Composition as well as preparation method and application thereof

Abstract

The invention relates to the technical field of composite materials, and discloses a composition and a preparation method and application thereof, the composition comprises resin, conductive carbon black, a first antioxidant, a second antioxidant and a cross-linking agent; wherein the mass content of metal elements in the conductive carbon black is not more than 10 ppm; wherein the first antioxidant is 2, 4, 6-tri (3 ', 5'-di-tert-butyl-4 '-hydroxybenzyl) mesitylene and / or 1, 3, 5-tri (3, 5-di-tert-butyl-4'-hydroxybenzyl) isocyanuric acid, and the second antioxidant is 2, 4, 6-tri (3 ', 5'-di-tert-butyl-4 '-hydroxybenzyl) mesitylene. Wherein the second antioxidant is bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and / or pentaerythritol tetra (3-lauryl thiopropionate), and the second antioxidant is a mixture of the first antioxidant and the second antioxidant. As a semiconductive shielding material, the composition provided by the invention not only has excellent insulation yellowing resistance, but also has excellent mechanical property and conductivity, and ensures better application of the material in preparation of power cables.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly to a composition, a preparation method and an application thereof. Background Art

[0002] Power cables are generally composed of a metal conductor, an inner semiconductive shielding layer, an insulating layer, an outer semiconductive shielding layer, and an outer protective material, etc. Among them, the semiconductive shielding layer plays a role in uniforming the electric field and protecting the main insulating material, and its performance greatly affects the operation stability of the entire cable system. Currently, the semiconductive shielding materials are generally prepared by blending chemically crosslinked polyolefin materials and conductive carbon black, and the preparation process is relatively mature. However, there is generally a serious problem that the insulating layer is yellowed at the interface between the semiconductive shielding material and the insulating material, and usually its yellow index is greater than 5. This is mainly caused by the influence of the semiconductive shielding material on the insulating interface during the three-layer coextrusion of cable production and the subsequent cable vulcanization process. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above problems existing in the prior art. The present invention provides a composition, a preparation method and an application thereof. This composition is applied to the semiconductive shielding material and has excellent anti-insulating yellowing characteristics.

[0004] The first aspect of the present invention provides a composition, which includes: a resin, conductive carbon black, a first antioxidant, a second antioxidant, and a crosslinking agent; Wherein, the mass content of metal elements in the conductive carbon black is not more than 10 ppm; Wherein, the first antioxidant is 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene and / or 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid; Wherein, the second antioxidant is bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite and / or pentaerythritol tetrakis(3-laurylthiopropionate).

[0005] Preferably, the mass ratio of the resin to the conductive carbon black is 1∶0.35 - 0.9.

[0006] Preferably, the weight ratio of the resin to the total amount of the first antioxidant and the second antioxidant is 1∶0.001 - 0.1.

[0007] Preferably, the mass content of metal elements in the conductive carbon black is not more than 5 ppm; and / or, the mass content of Fe elements in the conductive carbon black is not more than 2 ppm; and / or, the oil absorption value of the conductive carbon black is 90 - 350 mL / 100 g; and / or, the mass content of the ash of the conductive carbon black ≤ 0.01%.

[0008] The second aspect of the present invention provides a method for preparing the composition described in the first aspect above, wherein the method comprises the following steps: S1 Extruding and pelletizing a resin, conductive carbon black, a first antioxidant, a second antioxidant, and optionally a lubricating dispersant to obtain pellets; S2 Mixing the pellets with a crosslinking agent to obtain the composition.

[0009] The third aspect of the present invention provides the application of the composition described in the first aspect above or the composition prepared by the preparation method described in the second aspect above in a semiconductive shielding material.

[0010] The fourth aspect of the present invention provides the application of the composition described in the first aspect above or the composition prepared by the preparation method described in the second aspect above in the preparation of power cables.

[0011] By using a composition of conductive carbon black with a low metal element content in combination with a high-temperature resistant antioxidant as a semiconductive shielding material, the present invention not only has excellent anti-insulation yellowing characteristics, but also has excellent mechanical properties and conductive properties. The yellowness index of the insulation layer at the contact with the outer shield after cable extrusion is ≤4, and the electrical strength of the insulation layer is improved, ensuring good application of the material in the preparation of power cables. Detailed Embodiments

[0012] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values and individual point values of each range, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0013] The first aspect of the present invention provides a composition, which comprises: a resin, conductive carbon black, a first antioxidant, a second antioxidant, and a crosslinking agent; Wherein, the mass content of metal elements in the conductive carbon black is not more than 5 ppm; Wherein, the first antioxidant is 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene and / or 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid; Wherein, the second antioxidant is bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite and / or pentaerythritol tetrakis(3-laurylthiopropionate).

