Anti-scorching agents and compositions, semiconductive shielding materials, their preparation methods and applications

Abstract

This invention relates to the field of power cable materials technology, and discloses an anti-scorching agent and composition, a semi-conductive shielding material, its preparation method, and its application. The anti-scorching agent comprises structural units provided by monomer A and structural units provided by monomer B; monomer A is 3-[(4-phenylaminophenyl)amino]-2-hydroxypropyl methacrylate, and monomer B is selected from trimethylolpropane trimethacrylate or pentaerythritol triacrylate; the molar ratio of monomer A to monomer B is 1:(2-4). This anti-scorching agent can achieve the anti-scorching effect of the semi-conductive shielding material and is beneficial for long-term extrusion.

Description

Technical Field

[0001] This invention relates to the field of power cable materials technology, specifically to an anti-scorching agent and composition, a semi-conductive shielding material, its preparation method, and its application. Background Technology

[0002] The power cable industry is a fundamental sector of the industrial base, a crucial supporting industry for the two pillar industries of the national economy—power and communications—and holds an extremely important position in the national economy. With the successive investment and construction of large-scale projects such as power grid transformation and ultra-high voltage (UHV) transmission, the power cable industry has developed rapidly, especially high-voltage and ultra-high-voltage submarine cables. As the only channel for transmitting electricity from offshore wind turbines to land, connecting onshore control centers and offshore substations, they are considered the lifeline of wind power projects and a vital component of offshore facilities. As an important part of the high-voltage cable structure, the semi-conductive shielding layer not only uniformly distributes the electric field within the insulation layer and eliminates air gaps at the conductor-insulation interface to reduce the damage caused by electrical stress concentration to the cable insulation layer, but also helps to suppress space charge injection and electrical treeing in the insulation layer, extending the cable's service life. The continuous increase in cable voltage levels places higher technical demands on the performance of the semi-conductive shielding layer, making it particularly important to maintain a perfect shielding layer during cable processing and manufacturing.

[0003] Therefore, the research on shielding materials needs to innovate and develop new anti-scorching agents and shielding material formulations to inhibit cross-linking reactions, and explore corresponding processing technologies, which has important research significance and value. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem of short scorch time of shielding materials in the prior art, and to provide an anti-scorch agent and composition, a semi-conductive shielding material, a preparation method thereof, and its application. The anti-scorch agent can achieve the anti-scorch effect of the semi-conductive shielding material and is beneficial for long-term extrusion.

[0005] To achieve the above objectives, a first aspect of the present invention provides an anti-scorching agent, wherein the anti-scorching agent comprises structural units provided by monomer A and structural units provided by monomer B; wherein monomer A is 3-[(4-phenylaminophenyl)amino]-2-hydroxypropyl methacrylate, and monomer B is selected from trimethylolpropane trimethacrylate or pentaerythritol triacrylate; wherein the molar ratio of monomer A to monomer B is 1:(2-4).

[0006] A second aspect of the present invention provides a method for preparing the aforementioned anti-scorching agent, wherein the preparation method includes: melt-blending monomer A and monomer B, granulating the obtained blend, and cooling the blend to obtain the anti-scorching agent;

[0007] The molar ratio of monomer A to monomer B is 1:(2-4).

[0008] A third aspect of the present invention provides an anti-scorching agent prepared by the aforementioned preparation method.

[0009] A fourth aspect of the present invention provides a composition for preparing a semiconductive shielding material, wherein the composition comprises an anti-scorching agent, a copolymer matrix, low-density polyethylene, a processing aid, and a crosslinking agent, wherein the processing aid comprises conductive carbon black, and wherein the anti-scorching agent is the aforementioned anti-scorching agent.

[0010] A fifth aspect of the present invention provides a method for preparing a semiconductive shielding material using the aforementioned composition, wherein the method comprises:

[0011] (S1) The aforementioned anti-scorching agent, copolymer matrix, low-density polyethylene and processing aid are brought into contact and mixed.

[0012] (S2) The mixture from step (S1) is extruded and granulated to obtain a premix;

[0013] (S3) After mixing the crosslinking agent and the premixed material, the mixture is cooled to obtain a semiconductive shielding material.

[0014] The sixth aspect of the present invention provides a semiconductive shielding material prepared by the method described above.

