Low-fluorine irradiation crosslinking ethylene-tetrafluoroethylene copolymer insulated wire, preparation method and application thereof

Abstract

The invention discloses a low-fluorine irradiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire, a preparation method and application of the low-fluorine irradiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire. The insulated wire is prepared from the following raw materials in parts by weight: 100 parts of an ethylene-tetrafluoroethylene copolymer, 1 to 10 parts of a cross-linking agent, 1 to 5 parts of 3-aminopropyltriethoxysilane, 0.1 to 1 part of distearyl pentaerythritol diphosphite, 1 to 5 parts of antimony trioxide, 1 to 5 parts of activated zinc oxide, 1 to 5 parts of superfine calcium hydroxide and 1 to 4 parts of an adsorbent. The raw materials are subjected to high-speed stirring, banburying, extrusion forming and radiation crosslinking to prepare the low-fluorine irradiation crosslinking ethylene-tetrafluoroethylene copolymer insulated wire, alkaline substances are added into the low-fluorine irradiation crosslinking ethylene-tetrafluoroethylene copolymer insulated wire, on the basis of keeping excellent performance to the maximum extent, the fluorine escape amount is reduced, and aerospace precision electronic devices are prevented from being corroded.

Description

Technical Field

[0001] The invention relates to the technical field of aviation materials, and in particular to a low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire, a preparation method and application thereof. Background Art

[0002] Ethylene-tetrafluoroethylene polymers (ETFE) are a new type of tetrafluoroethylene copolymer material. ETFE has many advantages such as low density, high toughness, high tensile strength, impact resistance, wear resistance, and insulation performance. The long-term working temperature of ethylene-tetrafluoroethylene copolymer (X-ETFE) after radiation cross-linking can be increased to 200°C. Compared with other fluorine-containing plastics, it has the lightest specific gravity. Due to its high temperature resistance, radiation resistance, and weather resistance, XETFE wires and cables are widely used in the aerospace field, including spacecraft wires, cross-linked irradiated aerospace-grade wires, communication wires, etc., and have gradually become one of the two main types of wires in today's aerospace field.

[0003] Existing X-ETFE wires can meet the use requirements in the aviation field, but in its production process, ETFE will produce a large amount of hydrogen fluoride during the irradiation process, and slowly volatilize in the cable, which will eventually corrode components and cause damage to equipment and instruments. Especially in the field of aerospace, long-term use in a vacuum state will accelerate the volatilization of hydrogen fluoride and corrode electronic equipment components. After accumulating to a certain amount in a closed device, it will not only reduce the reliability of components, but also damage human health. CN105924758A discloses a low-density modified polyethylene-tetrafluoroethylene copolymer insulation material that can be irradiated and cross-linked, and its raw material formula includes polyethylene-tetrafluoroethylene copolymer, ultra-high molecular weight polyethylene, hollow glass microspheres, N, N-bis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 3-aminopropyl triethoxysilane, antimony trioxide, ethylene-tetrafluoroethylene copolymer masterbatch containing polytetrafluoroethylene powder, and zinc stearate. The cross-linked low-density modified ethylene-tetrafluoroethylene copolymer insulating material has the characteristics of low density and low cost, and while retaining the excellent properties of ethylene-tetrafluoroethylene such as high temperature resistance, radiation resistance, and chemical solvent resistance, it improves the strength, heat resistance, and long-term use temperature of ETFE. CN111117044A discloses a low-fluoride emission radiation cross-linked polyethylene-tetrafluoroethylene copolymer insulating material and a preparation method thereof. The insulating material is composed of polyethylene-tetrafluoroethylene copolymer, talcum powder, antimony trioxide, zinc oxide, zinc stearate, hydroxy-2-phenyl-3-pyridone, glycerol behenate, N,N-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 3-aminopropyltriethoxysilane, and a cross-linking agent. The copolymer insulating material of the invention can quickly absorb hydrogen fluoride generated by ETFE insulating material after irradiation, significantly reduce the emission of hydrogen fluoride, and the emission is less than 20ppm, thereby improving the safety and environmental protection of radiation cross-linked ETFE and improving the mechanical properties of the copolymer insulating material. At present, there is still a need to provide a new insulating material that can absorb a large amount of hydrogen fluoride and can be used for a long time on aerospace equipment. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire, a preparation method and its application, which significantly reduces the escape amount of hydrogen fluoride while maintaining the excellent properties of the ethylene-tetrafluoroethylene copolymer.

