Porcelainized low-smoke halogen-free flame-retardant cable material with high oxygen index and preparation method thereof

Abstract

The invention discloses a high-oxygen-index ceramifiable low-smoke halogen-free flame-retardant cable material and a preparation method thereof. The cable material is prepared from the following components in parts by mass: 40 to 50 parts of ethylene-vinyl acetate copolymer, 20 to 30 parts of polyolefin elastomer, 20 to 30 parts of compatilizer, 180 to 210 parts of halogen-free flame retardant, 40 to 60 parts of ceramic forming filler, 2 to 5 parts of silane coupling agent, 1.5 to 3.5 parts of lubricant and 2.5 to 5 parts of antioxidant. The cable material disclosed by the invention is excellent in flame retardant property, and the material is ensured to have very good mechanical property and high oxygen index through synergistic use of the specific compatilizer and the flame retardant; the use of the ceramic forming filler in the material also ensures that a ceramic body with high bending modulus is formed during high-temperature combustion of the material, oxygen and flame are isolated, and the internal non-flame-retardant insulating material is protected; meanwhile, the proportion of the polyolefin elastomer, the ethylene-vinyl acetate copolymer and the compatilizer in the formula ensures that the material has good processability.

Description

Technical Field

[0001] The invention relates to a high oxygen index vitrified low-smoke halogen-free flame-retardant cable material and a preparation method thereof, belonging to the technical field of cable materials. Background Art

[0002] With the development of society and the economy, the number of large-scale industrial facilities, high-rise commercial buildings, underground structures, and residential buildings has gradually increased. Consequently, the total amount of cables used is increasing, and the density of cables laid is also increasing. Electrical fires caused by aging cables, short circuits, spontaneous combustion, and cable ignition are becoming more frequent, resulting in increasingly serious losses. Low-smoke, halogen-free, flame-retardant sheathing materials are often used in cables in the construction industry due to their environmental advantages, such as low smoke density and low toxicity.

[0003] Low smoke halogen-free sheath material is an environmentally friendly cable sheath material usually composed of thermoplastic or thermosetting polymer materials that produce low smoke when heated and do not contain halogen. It releases low smoke when burned and does not contain halogen elements, so it does not produce toxic hydrogen halide gas and has little impact on the environment and human health.

[0004] Traditional low-smoke, halogen-free, flame-retardant polyolefins achieve flame retardancy by adding large amounts of halogen-free flame-retardant fillers. However, the large addition of flame retardants can significantly degrade the material's mechanical properties. Furthermore, the addition of large amounts of metal hydroxides to enhance the flame retardancy of sheath materials has limitations. The oxide layer formed by the decomposition of metal hydroxides is not dense enough, and the resulting shell after carbonization has weak bending strength and poor fire and oxygen barrier properties. Summary of the Invention

[0005] The purpose of the present invention is to provide a high oxygen index vitrified low smoke halogen-free flame retardant cable material and a preparation method thereof in view of the deficiencies in the prior art.

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

[0007] The present invention provides a high oxygen index porcelain-type low-smoke halogen-free flame-retardant cable material. The cable material comprises the following raw material components and proportions: 40 to 50 parts by mass of ethylene-vinyl acetate copolymer, 20 to 30 parts by mass of polyolefin elastomer, 20 to 30 parts by mass of compatibilizer, 180 to 210 parts by mass of halogen-free flame retardant, 40 to 60 parts by mass of porcelain-forming filler, 2 to 5 parts by mass of silane coupling agent, 1.5 to 3.5 parts by mass of lubricant and 2.5 to 5 parts by mass of antioxidant.

[0008] Preferably, the melt index of the ethylene-vinyl acetate copolymer is 3 to 10 g / 10 min, and the vinyl acetate monomer content of the ethylene-vinyl acetate copolymer is 26 to 40 wt%.

[0009] Preferably, the melt index of the polyolefin elastomer is 1 to 5 g / 10 min.

[0010] Preferably, the compatibilizer is one or both of maleic anhydride grafted polyolefin elastomer and maleic anhydride grafted polyethylene, and the melt index of the compatibilizer is 2-4 g / 10 min.

[0011] Preferably, the halogen-free flame retardant is one or more of aluminum hydroxide, magnesium hydroxide, diethyl aluminum hypophosphite, melamine cyanurate, and ammonium polyphosphate.

[0012] Preferably, the ceramic filler is one or more of zinc borate, glass powder, titanium dioxide, silicon dioxide, wollastonite, and montmorillonite.

[0013] Preferably, the lubricant is one or more of zinc stearate, calcium stearate, EBS (ethylene bisstearamide), and polyethylene wax.

