Polyethylene composite material for preparing radially tearable cable sheath and optical cable

Abstract

The present application belongs to the technical field of cable sheath materials, and more specifically, relates to a polyethylene composite material and an optical cable for preparing radially tearable cable sheaths. The polyethylene composite material provided by the present application is obtained by extruding and granulating after mixing a polyethylene main body, an easy-tear inlay and a processing aid, wherein the easy-tear inlay includes polyamide, polyester and a toughening agent, and the weight ratio of the easy-tear inlay to the polyethylene main body is (0.05~0.4):1. The present application introduces an easy-tear inlay capable of forming a phase separation structure into the polyethylene main body and regulates the amount of the easy-tear inlay, so that the cable sheath prepared by using the above-mentioned polyethylene composite material has excellent axial tensile properties, radially easy tearing and good dimensional stability, can be torn in a radial straight line, has small deformation at the tearing point, and has neat tearing, can effectively protect the internal structure of the cable, and can provide convenient stripping performance during construction and maintenance, reducing the difficulty and cost of operation.

Description

Technical Field

[0001] The present application belongs to the technical field of cable sheath materials, and more specifically, relates to a polyethylene composite material and an optical cable for preparing a radially tearable cable sheath. Background Art

[0002] In the communications industry, optical cables are a crucial medium for information transmission, and their performance stability and reliability are crucial. As a crucial component of optical cables, the cable sheath must not only possess excellent waterproof, high-temperature, and corrosion-resistant properties to protect the cable's internal structure from environmental damage, but also be tear-resistant in specific application scenarios to facilitate installation, construction, and maintenance.

[0003] The basic types of polyethylene (PE) materials include low-density polyethylene (LDPE) and high-density polyethylene (HDPE). HDPE, with its high crystallinity, non-polarity, and thermoplastic properties, is a high-quality thermoplastic material. Tubular structures such as water supply and drainage pipes, cables, and optical cable sheaths manufactured using it offer excellent economic benefits, stable interfaces, high mechanical strength, and excellent insulation properties. Therefore, it is widely used in fields such as construction and communications. With the rapid development of communications technology, the application scenarios of optical cables are becoming increasingly diverse, and the requirements for sheath materials are also becoming increasingly stringent. In emergency repair and rapid deployment scenarios, the importance of easy-tear sheath materials is becoming increasingly prominent. However, the excellent mechanical properties of HDPE make cable and tube structures manufactured using it difficult to tear, exhibit large deformation at the tear site, and exhibit poor dimensional stability. This leads to certain difficulties in the installation, construction, maintenance, and disassembly of cable sheath products, limiting their application in cable products that require fast and convenient construction and maintenance.

[0004] Cable sheaths made from traditional polyethylene sheathing materials are difficult to strip directly (radial tear strength greater than 300N). These materials require a cable-stripping aid designed into the cable structure or the use of specialized tools. These stripping methods are complex, inefficient, costly, and difficult to operate, making them inconvenient to install, process, repair, and disassemble. To meet market demand for easy-to-tear PE cable sheaths, it is necessary to develop a polyethylene composite material suitable for preparing cable sheaths that exhibits excellent mechanical properties under axial tension, is easy to tear radially, exhibits good dimensional stability, and can tear radially with a clean tear and minimal deformation. Summary of the Invention

[0005] In response to the defects of the existing technology, the purpose of this application is to provide a polyethylene composite material and optical cable for preparing radially tearable cable sheaths, aiming to solve the problems of existing cable sheaths prepared with polyethylene composite materials, such as difficulty in radial stripping (radial tear strength greater than 300N), the need for tools, complex and difficult operation, large deformation at the tearing point, poor dimensional stability, and inability to tear along a radial straight line.

[0006] To achieve the above objectives, in a first aspect, the present application provides a polyethylene composite material for preparing a radially tearable cable sheath, which is obtained by mixing and kneading a polyethylene main body, an easy-tear inlay, and a processing aid, and then extruding and granulating.

[0007] The above-mentioned easy-to-tear inlay includes polyamide, polyester and a toughening agent, and the weight ratio of the easy-to-tear inlay to the polyethylene main body is (0.05~0.4):1.

[0008] Preferably, in the above-mentioned easy-to-tear inlay, the weight ratio of the above-mentioned polyamide to the polyester is 1:(0.5-2), and the added amount of the above-mentioned toughening agent is 1wt%-3wt% of the total weight of the above-mentioned polyamide and the above-mentioned polyester.

[0009] Preferably, the melting point of the polyamide is 170°C to 270°C.

[0010] Preferably, the polyamide is selected from one or more of nylon 6, nylon 66, nylon MXD-6, nylon 1010, nylon 11, nylon 12 and nylon 1212.

[0011] Preferably, the polyester is selected from one or more of polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate.

[0012] Preferably, the polyethylene main body has a number average molecular weight of 9,000 to 100,000 and is selected from one or more of high-density polyethylene, medium-density polyethylene and low-density polyethylene.

[0013] Further preferably, the above-mentioned polyethylene main body is composed of high-density polyethylene and low-density polyethylene, wherein the weight ratio of high-density polyethylene to low-density polyethylene is (1.5~5):1.

[0014] Preferably, the processing aids include one or more of a compatibilizer, an antioxidant, an anti-ultraviolet agent, a masterbatch, a heat stabilizer and an antistatic agent.

[0015] Preferably, the added amount of the processing aid is 1 wt% to 5 wt% of the polyethylene main body.

[0016] Preferably, the compatibilizer is a maleic anhydride compatibilizer, selected from one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted POE and maleic anhydride grafted SEBS.

[0017] Preferably, the antioxidant is selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant DLTDP and antioxidant 168.