[0005] The invention provides a low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire, which comprises the following raw materials in parts by weight: 100 parts of ethylene-tetrafluoroethylene copolymer, 1-10 parts of a cross-linking agent, 1-5 parts of 3-aminopropyl triethoxysilane, 0.1-1 parts of distearyl pentaerythritol diphosphite, 1-5 parts of antimony trioxide, 1-5 parts of active zinc oxide, 1-5 parts of ultrafine calcium hydroxide, and 1-4 parts of an adsorbent;

[0006] Wherein, the adsorbent includes 1-2 parts of silicon dioxide and 0.5-1 parts of calcium chloride;

[0007] As a further preferred embodiment of the present invention, the low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire comprises the following raw materials in parts by weight: 100 parts of ethylene-tetrafluoroethylene copolymer, 8 parts of cross-linking agent, 3 parts of 3-aminopropyl triethoxysilane, 0.8 parts of distearyl pentaerythritol diphosphite, 4 parts of antimony trioxide, 5 parts of active zinc oxide, 5 parts of ultrafine calcium hydroxide, and 4 parts of adsorbent;

[0008] Wherein, the adsorbent includes 2 parts of silicon dioxide and 1 part of calcium chloride.

[0009] The crosslinking agent is trimethylolpropane trimethacrylate and triallyl isocyanurate, and the mass ratio of trimethylolpropane trimethacrylate to triallyl isocyanurate is 1:1.5.

[0010] A method for preparing a low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire comprises the following steps:

[0011] (1) placing the adsorbent and the cross-linking agent in a high-speed mixer, dispersing and premixing at a temperature of 80-100° C. and a rotation speed of 800-1200 rpm for 30-50 minutes to ensure that the adsorbent is attached to the surface of the cross-linking agent;

[0012] (2) placing ethylene-tetrafluoroethylene copolymer, active zinc oxide, antimony trioxide, distearyl pentaerythritol diphosphite, ultrafine calcium hydroxide, 3-aminopropyl triethoxysilane and the mixture obtained in step (1) in an internal mixer, mixing and forming, and extruding and granulating with a twin-screw extruder;

[0013] (3) The granulated product is passed through a single screw extruder to be extruded and molded into electric wires.

[0014] (4) The wire obtained in step (3) is subjected to radiation cross-linking to prepare a finished wire, with an irradiation dose of 10-20 Mrad.

[0015] (5) Place the finished product line in an oven for drying.

[0016] Furthermore, in step (2), the rotor speed of the internal mixer is 40-50 rpm, and the mixing is carried out at a temperature of 280° C.-300° C. for 18-20 minutes;

[0017] Furthermore, in step (2), the screw speed of the twin-screw extruder is 30-40 rpm and the temperature is 280° C.-300° C.;

[0018] Furthermore, the feed port temperature of the single screw extruder in step (3) is 270°C;

[0019] Furthermore, the wire in step (3) uses 20-gauge wire, 19 / 0.203 silver-plated wire, a conductor diameter of 0.98 mm, and a cable diameter of 1.27 mm.

[0020] Furthermore, the oven temperature in step (5) is 100° C. and the drying time is 12-16 hours.

[0021] The low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire prepared according to the above raw material ratio and preparation method is used in the field of aerospace.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention provides a low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire and a method for preparing the same. The insulated wire prepared by the method contains an alkaline substance added thereto to react chemically with hydrogen fluoride, which neutralizes the substance and converts it into salt and water, thereby reducing the amount of hydrogen fluoride generated during the irradiation process.

[0024] (2) Modify the alkaline acid absorber by blending. Pre-blend with the cross-linking agent by adding silicon dioxide and calcium chloride. The decomposition temperature of silicon dioxide is above 900°C. It is a high-temperature resistant organic substance that can be adsorbed on the surface of the cross-linking agent and prevent it from reacting with the cross-linking agent.

[0025] (3) The cross-linked ethylene-tetrafluoroethylene copolymer insulated wire prepared according to the method of the present invention has very good thermal stability during the processing, and the color of the finished product does not change after irradiation. The material maintains the excellent performance of ETFE to the greatest extent, and the fluorine emission is less than 20ppm, ensuring the normal life of aviation precision electronic devices. DETAILED DESCRIPTION

[0026] Example 1

[0027] A low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire A comprises the following raw materials in parts by weight: 100 parts of ethylene-tetrafluoroethylene copolymer, 3 parts of a cross-linking agent, 2 parts of 3-aminopropyltriethoxysilane, 0.5 parts of distearyl pentaerythritol diphosphite, 1 part of antimony trioxide, 2 parts of active zinc oxide, 3 parts of ultrafine calcium hydroxide, and 2 parts of an adsorbent, wherein the adsorbent comprises 1 part of silicon dioxide and 0.5 parts of calcium chloride, and the cross-linking agent is trihydroxymethylpropane trimethacrylate and triallyl isocyanurate, and the mass ratio is 1:1.5.

