Silane cross-linked semiconductive shielding material and preparation method and application thereof
Technical Field
The invention belongs to the field of wire and cable materials, and particularly relates to a silane cross-linked semiconductive shielding material, and a preparation method and application thereof.
Background
The shielding of the conductor and the insulation of the power cable mainly relieves the stress concentration of an electric field in the cable, eliminates the influence of conductor twisting, and improves the radial distribution of the electric field in the cable so as to improve the electric strength of the cable and directly or indirectly improve the service life of the cable.
Thermoplastic shielding materials are widely used in the current semi-conductive shielding materials due to their low cost and simple processing technology. The cross-linking type shielding material has better temperature resistance, the peroxide cross-linking type shielding material is mainly used at present, and the peroxide cross-linking type shielding material needs to pass through a cross-linking machine during cable production, so that the process is complex, the production efficiency is low, and the production cost is high.
The silane crosslinking semiconductive shielding material is more convenient to crosslink, so that the silane crosslinking semiconductive shielding material has the processing performance of a thermoplastic shielding material and the temperature resistance of the crosslinking material. However, the silane cross-linked semiconductive shielding materials in the prior art cannot obtain the expected performances such as temperature resistance level, processability, volume resistivity and the like.
Citation 1 discloses a silane crosslinking semiconductive inner shielding material and a preparation method thereof, wherein the silane crosslinking semiconductive inner shielding material is prepared by mixing a grafting material A and a catalysis material B in a mass ratio of 5-9: 1 and then crosslinking the mixture with warm water; wherein: the grafting material A comprises the following components in parts by weight: 50-100 parts of ethylene-vinyl acetate copolymer, 10-50 parts of polyethylene, 1-4 parts of silane, 0.2-1 part of initiator, 0.1-1 part of antioxidant and 5-10 parts of lubricant; the catalytic material B comprises the following components in parts by weight: 100 parts of ethylene-vinyl acetate copolymer, 80-95 parts of conductive filler, 10-20 parts of lubricant, 1-5 parts of dispersant, 0.5-3 parts of catalyst and 0.5-2 parts of antioxidant; ethylene-vinyl acetate copolymer, the VA content of which is 15-20, the melt flow rate is 2.3-7.5 g/10min (the test conditions are 190 ℃, 2.16kg, the same below); the melt flow rate of the polyethylene is 2-20 g/10 min.
Citation 2 discloses a silane crosslinking semiconductive shielding material, and a preparation method and application thereof, wherein the semiconductive shielding material is prepared by mixing a material A and a material B in a mass ratio of 2-5: 1 and then crosslinking in water; the raw materials of the material A comprise ethylene butyl acrylate copolymer, bimodal polyethylene, conductive carbon black, antioxidant, silane, initiator, lubricant and dispersant in parts by weight; the raw materials of the material B comprise bimodal polyethylene and a hydrolysis catalyst; the content of butyl acrylate in the ethylene butyl acrylate copolymer is 10-30%, and the melt index of the bimodal polyethylene is 0.1-20 g/10 min; preparation: respectively preparing a material A and a material B, and then crosslinking in water according to a mass ratio.
The silane-crosslinked semiconductive shielding materials obtained in the above cited documents 1 and 2 have poor overall properties.
Cited documents:
cited document 1: CN 109294050A
Cited document 2: CN 107868328A
Disclosure of Invention
Problems to be solved by the invention
In view of the above drawbacks of the prior art, an object of the present invention is to provide a silane crosslinked semiconductive shielding material that is more convenient to crosslink, and has excellent processability of a thermoplastic shielding material and excellent temperature resistance of a crosslinked material.
The second purpose of the invention is to provide a preparation method of the silane crosslinking type semi-conductive shielding material, which is simple and feasible and has easily obtained raw materials.
Means for solving the problems
The invention provides a silane crosslinking type semiconductive shielding material, wherein the silane crosslinking type semiconductive shielding material comprises a component A and a component B, and the mass ratio of the component A to the component B is 90-99.5: 10-0.5; wherein the content of the first and second substances,
the component A comprises: silane crosslinked polyethylene, conductive carbon black and an ethylene-octene copolymer;
the component B comprises: polyethylene and a silane crosslinking catalyst.
