A manufacturing process for physically foamed polyethylene insulated cable

Abstract

The present invention discloses a manufacturing process for a physically foamed polyethylene insulated cable, belonging to the technical field of cable preparation. The manufacturing process for the physically foamed polyethylene insulated cable comprises the following steps: Step 1: Twisting copper into multiple strands and cleaning to obtain a conductor material; Step 2: Adding polyethylene resin, nano-silica, a free radical scavenger, a modification aid, and an antioxidant 1010 to a high-speed mixer, followed by adding calcium stearate to obtain a mixture, melt-plasticizing the mixture, injecting a physical foaming agent, extruding, and cooling to obtain an insulating layer material; Step 3: Tightly wrapping the insulating layer material on the surface of the conductor material, then wrapping it with aluminum foil, then wrapping it with polyurethane material, winding a metal steel wire around the outer layer of the polyurethane material, and laser engraving to obtain a physically foamed polyethylene insulated cable. The cable prepared by this method has excellent aging resistance, thermal stability, mechanical properties, and insulation properties.

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 communications technology, power transmission, and data transmission, cable performance requirements are becoming increasingly stringent, particularly in terms of signal transmission efficiency, attenuation control, temperature resistance, mechanical strength, and environmental friendliness. Traditional cable insulation materials, such as chemical foam or solid insulation, are gradually exposing their limitations in meeting these challenges and are unable to meet modern industry's demand for high performance, high reliability, and environmental friendliness. Therefore, physically foamed polyethylene insulated cables have emerged as an innovative solution and have quickly become a hot topic in industry research.

[0003] Physically foamed polyethylene insulated cables utilize physical foaming technology, which creates a uniform cell structure by injecting gas into the polyethylene resin. This unique structure imparts numerous remarkable performance advantages to the cables. First, physically foamed polyethylene exhibits an extremely low dielectric constant and dielectric loss tangent, significantly reducing signal attenuation during transmission and improving transmission efficiency. This is particularly important for high-frequency signal transmission, such as in mobile communications, CATV coaxial cables, and railway digital signal cables, where it effectively ensures signal stability and accuracy. Second, the uniformity of the cell structure ensures more stable electrical performance, maintaining a low rate of change in attenuation over long-term use and extending the cable's service life.

[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 being wrapped with an insulating coating, the outer wall of the insulating coating being bonded with a shielding layer, the outer wall of the shielding layer being bonded with a waterproof and fireproof layer, the outer wall of the waterproof and fireproof layer being bonded with an outer jacket, the waterproof and fireproof layer being a composite material of polyethylene foam and polyphenylene sulfide, the outer wall of the conductor core being bonded with an insulating layer, and the outer jacket made of high-density polyvinyl chloride material being able to maximize the protection of the internal structure of the cable, and 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 purpose of the present invention is to provide a manufacturing process for a physically foamed polyethylene insulated cable, which is used to solve the technical problems of poor aging resistance, thermal stability, mechanical properties and insulation performance of cables in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a manufacturing process for a physically foamed polyethylene insulated cable, comprising the following steps:

[0008] Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material;

[0009] Step 2: Add polyethylene resin, nano-silica, free radical scavenger, modification aid and antioxidant 1010 to a high-speed mixer for premixing, then add calcium stearate, continue stirring and mixing to obtain a mixture, add the mixture to 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;

[0010] 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.

[0011] Preferably, 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-silica, 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.

[0012] Preferably, the method for preparing the free radical scavenger comprises the following steps:

[0013] Q1: Add p-hydroxyacetophenone to a reaction vessel, followed by 2-(tert-butyl)isonicotinaldehyde and a sodium hydroxide aqueous solution, and stir at room temperature. After the reaction is complete, pour into distilled water, adjust the pH, and filter to obtain intermediate 1;

[0014] Q2: Add 4-chloroquinazoline and potassium carbonate to a container containing acetonitrile, stir, then add methyl 4-piperidinate, heat under reflux for reaction, and filter after completion of the reaction to obtain intermediate 2;

[0015] Q3: Add intermediate 2 to a container filled with distilled water, stir, then add sodium hydroxide, heat and stir under reflux to react. After the reaction is completed, cool, adjust the pH, extract, dry, and purify to obtain intermediate 3;

[0016] Q4: Add intermediate 3 to a container, and then add dichloromethane, EDC hydrochloride, 1-hydroxybenzotriazole and N,N-diisopropylethylamine in sequence. After stirring for reaction, add intermediate 1. After stirring for reaction at room temperature, wash, spin dry, and purify to obtain a free radical scavenger.

