A flame-retardant insulating polyethylene material for cables and its use in cables

Abstract

This invention provides a flame-retardant insulating polyethylene material for cables and its application in cables. The flame-retardant insulating polyethylene material for cables comprises the following components in parts by weight: 70-100 parts low-density polyethylene, 10-20 parts high-density polyethylene, 20-30 parts organic flame retardant, 15-25 parts modified inorganic flame retardant, and 1-10 parts additives. The modified inorganic flame retardant is obtained by reacting a silane coupling agent-modified inorganic flame retardant with itaconic anhydride-grafted polyethylene. This invention introduces the modified inorganic flame retardant into the polyethylene chain segment, effectively improving the compatibility between different components and enhancing the bonding effect between multiple substances. This results in a good synergistic effect, endowing the polyethylene material with strong mechanical properties, insulation properties, and flame-retardant properties, meeting the material performance requirements of the cable industry.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a flame-retardant insulating polyethylene material for cables and its application in cables. Background Technology

[0002] Polyethylene (PE) materials, due to their excellent electrical insulation properties, processing and molding performance, and cost advantages, have been widely used in the preparation of insulation layers for various types of cables. Currently, its applications cover many areas, including low-voltage building wiring, medium- and high-voltage power transmission, and cables for special applications, making it one of the indispensable core materials in modern cable manufacturing. With the rapid development of industries such as power, rail transportation, and new energy, the operating environment of cables is becoming increasingly complex, placing higher demands on the flame retardant properties, mechanical properties, and electrical stability of insulation materials. Especially in densely populated or critical environments such as high-rise buildings, subways, and data centers, flame retardancy, low smoke, and low toxicity have become core performance indicators for insulation materials.

[0003] To achieve flame retardant properties in polyethylene materials, current technologies often employ a synergistic approach by adding organic and inorganic flame retardants. Common inorganic flame retardants include antimony trioxide and aluminum hydroxide. Inorganic flame retardants typically possess excellent high-temperature resistance and good insulation properties, enhancing the material's heat resistance and insulation strength. When used in combination with organic flame retardants, they can achieve a synergistic improvement in both flame retardant and insulation performance. However, due to the high surface energy and strong polarity of inorganic powders, and the low surface energy of polyethylene (a non-polar polymer), there are significant compatibility issues between the two. These issues lead to the easy aggregation and uneven dispersion of inorganic flame retardants within the polyethylene matrix. This not only weakens the synergistic flame retardant effect but also significantly reduces the mechanical and processing properties of the polyethylene material, resulting in problems such as brittleness and decreased tensile strength. Furthermore, it affects the dielectric properties of the insulation layer, making it difficult to meet the stringent comprehensive performance requirements of high-end cables.

[0004] Currently, most methods for modifying inorganic particles involve using silane coupling agents. However, silane coupling agents containing polar groups are insufficient in improving the compatibility between particles and polyethylene. Although silane coupling agents containing long alkyl chains can improve dispersibility to some extent, they cannot fundamentally solve the interfacial bonding problem between inorganic powders and polyethylene matrix, resulting in limited improvement and difficulty in simultaneously enhancing the flame retardancy, insulation, and mechanical properties of the material.

[0005] In conclusion, a new technical solution is urgently needed to address the problems existing in the current technology. Summary of the Invention

[0006] To address the deficiencies and shortcomings of the existing technology, this invention provides a flame-retardant insulating polyethylene material for cables and its preparation method. This invention introduces modified inorganic flame retardants into polyethylene chain segments, effectively improving the compatibility between different components and enhancing the bonding effect between multiple substances, thus forming a good synergistic effect. This endows the polyethylene material with strong mechanical properties, insulation properties, and flame-retardant properties, meeting the material performance requirements of the cable industry.

[0007] One objective of this invention is to provide a flame-retardant insulating polyethylene material for cables, wherein the flame-retardant insulating polyethylene material for cables comprises the following components in parts by weight: 70-100 parts of low-density polyethylene 10-20 parts of high-density polyethylene 20-30 parts of organic flame retardant 15-25 parts of modified inorganic flame retardant 1-10 parts of auxiliary agent; The modified inorganic flame retardant is obtained by reacting an inorganic flame retardant modified with a silane coupling agent with itaconic anhydride-grafted polyethylene.