The silane crosslinking semiconductive shielding material comprises a component A, a component B and a component C, wherein the component A comprises 40-60% of silane crosslinking polyethylene, 20-40% of conductive carbon black and 10-20% of ethylene-octene copolymer by mass;
based on the total mass of the component B, the addition amount of the polyethylene is 95-99.9%, and the addition amount of the silane crosslinking catalyst is 0.1-5%; preferably, the polyethylene in the B component comprises one or a combination of two or more of linear low density polyethylene, medium density polyethylene and high density polyethylene.
According to the silane crosslinked semiconductive shielding material, the grafting ratio of the silane crosslinked polyethylene is 85-100%.
The silane cross-linked semiconductive shielding material according to the present invention, wherein the silane cross-linked polyethylene has a gel content of not less than 80 wt%, and the silane cross-linked polyethylene has a thermal elongation at 200 ℃ of not more than 20%.
According to the silane crosslinking type semiconductive shielding material of the present invention, the silane crosslinking catalyst includes one or both of dibutyltin dilaurate and benzenesulfonic acid.
The invention also provides a preparation method of the silane crosslinking semiconductive shielding material, wherein the preparation method comprises the steps of mixing the component A and the component B, molding and crosslinking.
The preparation method according to the present invention, wherein the preparation method comprises the steps of:
mixing the component A and granulating to obtain component A particles;
mixing the component B and granulating to obtain component B granules;
mixing the component A particles and the component B particles and then molding to obtain a molded body;
and crosslinking the formed body to obtain the silane crosslinking semiconductive shielding material.
The production method according to the present invention, wherein the crosslinking is carried out in water and/or water vapor.
The invention also provides an application of the silane crosslinking semiconductive shielding material prepared by the preparation method of the silane crosslinking semiconductive shielding material and/or the silane crosslinking semiconductive shielding material in preparation of overhead insulating materials of electric wires and cables.
The invention also provides a cable, wherein the cable comprises the silane crosslinking semiconductive shielding material and/or the silane crosslinking semiconductive shielding material prepared by the preparation method of the silane crosslinking semiconductive shielding material.
ADVANTAGEOUS EFFECTS OF INVENTION
The silane crosslinking semiconductive shielding material provided by the invention has the performances of higher temperature resistance level, better processing performance, lower volume resistivity and the like.
Furthermore, the preparation method of the silane crosslinking semiconductive shielding material is simple and easy to implement, the raw materials are easy to obtain, and the silane crosslinking semiconductive shielding material is suitable for mass production.
Detailed Description
The present invention will be described in detail below. The technical features described below are explained based on typical embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples.
Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present invention. It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In other instances, methods, means, devices and steps which are well known to those skilled in the art have not been described in detail so as not to obscure the invention.
It should be noted that:
in the present specification, the meaning of "may" or "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.
In the present specification, the numerical range represented by "numerical value a to numerical value B" means a range including the end point numerical value A, B.
All units used in the present invention are international standard units unless otherwise stated, and numerical values and numerical ranges appearing in the present invention should be understood to include errors allowed in industrial production.
In the present specification, reference to "some particular/preferred embodiments," "other particular/preferred embodiments," "embodiments," and the like, means that a particular element (e.g., feature, property, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.
< first aspect >
In < first aspect > of the present invention, there is provided a silane crosslinking type semiconductive shielding material comprising an a component and a B component, the mass ratio of the a component to the B component being 90-99.5: 10-0.5;
the component A comprises: silane crosslinked polyethylene, conductive carbon black and an ethylene-octene copolymer;
the component B comprises: polyethylene and a silane crosslinking catalyst.
When the mass ratio of the component A to the component B is 90-99.5:10-0.5, the silane crosslinked polyethylene, the conductive carbon black and the ethylene-octene copolymer can be contained in the component A due to the high content of the component A, and can be uniformly dispersed; the polyethylene in the component B is used as a silane crosslinking catalyst carrier, so that the performance is more stable, and the adaptability to equipment is better.