[0018] Preferably, the anti-ultraviolet agent is selected from one or more of benzoate anti-ultraviolet agents and amine anti-ultraviolet agents.

[0019] In a second aspect, the present application provides a method for preparing the above-mentioned polyethylene composite material, comprising the following steps:

[0020] S1. Blending the polyamide, polyester, and toughening agent according to a ratio and granulating the mixture, so that the polyester and the polyamide undergo an ester-amide exchange reaction to obtain an easily tearable inlay;

[0021] S2. Mix the easy-to-tear inlay, the polyethylene main body, and the processing aid according to the ratio, knead the mixture, and then extrude and granulate the mixture, so that the easy-to-tear inlay forms a dispersed phase separation structure in the polyethylene main body, and dry the mixture to obtain a polyethylene composite material.

[0022] Preferably, in step S1, the blending speed is 100-300 rpm, and the blending time is 5-10 min.

[0023] Preferably, in step S1, the granulation temperature is higher than the melting point of the polyamide, and the temperature difference is 10°C to 20°C.

[0024] Preferably, in step S2, the rotation speed of the mixing and kneading is 100-800 rpm, and the mixing and kneading time is 5-20 min.

[0025] Preferably, in step S2, the temperature of the extrusion granulation is within the range of ±5°C of the melting point of the polyamide.

[0026] In a third aspect, the present application provides a radially tearable cable sheath comprising the above-mentioned polyethylene composite material.

[0027] In a fourth aspect, the present application provides an optical cable comprising the above-mentioned cable sheath.

[0028] In general, the above technical solutions conceived by this application have the following technical advantages compared with the existing technologies:

[0029] (1) The polyethylene composite material provided in the present application is obtained by mixing and kneading a polyethylene main body, an easy-tear inlay and a processing aid, and then extruding and granulating the mixture. The easy-tear inlay includes polyamide, polyester and a toughening agent, and the weight ratio of the easy-tear inlay to the polyethylene main body is (0.05~0.4):1. The present application introduces an easy-tear inlay that can form a phase separation structure into the polyethylene main body, and regulates the ratio of the easy-tear inlay to the polyethylene main body, so that the cable sheath prepared by using the above polyethylene composite material has excellent axial tensile properties, is easy to tear in the radial direction, and has good dimensional stability. It can be torn in a straight line along the radial direction, with small deformation at the tearing point and neat tearing. The cable sheath prepared by using the polyethylene composite material provided in the present application can effectively protect the internal structure of the cable, and at the same time can provide convenient stripping performance during construction and maintenance, reducing the difficulty and cost of operation.

[0030] (2) This application regulates the ratio of polyamide, polyester and toughening agent in the tearable inlay, so that the polyamide and polyester can fully undergo ester-amide exchange reaction to produce block copolymers, and at the same time adjusts the number average molecular weight of the polyethylene main body so that the block copolymer is uniformly dispersed in the polyethylene main body under the action of the processing aid compatibilizer, forming a phase separation structure (i.e., tearable inlay). When using the above-mentioned polyethylene composite material to prepare a radially tearable cable sheath, the tearable inlay can maintain excellent tensile properties of the cable sheath along the processing direction (axial direction) during the extrusion process, with a tensile strength of 15~25MPa; the defects formed by the tearable inlay in the perpendicular axis direction (radial direction) can reduce the difficulty of radial tearing, so that the cable sheath has the characteristic of radially easy tearing, with a radial tear strength of 50~200N. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 1 is a schematic flow chart of a method for preparing a polyethylene composite material provided in an embodiment of the present application;

[0032] Figure 2 This is a radial tearing picture of the cable sheath sample prepared in Example 1 of the present application;

[0033] Figure 3 This is a radial tearing picture of the cable sheath sample prepared in Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0035] In the description of this application, it should be understood that the term "and / or" describes an association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The symbol " / " herein indicates that the associated objects are in an "or" relationship, for example, A / B means either A or B.

[0036] In the specification and claims of this application, the terms "first" and "second" and so on are used to distinguish different objects rather than to describe the specific order of objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0037] In the description of the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0038] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more.

[0039] For cable sheaths, the term "axial" refers to the direction along the length of the cable sheath, and the term "radial" refers to the direction perpendicular to the axial direction of the cable sheath and outward from the center of the cable.

[0040] The cable sheath made of traditional polyethylene sheathing material usually has a radial tear strength greater than 300N, making it difficult to directly peel. The radial tearing performance is poor, and it is necessary to design a cable opening aid in the cable structure, or use a special tool for peeling. There are problems such as complex preparation steps, low efficiency, high cost, complex operation, and high difficulty in operation. It is not convenient for installation, processing, maintenance and disassembly. Based on this, the application provides a polyethylene composite material for preparing radial tearing cable sheath, which is obtained by mixing and kneading a polyethylene main body, an easy-to-tear inlay and a processing aid, and then extruding and granulating.

[0041] The easy-to-tear inlay comprises polyamide, polyester and a toughening agent, and the weight ratio of the easy-to-tear inlay to the polyethylene main body is (0.05-0.4):1.

[0042] In some embodiments, the polyethylene main body has a number average molecular weight of 9,000 to 100,000 and is selected from one or more of high-density polyethylene, medium-density polyethylene, and low-density polyethylene.

[0043] In some embodiments, the above-mentioned polyethylene main body is composed of high-density polyethylene and low-density polyethylene, wherein the weight ratio of high-density polyethylene to low-density polyethylene is (1.5~5):1, which can control the number average molecular weight of the polyethylene main body within an appropriate range, thereby regulating the mechanical strength of the cable sheath prepared using the polyethylene composite material.

