Flame-retardant wear-resistant heat-shrinkable sleeve and preparation method thereof

Abstract

The flame-retardant wear-resistant heat-shrinkable sleeve is prepared from the following raw materials in parts by weight: 30-50 parts of an ethylene-acetic ether copolymer, 20-40 parts of nitrile rubber, 10-15 parts of polytetrafluoroethylene, 25 parts of polyethylene resin, 5-15 parts of a compatilizer, 3-8 parts of a material reinforcing agent, 1-5 parts of a silane coupling agent, 40-80 parts of a flame retardant, 1-3 parts of an antioxidant, 0.5-1 part of a lubricant and 1-3 parts of an assistant crosslinker. Comprising the following steps: premixing nitrile rubber, namely premixing 25 parts of nitrile rubber, 5 parts of reinforcing material and 2 parts of silane coupling on an open mill to obtain nitrile rubber compound; on the basis of certain flexibility, the wear resistance of the material is enhanced, and meanwhile, the material also has relatively good flame retardant property.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and more specifically, to a flame-retardant and wear-resistant heat shrinkable sleeve and a preparation method thereof. Background Art

[0002] In some application scenarios of heat shrink tubing materials, due to frequent friction and wear, the wear resistance of heat shrink tubing is particularly important. For example, in locations such as automotive wiring harnesses and moving parts of mechanical equipment, heat shrink tubing needs to have good wear resistance to extend its service life.

[0003] Conventional polyolefin heat shrink tubing has poor wear resistance, while heat shrink tubing made of fluorine-containing materials has relatively high hardness and poor flexibility.

[0004] In summary, a flame retardant, wear-resistant and heat shrinkable material is developed so that it has excellent flame retardant and wear-resistant properties while maintaining good comprehensive properties such as mechanical properties, insulation properties and heat shrinkage properties, and has a simple and feasible preparation method to meet the needs of industrial production. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a flame-retardant and wear-resistant heat shrinkable sleeve and a preparation method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A flame-retardant and wear-resistant heat shrinkable tubing, composed of the following raw materials in parts by weight:

[0008] 30-50 parts of ethylene-vinyl acetate copolymer, 20-40 parts of nitrile rubber, 10-15 parts of polytetrafluoroethylene, 25 parts of polyethylene resin, 5-15 parts of compatibilizer, 3-8 parts of material reinforcing agent, 1-5 parts of silane coupling agent, 40-80 parts of flame retardant, 1-3 parts of antioxidant, 0.5-1 parts of lubricant and 1-3 parts of cross-linking aid.

[0009] In a preferred embodiment, the Mooney viscosity of the nitrile rubber is 45MU.

[0010] In a preferred embodiment, the ethylene-vinyl acetate copolymer has a VA content of 28%.

[0011] In a preferred embodiment, the polyethylene resin is ultra high molecular weight polyethylene.

[0012] In a preferred embodiment, the material reinforcing agent is nano-scale fumed silica.

[0013] In a preferred embodiment, the flame retardant is a compound of one or both of melamine cyanurate and aluminum hydroxide.

[0014] In a preferred embodiment, the lubricant is PE wax and silicone masterbatch, and the addition amount is 1:2, the silicone content of the silicone masterbatch is not less than 60%, and the carrier is EVA.

[0015] The present invention also provides a method for preparing a flame retardant and wear-resistant heat shrinkable sleeve, comprising the following steps:

[0016] 1) Premixing of nitrile rubber: 25 parts of nitrile rubber, 5 parts of reinforcing material and 2 parts of silane coupling are premixed on an open mill to obtain a nitrile rubber compound.

[0017] 2) The rubber compound obtained in step 1, 40 parts of ethylene-vinyl acetate copolymer, 15 parts of polyethylene resin, 10 parts of polytetrafluoroethylene, 80 parts of flame retardant, 2 parts of antioxidant, and 1.5 parts of cross-linking agent are put into an internal mixer for mixing, and then subjected to single-screw extrusion and twin-screw extrusion granulation steps to prepare a flame-retardant, wear-resistant, heat-shrinkable masterbatch.

[0018] 3) Extruding the masterbatch particles obtained in step 2) into a tube on an extruder, and then irradiating and cross-linking the extruded tube through an electron accelerator;

[0019] 4) After cross-linking, the pipe is preheated on an expander to heat the heat shrinkable tube to a higher temperature, and then the expander is used to expand it with external force to obtain a flame retardant and wear-resistant shrinkable sleeve.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The invention combines the two and enhances the wear resistance of the material on the basis of certain softness, and also has good flame retardant performance.

[0022] The wear resistance of the material can be improved by adjusting the base resin and optimizing the filler. Some fluorine-containing resins have higher hardness and better scratch resistance, such as PVDF, PTFE, etc.

