Anti-aging cable and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and provides an anti-aging cable and a preparation method thereof. The anti-aging cable comprises a conductor and a sheath layer, the sheath layer is prepared from the following raw materials in parts by weight: 40 to 60 parts of ethylene propylene diene monomer, 20 to 30 parts of ethylene-vinyl acetate copolymer, 20 to 22 parts of nano cellulose / montmorillonite composite material, 5 to 10 parts of nano silicon dioxide, 10 to 20 parts of magnesium hydroxide, 5 to 8 parts of zinc borate, 1.5 to 3 parts of composite antioxidant, 0.5 to 1.5 parts of ultraviolet light absorber, 1 to 1.2 parts of anti-aging agent and 1 to 2 parts of silane coupling agent. And 0.3 to 0.5 part of maleic anhydride grafted polypropylene. According to the anti-aging cable prepared in the invention, the high temperature resistance and the acid corrosion resistance of the anti-aging cable are improved, and the aging of the cable is effectively delayed.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to an aging-resistant cable and a preparation method thereof. Background Art

[0002] With the rapid development of the power industry, power cables, as important components for power transmission and distribution, have increasingly higher performance requirements. Especially in some special environments, such as high temperature, strong radiation, strong corrosion and other harsh conditions, the aging resistance of cables is particularly important. Traditional cable materials are often difficult to maintain their structure and performance for a long time in these environments, resulting in unstable power transmission and shortened cable service life. At present, there are some aging-resistant cable products on the market, which mainly improve their aging resistance by improving the insulation materials, sheath materials and fillers of the cables. For example, some cables use silane cross-linked polyethylene and thermoplastic polyethylene as heat-resistant layers to improve the high temperature resistance of the cables; some cables use special anti-corrosion materials and anti-radiation materials to enhance the corrosion resistance and radiation resistance of the cables.

[0003] However, these existing technologies still have some shortcomings. For example, the preparation process of some aging-resistant cables is complicated and costly, making them difficult to promote and apply on a large scale. In addition, some cables will still experience performance degradation and accelerated aging during long-term use, and cannot meet the needs of long-term stable operation.

[0004] In order to solve the above technical problems, the present invention proposes a new aging-resistant cable and a preparation method thereof. Summary of the invention

[0005] The present invention provides an aging-resistant cable and a preparation method thereof, which improve the high temperature resistance and acid corrosion resistance of the aging-resistant cable and effectively delay the aging of the cable.

[0006] The technical solution of the present invention is as follows: In the first aspect, the present invention provides an aging-resistant cable, comprising a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 40-60 parts of ethylene propylene rubber, 20-30 parts of ethylene-vinyl acetate copolymer, 20-22 parts of nanocellulose / montmorillonite composite material, 5-10 parts of nanosilicon dioxide, 10-20 parts of magnesium hydroxide, 5-8 parts of zinc borate, 1.5-3 parts of composite antioxidant, 0.5-1.5 parts of ultraviolet absorber, 1-1.2 parts of antioxidant, 1-2 parts of silane coupling agent, and 0.3-0.5 parts of maleic anhydride grafted polypropylene.

[0007] As a further technical solution, the preparation method of the nanocellulose / montmorillonite composite material includes: mixing an oxidative pretreated wood pulp fiber suspension and an organically modified montmorillonite in a weight ratio of 100:4-6 to obtain a mixed material, adding 0.5wt% of polyethylene glycol relative to the mixed material, first ultrasonically treating the mixed material at 20-25kHz for 30-40min, and then shearing and dispersing the mixed material at 50-60°C through a twin-screw extruder.

[0008] As a further technical solution, the oxidation pretreatment method comprises: mixing wood pulp fiber, TEMPO oxidant, NaClO 2 and buffer solution, with magnetic stirring at 500-600 rpm for 48 h, and then subjected to high-pressure homogenization at a pressure of 150-160 MPa for 4-6 cycles to obtain a nanocellulose fiber suspension with an average diameter of 3-5 nm and an average length of 1-2 μm.

[0009] As a further technical solution, the buffer is NaHCO 3 / Na 2 CO 3 The concentration is 0.1 M, and the pH is 10; the wood pulp fiber, TEMPO oxidant, NaClO 2 The dosage ratio of the buffer solution is 50-60g:0.1-0.3g:4-5g:1L.

[0010] As a further technical solution, the preparation method of the organically modified montmorillonite comprises: mixing sodium montmorillonite, hexadecyltrimethylammonium bromide and deionized water in a weight ratio of 1g:3-4g:400-500mL, performing ion exchange reaction in a water bath at 70-80°C and a rotation speed of 260-340rpm for 24-30h, and centrifuging and washing until there is no Br - It can be obtained after drying at 55-65℃ for 10-14h.

[0011] As a further technical solution, the composite oxidant includes antioxidant 1010 and antioxidant 168 in a weight ratio of 2-3:1.