[0044] In some embodiments, the number average molecular weight of the high-density polyethylene is 40,000-300,000, and the density is 0.940-0.964 g / cm 3 .

[0045] In some embodiments, the number average molecular weight of the low-density polyethylene is 5000-20000, and the density is 0.910-0.930 g / cm 3 .

[0046] In some embodiments, in the tearable inlay, the weight ratio of the polyamide to the polyester is 1:(0.5-2), preferably 1:(0.5-1.5), so that the polyamide and the polyester can fully undergo ester-amide exchange reaction during processing.

[0047] In some embodiments, in the tearable inlay, the amount of the toughening agent added is 1 wt% to 3 wt% of the total weight of the polyamide and the polyester.

[0048] In some embodiments, the melting point of the polyamide is 170°C to 270°C.

[0049] In some embodiments, the polyamide is selected from one or more of nylon 6, nylon MXD-6, nylon 66, nylon 1010, nylon 11, nylon 12 and nylon 1212.

[0050] In some embodiments, the polyester is selected from one or more of polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT).

[0051] In some embodiments, the toughening agent is a non-crosslinking toughening agent, including a non-crosslinking non-reactive toughening agent (also known as a non-active toughening agent) and / or a non-crosslinking reactive toughening agent (also known as an active toughening agent).

[0052] It is understood that this application does not specifically limit the specific types of the above-mentioned toughening agents. In some embodiments, the above-mentioned non-crosslinking, non-reactive toughening agents include, but are not limited to, EMA (ethylene-methyl acrylate copolymer), EBA (ethylene-butyl acrylate copolymer), EPDM (ethylene propylene diene monomer), and thermoplastic styrene elastomers. In some embodiments, the above-mentioned non-crosslinking, reactive toughening agents include, but are not limited to, EMA-g-MAH (ethylene-methyl acrylate grafted maleic anhydride copolymer), EMA-g-GMA (ethylene-methyl acrylate grafted glycidyl methacrylate copolymer), EBA-g-MAH (ethylene-butyl acrylate grafted maleic anhydride copolymer), EBA-g-GMA (ethylene-butyl acrylate grafted glycidyl methacrylate copolymer), and thermoplastic styrene elastomers grafted with reactive functional groups.

[0053] The polyamide described in this application contains a large number of polar amide bonds in its molecular chain. The polar groups on the molecular chain can interact through hydrogen bonds, resulting in a highly oriented polyamide along the main chain, exhibiting anisotropic properties. During processing, the polyamide and polyester undergo an ester-amide exchange reaction to produce a block copolymer. Simultaneously, under the action of a processing aid compatibilizer, the block copolymer is uniformly dispersed in the polyethylene matrix, forming a phase-separated structure (i.e., an easily tearable inlay). This allows the cable sheath prepared using the polyethylene composite material to maintain excellent tensile properties in the axial direction (tensile strength of 15-25 MPa). During radial tearing, the defects formed by the phase-separated structure reduce the difficulty of radial tearing, facilitating radial tearing (radial tear strength of 50-200 N). This also reduces the elongation of the cable sheath during tearing, ensuring dimensional stability and enabling radial straight tearing with minimal deformation and a neat tear. The cable sheath prepared using the polyethylene composite material provided in this application has high axial tensile strength and can effectively protect the internal structure of the cable. At the same time, its radially tearable property can provide convenient stripping performance during construction and subsequent maintenance, reducing operational difficulty and cost. That is, the polyethylene composite material provided in the application is suitable for preparing radially tearable cable sheaths.

[0054] In some embodiments, the added amount of the above-mentioned processing aid is 1wt%~5wt% of the above-mentioned polyethylene body.

[0055] In order to meet the requirements of different application environments and facilitate material processing, the polyethylene composite material prepared in this application also includes processing aids to impart various properties to the polyethylene composite material or reduce processing difficulty and improve production efficiency. The above-mentioned processing aids include, but are not limited to, one or more of compatibilizers, antioxidants, anti-ultraviolet agents, masterbatches, thermal stabilizers and antistatic agents. Specifically, the compatibilizer can improve the mixing uniformity of the raw materials so that the above-mentioned easy-to-tear inlay is evenly dispersed in the polyethylene body; the antioxidant can improve the antioxidant properties of the polyethylene composite material during the processing and use process, thereby increasing its service life; the masterbatch can meet the color requirements of cable sheath products for different customers or different application scenarios; the antistatic agent can increase the antistatic properties of the polyethylene composite material, etc.

[0056] It is understood that the present application does not specifically limit the type of the compatibilizer, and any compatibilizer disclosed in the prior art for polyethylene materials is applicable to the present application. In some embodiments, the compatibilizer is a maleic anhydride-based compatibilizer, such as, but not limited to, one or more of maleic anhydride-grafted polyethylene, maleic anhydride-grafted polypropylene, maleic anhydride-grafted POE, and maleic anhydride-grafted SEBS.

[0057] In some embodiments, the antioxidant may be selected from, but not limited to, one or more of antioxidant 1010 , antioxidant 1076 , antioxidant DLTDP, and antioxidant 168 .

[0058] In some embodiments, the anti-UV agent is selected from one or more of a benzoate anti-UV agent and an amine anti-UV agent. Specifically, the benzoate anti-UV agent may be, but is not limited to, one or more of: anti-UV agent RMB, anti-UV agent UV-120, and anti-UV agent UV-2908. The amine anti-UV agent may be, but is not limited to, a hindered amine light stabilizer.

