Polyamide cable material as well as preparation method and application thereof

Abstract

The invention discloses a polyamide cable material as well as a preparation method and application thereof. The cable material is prepared from the following raw materials in parts by weight: 100 parts of polyamide, 10 to 40 parts of nano magnesium hydroxide whisker, 1 to 5 parts of silane coupling agent, 1 to 5 parts of amphiphilic block copolymer, 1 to 10 parts of pentaerythritol triacrylate and 1 to 5 parts of antioxidant, wherein the fiber length of the nano magnesium hydroxide whisker is 200 to 1000 nm, and the fiber diameter of the nano magnesium hydroxide whisker is 30 to 80 nm. The polyamide cable material has good temperature resistance (can tolerate the high temperature of 135 DEG C for a long time), flame retardance (the limit oxygen index can reach 31% or above, preferably 33.5%), mechanical properties (excellent tensile strength and low-temperature impact resistance) and relatively high volume resistivity.

Description

Technical Field

[0001] This invention relates to the field of cable material technology. More specifically, it relates to a polyamide cable material, its preparation method, and its applications. Background Technology

[0002] Cables are the primary means of transmitting electricity and information. A cable consists of inner conductors and an outer sheath; each set of conductors is insulated from the others, and the entire cable is covered by a highly insulating sheath. Many cables are installed outdoors, exposed to wind and sun for extended periods, making them highly susceptible to aging and damage, severely impacting their lifespan and safety.

[0003] Polyamide is a common component of cable materials, possessing advantages such as good abrasion resistance. However, existing conventional polyamide cable materials can only withstand temperatures below 110℃, and their flame-retardant properties do not meet national standards. Improving the temperature resistance and flame-retardant properties of polyamide cable materials is a key research focus in this field. Summary of the Invention

[0004] Based on the above problems, the purpose of this invention is to provide a polyamide cable material, its preparation method, and its application. The polyamide cable material possesses good temperature resistance (able to withstand high temperatures of 135°C for extended periods), flame retardancy (limiting oxygen index can reach over 31%, preferably 33.5%), mechanical properties (excellent tensile strength and low-temperature impact resistance), and high volume resistivity.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a polyamide cable material, wherein, by weight, the raw materials forming the cable material comprise: 100 parts polyamide, 10-40 parts of nano magnesium hydroxide whiskers, 1-5 parts silane coupling agent, 1-5 parts amphiphilic block copolymer, 1-10 parts pentaerythritol triacrylate, and, 1-5 parts antioxidant; The nano-magnesium hydroxide whiskers have a fiber length of 200-100 nm and a fiber diameter of 30-80 nm.

[0006] In existing technologies, magnesium hydroxide is typically used as a flame retardant in granular form, resulting in poor flame retardant performance and poor compatibility with the matrix resin, leading to uneven dispersion within the matrix. In this invention, the polyamide cable material incorporates nanofiber-like magnesium hydroxide as a flame retardant within the polyamide. A silane coupling agent is grafted onto the surface of the nanofiber magnesium hydroxide whiskers, and an amphiphilic block copolymer is used for self-assembly on the surface of the surface-modified nanofiber magnesium hydroxide whiskers. This results in nanofiber magnesium hydroxide whiskers with an amphiphilic block copolymer on their surface, ensuring uniform dispersion and a tighter bond between the nanofiber magnesium hydroxide whiskers and the polyamide, thus improving the temperature resistance and flame retardancy of the polyamide cable material. The polyamide cable material of this invention is halogen-free and exhibits excellent temperature resistance and flame retardancy.

[0007] Furthermore, in the cable material, the silane coupling agent is grafted onto the surface of the nano-magnesium hydroxide whiskers, and the oleophilic end of the amphiphilic block copolymer is assembled on the surface of the nano-magnesium hydroxide whiskers by the silane coupling agent, while the hydrophilic end is connected to the polyamide.

[0008] Furthermore, the polyamide is selected from polyamide 1010. Polyamide 1010 is a radiation-crosslinkable polyamide material, which can be obtained by the condensation polymerization of a salt formed by sebacic acid and sebacic diamine; polyamide 1010 has high mechanical strength, good wear resistance and self-lubricating properties, and is suitable for use as the main material of polyamide cable material.

[0009] Furthermore, the silane coupling agent is an amino-functionalized silane coupling agent.

[0010] Furthermore, the silane coupling agent is selected from KH550.

[0011] Furthermore, the amphiphilic block copolymer is selected from polystyrene-b-polyacrylic acid.

[0012] In the technical solution of this invention, the nano-magnesium hydroxide whiskers can be commercially available or prepared by methods in the prior art.

