Manufacturing process of physically foamed polyethylene insulated cable

Abstract

The invention discloses a manufacturing process of a physically foamed polyethylene insulated cable, and belongs to the technical field of cable preparation. The manufacturing process of the physically foamed polyethylene insulated cable comprises the following steps: step 1, twisting multiple strands of copper, and cleaning to obtain a conductor material; 2, adding polyethylene resin, nano silicon dioxide, a free radical trapping agent, a performance additive and an antioxidant 1010 into a high-speed mixer, then adding calcium stearate to obtain a mixture, and carrying out melt plasticizing, injection of a physical foaming agent, extrusion and cooling on the mixture to obtain an insulating layer material; and 3, tightly wrapping the insulating layer material on the surface of the conductor material, then wrapping the insulating layer material with an aluminum foil, then wrapping the insulating layer material with a polyurethane material, winding a metal steel wire on the outer layer of the polyurethane material, and carrying out laser engraving to obtain the physically foamed polyethylene insulated cable. The cable prepared by the method has excellent aging resistance, thermal stability, mechanical property and insulating property.

Description

Technical Field

[0001] The invention belongs to the technical field of cable preparation, and in particular relates to a manufacturing process of a physically foamed polyethylene insulated cable. Background Art

[0002] With the rapid development of communication technology, power transmission, data transmission and other fields, the performance requirements for cables are becoming increasingly stringent, especially in terms of signal transmission efficiency, attenuation control, temperature resistance, mechanical strength and environmental protection. Traditional cable insulation materials, such as chemical foaming materials or solid insulation materials, have gradually exposed their limitations in response to these challenges and are unable to meet the needs of modern industry for high performance, high reliability and green environmental protection. Therefore, physical foaming polyethylene insulated cables have emerged as an innovative solution and have quickly become a hot topic in industry research.

[0003] Physical foaming polyethylene insulated cables use physical foaming technology to form a uniform cell structure by injecting gas into polyethylene resin. This unique structure gives the cable many excellent performance advantages. First of all, physical foaming polyethylene has an extremely low dielectric constant and dielectric loss tangent, which can significantly reduce the attenuation during signal transmission and improve transmission efficiency. This is especially important for high-frequency signal transmission. For example, in mobile communications, CATV coaxial cables, and railway digital signal cables, it can effectively ensure the stability and accuracy of the signal. Secondly, the uniformity of the cell structure makes the electrical performance of the cable more stable, and it can maintain a low attenuation change rate during long-term use, extending the service life of the cable.

[0004] Patent CN211319795U discloses a high-density polyvinyl chloride insulated cable, comprising a plurality of conductor cores, the outer walls of the plurality of conductor cores are wrapped with an insulating coating layer, the outer wall of the insulating coating layer is bonded with a shielding layer, the outer wall of the shielding layer is bonded with a waterproof and fireproof layer, the outer wall of the waterproof and fireproof layer is bonded with a jacket, the waterproof and fireproof layer is a composite material of polyethylene foam and polyphenylene sulfide, the outer wall of the conductor core is bonded with an insulating layer, and the jacket made of high-density polyvinyl chloride material can maximize the protection of the internal structure of the cable, improve the wear resistance, waterproof and fire resistance and corrosion resistance of the cable, etc. However, the aging resistance, thermal stability, mechanical properties and insulation properties of the cable prepared by this method still have room for improvement. Summary of the invention

[0005] The object of the present invention is to provide a manufacturing process of a physically foamed polyethylene insulated cable, which is used to solve the technical problems of poor aging resistance, thermal stability, mechanical properties and insulation properties of the cable in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a manufacturing process of a physically foamed polyethylene insulated cable, comprising the following steps: Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material; Step 2: Add polyethylene resin, nano-silica, free radical scavenger, modification aid and antioxidant 1010 into a high-speed mixer for premixing, then add calcium stearate, continue stirring and mixing to obtain a mixture, add the mixture into a twin-screw extruder, melt and plasticize, inject a physical foaming agent at the same time, extrude, and cool to obtain an insulating layer material; Step 3: Wrap the insulating layer material tightly on the surface of the conductor material, then wrap the aluminum foil on the outer layer of the insulating layer through a longitudinal wrapping machine, and then wrap a layer of polyurethane material, use an armoring machine to wrap the metal steel wire on the outer layer of the polyurethane material, and laser engrave it to obtain a physically foamed polyethylene insulated cable.