[0014] By using a composition of conductive carbon black with a metal element mass content not greater than 5 ppm and an antioxidant combined with specific components as a semiconductive shielding material, the present invention not only has excellent anti-insulation yellowing characteristics, but also has excellent mechanical properties and conductive properties. The dosage selection ranges of the resin, conductive carbon black, first antioxidant, second antioxidant, and crosslinking agent in the composition are relatively wide and can be adjusted according to the conventional dosages in the art.

[0015] Preferably, the mass ratio of the resin to the conductive carbon black is 1:0.35 - 0.9, such as 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, 1:0.7, 1:0.75, 1:0.8, 1:0.85, 1:0.9, or a range formed by any two ratios; further preferably, the mass ratio of the resin to the conductive carbon black is 1:0.45 - 0.8.

[0016] Preferably, the weight ratio of the resin to the total amount of the first antioxidant and the second antioxidant is 1:0.001 - 0.1, such as 1:0.005, 1:0.01, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09, 1:0.1, or a range formed by any two ratios; further preferably 1:0.005 - 0.05. Using the antioxidant dosage of the above preferred embodiment is more conducive to improving the high-temperature resistance of the cable during vulcanization and is conducive to ensuring that the composition of the present invention has excellent anti-insulation yellowing characteristics as a semiconductive shielding material.

[0017] The present invention has a relatively wide selection range for the relative dosage ratio of the first antioxidant and the second antioxidant. Preferably, the mass ratio of the first antioxidant to the second antioxidant is 1:(0.2 - 5), such as 1:0.2, 1:0.3, 1:0.5, 1:1, 1:1.3, 1:1.5, 1:1.8, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, or a range formed by any two ratios. More preferably, it is 1:(0.5 - 2), and even more preferably 1:(0.6 - 1.2). Using the dosage ratio of the two antioxidants of the above preferred embodiment is more conducive to improving the high-temperature resistance of the cable during vulcanization and is conducive to ensuring that the composition of the present invention has excellent anti-insulation yellowing characteristics as a semiconductive shielding material.

[0018] The present invention has no particular limitation on the resin, and it can be various polymers suitable for use as semiconductive shielding materials. Preferably, the resin is selected from at least one of ethylene-butyl acrylate copolymer, ethylene-vinyl acetate copolymer, and ethylene-octene copolymer, and more preferably ethylene-butyl acrylate copolymer.

[0019] The present invention does not particularly limit the source of the resin, which can be obtained through commercial purchase or prepared by any existing method.

[0020] According to the present invention, preferably, the melt index of the ethylene-butyl acrylate copolymer under a load of 2.16 kg at 190 °C is 6-25 g / 10 min, preferably 6-20 g / 10 min, and the mass content of butyl acrylate is 10-40%, preferably 13-30%.

[0021] According to the present invention, preferably, the melt index of the ethylene-vinyl acetate copolymer under a load of 2.16 kg at 190 °C is 2.5-25 g / 10 min, and the mass content of vinyl acetate is 12-33%.

[0022] According to the present invention, preferably, the melt index of the ethylene-octene copolymer under a load of 2.16 kg at 190 °C is 0.5-15 g / 10 min.

[0023] The resin adopting the above preferred embodiment is more conducive to the dispersion of conductive carbon black and antioxidant in the resin system.

[0024] In the present invention, the melt index is measured according to ASTM D1238 standard under the condition of 190 °C with a test load of 2.16 kg.

[0025] The present invention has a relatively wide selection range for the type and dosage of the crosslinking agent, and those skilled in the art can make an adaptive selection according to the adaptation of the type of the base resin, the requirements of conductive performance and mechanical performance.

[0026] Preferably, the crosslinking agent is selected from di-tert-butyl peroxide cumene and / or dicumyl peroxide, and further preferably di-tert-butyl peroxide cumene.