In some embodiments of the present invention, the silane-crosslinked semiconductive shielding material is formed by mixing the a-component and the B-component, molding, and crosslinking in water and/or water vapor. The component A and the component B are mixed and molded, and are crosslinked in water and/or water vapor, so that the crosslinking efficiency is higher and the cost is lower compared with the crosslinking in a high-temperature vulcanization pipeline.
The silane crosslinking semiconductive shielding material has uniform appearance color and texture, obvious powdery substances should not be among particles, the tensile strength and the elongation at break are excellent, the aging test can be met, the fracture rate at the impact embrittlement temperature is lower at-40 ℃, the thermal elongation performance is excellent, and the volume resistivity is small.
Silane crosslinked polyethylene
The component A of the silane crosslinking semiconductive shielding material contains silane crosslinking polyethylene. The silane crosslinked polyethylene of the present invention may be obtained by purchase or may be prepared by itself. Specifically, the silane crosslinked polyethylene comprises the following components based on the total mass of the silane crosslinked polyethylene:
polyethylene: 95.5 to 96.8 percent;
coupling agent: 3 to 4 percent;
a crosslinking agent: 0.2 to 0.5 percent;
and an optional antioxidant, wherein the addition amount of the antioxidant is 0.02-0.9%.
Specifically, the polyethylene is one or a combination of several of Linear Low Density Polyethylene (LLDPE), Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE) and Medium Density Polyethylene (MDPE).
The antioxidant may include one or a combination of two or more of N, N '-bis [ β (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyl ] hydrazine (antioxidant 1024), tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester (antioxidant 1010), 4' -thiobis (6-tert-butyl-3-methylphenol) (antioxidant 300), distearyl thiodipropionate (antioxidant DSTP), and dilauryl thiodipropionate (antioxidant DLTP).
The coupling agent may include a silane coupling agent, preferably including one or a combination of two or more of vinyltriethoxysilane (silane coupling agent A-151), vinyltrimethoxysilane (silane coupling agent A-171), and vinyl-tris (2-methoxyethoxy) silane (silane coupling agent A-172).
The crosslinking agent includes peroxide crosslinking agents such as: dicumyl peroxide.
Specifically, the method for preparing the silane crosslinked polyethylene of the present invention comprises a step of mixing the components of the silane crosslinked polyethylene. Specifically, the preparation method of the silane crosslinked polyethylene comprises the steps of fully mixing the components, adding a double screw, extruding and granulating to obtain the silane crosslinked polyethylene.
The invention can effectively retain the dispersibility and the conductivity of the conductive carbon black by using the silane crosslinked polyethylene as the carrier of the component A. If the polyethylene is used as a carrier to fill the conductive carbon black and then the silane grafting reaction is carried out, the dispersibility of the conductive carbon black is reduced, and the conductivity of the silane crosslinking type semiconductive shielding material is weakened.
In some specific embodiments of the present invention, the silane crosslinked polyethylene is added in an amount of 40% to 60% based on the total mass of the a component, and when the silane crosslinked polyethylene is added in an amount of 40% to 60%, both the crosslinking degree and the conductivity are suitable; if the amount of the silane crosslinked polyethylene added is less than 40%, the degree of crosslinking may be insufficient; if the silane crosslinked polyethylene is added in an amount of more than 60%, the conductivity may be poor.
In the present invention, the kind of the silane crosslinked polyethylene is not particularly limited, and may be silane crosslinked polyethylene commonly used in the art. In a preferred embodiment, the present invention uses a silane crosslinked polyethylene having a high graft ratio of 85 to 100%. The silane crosslinked polyethylene with high grafting ratio can ensure that the crosslinked silane crosslinked semiconductive shielding material has high crosslinking degree, aging resistance, better heat resistance and more reliable material performance.
In some embodiments of the invention, the silane crosslinked polyethylene has a gel content of not less than 80 wt%, and the silane crosslinked polyethylene has a thermal elongation at 200 ℃ of not more than 20%. The silane crosslinked polyethylene with high grafting ratio adopted by the invention has higher crosslinking degree and more reliable product performance.
In addition, the grafting ratio of the present invention is calculated in the following manner:
the grafting ratio was ═ 100% by mass [ grafted monomer mass/(grafted monomer mass + ungrafted monomer mass) ].