[0014] Preferably, the antioxidant is one or more of antioxidant 168 (tris[2,4-di-tert-butylphenyl]phosphite), antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), and antioxidant DSTP (distearate thiodipropionate).

[0015] Preferably, the silane coupling agent includes one or both of vinyltriethoxysilane and vinyltrimethoxysilane.

[0016] The present invention also provides a method for preparing the cable material as described above, comprising: adding ethylene-vinyl acetate copolymer, polyolefin elastomer, compatibilizer, halogen-free flame retardant filler, porcelain-forming filler, silane coupling agent, lubricant and antioxidant weighed in proportion by weight into an internal mixer and mixing, discharging the material when the material temperature reaches 170-185°C, then shearing and mixing through a twin-screw extruder, and granulating through a single-screw extruder to obtain the low-smoke halogen-free flame retardant cable material.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The high-oxygen-index vitrified low-smoke halogen-free flame-retardant cable material provided by the present invention has excellent flame-retardant properties. By adding a specific compatibilizer and using it in conjunction with a flame retardant, the material is ensured to have good mechanical properties and a high oxygen index. The use of a porcelain-forming filler in the material also ensures that the material forms a ceramic body with a high bending modulus when burned at high temperatures, isolating oxygen and flames and protecting the internal non-flame-retardant insulating material. At the same time, the ratio of the polyolefin elastomer, ethylene-vinyl acetate copolymer and compatibilizer in the formula ensures that the material has good processing properties. DETAILED DESCRIPTION

[0019] The embodiments of the present invention will be described in detail below with reference to the examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0020] Unless otherwise specified, the raw materials and reagents used in the following examples were all purchased from commercial sources.

[0021] In the following examples, the melt index of ethylene-vinyl acetate copolymer is 2-4 g / 10 min, and the vinyl acetate monomer content is 26-33 wt%; the melt index of polyolefin elastomer is 1-5 g / 10 min, purchased from Dow Chemical, POE8200; maleic anhydride grafted polyolefin elastomer is purchased from Kingfa Technology; maleic anhydride grafted polyethylene is purchased from Nengzhiguang New Materials Technology; aluminum hydroxide, with an average particle size of 2 microns, is purchased from Zhongshun Henghui (Binzhou) New Materials Co., Ltd.; silane coupling agent vinyl triethoxysilane (A151) is purchased from Qufu Yishun Chemical.

[0022] Example 1

[0023] A high oxygen index vitrified low-smoke halogen-free flame-retardant cable material, comprising the following raw materials in parts by weight:

[0024] 40 parts of ethylene-vinyl acetate copolymer, 30 parts of polyolefin elastomer, 30 parts of compatibilizer, 210 parts of halogen-free flame retardant, 45 parts of porcelain filler, 2 parts of silane coupling agent A151, 1 part of lubricant vinyl bisstearamide, 1 part of calcium stearate, 0.5 parts of antioxidant 168, and 2 parts of antioxidant 1010.

[0025] The compatibilizer is composed of maleic anhydride modified polyolefin elastomer and maleic anhydride modified polyethylene in a weight ratio of 1:1.

[0026] The halogen-free flame retardant is composed of magnesium hydroxide, diethyl aluminum hypophosphite and ammonium polyphosphate in a weight ratio of 36:5:1.

[0027] The porcelain-forming filler is composed of zinc borate, titanium dioxide and wollastonite in a weight ratio of 5:1:3.

[0028] The method for preparing the high oxygen index vitrified low-smoke halogen-free flame-retardant cable material comprises the following steps:

[0029] According to the raw material formula, ethylene-vinyl acetate copolymer, polyolefin elastomer, compatibilizer, halogen-free flame retardant, porcelain filler, silane coupling agent, lubricant and antioxidant are weighed and added into an internal mixer and mixed to a temperature of 180°C. After the internal mixing, the mixture is mixed by a twin-screw extruder and granulated by a single-screw extruder to obtain the low-smoke halogen-free flame retardant cable material.

[0030] Example 2

[0031] A high oxygen index vitrified low-smoke halogen-free flame-retardant cable material, comprising the following raw materials in parts by weight:

[0032] 40 parts of ethylene-vinyl acetate copolymer, 25 parts of polyolefin elastomer, 35 parts of compatibilizer, 210 parts of halogen-free flame retardant, 45 parts of porcelain filler, 5 parts of silane coupling agent, 0.5 parts of vinyl bisstearamide, 2 parts of zinc stearate, 0.5 parts of antioxidant 168 and 2 parts of antioxidant 1010.