[0028] The preparation method of low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire A is as follows:

[0029] (1) placing the adsorbent silica, calcium chloride and the crosslinking agents trimethylolpropane trimethacrylate and triallyl isocyanurate in a high-speed mixer, pre-mixing them at 100° C. and 1100 rpm for 30 minutes to ensure that the adsorbent adheres to the surface of the crosslinking agent;

[0030] (2) placing ethylene-tetrafluoroethylene copolymer, active zinc oxide, antimony trioxide, distearyl pentaerythritol diphosphite, ultrafine calcium hydroxide, 3-aminopropyltriethoxysilane and the mixture obtained in step (1) in an internal mixer, adjusting the rotor speed of the internal mixer to 40 rpm, mixing at 300° C. for 20 minutes, and then extruding and granulating the mixture using a twin-screw extruder, wherein the screw speed of the twin-screw extruder is 30 rpm and the temperature is 300° C.

[0031] (3) The granulated finished product is extruded into a wire through a single screw extruder, wherein the feed inlet temperature of the single screw extruder is 270° C. The prepared wire uses a 20 gauge wire, 19 / 0.203 silver-plated wire, a conductor diameter of 0.98 mm, and a cable diameter of 1.27 mm.

[0032] (4) The wire obtained in step (3) is subjected to radiation cross-linking using an irradiation dose of 20 Mrad to prepare a finished wire.

[0033] (5) The finished wire is placed in an oven at 100° C. and dried for 12 hours to obtain an insulated wire 1.

[0034] Example 2

[0035] A low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire B comprises the following raw materials in parts by weight: 100 parts of ethylene-tetrafluoroethylene copolymer, 5 parts of a cross-linking agent, 2 parts of 3-aminopropyl triethoxysilane, 0.5 parts of distearyl pentaerythritol diphosphite, 2 parts of antimony trioxide, 2 parts of active zinc oxide, 3 parts of ultrafine calcium hydroxide, and 2 parts of an adsorbent, wherein the adsorbent comprises 1 part of silicon dioxide and 0.5 parts of calcium chloride, and the cross-linking agent is trihydroxymethylpropane trimethacrylate and triallyl isocyanurate, and the mass ratio is 1:1.5.

[0036] The preparation method of low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire B is the same as that of Example 1.

[0037] Example 3

[0038] A low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire C comprises the following raw materials in parts by weight: 100 parts of ethylene-tetrafluoroethylene copolymer, 5 parts of a cross-linking agent, 2 parts of 3-aminopropyl triethoxysilane, 0.5 parts of distearyl pentaerythritol diphosphite, 1 part of antimony trioxide, 2 parts of active zinc oxide, 5 parts of ultrafine calcium hydroxide, and 3 parts of an adsorbent, wherein the adsorbent comprises 1 part of silicon dioxide and 0.5 parts of calcium chloride, and the cross-linking agent is trihydroxymethylpropane trimethacrylate and triallyl isocyanurate, and the mass ratio is 1:1.5.

[0039] The preparation method of low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire C is the same as that of Example 1.

[0040] Example 4

[0041] A low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire D comprises the following raw materials in parts by weight: 100 parts of ethylene-tetrafluoroethylene copolymer, 8 parts of a cross-linking agent, 3 parts of 3-aminopropyl triethoxysilane, 0.8 parts of distearyl pentaerythritol diphosphite, 4 parts of antimony trioxide, 5 parts of active zinc oxide, 5 parts of ultrafine calcium hydroxide, and 4 parts of an adsorbent, wherein the adsorbent comprises 2 parts of silicon dioxide and 1 part of calcium chloride, and the cross-linking agent is trihydroxymethylpropane trimethacrylate and triallyl isocyanurate, and the mass ratio is 1:1.5.

[0042] The preparation method of low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire D is the same as that of Example 1.

[0043] The low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wires A\B\C\D prepared in the above Examples 1 to 4 were tested for fluorine content performance, and the test method was as follows:

[0044] 1. Sample test: Take about 0.5g of insulated wire, cut into 75mm lengths, and weigh (accurate to 0.001g). Weigh a polystyrene test tube (without lid) and weigh it to an accuracy of 0.1g. Place about 14mL of distilled water in the polystyrene test tube and weigh it again. Place the weighed insulated wire in the test tube and completely immerse it in the water, then close the test tube lid. Place the test tube part in a 70℃ constant temperature water bath so that the water surface of the constant temperature water bath is flush with the liquid surface in the test tube. The test tube needs to be placed in the constant temperature water bath for 168h, and check it at regular intervals to ensure that the sample is completely immersed in the water. After the test, remove the test tube from the water bath and place it until room temperature. Open the test tube lid and weigh the test tube, water and sample to determine the water loss. If the mass loss of distilled water exceeds 0.5g, the test must be repeated. Take 5mL of water from the test tube and test the fluoride ion content by ion chromatograph. The fluoride ion content should be converted to ppm.