[0015] The seventh aspect of the present invention provides an application of the aforementioned semiconductive shielding material in submarine cables.

[0016] The beneficial effects of the present invention through the above technical solution are as follows:

[0017] (1) In the anti-scorching agent of the present invention, the alkenyl group on monomer A is used as a grafting functional group, and the carbonyl and amino groups are used as deep trapping groups. They can be used as the first functional grafting monomer to introduce holes and electron traps and enhance antioxidant properties. Monomer B has three carbonyl groups with deep trapping functions and three vinyl groups for grafting reactions. As the second functional grafting monomer, it introduces electron traps to assist monomer A in grafting onto the macromolecule. Therefore, some vinyl groups in monomer B, which has certain crosslinking aid functions, are used to assist the grafting reaction between monomer A and the macromolecule, which can slow down the crosslinking reaction and increase the anti-scorching properties.

[0018] (2) Furthermore, the present invention ensures the rationality of crosslinking reaction kinetics by adding low-density polyethylene to raw materials such as copolymer matrix and co-grafting modification with the anti-scorching agent of the present invention, and does not affect the manufacturing of cable. At the same time, it enhances the heat and oxygen aging resistance, realizes the anti-scorching effect of semiconductive shielding material, and is conducive to long-term extrusion. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating the mechanism by which PrMA / TMPTMA synergistic grafting exhibits anti-scorching properties;

[0020] Figure 2 This is a schematic flowchart of the preparation method of the semiconductive shielding material provided by the present invention;

[0021] Figure 3 These are the pressure-time variation curves of the shielding materials with different formulations in Example 5 and Comparative Examples 1-5 during long-term extrusion;

[0022] Figure 4 Infrared image of the PrMA / TMPTMA shielding material prepared in Example 1 as an anti-scorching agent. Detailed Implementation

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] As previously stated, the first aspect of the present invention provides an anti-scorching agent, wherein the anti-scorching agent comprises a structural unit provided by monomer A and a structural unit provided by monomer B; wherein monomer A is 3-[(4-phenylaminophenyl)amino]-2-hydroxypropyl methacrylate, and monomer B is selected from trimethylolpropane trimethacrylate or pentaerythritol triacrylate.

[0025] The molar ratio of monomer A to monomer B is 1:(2-4).

[0026] According to the present invention, more preferably, the anti-scorching agent comprises structural units provided by the polar compound 3-[(4-phenylaminophenyl)amino]-2-hydroxypropyl methacrylate (PrMA) and structural units provided by the polar compound trimethylolpropane trimethacrylate (TMPTMA).

[0027] The inventors of this invention discovered that, using the anti-scorch agent of this invention, the alkenyl group on monomer A serves as a grafting functional group, while the carbonyl and amino groups serve as deep trapping groups. These groups act as the first functional graft monomer, introducing hole and electron traps and enhancing antioxidant properties. Monomer B, possessing three carbonyl groups with deep trapping functions and three vinyl groups for the grafting reaction, acts as the second functional graft monomer, introducing electron traps to assist monomer A in grafting onto the macromolecule. Therefore, some vinyl groups in monomer B, which have a certain crosslinking aid function, are used to assist the grafting reaction between monomer A and the macromolecule, slowing down the crosslinking reaction and increasing anti-scorch properties. The co-grafting system ensures the rationality of the crosslinking reaction kinetics and does not affect cable manufacturing. Simultaneously, it enhances resistance to heat and oxygen aging, achieving an anti-scorch effect for the semiconductive shielding material and facilitating long-term extrusion.

[0028] In this invention, it should be noted that "scorching" is an accumulation of the effects of heat and time on the shielding material. It is a premature vulcanization phenomenon that can cause difficulties in cable processing, impair the smoothness and flatness of the shielding layer surface and the shielding performance, and may even lead to uneven "scarring" of the shielding layer, affecting the long-term extrusion of cable production.

[0029] A second aspect of the present invention provides a method for preparing the aforementioned anti-scorching agent, wherein the preparation method includes: melt-blending monomer A and monomer B, granulating the obtained blend, and cooling the blend to obtain the anti-scorching agent;

[0030] The molar ratio of monomer A to monomer B is 1:(2-4).

[0031] According to the present invention, the preparation method does not require an initiator. The monomer A and the monomer B are mixed in a certain ratio and melt-mixed. Then, the obtained blend is granulated for later use, and after cooling, an anti-scorching agent is obtained.

