Ultralow-smoke-density cold-resistant halogen-free flame-retardant cable material and preparation method therefor

Abstract

Disclosed in the present invention are an ultralow-smoke-density cold-resistant halogen-free flame-retardant cable material and a preparation method therefor. The cable material is prepared from the following raw materials in parts by mass: 50 parts of a base resin, 45-80 parts of an inorganic flame retardant, 1-3 parts of a lubricant, 2-4 parts of a reactive smoke suppressant, 0.2-0.5 part of an antioxidant, 2-5 parts of zinc borate and 1-2 parts of a coupling agent, the base resin comprising an ethylene-vinyl acetate copolymer, a maleic anhydride grafted polymer and a metallocene linear polyethylene resin in a mass ratio of (25-35):(5-10):(10-20), and the inorganic flame retardant being a mixture of modified aluminum-magnesium hydrotalcite and modified magnesium hydroxide. The inorganic flame retardant used in the present invention has dual effects of flame retardance and smoke elimination, so that in cooperation with the reactive smoke suppressant, the cable material can reach an ultralow smoke density during combustion. In addition, none of the base resin, the inorganic flame retardant and the reactive smoke suppressant contains a halogen component, so that no halogen gas will be generated during combustion. The base resin has a reasonable proportion, so that the cable material can tolerate a low temperature of -40℃.

Description

Ultra-low smoke density cold-resistant halogen-free flame-retardant cable material and preparation method thereof Technical Field

[0001] The present invention relates to a low-smoke halogen-free flame-retardant cable material, in particular to an ultra-low smoke density cold-resistant halogen-free flame-retardant cable material. Background Art

[0002] Modern society is inseparable from electricity, and its use is inseparable from power cables. Inevitably, cables present a fire risk during use due to various factors. The combustion of ordinary cables is generally accompanied by the production of large amounts of smoke, which pollutes the environment and causes significant harm to the human body. This is especially true in indoor environments, where a large number of deaths in fires are related to smoke asphyxiation. Polyvinyl chloride (PVC) is widely used in cable production due to its low price and superior performance. However, when PVC burns, it produces toxic fumes such as hydrogen chloride and hydrogen sulfide. In the event of a fire, these fumes can be fatal to those affected. Therefore, the use of halogen-free and low-smoke cables is explicitly required in most densely populated areas.

[0003] On the other hand, in my country's northwest region, the climate is cold and dry, with long, low winters, placing specific demands on the cold resistance of cables. Ordinary national standard cables can only withstand temperatures as low as -15°C, while winter temperatures in regions like Ningxia and Shaanxi can drop as low as -30°C. Ordinary cables will become brittle and crack, seriously shortening their service life and causing great inconvenience to people's production and daily life.

[0004] Therefore, a cable material that is low smoke, low halogen, flame retardant and cold resistant is needed to meet social needs. Although cable materials with single good low smoke, flame retardant or cold resistance are very common now, cable materials with comprehensive low smoke, low halogen, flame retardant and cold resistance are still in urgent need of development.

[0005] Summary of the Invention

[0006] In response to the problem that current cable materials cannot simultaneously possess good low smoke, flame retardancy and cold resistance, the present invention provides an ultra-low smoke density cold-resistant halogen-free flame retardant cable material. The cable material has excellent smoke suppression and flame retardant properties, does not produce a large amount of halogen acid gas when burned, and maintains good mechanical properties and cold resistance.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] Disclosed is an ultra-low smoke density, cold-resistant, halogen-free flame-retardant cable material, which is prepared from the following raw materials, calculated by weight: 50 parts of a base resin, 45-80 parts of an inorganic flame retardant, 1-3 parts of a lubricant, 2-4 parts of a reactive smoke suppressant, 0.2-0.5 parts of an antioxidant, 2-5 parts of zinc borate, and 1-2 parts of a coupling agent; the base resin comprises an ethylene-vinyl acetate copolymer, a maleic anhydride graft, and a metallocene linear polyethylene resin in a mass ratio of (25-35):(5-10):(10-20); and the inorganic flame retardant is a mixture of modified aluminum-magnesium hydrotalcite and modified magnesium hydroxide.