[0013] Furthermore, the antioxidant is selected from one or more of 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and tris[2,4-di-tert-butylphenyl]phosphite.

[0014] Furthermore, the antioxidant is a mixture of 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and tris[2,4-di-tert-butylphenyl]phosphite in a mass ratio of 2:1. The combined use of these two agents achieves a synergistic antioxidant effect, resulting in long-term, excellent antioxidant performance.

[0015] In the technical solution of this invention, pentaerythritol triacrylate is a crosslinking aid component, which initiates the crosslinking of polyamide 1010 under the action of irradiation.

[0016] Furthermore, the molecular weight of the polystyrene-b-polyacrylic acid is 15000-b-1600 g / mol.

[0017] Furthermore, the raw material also contains 0-3 parts of halogen-free color masterbatch.

[0018] Furthermore, the raw materials forming the cable material, by weight, include: 100 parts polyamide, 30 parts of nano magnesium hydroxide whiskers, 2 parts silane coupling agent, 4 parts of amphiphilic block copolymers, 5 parts pentaerythritol triacrylate, and, 3 portions of antioxidants.

[0019] In the polyamide cable material provided by this invention, nano-magnesium hydroxide whiskers are more uniformly dispersed in the polyamide through the action of silane coupling agents, such as KH550, and amphiphilic block polymers, such as styrene-b-polyacrylic acid, and the bond with the polyamide is tighter. Grafting silane coupling agents onto the surface of the nano-magnesium hydroxide whiskers reduces the surface energy of the fibers, changing the surface from hydrophilic to hydrophobic, making the nano-magnesium hydroxide whiskers more compatible with polyamide and other components. Furthermore, the bridging effect of the nanofibers improves the toughness and temperature resistance of the polyamide cable material. In the polyamide cable material provided by this invention, the silane coupling agent grafted onto the surface of the nano-magnesium hydroxide whiskers, such as KH550, has amino groups, which can combine with other polar components in the polyamide cable material, especially with amide groups, resulting in a tighter bond and improved cable material strength. The amino groups in KH550 also contribute to flame retardancy. This invention uses an amphiphilic block copolymer, such as polystyrene-b-polyacrylic acid, to self-assemble on the surface of surface-modified nano-magnesium hydroxide whiskers, resulting in nano-magnesium hydroxide whiskers with an amphiphilic block copolymer assembled on the surface. One end of the self-assembled amphiphilic block copolymer polystyrene-b-polyacrylic acid is connected to the nano-magnesium hydroxide whisker, and the other end is connected to polyamide. Specifically, the oleophilic end of polystyrene-b-polyacrylic acid first self-assembles on the surface of the surface-modified nano-magnesium hydroxide whiskers, and then the hydrophilic end of polystyrene-b-polyacrylic acid is connected to polyamide, making the connection between the nano-magnesium hydroxide whiskers and polyamide tighter and improving the thermal stability of polyamide cable material.

[0020] In a second aspect, the present invention provides a method for preparing the polyamide cable material as described in the first aspect above, the method comprising the following steps: Under stirring, a silane coupling agent was added to the nano magnesium hydroxide whiskers, and the surface was modified by stirring for 1-3 hours to obtain nano magnesium hydroxide whiskers with silane coupling agent grafted on the surface. Add the amphiphilic block copolymer and continue stirring for 1-3 hours to obtain nano-magnesium hydroxide whiskers with the amphiphilic block copolymer assembled on the surface; The nano-magnesium hydroxide whiskers with amphiphilic block copolymers assembled on their surfaces, along with polyamide, pentaerythritol triacrylate, and antioxidants, are mixed evenly and then extruded and granulated to obtain the polyamide cable material.

[0021] Furthermore, the extrusion granulation is carried out in a twin-screw extruder, and the extrusion temperature is 210-240℃.

[0022] Thirdly, the present invention provides the application of the polyamide cable material as described in the first aspect above in the preparation of cables.

[0023] Unless otherwise specified, the preparation methods in this invention are all conventional methods; and the raw materials used can be obtained from publicly available commercial sources unless otherwise specified.