[0032] According to the present invention, the conditions for melt blending include: a temperature of 100-120°C, a rotation speed of 50-70 rpm, and a time of 10-15 min; preferably, the conditions for melt blending include: a temperature of 105-115°C, a rotation speed of 55-65 rpm, and a time of 12-13 min.

[0033] A third aspect of the present invention provides an anti-scorching agent prepared by the preparation method described above.

[0034] A fourth aspect of the present invention provides a composition for preparing a semiconductive shielding material, wherein the composition comprises an anti-scorching agent, a copolymer matrix, low-density polyethylene, a processing aid, and a crosslinking agent, wherein the processing aid comprises conductive carbon black, and wherein the anti-scorching agent is the aforementioned anti-scorching agent.

[0035] In this invention, preferably, the anti-scorching agent is a mixed additive of TMPTMA and PrMA with synergistic grafting effect; the crosslinking agent is diisopropyl peroxide (DCP). Since TMPTMA has the function of a crosslinking aid, the amount of DCP needs to be reduced when adding TMPTMA in order to coordinate the crosslinking reaction kinetics of the material.

[0036] Furthermore, this invention modifies raw materials such as copolymer matrices by adding low-density polyethylene and synergistically grafting it with a specific anti-scorching agent, such as... Figure 1 As shown, Figure 1 This diagram illustrates the mechanism by which PrMA / TMPTMA co-grafting exhibits anti-scorch properties. In this model, the vinyl groups on PrMA serve as functional groups for the grafting reaction, while the carbonyl and amino groups act as deep trapping groups. These groups act as the first functional grafting monomers, introducing hole and electron traps and enhancing antioxidant properties. TMPTMA possesses three carbonyl groups with deep trapping capabilities and three vinyl groups for the grafting reaction, acting as the second functional grafting monomers to introduce electron traps and assist PrMA grafting onto macromolecules. Therefore, some vinyl groups in TMPTMA, which possess certain crosslinking aid functions, are used to assist the grafting reaction between PrMA and macromolecules, slowing down the crosslinking reaction and increasing anti-scorch properties. The co-grafting system ensures the rationality of the crosslinking reaction kinetics and does not affect cable manufacturing. Simultaneously, it enhances resistance to heat and oxygen aging, achieving anti-scorch effects in semiconductive shielding materials and facilitating long-term extrusion.

[0037] According to the present invention, the vinyl acetate content in the copolymer matrix is ​​15-45 wt%, and the melt index is 3-50 g / 10 min at 190°C and 2.16 kg.

[0038] According to the present invention, the melt index of the low-density polyethylene is 35-50 g / 10 min under the conditions of 190°C and 2.16 kg.

[0039] In this invention, the melt flow index is determined according to ASTM D1238 standard at 190°C with a test load of 2.16 kg.

[0040] According to the present invention, the copolymer matrix is ​​selected from one or more of ethylene-vinyl acetate copolymer (EVA), ethylene-butyl acrylate copolymer (EBA), ethylene-ethyl acrylate copolymer (EEA), and polypropylene (PP).

[0041] According to the present invention, the processing aid includes one or more of antioxidants, conductive carbon black, and lubricating dispersants.

[0042] According to the present invention, the antioxidant is selected from one or more of antioxidant AO-60, antioxidant HP-10, antioxidant 168, antioxidant 300, antioxidant 1010, antioxidant 1024, antioxidant 1035, antioxidant 1076 and antioxidant DSTP, and a mixture thereof.

[0043] According to the present invention, the conductive carbon black has an average particle size of 30-60 nm and a BET specific surface area of ​​200-400 m². 2 / g, iodine absorption value is 65-75mg / g, oil absorption value is 140-200cc / 100g.

[0044] According to the present invention, the lubricating dispersant is selected from one or more of polyethylene wax, polypropylene wax, EVA wax, erucamide, and oleamide.

[0045] According to the present invention, the crosslinking agent is selected from one or more of dicumyl peroxide, di-tert-butyl cumyl peroxide, triallyl isocyanurate, vinyltrimethoxysilane, vinyltriethoxysilane, dibutyltin dilaurate, and triallyl cyanurate.