[0059] On the other hand, the present application also provides a method for preparing the above polyethylene composite material, such as Figure 1 As shown, the following steps are included:

[0060] S1. Blending the polyamide, polyester, and toughening agent according to a ratio and granulating the mixture, so that the polyester and the polyamide undergo an ester-amide exchange reaction to obtain an easily tearable inlay;

[0061] S2. Mix the easy-to-tear inlay, the polyethylene main body, and the processing aid according to the ratio, knead the mixture, and then extrude and granulate the mixture, so that the easy-to-tear inlay forms a dispersed phase separation structure in the polyethylene main body, and dry the mixture to obtain a polyethylene composite material.

[0062] The present application does not limit the method of "blending" in step S1, as long as the components can be mixed uniformly, it is within the scope of protection of the present application. In some embodiments, the above blending can be, but is not limited to, stirring and mixing.

[0063] In some embodiments, the blending speed is 100-300 rpm, and the blending time is 5-10 min. Those skilled in the art can adaptably increase / decrease the blending speed, extend or shorten the blending time according to different blending methods, and all of these are within the scope of protection of this application.

[0064] In some embodiments, when preparing the tearable inlay in step S1, the granulation temperature is higher than the melting point of the polyamide, with a temperature difference of 10°C to 20°C, which enables an ester-amide exchange reaction between the polyester and the polyamide. In some embodiments, in step S1, the granulation temperature can be 180°C to 280°C.

[0065] In some embodiments, in step S1, the specific operation of the granulation is: discharging the blended material mass into a twin-screw extruder granulator, and performing the steps of extrusion, strip drawing, pelletizing, and drying to obtain an easily tearable inlay.

[0066] In a specific embodiment of the present application, when the polyamide is nylon 66, during the preparation of the tear-resistant inlay, the granulation process conditions are as follows: screw speed: 300-500 rpm, zone temperatures: 190°C-210°C in zone 1, 210°C-230°C in zone 2, 230°C-250°C in zone 3, 250°C-270°C in zone 4, 250°C-270°C in zone 5, and 230°C-250°C in zone 6, with a die head temperature of 200°C-220°C. It will be appreciated that adaptive adjustment (increasing / decreasing) of the screw speed and adaptive increase / decreasing of the temperatures in each zone, depending on the specific type and amount of the selected polyamide material and the differences in the laboratory extrusion granulator, is within the scope of protection of the present application.

[0067] In some embodiments, in step S2, the mixing and kneading speed is 100-800 rpm, and the mixing and kneading time is 5-20 min. Those skilled in the art may, in actual application, adaptably increase or decrease the mixing and kneading speed, or extend or shorten the mixing and kneading time according to the mixing and kneading method, and all of these are within the scope of protection of this application.

[0068] In some embodiments, when preparing the polyethylene composite material in step S2, the extrusion granulation temperature is controlled within the melting point of the polyamide ±5°C, so that the tearable inlay partially melts and can be dispersed in the polyethylene matrix under the action of the compatibilizer, while forming a uniformly dispersed phase-separated structure. In specific embodiments of the present application, the extrusion granulation temperature can be 150°C to 260°C.

[0069] In a specific embodiment of the present application, when the polyamide is nylon 66, during the preparation of the polyethylene composite material, the extrusion granulation process conditions are as follows: screw speed: 300-500 rpm, the temperatures in each section are: zone 1 180°C-200°C, zone 2 180°C-200°C, zone 3 200°C-220°C, zone 4 220°C-240°C, zone 5 240°C-260°C, zone 6 240°C-260°C, and the die head temperature is 180°C-200°C. It will be understood that adaptive adjustment (increasing / decreasing) of the screw speed and adaptive increase / decreasing of the temperatures in each section, depending on the specific type and amount of polyamide selected in step S1 and the differences in the laboratory extrusion granulator, are all within the scope of protection of the present application.

[0070] In another aspect, the present application also provides the use of the polyethylene composite material in preparing a radially tearable cable sheath. The polyethylene composite material provided herein is suitable for preparing a radially tearable cable sheath. The present application is not limited to the method for preparing the cable sheath. For example, the polyethylene composite material may be placed in an extruder, mixed and melted, and then passed through a mold to form an annular structure that wraps around the cable. The structure is then cooled and solidified to obtain the cable sheath.

[0071] Based on this, the present application also provides a radially tearable cable sheath, which includes the above-mentioned polyethylene composite material.

[0072] In some embodiments, the cable sheath includes but is not limited to an optical cable sheath and an electrical cable sheath.

[0073] On the other hand, the present application also provides an optical cable, which includes the above-mentioned cable sheath.

[0074] It should be understood that materials of the same or similar type, model, quality, properties, or functions as the reagents and instruments used in the following examples can be used to implement this application. The experimental methods used in the following examples are all conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial sources.

[0075] The following are examples and comparative examples:

[0076] Example 1

[0077] The polyethylene composite material provided in this embodiment includes the following components and their weight proportions:

[0078] 12.3 parts of tearable inlay (6 parts of polyamide nylon 66, 6 parts of polybutylene terephthalate PBT, 0.3 parts of toughening agent Lotader AX8900), 150 parts of polyethylene body (90 parts of high-density polyethylene HDPE, number average molecular weight of 98,000, density of 0.951 g / cm³; 60 parts of low-density polyethylene LDPE, number average molecular weight of 11,000, density of 0.917 g / cm³), 6 parts of processing aids (2 parts of maleic anhydride grafted polyethylene, 1 part of antioxidant 1010, 1 part of antioxidant 168, 1 part of UV-120, 1 part of UV-2908).