[0009] The inorganic flame retardant used in the present invention has high-efficiency flame retardant and smoke suppression effects, and produces very little smoke during combustion. In addition, the base resin and reactive smoke suppressant used do not contain halogen components, so that the cable material does not produce halogen gas when it burns. The ratio of the base resin can enable the cable material to withstand low temperatures of -40°C.

[0010] Preferably, the mass ratio of the modified aluminum-magnesium hydrotalcite to the modified magnesium hydroxide is (1-2):1.

[0011] Preferably, the modification method of the modified aluminum-magnesium hydrotalcite is: mixing the aluminum-magnesium hydrotalcite with 1.0-1.5 wt% of stearic acid at a mixing temperature of 75-80° C. and a mixing time of 60-120 min.

[0012] Preferably, the modification method of the modified magnesium hydroxide is: drying the magnesium hydroxide at 100-110° C. for 1 hour, and then mixing it with 1.0-1.5 wt% of stearic acid at a mixing temperature of 100-105° C. for 30 minutes.

[0013] Preferably, the lubricant is pentaerythritol stearate and / or silicone masterbatch.

[0014] Preferably, the reactive smoke suppressant is melamine cyanurate and / or ammonium polyphosphate.

[0015] Preferably, the antioxidant is antioxidant 1010 and / or antioxidant DLTP.

[0016] Preferably, the particle size of the zinc borate is 1 to 3 μm.

[0017] Preferably, the coupling agent is a blend of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and isopropyl di(methacryloyl) isostearyl titanate.

[0018] Preferably, the mass ratio of the N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, the γ-methacryloxypropyltrimethoxysilane and the isopropyl di(methacryl) isostearyl titanate is: 1:(0.75-1.25):(0.75-1.25).

[0019] The present invention also provides a method for preparing the ultra-low smoke density cold-resistant halogen-free flame-retardant cable material, comprising the following steps:

[0020] The base resin, inorganic flame retardant, lubricant, reactive smoke suppressant, antioxidant, zinc borate and coupling agent are subjected to banburying to obtain a banburying product, which is then extruded and granulated to obtain the ultra-low smoke density cold-resistant halogen-free flame-retardant cable material.

[0021] Preferably, the banburying temperature is 165-175° C., and the time is 15-20 minutes.

[0022] Preferably, the extrusion temperature is 90-120°C.

[0023] Through the above technical solution, the present invention achieves the following beneficial effects:

[0024] The inorganic flame retardant used in the present invention has the dual effects of flame retardancy and smoke suppression, and the synergistic reactive smoke suppressant makes the smoke density of the cable material ultra-low when it burns; the basic resin, inorganic flame retardant and reactive smoke suppressant used do not contain halogen components and do not produce halogen gas during combustion; through the reasonable ratio of the basic resin, the cable material can withstand low temperatures of -40°C. DETAILED DESCRIPTION

[0025] The following is a detailed description of the specific embodiments of the present invention in conjunction with the examples. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0026] Example 1:

[0027] Preparation of modified aluminum-magnesium hydrotalcite: 100 g of aluminum-magnesium hydrotalcite and 1 g of stearic acid were mixed at 75° C. for 60 min to obtain modified aluminum-magnesium hydrotalcite.

[0028] Preparation of modified magnesium hydroxide: 100 g of magnesium hydroxide was dried at 100° C. for 1 hour, and then 1 g of stearic acid was added and mixed at 100° C. for 30 minutes to obtain modified magnesium hydroxide.

[0029] Preparation of a coupling agent: 0.8 g of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 0.6 g of γ-methacryloxypropyltrimethoxysilane and 0.6 g of isopropyl di(methacryloyl) isostearyl titanate were blended to prepare a coupling agent.