[0017] In the above process, the synthesis reaction formula of the free radical scavenger is as follows:

[0018]

[0019] 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%).

[0020] 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 the 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.

[0021] Preferably, in Q2, the dosage ratio of 4-chloroquinazoline, potassium carbonate, acetonitrile and methyl 4-piperidinate 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.

[0022] 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 and 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.

[0023] Preferably, the preparation method of the modification aid comprises the following steps:

[0024] S1: p-Trifluoromethylaniline is added to a container containing concentrated hydrochloric acid, stirred to dissolve, and then a sodium nitrite aqueous solution is added dropwise to react. Phenol dissolved in a sodium hydroxide solution is then added dropwise to react with stirring. After the reaction is completed, the mixture is filtered, washed, recrystallized, and dried in vacuo to obtain product A.

[0025] S2: Add epichlorohydrin, cyclohexane and tetrabutylammonium bromide to a container, heat in an oil bath for reaction, slowly add a mixture of product A and sodium hydroxide aqueous solution dropwise to the container, heat in an oil bath with stirring and reflux, and after reflux, rotary evaporate to obtain product B;

[0026] S3: Add polytetrahydrofuran to a container filled with 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.

[0027] In the above process, the synthetic reaction formula of the modified additive is as follows:

[0028]

[0029] 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%).

[0030] Preferably, in S1, the amount ratio of p-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 25 wt%, the temperature for dropwise addition of the sodium nitrite aqueous solution is 0-5 ° C, the reaction time is 30-45 min, the temperature for dropwise addition of the sodium hydroxide solution containing phenol is 0-10 ° C, the stirring reaction time is 2-4 h, the reaction is washed with distilled water, and recrystallized with methanol.

[0031] 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.

[0032] Preferably, in 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, 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.

[0033] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0034] 1. The present invention first uses p-hydroxyacetophenone, 2-(tert-butyl)isonicotinaldehyde, 4-chloroquinazoline, methyl 4-piperidinate 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. Adding the free radical scavenger and the modification auxiliary agent to the preparation process of the cable can effectively improve its aging resistance, thermal stability, mechanical properties and insulation properties.

[0035] 2. The free radical scavenger prepared in the present invention is added to the preparation process of the physically foamed polyethylene insulated cable, which can effectively improve the aging resistance and thermal stability of the cable.

[0036] 3. The modified additive prepared in the present invention is added to 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

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0038] Figure 1 It is a cross-sectional schematic diagram of the physically foamed polyethylene insulated cable prepared by the present invention.

[0039] Description of the drawings: 1. Conductor; 2. Insulation layer; 3. Aluminum foil layer; 4. Polyurethane layer; 5. Metal steel wire layer. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0041] Example 1: See Figure 1 As shown, a physically foamed polyethylene insulated cable of this embodiment includes a conductor 1, an insulating layer 2, an aluminum foil layer 3, a polyurethane layer 4 and a metal steel wire layer 5 arranged in sequence from the inside to the outside. The conductor is provided with multiple conductors, preferably seven, and the seven conductors are tightly combined by one inner conductor and six outer ring arrays. The outer periphery of the conductor 1 is evenly wrapped with an insulating layer 2, the outer side of the insulating layer 2 is wrapped with an aluminum foil layer 3, the outer side of the aluminum foil layer 3 is wrapped with a polyurethane layer 4, and the outer side of the polyurethane layer 4 is wrapped with a metal steel wire layer 5.

[0042] Example 2: This example discloses a method for preparing a free radical scavenger, comprising the following steps:

[0043] 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. 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.

[0044] Q2: 2.38 g of 4-chloroquinazoline and 1.4 g of potassium carbonate were added to a container containing 35 mL of acetonitrile and stirred for 30 min. Then, 1.43 mL of methyl 4-piperidinate was added and the mixture was heated under reflux for 6 h. After the reaction was completed, the mixture was filtered to obtain intermediate 2.

