Halogen-free low-smoke insulated cable and preparation method thereof

Abstract

The present invention discloses a halogen-free, low-smoke insulated cable and a preparation method thereof, belonging to the technical field of wires and cables. The cable produced by the present invention has a protective sheath material based on high-density polyethylene, which gives the cable good mechanical and insulating properties; glass fiber is added to the material of the protective sheath to further improve the mechanical strength of the cable; a flame retardant modifier is produced through a series of reactions, and the flame retardant modifier molecule contains three flame retardant components, which greatly enhances the flame retardant properties of the cable and can further improve the mechanical properties of the cable; therefore, the cable produced by the present invention has good insulation properties, excellent mechanical properties, and efficient flame retardant and smoke suppression properties, is halogen-free, and is environmentally friendly, and has important application value in the technical field of wires and cables.

Description

Technical Field

[0001] The present invention belongs to the technical field of wires and cables, and in particular relates to a halogen-free low-smoke insulated cable and a preparation method thereof. Background Art

[0002] A cable is a conductive medium, typically consisting of several or several groups of conductors (at least two in each group) twisted together into a rope-like structure. Each group of conductors is insulated from each other and often twisted around a central core. The entire cable is covered with a highly insulating coating, resulting in a cable with internal conduction and external insulation. It is widely used in various fields, including petrochemicals, computers, and national defense.

[0003] In recent years, the booming wire and cable industry has placed higher demands on cables. Different cable applications also necessitate different performance requirements. Generally speaking, cables must exhibit excellent mechanical properties, insulation, and corrosion resistance. The outermost protective layer has the greatest impact on cable performance. To ensure the insulation of cables, organic polymers are used. However, these materials typically have a low oxygen index, poor flame retardancy, and are easily ignited. Therefore, flame retardants are often added to improve the flame retardancy of cables.

[0004] At present, the commonly used flame retardants on the market are still mainly halogen and halogen-antimony flame retardants. However, these halogen flame retardant materials release a large amount of smoke and toxic and harmful hydrogen halide gas when burning. Since its diffusion speed is much faster than the flame diffusion speed, it is easy to hinder the rapid evacuation and fire fighting of personnel, causing serious impact and loss of people's lives and property safety. Therefore, the above problems need to be solved to meet the higher demands in the field of wire and cable technology. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a halogen-free low-smoke insulated cable and a preparation method thereof.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A halogen-free low-smoke insulated cable comprises a protective sheath, a metal shielding layer, an insulating layer and a conductor from the outside to the inside.

[0008] Furthermore, the conductor is made of copper.

[0009] Furthermore, the material of the insulating layer is high-density polyethylene.

[0010] Furthermore, the material of the metal shielding layer is copper tape.

[0011] Furthermore, the material of the protective cover includes the following raw materials in parts by weight: 60-80 parts of high-density polyethylene, 4-6 parts of glass fiber, 6-14 parts of flame retardant modifier, 3-5 parts of antioxidant, and 2-5 parts of processing aid.

[0012] Furthermore, the antioxidant is a hindered phenol antioxidant.

[0013] Furthermore, the processing aid is one or more of paraffin, stearic acid, calcium stearate and zinc stearate.

[0014] The material of the protective cover is based on high-density polyethylene, which gives the material good mechanical properties and insulation properties; adding a small amount of glass fiber can further improve the mechanical properties of the material; the added processing aid makes the raw materials more dispersed and easy to process.

[0015] Furthermore, the flame retardant modifier is prepared by the following steps:

[0016] A1. Toluene and phosphorus trichloride were mixed in a flask, heated to 45° C., and stirred continuously until the phosphorus trichloride was completely dissolved. Pentaerythritol was then slowly added and reacted under vacuum for 6 h. After the reaction was complete, the mixture was cooled to room temperature, filtered, evaporated, and crystallized to obtain intermediate 1. The ratio of toluene, phosphorus trichloride, and pentaerythritol used was 100 mL: 27.2 g: 13.6 g.

[0017]

[0018] The hydroxyl group in pentaerythritol acts as a nucleophile to attack the phosphorus atom in phosphorus trichloride. The lone pair of electrons on the phosphorus atom forms a coordination bond with the oxygen atom of the hydroxyl group. At the same time, the chlorine atom on the phosphorus atom is replaced to obtain intermediate 1.