[0012] As a further technical solution, the ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

[0013] In a second aspect, the present invention provides a method for preparing an aging-resistant cable, the steps comprising: S1, internal mixing and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into an internal mixer for mixing; adding nano-silicon dioxide, nano-cellulose / montmorillonite composite material, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene and then internal mixing to obtain a rubber material; S2. Extrusion vulcanization: the rubber material is extruded through a twin-screw extruder and coated on the surface of the conductor; then electron irradiation cross-linking is adopted with an irradiation dose of 15-20 kGy, and finally an aging-resistant cable is obtained.

[0014] As a further technical solution, the mixing temperature is 115-125°C, and the mixing time is 5-7 minutes; the mixing step includes: first heating to 140-150°C and mixing for 10-14 minutes; then cooling to 100-110°C and continuing mixing for 8-10 minutes.

[0015] As a further technical solution, the temperature of the first zone of the twin-screw extruder is 150-160°C, the temperature of the second zone is 160-170°C, and the temperature of the die head is 170-180°C.

[0016] The working principle and beneficial effects of the present invention are: The EPDM rubber in the present invention has good heat resistance, aging resistance and electrical insulation, and can maintain stable performance at higher temperatures; the ethylene-vinyl acetate copolymer improves the flexibility and impact resistance of the cable sheath material, and also helps to improve the high temperature resistance.

[0017] In the present invention, nanocellulose and organically modified montmorillonite are compounded to form a more compact structure, thereby improving the overall high temperature resistance of the material. The composite material can also form a dense protective layer to reduce the erosion of the cable material by the external environment (such as light, heat, oxygen, etc.), thereby delaying the aging of the cable.

[0018] Among them, nanocellulose has high crystallinity and high strength, can keep the structure of the material stable at high temperature, and is not easy to deform or melt. In addition, the nanoscale effect of nanocellulose enables it to form a large number of interface contact points in the composite material, which can effectively transfer and disperse heat, thereby improving the thermal stability of the material and reducing cracks and deformation caused by aging. The compatibility of organically modified montmorillonite with the polymer matrix is ​​significantly improved, and a good dispersed structure can be formed in the composite material. At the same time, montmorillonite itself has good thermal stability, can keep the structure stable at high temperature, and further improve the high temperature resistance of the composite material. The composite of nanocellulose and organically modified montmorillonite can form a more compact and stable structure, which can effectively prevent the transfer of heat at high temperature, thereby delaying the thermal aging process of the material.

[0019] In terms of corrosion resistance, the high specific surface area and nanoscale effect of nanocellulose enable it to form a dense protective layer in the composite material, which can effectively prevent acidic substances from corroding the cable material. The organically modified montmorillonite has excellent barrier properties, which can effectively prevent the penetration of acidic substances and water molecules, further improving the acid corrosion resistance of cable materials. The composite of nanocellulose and organically modified montmorillonite can form a more complete protective barrier, which can effectively prevent the corrosion of acidic substances and water molecules, thereby extending the service life of the cable.

[0020] The combination of antioxidant 1010 and antioxidant 168 can effectively capture free radicals at high temperatures and prevent the oxidative degradation of polymers, thereby improving the high temperature resistance of cable materials. When used with antioxidant 4020, it can exert a synergistic effect, further inhibit the aging process of cable materials, and extend the service life of cables. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that the EPDM model in the present invention is EPDM 4045; the ethylene-vinyl acetate copolymer model is EVA 2803; the maleic anhydride grafted polypropylene model is Polybond 3150; the wood pulp fiber is purchased from Dalian Yangrun Trading Co., Ltd., item number: Y0006; and the montmorillonite model is DK-4.

[0023] Example 1 The present embodiment provides an aging-resistant cable, comprising a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 50 parts of ethylene propylene rubber, 25 parts of ethylene-vinyl acetate copolymer, 21 parts of nanocellulose / montmorillonite composite material, 7 parts of nanosilicon dioxide, 15 parts of magnesium hydroxide, 6 parts of zinc borate, 2 parts of composite antioxidant, 1 part of ultraviolet absorber, 1.1 parts of antioxidant, 1.5 parts of silane coupling agent, and 0.4 parts of maleic anhydride grafted polypropylene.