For example, if there is 1kg of polyethylene, 0.8kg is grafted and 0.2kg is ungrafted.
The grafting ratio was 80% to 80% based on [ mass of grafted monomer (0.8 kg)/(mass of grafted monomer (0.8kg) + mass of ungrafted monomer (0.2kg)) ]x100%.
Conductive carbon black
The A component of the silane crosslinking semiconductive shielding material also contains conductive carbon black. The conductive carbon black is a conductive carbon black which can form a three-dimensional net-shaped conductive path in an insulator (such as plastic) by utilizing the conductivity of the carbon black, so that the insulator product has a conductive function under the action of the conductive carbon black, thereby enabling the insulator material to have antistatic and conductive capabilities and effectively increasing the service performance and range of the product.
In some specific embodiments of the present invention, the conductive carbon black is added in an amount of 20% to 40% by mass based on the total mass of the a component. If the addition amount of the conductive carbon black is 20-40%, the crosslinking performance, the mechanical performance and the conductivity are excellent, and the conductive carbon black with lower cost can be adopted.
Ethylene-octene copolymer
Ethylene-octene copolymers (POE) have ideal single active sites, thus enabling precise control of the relative molecular mass distribution, comonomer content and its distribution on the main chain during polymerization, and thus enabling precise control of the physical-mechanical and processing properties of the polymer.
The component A of the silane crosslinking semiconductive shielding material also contains an ethylene-octene copolymer. In some specific embodiments of the present invention, the ethylene-octene copolymer is added in an amount of 10% to 20% based on the total mass of the a component. When the addition amount of the ethylene-octene copolymer is 10-20%, the material has strong toughness and excellent elongation at break; when the addition amount of the ethylene-octene copolymer is less than 10%, the toughness of the material is insufficient, and the elongation cannot meet the requirement. When the addition amount of the ethylene-octene copolymer is more than 20%, the toughness of the material is not increased any more.
In the present invention, the ethylene-octene copolymer has a melt flow index of 1 to 10g/10min measured at 190 ℃ under a 2.16kg load according to ASTM D1238-2004.
Polyethylene
The component B of the silane crosslinking semiconductive shielding material contains polyethylene, and the polyethylene is used as a carrier of a silane crosslinking catalyst. In some embodiments of the present invention, the polyethylene is added in an amount of 95 to 99.9% by mass of the total mass of the B component, and in particular, if the polyethylene is added in an amount of less than 95%, it is difficult to process the polyethylene.
Specifically, in component B of the present invention, the polyethylene comprises one or a combination of two or more of linear low density polyethylene, medium density polyethylene, and high density polyethylene.
Silane crosslinking catalyst
The component B of the silane crosslinking semiconductive shielding material of the present invention contains a silane crosslinking catalyst, and the type of the silane crosslinking catalyst is not particularly limited in the present invention, and may be a silane crosslinking catalyst commonly used in the art. As a preferred embodiment of the present invention, the silane crosslinking catalyst includes one or both of dibutyltin dilaurate and benzenesulfonic acid.
In some specific embodiments of the present invention, the silane crosslinking catalyst is added in an amount of 0.1 to 5% by mass based on the total mass of the B component. If the addition amount of the silane crosslinking catalyst is less than 0.1 percent, the catalytic effect is insufficient; if the amount of the silane crosslinking catalyst added is more than 5%, the catalytic effect is not increased any more, causing unnecessary waste.
The silane crosslinking semiconductive shielding material has the advantages of higher temperature resistance level, better processing performance, lower volume resistivity and the like.
< second aspect >
In < second aspect > of the present invention, < first aspect > there is provided a method for producing a silane crosslinked type semiconductive shield material, comprising the steps of mixing the a-component and the B-component, molding, and crosslinking.
Further, the preparation method comprises the following steps:
mixing the component A and granulating to obtain component A particles;
mixing the component B and granulating to obtain component B granules;
mixing the component A particles and the component B particles and then molding to obtain a molded body;
and crosslinking the formed body to obtain the semiconductive shielding material.