[0046] According to the present invention, the composition comprises:

[0047] The anti-scorching agent is 0.1-4 parts;

[0048] The copolymer matrix is ​​60-100 parts;

[0049] 5-35 parts of the low-density polyethylene;

[0050] The antioxidant is 0.2-1.5 parts;

[0051] The conductive carbon black is 45-90 parts;

[0052] The lubricating dispersant is 1-10 parts;

[0053] The crosslinking agent is 0.5-3 parts.

[0054] Preferably, the composition comprises:

[0055] The anti-scorching agent is 0.5-4 parts;

[0056] The copolymer matrix is ​​70-90 parts;

[0057] 15-30 parts of the low-density polyethylene;

[0058] The antioxidant is 0.6-1.2 parts;

[0059] The conductive carbon black is 50-75 parts;

[0060] The lubricating dispersant is 4-8 parts;

[0061] The crosslinking agent is 1-2 parts.

[0062] More preferably, the composition comprises:

[0063] 0.8 parts of the anti-scorching agent;

[0064] 80 parts of the copolymer matrix;

[0065] 25 parts of the low-density polyethylene;

[0066] One part of the antioxidant;

[0067] 60 parts of the conductive carbon black;

[0068] The lubricating dispersant is 6 parts;

[0069] The crosslinking agent is 1.2 parts.

[0070] In this invention, it should be noted that "parts" are equivalent to "parts by weight".

[0071] A fifth aspect of the present invention provides a method for preparing a semiconductive shielding material using the aforementioned composition, wherein the method comprises:

[0072] (S1) The aforementioned anti-scorching agent, copolymer matrix, low-density polyethylene and processing aid are brought into contact and mixed.

[0073] (S2) The mixture from step (S1) is extruded and granulated to obtain a premix;

[0074] (S3) After mixing the crosslinking agent and the premixed material, the mixture is cooled to obtain a semiconductive shielding material.

[0075] According to the present invention, in step (S1), the mixing conditions include: mixing at 100-120°C for 10-15 min, preferably mixing at 105-115°C for 11-13 min.

[0076] According to the present invention, in step (S3), the mixing conditions include mixing at 50-80°C for 5-15 minutes, preferably mixing at 70-75°C for 10-12 minutes.

[0077] According to a particularly preferred embodiment of the present invention, such as Figure 2 As shown, Figure 2 This is a schematic flowchart of a method for preparing a semiconductive shielding material provided by the present invention. The method for preparing a semiconductive shielding material includes:

[0078] (S1) The copolymer matrix, anti-scorching agent (e.g., PrMA / TMPTMA), low-density polyethylene (LDPE), conductive carbon black, antioxidant and lubricating dispersant are successively put into the internal mixer for mixing (internal mixing) at a mixing temperature of 100-120℃ for 10-15 minutes.

[0079] (S2) After the mixture is discharged, it is fed into an extruder for extrusion granulation to obtain a premix;

[0080] (S3) The premixed material and the crosslinking agent (DCP) of the formulation are mixed in a container at 50-80°C for 5-15 minutes and then cooled to obtain a semiconductive shield (anti-scorching shielding material).

[0081] This invention simplifies the production process and makes the preparation method simpler by directly adding an anti-scorching agent to the raw materials and mixing them in an extruder, without the need to prepare a scorching inhibitor masterbatch in advance.

[0082] The sixth aspect of the present invention provides a semiconductive shielding material prepared by the method described above.

[0083] According to the present invention, the scorching time of the semiconductive shielding material at 110°C is 5-7 min, preferably 6.5-7 min.

[0084] The seventh aspect of the present invention provides an application of the aforementioned semiconductive shielding material in submarine cables.

[0085] According to the present invention, in the process of applying the aforementioned semiconductive shielding material to submarine cables, the synergistic grafting effect of different types of vinyl groups in PrMA / TMPTMA affects the chemical reaction of the crosslinking agent. The application conditions include: melting and blending the semiconductive shielding material in a torque rheometer at 100-120°C and 50-70 rpm; then pressing the obtained blend in a pressure plate curing machine at 100-120°C and 10-20 MPa; and completing the crosslinking and grafting reaction by pressing the mixture at 160-190°C and 10-20 MPa for 20-40 minutes.

[0086] In this invention, the semiconductive shielding material can be applied to high-voltage long-duration submarine cables.