[0019] A2, intermediate product 1, n-decylamine, triethylamine (acid binding agent) and tetrahydrofuran (THF) are mixed and stirred in a three-necked flask equipped with a thermometer and a stirring apparatus, then the apparatus is placed on a heating mantle, the temperature is gradually raised to 56 ° C, and the reaction is incubated for 6 hours. The reaction is complete, filtered, and part of the solvent is removed by rotary evaporation. Then, the eluent is purified by column chromatography (eluent adopts a mixed solvent of petroleum ether / ethyl acetate in a volume ratio of 5:1), and the eluent is removed by rotary evaporation to obtain intermediate product 2; the ratio of the amount of intermediate product 1, n-decylamine, triethylamine, and tetrahydrofuran is 27.3g:15.7g:15mL:100mL;

[0020] Under the catalysis of triethylamine, intermediate product 1 and n-decylamine undergo a nucleophilic substitution reaction, and by controlling the molar ratio of the two to be close to 1:1 and a slight excess of intermediate product 1, intermediate product 2 is obtained. The specific reaction process is as follows:

[0021]

[0022] A3. 4-hydroxyphenylboric acid and N,N-dimethylformamide were placed in a three-necked flask, stirred under an ice bath at 5°C, and triethylamine and intermediate 2 were added in sequence. The device was placed on a heating mantle, and the temperature was gradually increased to 60°C. The reaction was carried out for 5 hours. Stirring was continued during the reaction. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the mixture was washed with deionized water and dried in an oven to obtain a flame retardant modifier; the ratio of 4-hydroxyphenylboric acid, N,N-dimethylformamide, triethylamine, and intermediate 2 was 13.8g:120mL:10mL:38.5g;

[0023] Under the catalysis of triethylamine, 4-hydroxyphenylboronic acid reacts with the intermediate product 2 to undergo a nucleophilic substitution reaction to obtain a flame retardant modifier. The specific reaction process is as follows:

[0024]

[0025] The flame retardant modifier molecule contains PN flame retardant component, which is an excellent halogen-free flame retardant component with synergistic flame retardant effect of phosphorus and nitrogen flame retardants, which can give the protective cover environmentally friendly and efficient flame retardant performance; moreover, the flame retardant modifier molecule also contains organic boron flame retardant component, which is a condensed phase flame retardant. When burned, it will generate boric anhydride or boric acid, which will form a glassy molten covering during thermal decomposition, hindering the overflow of combustible gas. Moreover, the boric acid structure will form a boron-oxygen six-ring network structure when heated, further After the first step is heated, a BOC carbon layer is formed covering the surface of the epoxy resin, reducing heat transfer and inhibiting the diffusion of combustible decomposition products, and promoting carbonization. Therefore, the flame retardant modifier molecule contains three flame retardant components, which can play a synergistic role, which greatly enhances the flame retardant and smoke suppression properties of the protective cover. In addition, the flame retardant modifier molecule also contains a long carbon chain structure. The long carbon chain belongs to the methylene chain segment, which can improve the mechanical properties of the protective cover and can be interspersed in the macromolecular chain of polyethylene, thereby improving the stability of the flame retardant modifier and ensuring that the performance of the flame retardant modifier can be stably exerted.

[0026] A method for preparing a halogen-free low-smoke insulated cable comprises the following steps:

[0027] Copper wire is used as the conductor, high-density polyethylene is extruded on the conductor to form an insulation layer, copper tape is wrapped around the surface of the insulation layer to form a metal shielding layer, and then the material of the protective sheath is extruded and coated on the metal shielding layer to obtain a halogen-free and low-smoke insulated cable.

[0028] Beneficial effects of the present invention:

[0029] 1. The cable produced by the present invention has a protective sheath made of high-density polyethylene as a matrix, which gives the cable good mechanical properties and insulation properties;

[0030] 2. Adding glass fiber to the material of the protective cover further improves the mechanical strength of the cable;

[0031] 3. The flame retardant modifier is prepared through a series of reactions. The flame retardant modifier molecule contains three flame retardant components, which greatly enhances the flame retardant and smoke suppression performance of the cable and can further improve the mechanical properties of the cable;

[0032] Therefore, the cable prepared by the present invention has good insulation performance, excellent mechanical properties, high-efficiency flame retardant and smoke suppression performance, is halogen-free, environmentally friendly, and has important application value in the field of wire and cable technology. DETAILED DESCRIPTION

[0033] 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.

[0034] Example 1

[0035] Preparation of flame retardant modifier:

[0036] A1. Mix 100 mL of toluene and 27.2 g of phosphorus trichloride in a flask, heat to 45°C, and stir continuously until the phosphorus trichloride is completely dissolved. Then, slowly add 13.6 g of pentaerythritol and react under vacuum for 6 h. After the reaction is complete, cool to room temperature, filter, evaporate, and crystallize to obtain intermediate 1.