[0030] The following raw materials were weighed: 35 g of ethylene-vinyl acetate copolymer, 5 g of maleic anhydride grafted product, 10 g of metallocene linear polyethylene resin, 40 g of modified aluminum magnesium hydrotalcite, 20 g of modified magnesium hydroxide, 2 g of pentaerythritol stearate, 3 g of melamine cyanurate, 0.5 g of antioxidant 1010, 3 g of zinc borate, and 2 g of coupling agent.

[0031] The above raw materials are mixed and put into an internal mixer for internal mixing. The internal mixing temperature is set to 165°C and the time is 15 minutes. After internal mixing, the product is put into a twin-screw extruder for extrusion. The extruder temperature is set to 90°C. After drying, the ultra-low smoke density, cold-resistant, halogen-free and flame-retardant cable material is obtained.

[0032] Example 2:

[0033] Preparation of modified aluminum-magnesium hydrotalcite: 100 g of aluminum-magnesium hydrotalcite and 1.5 g of stearic acid were mixed at 80° C. for 120 min to obtain modified aluminum-magnesium hydrotalcite.

[0034] Preparation of modified magnesium hydroxide: 100 g of magnesium hydroxide was dried at 110° C. for 1 hour, and then 1.5 g of stearic acid was added and mixed at 105° C. for 30 minutes to obtain modified magnesium hydroxide.

[0035] Preparation of a coupling agent: 0.5 g of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 0.5 g of γ-methacryloxypropyltrimethoxysilane and 0.5 g of isopropyl di(methacryloyl) isostearyl titanate were blended to prepare a coupling agent.

[0036] The following raw materials were weighed: 30 g of ethylene-vinyl acetate copolymer, 10 g of maleic anhydride grafted product, 10 g of metallocene linear polyethylene resin, 40 g of modified aluminum magnesium hydrotalcite, 40 g of modified magnesium hydroxide, 1 g of silicone masterbatch, 2 g of ammonium polyphosphate, 0.2 g of antioxidant DLTP, 2 g of zinc borate, and 1.5 g of coupling agent.

[0037] The above raw materials are mixed and put into an internal mixer for internal mixing. The internal mixing temperature is set to 175°C and the time is 20 minutes. After internal mixing, the product is put into a twin-screw extruder for extrusion. The extruder temperature is set to 105°C. After drying, the ultra-low smoke density, cold-resistant, halogen-free and flame-retardant cable material is obtained.

[0038] Example 3:

[0039] Preparation of modified aluminum-magnesium hydrotalcite: 100 g of aluminum-magnesium hydrotalcite and 1.25 g of stearic acid were mixed at 78° C. for 90 min to obtain modified aluminum-magnesium hydrotalcite.

[0040] Preparation of modified magnesium hydroxide: 100 g of magnesium hydroxide was dried at 105° C. for 1 hour, and then 1.25 g of stearic acid was added and mixed at 102° C. for 30 minutes to obtain modified magnesium hydroxide.

[0041] Preparation of a coupling agent: 0.8 g of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 1 g of γ-methacryloxypropyltrimethoxysilane and 1 g of isopropyl di(methacryl) isostearyl titanate were blended to prepare a coupling agent.

[0042] The following raw materials were weighed: 25 g of ethylene-vinyl acetate copolymer, 5 g of maleic anhydride graft, 20 g of metallocene linear polyethylene resin, 27 g of modified aluminum magnesium hydrotalcite, 18 g of modified magnesium hydroxide, 1.5 g of pentaerythritol stearate, 1.5 g of silicone masterbatch, 2 g of melamine cyanurate, 2 g of ammonium polyphosphate, 0.15 g of antioxidant 1010, 0.2 g of antioxidant DLTP, 5 g of zinc borate, and 1 g of coupling agent.

[0043] The above raw materials are mixed and put into an internal mixer for internal mixing. The internal mixing temperature is set to 170°C and the time is 18 minutes. After internal mixing, the product is put into a twin-screw extruder for extrusion. The extruder temperature is set to 120°C. After drying, the ultra-low smoke density cold-resistant halogen-free flame-retardant cable material is obtained.

