Wire and cable production process

Abstract

The invention relates to the technical field of wires and cables, and discloses a wire and cable production process, which comprises the following steps: S1, material blending: carrying out melt blending on high-density polyethylene particles, silicone rubber particles, ethylene propylene diene monomer particles and an antioxidant; adding an activating agent and an anti-pre-crosslinking agent; s2, vulcanization treatment: adding a dicumyl peroxide solution, carrying out vulcanization treatment, and then crushing into cross-linked plastic particles; s3, pilot production of the single-core cable: melting the cross-linked plastic particles and then coating the cross-linked plastic particles on the conductor; s4, performance testing: carrying out mechanical performance testing and insulating performance testing; and S5, cable core twisting: twisting a plurality of single-core cables together to form a complete wire cable. The wire cable prepared by the invention has relatively high resistance and deformation capability under the action of external force; and the influence on the tensile strength and the elongation at break in a high-temperature environment is small, the service life is effectively prolonged, and the fault rate of a circuit is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of electric wires and cables, and in particular to a production process of electric wires and cables. Background Art

[0002] Cross-linked polyethylene is the most commonly used high-voltage cable insulation material in the power industry worldwide. It uses cross-linking technology to change polyethylene from a linear chain polymer thermoplastic material to a thermosetting material with a three-dimensional network structure of cross-linked molecular chains. It has extremely excellent insulation and dielectric properties as well as good mechanical properties and chemical stability. Therefore, it is widely used in cable insulation layers.

[0003] A Chinese patent discloses a high-voltage cross-linked polyethylene insulated power cable and its preparation process (Announcement No. CN114334293A). The patented technology increases the types of cable models and improves the variety. The short-circuit current resistance and shielding effect of the cable are enhanced, and the electrical performance is better. However, its resistance and deformation capabilities under external forces are weak, and it is easy to age in high temperature environments. Summary of the invention

[0004] The object of the present invention is to provide a wire and cable production process to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A production process for electric wires and cables, comprising the following steps:

[0007] S1. Material blending: 80-90 parts of high-density polyethylene particles, 10-12 parts of silicone rubber particles, 10-12 parts of EPDM rubber particles and 0.2-0.3 parts of antioxidant are added into an internal mixer by mass, and melt blended for 5-8 minutes at a temperature of 135-145° C. and a rotation speed of 60-80 r / min; then 0.2-0.3 parts of activator and 0.2-0.3 parts of anti-pre-crosslinking agent are added to mix uniformly to obtain a blend;

[0008] S2, vulcanization treatment: adding 0.3-0.5 parts of dicumyl peroxide solution to the blend obtained in step S1, mixing evenly, adding to a flat vulcanizer for vulcanization treatment to obtain cross-linked flakes; and then crushing into cross-linked plastic particles;

[0009] S3. Single-core cable trial production: Preheat the cross-linked plastic particles to 80-90°C and add them into the extruder to melt under high temperature and high pressure; then extrude and coat them evenly on the preheated conductor to form an insulating layer on the conductor, and then degas the conductor to obtain the trial-produced single-core cable; the conductor can be copper wire or aluminum wire;

[0010] S4. Performance test: Conduct mechanical property test and insulation performance test on the insulation layer of the trial-produced single-core cable. Once it meets the design requirements, formal production can be carried out according to the trial production method;

[0011] S5. Cable core twisting: Twist multiple single-core cables produced formally together to form a multi-core cable, and then use an extruder to extrude the sheath on the outside of the multi-core cable to form a complete wire and cable.

[0012] As a further solution of the present invention: in the step S1,

[0013] The antioxidant is one or both of a compound of octadecyl beta-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite or a compound of pentaerythritol tetrakis[beta-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite;

[0014] The silicone rubber particles are one or both of methyl vinyl compound silicone rubber and methyl vinyl silicone rubber;

[0015] The activator is one or more of divinylbenzene, triallyl cyanurate, triallyl phosphate, and dimethacrylate;

[0016] The anti-pre-crosslinking agent is one or both of styrene and caprolactam.

[0017] As a further solution of the present invention: in the step S2, the dicumyl peroxide solution is prepared by mixing dicumyl peroxide powder and acetone in a mass ratio of 1:10.

[0018] As a further solution of the present invention: in the step S2, the mold temperature of the flat vulcanizer during the vulcanization treatment is 170-180°C, the pressure is 14-16 MPa, the vulcanization time is 10-12 minutes, and then cold pressing is performed for 8-10 minutes.