[0007] Preferably, in step 2, the polyethylene resin is prepared by mixing high-density polyethylene and low-density polyethylene in a mass ratio of 4:1, and the dosage ratio of the polyethylene resin, nano-silicon dioxide, free radical scavenger, modification aid, antioxidant 1010 and calcium stearate is (70-85) g: (10-15) g: (0.2-0.5) g: (1-3) g: (0.2-0.3) g: (0.5-1) g.

[0008] Preferably, the method for preparing the free radical scavenger comprises the following steps: Q1: Add p-hydroxyacetophenone to a reaction vessel, then add 2-(tert-butyl)isonicotinaldehyde and sodium hydroxide aqueous solution, stir at room temperature for reaction, and after the reaction is completed, pour into distilled water, adjust the pH, and filter to obtain intermediate 1; Q2: Add 4-chloroquinazoline and potassium carbonate to a container containing acetonitrile, stir, then add methyl 4-piperidinate, heat under reflux for reaction, and after the reaction is completed, filter to obtain intermediate 2; Q3: Add intermediate 2 to a container filled with distilled water, stir, then add sodium hydroxide, heat, stir and reflux for reaction. After the reaction is completed, cool, adjust the pH, extract, dry and purify to obtain intermediate 3; Q4: Add intermediate 3 to a container, and then add dichloromethane, EDC hydrochloride, 1-hydroxybenzotriazole and N,N-diisopropylethylamine in sequence, stir to react, then add intermediate 1, stir to react at room temperature, wash, spin dry, purify, and obtain a free radical scavenger.

[0009] In the above process, the synthesis reaction formula of the free radical scavenger is as follows:

[0010] The results of mass spectrometry analysis of intermediate 1 were: m / z: 281.14 (100.0%), 282.14 (19.8%), 283.15 (2.3%); the results of mass spectrometry analysis of intermediate 2 were: m / z: 271.13 (100.0%), 272.14 (16.5%), 273.14 (1.7%), 272.13 (1.1%); the results of mass spectrometry analysis of intermediate 3 were: m / z: 257.12 (100.0%), 258.12 (15.4%), 259.12 (1.7%), 258.11 (1.1%); the results of mass spectrometry analysis of free radical scavenger were: m / z: 520.25 (100.0%), 521.25 (35.1%), 522.25 (6.9%), 521.24 (1.5%).

[0011] Preferably, in Q1, the dosage ratio of p-hydroxyacetophenone, 2-(tert-butyl)isonicotinaldehyde and sodium hydroxide aqueous solution is (2-4) g: (3.81-4.03) g: (20-30) mL, the mass fraction of sodium hydroxide aqueous solution is 20 wt %, the stirring reaction time is 10-12 h, and the pH is adjusted to 5.8-6.2.

[0012] Preferably, in Q2, the dosage ratio of 4-chloroquinazoline, potassium carbonate, acetonitrile and methyl 4-piperidinic acid is (2.12-2.64) g: (1.12-1.68) g: (30-40) mL: (1.21-1.65) mL, the stirring time is 30-45 min, and the heating reflux reaction time is 5-7 h.

[0013] Preferably, in Q3, the amount ratio of intermediate 2, distilled water and sodium hydroxide is (2.3-3.4) g: (50-75) mL: (7-12) g, the heating stirring reflux reaction temperature is 90-110°C, and the reaction time is 4-12 h; in Q4, the amount ratio of intermediate 3, dichloromethane, EDC hydrochloride, 1-hydroxybenzotriazole, N,N-diisopropylethylamine and intermediate 1 is (0.12-0.18) g: (10-14) mL: (0.101-0.136) g: (0.094-0.11) g: (0.38-0.42) mL: (0.14-0.164) g, the stirring reaction time is 30-45 min, and the stirring reaction time at room temperature is 3-6 h.

[0014] Preferably, the preparation method of the modification aid comprises the following steps: S1: adding p-trifluoromethylaniline to a container filled with concentrated hydrochloric acid, stirring to dissolve, then dropping sodium nitrite aqueous solution to react, then dropping phenol dissolved in sodium hydroxide solution to react, stirring to react, after the reaction is completed, suction filtering, washing, recrystallization, and vacuum drying to obtain product A; S2: Add epichlorohydrin, cyclohexane and tetrabutylammonium bromide into a container, heat in an oil bath for reaction, slowly drop a mixture of product A and sodium hydroxide aqueous solution into the container, heat in an oil bath with stirring and reflux, and after the reflux is completed, rotary evaporate to obtain product B; S3: Add polytetrahydrofuran to a container containing dichloromethane, stir and dissolve under a nitrogen atmosphere, add boron trifluoride ether complex after cooling, continue stirring, add product B to dichloromethane, stir and add dropwise to the container, after the addition is complete, stir and react at low temperature, adjust the pH, separate the liquids, wash, and dry to obtain a modified auxiliary agent.