[0027] According to a preferred embodiment of the present invention, the mass ratio of the resin to the crosslinking agent is 1:(0.01-0.05), and further preferably 1:(0.01-0.03). Adopting this preferred embodiment is more conducive to improving the product performance.

[0028] The present invention does not particularly limit the source of the conductive carbon black, which can be commercially purchased or prepared by any existing preparation method, as long as the mass content of metal elements therein does not exceed 10 ppm, and further preferably the mass content of Fe element in the conductive carbon black does not exceed 5 ppm.

[0029] According to a preferred embodiment of the present invention, the mass content of metal elements in the conductive carbon black is not more than 5 ppm, more preferably not more than 2 ppm. Further preferably, the mass content of Fe element in the conductive carbon black is not more than 2 ppm. More preferably, the mass content of Fe element is not more than 1 ppm, and the total mass content of other metal elements is less than 1 ppm.

[0030] In the present invention, the metal element content of the conductive carbon black is measured by inductively coupled plasma atomic emission spectrometry.

[0031] The inventors of the present invention have found that by controlling the metal elements in the conductive carbon black and further controlling the amount of Fe element, it is more beneficial to improve the anti-insulation yellowing effect of the semi-conductive shielding material.

[0032] According to a preferred embodiment of the present invention, the oil absorption value of the conductive carbon black is 90 - 350 mL / 100 g, for example, 90 mL / 100 g, 100 mL / 100 g, 110 mL / 100 g, 120 mL / 100 g, 140 mL / 100 g, 160 mL / 100 g, 180 mL / 100 g, 200 mL / 100 g, 220 mL / 100 g, 250 mL / 100 g, 270 mL / 100 g, 300 mL / 100 g, or the range formed by any two point values. Further preferably, it is 90 - 200 mL / 100 g. Using the oil absorption value within this preferred range is more beneficial for the dispersion of the conductive carbon black in the resin system.

[0033] In the present invention, the oil absorption value of the conductive carbon black is measured by the DBP adsorption method.

[0034] According to a preferred embodiment of the present invention, the ash mass content of the conductive carbon black ≤ 0.01%. Using this preferred embodiment with highly clean carbon black is more beneficial for the dispersion of the carbon black in the resin system.

[0035] In the present invention, the ash mass content of the conductive carbon black is measured by thermogravimetric method.

[0036] The composition of the present invention may also optionally contain various additives required to enhance / adapt to its performance requirements, including but not limited to lubricating dispersants.

[0037] According to the present invention, preferably, the composition further comprises a lubricating dispersant. More preferably, the mass ratio of the resin to the lubricating dispersant is 1:(0.05 - 5), such as 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.3, 1:0.5, 1:1, 1:1.3, 1:1.5, 1:1.8, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5 or the range formed by any two ratios.

[0038] The present invention has a wide selection range for the type of the lubricating dispersant, as long as it can be beneficial to improving the dispersibility and lubricity of the material. Preferably, the lubricating dispersant is selected from at least one of polyethylene wax, oxidized polyethylene wax and ethylene bisstearamide.

[0039] According to a preferred embodiment of the present invention, by mass, in the composition, there are 80 - 100 parts of resin, 35 - 80 parts of conductive carbon black, 0.2 - 5 parts in total of the first antioxidant and the second antioxidant, 1 - 8 parts of lubricating dispersant, and 1 - 4 parts of crosslinking agent.

[0040] In the present invention, the first antioxidant, the second antioxidant, the lubricating dispersant and the crosslinking agent can all be obtained by commercial purchase.

[0041] The second aspect of the present invention provides a preparation method of the composition described in the first aspect above, wherein the method comprises the following steps: S1. Extrusion granulation is carried out on the resin, conductive carbon black, the first antioxidant, the second antioxidant and optionally the lubricating dispersant to obtain pellets; S2. The pellets are mixed with the crosslinking agent to obtain the composition.

[0042] In the method provided by the present invention, the selection and dosage range of each raw material are the same as those described in the first aspect, and will not be elaborated herein.

[0043] In the method provided by the present invention, "optionally" means that the lubricating dispersant can be added or not, and preferably it is added.

[0044] The present invention has no particular limitation on the manner of the extrusion granulation, and preferably it is carried out in a reciprocating single screw.