[0079] The preparation method of the polyethylene composite material comprises the following steps:

[0080] S1. According to the above ratio, the above-mentioned nylon 66, PBT and Lotader AX8900 were mixed, stirred at a speed of 200 rpm for 8 minutes to obtain a first mixed material, and then the first mixed material was vacuum sucked into the extruder hopper for extrusion and granulation. The screw speed was 300 rpm, wherein the temperatures of each section of the machine barrel were: 210°C in zone 1, 230°C in zone 2, 240°C in zone 3, 260°C in zone 4, 270°C in zone 5, 250°C in zone 6, and the head temperature was 220°C to obtain an easy-to-tear inlay.

[0081] S2. According to the above ratio, the above-mentioned easy-to-tear inlay is mixed with HDPE, LDPE, maleic anhydride grafted polyethylene, antioxidant 1010, antioxidant 168, UV-120, and UV-2908, and stirred at a speed of 500 rpm for 10 minutes to obtain a second mixed material, and then the second mixed material is extruded into granules, with a screw speed of 500 rpm, wherein the temperatures of each section of the machine barrel are: 180°C for zone 1, 200°C for zone 2, 220°C for zone 3, 230°C for zone 4, 250°C for zone 5, and 260°C for zone 6, and the head temperature is 190°C. The mixture is pelletized by water-cooling strands and then dried to obtain a polyethylene composite material.

[0082] Example 2

[0083] The polyethylene composite material provided in this embodiment includes the following components and their weight proportions:

[0084] 22.5 parts of easy-tear inlay (12 parts of polyamide nylon 66, 10 parts of polybutylene terephthalate PBT, 0.5 parts of toughening agent Lotader AX8900), 150 parts of polyethylene body (112.5 parts of high-density polyethylene HDPE, number average molecular weight of 60,000, density of 0.942 g / cm³; 37.5 parts of low-density polyethylene LDPE, number average molecular weight of 9,000, density of 0.915 g / cm³), 6 parts of processing aids (1 part of maleic anhydride grafted polyethylene, 1 part of antioxidant 1010, 1 part of antioxidant 168, 1 part of UV-120, 1 part of UV-2908, 1 part of masterbatch).

[0085] The preparation method of the polyethylene composite material comprises the following steps:

[0086] S1. According to the above ratio, the above-mentioned nylon 66, PBT and Lotader AX8900 were mixed, and stirred at a speed of 100 rpm for 10 minutes to obtain a first mixed material. The first mixed material was then vacuum-sucked into the extruder hopper for extrusion and granulation. The screw speed was 400 rpm, wherein the temperatures of each section of the machine barrel were: 210°C in zone 1, 220°C in zone 2, 230°C in zone 3, 250°C in zone 4, 260°C in zone 5, and 260°C in zone 6, and the head temperature was 210°C to obtain an easy-to-tear inlay.

[0087] S2. According to the above ratio, the above-mentioned easy-to-tear inlay is mixed with HDPE, LDPE, maleic anhydride grafted polyethylene, antioxidant 1010, antioxidant 168, UV-120, and UV-2908, and stirred at a speed of 800 rpm for 5 minutes to obtain a second mixed material, and then the second mixed material is extruded into granules, and the screw speed is 400 rpm, wherein the temperatures of each section of the machine barrel are: 180°C in zone 1, 190°C in zone 2, 210°C in zone 3, 230°C in zone 4, 250°C in zone 5, and 260°C in zone 6, and the head temperature is 200°C. The polyethylene composite material is obtained by water-cooled strand cutting and then drying.

[0088] Example 3

[0089] The polyethylene composite material provided in this embodiment includes the following components and their weight proportions:

[0090] 53.5 parts of easy-tear inlay (32 parts of polyamide nylon 66, 20 parts of polybutylene terephthalate PBT, 1.5 parts of toughening agent Lotader AX8900), 150 parts of polyethylene body (120 parts of high-density polyethylene HDPE, number average molecular weight of 50,000, density of 0.940 g / cm³; 30 parts of low-density polyethylene LDPE, number average molecular weight of 5,000, density of 0.912 g / cm³), 6 parts of processing aids (2 parts of maleic anhydride grafted polyethylene, 1 part of antioxidant 1010, 1 part of antioxidant 168, 1 part of UV-120, 1 part of UV-2908).

[0091] The preparation method of the polyethylene composite material comprises the following steps:

[0092] S1. According to the above ratio, the above-mentioned nylon 66, PBT and Lotader AX8900 were mixed, stirred at a speed of 300 rpm for 5 minutes to obtain a first mixed material, and then the first mixed material was vacuum sucked into the extruder hopper for extrusion and granulation. The screw speed was 500 rpm, wherein the temperatures of each section of the barrel were: 190°C in zone 1, 210°C in zone 2, 230°C in zone 3, 250°C in zone 4, 270°C in zone 5, and 250°C in zone 6, and the head temperature was 210°C to obtain an easy-to-tear inlay.

[0093] S2. According to the above ratio, the above-mentioned easy-to-tear inlay is mixed with HDPE, LDPE, maleic anhydride grafted polyethylene, antioxidant 1010, antioxidant 168, UV-120, and UV-2908, and stirred at a speed of 100 rpm for 20 minutes to obtain a second mixed material, and then the second mixed material is extruded into granules, and the screw speed is 300 rpm, wherein the temperatures of each section of the machine barrel are: 200°C for zone 1, 200°C for zone 2, 220°C for zone 3, 240°C for zone 4, 260°C for zone 5, and 260°C for zone 6, and the head temperature is 200°C. The polyethylene composite material is obtained by water-cooled strand cutting and then drying.

[0094] Example 4

[0095] The polyethylene composite material provided in this embodiment includes the following components and their weight proportions:

[0096] 30.5 parts of tearable inlay (15 parts of polyamide nylon 66, 15 parts of polybutylene terephthalate PBT, 0.5 parts of toughening agent Lotader AX8900), 110 parts of polyethylene body (90 parts of high-density polyethylene HDPE, the same as in Example 1; 20 parts of low-density polyethylene LDPE, the same as in Example 1), 4 parts of processing aids (1 part of maleic anhydride grafted polyethylene, 1 part of antioxidant 1010, 1 part of antioxidant 168, 1 part of UV-120).