[0044] Comparative Example 1:

[0045] This comparative example provides a preparation method of an ultra-low smoke density cold-resistant halogen-free flame-retardant cable material, which differs from Example 1 only in that the modified aluminum-magnesium hydrotalcite in the raw material is replaced by ordinary hydrotalcite.

[0046] Comparative Example 2:

[0047] This comparative example provides a preparation method of an ultra-low smoke density cold-resistant halogen-free flame-retardant cable material, which differs from Example 1 only in that the modified magnesium hydroxide in the raw material is replaced by ordinary magnesium hydroxide.

[0048] Comparative Example 3:

[0049] This comparative example provides a method for preparing an ultra-low smoke density cold-resistant halogen-free flame-retardant cable material, which differs from Example 1 only in that the raw materials do not include modified aluminum-magnesium hydrotalcite and modified magnesium hydroxide.

[0050] Comparative Example 4:

[0051] This comparative example provides a method for preparing an ultra-low smoke density cold-resistant halogen-free flame-retardant cable material, which differs from Example 1 only in that the raw materials do not include ethylene-vinyl acetate copolymer.

[0052] Comparative Example 5:

[0053] This comparative example provides a method for preparing an ultra-low smoke density cold-resistant halogen-free flame-retardant cable material, which differs from Example 1 only in that the raw materials do not include maleic anhydride grafts.

[0054] Comparative Example 6:

[0055] This comparative example provides a method for preparing an ultra-low smoke density cold-resistant halogen-free flame-retardant cable material, which differs from Example 1 only in that the raw materials do not include metallocene linear polyethylene resin.

[0056] The performance of the ultra-low smoke density cold-resistant halogen-free flame-retardant cable materials provided in the above embodiments and comparative examples was tested using the following test methods:

[0057] Density, GB / T 1033.1-2008 Plastics—Determination of density of non-cellular plastics—Part 1: Immersion method, pycnometer method and titration method;

[0058] Tensile strength and elongation, GB / T 1040.3-2006 Plastics - Determination of tensile properties - Part 3: Test conditions for films and sheets;

[0059] Smoke density (flameless) and smoke density (flame), GB / T 8323.2-2008 Plastics smoke generation Part 2: Single chamber method for determination of smoke density test method;

[0060] Oxygen index, GB / T 2406.2-2009 Plastics - Determination of combustion behavior by oxygen index method - Part 2: Room temperature test;

[0061] Low temperature embrittlement, GB / T 5470-2008 Plastics - Determination of brittle temperature by impact method.

[0062] The test results are shown in Table 1.

[0063] Table 1 Properties of ultra-low smoke density cold-resistant halogen-free flame-retardant cable materials obtained in Examples and Comparative Examples

[0064] As shown in Table 1, the cable materials obtained in Comparative Examples 1 and 2, respectively, replaced the modified aluminum-magnesium hydrotalcite and modified magnesium hydroxide with unmodified ordinary aluminum-magnesium hydrotalcite and ordinary magnesium hydroxide. This resulted in smoke densities exceeding 50 in both the flame and flameless conditions, indicating that the cable materials obtained in Comparative Examples 1 and 2 lacked ultra-low smoke properties. Simultaneously, the oxygen index was lower than that of Example 1, demonstrating that modifying the aluminum-magnesium hydrotalcite and magnesium hydroxide can improve the smoke suppression and flame retardancy of the cable material. The cable material obtained in Comparative Example 3, which does not contain both modified aluminum-magnesium hydrotalcite and modified magnesium hydroxide, exhibited a significantly higher smoke density than those in Comparative Examples 1 and 2, while also exhibiting an oxygen index below 30%, indicating that the cable material lacked flame retardancy. However, a comparison of the density, tensile strength, and tensile elongation of Example 1 and Comparative Examples 1 to 3 reveals that the addition of aluminum-magnesium hydrotalcite and magnesium hydroxide to the cable material increased its density and decreased its tensile strength and elongation, whereas the modified materials mitigated this effect to a certain extent, improving the processing and mechanical properties of the cable material. By comparing the data of Example 1 and Comparative Examples 4 to 6, it can be found that the three substances, ethylene-vinyl acetate copolymer, maleic anhydride graft and metallocene linear polyethylene resin, have a positive effect on the tensile strength and tensile elongation of the cable material, especially play a vital role in the resistance to low-temperature embrittlement. Most of the comparative examples 4 to 6 without the addition of these three substances became brittle at -40°C and had no cold resistance.