Specifically, the preparation method comprises the following steps:
preparing component A particles: weighing the raw materials according to the raw material formula, adding the raw materials into an internal mixer for uniform internal mixing, and extruding and granulating the internally mixed material mass to obtain A component particles;
preparing B component particles: respectively weighing polyethylene and silane crosslinking catalyst by a weight-loss solid scale and a weight-loss liquid scale, adding the weighed materials into a double-screw extruder, mixing, and granulating to obtain component B particles;
preparation of a molded body: mixing the component A and the component B in proportion, and performing extrusion molding to obtain a molded body;
a crosslinking step: and (3) placing the formed body in water and/or water vapor for crosslinking to obtain the silane crosslinking semiconductive shielding material.
Wherein, in the preparation process of the component A particles: the setting temperature of banburying is 130-150 ℃, the banburying temperature can be 140-180 ℃, and the banburying time is 2-5 hours.
In the preparation process of the component B particles: the extrusion temperature of the twin-screw is 130-220 ℃, and the residence time of the screw is 10-60 seconds.
In the crosslinking step: and (3) finishing crosslinking in water bath at 80-100 ℃ for 3-5 hours, wherein the crosslinking time is different under different temperatures and humidities.
Specifically, the component A and the component B are uniformly mixed according to a proportion, and are processed into a forming body by a cable extruder, and the forming body is hydrolyzed in water bath at the temperature of 80-100 ℃ for 3-5 hours to complete silane crosslinking; the silane cross-linked semiconductive shielding material after silane cross-linking has higher temperature resistance level and longer service life than the thermoplastic shielding layer.
< third aspect >
In the < third aspect >, the present invention provides a silane crosslinked semiconductive shielding material according to the < first aspect > and/or a silane crosslinked semiconductive shielding material prepared by the method for preparing a silane crosslinked semiconductive shielding material according to the < second aspect >, and the use of the silane crosslinked semiconductive shielding material in the preparation of an overhead insulation material for electric wires and cables.
< fourth aspect >
In < fourth aspect > of the present invention, there is provided an electric cable comprising the silane coupling type semiconductive shielding material according to < first aspect > and/or the silane coupling type semiconductive shielding material produced according to the production method of the silane coupling type semiconductive shielding material according to < second aspect >.
Examples
Embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
In the invention, the composition and preparation method of the silane crosslinked polyethylene with high grafting rate are as follows: based on the total mass of the silane crosslinked polyethylene,
linear low density polyethylene: 96.7 percent;
vinyltriethoxysilane (silane coupling agent A-151): 3 percent;
dicumyl peroxide: 0.3 percent.
Linear low-density polyethylene, vinyl triethoxysilane (silane coupling agent A-151) and dicumyl peroxide are respectively weighed by a weight-loss solid weighing scale, a weight-loss liquid weighing scale and a weight-loss powder weighing scale, and are added into a double-screw extruder according to the above proportions to be mixed, the temperature of the double-screw extruder is 130-140-100-180-190-200-220 ℃ in sequence, the screw is sheared for 2 minutes, after full grafting, the melt is put into a single-screw extruder to be granulated, and the silane crosslinked polyethylene is obtained.
The gel content of the silane crosslinked polyethylene is 85 wt%, the thermal elongation of the silane crosslinked polyethylene at 200 ℃ is 15%, and the grafting ratio of the silane crosslinked polyethylene is 93%.
Wherein, the detection method of JB/T10437 is adopted to detect the gel content and the thermal extension at 200 ℃, and the grafting rate is calculated by the following formula:
the grafting ratio was ═ 100% by mass [ grafted monomer mass/(grafted monomer mass + ungrafted monomer mass) ].
Conductive carbon black: manufacturers, Shanxi Yongdong chemical products, Inc.; type, carbon black 250;
ethylene-octene copolymer: manufacturers, the dow chemical industry; model number, 8200;
linear low density polyethylene: the manufacturer, China petrochemical company, Zhenhai refining chemical company; model 7042.
Example 1
The embodiment provides a silane cross-linked semiconductive shielding material, which comprises the following raw materials:
the component A comprises: based on the total mass of the component A, the raw material formula is as follows: 43% of silane crosslinked polyethylene with high grafting rate, 37% of conductive carbon black and 20% of ethylene-octene copolymer.