[0033] The compatibilizer is the same as that in Example 1, and the halogen-free flame retardant is the same as that in Example 1.

[0034] The porcelain-forming filler is composed of glass powder, titanium dioxide and wollastonite in a weight ratio of 4:1:4.

[0035] The preparation method of the high oxygen index vitrified low-smoke halogen-free flame-retardant cable material is the same as that of Example 1.

[0036] Example 3

[0037] A high oxygen index vitrified low-smoke halogen-free flame-retardant cable material, comprising the following raw materials in parts by weight:

[0038] 40 parts of ethylene-vinyl acetate copolymer, 30 parts of polyolefin elastomer, 30 parts of compatibilizer, 195 parts of halogen-free flame retardant, 45 parts of porcelain filler, 3 parts of silane coupling agent, 1 part of zinc stearate, 0.5 parts of vinyl bisstearamide, 0.5 parts of antioxidant DSTP, and 2 parts of antioxidant 1010.

[0039] The compatibilizers are all maleic anhydride modified polyethylene.

[0040] The halogen-free flame retardant is composed of aluminum hydroxide, diethyl aluminum hypophosphite and melamine cyanurate in a weight ratio of 34:4:1.

[0041] The ceramic filler is the same as that in Example 2.

[0042] The preparation method of the high oxygen index vitrified low-smoke halogen-free flame-retardant cable material is the same as that of Example 1.

[0043] Example 4

[0044] A high oxygen index vitrified low-smoke halogen-free flame-retardant cable material, comprising the following raw materials in parts by weight:

[0045] 45 parts of ethylene-vinyl acetate copolymer, 30 parts of polyolefin elastomer, 25 parts of compatibilizer, 195 parts of halogen-free flame retardant, 45 parts of porcelain filler, 3 parts of silane coupling agent, 1 part of zinc stearate, 0.5 parts of vinyl bisstearamide, 0.5 parts of antioxidant 168 and 2 parts of antioxidant 1010.

[0046] The compatibilizer is composed of maleic anhydride modified polyolefin elastomer and maleic anhydride modified polyethylene in a weight ratio of 2:3.

[0047] The halogen-free flame retardant is the same as that in Example 3. The ceramic-forming filler is the same as that in Example 2.

[0048] The preparation method of the high oxygen index vitrified low-smoke halogen-free flame-retardant cable material is the same as that of Example 1.

[0049] Example 5

[0050] A high oxygen index vitrified low-smoke halogen-free flame-retardant cable material, comprising the following raw materials in parts by weight:

[0051] 40 parts of ethylene-vinyl acetate copolymer, 30 parts of polyolefin elastomer, 30 parts of compatibilizer, 185 parts of halogen-free flame retardant, 35 parts of porcelain filler, 3 parts of silane coupling agent, 1 part of zinc stearate, 0.5 parts of vinyl bisstearamide, 0.5 parts of antioxidant 168, and 2 parts of antioxidant DSTP.

[0052] The compatibilizer is the same as that in Example 1.

[0053] The halogen-free flame retardant is composed of aluminum hydroxide, diethyl aluminum hypophosphite and melamine cyanurate in a weight ratio of 34:2:1.

[0054] The porcelain-forming filler is composed of zinc borate, titanium dioxide and wollastonite in a weight ratio of 2:1:4.

[0055] The preparation method of the high oxygen index vitrified low-smoke halogen-free flame-retardant cable material is the same as that of Example 1.

[0056] Example 6

[0057] A high oxygen index vitrified low-smoke halogen-free flame-retardant cable material, comprising the following raw materials in parts by weight:

[0058] 40 parts of ethylene-vinyl acetate copolymer, 30 parts of polyolefin elastomer, 30 parts of compatibilizer, 195 parts of halogen-free flame retardant, 45 parts of porcelain filler, 3 parts of silane coupling agent, 1 part of zinc stearate, 0.5 parts of vinyl bisstearamide, 0.5 parts of antioxidant DSTP, and 2 parts of antioxidant 168.

[0059] The compatibilizer is the same as that in Example 1.

[0060] The halogen-free flame retardant is the same as that in Example 3.

[0061] The porcelain-forming filler is composed of zinc borate, titanium dioxide, silicon dioxide and wollastonite in a weight ratio of 4:1:1:3.

[0062] The preparation method of the high oxygen index vitrified low-smoke halogen-free flame-retardant cable material is the same as that of Example 1.

[0063] Comparative Example 1

[0064] A low-smoke, halogen-free, flame-retardant cable material was prepared according to the formula and method of Example 1, with the only difference being that the zinc borate in the porcelain-forming filler in Example 1 was replaced with a halogen-free flame retardant.