[0015] In the above process, the synthetic reaction formula of the modified additive is as follows:

[0016] The results of mass spectrometry analysis of product A were: m / z: 266.07 (100.0%), 267.07 (14.2%), 268.07(1.2%); the results of mass spectrometry analysis of product B were: m / z: 322.09 (100.0%), 323.10 (17.5%), 324.10(1.9%).

[0017] Preferably, in S1, the amount ratio of trifluoromethylaniline, concentrated hydrochloric acid, sodium nitrite aqueous solution, sodium hydroxide solution and phenol is (10.1-16.5) g: (45-55) mL: (35-45) mL: (12-16) mL: (8-10.7) g, the mass fraction of the sodium nitrite aqueous solution is 25wt%, the temperature for dripping the sodium nitrite aqueous solution is 0-5°C, the reaction time is 30-45min, the temperature for dripping the sodium hydroxide solution containing phenol is 0-10°C, the stirring reaction time is 2-4h, the mixture is washed with distilled water, and recrystallized with methanol.

[0018] Preferably, in S2, the dosage ratio of epichlorohydrin, cyclohexane, tetrabutylammonium bromide, product A and sodium hydroxide aqueous solution is (50-56.5) g: (45-56) mL: (0.42-0.55) g: (24.46-28.85) g: (20-25) mL, the oil bath heating reaction temperature is 100-105°C, the oil bath heating stirring reflux temperature is 98-106°C, and the reflux time is 6-8h.

[0019] Preferably, in S3, the dosage ratio of polytetrahydrofuran, boron trifluoride ether complex and product B is (2-3.4) g: (0.3-0.36) g: (1.24-1.68) g, the stirring time is continued for 30-45 min, the low-temperature stirring reaction temperature is 0-1°C, and the reaction time is 20-25 h.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention first uses p-hydroxyacetophenone, 2-(tert-butyl)isonicotinaldehyde, 4-chloroquinazoline, 4-piperidinic acid methyl ester and 1-hydroxybenzotriazole as main raw materials to prepare a free radical scavenger, and then uses p-trifluoromethylaniline, epichlorohydrin and polytetrahydrofuran as main raw materials to prepare a modification auxiliary agent. The free radical scavenger and the modification auxiliary agent are added to the preparation process of the cable, which can effectively improve its aging resistance, thermal stability, mechanical properties and insulation properties.

[0021] 2. The free radical scavenger prepared in the present invention is added into the preparation process of the physically foamed polyethylene insulated cable, which can effectively improve the aging resistance and thermal stability of the cable.

[0022] 3. The modified auxiliary agent prepared in the present invention is added into the preparation process of the physically foamed polyethylene insulated cable, which can effectively improve the mechanical properties, insulation properties and aging resistance of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is a cross-sectional schematic diagram of the physically foamed polyethylene insulated cable prepared by the present invention.

[0025] Description of the drawings: 1. Conductor; 2. Insulation layer; 3. Aluminum foil layer; 4. Polyurethane layer; 5. Metal steel wire layer. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in 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.

[0027] Example 1: See Figure 1 As shown, a physically foamed polyethylene insulated cable of the present embodiment comprises a conductor 1, an insulating layer 2, an aluminum foil layer 3, a polyurethane layer 4 and a metal steel wire layer 5 which are sequentially arranged from the inside to the outside. The conductor is provided with a plurality of conductors, preferably seven, which are formed by tightly combining an inner one and six outer annular arrays. The outer periphery of the conductor 1 is uniformly wrapped with an insulating layer 2, an aluminum foil layer 3 is wrapped on the outer side of the insulating layer 2, a polyurethane layer 4 is wrapped on the outer side of the aluminum foil layer 3, and a metal steel wire layer 5 is wrapped on the outer side of the polyurethane layer 4.