[0045] Q3: Add 2.8 g of intermediate 2 to a container filled with 62.5 mL of distilled water and stir. Then add 9.5 g of sodium hydroxide and heat at 100°C with stirring under reflux for 12 h. After the reaction is complete, cool and adjust the pH to 7. Extract, dry, and purify to obtain intermediate 3.

[0046] Q4: 0.15 g of intermediate 3 was added to a container, followed by the addition of 12 mL of dichloromethane, 0.118 g of EDC hydrochloride, 0.102 g of 1-hydroxybenzotriazole, and 0.4 mL of N,N-diisopropylethylamine. After stirring for 45 minutes, 0.152 g of intermediate 1 was added, and the mixture was stirred at room temperature for 6 hours. The mixture was then washed, dried, and purified to obtain a free radical scavenger.

[0047] This embodiment discloses a method for preparing a modification aid, comprising the following steps:

[0048] S1: Add 13.3 g of p-trifluoromethylaniline to a container containing 50 mL of concentrated hydrochloric acid, stir and dissolve, then add dropwise 40 mL of a 25 wt% sodium nitrite aqueous solution at 3°C ​​and react for 30 min. Then, add dropwise 9.3 g of phenol dissolved in 14 mL of sodium hydroxide solution at 5°C and stir and react for 4 h. After the reaction is complete, filter, wash with distilled water, recrystallize with methanol, and dry in vacuo to obtain product A.

[0049] S2: Add 53.2 g of epichlorohydrin, 50 mL of cyclohexane, and 0.47 g of tetrabutylammonium bromide to a container, heat in an oil bath at 100°C for reaction, slowly add a mixture of 26.17 g of product A and 22.5 mL of sodium hydroxide aqueous solution to the container dropwise, heat in an oil bath at 102°C with stirring and reflux for 8 h, and after reflux, rotary evaporation to obtain product B;

[0050] S3: Add 2.7 g of polytetrahydrofuran to a container containing 10 mL of dichloromethane, stir and dissolve under a nitrogen atmosphere, cool, add 0.33 g of boron trifluoride ether complex, continue stirring for 30 minutes, add 1.44 g of product B to 5 mL of dichloromethane, stir and add dropwise to the container, after completion of the addition, stir and react at 0°C for 24 hours, adjust the pH to 7, separate the liquids, wash, and dry to obtain the modified auxiliary agent.

[0051] This embodiment discloses a manufacturing process for a physically foamed polyethylene insulated cable, comprising the following steps:

[0052] Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material;

[0053] Step 2: 77.5 g of polyethylene resin (prepared by mixing high-density polyethylene and low-density polyethylene in a mass ratio of 4:1), 12.5 g of nano-silica, 0.35 g of a free radical scavenger, 2 g of a modification aid, and 0.25 g of an antioxidant 1010 were added to a high-speed mixer for premixing, followed by adding 0.75 g of calcium stearate and continuing to stir and mix to obtain a mixture, which was added to a twin-screw extruder for melt plasticization, while injecting a physical foaming agent, extruding, and cooling to obtain an insulating layer material;

[0054] 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.

[0055] Example 3: This example discloses a method for preparing a free radical scavenger, comprising the following steps:

[0056] 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. 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.

[0057] Q2: Add 2.12 g of 4-chloroquinazoline and 1.12 g of potassium carbonate to a container containing 40 mL of acetonitrile and stir for 30 min. Then add 1.21 mL of methyl 4-piperidinate and heat under reflux for 6 h. After the reaction is complete, filter and obtain intermediate 2.

[0058] Q3: Add 2.3 g of intermediate 2 to a container filled with 50 mL of distilled water and stir. Then add 7 g of sodium hydroxide and heat at 100°C with stirring under reflux for 12 h. After the reaction is complete, cool and adjust the pH to 7. Extract, dry, and purify to obtain intermediate 3.

[0059] Q4: 0.12 g of intermediate 3 was added to a container, followed by the addition of 14 mL of dichloromethane, 0.101 g of EDC hydrochloride, 0.094 g of 1-hydroxybenzotriazole, and 0.38 mL of N,N-diisopropylethylamine. After stirring for 45 minutes, 0.14 g of intermediate 1 was added, and the mixture was stirred at room temperature for 6 hours. The mixture was then washed, dried, and purified to obtain a free radical scavenger.