[0045] According to a preferred embodiment of the present invention, the temperature of the extrusion granulation in step S1 is 100 - 180 °C, such as 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, or the range formed by any two point values. In the present invention, there is no particular limitation on the specific operation of the extrusion granulation, and it can be carried out according to the conventional operation in the art. For example, it can be extruded successively at different temperatures (showing an increasing trend).

[0046] According to a preferred embodiment of the present invention, the temperature of the mixing in step S2 is 50 - 65 °C, preferably 50 - 60 °C.

[0047] The third aspect of the present invention provides the application of the composition described in the first aspect above or the composition prepared by the preparation method described in the second aspect above in a semiconductive shielding material.

[0048] The composition provided by the present invention can be directly used as a semiconductive shielding material or can be used as a semiconductive shielding material after processing.

[0049] The fourth aspect of the present invention provides the application of the composition described in the first aspect above or the composition prepared by the preparation method described in the second aspect above in the preparation of a power cable.

[0050] The present invention innovatively prepares a semiconductive shielding material by using conductive carbon black with a low metal content and a resin, enabling the semiconductive shielding material to have a preliminary anti-insulation yellowing effect. At the same time, a compound antioxidant is added to the formula system of the present invention, and the use of an efficient antioxidant combination enables the prepared cable to withstand a high temperature of over 300 °C during the vulcanization process, which is beneficial to ensuring that the composition of the present invention has excellent anti-insulation yellowing characteristics as a semiconductive shielding material. Specifically, after the cable is extruded and vulcanized, the yellowness index of the insulation layer at the contact with the outer shield is ≤ 4, preferably ≤ 3, indicating that the material of the present invention has an excellent anti-insulation yellowing effect during the cable processing; in addition, the average breakdown strength of the sliced insulation layer at the contact with the outer shield is increased by more than 10%, indicating that the semiconductive shielding material of the present invention improves the electrical strength of the insulation layer in contact with it; furthermore, the semiconductive shielding material of the present invention also has a relatively low volume resistivity and good mechanical properties, etc., so that it can be applied to the preparation of power cables with stable quality.

[0051] In a preferred embodiment of the present invention, the power cable is an AC cable.

[0052] The present invention will be described in detail below through examples.

[0053] In the following examples, the ethylene-butyl acrylate copolymer has a melt index of 7 g / 10 min at 190 °C under a load of 2.16 kg, the mass content of butyl acrylate is 17%, and it is purchased from Arkema, France, with the grade of 17BA07. The ethylene-vinyl acetate copolymer has a melt index of 20 g / 10 min at 190 °C under a load of 2.16 kg, the mass content of vinyl acetate is 20%, and it is purchased from Arkema, France, with the grade of 20-20. The ethylene-octene copolymer has a melt index of 5 g / 10 min at 190 °C under a load of 2.16 kg and is purchased from Dow Chemical, with the grade of 8200. Conductive carbon black A is purchased from Denka Co., Ltd., Japan, with the grade of Denkablack, the total metal element content is 1.7 ppm, the iron element content is 0.8 ppm, the total content of other metal elements is 0.9 ppm, the oil absorption value is 160 mL / 100 g, and the ash content is ≤0.007%. Conductive carbon black B is purchased from Orion Engineered Carbons, with the grade of kappa 100, the total metal element content is 3 ppm, the iron element content is 1.4 ppm, the total content of other metal elements is 1.6 ppm, the oil absorption value is 300 mL / 100 g, and the ash content is ≤0.003%. Conductive carbon black C is purchased from Imerys, with the grade of 260G, the total metal element content is 9 ppm, the iron element content is 5 ppm, the total content of other metal elements is 4 ppm, the oil absorption value is 190 mL / 100 g, and the ash content is ≤0.01%.

[0054] Example 1 This example provides an anti-insulation yellowing semi-conductive shielding material. By mass, the raw material composition of the semi-conductive shielding material includes: 100 parts of ethylene-butyl acrylate copolymer, 65 parts of conductive carbon black A, 0.8 part of tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene (antioxidant 330, the first antioxidant), 1 part of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite (antioxidant RC PEP 36, the second antioxidant), 1.2 parts of ethylene bisstearamide (lubricating and dispersing agent), and 1.8 parts of diisopropylbenzene peroxide (crosslinking agent).