[0024] The preparation method of the nanocellulose / montmorillonite composite material comprises: Wood pulp fiber, TEMPO oxidant, NaClO 2The suspension was prepared by magnetic stirring at 550 rpm for 48 h in a buffer solution and then pulverized by a high-pressure homogenizer at a pressure of 155 MPa for 5 cycles to obtain a nanocellulose fiber suspension with an average diameter of 4 nm and an average length of 1.5 μm. The buffer solution was NaHCO 3 / Na 2 CO 3 The concentration is 0.1M, pH is 10; wood pulp fiber, TEMPO oxidant, NaClO 2 The dosage ratio of the buffer solution is 55 g: 0.2 g: 4.5 g: 1 L; The preparation method of organic modified montmorillonite comprises: mixing sodium montmorillonite, hexadecyltrimethylammonium bromide and deionized water in a weight ratio of 1 g:3.5 g:450 mL, performing ion exchange reaction in a water bath at 75°C and a rotation speed of 300 rpm for 27 hours, and centrifuging and washing until there is no Br - Detection, dried at 60℃ for 12h; A mixture was obtained by mixing an oxidatively pretreated wood pulp fiber suspension and an organically modified montmorillonite in a weight ratio of 100:5, and 0.5 wt % of polyethylene glycol was added to the mixture. The mixture was first ultrasonically treated at 22 kHz for 35 minutes, and then sheared and dispersed by a twin-screw extruder at 55° C., wherein the screw speed was 250 rpm and the residence time was 7 minutes.

[0025] The composite oxidant includes antioxidant 1010 and antioxidant 168 in a weight ratio of 2.5:1; the ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

[0026] The preparation method of the aging-resistant cable comprises the following steps: S1, banburying and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into a banburying machine and mixing them at a temperature of 120° C. for 6 minutes; adding nano-silicon dioxide, nano-cellulose / montmorillonite composite material, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene and then banburying, the banburying steps comprising: first heating to 145° C. and mixing for 12 minutes; then cooling to 105° C. and continuing to mix for 9 minutes to obtain a uniform rubber material; S2. Extrusion vulcanization: The rubber compound is extruded and coated on the surface of the conductor through a twin-screw extruder. The temperature of the first zone of the twin-screw extruder is 155°C, the temperature of the second zone is 165°C, and the temperature of the die head is 175°C. Subsequently, electron irradiation cross-linking is adopted with an irradiation dose of 17kGy to finally obtain an aging-resistant cable.

[0027] Example 2 The present embodiment provides an aging-resistant cable, comprising a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 40 parts of ethylene propylene rubber, 20 parts of ethylene-vinyl acetate copolymer, 20 parts of nano-cellulose / montmorillonite composite material, 5 parts of nano-silicon dioxide, 10 parts of magnesium hydroxide, 5 parts of zinc borate, 1.5 parts of composite antioxidant, 0.5 parts of ultraviolet absorber, 1 part of antioxidant, 1 part of silane coupling agent, and 0.3 parts of maleic anhydride grafted polypropylene.

[0028] The preparation method of the nanocellulose / montmorillonite composite material comprises: Wood pulp fiber, TEMPO oxidant, NaClO 2 The suspension was prepared by magnetic stirring at 500 rpm for 48 h in a buffer solution and then pulverized by a high-pressure homogenizer at a pressure of 150 MPa for 4 cycles to obtain a nanocellulose fiber suspension with an average diameter of 3 nm and an average length of 1 μm. The buffer solution was NaHCO 3 / Na 2 CO 3 The concentration is 0.1M, pH is 10; wood pulp fiber, TEMPO oxidant, NaClO 2 The dosage ratio of the buffer solution is 50 g: 0.1 g: 4 g: 1 L; The preparation method of organic modified montmorillonite comprises: mixing sodium montmorillonite, hexadecyltrimethylammonium bromide and deionized water in a weight ratio of 1 g:3 g:400 mL, performing ion exchange reaction in a water bath at 70°C and a rotation speed of 260 rpm for 24 hours, and centrifuging and washing until there is no Br - Detection, dried at 55℃ for 10h; A mixture was obtained by mixing an oxidatively pretreated wood pulp fiber suspension and an organically modified montmorillonite in a weight ratio of 100:4, adding 0.5 wt % of polyethylene glycol relative to the mixture, firstly ultrasonically treating at 20 kHz for 30 min, and then shearing and dispersing by a twin-screw extruder at 50° C., wherein the screw speed was 200 rpm and the residence time was 5 minutes.

[0029] The composite oxidant includes antioxidant 1010 and antioxidant 168 in a weight ratio of 2:1; the ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

[0030] The preparation method of the aging-resistant cable comprises the following steps: S1, banburying and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into a banburying machine and mixing them at a temperature of 115° C. for 5 minutes; adding nano-silicon dioxide, nano-cellulose / montmorillonite composite material, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene and then banburying, the banburying steps comprising: first heating to 140° C. and mixing for 10-14 minutes; then cooling to 100° C. and continuing mixing for 8 minutes to obtain a uniform rubber material; S2. Extrusion vulcanization: The rubber compound is extruded and coated on the surface of the conductor through a twin-screw extruder. The temperature of the first zone of the twin-screw extruder is 150°C, the temperature of the second zone is 160°C, and the temperature of the die head is 170°C. Subsequently, electron irradiation cross-linking is adopted with an irradiation dose of 15kGy to finally obtain an aging-resistant cable.

