, which includes polyethylene, ethylene-vinyl acetate copolymer, and polyolefin thermoplastic elastomer.

4. The termite-proof and flame-retardant cable according to claim 1, characterized in that, The plasticizer includes one or more of N-butylbenzenesulfonamide, pentaerythritol stearate, and polypropylene adipate.

5. The termite-proof and flame-retardant cable according to claim 1, characterized in that, The flame retardant includes one or both of magnesium hydroxide and aluminum hydroxide.

6. A method for preparing a termite-proof and flame-retardant cable, used to prepare the termite-proof and flame-retardant cable according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Extruding the insulating material to cover the outside of the wire core to form an insulating layer; S2. Mix the raw materials of the protective layer evenly, and extrude them to coat the outside of the insulation layer to obtain the termite-proof and flame-retardant cable.

7. The method for preparing an anti-termite and flame-retardant cable according to claim 6, characterized in that, In step S2, the mixing temperature is 30℃~80℃ and the time is 15~30min.

8. The method for preparing an anti-termite and flame-retardant cable according to claim 6, characterized in that, In step S2, the temperature during extrusion is 200~280℃.

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