[0019] As a further solution of the present invention: in the step S3, the extrusion temperature of the extruder is 120-130°C, the extrusion pressure is 9-10 MPa; the preheating temperature of the conductor is 80-85°C.

[0020] As a further solution of the present invention: in the step S3, the degassing temperature is 65 to 75°C, and the degassing time is 7 to 14 days.

[0021] As a further solution of the present invention: in the step S4, the method for testing the mechanical properties of the insulation layer is as follows: take an insulation layer sample on a single-core cable, perform a tensile test on the sample, calculate the stress and strain, and draw a stress-strain curve of the sample; then obtain the tensile yield stress, elongation at break, tensile strength and elastic modulus of the sample material from the curve to determine whether it meets the design requirements; wherein the calculation formula for the stress and strain is as follows:

[0022]

[0023] In the above formulas (1) and (2), σ is stress, A is the cross-sectional area of ​​the specimen, p is the tensile force, ε is strain, l is the length of the specimen when it breaks, and l0 is the original length of the specimen.

[0024] The insulation performance test method of the insulation layer is as follows: heat the single-core cable from 20°C to 140°C at a heating rate of 10°C / min, keep it warm for one hour, and then test its insulation performance.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The invention firstly mixes high-density polyethylene particles, silicone rubber particles, EPDM rubber particles and parts of antioxidant, activator and anti-pre-crosslinking agent; then adds dicumyl peroxide solution for vulcanization treatment; then sequentially carries out single-core cable trial production, performance test and cable core twisting: twists a plurality of officially produced single-core cables together to form a multi-core cable, and then extrude a sheath on the outer side of the multi-core cable through an extruder to form a complete wire and cable; the wire and cable has strong resistance and deformation ability under the action of external force; and the tensile strength and elongation at break are less affected in a high temperature environment, effectively prolonging the service life and reducing the failure rate of the line. DETAILED DESCRIPTION

[0027] Example 1

[0028] In an embodiment of the present invention, a production process for electric wires and cables comprises the following steps:

[0029] S1. Add 80 parts of high-density polyethylene particles, 10 parts of methyl vinyl compounded silicone rubber, 10 parts of ethylene propylene rubber particles and 0.2 parts of a compound of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite into an internal mixer by mass, and melt-blend for 5 minutes at a temperature of 135° C. and a speed of 60 r / min; then add 0.2 parts of divinylbenzene and 0.2 parts of styrene, mix them evenly, and obtain a blend;

[0030] S2, vulcanization treatment: add 0.3 parts of a solution prepared by dicumyl peroxide powder and acetone at a ratio of 1:10 to the blend obtained in step S1, mix well, add to a flat vulcanizer, vulcanize for 10 minutes at a mold temperature of 170° C. and a pressure of 14 MPa, and then cold press for 8 minutes to obtain a cross-linked sheet; then crush into cross-linked plastic particles;

[0031] S3, single-core cable trial production: preheat the cross-linked plastic particles to 80°C and add them into the extruder to melt under high temperature and high pressure; then, at a temperature of 120°C and an extrusion pressure of 9-10MPa, uniformly extrude and coat them on the copper wire preheated to 80°C to form an insulating layer on the copper wire, and then degas at a temperature of 65°C for 7 days to obtain the trial-produced single-core cable;

[0032] S4. Performance test: Conduct mechanical property test and insulation performance test on the insulation layer of the trial-produced single-core cable. Once it meets the design requirements, formal production can be carried out according to the trial production method;

[0033] S5. Cable core twisting: Twist multiple single-core cables produced formally together to form a multi-core cable, and then use an extruder to extrude the sheath on the outside of the multi-core cable to form a complete wire and cable.

[0034] Example 2

[0035] In an embodiment of the present invention, a production process for electric wires and cables comprises the following steps:

[0036] S1. Add 85 parts of high-density polyethylene particles, 11 parts of methyl vinyl silicone rubber, 11 parts of ethylene propylene rubber particles and 0.25 parts of a compound of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol and tris(2,4-di-tert-butylphenyl)phosphite into an internal mixer by mass, and melt-blend for 6 minutes at a temperature of 140° C. and a speed of 70 r / min; then add 0.25 parts of triallyl phosphate and 0.25 parts of caprolactam, mix them evenly, and obtain a blend;