[0055] The preparation method of the anti-insulation yellowing semi-conductive shielding material includes the following steps: S1. Add all other raw materials except the crosslinking agent into a reciprocating single-screw extruder according to the formula ratio to extrude and pelletize to obtain a premix; among them, the extrusion temperatures for the extrusion and pelletization are 100, 130, 145, and 150 °C in sequence; S2. Mix the premix obtained in step S1 with the crosslinking agent according to the formula ratio to obtain the anti-insulation yellowing semi-conductive shielding material; among them, the mixing temperature is 60 °C.

[0056] Example 2 This embodiment provides a semi-conductive shielding material resistant to insulating yellowing. By mass, the raw material composition of the semi-conductive shielding material includes: 80 parts of ethylene-butyl acrylate copolymer, 35 parts of conductive carbon black A, 0.5 part of 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid (antioxidant 3114, the first antioxidant), 0.3 part of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate (antioxidant RC PEP 36, the second antioxidant), 1 part of ethylene bisstearamide (lubricating and dispersing agent), and 1 part of di-tert-butyl peroxyisopropylbenzene (crosslinking agent).

[0057] The preparation method of the semi-conductive shielding material resistant to insulating yellowing includes the following steps: S1. Add all other raw materials except the crosslinking agent into a reciprocating single-screw extruder according to the formula ratio for extrusion granulation to obtain a premix; wherein, the extrusion temperatures for the extrusion granulation are 100, 130, 145, and 150 °C in sequence; S2. Mix the premix obtained in step S1 with the crosslinking agent according to the formula ratio to obtain the semi-conductive shielding material resistant to insulating yellowing; wherein, the mixing temperature is 60 °C.

[0058] Example 3 This embodiment provides a semi-conductive shielding material resistant to insulating yellowing. By mass, the raw material composition of the semi-conductive shielding material includes: 100 parts of ethylene-butyl acrylate copolymer, 80 parts of conductive carbon black A, 0.5 part of 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene (antioxidant 330, the first antioxidant), 0.5 part of 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid (antioxidant 3114, the first antioxidant), 0.8 part of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate (antioxidant RC PEP 36, the second antioxidant), 0.4 part of pentaerythritol tetrakis(3-laurylthiopropionate) (antioxidant 412S, the second antioxidant), 2 parts of ethylene bisstearamide (lubricating and dispersing agent), and 2 parts of di-tert-butyl peroxyisopropylbenzene (crosslinking agent).

[0059] The preparation method of the semi-conductive shielding material resistant to insulating yellowing includes the following steps: S1. Add all other raw materials except the crosslinking agent into a reciprocating single-screw extruder according to the formula ratio for extrusion granulation to obtain a premix; wherein, the extrusion temperatures for the extrusion granulation are 100, 130, 145, and 150 °C in sequence; S2. Mix the premix obtained in step S1 with the crosslinking agent according to the formula ratio to obtain the semi-conductive shielding material resistant to insulating yellowing; wherein, the mixing temperature is 60 °C.

[0060] Example 4 This example provides an anti-insulation yellowing semi-conductive shielding material. In terms of parts by mass, the raw material composition of the semi-conductive shielding material includes: 80 parts of ethylene-butyl acrylate copolymer, 80 parts of conductive carbon black A, 3 parts of antioxidant 330, 0.6 part of antioxidant 412S, 4 parts of ethylene bis-stearamide (lubricating dispersant), and 1 part of di-tert-butyl peroxyisopropylbenzene (crosslinking agent).

[0061] The preparation method of the anti-insulation yellowing semi-conductive shielding material includes the following steps: S1. Add all other raw materials except the crosslinking agent into a reciprocating single-screw extruder according to the formula ratio to extrude and granulate, obtaining a premix; wherein, the extrusion temperatures for the extrusion granulation are 100, 130, 145, and 150 °C in sequence.

[0062] S2. Mix the premix obtained in step S1 with the crosslinking agent according to the formula ratio to obtain the anti-insulation yellowing semi-conductive shielding material; wherein, the mixing temperature is 60 °C.

[0063] Example 5 This example provides an anti-insulation yellowing semi-conductive shielding material. In terms of parts by mass, the raw material composition of the semi-conductive shielding material includes: 100 parts of ethylene-vinyl acetate copolymer, 65 parts of conductive carbon black A, 0.8 part of 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene (antioxidant 330, the first antioxidant), 1 part of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite (antioxidant RC PEP 36, the second antioxidant), 1.2 parts of ethylene bis-stearamide (lubricating dispersant), and 1.8 parts of di-tert-butyl peroxyisopropylbenzene (crosslinking agent).