[0087] In this invention, the semiconductive shielding material is preferably used for DC.

[0088] The present invention will be described in detail below through embodiments.

[0089] In the following examples and comparative examples:

[0090] The specific gravity parameter was measured according to the method in GB / T 1033.1-2008;

[0091] The tensile strength parameters were measured according to the method in GB / T 1040.2-2022;

[0092] The tensile strength change rate parameter was measured according to the method in GB / T 1040.2-2022;

[0093] The elongation at break parameter was measured according to the method in GB / T 1040.2-2022;

[0094] The elongation at break parameter was measured according to the method in GB / T 1040.2-2022;

[0095] The volume resistivity parameter was measured according to the method in GB / T 31838.2-2019;

[0096] The thermal extension parameters were measured according to the method in GB / T 2951.21-2008;

[0097] The permanent deformation parameters after cooling were measured according to the method in GB / T 2951.21-2008.

[0098] The scorch time was measured by the internal mixing system of a Hap torque rheometer at 110°C and 60 rpm.

[0099] Example 1

[0100] This embodiment is intended to illustrate the anti-scorching agent and semi-conductive shielding material prepared according to the present invention.

[0101] Preparation method of anti-scorching agent: Without the action of an initiator, monomer a (3-[(4-phenylaminophenyl)amino]-2-hydroxypropyl methacrylate) shown in formula (A) and monomer b (trimethylolpropane trimethacrylate) shown in formula (B) are mixed at a molar ratio of 1:3 and melt-mixed at 110°C and 60 rpm; then, the obtained blend is granulated for later use, and after cooling, the anti-scorching agent is obtained;

[0102] The resulting anti-scorching agent (PrMA / TMPTMA) comprises structural units provided by the monomer shown in formula (A) and structural units provided by the monomer shown in formula (B), with a molar ratio of 1:3; and the weight-average molecular weight of the anti-scorching agent is 200,000.

[0103] Formula (A);

[0104] Formula (B).

[0105] The composition for preparing the semiconductive shielding material includes: 0.1 parts of an anti-scorching agent (PrMA / TMPTMA), 100 parts of a copolymer matrix (EVA) (ethylene ester content of 20wt%, melt index of approximately 20g / 10min, such as EVA20-20), 35 parts of LDPE (melt index of approximately 20g / 10min, such as PE-500CA), and conductive carbon black (average particle size of 30-60nm, BET specific surface area of ​​200-400m²). 2 / g, iodine absorption value is 65-75mg / g, oil absorption value is 140-200cc / 100g, such as BP2000) 45 parts, antioxidant (1010) 0.2 parts, lubricating dispersant (EVA wax) 1 part, crosslinking agent (DCP) 3 parts.

[0106] The preparation method of the semiconductive shielding material for high-voltage submarine cables using the above-mentioned composition for preparing semiconductive shielding material includes the following steps:

[0107] (S1) The copolymer matrix, anti-scorching agent, low-density polyethylene, conductive carbon black, antioxidant and lubricating dispersant in the formula amount are successively put into the internal mixer for mixing. The mixing temperature is 110℃ and the time is 12 minutes.

[0108] (S2) After the mixture is discharged, it is fed into an extruder for extrusion granulation to obtain a premix;

[0109] (S3) The premixed material and the crosslinking agent of the formulation are mixed in a container at 70°C for 10 minutes and then cooled to obtain the product.

[0110] The resulting semiconductive shielding material was prepared for use (for high-voltage submarine cables).

[0111] Figure 4 Infrared spectrum of the PrMA / TMPTMA shielding material prepared in Example 1 as an anti-scorching agent; wherein the PrMA / TMPTMA shielding material enhances the 1650 cm⁻¹ of PrMA. -1 The shoulder-like position indicates more C=C stretching vibrations in the TMPTMA, especially at 3400 cm. -1 The position exhibits the unique NH bond stretching vibration in PrMA, successfully confirming that antioxidants are synergistically grafted onto the polymer chain in the shielding material with PrMA / TMPTMA as an anti-scorching agent.

[0112] Example 2

[0113] This embodiment is intended to illustrate the anti-scorching agent and semi-conductive shielding material prepared according to the present invention.