[0097] Example 5

[0098] The polyethylene composite material provided in this embodiment includes the following components and their weight proportions:

[0099] 60 parts of easy-tear inlay (28 parts of polyamide nylon 66, 31.5 parts of polybutylene terephthalate PBT, 1.5 parts of toughening agent Lotader AX8900), 150 parts of polyethylene body (125 parts of high-density polyethylene HDPE, the same as in Example 1; 25 parts of low-density polyethylene LDPE, the same as in Example 1), 6 parts of processing aids (2 parts of maleic anhydride grafted polyethylene, 1 part of antioxidant 1010, 1 part of antioxidant 168, 1 part of UV-120, and 1 part of UV-2908).

[0100] Example 6

[0101] The polyethylene composite material provided in this embodiment includes the following components and their weight proportions:

[0102] 18 parts of easy-tear inlay (7 parts of polyamide nylon 66, 10.5 parts of polybutylene terephthalate PBT, 0.5 parts of toughening agent Lotader AX8900), 180 parts of polyethylene main body (120 parts of high-density polyethylene HDPE, the same as in Example 1; 60 parts of low-density polyethylene LDPE, the same as in Example 1), 7 parts of processing aids (3 parts of maleic anhydride grafted polyethylene, 1 part of antioxidant 1010, 1 part of antioxidant 168, 1 part of UV-120, 1 part of masterbatch).

[0103] Example 7

[0104] The polyethylene composite material provided in this embodiment includes the following components and their weight proportions:

[0105] 12.3 parts of tearable inlay (6 parts of polyamide nylon MXD-6, 6 parts of polybutylene terephthalate PET, 0.3 parts of toughening agent Lotader AX8900), 130 parts of polyethylene main body (90 parts of high-density polyethylene HDPE, the same as in Example 1; 40 parts of low-density polyethylene LDPE, the same as in Example 1), 5 parts of processing aids (1 part of maleic anhydride grafted POE, 1 part of antioxidant 1010, 1 part of antioxidant 168, 1 part of UV-120, and 1 part of UV-2908).

[0106] The preparation method of the polyethylene composite material comprises the following steps:

[0107] S1. According to the above ratio, the above-mentioned nylon MXD-6, PET and toluenesulfonic acid were mixed, stirred at a speed of 300 rpm for 5 minutes to obtain a first mixed material, and then the first mixed material was vacuum sucked into the extruder hopper for extrusion and granulation. The screw speed was 500 rpm, wherein the temperatures of each section of the machine barrel were: 180°C in zone 1, 190°C in zone 2, 220°C in zone 3, 240°C in zone 4, 250°C in zone 5, 230°C in zone 6, and the head temperature was 200°C to obtain an easy-to-tear inlay.

[0108] S2. According to the above ratio, the above-mentioned easy-to-tear inlay and HDPE, LDPE, maleic anhydride grafted POE, antioxidant 1010, antioxidant 168, UV-120, and UV-2908 are mixed, and the mixture is stirred at a speed of 100 rpm for 20 minutes to obtain a second mixed material, and then the second mixed material is extruded into granules, and the screw speed is 300 rpm, wherein the temperatures of each section of the machine barrel are: 180°C for zone 1, 200°C for zone 2, 220°C for zone 3, 220°C for zone 4, 240°C for zone 5, and 240°C for zone 6, and the head temperature is 180°C. The mixture is pelletized by water-cooling strands and then dried to obtain a polyethylene composite material.

[0109] Example 8

[0110] The polyethylene composite material provided in this embodiment includes the following components and their weight proportions:

[0111] 15.5 parts of tearable inlay (8.5 parts of polyamide nylon 1010, 6.7 parts of polybutylene terephthalate PTT, 0.3 parts of toughening agent Lotader AX8900), 150 parts of polyethylene body (90 parts of high-density polyethylene HDPE, the same as in Example 1; 60 parts of low-density polyethylene LDPE, the same as in Example 1), and 6 parts of processing aids (2 parts of maleic anhydride grafted polypropylene, 1 part of antioxidant 1076, 1 part of antioxidant 168, 1 part of UV-120, and 1 part of UV-2908).

[0112] The preparation method of the polyethylene composite material comprises the following steps:

[0113] S1. According to the above ratio, the above-mentioned nylon 1010, PTT and Lotader AX8900 were mixed, stirred at a speed of 300 rpm for 5 minutes to obtain a first mixed material, and then the first mixed material was vacuum sucked into the extruder hopper for extrusion and granulation. The screw speed was 500 rpm, wherein the temperatures of each section of the machine barrel were: 180°C in zone 1, 180°C in zone 2, 190°C in zone 3, 200°C in zone 4, 210°C in zone 5, and 200°C in zone 6, and the head temperature was 180°C to obtain an easy-to-tear inlay.

[0114] S2. According to the above ratio, the above-mentioned easy-to-tear inlay is mixed with HDPE, LDPE, maleic anhydride grafted polypropylene, antioxidant 1076, antioxidant 168, UV-120, and UV-2908, and stirred at a speed of 100 rpm for 20 minutes to obtain a second mixed material, and then the second mixed material is extruded into granules, and the screw speed is 300 rpm, wherein the temperatures of each section of the machine barrel are: 170°C in zone 1, 180°C in zone 2, 180°C in zone 3, 200°C in zone 4, 210°C in zone 5, and 190°C in zone 6, and the head temperature is 170°C. The polyethylene composite material is obtained by water-cooled strand cutting and then drying.