[0031] Example 3 The present embodiment provides an aging-resistant cable, comprising a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 60 parts of ethylene propylene rubber, 30 parts of ethylene-vinyl acetate copolymer, 22 parts of nano-cellulose / montmorillonite composite material, 10 parts of nano-silicon dioxide, 20 parts of magnesium hydroxide, 8 parts of zinc borate, 3 parts of composite antioxidant, 1.5 parts of ultraviolet absorber, 1.2 parts of antioxidant, 2 parts of silane coupling agent, and 0.5 parts of maleic anhydride grafted polypropylene.

[0032] The preparation method of the nanocellulose / montmorillonite composite material comprises: Wood pulp fiber, TEMPO oxidant, NaClO 2 The suspension was prepared by magnetic stirring at 600 rpm for 48 h in a buffer solution and then pulverized by a high-pressure homogenizer at a pressure of 160 MPa for 6 cycles to obtain a nanocellulose fiber suspension with an average diameter of 5 nm and an average length of 2 μm. The buffer solution was NaHCO 3 / Na 2 CO 3 The concentration was 0.1 M, pH 10; wood pulp fiber, TEMPO oxidant, NaClO 2 The dosage ratio of the buffer solution is 60 g: 0.3 g: 5 g: 1 L; The preparation method of organic modified montmorillonite comprises: mixing sodium montmorillonite, hexadecyltrimethylammonium bromide and deionized water in a weight ratio of 1 g:4 g:500 mL, performing ion exchange reaction for 30 h in a water bath at 80°C and a rotation speed of 340 rpm, and centrifuging and washing until there is no Br - Detection, dried at 65℃ for 14h; A mixture was obtained by mixing an oxidatively pretreated wood pulp fiber suspension and an organically modified montmorillonite in a weight ratio of 100:6, and 0.5 wt % of polyethylene glycol relative to the mixture was added. The mixture was first ultrasonically treated at 25 kHz for 40 minutes, and then sheared and dispersed by a twin-screw extruder at 60° C., wherein the screw speed was 300 rpm and the residence time was 10 minutes.

[0033] The composite oxidant includes antioxidant 1010 and antioxidant 168 in a weight ratio of 3:1; the ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

[0034] The preparation method of the aging-resistant cable comprises the following steps: S1, banburying and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into a banburying machine and mixing them at a temperature of 125° C. for 7 minutes; adding nano-silicon dioxide, nano-cellulose / montmorillonite composite material, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene and then banburying, the banburying steps comprising: first heating to 150° C. and mixing for 14 minutes; then cooling to 110° C. and continuing mixing for 10 minutes to obtain a uniform rubber material; S2. Extrusion vulcanization: The rubber compound is extruded and coated on the surface of the conductor through a twin-screw extruder. The temperature of the first zone of the twin-screw extruder is 160°C, the temperature of the second zone is 170°C, and the temperature of the die head is 180°C. Subsequently, electron irradiation cross-linking is adopted with an irradiation dose of 20kGy to finally obtain an aging-resistant cable.

[0035] Comparative Example 1 The comparative example provides an aging-resistant cable, comprising a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 50 parts of EPDM rubber, 25 parts of ethylene-vinyl acetate copolymer, 21 parts of nanocellulose / montmorillonite composite material, 7 parts of nanosilicon dioxide, 15 parts of magnesium hydroxide, 6 parts of zinc borate, 2 parts of composite antioxidant, 1 part of ultraviolet absorber, 1.1 parts of antioxidant, 1.5 parts of silane coupling agent, and 0.4 parts of maleic anhydride grafted polypropylene.

[0036] The preparation method of the nanocellulose / montmorillonite composite material comprises: Wood pulp fiber, TEMPO oxidant, NaClO 2 The suspension was prepared by magnetic stirring at 550 rpm for 48 h in a buffer solution and then crushed by a high-pressure homogenizer at a pressure of 155 MPa for 5 cycles to obtain a nanocellulose fiber suspension with an average diameter of 4 nm and an average length of 1.5 μm. The buffer solution was NaHCO 3 / Na 2 CO 3The concentration was 0.1 M, pH 10; wood pulp fiber, TEMPO oxidant, NaClO 2 The dosage ratio of the buffer solution is 55 g: 0.2 g: 4.5 g: 1 L; A wood pulp fiber suspension after oxidation pretreatment and montmorillonite in a weight ratio of 100:5 were mixed to obtain a mixture, and 0.5 wt % of polyethylene glycol relative to the mixture was added, firstly ultrasonically treated at 22 kHz for 35 minutes, and then shear dispersed by a twin-screw extruder at 55° C., wherein the screw speed was 250 rpm and the residence time was 7 minutes.