And B component: based on the total mass of the component B, the raw material formula is as follows: 99.5 percent of linear low-density polyethylene, 0.4 percent of dibutyltin dilaurate and 0.1 percent of benzene sulfonic acid.
The preparation method of the silane crosslinking type semi-conductive shielding material comprises the following steps:
preparing component A particles: weighing the raw materials according to the raw material formula, adding the raw materials into an internal mixer, wherein the set temperature of the internal mixer is 140 ℃, so that the internal mixing temperature is 150-;
preparing B component particles: respectively weighing linear low-density polyethylene and a silane crosslinking catalyst by a weight-loss solid scale and a weight-loss liquid scale, and then adding the weighed materials into a double-screw extruder for mixing and granulation; the extrusion temperature of the double screw is 150-160-170-180-190-200-210-220 ℃, the residence time of the screw is 60 seconds, and the component B particles are prepared;
mixing the component A particles and the component B particles according to the mass ratio of 97:3, and performing extrusion molding to obtain a molded body; wherein the temperature of the single screw extruder body for the cable is 100-130-160-180 ℃, and the temperature of the extruder head is 160-200-210 ℃. And then, putting the formed body in a water bath at 90 ℃ for 4 hours to complete crosslinking, thus obtaining the silane crosslinking semiconductive shielding material.
Example 2
The embodiment provides a silane cross-linked semiconductive shielding material, which comprises the following raw materials:
the component A comprises: based on the total mass of the component A, the raw material formula is as follows: 48% of high-grafting-rate silane crosslinked polyethylene, 37% of conductive carbon black and 15% of ethylene-octene copolymer.
And B component: based on the total mass of the component B, the raw material formula is as follows: 99.5 percent of linear low-density polyethylene and 0.5 percent of dibutyltin dilaurate.
The preparation method of the silane crosslinking type semi-conductive shielding material comprises the following steps:
preparing component A particles: weighing the raw materials according to the raw material formula, adding the raw materials into an internal mixer, wherein the set temperature of the internal mixer is 140 ℃, so that the internal mixing temperature is 150-;
preparing B component particles: after weighing linear low-density polyethylene and a silane crosslinking catalyst respectively by a weight-loss solid weighing scale and a weight-loss liquid weighing scale, adding the weighed materials into a double-screw extruder, mixing and granulating the materials at the double-screw extrusion temperature of between 150 and 160 and 170 and between 180 and 190 and between 200 and 210 and 220 ℃, and keeping the screw for 60 seconds to prepare component B particles;
mixing the component A particles and the component B particles according to the mass ratio of 97:3, and performing extrusion molding to obtain a molded body; wherein the temperature of a machine body of the single-screw extruder for the cable is 100-130-160-180 ℃, the temperature of a machine head is 160-200-210 ℃, and then the formed body is put in water bath at 90 ℃ for 4 hours to complete crosslinking, thus obtaining the silane crosslinking type semi-conductive shielding material.
Example 3
The embodiment provides a silane cross-linked semiconductive shielding material, which comprises the following raw materials:
the component A comprises: based on the total mass of the component A, the raw material formula is as follows: 53 percent of silane crosslinked polyethylene with high grafting rate, 37 percent of conductive carbon black and 10 percent of ethylene-octene copolymer.
And B component: based on the total mass of the component B, the raw material formula is as follows: 99.5 percent of linear low-density polyethylene, 0.3 percent of dibutyltin dilaurate and 0.2 percent of benzene sulfonic acid.
The preparation method of the silane crosslinking type semi-conductive shielding material comprises the following steps:
preparing component A particles: weighing the raw materials according to the raw material formula, adding the raw materials into an internal mixer, wherein the set temperature of the internal mixer is 140 ℃, so that the internal mixing temperature is 150-;
preparing B component particles: respectively weighing linear low-density polyethylene and a silane crosslinking catalyst by a weight-loss solid scale and a weight-loss liquid scale, and then adding the weighed materials into a double-screw extruder for mixing and granulation; extruding the double screws at the temperature of between 150 and 160 to 170 to 180 to 190 to 200 to 210 to 220 ℃ and keeping the screws for 60 seconds to prepare component B particles;
mixing the component A particles and the component B particles according to the mass ratio of 97:3, and performing extrusion molding to obtain a molded body; wherein the temperature of a machine body of the single-screw extruder for the cable is 100-130-160-180 ℃, the temperature of a machine head is 160-200-210 ℃, and then the formed body is put in water bath at 90 ℃ for 4 hours to complete crosslinking, thus obtaining the silane crosslinking type semi-conductive shielding material.