[0037] A2, 27.3g of intermediate product 1, 15.7g of n-decylamine, 15mL of triethylamine and 100mL of tetrahydrofuran were mixed and stirred in a three-necked flask equipped with a thermometer and a stirring device, and then the device was placed on a heating mantle, and the temperature was gradually increased to 56 ° C. The reaction was kept incubated for 6h. After the reaction was completed, it was filtered, and part of the solvent was removed by rotary evaporation. It was then purified by column chromatography (eluent using a mixed solvent of petroleum ether / ethyl acetate, the volume ratio of the two being 5:1), and the eluent was removed by rotary evaporation to obtain intermediate product 2;

[0038] A3. Place 13.8 g of 4-hydroxyphenylboric acid and 120 mL of N,N-dimethylformamide in a three-necked flask, stir in an ice bath at 5°C, and add 10 mL of triethylamine and 38.5 g of intermediate 2 in sequence. Place the apparatus on a heating mantle, gradually increase the temperature to 60°C, and react for 5 h with continuous stirring during the reaction. After the reaction is complete, remove the solvent by distillation under reduced pressure, wash with deionized water, and dry in an oven to obtain a flame retardant modifier.

[0039] Example 2

[0040] Preparation of flame retardant modifier:

[0041] A1. Mix 200 mL of toluene and 54.4 g of phosphorus trichloride in a flask, heat to 45°C, and stir continuously until the phosphorus trichloride is completely dissolved. Then, slowly add 27.2 g of pentaerythritol and react under vacuum for 6 h. After the reaction is complete, cool to room temperature, filter, evaporate, and crystallize to obtain intermediate 1.

[0042] A2, 54.6g intermediate product 1, 31.4g n-decylamine, 30mL triethylamine and 200mL tetrahydrofuran were mixed and stirred in a three-necked flask equipped with a thermometer and a stirring device, and then the device was placed on a heating mantle, and the temperature was gradually increased to 56 ° C. The reaction was kept incubated for 6h. After the reaction was completed, it was filtered, and part of the solvent was removed by rotary evaporation. Then, it was purified by column chromatography (eluent was a mixed solvent of petroleum ether / ethyl acetate, and the volume ratio of the two was 5:1), and the eluent was removed by rotary evaporation to obtain intermediate product 2;

[0043] A3. 27.6 g of 4-hydroxyphenylboric acid and 240 mL of N,N-dimethylformamide were placed in a three-necked flask and stirred in an ice bath at 5°C. 20 mL of triethylamine and 77.0 g of intermediate 2 were added in sequence. The apparatus was placed on a heating mantle and the temperature was gradually increased to 60°C. The reaction was carried out for 5 h with continuous stirring during the reaction. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the mixture was washed with deionized water and dried in an oven to obtain a flame retardant modifier.

[0044] Example 3

[0045] Preparation of protective cover materials:

[0046] 60 g of high-density polyethylene, 4 g of glass fiber, 6 g of the flame retardant modifier prepared in Example 1, and 3 g of antioxidant 1010 were dried; the dried polycarbonate resin was stirred in a high-speed mixer at a speed of 200 rpm for 5 minutes, and then the glass fiber, flame retardant modifier, antioxidant 1010, and 2 g of paraffin were added. After stirring for another 5 minutes, the resulting mixture was fed into a twin-screw extruder at a speed of 300 rpm for melt extrusion to obtain a protective cover material.

[0047] Example 4

[0048] Preparation of protective cover materials:

[0049] 70 g of high-density polyethylene, 5 g of glass fiber, 10 g of the flame retardant modifier prepared in Example 1, and 4 g of antioxidant 1010 were dried; the dried polycarbonate resin was stirred in a high-speed mixer at 400 rpm for 5 minutes, and then the glass fiber, flame retardant modifier, antioxidant 1010, and 4 g of stearic acid were added. After stirring for another 5 minutes, the resulting mixture was fed into a twin-screw extruder at a speed of 300 rpm for melt extrusion to obtain a protective cover material.

[0050] Example 5

[0051] Preparation of protective cover materials:

[0052] 80 g of high-density polyethylene, 6 g of glass fiber, 14 g of the flame retardant modifier prepared in Example 1, and 5 g of antioxidant 1010 were dried; the dried polycarbonate resin was stirred in a high-speed mixer at 400 rpm for 5 minutes, and then the glass fiber, flame retardant modifier, antioxidant 1010, and 5 g of calcium stearate were added. After stirring for another 5 minutes, the resulting mixture was fed into a twin-screw extruder at a speed of 300 rpm for melt extrusion to obtain a protective cover material.