[0008] Furthermore, the organic flame retardant is selected from halogenated flame retardants or halogen-free flame retardants.

[0009] Furthermore, the inorganic flame retardant includes mica powder and antimony trioxide.

[0010] Furthermore, the silane coupling agent is selected from epoxy silane coupling agents.

[0011] Furthermore, the additive is selected from one or more of plasticizers, crosslinking agents, antioxidants, initiators, light stabilizers, lubricants, and toughening agents.

[0012] Furthermore, the toughening agent is carboxyl-terminated polybutadiene.

[0013] Another object of the present invention is to provide a method for preparing the above-mentioned flame-retardant insulating polyethylene material for cables, wherein the method for preparing the flame-retardant insulating polyethylene material for cables includes the following steps: S1. Blend the inorganic flame retardant and the silane coupling agent, and heat to react to obtain the intermediate product; S2. Itaconic anhydride, polyethylene and initiator are blended, added to an extruder and extruded into granules to obtain itaconic anhydride-grafted polyethylene; S3. The intermediate product and itaconic anhydride-grafted polyethylene are blended and heated to react, thereby obtaining a modified inorganic flame retardant. S4. The modified inorganic flame retardant and the remaining components are mixed evenly and added to an extruder to extrude and obtain flame-retardant insulating polyethylene material for cables.

[0014] Furthermore, in step S1, the temperature of the heating reaction is 50-100°C.

[0015] Furthermore, in step S2, the temperature of the extrusion granulation is 140-200℃.

[0016] Furthermore, in step S3, the temperature of the heating reaction is 120-150°C.

[0017] Another object of the present invention is to provide the application of the above-mentioned flame-retardant insulating polyethylene material for cables in cables.

[0018] The present invention has the following beneficial effects: This invention provides a flame-retardant insulating polyethylene material for cables, containing a modified inorganic flame retardant. This component is obtained by reacting mica powder with epoxy groups introduced by a silane coupling agent, antimony trioxide, and itaconic acid grafted onto polyethylene. The modified inorganic filler not only introduces active functional groups but also introduces polyethylene segments on its surface, which is beneficial for improving insulation performance and avoiding agglomeration due to strong polarity. It significantly improves affinity with the polyethylene system, resulting in a more uniform distribution and better interfacial bonding, thus fully exerting its insulation, reinforcement, and synergistic flame-retardant functions. Simultaneously, this invention uses a material with active groups as a toughening agent, which can crosslink with the modified inorganic flame retardant through terminal carboxyl groups. The modified inorganic particles act as bridges and compatibilizers, allowing the polar toughening agent to bind and integrate into the system, forming a flexible network crosslinked structure between particles, further improving the mechanical properties of the material. Therefore, the flame-retardant insulating polyethylene material of this invention not only ensures good insulation and flame-retardant performance but also possesses excellent mechanical properties, meeting the performance requirements of cable products and solving the technical problems faced in the prior art. Detailed Implementation

[0019] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0020] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0021] It should be understood that, except in any operational instance or otherwise indicated, the amounts or all figures representing ingredients used, for example, in the specification and claims, should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​varying according to the desired performance to be obtained according to the invention.

[0022] The following raw materials are used in the embodiments of the present invention: Low-density polyethylene is LDPE 100AC.

[0023] High-density polyethylene is HPA 020.

[0024] The organic flame retardant is chlorinated polyethylene CPE140B.

[0025] The inorganic flame retardant is mica powder and antimony trioxide in a mass ratio of 3:1.

[0026] The toughening agent is carboxyl-terminated polybutadiene (purchased from Zibo Qilong Chemical).

[0027] The lubricant is calcium stearate.

[0028] The antioxidant is antioxidant 1010.