[0060] This embodiment discloses a method for preparing a modification aid, comprising the following steps:

[0061] S1: Add 10.1 g of p-trifluoromethylaniline to a container containing 55 mL of concentrated hydrochloric acid, stir and dissolve, then add dropwise 35 mL of a 25 wt% sodium nitrite aqueous solution at 3°C ​​and react for 30 min. Then, add dropwise 8 g of phenol dissolved in 12 mL of sodium hydroxide solution at 5°C and stir and react for 4 h. After the reaction is complete, filter, wash with distilled water, recrystallize with methanol, and dry in vacuo to obtain product A.

[0062] S2: Add 50 g of epichlorohydrin, 45 mL of cyclohexane, and 0.42 g of tetrabutylammonium bromide to a container, heat in an oil bath at 100°C for reaction, slowly add a mixture of 24.46 g of product A and 20 mL of sodium hydroxide aqueous solution to the container dropwise, heat in an oil bath at 102°C with stirring and reflux for 8 h, and after reflux, rotary evaporate to obtain product B;

[0063] S3: Add 2 g of polytetrahydrofuran to a container containing 10 mL of dichloromethane, stir and dissolve under a nitrogen atmosphere, cool, add 0.36 g of boron trifluoride ether complex, continue stirring for 30 minutes, add 1.24 g of product B to 5 mL of dichloromethane, stir and add dropwise to the container, after completion of the addition, stir and react at 0°C for 24 hours, adjust the pH to 7, separate the liquids, wash, and dry to obtain the modified auxiliary agent.

[0064] This embodiment discloses a manufacturing process for a physically foamed polyethylene insulated cable, comprising the following steps:

[0065] Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material;

[0066] Step 2: 70 g of polyethylene resin (prepared by mixing high-density polyethylene and low-density polyethylene in a mass ratio of 4:1), 15 g of nano-silica, 0.2 g of a free radical scavenger, 1 g of a modifying aid, and 0.2 g of an antioxidant 1010 are added to a high-speed mixer for premixing, followed by adding 0.5 g of calcium stearate and continuing to stir and mix to obtain a mixture, which is added to a twin-screw extruder for melt plasticization, while injecting a physical foaming agent, extruding, and cooling to obtain an insulating layer material;

[0067] 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.

[0068] Example 4: This example discloses a method for preparing a free radical scavenger, comprising the following steps:

[0069] 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. 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.

[0070] Q2: Add 2.64 g of 4-chloroquinazoline and 1.68 g of potassium carbonate to a container containing 30 mL of acetonitrile and stir for 30 min. Then add 1.65 mL of methyl 4-piperidinate and heat under reflux for 6 h. After the reaction is complete, filter and obtain intermediate 2.

[0071] Q3: Add 3.4 g of intermediate 2 to a container filled with 75 mL of distilled water and stir. Then add 12 g of sodium hydroxide and heat at 100°C with stirring under reflux for 12 h. After the reaction is complete, cool and adjust the pH to 7. Extract, dry, and purify to obtain intermediate 3.

[0072] Q4: 0.18 g of intermediate 3 was added to a container, followed by the addition of 10 mL of dichloromethane, 0.136 g of EDC hydrochloride, 0.11 g of 1-hydroxybenzotriazole, and 0.42 mL of N,N-diisopropylethylamine. After stirring for 45 minutes, 0.164 g of intermediate 1 was added, and the mixture was stirred at room temperature for 6 hours. The mixture was then washed, dried, and purified to obtain a free radical scavenger.

[0073] This embodiment discloses a method for preparing a modification aid, comprising the following steps:

[0074] S1: Add 16.5 g of p-trifluoromethylaniline to a container containing 45 mL of concentrated hydrochloric acid, stir and dissolve, then add dropwise 45 mL of a 25 wt% sodium nitrite aqueous solution at 3°C, react for 30 min, then add dropwise 10.7 g of phenol dissolved in 16 mL of sodium hydroxide solution at 5°C, stir and react for 4 h. After the reaction is complete, filter, wash with distilled water, recrystallize with methanol, and dry in vacuo to obtain product A;

