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

Abstract

The invention discloses a halogen-free low-smoke insulated cable and a preparation method thereof, and belongs to the technical field of wires and cables. According to the cable prepared by the invention, the material of the protective sleeve takes high-density polyethylene as a matrix, so that the cable is endowed with good mechanical property and insulating property; the glass fiber is added into the material of the protective sleeve, so that the mechanical strength of the cable is further improved; the flame-retardant modifier is prepared through a series of reactions, and molecules of the flame-retardant modifier contain three flame-retardant components, so that the flame-retardant property of the cable is greatly enhanced, and the mechanical property of the cable can be further improved; therefore, the cable prepared by the invention is good in insulating property, excellent in mechanical property, efficient in flame retardant and smoke suppression performance, halogen-free and environment-friendly, and has an important application value in the technical field of wires and cables.

Description

Technical Field

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

[0002] Cable is a conductive medium, usually a rope-like cable made of several or several groups of wires (at least two in each group). Each group of wires is insulated from each other and often twisted around a center. The entire outer layer is covered with a highly insulating covering. The cable has the characteristics of internal power supply and external insulation. It is widely used in various fields such as petrochemical, computer, and national defense.

[0003] In recent years, with the vigorous development of the wire and cable industry, higher requirements have been put forward for cables. And according to the different application sites of cables, different performance requirements will be placed on cables. Generally speaking, cables need to have good mechanical properties, insulation and corrosion resistance. The biggest influence on the performance of cables is its outermost protective layer. In order to ensure the insulation of cables, organic polymers are used, but such materials usually have a low oxygen index, poor flame retardancy and are easy to burn. 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 their diffusion speed is much faster than the flame diffusion speed, they can easily hinder the rapid evacuation of personnel and fire fighting, causing serious impact and loss on people’s lives and property safety. Therefore, the above problems need to be solved to meet 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 in sequence 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 prepared 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 material more dispersed and easy to process.

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

[0016] A1. Mix toluene and phosphorus trichloride in a flask, heat to 45° C., stir continuously until the phosphorus trichloride is completely dissolved, then slowly add pentaerythritol, react for 6 hours under vacuum conditions, and after the reaction is completed, cool to room temperature, filter, evaporate, and crystallize to obtain intermediate 1; the ratio of toluene, phosphorus trichloride, and pentaerythritol is 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, and the chlorine atom on the phosphorus atom is replaced to obtain the intermediate 1.

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

[0020] Under the catalysis of triethylamine, intermediate product 1 and n-decylamine undergo a nucleophilic substitution reaction, and intermediate product 2 is obtained by controlling the molar ratio of the two to be close to 1:1 and the intermediate product 1 to be slightly excessive; 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 product 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 continued for 5 hours, and stirring was continued during the reaction. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and then 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 product 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 molecules contain PN flame retardant components, which are excellent halogen-free flame retardant components. They have the synergistic flame retardant effects of phosphorus and nitrogen flame retardants, and can give the protective cover environmentally friendly and efficient flame retardant properties. In addition, the flame retardant modifier molecules also contain organic boron flame retardant components. Organic boron is a condensed phase flame retardant. When burned, it will generate boric anhydride or boric acid, and when thermally cracked, it will form a glassy molten covering to hinder the overflow of combustible gases. In addition, the boric acid structure will form a boron oxygen six-ring network structure when heated, further After the first step of heating, a BOC carbon layer is formed to cover the surface of the epoxy resin, reducing heat transfer, 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, which 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] The copper wire is used as the conductor, high-density polyethylene is extruded on the conductor to form an insulating layer, a copper tape is wrapped around the surface of the insulating 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 material of the protective sheath of the cable prepared by the present invention is based on high-density polyethylene, 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 obtained 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0034] Embodiment 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 for 6 h under vacuum. After the reaction is completed, 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 warm 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 (the 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;

[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 device on a heating mantle, gradually increase the temperature to 60°C, and react for 5 hours with continuous stirring during the reaction. After the reaction is completed, remove the solvent by distillation under reduced pressure, wash with deionized water, and dry in an oven to obtain a flame retardant modifier.

[0039] Embodiment 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 for 6 h under vacuum. After the reaction is completed, cool to room temperature, filter, evaporate, and crystallize to obtain intermediate 1.