[0029] In the embodiments of this invention, "parts" refers to parts by mass. Example 1

[0030] A flame-retardant insulating polyethylene material for cables, comprising the following components in parts by weight: 85 parts of low-density polyethylene 15 parts high-density polyethylene 25 parts organic flame retardant 18 parts of modified inorganic flame retardant 4 parts toughening agent 1 part lubricant 1.5 parts antioxidant; The preparation method of the flame-retardant insulating polyethylene material for cables includes the following steps: S1. Using a mixture of ethanol and water (ethanol:water = 4:1, m / m) as a solvent, an inorganic flame retardant and silane coupling agent KH560 (inorganic flame retardant:silane coupling agent KH560 = 1:0.6, m / m) were mixed, heated and stirred at 80°C for 4 h, filtered and dried to obtain the intermediate product. S2. Itaconic anhydride, low-density polyethylene and dicumyl peroxide are blended (itaconic anhydride:low-density polyethylene:dicumyl peroxide=3:100:0.5, m / m / m), and then extruded and granulated in a twin-screw extruder at 170°C to obtain itaconic anhydride-grafted polyethylene. S3. Using xylene as a solvent, the intermediate product and itaconic anhydride-grafted polyethylene (intermediate product: itaconic anhydride-grafted polyethylene = 5:1, m / m) are blended, heated to reflux, stirred and reacted for 4 h, and the solvent is removed to obtain the modified inorganic flame retardant. S4. According to the above-mentioned mass proportions, the modified inorganic flame retardant and the remaining components are mixed evenly and added to a twin-screw extruder, and extruded and granulated at 170-180°C to obtain flame-retardant insulating polyethylene material for cables. Example 2

[0031] A flame-retardant insulating polyethylene material for cables, comprising the following components in parts by weight: 70 parts of low-density polyethylene 12 parts high-density polyethylene 20 parts organic flame retardant 15 parts of modified inorganic flame retardant 3.5 parts toughening agent 0.8 parts lubricant Antioxidant 1.3 parts; The preparation method of the flame-retardant insulating polyethylene material for cables includes the following steps: S1. Using a mixture of ethanol and water (ethanol:water = 4:1, m / m) as a solvent, an inorganic flame retardant and silane coupling agent KH560 (inorganic flame retardant:silane coupling agent KH560 = 1:0.6, m / m) were mixed, heated and stirred at 80°C for 4 h, filtered and dried to obtain the intermediate product. S2. Itaconic anhydride, low-density polyethylene and dicumyl peroxide are blended (itaconic anhydride:low-density polyethylene:dicumyl peroxide=3:100:0.5, m / m / m), and then extruded and granulated in a twin-screw extruder at 170°C to obtain itaconic anhydride-grafted polyethylene. S3. Using xylene as a solvent, the intermediate product and itaconic anhydride-grafted polyethylene (intermediate product: itaconic anhydride-grafted polyethylene = 5:1, m / m) are blended, heated to reflux, stirred and reacted for 4 h, and the solvent is removed to obtain the modified inorganic flame retardant. S4. According to the above-mentioned mass proportions, the modified inorganic flame retardant and the remaining components are mixed evenly and added to a twin-screw extruder, and extruded and granulated at 170-180°C to obtain flame-retardant insulating polyethylene material for cables. Example 3

[0032] A flame-retardant insulating polyethylene material for cables, comprising the following components in parts by weight: 100 parts of low-density polyethylene 20 parts of high-density polyethylene 30 parts organic flame retardant 22 parts of modified inorganic flame retardant 5 parts toughening agent 1 part lubricant Antioxidant 1.6 parts; The preparation method of the flame-retardant insulating polyethylene material for cables includes the following steps: S1. Using a mixture of ethanol and water (ethanol:water = 4:1, m / m) as a solvent, an inorganic flame retardant and silane coupling agent KH560 (inorganic flame retardant:silane coupling agent KH560 = 1:0.6, m / m) were mixed, heated and stirred at 80°C for 4 h, filtered and dried to obtain the intermediate product. S2. Itaconic anhydride, low-density polyethylene and dicumyl peroxide are blended (itaconic anhydride:low-density polyethylene:dicumyl peroxide=3:100:0.5, m / m / m), and then extruded and granulated in a twin-screw extruder at 170°C to obtain itaconic anhydride-grafted polyethylene. S3. Using xylene as a solvent, the intermediate product and itaconic anhydride-grafted polyethylene (intermediate product: itaconic anhydride-grafted polyethylene = 5:1, m / m) are blended, heated to reflux, stirred and reacted for 4 h, and the solvent is removed to obtain the modified inorganic flame retardant. S4. According to the above-mentioned mass proportions, the modified inorganic flame retardant and the remaining components are mixed evenly and added to a twin-screw extruder, and extruded and granulated at 170-180°C to obtain flame-retardant insulating polyethylene material for cables.