[0064] The preparation method of the anti-insulation yellowing semi-conductive shielding material includes the following steps: S1. Add all other raw materials except the crosslinking agent into a reciprocating single-screw extruder according to the formula ratio to extrude and granulate, obtaining a premix; wherein, the extrusion temperatures for the extrusion granulation are 100, 130, 145, and 150 °C in sequence; S2. Mix the premix obtained in step S1 with the crosslinking agent according to the formula ratio to obtain the anti-insulation yellowing semi-conductive shielding material; wherein, the mixing temperature is 60 °C.

[0065] Example 6 This embodiment provides a semi-conductive shielding material resistant to insulation yellowing. In terms of parts by mass, the raw material composition of the semi-conductive shielding material includes: 100 parts of ethylene-octene copolymer, 65 parts of conductive carbon black A, 0.8 part of 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl) mesitylene (antioxidant 330, the first antioxidant), 1 part of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite (antioxidant RC PEP 36, the second antioxidant), 1.2 parts of ethylene bisstearamide (lubricating and dispersing agent), and 1.8 parts of di-tert-butyl peroxyisopropylbenzene (crosslinking agent).

[0066] The preparation method of the semi-conductive shielding material resistant to insulation yellowing includes the following steps: S1. Add all the raw materials except the crosslinking agent into a reciprocating single-screw extruder according to the formula ratio for extrusion granulation to obtain a premix; wherein, the extrusion temperatures for the extrusion granulation are 100, 130, 145, and 150 °C in sequence. S2. Mix the premix obtained in step S1 with the crosslinking agent according to the formula ratio to obtain the semi-conductive shielding material resistant to insulation yellowing; wherein, the mixing temperature is 60 °C.

[0067] Example 7 According to the method of Example 2, the difference is that an equal mass of conductive carbon black B is used to replace conductive carbon black A.

[0068] Example 8 According to the method of Example 2, the difference is that an equal mass of conductive carbon black C is used to replace conductive carbon black A.

[0069] Comparative Example 1 According to Example 1, the difference is that high-purity conductive carbon black is not used, and ordinary conductive carbon black is used instead. The conductive carbon black grade is VXC68, purchased from Cabot, with a total metal element content of 26 ppm, an iron element content of 8 ppm, a total content of other metal elements of 18 ppm, an oil absorption value of 123 mL / 100 g, and an ash content of ≤0.2%.

[0070] Comparative Example 2 According to Example 1, the difference is that the raw material composition of the semi-conductive shielding material includes: 100 parts of ethylene-butyl acrylate copolymer, 65 parts of conductive carbon black, 1.8 parts of 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl) mesitylene (antioxidant 330, the first antioxidant), 1.2 parts of ethylene bisstearamide (lubricating and dispersing agent), and 1.8 parts of di-tert-butyl peroxyisopropylbenzene (crosslinking agent).

[0071] Comparative Example 3 According to Example 1, the difference is that the raw material composition of the semi-conductive shielding material includes: 100 parts of ethylene-butyl acrylate copolymer, 65 parts of conductive carbon black, 0.8 part of antioxidant 1010 (pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), 1 part of antioxidant DLTP (dilauryl thiodipropionate), 1.2 parts of ethylene bisstearamide (lubricating and dispersing agent), and 1.8 parts of di-tert-butyl peroxide cumene (crosslinking agent).

[0072] The anti-insulation yellowing semi-conductive shielding materials prepared in the above examples and comparative examples were subjected to the following performance tests. The specific results are shown in Table 1.

[0073] Among them, the test standard for tensile strength is GB / T1040.3-2006; The test standard for elongation at break is GB / T1040.3-2006; The test standard for volume resistivity at 20°C is GB / T3048.3-2007; The test standard for volume resistivity at 90°C is GB / T3048.3-2007; The test standard for impact embrittlement temperature is GB / T5470-2008; The test standard for heat aging test (130°C × 168h) is GB / T2951.12-2008; The test standard for tensile strength change rate is GB / T1040.3-2006; The test standard for elongation at break change rate is GB / T1040.3-2006; The test standard for the yellowing coefficient of the insulating layer at the contact between the outer screen and the insulation is GB / T 39822-2021; The test standard for the breakdown strength of the insulating layer at the contact between the outer screen and the insulation is GB / T 1408.1-2016.