[0024] The beneficial effects of this invention are as follows: This invention addresses the technical problems of poor temperature resistance and flame retardancy in polyamide cable materials by introducing nanofiber-like magnesium hydroxide as a flame retardant into polyamide. The invention grafts a silane coupling agent (preferably an amino-functionalized silane coupling agent) onto the surface of the nano-magnesium hydroxide whiskers and uses an amphiphilic block polymer (preferably polystyrene-b-polyacrylic acid) for self-assembly on the surface-modified nano-magnesium hydroxide whiskers. This results in more uniform dispersion and a tighter bond between the nano-magnesium hydroxide whiskers and the polyamide. The polyamide cable material of this invention can effectively improve the temperature resistance and flame retardancy of polyamide cable materials without the need for additional flame retardants. The polyamide cable material of this invention can withstand temperatures up to 135°C, is halogen-free, and exhibits excellent temperature resistance and flame retardant properties. Detailed Implementation

[0025] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0026] Example 1 A method for preparing polyamide cable material includes the following steps: 1) Prepare materials according to the weight proportions: 100 parts of polyamide 1010, 30 parts of nano magnesium hydroxide whiskers (fiber length 200-1000nm, fiber diameter 30-80nm). Two portions of KH550, 4 parts polystyrene-b-polyacrylic acid, 5 parts pentaerythritol triacrylate, 2 parts of antioxidant 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1 part antioxidant tris[2,4-di-tert-butylphenyl] phosphite; 2) Under stirring, KH550 was added to the nano magnesium hydroxide whiskers and stirred for 2 hours to modify the surface, resulting in nano magnesium hydroxide whiskers with KH550 grafted on the surface. Then, polystyrene-b-polyacrylic acid was added and stirred for another 2 hours to obtain nano magnesium hydroxide whiskers with amphiphilic block copolymers assembled on the surface. 3) The nano magnesium hydroxide whiskers with amphiphilic block copolymers on the surface obtained in step 2) are mixed evenly with polyamide, pentaerythritol triacrylate and antioxidant, and then extruded and granulated using a twin-screw extruder at an extrusion temperature of 210-240℃ to obtain the polyamide cable material.

[0027] Example 2 A method for preparing polyamide cable material includes the following steps: 1) Prepare materials according to the weight proportions: 100 parts of polyamide 1010, 35 parts of nano-magnesium hydroxide whiskers (fiber length 200-1000nm, fiber diameter 30-80nm). 3 KH550, 5 parts polystyrene-b-polyacrylic acid, 5 parts pentaerythritol triacrylate, Two parts of antioxidant 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; 2) Under stirring, KH550 was added to the nano magnesium hydroxide whiskers and stirred for 2 hours to modify the surface, resulting in nano magnesium hydroxide whiskers with KH550 grafted on the surface. Then, the amphiphilic block copolymer polystyrene-b-polyacrylic acid was added and stirred for another 2 hours to obtain nano magnesium hydroxide whiskers with the amphiphilic block copolymer assembled on the surface. 3) The nano magnesium hydroxide whiskers with amphiphilic block copolymers on the surface obtained in step 2) are mixed evenly with polyamide, pentaerythritol triacrylate and antioxidant, and then extruded and granulated using a twin-screw extruder at an extrusion temperature of 210-240℃ to obtain the polyamide cable material.

[0028] Example 3 A method for preparing polyamide cable material includes the following steps: 1) Prepare materials according to the weight proportions: 100 parts of polyamide 1010, 15 parts of nano-magnesium hydroxide whiskers (fiber length 200-1000nm, fiber diameter 30-80nm). 2 KH550, 2 parts polystyrene-b-polyacrylic acid, 5 parts pentaerythritol triacrylate, 1 part of tris[2,4-di-tert-butylphenyl] phosphite; 2) Under stirring, amino-functionalized silane KH550 was added to the nano magnesium hydroxide whiskers and stirred for 2 hours to modify the surface, resulting in nano magnesium hydroxide whiskers with KH550 grafted on the surface. Then, amphiphilic block copolymer polystyrene-b-polyacrylic acid was added and stirred for another 2 hours to obtain nano magnesium hydroxide whiskers with amphiphilic block copolymer assembled on the surface. 3) The nano magnesium hydroxide whiskers with amphiphilic block copolymers on the surface obtained in step 2) are mixed evenly with polyamide, pentaerythritol triacrylate and antioxidant, and then extruded and granulated using a twin-screw extruder at an extrusion temperature of 210-240℃ to obtain the polyamide cable material.

[0029] Example 4 A method for preparing polyamide cable material includes the following steps: 1) Prepare materials according to the weight proportions: 100 parts of polyamide 1010, 25 parts of nano magnesium hydroxide whiskers (fiber length 200-1000nm, fiber diameter 30-80nm). 2 KH550, 3 parts polystyrene-b-polyacrylic acid, 5 parts pentaerythritol triacrylate, 2 parts of antioxidant 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1 part antioxidant tris[2,4-di-tert-butylphenyl] phosphite; 2) Under stirring, KH550 was added to the nano magnesium hydroxide whiskers and stirred for 2 hours to modify the surface, resulting in nano magnesium hydroxide whiskers with KH550 grafted on the surface. Then, the amphiphilic block copolymer polystyrene-b-polyacrylic acid was added and stirred for another 2 hours to obtain nano magnesium hydroxide whiskers with the amphiphilic block copolymer assembled on the surface. 3) The nano magnesium hydroxide whiskers with amphiphilic block copolymers on the surface obtained in step 2) are mixed evenly with polyamide, pentaerythritol triacrylate and antioxidant, and then extruded and granulated using a twin-screw extruder at an extrusion temperature of 210-240℃ to obtain the polyamide cable material.