[0114] The anti-scorching agent and semi-conductive shielding material were prepared according to the same method as in Example 1, except that the composition of the semi-conductive shielding material was the same as in Example 1, but the specific component content (weight fraction) was different: 4 parts anti-scorching agent, 60 parts EVA, 5 parts LDPE, 90 parts conductive carbon black, 1.5 parts antioxidant, 10 parts lubricating dispersant, and 0.5 parts crosslinking agent; the specific preparation method was the same as in Example 1; the semi-conductive shielding material was prepared for use (for high-voltage submarine cables).

[0115] Example 3

[0116] This embodiment is intended to illustrate the anti-scorching agent and semi-conductive shielding material prepared according to the present invention.

[0117] The anti-scorching agent and semi-conductive shielding material were prepared according to the same method as in Example 1, except that the composition of the semi-conductive shielding material was the same as in Example 1, but the specific component contents (weight fractions) were different: 0.5 parts of anti-scorching agent, 90 parts of EVA, 15 parts of LDPE, 50 parts of conductive carbon black, 0.6 parts of antioxidant, 4 parts of lubricating dispersant, and 1 part of crosslinking agent; the specific preparation method was the same as in Example 1; the semi-conductive shielding material was prepared for use (for high-voltage submarine cables).

[0118] Example 4

[0119] This embodiment is intended to illustrate the anti-scorching agent and semi-conductive shielding material prepared according to the present invention.

[0120] The anti-scorching agent and semi-conductive shielding material were prepared according to the same method as in Example 1, except that the composition of the semi-conductive shielding material was the same as in Example 1, but the specific component contents (weight fractions) were different: 2 parts anti-scorching agent, 70 parts EVA, 30 parts LDPE, 75 parts conductive carbon black, 1.2 parts antioxidant, 8 parts lubricating dispersant, and 2 parts crosslinking agent; the specific preparation method was the same as in Example 1; the semi-conductive shielding material was prepared for use (for high-voltage submarine cables).

[0121] Example 5

[0122] This embodiment is intended to illustrate the anti-scorching agent and semi-conductive shielding material prepared according to the present invention.

[0123] The anti-scorching agent and semi-conductive shielding material were prepared using the same method as in Example 1, except that the composition of the semi-conductive shielding material was the same as in Example 1, but the specific component contents (weight fractions) were different: 0.8 parts anti-scorching agent, 80 parts EVA, 25 parts LDPE, 60 parts conductive carbon black, 1 part antioxidant, 6 parts lubricating dispersant, and 1.2 parts crosslinking agent; the specific preparation method was the same as in Example 1; the semi-conductive shielding material was prepared for use (for high-voltage submarine cables).

[0124] Example 6

[0125] The semiconductive shielding material was prepared using the same method as in Example 1, except that the "anti-scorching agent (PrMA / TMPTMA)" in Example 1 was replaced with aminoethyl methacrylate / pentaerythritol triacrylate (MAEMA / PETA) in a molar ratio of 1:3; and the weight-average molecular weight of the anti-scorching agent was 50,000.

[0126] Formula (A);

[0127] Formula (B).

[0128] The preparation method of the semi-conductive shielding material for high-voltage submarine cables using the composition for preparing semi-conductive shielding material is the same as in Example 1; the semi-conductive shielding material is prepared for use (for high-voltage submarine cables).

[0129] Example 7

[0130] The semiconductive shielding material was prepared using the same method as in Example 1, except that the preparation method of the anti-scorching agent in Example 1 was modified as follows: without the action of an initiator, PrMA and TMPTMA were mixed at a molar ratio of 1:6 and melt-mixed at 110°C and 60 rpm. Then, the obtained blend was granulated for later use, and after cooling, the anti-scorching agent was obtained.

[0131] The resulting anti-scorching agent (PrMA / TMPTMA) comprises the monomers shown in formula (A) and formula (B) in a molar ratio of 1:6; and the weight-average molecular weight of the anti-scorching agent is 250,000.

[0132] Formula (A);

[0133] Formula (B).

[0134] The preparation method of the semi-conductive shielding material for high-voltage submarine cables using the composition for preparing semi-conductive shielding material is the same as in Example 1; the semi-conductive shielding material is prepared for use (for high-voltage submarine cables).