[0023] Nano-scale fillers such as nano-alumina and nano-silicon dioxide can be evenly dispersed in polymer materials due to their small particle size and large specific surface area, forming a good interface bond with the matrix resin, thereby improving the wear resistance of the material.

[0024] Nanofillers can also enhance the hardness and strength of the material, further improving wear resistance.

[0025] In addition, the heat shrink tubing also needs to have certain flame retardant properties, and be able to self-extinguish without burning at high temperatures even at 600°C, effectively slowing down the spread of flames and protecting people's lives and property. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] Embodiment 1:

[0028] Example 1 comprises the following steps:

[0029] 1) Premixing of nitrile rubber: 25 parts of nitrile rubber, 5 parts of reinforcing material and 2 parts of silane coupling are premixed on an open mill to obtain a nitrile rubber compound.

[0030] 2) The rubber compound obtained in step 1, 40 parts of ethylene-vinyl acetate copolymer, 15 parts of polyethylene resin, 10 parts of polytetrafluoroethylene, 80 parts of flame retardant, 3 parts of antioxidant, and 1.5 parts of cross-linking agent are put into an internal mixer for mixing, and then subjected to single-screw extrusion and twin-screw extrusion granulation steps to prepare a flame-retardant, wear-resistant, heat-shrinkable masterbatch.

[0031] 3) Extruding the masterbatch particles obtained in step 2) into a tube on an extruder, and then irradiating and cross-linking the extruded tube through an electron accelerator;

[0032] 4) After cross-linking, the pipe is preheated on an expander to heat the heat shrinkable tube to a higher temperature, and then the expander is used to expand it with external force to obtain a flame retardant and wear-resistant shrinkable sleeve.

[0033] Embodiment 2:

[0034] Example 2 comprises the following steps:

[0035] 1) Premixing of nitrile rubber: 20 parts of nitrile rubber, 4 parts of reinforcing material and 2 parts of silane coupling are premixed on an open mill to obtain a nitrile rubber compound. The mixing temperature is 50-60°C.

[0036] 2) The rubber compound obtained in step 1, 45 parts of ethylene-vinyl acetate copolymer, 15 parts of polyethylene resin, 10 parts of polytetrafluoroethylene, 80 parts of flame retardant, 3 parts of antioxidant, and 1.5 parts of cross-linking agent are put into an internal mixer for mixing, and then subjected to single-screw extrusion and twin-screw extrusion granulation steps to prepare a flame-retardant, wear-resistant, heat-shrinkable masterbatch.

[0037] 3) Extruding the masterbatch particles obtained in step 2) into a tube on an extruder, and then irradiating and cross-linking the extruded tube through an electron accelerator;

[0038] 4) After cross-linking, the pipe is preheated on an expander to heat the heat shrinkable tube to a higher temperature, and then the expander is used to expand it with external force to obtain a flame retardant and wear-resistant shrinkable sleeve.

[0039] Embodiment 3:

[0040] Example 3 comprises the following steps:

[0041] 1) Premixing of nitrile rubber: 20 parts of nitrile rubber, 4 parts of reinforcing material and 2 parts of silane coupling are premixed on an open mill to obtain a nitrile rubber compound. The mixing temperature is 50-60°C.

[0042] 2) The rubber compound obtained in step 1, 40 parts of ethylene-vinyl acetate copolymer, 15 parts of polyethylene resin, 15 parts of polytetrafluoroethylene, 80 parts of flame retardant, 3 parts of antioxidant, and 1.5 parts of cross-linking agent are put into an internal mixer for mixing, and then subjected to single-screw extrusion and twin-screw extrusion granulation steps to prepare a flame-retardant, wear-resistant, heat-shrinkable masterbatch.

[0043] 3) Extruding the masterbatch particles obtained in step 2) into a tube on an extruder, and then irradiating and cross-linking the extruded tube through an electron accelerator;

[0044] 4) After cross-linking, the pipe is preheated on an expander to heat the heat shrinkable tube to a higher temperature, and then the expander is used to expand it with external force to obtain a flame retardant and wear-resistant shrinkable sleeve.

[0045] Embodiment 4:

[0046] Example 4 comprises the following steps:

[0047] 1) Premixing of nitrile rubber: 20 parts of nitrile rubber, 4 parts of reinforcing material and 2 parts of silane coupling are premixed on an open mill to obtain a nitrile rubber compound. The mixing temperature is 50-60°C.

[0048] 2) The rubber compound obtained in step 1, 40 parts of ethylene-vinyl acetate copolymer, 20 parts of polyethylene resin, 10 parts of polytetrafluoroethylene, 80 parts of flame retardant, 3 parts of antioxidant, and 1.5 parts of cross-linking agent are put into an internal mixer for mixing, and then subjected to single-screw extrusion and twin-screw extrusion granulation steps to prepare a flame-retardant, wear-resistant, heat-shrinkable masterbatch.