[0045] 2. Blank test: Perform the test according to step 1, but do not add the sample. Only test tubes and distilled water are tested. Ideally, no fluoride ions should escape from the test tube or distilled water, and the result of fluoride ion escape should be zero. However, it is possible to get a non-zero value (such as 0.005ppm). If this happens, this value must be subtracted from the result when the sample is included. Another function of the blank test is to calibrate the test results. For example, if the result of the blank test is a fluoride ion concentration of 15ppm, this means that the ion chromatograph may not be operating correctly, or tap water is used instead of distilled water for the test, and so on.

[0046] 3. Calculation: If the blank test value is not 0, the fluoride ion escape concentration (ppm) obtained from the blank test should be subtracted from the result obtained from the sample test.

[0047] The fluoride ion release of insulated wires is calculated according to the following formula:

[0048]

[0049] The mechanical properties of insulated wires A\B\C\D were measured, and the results are shown in the following table:

[0050]

[0051]

[0052] According to the results in the above table, compared with the insulated wire A, the fluorine emission of the insulated wire B increased and the elongation at break decreased after increasing the content of the cross-linking agent; after adding the alkaline substance, the fluorine emission of the insulated wire C decreased significantly, and the tensile strength and elongation at break decreased; after adding the dispersant, the insulated wire D had better comprehensive performance, and the fluorine emission was significantly lower than that of the insulated wires A / B / C, indicating that it is more suitable for use in precision electronic components in aviation.

[0053] The specific embodiments are merely explanations of the present application and are not limitations of the present application. After reading this specification, those skilled in the art may make modifications to the embodiments without any creative contribution as needed. However, as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A low-fluorine radiation cross-linked ethylene-tetrafluoroethylene copolymer insulated wire, characterized in that: The method comprises the following raw materials in parts by weight: 100 parts of ethylene-tetrafluoroethylene copolymer, 1-10 parts of a cross-linking agent, 1-5 parts of 3-aminopropyl triethoxysilane, 0.1-1 parts of distearyl pentaerythritol diphosphite, 1-5 parts of antimony trioxide, 1-5 parts of active zinc oxide, 1-5 parts of ultrafine calcium hydroxide, and 1-4 parts of an adsorbent; The adsorbent includes 1-2 parts of silicon dioxide and 0.5-1 parts of calcium chloride.

2. A low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of ethylene-tetrafluoroethylene copolymer, 8 parts of cross-linking agent, 3 parts of 3-aminopropyl triethoxysilane, 0.8 parts of distearyl pentaerythritol diphosphite, 4 parts of antimony trioxide, 5 parts of active zinc oxide, 5 parts of ultrafine calcium hydroxide, and 4 parts of adsorbent; The adsorbent includes 2 parts of silicon dioxide and 1 part of calcium chloride.

3. A low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire according to claim 1, characterized in that: The crosslinking agent is trimethylolpropane trimethacrylate and triallyl isocyanurate, and the mass ratio of trimethylolpropane trimethacrylate to triallyl isocyanurate is 1:1.

5.

4. A method for preparing a low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire, characterized in that: The following steps are involved: S101. The adsorbent and the cross-linking agent are placed in a high-speed mixer and pre-mixed at a temperature of 80-100°C and a speed of 800-1200 rpm for 30-50 minutes to ensure that the adsorbent is attached to the surface of the cross-linking agent; S102. The ethylene-tetrafluoroethylene copolymer, active zinc oxide, antimony trioxide, distearyl pentaerythritol diphosphite, ultrafine calcium hydroxide, 3-aminopropyl triethoxysilane and the mixture obtained in step S101 are placed in an internal mixer, mixed and formed, and extruded and granulated using a twin-screw extruder; S103. The granulated product is extruded through a single screw extruder to prepare an insulated wire; S104. The wire obtained in step S103 is subjected to radiation cross-linking to obtain a finished wire, with an irradiation dose of 10-20 Mrad; S105. Place the finished product line in an oven for drying.

5. The method for preparing a low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire according to claim 4, characterized in that: In step S102, the rotor speed of the internal mixer is 40-50 rpm, the temperature of the internal mixer is 280° C.-300° C., and the mixing time is 18-20 minutes.

6. The method for preparing a low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire according to claim 4, characterized in that: In step S102, the screw speed of the twin-screw extruder is 30-40 rpm, and the temperature is 280° C.-300° C.

7. The method for preparing a low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire according to claim 4, characterized in that: In step S103, the feed port temperature of the single screw extruder is 270°C.

8. The method for preparing a low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire according to claim 4, characterized in that: The oven temperature in step S105 is 100° C. and the drying time is 12-16 hours.

9. Use of the low-fluorine radiation-crosslinked ethylene-tetrafluoroethylene copolymer insulated wire as claimed in claim 1 in the field of aerospace.

Images