[0028] Example 2: This example discloses a method for preparing a free radical scavenger, comprising the following steps: Q1: 3 g of p-hydroxyacetophenone was added to a reaction vessel, followed by 3.92 g of 2-(tert-butyl)isonicotinaldehyde and 25 mL of a 20 wt% sodium hydroxide aqueous solution, and the mixture was stirred at room temperature for 12 h. After the reaction, the mixture was poured into distilled water, the pH was adjusted to 6.2, and the mixture was filtered to obtain intermediate 1. Q2: Add 2.38 g of 4-chloroquinazoline and 1.4 g of potassium carbonate to a container containing 35 mL of acetonitrile, stir for 30 min, then add 1.43 mL of methyl 4-piperidinylcarboxylate, heat under reflux for 6 h, and after the reaction is completed, filter to obtain intermediate 2; Q3: Add 2.8 g of intermediate 2 to a container containing 62.5 mL of distilled water, stir, then add 9.5 g of sodium hydroxide, heat and stir under reflux at 100 °C for 12 h, after the reaction is completed, cool, adjust pH to 7, extract, dry, and purify to obtain intermediate 3; Q4: 0.15 g of intermediate 3 was added to a container, and then 12 mL of dichloromethane, 0.118 g of EDC hydrochloride, 0.102 g of 1-hydroxybenzotriazole and 0.4 mL of N,N-diisopropylethylamine were added in sequence. After stirring for 45 min, 0.152 g of intermediate 1 was added. After stirring for 6 h at room temperature, the mixture was washed, spin-dried and purified to obtain a free radical scavenger.

[0029] This embodiment discloses a method for preparing a modification aid, comprising the following steps: S1: Add 13.3 g of p-trifluoromethylaniline to a container containing 50 mL of concentrated hydrochloric acid, stir to dissolve, then drop 40 mL of a 25 wt% sodium nitrite aqueous solution at 3°C, react for 30 min, then drop 9.3 g of phenol dissolved in 14 mL of sodium hydroxide solution at 5°C, stir to react for 4 h, and after the reaction is completed, filter, wash with distilled water, recrystallize with methanol, and vacuum dry to obtain product A; S2: 53.2 g of epichlorohydrin, 50 mL of cyclohexane and 0.47 g of tetrabutylammonium bromide were added to a container, heated in an oil bath at 100°C for reaction, a mixture of 26.17 g of product A and 22.5 mL of sodium hydroxide aqueous solution was slowly added dropwise to the container, heated in an oil bath at 102°C with stirring and refluxed for 8 h, and after the reflux was completed, rotary evaporation was performed to obtain product B; S3: Add 2.7g of polytetrahydrofuran to a container containing 10mL of dichloromethane, stir and dissolve under a nitrogen atmosphere, add 0.33g of boron trifluoride ether complex after cooling, continue stirring for 30min, add 1.44g of product B to 5mL of dichloromethane, stir and add dropwise to the container, after the addition is complete, react with stirring at 0℃ for 24h, adjust pH=7, separate the liquids, wash, and dry to obtain a modified auxiliary agent.

[0030] This embodiment discloses a manufacturing process of a physically foamed polyethylene insulated cable, comprising the following steps: Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material; Step 2: Add 77.5g of polyethylene resin (prepared by mixing high-density polyethylene and low-density polyethylene in a mass ratio of 4:1), 12.5g of nano-silicon dioxide, 0.35g of free radical scavenger, 2g of modification aid and 0.25g of antioxidant 1010 into a high-speed mixer for premixing, then add 0.75g of calcium stearate, continue stirring and mixing to obtain a mixture, add the mixture into a twin-screw extruder, melt and plasticize, inject a physical foaming agent at the same time, extrude, cool, and obtain an insulating layer material; Step 3: Wrap the insulating layer material tightly on the surface of the conductor material, then wrap the aluminum foil on the outer layer of the insulating layer through a longitudinal wrapping machine, and then wrap a layer of polyurethane material, use an armoring machine to wrap the metal steel wire on the outer layer of the polyurethane material, and laser engrave it to obtain a physically foamed polyethylene insulated cable.

[0031] Example 3: This example discloses a method for preparing a free radical scavenger, comprising the following steps: Q1: 2 g of p-hydroxyacetophenone was added to a reaction vessel, followed by 3.81 g of 2-(tert-butyl)isonicotinaldehyde and 20 mL of a 20 wt% sodium hydroxide aqueous solution, and the mixture was stirred at room temperature for 12 h. After the reaction, the mixture was poured into distilled water, the pH was adjusted to 6.2, and the mixture was filtered to obtain an intermediate 1. Q2: Add 2.12 g of 4-chloroquinazoline and 1.12 g of potassium carbonate to a container containing 40 mL of acetonitrile, stir for 30 min, then add 1.21 mL of methyl 4-piperidinylcarboxylate, heat under reflux for 6 h, and after the reaction is completed, filter to obtain intermediate 2; Q3: Add 2.3 g of intermediate 2 to a container filled with 50 mL of distilled water, stir, then add 7 g of sodium hydroxide, heat and stir under reflux at 100 °C for 12 h, after the reaction is completed, cool, adjust pH to 7, extract, dry, and purify to obtain intermediate 3; Q4: 0.12 g of intermediate 3 was added to a container, and then 14 mL of dichloromethane, 0.101 g of EDC hydrochloride, 0.094 g of 1-hydroxybenzotriazole and 0.38 mL of N,N-diisopropylethylamine were added in sequence. After stirring for 45 min, 0.14 g of intermediate 1 was added. After stirring for 6 h at room temperature, the mixture was washed, spin-dried and purified to obtain a free radical scavenger.