[0135] Example 8

[0136] The semiconductive shielding material was prepared using the same method as in Example 1, except that the "anti-scorching agent (PrMA / TMPTMA)" in Example 1 was replaced with "3-[(4-phenylaminophenyl)amino]-2-hydroxypropyl methacrylate and TMPTMA" obtained by alkyl substitution, and the molar ratio was 1:3; and the weight average molecular weight of the anti-scorching agent was 250,000.

[0137] Formula (A);

[0138] Formula (B).

[0139] The preparation method of the semi-conductive shielding material for high-voltage submarine cables using the composition for preparing semi-conductive shielding material is the same as in Example 1; the semi-conductive shielding material is prepared for use (for high-voltage submarine cables).

[0140] Comparative Example 1

[0141] The anti-scorching agent and the semi-conductive shielding material were prepared using the same method as in Example 5, except that the composition for preparing the semi-conductive shielding material "did not contain the anti-scorching agent PrMA / TMPTMA".

[0142] Comparative Example 2

[0143] The anti-scorching agent and the semi-conductive shielding material were prepared using the same method as in Example 5, except that the anti-scorching agent in the composition for preparing the semi-conductive shielding material did not contain PrMA, but only TMPTMA.

[0144] Comparative Example 3

[0145] The anti-scorching agent and the semi-conductive shielding material were prepared using the same method as in Example 5, except that the anti-scorching agent in the composition for preparing the semi-conductive shielding material did not contain TMPTMA, but only PrMA.

[0146] In addition, long-term extrusion tests were conducted on the shielding materials in Example 5 and Comparative Examples 1-3. Long-term extrusion experiments were carried out on insulation materials with different formulations. The long-term extrusion test method used a single-screw extruder equipped with a front-end pressure sensor, with an extrusion temperature of 110°C and a rotation speed of 60 rpm. The change in extrusion pressure over time was studied, and the test results are as follows: Figure 3 As shown, Figure 3 The pressure-time curves of different shielding material formulations during long-term extrusion are shown. Example 5 (red pentagram line), using a novel anti-scorching optimal shielding material formulation, is compared with the shielding materials in Comparative Examples 1-5 during long-term extrusion. Figure 3 It can be seen that the shielding materials provided in Comparative Examples 1-5 exhibit large fluctuations in extrusion pressure during extrusion, resulting in a rapid increase in the slope of the corresponding fitting curves, which fails to reflect long-term extrusion performance. In contrast, the high-voltage submarine cable semiconductive shielding material provided in Example 5 shows small fluctuations in extrusion pressure and excellent long-term stability during long-term extrusion, significantly outperforming semiconductive shielding materials without anti-scorching agents PrMA / TMPTMA and those with only anti-scorching agents, demonstrating superior long-term extrusion stability.

[0147] Comparative Example 4

[0148] The semiconductive shielding material was prepared using the same method as in Example 1, except that the “anti-scorching agent (PrMA / TMPTMA)” in Example 1 was replaced with “bisphenol A phosphazene / hexaphenoxycyclotriphosphazene, N3P3(O-C6H4-C(CH3)2-C6H4-O)6 and N3P3(OPh)6, with a molar ratio of 1:3”.

[0149] The preparation method of the semi-conductive shielding material for high-voltage submarine cables using the composition for preparing semi-conductive shielding material is the same as in Example 1; the semi-conductive shielding material is prepared for use (for high-voltage submarine cables).

[0150] Comparative Example 5

[0151] The semiconductive shielding material was prepared using the same method as in Example 1, except that the phrase “the monomer shown in Formula (A) and the monomer shown in Formula (B) in Example 1, with a molar ratio of 1:3” was replaced with “the monomer shown in Formula (A) and the monomer shown in Formula (B), with a molar ratio of 3:1”.

[0152] The preparation method of the semi-conductive shielding material for high-voltage submarine cables using the composition for preparing semi-conductive shielding material is the same as in Example 1; the semi-conductive shielding material is prepared for use (for high-voltage submarine cables).

[0153] Application examples

[0154] The semi-conductive shielding granular mixtures prepared in Examples 1-8 and Comparative Examples 1-5 were melt-mixed in a torque rheometer at 110°C and 60 rpm. The resulting blends were then pressed into shape in a platen curing machine at 110°C and 15 MPa. After crosslinking and grafting reactions were completed by pressing the mixture at 175°C and 15 MPa for 30 minutes, plate samples were obtained, and their basic physicochemical properties were tested. The scorch time T10 was also tested in a torque rheometer mixing system at 110°C and 60 rpm; the results are shown in Table 1.