[0037] S2, vulcanization treatment: add 0.4 parts of a solution prepared by dicumyl peroxide powder and acetone at a ratio of 1:10 to the blend obtained in step S1, mix well, add to a flat vulcanizer, vulcanize for 11 minutes at a mold temperature of 175° C. and a pressure of 15 MPa, and then cold press for 9 minutes to obtain a cross-linked sheet; then crush into cross-linked plastic particles;

[0038] S3, single-core cable trial production: preheat the cross-linked plastic particles to 85°C and add them into the extruder to melt under high temperature and high pressure; then, at a temperature of 125°C and an extrusion pressure of 9.5MPa, uniformly extrude and coat them on the copper wire preheated to 80°C to form an insulating layer on the copper wire, and then degas the copper wire at a temperature of 50°C for 10 days to obtain the trial-produced single-core cable;

[0039] S4. Performance test: Conduct mechanical property test and insulation performance test on the insulation layer of the trial-produced single-core cable. Once it meets the design requirements, formal production can be carried out according to the trial production method.

[0040] S5. Cable core twisting: Twist multiple single-core cables produced formally together to form a multi-core cable, and then use an extruder to extrude the sheath on the outside of the multi-core cable to form a complete wire and cable.

[0041] Example 3

[0042] In an embodiment of the present invention, a production process for electric wires and cables comprises the following steps:

[0043] S1. Add 90 parts of high-density polyethylene particles, 12 parts of methyl vinyl silicone rubber, 12 parts of ethylene propylene rubber particles and 0.3 parts of a compound of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol and tris(2,4-di-tert-butylphenyl) phosphite into an internal mixer by mass, and melt-blend for 8 minutes at a temperature of 145° C. and a rotation speed of 80 r / min; then add 0.3 parts of triallyl phosphate and 0.3 parts of styrene, mix them evenly, and obtain a blend;

[0044] S2, vulcanization treatment: add 0.5 parts of a solution prepared by dicumyl peroxide powder and acetone at a ratio of 1:10 to the blend obtained in step S1, mix well, add to a flat vulcanizer, vulcanize for 12 minutes at a mold temperature of 180° C. and a pressure of 16 MPa, and then cold press for 10 minutes to obtain a cross-linked sheet; then crush into cross-linked plastic particles;

[0045] S3, single-core cable trial production: preheat the cross-linked plastic particles to 90°C and add them into the extruder to melt under high temperature and high pressure; then, at a temperature of 130°C and an extrusion pressure of 10MPa, uniformly extrude and coat them on the copper wire preheated to 85°C to form an insulating layer on the copper wire, and then degas the copper wire at a temperature of 75°C for 14 days to obtain the trial-produced single-core cable;

[0046] S4. Performance test: Conduct mechanical property test and insulation performance test on the insulation layer of the trial-produced single-core cable. Once it meets the design requirements, formal production can be carried out according to the trial production method.

[0047] S5. Cable core twisting: Twist multiple single-core cables produced formally together to form a multi-core cable, and then use an extruder to extrude the sheath on the outside of the multi-core cable to form a complete wire and cable.

[0048] In order to better illustrate the technical effect of the present invention, the following experiments are used to illustrate:

[0049] Example 1 of a high-voltage cross-linked polyethylene insulated power cable and its preparation process (CN114334293A) disclosed in the patent website is used as comparative example 1; the methyl vinyl mixed silicone rubber and EPDM rubber particles in Example 1 of the present invention are removed, and the rest remain unchanged as comparative example 2;

[0050] Samples of the insulating layer in Examples 1 to 3 of the present invention and Comparative Examples 1 and 2 were respectively taken for tensile test and aging test, wherein the size of the sample was 50 mm×10 mm×2 mm; in the tensile test, the sample was stretched at a speed of 100 mm / min, and the tensile strength (unit: MPa) and the elongation at break (unit: 100%) were measured; in the aging test, the tensile strength and the elongation at break were tested after aging for 168 h at a temperature of 178° C., and the retention rate of the tensile strength (K1) and the retention rate of the elongation at break (K2) were calculated, wherein,

[0051]

[0052] In the above formulas (3) and (4), p1 is the tensile strength after aging; q1 is the tensile strength before aging, l2 is the elongation at break after aging; h2 is the elongation at break before aging;

[0053] The tensile strength, elongation at break, tensile strength retention rate and elongation at break retention rate are recorded in Table 1 below.