Example 4
The embodiment provides a silane cross-linked semiconductive shielding material, which comprises the following raw materials:
the component A comprises the following raw materials in percentage by mass: 55% of high-grafting-rate silane crosslinked polyethylene, 35% of conductive carbon black and 10% of ethylene-octene copolymer.
The component B comprises the following raw materials in percentage by mass: 99.5 percent of linear low-density polyethylene and 0.5 percent of dibutyltin dilaurate.
The preparation method of the silane crosslinking type semi-conductive shielding material comprises the following steps:
preparing component A particles: weighing the raw materials according to the raw material formula, adding the raw materials into an internal mixer, wherein the set temperature of the internal mixer is 140 ℃, so that the internal mixing temperature is 150-;
preparing B component particles: respectively weighing linear low-density polyethylene and a silane crosslinking catalyst by a weight-loss solid scale and a weight-loss liquid scale, and then adding the weighed materials into a double-screw extruder for mixing and granulation; extruding the double screws at the temperature of between 150 and 160 to 170 to 180 to 190 to 200 to 210 to 220 ℃ and keeping the screws for 60 seconds to prepare component B particles;
mixing the component A particles and the component B particles according to the mass ratio of 97:3, and performing extrusion molding to obtain a molded body; wherein the temperature of a machine body of the single-screw extruder for the cable is 100-130-160-180 ℃, the temperature of a machine head is 160-200-210 ℃, and then the formed body is put in water bath at 90 ℃ for 4 hours to complete crosslinking, thus obtaining the silane crosslinking type semi-conductive shielding material.
Comparative example 1
The embodiment provides a silane cross-linked semiconductive shielding material, which comprises the following raw materials:
the component A comprises the following raw materials in percentage by mass: 63% of silane crosslinked polyethylene with high grafting rate and 37% of conductive carbon black.
The component B comprises the following raw materials in percentage by mass: 99.5 percent of linear low-density polyethylene and 0.5 percent of dibutyltin dilaurate.
The preparation process was identical to example 1.
Comparative example 2
The embodiment provides a silane cross-linked semiconductive shielding material, which comprises the following raw materials:
the component A comprises the following raw materials in percentage by mass: 37% of conductive carbon black and 63% of ethylene-octene copolymer.
The component B comprises the following raw materials in percentage by mass: 99.5 percent of linear low-density polyethylene, 0.3 percent of dibutyltin dilaurate and 0.2 percent of benzene sulfonic acid.
The preparation process was identical to example 1.
And (3) performance testing:
the semiconductive shield materials obtained in examples 1 to 4 and comparative examples 1 to 2 described above were tested for basic properties and thermal elongation, and the results are shown in table 1.
Detection and judgment basis:
JB/T10738 and 2007 semiconductive shielding material for extrusion-coated insulated cable with rated voltage of 35kV and below
TABLE 1
As can be seen from table 1, the silane crosslinked semiconductive shielding materials of examples 1 to 4 of the present application have uniform appearance, color and texture, no obvious powdery substance between particles, excellent tensile strength and elongation at break, and can satisfy the aging test, and at-40 ℃, the impact embrittlement temperature cracking rate is low, and the thermal elongation performance is excellent, and the volume resistivity is small.
Comparative example 1, which does not contain the ethylene-octene copolymer, has a poor elongation at break of only 11%.
Comparative example 2, which does not contain silane crosslinked polyethylene, has too high a volume resistivity at 90 c and also has too high a volume resistivity at 90 c after the air oven heat aging test. In addition, comparative example 2 is inferior in hot elongation property.
Industrial applicability
The silane crosslinking semiconductive shielding material and the preparation method thereof can be industrially implemented.
The above examples of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.