[0030] Example 5 A method for preparing polyamide cable material includes the following steps: 1) Prepare materials according to the weight proportions: 100 parts of polyamide 1010, 25 parts of nano magnesium hydroxide whiskers (fiber length 200-1000nm, fiber diameter 30-80nm). 2 KH550, 4 parts polystyrene-b-polyacrylic acid, 5 parts pentaerythritol triacrylate, Two parts of antioxidant 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1 part antioxidant tris[2,4-di-tert-butylphenyl]phosphite, and 1 part yellow masterbatch, 2) Under stirring, KH550 was added to the nano magnesium hydroxide whiskers and stirred for 2 hours to modify the surface, resulting in nano magnesium hydroxide whiskers with KH550 grafted on the surface. Then, the amphiphilic block copolymer polystyrene-b-polyacrylic acid was added and stirred for another 2 hours to obtain nano magnesium hydroxide whiskers with the amphiphilic block copolymer assembled on the surface. 3) The nano magnesium hydroxide whiskers with amphiphilic block copolymers on the surface obtained in step 2) are mixed evenly with polyamide, pentaerythritol triacrylate and antioxidant, and then extruded and granulated using a twin-screw extruder at an extrusion temperature of 210-240℃ to obtain the polyamide cable material.

[0031] Comparative Example 1 A method for preparing polyamide cable material includes the following steps: 1) Prepare materials according to the weight proportions: 100 parts of polyamide 1010, 30 portions of magnesium hydroxide powder particles (average size: 1-20 μm, irregular shape). 5 parts pentaerythritol triacrylate, 2 parts of antioxidant 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1 part antioxidant tris[2,4-di-tert-butylphenyl] phosphite; 2) Mix all components evenly, and extrude and granulate using a twin-screw extruder at an extrusion temperature of 210-240℃ to obtain the polyamide cable material.

[0032] Comparative Example 2 A method for preparing polyamide cable material includes the following steps: 1) Prepare materials according to the weight proportions: 100 parts of polyamide 1010, 30 parts of nano magnesium hydroxide whiskers (fiber length 200-1000nm, fiber diameter 30-80nm). Two portions of KH550, 5 parts pentaerythritol triacrylate, 2 parts of antioxidant 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1 part antioxidant tris[2,4-di-tert-butylphenyl] phosphite; 2) Under stirring, KH550 was added to the nano magnesium hydroxide whiskers and stirred continuously for 2 hours to modify the surface and obtain nano magnesium hydroxide whiskers with KH550 grafted on the surface. 3) Mix the KH550 modified nano magnesium hydroxide whiskers obtained in step 2) with polyamide, pentaerythritol triacrylate and antioxidant evenly, and granulate by extrusion using a twin-screw extruder at an extrusion temperature of 210-240℃ to obtain the polyamide cable material.

[0033] Comparative Example 3 A method for preparing polyamide cable material includes the following steps: 1) Prepare materials according to the weight proportions: 100 parts of polyamide 1010, 30 portions of magnesium hydroxide powder particles (average size: 1-20 μm, irregular shape). Two portions of KH550, 4 parts polystyrene-b-polyacrylic acid, 5 parts pentaerythritol triacrylate, 2 parts of antioxidant 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1 part antioxidant tris[2,4-di-tert-butylphenyl] phosphite; 2) Under stirring, KH550 was added to the magnesium hydroxide powder particles and stirred for 2 hours to modify the surface, resulting in magnesium hydroxide powder particles with KH550 grafted on the surface. Then, polystyrene-b-polyacrylic acid was added and stirred for another 2 hours to obtain magnesium hydroxide powder particles with amphiphilic block copolymers assembled on the surface. 3) The magnesium hydroxide powder particles with amphiphilic block copolymers on the surface obtained in step 2) are mixed evenly with polyamide, pentaerythritol triacrylate and antioxidant, and then extruded and granulated using a twin-screw extruder at an extrusion temperature of 210-240℃ to obtain the polyamide cable material.