[0037] The composite oxidant includes antioxidant 1010 and antioxidant 168 in a weight ratio of 2.5:1; the ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

[0038] The preparation method of the aging-resistant cable comprises the following steps: S1, banburying and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into a banburying machine and mixing them at a temperature of 120° C. for 6 minutes; adding nano-silicon dioxide, nano-cellulose / montmorillonite composite material, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene and then banburying, the banburying steps comprising: first heating to 145° C. and mixing for 12 minutes; then cooling to 105° C. and continuing to mix for 9 minutes to obtain a uniform rubber material; S2. Extrusion vulcanization: The rubber compound is extruded and coated on the surface of the conductor through a twin-screw extruder. The temperature of the first zone of the twin-screw extruder is 155°C, the temperature of the second zone is 165°C, and the temperature of the die head is 175°C. Subsequently, electron irradiation cross-linking is adopted with an irradiation dose of 17kGy to finally obtain an aging-resistant cable.

[0039] Comparative Example 2 The comparative example provides an aging-resistant cable, comprising a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 50 parts of ethylene propylene rubber, 25 parts of ethylene-vinyl acetate copolymer, 21 parts of organically modified montmorillonite, 7 parts of nano-silicon dioxide, 15 parts of magnesium hydroxide, 6 parts of zinc borate, 2 parts of composite antioxidant, 1 part of ultraviolet absorber, 1.1 parts of antioxidant, 1.5 parts of silane coupling agent, and 0.4 parts of maleic anhydride grafted polypropylene.

[0040] The preparation method of the organically modified montmorillonite comprises: mixing sodium montmorillonite, hexadecyltrimethylammonium bromide and deionized water in a weight ratio of 1 g:3.5 g:450 mL, performing an ion exchange reaction in a water bath at 75°C and a rotation speed of 300 rpm for 27 hours, and centrifuging and washing until there is no Br -Detection, dried at 60℃ for 12h; The composite oxidant includes antioxidant 1010 and antioxidant 168 in a weight ratio of 2.5:1; the ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

[0041] The preparation method of the aging-resistant cable comprises the following steps: S1, banburying and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into a banburying machine and mixing them at a temperature of 120° C. for 6 minutes; adding nano-silicon dioxide, organically modified montmorillonite, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene and then banburying, the banburying steps comprising: first heating to 145° C. and mixing for 12 minutes; then cooling to 105° C. and continuing mixing for 9 minutes to obtain a uniform rubber material; S2. Extrusion vulcanization: The rubber compound is extruded and coated on the surface of the conductor through a twin-screw extruder. The temperature of the first zone of the twin-screw extruder is 155°C, the temperature of the second zone is 165°C, and the temperature of the die head is 175°C. Subsequently, electron irradiation cross-linking is adopted with an irradiation dose of 17kGy to finally obtain an aging-resistant cable.

[0042] Comparative Example 3 The comparative example provides an aging-resistant cable, comprising a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 50 parts of EPDM rubber, 25 parts of ethylene-vinyl acetate copolymer, 21 parts of montmorillonite, 7 parts of nano-silicon dioxide, 15 parts of magnesium hydroxide, 6 parts of zinc borate, 2 parts of composite antioxidant, 1 part of ultraviolet absorber, 1.1 parts of antioxidant, 1.5 parts of silane coupling agent, and 0.4 parts of maleic anhydride grafted polypropylene.

[0043] The composite oxidant includes antioxidant 1010 and antioxidant 168 in a weight ratio of 2.5:1; the ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

[0044] The preparation method of the aging-resistant cable comprises the following steps: S1, banburying and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into a banburying machine and mixing them at a temperature of 120° C. for 6 minutes; adding nano-silicon dioxide, montmorillonite, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene and then banburying, the banburying steps comprising: first heating to 145° C. and mixing for 12 minutes; then cooling to 105° C. and continuing to mix for 9 minutes to obtain a uniform rubber material; S2. Extrusion vulcanization: The rubber compound is extruded and coated on the surface of the conductor through a twin-screw extruder. The temperature of the first zone of the twin-screw extruder is 155°C, the temperature of the second zone is 165°C, and the temperature of the die head is 175°C. Subsequently, electron irradiation cross-linking is adopted with an irradiation dose of 17kGy to finally obtain an aging-resistant cable.

[0045] Comparative Example 4 The comparative example provides an aging-resistant cable, comprising a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 50 parts of EPDM rubber, 25 parts of ethylene-vinyl acetate copolymer, 7 parts of nano-silicon dioxide, 15 parts of magnesium hydroxide, 6 parts of zinc borate, 2 parts of composite antioxidant, 1 part of ultraviolet absorber, 1.1 parts of antioxidant, 1.5 parts of silane coupling agent, and 0.4 parts of maleic anhydride grafted polypropylene.