[0075] S2: Add 56.5 g of epichlorohydrin, 56 mL of cyclohexane, and 0.55 g of tetrabutylammonium bromide to a container, heat in an oil bath at 100°C for reaction, slowly add a mixture of 28.85 g of product A and 25 mL of sodium hydroxide aqueous solution to the container dropwise, heat in an oil bath at 102°C with stirring and reflux for 8 h, and after reflux, rotary evaporation to obtain product B;

[0076] S3: Add 3.4 g of polytetrahydrofuran to a container containing 10 mL of dichloromethane, stir and dissolve under a nitrogen atmosphere, cool, add 0.3 g of boron trifluoride ether complex, continue stirring for 30 minutes, add 1.68 g of product B to 5 mL of dichloromethane, stir and add dropwise to the container, after completion of the addition, stir and react at 0°C for 24 hours, adjust the pH to 7, separate the liquids, wash, and dry to obtain the modified auxiliary agent.

[0077] This embodiment discloses a manufacturing process for a physically foamed polyethylene insulated cable, comprising the following steps:

[0078] Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material;

[0079] Step 2: 85 g of polyethylene resin (prepared by mixing high-density polyethylene and low-density polyethylene in a mass ratio of 4:1), 10 g of nano-silica, 0.5 g of a free radical scavenger, 3 g of a modification aid, and 0.3 g of an antioxidant 1010 are added to a high-speed mixer for premixing, followed by adding 1 g of calcium stearate and continuing to stir and mix to obtain a mixture, which is added to a twin-screw extruder for melt plasticization, while injecting a physical foaming agent, extruding, and cooling to obtain an insulating layer material;

[0080] 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.

[0081] Example 5: This example discloses a method for preparing a free radical scavenger, comprising the following steps:

[0082] 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. 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.

[0083] Q2: Add 2.25 g of 4-chloroquinazoline and 1.31 g of potassium carbonate to a container containing 32 mL of acetonitrile and stir for 30 min. Then add 1.33 mL of methyl 4-piperidinate and heat under reflux for 6 h. After the reaction is complete, filter and obtain intermediate 2.

[0084] Q3: Add 2.5 g of intermediate 2 to a container filled with 55 mL of distilled water and stir. Then add 8 g of sodium hydroxide and heat at 100°C with stirring under reflux for 12 h. After the reaction is complete, cool and adjust the pH to 7. Extract, dry, and purify to obtain intermediate 3.

[0085] Q4: 0.13 g of intermediate 3 was added to a container, followed by the addition of 11 mL of dichloromethane, 0.109 g of EDC hydrochloride, 0.098 g of 1-hydroxybenzotriazole, and 0.39 mL of N,N-diisopropylethylamine. After stirring for 45 minutes, 0.148 g of intermediate 1 was added, and the mixture was stirred at room temperature for 6 hours. The mixture was then washed, dried, and purified to obtain a free radical scavenger.

[0086] This embodiment discloses a method for preparing a modification aid, comprising the following steps:

[0087] S1: Add 11.9 g of p-trifluoromethylaniline to a container containing 48 mL of concentrated hydrochloric acid, stir and dissolve, then add dropwise 38 mL of a 25 wt% sodium nitrite aqueous solution at 3°C, react for 30 min, then add dropwise 8.5 g of phenol dissolved in 15 mL of sodium hydroxide solution at 5°C, stir and react for 4 h. After the reaction is complete, filter, wash with distilled water, recrystallize with methanol, and dry in vacuo to obtain product A;

[0088] S2: Add 51.7 g of epichlorohydrin, 48 mL of cyclohexane, and 0.45 g of tetrabutylammonium bromide to a container, heat in an oil bath at 100°C for reaction, slowly add a mixture of 25.23 g of product A and 21 mL of sodium hydroxide aqueous solution to the container dropwise, heat in an oil bath at 102°C with stirring and reflux for 8 h, and after reflux, rotary evaporation to obtain product B;

[0089] S3: Add 2.2 g of polytetrahydrofuran to a container containing 10 mL of dichloromethane, stir and dissolve under a nitrogen atmosphere, cool, add 0.31 g of boron trifluoride ether complex, continue stirring for 30 minutes, add 1.31 g of product B to 5 mL of dichloromethane, stir and add dropwise to the container, after completion of the addition, stir and react at 0°C for 24 hours, adjust the pH to 7, separate the liquids, wash, and dry to obtain the modified auxiliary agent.