[0115] Example 9

[0116] The polyethylene composite material provided in this embodiment includes the following components and their weight proportions:

[0117] 27.8 parts of tearable inlay (12 parts of polyamide nylon 11, 15 parts of polybutylene terephthalate PBT, 0.8 parts of toughening agent Lotader AX8900), 160 parts of polyethylene main body (110 parts of high-density polyethylene HDPE, the same as in Example 2; 50 parts of low-density polyethylene LDPE, the same as in Example 2), 6 parts of processing aids (2 parts of maleic anhydride grafted SEBS, 1 part of antioxidant 1010, 1 part of antioxidant DLTDP, 1 part of UV-120, and 1 part of UV-2908).

[0118] The preparation method of the above-mentioned polyethylene composite material comprises the following steps:

[0119] S1. According to the above ratio, the above-mentioned nylon 11, PBT and Lotader AX8900 were mixed, stirred at a speed of 300 rpm for 5 minutes to obtain a first mixed material, and then the first mixed material was vacuum sucked into the extruder hopper for extrusion and granulation. The screw speed was 500 rpm, wherein the temperatures of each section of the machine barrel were: 170°C in zone 1, 180°C in zone 2, 180°C in zone 3, 190°C in zone 4, 200°C in zone 5, and 190°C in zone 6, and the head temperature was 170°C to obtain an easy-to-tear inlay.

[0120] S2. According to the above ratio, the above-mentioned easy-to-tear inlay and HDPE, LDPE, maleic anhydride grafted SEBS, antioxidant 1010, antioxidant DLTDP, UV-120, and UV-2908 are mixed, and stirred at a speed of 100 rpm for 20 minutes to obtain a second mixed material, and then the second mixed material is extruded into granules, and the screw speed is 300 rpm, wherein the temperatures of each section of the machine barrel are: 170°C for zone 1, 170°C for zone 2, 180°C for zone 3, 180°C for zone 4, 190°C for zone 5, and 190°C for zone 6, and the head temperature is 160°C. The polyethylene composite material is obtained by water-cooled strand cutting and then drying.

[0121] Example 10

[0122] The polyethylene composite material provided in this embodiment includes the following components and their weight proportions:

[0123] 25.5 parts of tearable inlay (13 parts of polyamide nylon 1212, 12 parts of polybutylene terephthalate PBT, 0.5 parts of toughening agent Lotader AX8900), 120 parts of polyethylene body (90 parts of high-density polyethylene HDPE, the same as in Example 3; 30 parts of low-density polyethylene LDPE, the same as in Example 3), 5 parts of processing aids (1 part of maleic anhydride grafted polypropylene, 1 part of antioxidant 1010, 1 part of antioxidant 168, 1 part of UV-120, 1 part of UV-2908).

[0124] The preparation method of the above-mentioned polyethylene composite material comprises the following steps:

[0125] S1. According to the above ratio, the above-mentioned nylon 1212, PBT and Lotader AX8900 were mixed, stirred at a speed of 300 rpm for 5 minutes to obtain a first mixed material, and then the first mixed material was vacuum sucked into the extruder hopper for extrusion and granulation. The screw speed was 400 rpm, wherein the temperatures of each section of the machine barrel were: 170°C in zone 1, 180°C in zone 2, 180°C in zone 3, 190°C in zone 4, 200°C in zone 5, 170°C in zone 6, and the head temperature was 160°C to obtain an easy-to-tear inlay.

[0126] S2. According to the above ratio, the above-mentioned easy-to-tear inlay and HDPE, LDPE, maleic anhydride grafted POE, antioxidant 1010, antioxidant 168, UV-120, and UV-2908 are mixed, and the mixture is stirred at a speed of 100 rpm for 20 min to obtain a second mixed material, and then the second mixed material is extruded into granules, and the screw speed is 300 rpm, wherein the temperatures of each section of the machine barrel are: 160°C in zone 1, 160°C in zone 2, 170°C in zone 3, 170°C in zone 4, 180°C in zone 5, and 180°C in zone 6, and the head temperature is 150°C. The mixture is pelletized by water-cooling strands and then dried to obtain a polyethylene composite material.

[0127] Comparative Example 1

[0128] The polyethylene composite material provided in this comparative example does not include an easily tearable inlay, and is otherwise the same as in Example 1.

[0129] The preparation method of the polyethylene composite material provided in this comparative example is the same as that in Example 1.

[0130] Comparative Example 2

[0131] The polyethylene composite material provided in this comparative example includes 6 parts of easy-tear inlays (2.9 parts of polyamide nylon 66, 2.9 parts of polybutylene terephthalate PBT, and 0.2 parts of toughening agent Lotader AX890), and the rest is the same as in Example 1.

[0132] The preparation method of the polyethylene composite material provided in this comparative example is the same as that in Example 1.

[0133] Comparative Example 3

[0134] The polyethylene composite material provided in this comparative example includes 70 parts of easy-tear inlays (34 parts of nylon 66, 34 parts of polybutylene terephthalate PBT, and 2 parts of toughening agent Lotader AX8900), and the rest is the same as in Example 1.

[0135] The preparation method of the polyethylene composite material provided in this comparative example is the same as that in Example 1.

[0136] Comparative Example 4

[0137] The polyethylene composite material provided in this comparative example includes 150 parts of polyethylene main body (130 parts of high-density polyethylene and 20 parts of low-density polyethylene), and the rest is the same as in Example 1.

[0138] The preparation method of the polyethylene composite material provided in this comparative example is the same as that in Example 1.