[0032] This embodiment discloses a method for preparing a modification aid, comprising the following steps: S1: Add 10.1 g of p-trifluoromethylaniline to a container containing 55 mL of concentrated hydrochloric acid, stir to dissolve, then drop 35 mL of a 25 wt% sodium nitrite aqueous solution at 3°C, react for 30 min, then drop 8 g of phenol dissolved in 12 mL of sodium hydroxide solution at 5°C, stir to react for 4 h, and after the reaction is completed, filter, wash with distilled water, recrystallize with methanol, and vacuum dry to obtain product A; S2: 50 g of epichlorohydrin, 45 mL of cyclohexane and 0.42 g of tetrabutylammonium bromide were added to a container, heated in an oil bath at 100°C for reaction, a mixture of 24.46 g of product A and 20 mL of sodium hydroxide aqueous solution was slowly added dropwise to the container, heated in an oil bath at 102°C with stirring and refluxed for 8 h, and after the reflux was completed, rotary evaporation was performed to obtain product B; S3: Add 2g of polytetrahydrofuran to a container containing 10mL of dichloromethane, stir and dissolve under a nitrogen atmosphere, add 0.36g of boron trifluoride ether complex after cooling, continue stirring for 30min, add 1.24g of product B to 5mL of dichloromethane, stir and add dropwise to the container, after the addition is complete, react at 0℃ with stirring for 24h, adjust pH=7, separate the liquids, wash, and dry to obtain a modified auxiliary agent.

[0033] This embodiment discloses a manufacturing process of a physically foamed polyethylene insulated cable, comprising the following steps: Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material; Step 2: 70g of polyethylene resin (prepared by mixing high-density polyethylene and low-density polyethylene in a mass ratio of 4:1), 15g of nano-silicon dioxide, 0.2g of free radical scavenger, 1g of modification aid and 0.2g of antioxidant 1010 are added to a high-speed mixer for premixing, and then 0.5g of calcium stearate is added, and stirring and mixing are continued to obtain a mixture, and the mixture is added to a twin-screw extruder, melted and plasticized, and a physical foaming agent is injected at the same time, extruded, and cooled to obtain an insulating layer material; Step 3: Wrap the insulating layer material tightly on the surface of the conductor material, then wrap the aluminum foil on the outer layer of the insulating layer through a longitudinal wrapping machine, and then wrap a layer of polyurethane material, use an armoring machine to wrap the metal steel wire on the outer layer of the polyurethane material, and laser engrave it to obtain a physically foamed polyethylene insulated cable.

[0034] Example 4: This example discloses a method for preparing a free radical scavenger, comprising the following steps: Q1: 4 g of p-hydroxyacetophenone was added to a reaction vessel, followed by 4.03 g of 2-(tert-butyl)isonicotinaldehyde and 30 mL of a 20 wt% sodium hydroxide aqueous solution, and the mixture was stirred at room temperature for 12 h. After the reaction, the mixture was poured into distilled water, the pH was adjusted to 6.2, and the mixture was filtered to obtain an intermediate 1. Q2: Add 2.64 g 4-chloroquinazoline and 1.68 g potassium carbonate to a container containing 30 mL acetonitrile, stir for 30 min, then add 1.65 mL methyl 4-piperidinylcarboxylate, heat under reflux for 6 h, and after the reaction is completed, filter to obtain intermediate 2; Q3: Add 3.4 g of intermediate 2 to a container filled with 75 mL of distilled water, stir, then add 12 g of sodium hydroxide, heat and stir under reflux at 100°C for 12 h, after the reaction is completed, cool, adjust pH to 7, extract, dry, and purify to obtain intermediate 3; Q4: 0.18 g of intermediate 3 was added to a container, and then 10 mL of dichloromethane, 0.136 g of EDC hydrochloride, 0.11 g of 1-hydroxybenzotriazole and 0.42 mL of N,N-diisopropylethylamine were added in sequence. After stirring for 45 min, 0.164 g of intermediate 1 was added. After stirring for 6 h at room temperature, the mixture was washed, spin-dried and purified to obtain a free radical scavenger.