[0046] The composite oxidant includes antioxidant 1010 and antioxidant 168 in a weight ratio of 2.5:1; the ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

[0047] The preparation method of the aging-resistant cable comprises the following steps: S1, banburying and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into a banburying machine and mixing them at a temperature of 120° C. for 6 minutes; adding nano silicon dioxide, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene and then banburying, the banburying steps comprising: first heating to 145° C. and mixing for 12 minutes; then cooling to 105° C. and continuing to mix for 9 minutes to obtain a uniform rubber material; S2. Extrusion vulcanization: The rubber compound is extruded and coated on the surface of the conductor through a twin-screw extruder. The temperature of the first zone of the twin-screw extruder is 155°C, the temperature of the second zone is 165°C, and the temperature of the die head is 175°C. Subsequently, electron irradiation cross-linking is adopted with an irradiation dose of 17kGy to finally obtain an aging-resistant cable.

[0048] Comparative Example 5 The present embodiment provides an aging-resistant cable, including a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 50 parts of ethylene propylene rubber, 25 parts of ethylene-vinyl acetate copolymer, 21 parts of nanocellulose / montmorillonite composite material, 7 parts of nanosilicon dioxide, 15 parts of magnesium hydroxide, 2 parts of composite antioxidant, 1 part of ultraviolet absorber, 1.1 parts of antioxidant, 1.5 parts of silane coupling agent, and 0.4 parts of maleic anhydride grafted polypropylene.

[0049] The preparation method of the nanocellulose / montmorillonite composite material comprises: Wood pulp fiber, TEMPO oxidant, NaClO 2The suspension was prepared by magnetic stirring at 550 rpm for 48 h in a buffer solution and then crushed by a high-pressure homogenizer at a pressure of 155 MPa for 5 cycles to obtain a nanocellulose fiber suspension with an average diameter of 4 nm and an average length of 1.5 μm. The buffer solution was NaHCO 3 / Na 2 CO 3 The concentration was 0.1 M, pH 10; wood pulp fiber, TEMPO oxidant, NaClO 2 The dosage ratio of the buffer solution is 55 g: 0.2 g: 4.5 g: 1 L; The preparation method of organic modified montmorillonite comprises: mixing sodium montmorillonite, hexadecyltrimethylammonium bromide and deionized water in a weight ratio of 1 g:3.5 g:450 mL, performing ion exchange reaction in a water bath at 75°C and a rotation speed of 300 rpm for 27 hours, and centrifuging and washing until there is no Br - Detection, dried at 60℃ for 12h; A mixture was obtained by mixing an oxidatively pretreated wood pulp fiber suspension and an organically modified montmorillonite in a weight ratio of 100:5, and 0.5 wt % of polyethylene glycol was added to the mixture. The mixture was first ultrasonically treated at 22 kHz for 35 minutes, and then sheared and dispersed by a twin-screw extruder at 55° C., wherein the screw speed was 250 rpm and the residence time was 7 minutes.

[0050] The composite oxidant includes antioxidant 1010 and antioxidant 168 in a weight ratio of 2.5:1; the ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

[0051] The preparation method of the aging-resistant cable comprises the following steps: S1, banburying and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into a banburying machine and mixing them at a temperature of 120° C. for 6 minutes; adding nano-silicon dioxide, nano-cellulose / montmorillonite composite material, magnesium hydroxide, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene and then banburying, the banburying steps comprising: first heating to 145° C. and mixing for 12 minutes; then cooling to 105° C. and continuing to mix for 9 minutes to obtain a uniform rubber material; S2. Extrusion vulcanization: The rubber compound is extruded and coated on the surface of the conductor through a twin-screw extruder. The temperature of the first zone of the twin-screw extruder is 155°C, the temperature of the second zone is 165°C, and the temperature of the die head is 175°C. Subsequently, electron irradiation cross-linking is adopted with an irradiation dose of 17kGy to finally obtain an aging-resistant cable.

[0052] Comparative Example 6 The comparative example provides an aging-resistant cable, comprising a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 50 parts of EPDM rubber, 25 parts of ethylene-vinyl acetate copolymer, 21 parts of nanocellulose / montmorillonite composite material, 7 parts of nanosilicon dioxide, 15 parts of magnesium hydroxide, 6 parts of zinc borate, 2 parts of antioxidant, 1 part of ultraviolet absorber, 1.1 parts of antioxidant, 1.5 parts of silane coupling agent, and 0.4 parts of maleic anhydride grafted polypropylene.

[0053] The preparation method of the nanocellulose / montmorillonite composite material comprises: Wood pulp fiber, TEMPO oxidant, NaClO 2 The suspension was prepared by magnetic stirring at 550 rpm for 48 h in a buffer solution and then crushed by a high-pressure homogenizer at a pressure of 155 MPa for 5 cycles to obtain a nanocellulose fiber suspension with an average diameter of 4 nm and an average length of 1.5 μm. The buffer solution was NaHCO 3 / Na 2 CO 3 The concentration was 0.1 M, pH 10; wood pulp fiber, TEMPO oxidant, NaClO 2 The dosage ratio of the buffer solution is 55 g: 0.2 g: 4.5 g: 1 L; The preparation method of organic modified montmorillonite comprises: mixing sodium montmorillonite, hexadecyltrimethylammonium bromide and deionized water in a weight ratio of 1 g:3.5 g:450 mL, performing ion exchange reaction in a water bath at 75°C and a rotation speed of 300 rpm for 27 hours, and centrifuging and washing until there is no Br - Detection, dried at 60℃ for 12h; A mixture was obtained by mixing an oxidatively pretreated wood pulp fiber suspension and an organically modified montmorillonite in a weight ratio of 100:5, and 0.5 wt % of polyethylene glycol was added to the mixture. The mixture was first ultrasonically treated at 22 kHz for 35 minutes, and then sheared and dispersed by a twin-screw extruder at 55° C., wherein the screw speed was 250 rpm and the residence time was 7 minutes.