[0065] As can be seen from the above description, the present invention has the following advantages: the cable material has good mechanical properties, ultra-low smoke resistance and cold resistance, and the material itself does not contain halogen components.

[0066] The preferred embodiments of the present invention are described in detail above in conjunction with the embodiments. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0067] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0068] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. An ultra-low smoke density cold-resistant halogen-free flame-retardant cable material, characterized in that: The invention is prepared from the following raw materials, calculated by weight: 50 parts of base resin, 45-80 parts of inorganic flame retardant, 1-3 parts of lubricant, 2-4 parts of reactive smoke suppressant, 0.2-0.5 parts of antioxidant, 2-5 parts of zinc borate and 1-2 parts of coupling agent; the base resin comprises ethylene-vinyl acetate copolymer, maleic anhydride graft and metallocene linear polyethylene resin in a weight ratio of (25-35):(5-10):(10-20); the inorganic flame retardant is a mixture of modified aluminum-magnesium hydrotalcite and modified magnesium hydroxide.

2. The ultra-low smoke density cold-resistant halogen-free flame-retardant cable material according to claim 1, characterized in that: The mass ratio of the modified aluminum-magnesium hydrotalcite to the modified magnesium hydroxide is (1-2):

1.

3. The ultra-low smoke density cold-resistant halogen-free flame-retardant cable material according to claim 2, characterized in that: The modified aluminum-magnesium hydrotalcite is modified by mixing the aluminum-magnesium hydrotalcite with 1.0-1.5wt% of stearic acid at a mixing temperature of 75-80°C and a mixing time of 60-120 minutes.

4. The ultra-low smoke density cold-resistant halogen-free flame-retardant cable material according to claim 2, characterized in that: The modification method of the modified magnesium hydroxide is as follows: drying the magnesium hydroxide at 100-110° C. for 1 hour, and then mixing it with 1.0-1.5 wt % of stearic acid at a mixing temperature of 100-105° C. for 30 minutes.

5. The ultra-low smoke density cold-resistant halogen-free flame-retardant cable material according to claim 1, characterized in that: The lubricant is pentaerythritol stearate and / or silicone masterbatch; the reactive smoke suppressant is melamine cyanurate and / or ammonium polyphosphate; and the antioxidant is antioxidant 1010 and / or antioxidant DLTP.

6. The ultra-low smoke density cold-resistant halogen-free flame-retardant cable material according to claim 1, characterized in that: The coupling agent is a blend of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and isopropyl di(methacryl) isostearyl titanate.

7. The ultra-low smoke density cold-resistant halogen-free flame-retardant cable material according to claim 6, characterized in that: The mass ratio of the N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, the γ-methacryloxypropyltrimethoxysilane and the isopropyl di(methacryl)isostearyl titanate is: 1:(0.75-1.25):(0.75-1.25).

8. A method for preparing the ultra-low smoke density cold-resistant halogen-free flame-retardant cable material according to any one of claims 1 to 7, characterized in that: The following steps are involved: The base resin, inorganic flame retardant, lubricant, reactive smoke suppressant, antioxidant, zinc borate and coupling agent are subjected to banburying to obtain a banburying product, and the banburying product is then extruded and granulated to obtain the ultra-low smoke density cold-resistant halogen-free flame-retardant cable material.

9. The preparation method according to claim 8, characterized in that: The temperature of the banburying is 165-175°C, and the time is 15-20 minutes; the temperature of the extrusion is 90-120°C.

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