[0139] Comparative Example 5

[0140] The polyethylene composite material provided in this comparative example includes 150 parts of polyethylene main body (75 parts of high-density polyethylene and 75 parts of low-density polyethylene, and the rest is the same as in Example 1.

[0141] The preparation method of the polyethylene composite material provided in this comparative example is the same as that in Example 1.

[0142] The polyethylene composite materials prepared in Examples 1 to 10 and Comparative Examples 1 to 5 were mixed and melted, and then formed into a ring structure for wrapping the cable through a semi-extrusion die. The structure was then cooled and solidified to obtain cable sheath samples. The performance of the cable sheath samples was tested as follows:

[0143] 1) Radial tearing performance

[0144] The trouser-type tearing method is used to test the radial tearing performance of the sample. Specifically, a sample with a length of 15 cm, a width of 5 cm, and a thickness of 2 mm is cut in the radial direction, and a slit is cut in the radial direction to half of the length to form two parts similar to trouser legs. The samples are then clamped on the upper and lower clamps of the tensile testing machine respectively. The center of the connecting line between the main axis of the sample and the clamp coincides to ensure that the sample is evenly stressed during the test. The test speed is set to 100 mm / min, and a tensile force is applied to the sample to expand the crack in the radial direction. The radial maximum tearing force is used to represent the radial tearing strength of the sample. The radial tearing curve of the sample and the fracture morphology of the sample after tearing are observed to comprehensively evaluate the radial tearing performance of the sample.

[0145] Figure 2 、 Figure 3 The radial tearing effect diagrams of the cable sheath samples prepared by using the polyethylene composite materials provided by Example 1 and Comparative Example 1 are respectively.

[0146] 2) Axial tensile properties

[0147] Refer to GB / T 1040 to test the axial tensile strength of the specimen.

[0148] The test results are shown in Table 1.

[0149] Table 1 Properties of cable sheath samples prepared in Examples 1 to 10 and Comparative Examples 1 to 5

[0150]

[0151] Test results show that by introducing a tearable inlay capable of forming a phase-separated structure into the polyethylene main body, and regulating the ratio of polyamide, polyester, and toughening agent in the tearable inlay, as well as the ratio of the tearable inlay to the polyethylene main body, the prepared cable sheath has excellent axial tensile properties (tensile strength of 15-25 MPa), good radial tearing properties (i.e., radial tear strength of 50-200 N), high dimensional stability, and the ability to tear radially with minimal deformation at the tear site and a neat tear. In practical applications, cable sheaths prepared using the polyethylene composite material provided by this application can effectively protect the internal structure of the cable while providing convenient stripping performance, reducing operational difficulty and cost, and facilitating the installation, construction, and maintenance of the cable sheath.

[0152] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A polyethylene composite material for preparing a radially tearable cable sheath, characterized in that: It is made by mixing polyethylene main body, easy-tear inlay and processing aids and then extruding and granulating. The weight ratio of the easy-to-tear inlay to the polyethylene main body is (0.05-0.4):1; The easy-tear inlay is prepared by granulating a mixture of polyamide, polyester and a toughening agent to allow the polyamide and polyester to undergo an ester-amide exchange reaction, wherein the weight ratio of the polyamide to the polyester is 1:(0.5-2); The number average molecular weight of the polyethylene main body is 9000~100000, and the polyethylene main body is composed of high-density polyethylene and low-density polyethylene, wherein the weight ratio of high-density polyethylene to low-density polyethylene is (1.5~5):

1.

2. The polyethylene composite material according to claim 1, characterized in that The amount of the toughening agent added is 1 wt% to 3 wt% of the total weight of the polyamide and the polyester.

3. The polyethylene composite material according to claim 1, characterized in that The melting point of the polyamide is 170° C. to 270° C.; and / or, The polyester is selected from one or more of polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate; and / or, The toughening agent is a non-crosslinking toughening agent, including a non-crosslinking non-reactive toughening agent and / or a non-crosslinking reactive toughening agent.

4. The polyethylene composite material according to claim 3, characterized in that The polyamide is selected from one or more of nylon 6, nylon 66, nylon MXD-6, nylon 1010, nylon 11, nylon 12 and nylon 1212.

5. The polyethylene composite material according to claim 1, characterized in that The processing aids include one or more of a compatibilizer, an antioxidant, an anti-ultraviolet agent, a masterbatch, a heat stabilizer and an antistatic agent; and / or, The added amount of the processing aid is 1 wt% to 5 wt% of the polyethylene main body.

6. The method for preparing the polyethylene composite material according to any one of claims 1 to 5, comprising the steps of: S1. Blending the polyamide, polyester, and toughening agent according to a ratio and granulating the mixture, so that the polyester and the polyamide undergo an ester-amide exchange reaction to obtain an easily tearable inlay; S2. Mixing the tearable inlay, the polyethylene main body, and the processing aid according to a ratio, kneading the mixture, and then extruding and granulating the mixture so that the tearable inlay forms a dispersed phase separation structure in the polyethylene main body, and drying the mixture to obtain a polyethylene composite material.

7. The preparation method according to claim 6, characterized in that In step S1, the blending speed is 100-300 rpm, the blending time is 5-10 min, the granulation temperature is higher than the melting point of the polyamide, and the temperature difference is 10° C.-20° C.; and / or, In step S2, the rotation speed of the mixing and kneading is 100-800 rpm, the mixing and kneading time is 5-20 min, and the temperature of the extrusion granulation is within the range of the melting point of the polyamide ±5°C.

8. A radially tearable cable sheath, characterized in that: It comprises the polyethylene composite material according to any one of claims 1 to 5.

9. An optical cable, characterized in that: It comprises the cable sheath as claimed in claim 8.

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