[0065] Comparative Example 2

[0066] A low-smoke, halogen-free, flame-retardant cable material was prepared according to the formula and method of Example 1, with the only difference being that the compatibilizer in Example 1 was replaced with linear low-density polyethylene.

[0067] Comparative Example 3

[0068] A low-smoke, halogen-free, flame-retardant cable material was prepared according to the formula and method of Example 1, with the only difference being that the polyolefin elastomer in Example 1 was replaced by linear low-density polyethylene.

[0069] The flame retardant properties and mechanical properties of the cable materials prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were tested respectively. The test results are shown in Table 1.

[0070] Table 1 Performance test results of cable materials of Examples 1 to 6 and Comparative Examples 1 to 3

[0071]

[0072]

[0073] Combined with the data in Table 1, it can be seen from the comparison between Example 1 and Comparative Example 1 that the cable material of Example 1 has a higher oxygen index and better flame retardant properties. In the formula of the low-smoke halogen-free flame retardant cable material of the present application, ceramic fillers such as zinc borate and glass powder can help the cable material form a hard and dense ceramic shell when burning, thereby improving the flame retardant ability of the material.

[0074] Combining the data in Table 1, it can be seen that the cable material of Example 1 of the present application has better tensile strength and elongation at break than Comparative Examples 2 and 3. The compatibilizer and polyolefin elastomer selected in the low-smoke, halogen-free, flame-retardant cable material formulation of the present application can significantly improve the material's mechanical strength and elongation at break. Similarly, the compatibilizer and polyolefin elastomer can improve the dispersibility of the flame-retardant filler in the resin system, thereby improving the material's mechanical strength and elongation at break while also maintaining a high oxygen index.

[0075] The above description is only a preferred embodiment of the present invention and does not constitute any formal or substantial limitation to the present invention. It should be noted that ordinary technicians in this technical field can make several improvements and supplements without departing from the present invention, and these improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A high oxygen index vitrified low smoke halogen-free flame retardant cable material, characterized in that: The cable material includes raw material components in the following proportions: 40 to 50 parts by mass of ethylene-vinyl acetate copolymer, 20 to 30 parts by mass of polyolefin elastomer, 20 to 30 parts by mass of compatibilizer, 180 to 210 parts by mass of halogen-free flame retardant, 40 to 60 parts by mass of porcelain-forming filler, 2 to 5 parts by mass of silane coupling agent, 1.5 to 3.5 parts by mass of lubricant and 2.5 to 5 parts by mass of antioxidant.

2. The cable material according to claim 1, characterized in that: The melt index of the ethylene-vinyl acetate copolymer is 3-10 g / 10 min, and the vinyl acetate monomer content of the ethylene-vinyl acetate copolymer is 26-40 wt%.

3. The cable material according to claim 1, characterized in that: The melt index of the polyolefin elastomer is 1-5 g / 10 min.

4. The cable material according to claim 1, characterized in that The compatibilizer is one or both of maleic anhydride grafted polyolefin elastomer and maleic anhydride grafted polyethylene, and the melt index of the compatibilizer is 2-4 g / 10 min.

5. The cable material according to claim 1, characterized in that: The halogen-free flame retardant is one or more of aluminum hydroxide, magnesium hydroxide, diethyl aluminum hypophosphite, melamine cyanurate, and ammonium polyphosphate.

6. The cable material according to claim 1, characterized in that: The ceramic filler is one or more of zinc borate, glass powder, titanium dioxide, silicon dioxide, wollastonite, and montmorillonite.

7. The cable material according to claim 1, characterized in that: The lubricant is one or more of zinc stearate, calcium stearate, EBS (ethylene bisstearamide), and polyethylene wax.

8. The cable material according to claim 1, characterized in that: The antioxidant is one or more of antioxidant 168 (tris[2,4-di-tert-butylphenyl]phosphite), antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), and antioxidant DSTP (distearate thiodipropionate).

9. The cable material according to claim 1, characterized in that: The silane coupling agent includes one or both of vinyltriethoxysilane and vinyltrimethoxysilane.

10. The method for preparing a cable material according to any one of claims 1 to 9, characterized in that: include: The ethylene-vinyl acetate copolymer, polyolefin elastomer, compatibilizer, halogen-free flame retardant filler, porcelain-forming filler, silane coupling agent, lubricant and antioxidant weighed in proportion by weight are put into an internal mixer for mixing. The material is discharged when the material temperature reaches 170-185°C, and then sheared and mixed by a twin-screw extruder and granulated by a single-screw extruder to obtain the low-smoke halogen-free flame retardant cable material.

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