[0053] Example 6

[0054] A copper wire was used as a conductor, and high-density polyethylene was extruded on the conductor to form an insulating layer. A copper tape was wrapped around the surface of the insulating layer to form a metal shielding layer. Then, 80 g of high-density polyethylene, 6 g of glass fiber, 14 g of the flame retardant modifier prepared in Example 1, and 5 g of antioxidant 1010 were dried. The dried polycarbonate resin was stirred in a high-speed mixer at a speed of 400 rpm for 5 minutes, and then the glass fiber, flame retardant modifier, antioxidant 1010, and 5 g of calcium stearate were added. After stirring for another 5 minutes, the resulting mixture was fed into a twin-screw extruder at a speed of 300 rpm for melt blending, and then extruded and coated on the surface of the metal shielding layer to obtain a halogen-free low-smoke insulated cable.

[0055] Comparative Example 1

[0056] The flame retardant modifier in Example 5 was replaced with a commercially available halogen flame retardant, and the remaining steps were the same as those in Example 5 to obtain a material.

[0057] Comparative Example 2

[0058] Use commercially available flame retardant polyethylene cable material.

[0059] Examples 3, 4, and 5, and Comparative Examples 1 and 2 were made into corresponding test shapes according to different test standards, and the following performance tests were performed:

[0060] The tensile properties were determined using the national standard GB / T 1040.2 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics";

[0061] The limiting oxygen index of the sample is determined using the national standard GB / T 2406 "Test method for combustion performance of plastics";

[0062] The smoke density is measured using the national standard GB / T 8323.2 "Plastic smoke generation Part 2: Single chamber method for determination of smoke density test method";

[0063] The measured results are shown in the following table:

[0064] Test items Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Tensile strength / MPa 23.3 24.1 24.5 22.7 22.1 Limiting oxygen index / % 29.4 30.0 30.5 28.7 27.3 Smoke density 118 112 103 186 173

[0065] As can be seen from the above table, the protective sheath material prepared in the embodiment of the present invention has higher mechanical properties and flame retardant and smoke suppression properties than the control example, and is halogen-free. When used in cables, it can be endowed with corresponding properties. Therefore, the present invention has important application value in the field of wire and cable technology.

[0066] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0067] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A halogen-free low-smoke insulated cable, comprising, from outside to inside, a protective sheath, a metal shielding layer, an insulating layer, and a conductor, characterized in that: The material of the protective cover includes the following raw materials in parts by weight: 60-80 parts of high-density polyethylene, 4-6 parts of glass fiber, 6-14 parts of flame retardant modifier, 3-5 parts of antioxidant, and 2-5 parts of processing aid; Wherein, the flame retardant modifier is prepared by the following steps: A1. Mix toluene and phosphorus trichloride in a flask, heat to 45°C, and stir continuously until the phosphorus trichloride is completely dissolved. Then, slowly add pentaerythritol and react under vacuum for 6 hours. After the reaction is complete, cool to room temperature, filter, evaporate, and crystallize to obtain intermediate 1. A2. Mix the intermediate product 1, n-decylamine, triethylamine, and tetrahydrofuran in a three-necked flask and stir until uniform. Then, place the apparatus on a heating mantle and heat at 56°C for 6 h. After the reaction is complete, filter, rotary evaporate, purify by column chromatography, and rotary evaporate to obtain the intermediate product 2. A3. 4-Hydroxyphenylboric acid and N,N-dimethylformamide were placed in a three-necked flask and stirred in an ice bath at 5°C. Triethylamine and intermediate 2 were added in sequence. The apparatus was placed on a heating mantle and reacted at 60°C for 5 hours with continuous stirring. After the reaction was complete, the mixture was evaporated under reduced pressure, washed with deionized water, and dried in an oven to obtain a flame retardant modifier. Among them, the ratio of toluene, phosphorus trichloride, and pentaerythritol used in step A1 is 100 mL: 27.2 g: 13.6 g; the ratio of intermediate product 1, n-decylamine, triethylamine, and tetrahydrofuran used in step A2 is 27.3 g: 15.7 g: 15 mL: 100 mL; and the ratio of 4-hydroxyphenylboric acid, N,N-dimethylformamide, triethylamine, and intermediate product 2 used in step A3 is 13.8 g: 120 mL: 10 mL: 38.5 g.

2. The halogen-free low-smoke insulated cable according to claim 1, characterized in that: The antioxidant is a hindered phenol antioxidant.

3. The halogen-free low-smoke insulated cable according to claim 1, characterized in that: The processing aid is one or more of paraffin, stearic acid, calcium stearate and zinc stearate.

4. The method for preparing a halogen-free low-smoke insulated cable according to claim 1, characterized in that: The following steps are involved: Copper wire is used as the conductor, high-density polyethylene is extruded on the conductor to form an insulation layer, copper tape is wrapped around the surface of the insulation layer to form a metal shielding layer, and then the material of the protective sheath is extruded and coated on the metal shielding layer to obtain a halogen-free and low-smoke insulated cable.

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