[0054] Among them, the oxidant is antioxidant 1010; the ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

[0055] The preparation method of the aging-resistant cable comprises the following steps: S1, banburying and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into a banburying machine and mixing them at a temperature of 120° C. for 6 minutes; adding nano-silicon dioxide, nano-cellulose / montmorillonite composite material, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene and then banburying, the banburying steps comprising: first heating to 145° C. and mixing for 12 minutes; then cooling to 105° C. and continuing to mix for 9 minutes to obtain a uniform rubber material; S2. Extrusion vulcanization: The rubber compound is extruded and coated on the surface of the conductor through a twin-screw extruder. The temperature of the first zone of the twin-screw extruder is 155°C, the temperature of the second zone is 165°C, and the temperature of the die head is 175°C. Subsequently, electron irradiation cross-linking is adopted with an irradiation dose of 17kGy to finally obtain an aging-resistant cable.

[0056] Comparative Example 7 The comparative example provides an aging-resistant cable, comprising a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 50 parts of EPDM rubber, 25 parts of ethylene-vinyl acetate copolymer, 21 parts of nanocellulose / montmorillonite composite material, 7 parts of nanosilicon dioxide, 15 parts of magnesium hydroxide, 6 parts of zinc borate, 2 parts of composite antioxidant, 1 part of ultraviolet absorber, 1.5 parts of silane coupling agent, and 0.4 parts of maleic anhydride grafted polypropylene.

[0057] The preparation method of the nanocellulose / montmorillonite composite material comprises: Wood pulp fiber, TEMPO oxidant, NaClO 2 The suspension was prepared by magnetic stirring at 550 rpm for 48 h in a buffer solution and then crushed by a high-pressure homogenizer at a pressure of 155 MPa for 5 cycles to obtain a nanocellulose fiber suspension with an average diameter of 4 nm and an average length of 1.5 μm. The buffer solution was NaHCO 3 / Na 2 CO 3 The concentration was 0.1 M, pH 10; wood pulp fiber, TEMPO oxidant, NaClO 2 The dosage ratio of the buffer solution is 55 g: 0.2 g: 4.5 g: 1 L; The preparation method of organic modified montmorillonite comprises: mixing sodium montmorillonite, hexadecyltrimethylammonium bromide and deionized water in a weight ratio of 1 g:3.5 g:450 mL, performing ion exchange reaction in a water bath at 75°C and a rotation speed of 300 rpm for 27 hours, and centrifuging and washing until there is no Br - Detection, dried at 60℃ for 12h; A mixture was obtained by mixing an oxidatively pretreated wood pulp fiber suspension and an organically modified montmorillonite in a weight ratio of 100:5, and 0.5 wt % of polyethylene glycol was added to the mixture. The mixture was first ultrasonically treated at 22 kHz for 35 minutes, and then sheared and dispersed by a twin-screw extruder at 55° C., wherein the screw speed was 250 rpm and the residence time was 7 minutes.

[0058] The composite oxidant includes antioxidant 1010 and antioxidant 168 in a weight ratio of 2.5:1; the ultraviolet absorber is ultraviolet absorber UV-531; and the silane coupling agent is silane coupling agent KH550.

[0059] The preparation method of the aging-resistant cable comprises the following steps: S1, banburying and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into a banburying machine and mixing them at a temperature of 120° C. for 6 minutes; adding nano-silicon dioxide, nano-cellulose / montmorillonite composite material, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, silane coupling agent and maleic anhydride grafted polypropylene and then banburying, the banburying steps comprising: first heating to 145° C. and mixing for 12 minutes; then cooling to 105° C. and continuing to mix for 9 minutes to obtain a uniform rubber material; S2. Extrusion vulcanization: The rubber compound is extruded and coated on the surface of the conductor through a twin-screw extruder. The temperature of the first zone of the twin-screw extruder is 155°C, the temperature of the second zone is 165°C, and the temperature of the die head is 175°C. Subsequently, electron irradiation cross-linking is adopted with an irradiation dose of 17kGy to finally obtain an aging-resistant cable.