[0035] This embodiment discloses a method for preparing a modification aid, comprising the following steps: S1: Add 16.5 g of p-trifluoromethylaniline to a container containing 45 mL of concentrated hydrochloric acid, stir to dissolve, then drop 45 mL of a 25 wt% sodium nitrite aqueous solution at 3°C, react for 30 min, then drop 10.7 g of phenol dissolved in 16 mL of sodium hydroxide solution at 5°C, stir to react for 4 h, and after the reaction is completed, filter, wash with distilled water, recrystallize with methanol, and vacuum dry to obtain product A; S2: Add 56.5 g of epichlorohydrin, 56 mL of cyclohexane and 0.55 g of tetrabutylammonium bromide into a container, heat in an oil bath at 100°C for reaction, slowly drop a mixture of 28.85 g of product A and 25 mL of sodium hydroxide aqueous solution into the container, heat in an oil bath at 102°C with stirring and reflux for 8 h, and after the reflux is completed, rotary evaporate to obtain product B; S3: Add 3.4 g of polytetrahydrofuran to a container containing 10 mL of dichloromethane, stir and dissolve under a nitrogen atmosphere, add 0.3 g of boron trifluoride ether complex after cooling, continue stirring for 30 min, add 1.68 g of product B to 5 mL of dichloromethane, stir and add dropwise to the container, after the addition is complete, react at 0°C with stirring for 24 h, adjust the pH to 7, separate the liquids, wash, and dry to obtain a modified auxiliary agent.

[0036] This embodiment discloses a manufacturing process of a physically foamed polyethylene insulated cable, comprising the following steps: Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material; Step 2: 85g of polyethylene resin (prepared by mixing high-density polyethylene and low-density polyethylene in a mass ratio of 4:1), 10g of nano-silicon dioxide, 0.5g of free radical scavenger, 3g of modification aid and 0.3g of antioxidant 1010 are added to a high-speed mixer for premixing, and then 1g of calcium stearate is added, and stirring and mixing are continued to obtain a mixture, and the mixture is added to a twin-screw extruder, melted and plasticized, and a physical foaming agent is injected at the same time, extruded, and cooled to obtain an insulating layer material; Step 3: Wrap the insulating layer material tightly on the surface of the conductor material, then wrap the aluminum foil on the outer layer of the insulating layer through a longitudinal wrapping machine, and then wrap a layer of polyurethane material, use an armoring machine to wrap the metal steel wire on the outer layer of the polyurethane material, and laser engrave it to obtain a physically foamed polyethylene insulated cable.

[0037] Example 5: This example discloses a method for preparing a free radical scavenger, comprising the following steps: Q1: 2.5 g of p-hydroxyacetophenone was added to a reaction vessel, followed by 3.85 g of 2-(tert-butyl)isonicotinaldehyde and 22 mL of a 20 wt% sodium hydroxide aqueous solution, and the mixture was stirred at room temperature for 12 h. After the reaction, the mixture was poured into distilled water, the pH was adjusted to 6.2, and the mixture was filtered to obtain intermediate 1. Q2: Add 2.25 g of 4-chloroquinazoline and 1.31 g of potassium carbonate to a container containing 32 mL of acetonitrile, stir for 30 min, then add 1.33 mL of methyl 4-piperidinylcarboxylate, heat under reflux for 6 h, and after the reaction is completed, filter to obtain intermediate 2; Q3: Add 2.5 g of intermediate 2 to a container filled with 55 mL of distilled water, stir, then add 8 g of sodium hydroxide, heat and stir under reflux at 100 °C for 12 h, after the reaction is completed, cool, adjust pH to 7, extract, dry, and purify to obtain intermediate 3; Q4: 0.13 g of intermediate 3 was added to a container, and then 11 mL of dichloromethane, 0.109 g of EDC hydrochloride, 0.098 g of 1-hydroxybenzotriazole and 0.39 mL of N,N-diisopropylethylamine were added in sequence. After stirring for 45 min, 0.148 g of intermediate 1 was added. After stirring for 6 h at room temperature, the mixture was washed, spin-dried and purified to obtain a free radical scavenger.