[0074] Table 1

[0075] Continued Table 1

[0076] It can be seen from the results in the above table that when the composition provided by the present invention is applied to the semi-conductive shielding material, it has excellent anti-insulation yellowing performance and improved insulation breakdown strength.

[0077] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A composition, characterized in that, The composition comprises: a resin, conductive carbon black, a first antioxidant, a second antioxidant, and a crosslinking agent; wherein, the mass content of metal elements in the conductive carbon black is not more than 10 ppm; wherein, the first antioxidant is 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene and / or 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid; wherein, the second antioxidant is bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite and / or pentaerythritol tetrakis(3-laurylthiopropionate).

2. The composition according to claim 1, wherein, The mass ratio of the resin to the conductive carbon black is 1:0.35 - 0.9; and / or, the mass ratio of the resin to the crosslinking agent is 1:(0.01 - 0.05); and / or, the weight ratio of the resin to the total amount of the first antioxidant and the second antioxidant is 1:0.001 - 0.1; and / or, the mass ratio of the first antioxidant to the second antioxidant is 1:(0.2 - 5).

3. The composition according to claim 1, wherein, The mass ratio of the resin to the conductive carbon black is 1:0.45 - 0.8; and / or, the mass ratio of the resin to the crosslinking agent is 1:(0.01 - 0.03); and / or, the weight ratio of the resin to the total amount of the first antioxidant and the second antioxidant is 1:0.005 - 0.05; and / or, the mass ratio of the first antioxidant to the second antioxidant is 1:(0.5 - 2).

4. The composition according to claim 1, wherein, The resin is selected from at least one of ethylene-butyl acrylate copolymer, ethylene-vinyl acetate copolymer, and ethylene-octene copolymer; and / or, the crosslinking agent is selected from diisopropylbenzene peroxide tert-butyl and / or dicumyl peroxide; and / or, the mass content of Fe element in the conductive carbon black is not more than 5 ppm.

5. The composition according to claim 1, wherein, The resin is at least one of ethylene-butyl acrylate copolymer, ethylene-vinyl acetate copolymer, and ethylene-octene copolymer; The melt index of the ethylene-butyl acrylate copolymer under the action of a 2.16 kg load at 190 °C is 6 - 25 g / 10 min, and the mass content of butyl acrylate is 10 - 40%; The melt index of the ethylene-vinyl acetate copolymer under the action of a 2.16 kg load at 190 °C is 2.5 - 25 g / 10 min, and the mass content of vinyl acetate is 12 - 33%; The melt index of the ethylene-octene copolymer under the action of a 2.16 kg load at 190 °C is 0.5 - 15 g / 10 min.

6. The composition according to claim 1, wherein, the mass content of metal elements in the conductive carbon black is not more than 5 ppm; and / or, the mass content of Fe element in the conductive carbon black is not more than 2 ppm; and / or, the oil absorption value of the conductive carbon black is 90 - 350 mL / 100 g; and / or, the ash mass content of the conductive carbon black ≤ 0.01%.

7. The composition according to any one of claims 1-6, wherein, The composition further comprises a lubricating dispersant; The mass ratio of the resin to the lubricating dispersant is 1:(0.05 - 5).

8. The composition according to claim 7, wherein, the lubricating dispersant is selected from at least one of polyethylene wax, oxidized polyethylene wax, and ethylene bisstearamide.

9. A method for preparing the composition according to any one of claims 1-8, characterized in that, The method comprises the following steps: S1. Extrude and pelletize resin, conductive carbon black, the first antioxidant, the second antioxidant, and optionally a lubricating dispersant to obtain pellets; S2. Mix the pellets with a crosslinking agent to obtain the composition.

10. The method according to claim 9, wherein, The temperature of the extrusion pelletization in step S1 is 100 - 180 °C; And / or, the temperature of the mixing in step S2 is 50 - 65 °C.

11. Use of the composition according to any one of claims 1 - 8 or the composition prepared by the preparation method according to claim 9 or 10 in a semi-conductive shielding material.

12. Use of the composition according to any one of claims 1 - 8 or the composition prepared by the preparation method according to claim 9 or 10 in the preparation of power cables.

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