[0060] Test Example: The outer sheaths of the aging-resistant cables prepared in the above-mentioned Examples 1-3 and Comparative Examples 1-7 were tested as follows: 1. Tensile strength and elongation at break: Tested in accordance with GB / T2951.11-2008; 2. Aging resistance: Refer to GB / T2951.11-2008, place the sample at 100℃ for 72h for heat aging test, test the tensile strength again after the test, and calculate the tensile strength retention rate according to the following calculation formula; Tensile strength retention rate (%) = tensile strength after heat aging / tensile strength before heat aging × 100%; 3. Acid resistance: The test temperature is 25°C. Soak the sample in a 10% hydrochloric acid solution for one month and observe whether the surface is bubbling or damaged.

[0061] The test results are shown in Table 1 below: Table 1

[0062] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An aging-resistant cable, characterized in that: The invention comprises a conductor and a sheath layer, wherein the sheath layer is composed of the following raw materials in parts by weight: 40-60 parts of EPDM rubber, 20-30 parts of ethylene-vinyl acetate copolymer, 20-22 parts of nano cellulose / montmorillonite composite material, 5-10 parts of nano silicon dioxide, 10-20 parts of magnesium hydroxide, 5-8 parts of zinc borate, 1.5-3 parts of composite antioxidant, 0.5-1.5 parts of ultraviolet absorber, 1-1.2 parts of antioxidant, 1-2 parts of silane coupling agent and 0.3-0.5 parts of maleic anhydride grafted polypropylene.

2. The aging-resistant cable according to claim 1, characterized in that: The preparation method of the nanocellulose / montmorillonite composite material comprises: mixing a wood pulp fiber suspension after oxidation pretreatment and an organically modified montmorillonite in a weight ratio of 100:4-6 to obtain a mixed material, adding 0.5wt% of polyethylene glycol relative to the mixed material, firstly ultrasonically treating the mixed material at 20-25kHz for 30-40min, and then shearing and dispersing the mixed material at 50-60°C through a twin-screw extruder.

3. The aging-resistant cable according to claim 2, characterized in that: The oxidation pretreatment method comprises: placing wood pulp fibers, TEMPO oxidant, NaClO2 and buffer, magnetically stirring at 500-600 rpm for 48 hours, passing through a high-pressure homogenizer at a pressure of 150-160 MPa, circulating 4-6 times, and crushing to obtain a nanocellulose fiber suspension with an average diameter of 3-5 nm and an average length of 1-2 μm.

4. The aging-resistant cable according to claim 3, characterized in that: The buffer solution is NaHCO3 / Na2CO3, with a concentration of 0.1M and a pH of 10; the usage ratio of the wood pulp fiber, TEMPO oxidant, NaClO2 and buffer solution is 50-60g: 0.1-0.3g: 4-5g: 1L.

5. The aging-resistant cable according to claim 2, characterized in that: The preparation method of the organically modified montmorillonite comprises: mixing sodium montmorillonite, hexadecyltrimethylammonium bromide and deionized water in a weight ratio of 1 g: 3-4 g: 400-500 mL, performing ion exchange reaction in a water bath at 70-80° C. and a rotation speed of 260-340 rpm for 24-30 hours, and centrifuging and washing until there is no Br - It can be obtained after drying at 55-65℃ for 10-14h.

6. The aging-resistant cable according to claim 1, characterized in that: The composite oxidant comprises antioxidant 1010 and antioxidant 168 in a weight ratio of 2-3:

1.

7. The aging-resistant cable according to claim 1, characterized in that: The ultraviolet absorber is ultraviolet absorber UV-531; the antioxidant is antioxidant 4020; and the silane coupling agent is silane coupling agent KH550.

8. The method for preparing an aging-resistant cable according to any one of claims 1 to 7, characterized in that the steps include: S1. Internal mixing and blending: adding EPDM rubber and ethylene-vinyl acetate copolymer into an internal mixer for mixing; Adding nano silicon dioxide, nano cellulose / montmorillonite composite material, magnesium hydroxide, zinc borate, composite antioxidant, ultraviolet absorber, antioxidant, silane coupling agent and maleic anhydride grafted polypropylene, and then performing banburying to obtain a rubber material; S2. Extrusion vulcanization: the rubber material is extruded through a twin-screw extruder and coated on the surface of the conductor; then electron irradiation cross-linking is adopted with an irradiation dose of 15-20 kGy, and finally an aging-resistant cable is obtained.

9. The method for preparing an aging-resistant cable according to claim 8, characterized in that: The mixing temperature is 115-125° C., and the mixing time is 5-7 minutes. The mixing step includes: first heating to 140-150° C. and mixing for 10-14 minutes; then cooling to 100-110° C. and continuing mixing for 8-10 minutes.

10. The method for preparing an aging-resistant cable according to claim 9, characterized in that: The temperature of the first zone of the twin-screw extruder is 150-160°C, the temperature of the second zone is 160-170°C, and the temperature of the die head is 170-180°C.

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