[0033] Comparative Examples 1-2 are set up based on the embodiments: The difference between Comparative Example 1 and Example 1 is as follows: Steps S2-S3 are omitted, and the intermediate product is used as a modified inorganic flame retardant. Other components and preparation methods are the same as in Example 1.

[0034] The difference between Comparative Example 2 and Example 1 is as follows: Modify step S3 as follows: S3. Blend the intermediate product (itaconic anhydride) grafted with polyethylene at a mass ratio of 5:1 to obtain a modified inorganic flame retardant. Other components and preparation methods are the same as in Example 1.

[0035] Test case The flame-retardant insulating polyethylene materials for cables prepared in the examples and comparative examples were subjected to performance tests.

[0036] Test methods: Performance tests were conducted in accordance with standards such as GB / T 1040.3, GB / T 2406.2, UL-94, and GB / T 1410.

[0037] The test results are shown in Table 1.

[0038] Table 1 Performance Test Results

[0039] As shown in Table 1, the flame-retardant insulating polyethylene material of the examples exhibits excellent overall performance, ensuring good mechanical properties, flame retardancy, and insulation. Comparative Example 1 uses an epoxidized inorganic flame retardant as a component, which makes it difficult to improve the compatibility between the component and the polyethylene system. It still suffers from poor dispersion and bonding effects, and the toughening agent is difficult to integrate into the system to exert its toughening function, resulting in a significant decrease in overall performance. Comparative Example 2 directly blends the intermediate product and itaconic anhydride-grafted polyethylene. However, the two are only insufficiently adsorbed and cross-linked during final extrusion, resulting in less than ideal coating and bonding effects between different components. It is difficult to obtain a uniform and continuous integrated structure, and the performance is also lower than that of the examples.

[0040] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0041] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A flame retardant insulating polyethylene material for electrical cables, characterized in that, The flame-retardant insulating polyethylene material for cables comprises the following components in parts by weight: 70-100 parts of low-density polyethylene 10-20 parts of high-density polyethylene 20-30 parts of organic flame retardant 15-25 parts of modified inorganic flame retardant 1-10 parts of auxiliary agent; The modified inorganic flame retardant is obtained by reacting an inorganic flame retardant modified with a silane coupling agent with itaconic anhydride-grafted polyethylene.

2. The flame-retardant insulating polyethylene material for cables according to claim 1, characterized in that, The organic flame retardant is selected from halogenated flame retardants or halogen-free flame retardants.

3. The flame-retardant insulating polyethylene material for cables according to claim 1, characterized in that, The inorganic flame retardant includes mica powder and antimony trioxide.

4. The flame-retardant insulating polyethylene material for cables according to claim 1, characterized in that, The silane coupling agent is selected from epoxy silane coupling agents.

5. The flame-retardant insulating polyethylene material for cables according to claim 1, characterized in that, The additives are selected from one or more of plasticizers, crosslinking agents, antioxidants, initiators, light stabilizers, lubricants, and toughening agents.

6. The method for preparing the flame-retardant insulating polyethylene material for cables according to any one of claims 1-5, characterized in that, The preparation method of the flame-retardant insulating polyethylene material for cables includes the following steps: S1. Blend the inorganic flame retardant and the silane coupling agent, and heat to react to obtain the intermediate product; S2. Itaconic anhydride, polyethylene and initiator are blended, added to an extruder and extruded into granules to obtain itaconic anhydride-grafted polyethylene; S3. The intermediate product and itaconic anhydride-grafted polyethylene are blended and heated to react, thereby obtaining a modified inorganic flame retardant. S4. The modified inorganic flame retardant and the remaining components are mixed evenly and added to an extruder to extrude and obtain flame-retardant insulating polyethylene material for cables.

7. The method for preparing flame-retardant insulating polyethylene material for cables according to claim 6, characterized in that, In step S1, the temperature of the heating reaction is 50-100℃.

8. The method for preparing flame-retardant insulating polyethylene material for cables according to claim 6, characterized in that, In step S2, the temperature of the extrusion granulation is 140-200℃.

9. The method for preparing flame-retardant insulating polyethylene material for cables according to claim 6, characterized in that, In step S3, the temperature of the heating reaction is 120-150℃.

10. The use of the flame-retardant insulating polyethylene material for cables according to any one of claims 1-5 in cables.

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