[0090] This embodiment discloses a manufacturing process for a physically foamed polyethylene insulated cable, comprising the following steps:

[0091] Step 1: Twisting copper into multiple strands and then cleaning them to obtain conductor material;

[0092] Step 2: 72 g of polyethylene resin (prepared by mixing high-density polyethylene and low-density polyethylene in a mass ratio of 4:1), 11 g of nano-silica, 0.3 g of a free radical scavenger, 1.5 g of a modification aid, and 0.22 g of an antioxidant 1010 were added to a high-speed mixer for premixing, followed by adding 0.6 g of calcium stearate and continuing to stir and mix to obtain a mixture, which was added to a twin-screw extruder for melt plasticization, while injecting a physical foaming agent, extruding, and cooling to obtain an insulating layer material;

[0093] 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.

[0094] Comparative Example 1: Compared with Example 1, in Comparative Example 1, during the preparation of the physically foamed polyethylene insulated cable, no free radical scavenger was added, and other conditions remained unchanged.

[0095] Comparative Example 2: Compared with Example 1, in Comparative Example 2, during the process of preparing the physically foamed polyethylene insulated cable, no modifying agent was added, and other conditions remained unchanged.

[0096] 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:

[0097] Table 1

[0098] 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

[0099] The test results in Table 1 indicate that the physically foamed polyethylene insulated cables prepared in Examples 2-5 of the present invention exhibit excellent aging resistance, thermal stability, mechanical properties, and insulation performance. A comparison between Comparative Example 1 and Examples 2-5 demonstrates that the addition of a free radical scavenger effectively improves the aging resistance and thermal stability of the physically foamed polyethylene insulated cables. A comparison between Comparative Example 2 and Examples 2-5 demonstrates that the addition of a modification aid effectively improves the mechanical properties, insulation performance, and aging resistance of the physically foamed polyethylene insulated cables.

[0100] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0101] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. 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 to a high-speed mixer for premixing, then add calcium stearate, continue stirring and mixing to obtain a mixture, add the mixture to 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 insulation material tightly on the surface of the conductor material, then wrap the aluminum foil on the outer layer of the insulation 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; The preparation method of the free radical scavenger comprises the following steps: Q1: Add p-hydroxyacetophenone to a reaction vessel, followed by 2-(tert-butyl)isonicotinaldehyde and a sodium hydroxide aqueous solution, and stir at room temperature. After the reaction is complete, 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 filter after completion of the reaction to obtain intermediate 2; Q3: Add intermediate 2 to a container filled with distilled water, stir, then add sodium hydroxide, heat and stir under reflux to react. 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. After stirring for reaction, add intermediate 1. After stirring for reaction at room temperature, wash, spin dry, and purify to obtain a free radical scavenger.

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-silica, 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: In the Q1, the usage 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.

4. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 1, characterized in that: In the Q2, the usage ratio of 4-chloroquinazoline, potassium carbonate, acetonitrile and methyl 4-piperidinate is (2.12-2.64) g: (1.12-1.68) g: (30-40) mL: (1.21-1.65) mL.

5. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 1, 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.

6. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 1, characterized in that: The preparation method of the modification auxiliary agent comprises the following steps: S1: p-Trifluoromethylaniline is added to a container containing concentrated hydrochloric acid, stirred to dissolve, and then a sodium nitrite aqueous solution is added dropwise to react. Phenol dissolved in a sodium hydroxide solution is then added dropwise to react with stirring. After the reaction is completed, the mixture is filtered, washed, recrystallized, and dried in vacuo to obtain product A. S2: Add epichlorohydrin, cyclohexane and tetrabutylammonium bromide to a container, heat in an oil bath for reaction, slowly add a mixture of product A and sodium hydroxide aqueous solution dropwise to the container, heat in an oil bath with stirring and reflux, and after reflux, rotary evaporate to obtain product B; S3: Add polytetrahydrofuran to a container filled with 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.

7. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 6, characterized in that: In S1, the usage ratio of p-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.

8. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 6, 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.

9. The manufacturing process of a physically foamed polyethylene insulated cable according to claim 6, 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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