[0054] Table 1 Analysis of tensile properties and aging properties

[0055]

[0056] It can be concluded from Table 1 above that before aging, the tensile strength and elongation at break of the cable insulation layer in Examples 1 to 3 of the present invention are significantly greater than those in Comparative Examples 1 and 2, and further, it can be concluded that the insulation layer in the present invention has excellent tensile strength and elongation at break, and has strong resistance and deformation ability when subjected to external force;

[0057] After aging, the retention rates of tensile strength and elongation at break of the cable insulation layer in Examples 1 to 3 of the present invention are significantly greater than those in Comparative Example 1 and Comparative Example 2. It can be concluded that the tensile strength and elongation at break of the insulation layer in the present invention are less affected in a high temperature environment, and still have strong resistance and deformation capabilities.

[0058] What is described above 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.

Claims

1. A process for producing electric wires and cables, characterized in that: The following steps are involved: S1. Material blending: 80-90 parts of high-density polyethylene particles, 10-12 parts of silicone rubber particles, 10-12 parts of EPDM rubber particles and 0.2-0.3 parts of antioxidant are added into an internal mixer by mass, and melt blended for 5-8 minutes at a temperature of 135-145° C. and a rotation speed of 60-80 r / min; then 0.2-0.3 parts of activator and 0.2-0.3 parts of anti-pre-crosslinking agent are added to mix uniformly to obtain a blend; S2, vulcanization treatment: adding 0.3-0.5 parts of dicumyl peroxide solution to the blend obtained in step S1, mixing evenly, adding to a flat vulcanizer for vulcanization treatment to obtain a cross-linked sheet; Then broken into cross-linked plastic particles; S3, single-core cable trial production: preheat the cross-linked plastic particles to 80-90°C and add them into the extruder to melt under high temperature and high pressure; then extrude and coat them evenly on the preheated conductor to form an insulating layer on the conductor, and then degas the conductor to obtain the trial-produced single-core cable; S4. Performance test: Conduct mechanical property test and insulation performance test on the insulation layer of the trial-produced single-core cable. Once it meets the design requirements, formal production can be carried out according to the trial production method. S5. Cable core twisting: Twist multiple single-core cables produced formally together to form a multi-core cable, and then use an extruder to extrude the sheath on the outside of the multi-core cable to form a complete wire and cable.

2. A wire and cable production process according to claim 1, characterized in that: In the step S1, The antioxidant is one or both of a compound of octadecyl beta-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite or a compound of pentaerythritol tetrakis[beta-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite; The silicone rubber particles are one or both of methyl vinyl compound silicone rubber and methyl vinyl silicone rubber; The activator is one or more of divinylbenzene, triallyl cyanurate, triallyl phosphate, and dimethacrylate; The anti-pre-crosslinking agent is one or both of styrene and caprolactam.

3. A wire and cable production process according to claim 1, characterized in that: In the step S2, the dicumyl peroxide solution is prepared by mixing dicumyl peroxide powder and acetone in a mass ratio of 1:

10.

4. A wire and cable production process according to claim 1, characterized in that: In the step S2, during the vulcanization process, the mold temperature of the flat vulcanizer is 170-180° C., the pressure is 14-16 MPa, the vulcanization time is 10-12 minutes, and then cold pressing is performed for 8-10 minutes.

5. A wire and cable production process according to claim 1, characterized in that: In the step S3, the extrusion temperature of the extruder is 120-130°C, the extrusion pressure is 9-10 MPa; and the preheating temperature of the conductor is 80-85°C.

6. A wire and cable production process according to claim 1, characterized in that: In the step S3, the degassing temperature is 65 to 75° C., and the degassing time is 7 to 14 days.

7. A process for producing electric wires and cables according to claim 1, characterized in that: In the step S4, the method for testing the mechanical properties of the insulation layer is as follows: taking an insulation layer sample from a single-core cable, performing a tensile test on the sample, calculating the stress and strain, and drawing a stress-strain curve of the sample; then obtaining the tensile yield stress, elongation at break, tensile strength and elastic modulus of the sample material from the curve to determine whether it meets the design requirements; wherein the calculation formula for the stress and strain is as follows: In the above formulas (1) and (2), σ is stress, A is the cross-sectional area of ​​the specimen, P is the tensile force, ε is strain, l is the length of the specimen when it breaks, and l0 is the original length of the specimen. The insulation performance test method of the insulation layer is as follows: heat the single-core cable from 20°C to 140°C at a heating rate of 10°C / min, keep it warm for one hour, and then test its insulation performance.

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