[0042] A2, 54.6g of intermediate product 1, 31.4g of n-decylamine, 30mL of triethylamine and 200mL 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 warm 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 (the 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. Place 27.6 g of 4-hydroxyphenylboric acid and 240 mL of N,N-dimethylformamide in a three-necked flask, stir in an ice bath at 5°C, and add 20 mL of triethylamine and 77.0 g of intermediate 2 in sequence. Place the device on a heating mantle, gradually increase the temperature to 60°C, and react for 5 hours with continuous stirring during the reaction. After the reaction is completed, remove the solvent by distillation under reduced pressure, wash with deionized water, and dry in an oven to obtain a flame retardant modifier.

[0044] Embodiment 3

[0045] Preparation of protective cover materials:

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

[0047] Embodiment 4

[0048] Preparation of protective cover materials:

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

[0050] Embodiment 5

[0051] Preparation of protective cover materials:

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

[0053] Embodiment 6

[0054] Copper wire is used as a conductor, high-density polyethylene is extruded on the conductor to form an insulating layer, and a copper tape is wrapped around the surface of the insulating layer to form a metal shielding layer. Then 80g of high-density polyethylene, 6g of glass fiber, 14g of the flame retardant modifier prepared in Example 1 and 5g of antioxidant 1010 are dried; the dried polycarbonate resin is stirred in a high-speed mixer at a speed of 400rpm for 5min, and then the glass fiber, flame retardant modifier, antioxidant 1010 and 5g of calcium stearate are added. After continuing to stir for 5min, the obtained mixture is sent to a twin-screw extruder at a speed of 300 rpm, melt blended, 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] Embodiments 3, 4, 5, and comparative examples 1 and 2 were made into corresponding shapes to be tested according to different test standards, and the following performance tests were performed:

[0060] The tensile properties are 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 national standard GB / T 2406 "Test method for combustion performance of plastics" is used to determine the limiting oxygen index of the sample;

[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 Embodiment 3 Embodiment 4 Embodiment 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] It can be seen from the above table that 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] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[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 specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A halogen-free low-smoke insulated cable, comprising a protective sheath, a metal shielding layer, an insulating layer and a conductor from the outside to the inside, characterized in that: The material of the protective cover comprises 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.

2. A halogen-free low-smoke insulated cable according to claim 1, characterized in that: 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 for 6 hours under vacuum. After the reaction is completed, cool to room temperature, filter, evaporate, and crystallize to obtain intermediate 1. A2, the intermediate product 1, n-decylamine, triethylamine and tetrahydrofuran were mixed and stirred in a three-necked flask, and then the device was placed on a heating mantle, and the reaction was kept at 56° C. for 6 hours. After the reaction was completed, the intermediate product 2 was obtained by filtration, rotary evaporation, column chromatography purification, and rotary evaporation. A3. Place 4-hydroxyphenylboric acid and N,N-dimethylformamide in a three-necked flask, stir in an ice bath at 5°C, and add triethylamine and intermediate 2 in sequence. Place the device on a heating mantle, and react at 60°C for 5 hours with continuous stirring during the reaction. After the reaction is completed, perform vacuum distillation, wash with ionized water, and dry in an oven to obtain a flame retardant modifier.

3. A halogen-free low-smoke insulated cable according to claim 2, characterized in that: In step A1, the ratio of toluene, phosphorus trichloride and pentaerythritol is 100 mL: 27.2 g: 13.6 g.

4. A halogen-free low-smoke insulated cable according to claim 2, characterized in that: In step A2, the ratio of the amount of intermediate product 1, n-decylamine, triethylamine and tetrahydrofuran is 27.3 g:15.7 g:15 mL:100 mL.

5. The halogen-free low-smoke insulated cable according to claim 2, characterized in that: In step A3, the ratio of 4-hydroxyphenylboric acid, N,N-dimethylformamide, triethylamine and intermediate 2 is 13.8 g: 120 mL: 10 mL: 38.5 g.

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

7. 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.

8. The method for preparing a halogen-free low-smoke insulated cable according to claim 1, characterized in that: The following steps are involved: The copper wire is used as the conductor, high-density polyethylene is extruded on the conductor to form an insulating layer, a copper tape is wrapped around the surface of the insulating 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.

Images