[0034] The polyamide cable materials prepared in the above embodiments and comparative examples were subjected to heat resistance and flame retardancy tests. The results are shown in Table 1 below.

[0035] The testing methods and reference standards are as follows: The stabilization time (h) at 135℃ is in accordance with GB / T 7141-2008 (Test Method for Thermal Aging of Plastics). The limiting oxygen index is based on GB / T 2406.2-2021 (Determination of combustion behavior of plastics by oxygen index method). Tensile strength is measured according to GB / T 1040.1-2018 (Determination of tensile properties of plastics). -40℃ Low Temperature Impact Embrittlement: The sample was kept at -40℃ for 2 hours, and then immediately subjected to GB / T 1043.1-2018 (Determination of Impact Properties of Plastic Simply Supported Beams). The volume resistivity at 20℃ is in accordance with GB / T 31838.2-2019 (Test methods for resistivity and conductivity of solid insulating materials).

[0036] Table 1

[0037] It is evident that in each embodiment, amino-functionalized silane KH550 was grafted onto the surface of the nano-magnesium hydroxide whiskers, and the amphiphilic block polymer polystyrene-b-polyacrylic acid was used for self-assembly on the surface-modified nano-magnesium hydroxide whiskers, resulting in more uniform dispersion of the nano-magnesium hydroxide whiskers in the polyamide and a tighter bond between them. Test results show that the polyamide cable material of this invention exhibits higher thermal stability and flame retardancy, can withstand high temperatures of 135°C, and has a limiting oxygen index greater than 32, significantly superior to the comparative example. The polyamide cable material provided by this invention possesses excellent temperature resistance and flame retardancy.

[0038] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A polyamide cable compound characterized in that, The raw materials for forming the cable material include, by weight fraction: 100 parts of polyamide, 10-40 parts of nano magnesium hydroxide whiskers, 1-5 parts of silane coupling agent, 1-5 parts of amphiphilic block copolymer, 1-10 parts of pentaerythritol triacrylate, and 1-5 parts of antioxidant; The nano magnesium hydroxide whiskers have a fiber length of 200-1000 nm and a fiber diameter of 30-80 nm.

2. The polyamide cable compound of claim 1, wherein, The polyamide is selected from polyamide 1010; and / or The silane coupling agent is selected from KH550; and / or The amphiphilic block copolymer is selected from polystyrene-b-polyacrylic acid; and / or The antioxidant is selected from one or more of 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and tris[2,4-di-tert-butylphenyl] phosphite.

3. The polyamide cable compound of claim 1 or 2, wherein, The antioxidant is a mixture of 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and tris[2,4-di-tert-butylphenyl] phosphite in a mass ratio of 2:

1.

4. The polyamide cable compound of claim 2, wherein, The polystyrene-b-polyacrylic acid has a molecular weight of 15000-b-1600 g / mol.

5. The polyamide cable compound of claim 1, wherein, The raw materials further include 0-3 parts of halogen-free color masterbatch.

6. The polyamide cable compound of claim 1, wherein, The raw materials for forming the cable material include, by weight fraction: 100 parts of polyamide, 30 parts of nano magnesium hydroxide whiskers, 2 parts of silane coupling agent, 4 parts of amphiphilic block copolymer, 5 parts of pentaerythritol triacrylate, and 3 parts of antioxidant.

7. The polyamide cable compound of claim 1, wherein, In the cable material, the silane coupling agent is grafted on the surface of the nano magnesium hydroxide whiskers, and the lipophilic end of the amphiphilic block copolymer is assembled on the surface of the nano magnesium hydroxide whiskers through the silane coupling agent, and the hydrophilic end is connected to the polyamide.

8. The process for the preparation of polyamide cable compounds according to any one of claims 1 to 7, characterized in that, The method includes the following steps: Under stirring, the silane coupling agent is added to the nano magnesium hydroxide whiskers, and the stirring is continued for 1-3 h for surface modification to obtain nano magnesium hydroxide whiskers grafted with silane coupling agent; The amphiphilic block copolymer is added, and the stirring is continued for 1-3 h to obtain nano magnesium hydroxide whiskers assembled with amphiphilic block copolymer on the surface; The nano magnesium hydroxide whiskers assembled with amphiphilic block copolymer on the surface, polyamide, pentaerythritol triacrylate, and antioxidant are mixed uniformly, and extrusion granulation is performed, thereby obtaining the polyamide cable material.

9. The preparation method according to claim 8, characterized in that, The extrusion granulation is performed in a twin-screw extruder, and the extrusion temperature is 210-240°C.

10. Use of the polyamide cable material according to any one of claims 1-7 in the preparation of a cable.

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