[0038] This embodiment discloses a method for preparing a modification aid, comprising the following steps: S1: Add 11.9 g of p-trifluoromethylaniline to a container containing 48 mL of concentrated hydrochloric acid, stir to dissolve, then drop 38 mL of a 25 wt% sodium nitrite aqueous solution at 3°C, react for 30 min, then drop 8.5 g of phenol dissolved in 15 mL of sodium hydroxide solution at 5°C, stir to react for 4 h, and after the reaction is completed, filter, wash with distilled water, recrystallize with methanol, and vacuum dry to obtain product A; S2: 51.7 g of epichlorohydrin, 48 mL of cyclohexane and 0.45 g of tetrabutylammonium bromide were added to a container, heated in an oil bath at 100°C for reaction, a mixture of 25.23 g of product A and 21 mL of sodium hydroxide aqueous solution was slowly added dropwise to the container, heated in an oil bath at 102°C with stirring and refluxed for 8 h, and after the reflux was completed, rotary evaporation was performed to obtain product B; S3: Add 2.2g of polytetrahydrofuran to a container containing 10mL of dichloromethane, stir and dissolve under a nitrogen atmosphere, add 0.31g of boron trifluoride ether complex after cooling, continue stirring for 30min, add 1.31g of product B to 5mL of dichloromethane, stir and add dropwise to the container, after the addition is complete, react at 0℃ with stirring for 24h, adjust pH=7, separate the liquids, wash, and dry to obtain a modified auxiliary agent.

[0039] This embodiment discloses a manufacturing process of a physically foamed polyethylene insulated cable, comprising the following steps: Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material; Step 2: 72g of polyethylene resin (prepared by mixing high-density polyethylene and low-density polyethylene in a mass ratio of 4:1), 11g of nano-silicon dioxide, 0.3g of free radical scavenger, 1.5g of modification aid and 0.22g of antioxidant 1010 are added to a high-speed mixer for premixing, and then 0.6g of calcium stearate is added, and stirring and mixing are continued to obtain a mixture, and the mixture is added to a twin-screw extruder, melted and plasticized, and a physical foaming agent is injected at the same time, extruded, and cooled to obtain an insulating layer material; Step 3: Wrap the insulating layer material tightly on the surface of the conductor material, then wrap the aluminum foil on the outer layer of the insulating layer through a longitudinal wrapping machine, and then wrap a layer of polyurethane material, use an armoring machine to wrap the metal steel wire on the outer layer of the polyurethane material, and laser engrave it to obtain a physically foamed polyethylene insulated cable.

[0040] Comparative Example 1: Compared with Example 1, in the process of preparing the physically foamed polyethylene insulated cable in Comparative Example 1, no free radical scavenger is added, and other conditions remain unchanged.

[0041] Comparative Example 2: Compared with Example 1, in the process of preparing the physically foamed polyethylene insulated cable in Comparative Example 2, no modification aid is added, and other conditions remain unchanged.

[0042] Experimental Example: The performance of the physically foamed polyethylene insulated cables prepared in Examples 2-5 and Comparative Examples 1-2 was tested. The aging resistance of the samples was tested according to GB / T 2951.12-2008, the thermal stability of the samples was tested according to GB / T 2951.42-2008, the mechanical properties of the samples were tested according to GB / T 2951.11-2008, and the insulation properties of the samples were tested according to GB / T3048.5-2007. The test results are shown in Table 1: Table 1 project Tensile strength change rate / % Quality change rate / % Tensile strength / MPa Insulation resistance / MΩ·km Example 2 4.65 2.04 18.98 1114 Example 3 4.72 2.12 18.83 1102 Example 4 4.78 2.13 18.31 1105 Example 5 4.62 2.16 18.54 1108 Comparative Example 1 8.75 4.79 18.36 1098 Comparative Example 2 8.85 2.17 13.85 975 From the test results in Table 1, it can be seen that the physically foamed polyethylene insulated cables prepared in Examples 2-5 of the present invention have excellent aging resistance, thermal stability, mechanical properties and insulation properties. From the comparison between Comparative Example 1 and Examples 2-5, it can be seen that the addition of a free radical scavenger can effectively improve the aging resistance and thermal stability of the physically foamed polyethylene insulated cables; from the comparison between Comparative Example 2 and Examples 2-5, it can be seen that the addition of a modified auxiliary agent can effectively improve the mechanical properties, insulation properties and aging resistance of the physically foamed polyethylene insulated cables.

[0043] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0044] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A manufacturing process for a physically foamed polyethylene insulated cable, characterized in that: The following steps are involved: Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material; Step 2: Add polyethylene resin, nano-silica, free radical scavenger, modification aid and antioxidant 1010 into a high-speed mixer for premixing, then add calcium stearate, continue stirring and mixing to obtain a mixture, add the mixture into a twin-screw extruder, melt and plasticize, inject a physical foaming agent at the same time, extrude, and cool to obtain an insulating layer material; Step 3: Wrap the insulating layer material tightly on the surface of the conductor material, then wrap the aluminum foil on the outer layer of the insulating layer through a longitudinal wrapping machine, and then wrap a layer of polyurethane material, use an armoring machine to wrap the metal steel wire on the outer layer of the polyurethane material, and laser engrave it to obtain a physically foamed polyethylene insulated cable.

2. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 1, characterized in that: In the step 2, the polyethylene resin is prepared by mixing high-density polyethylene and low-density polyethylene in a mass ratio of 4:1, and the dosage ratio of the polyethylene resin, nano-silicon dioxide, free radical scavenger, modification aid, antioxidant 1010 and calcium stearate is (70-85) g: (10-15) g: (0.2-0.5) g: (1-3) g: (0.2-0.3) g: (0.5-1) g.

3. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 1, characterized in that: The preparation method of the free radical scavenger comprises the following steps: Q1: Add p-hydroxyacetophenone to a reaction vessel, then add 2-(tert-butyl)isonicotinaldehyde and sodium hydroxide aqueous solution, stir at room temperature for reaction, and after the reaction is completed, pour into distilled water, adjust the pH, and filter to obtain intermediate 1; Q2: Add 4-chloroquinazoline and potassium carbonate to a container containing acetonitrile, stir, then add methyl 4-piperidinate, heat under reflux for reaction, and after the reaction is completed, filter to obtain intermediate 2; Q3: Add intermediate 2 to a container filled with distilled water, stir, then add sodium hydroxide, heat, stir and reflux for reaction. After the reaction is completed, cool, adjust the pH, extract, dry and purify to obtain intermediate 3; Q4: Add intermediate 3 to a container, and then add dichloromethane, EDC hydrochloride, 1-hydroxybenzotriazole and N,N-diisopropylethylamine in sequence, stir to react, then add intermediate 1, stir to react at room temperature, wash, spin dry, purify, and obtain a free radical scavenger.

4. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 3, characterized in that: In the Q1, the dosage ratio of p-hydroxyacetophenone, 2-(tert-butyl)isonicotinaldehyde and sodium hydroxide aqueous solution is (2-4) g: (3.81-4.03) g: (20-30) mL.

5. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 3, characterized in that: In Q2, the usage ratio of 4-chloroquinazoline, potassium carbonate, acetonitrile and methyl 4-piperidinic acid ester is (2.12-2.64) g: (1.12-1.68) g: (30-40) mL: (1.21-1.65) mL.

6. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 3, characterized in that: In Q3, the usage ratio of intermediate 2, distilled water and sodium hydroxide is (2.3-3.4) g: (50-75) mL: (7-12) g; in Q4, the usage ratio of intermediate 3, dichloromethane, EDC hydrochloride, 1-hydroxybenzotriazole, N,N-diisopropylethylamine and intermediate 1 is (0.12-0.18) g: (10-14) mL: (0.101-0.136) g: (0.094-0.11) g: (0.38-0.42) mL: (0.14-0.164) g.

7. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 1, characterized in that: The preparation method of the modified auxiliary agent comprises the following steps: S1: adding p-trifluoromethylaniline to a container filled with concentrated hydrochloric acid, stirring to dissolve, then dropping sodium nitrite aqueous solution to react, then dropping phenol dissolved in sodium hydroxide solution to react, stirring to react, after the reaction is completed, suction filtering, washing, recrystallization, and vacuum drying to obtain product A; S2: Add epichlorohydrin, cyclohexane and tetrabutylammonium bromide into a container, heat in an oil bath for reaction, slowly drop a mixture of product A and sodium hydroxide aqueous solution into the container, heat in an oil bath with stirring and reflux, and after the reflux is completed, rotary evaporate to obtain product B; S3: Add polytetrahydrofuran to a container containing dichloromethane, stir and dissolve under a nitrogen atmosphere, add boron trifluoride ether complex after cooling, continue stirring, add product B to dichloromethane, stir and add dropwise to the container, after the addition is complete, stir and react at low temperature, adjust the pH, separate the liquids, wash, and dry to obtain a modified auxiliary agent.

8. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 7, characterized in that: In the S1, the usage ratio of trifluoromethylaniline, concentrated hydrochloric acid, sodium nitrite aqueous solution, sodium hydroxide solution and phenol is (10.1-16.5) g: (45-55) mL: (35-45) mL: (12-16) mL: (8-10.7) g.

9. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 7, characterized in that: In S2, the usage ratio of epichlorohydrin, cyclohexane, tetrabutylammonium bromide, product A and sodium hydroxide aqueous solution is (50-56.5) g: (45-56) mL: (0.42-0.55) g: (24.46-28.85) g: (20-25) mL.

10. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 7, characterized in that: In the S3, the usage ratio of polytetrahydrofuran, boron trifluoride ether complex and product B is (2-3.4) g: (0.3-0.36) g: (1.24-1.68) g.

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