[0049] 3) Extruding the masterbatch particles obtained in step 2) into a tube on an extruder, and then irradiating and cross-linking the extruded tube through an electron accelerator;

[0050] 4) After cross-linking, the pipe is preheated on an expander to heat the heat shrinkable tube to a higher temperature, and then the expander is used to expand it with external force to obtain a flame retardant and wear-resistant shrinkable sleeve.

[0051] Comparative Example:

[0052] The formula is as follows: 55 parts of ethylene-vinyl acetate copolymer, 30 parts of polyethylene resin, 15 parts of compatibilizer, 80 parts of flame retardant, 3 parts of antioxidant, and 1.5 parts of cross-linking agent. The processing process is consistent with the steps of the embodiment.

[0053] data:

[0054] Example 1 Example 2 Example 3 Example 4 Comparative Example Limiting oxygen index % 34 33 33.5 34.2 28.5 Tensile Strength MPa ＞13 ＞13 ＞13 ＞13 ＞13 Elongation at break % ＞300 ＞300 ＞300 ＞300 ＞300 hardness Shao A 93 93 95 94 95 Volumetric wear <![CDATA[mm 3 ]]> 1.23 1.01 0.96 2.13 8.24 surface Smooth and flat Smooth and flat Smooth and flat Smooth and flat Smooth and flat

[0055] The oxygen index is tested in accordance with GB / T 2406-2022. The tensile properties are tested in accordance with GB / T 1040.1-2018 Plastic Tensile Properties. The wear resistance is tested in accordance with GB / T 3960-2016, with a pressure of 200N, a rotation speed of 196rpm, and a cycle of 2h. The hardness is tested in accordance with the Shore A hardness in GB / T 531-1999.

[0056] These experimental data show that the flame-retardant and wear-resistant heat shrinkable tubing and the preparation method thereof of the present invention can obtain a material with good comprehensive properties, which meets the requirements of flame retardancy, mechanical properties, insulation properties, heat shrinkage properties and the like.

[0057] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that, for those skilled in the art, the described embodiments can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the above description is illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A flame retardant and wear-resistant heat shrink tubing, characterized in that: It is composed of the following raw materials in parts by weight: 30-50 parts of ethylene-vinyl acetate copolymer, 20-40 parts of nitrile rubber, 10-15 parts of polytetrafluoroethylene, 25 parts of polyethylene resin, 5-15 parts of compatibilizer, 3-8 parts of material reinforcing agent, 1-5 parts of silane coupling agent, 40-80 parts of flame retardant, 1-3 parts of antioxidant, 0.5-1 parts of lubricant and 1-3 parts of cross-linking aid.

2. The flame-retardant and wear-resistant heat shrink tubing according to claim 1, characterized in that: The Mooney viscosity of the nitrile rubber is 45MU.

3. The flame-retardant and wear-resistant heat shrink tubing according to claim 1, characterized in that: The ethylene-vinyl acetate copolymer has a VA content of 28%.

4. The flame-retardant and wear-resistant heat shrink tubing according to claim 1, characterized in that: The polyethylene resin is ultra-high molecular weight polyethylene.

5. The flame-retardant and wear-resistant heat shrink tubing according to claim 1, characterized in that: The material reinforcing agent is nano-scale fumed silica.

6. The flame-retardant and wear-resistant heat shrink tubing according to claim 1, characterized in that: The flame retardant is a compound of one or two of melamine cyanurate and aluminum hydroxide.

7. The flame-retardant and wear-resistant heat shrink tubing according to claim 1, characterized in that: The lubricant is PE wax and silicone masterbatch, and the addition amount is 1:

2. The silicone content of the silicone masterbatch is not less than 60%, and the carrier is EVA.

8. A method for preparing a flame-retardant and wear-resistant heat shrinkable tubing, characterized in that: The following steps are involved: 1) Premixing of nitrile rubber: 25 parts of nitrile rubber, 5 parts of reinforcing material and 2 parts of silane coupling are premixed on an open mill to obtain a nitrile rubber compound; 2) The rubber compound obtained in step 1, 40 parts of ethylene-vinyl acetate copolymer, 15 parts of polyethylene resin, 10 parts of polytetrafluoroethylene, 80 parts of flame retardant, 2 parts of antioxidant, and 1.5 parts of cross-linking agent are put into an internal mixer for mixing, and then subjected to single-screw extrusion and twin-screw extrusion granulation steps to prepare a flame-retardant, wear-resistant, heat-shrinkable masterbatch; 3) Extruding the masterbatch particles obtained in step 2) into a tube on an extruder, and then irradiating and cross-linking the extruded tube through an electron accelerator; 4) After cross-linking, the pipe is preheated on an expander to heat the heat shrinkable tube to a higher temperature, and then the expander is used to expand it with external force to obtain a flame retardant and wear-resistant shrinkable sleeve.