[0155] Table 1

[0156]

[0157] Table 1 (continued)

[0158]

[0159] Table 1 and Table 1 (continued) show the performance of the scorch-resistant semiconductive shielding materials for high-voltage cables obtained in Examples 1-8 and Comparative Examples 1-5. Under optimal formulation conditions, the scorch time of the semiconductive shielding material in Example 5 is significantly delayed, exhibiting the best scorch resistance performance.

[0160] 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 inventive concept, 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 considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An anti-scorching agent, characterized in that, The anti-scorching agent comprises structural units provided by monomer A and structural units provided by monomer B; wherein, monomer A is 3-[(4-phenylaminophenyl)amino]-2-hydroxypropyl methacrylate, and monomer B is selected from trimethylolpropane trimethacrylate or pentaerythritol triacrylate; The molar ratio of monomer A to monomer B is 1:(2-4).

2. The anti-scorching agent according to claim 1, wherein, The anti-scorching agent comprises structural units provided by 3-[(4-phenylaminophenyl)amino]-2-hydroxypropyl methacrylate and structural units provided by trimethylolpropane trimethacrylate.

3. The anti-scorching agent according to claim 1 or 2, wherein, The weight-average molecular weight of the anti-scorching agent is 100,000 to 400,000.

4. A method for preparing the anti-scorching agent according to any one of claims 1-3, characterized in that, The preparation method includes: melt blending monomer A and monomer B, granulating the obtained blend, and cooling it to obtain an anti-scorching agent; The molar ratio of monomer A to monomer B is 1:(2-4).

5. The preparation method according to claim 4, wherein, The conditions for melt blending include: a temperature of 100-120℃, a rotation speed of 50-70 rpm, and a time of 10-15 min.

6. An anti-scorching agent prepared by the preparation method according to claim 4 or 5.

7. A composition for preparing a semiconductive shielding material, characterized in that, The composition comprises an anti-scorching agent, a copolymer matrix, low-density polyethylene, a processing aid, and a crosslinking agent, wherein the processing aid comprises conductive carbon black, and the anti-scorching agent is the anti-scorching agent according to any one of claims 1-3 and 6.

8. The composition according to claim 7, wherein, At 190℃ and 2.16kg, the melt index of the low-density polyethylene is 35-50g / 10min; And / or, the copolymer matrix is ​​selected from one or more of ethylene-vinyl acetate copolymer, ethylene-butyl acrylate copolymer, ethylene-ethyl acrylate copolymer, and polypropylene; And / or, the processing aids further include antioxidants and / or lubricating dispersants; And / or, the crosslinking agent is selected from one or more of dicumyl peroxide, di-tert-butyl peroxide, triallyl isocyanurate, and triallyl cyanurate.

9. The composition according to claim 8, wherein, The composition comprises: The anti-scorching agent is 0.1-4 parts; The copolymer matrix is ​​60-100 parts; 5-35 parts of the low-density polyethylene; The antioxidant is 0.2-1.5 parts; The conductive carbon black is 45-90 parts; The lubricating dispersant is 1-10 parts; The crosslinking agent is 0.5-3 parts.

10. A method for preparing a semiconductive shielding material using the composition according to any one of claims 7-9, characterized in that, The method includes: (S1) The anti-scorching agent, copolymer matrix, low-density polyethylene and processing aid described in any one of claims 1-3 and 6 are brought into contact and mixed. (S2) The mixture from step (S1) is extruded and granulated to obtain a premix; (S3) After mixing the crosslinking agent and the premixed material, the mixture is cooled to obtain a semiconductive shielding material.

11. The method according to claim 10, wherein, In step (S1), the mixing conditions include mixing at 100-120°C for 10-15 minutes.

12. A semiconductive shielding material prepared by the method of claim 10 or 11.

13. The semiconductive shielding material according to claim 12, wherein, The scorching time of the semi-conductive shielding material at 110°C is 5-7 minutes.

14. The semiconductive shielding material according to claim 13, wherein, The scorching time of the semiconductive shielding material at 110°C is 6.5-7 minutes.

15. The application of the semiconductive shielding material according to any one of claims 12-14 in submarine cables.

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