Halogen-free flame-retardant polyolefin cable material and preparation method thereof

Abstract

The invention discloses a halogen-free flame-retardant polyolefin cable material and a preparation method thereof, and belongs to the technical field of cable materials. The halogen-free flame-retardant polyolefin cable material comprises the following raw materials by weight: 40-50 parts of ethylene-vinyl acetate copolymer, 60-70 parts of high-density polyethylene, 15-25 parts of low-density polyethylene, 8-10 parts of flame retardant, 7-9 parts of inorganic filler, 0.8-1 parts of antioxidant, 0.8-1 parts of ultraviolet absorber, 0.5-1 parts of lubricant, 0.5-1 parts of dispersant, and 0.02-0.04 parts of initiator. The halogen-free flame-retardant elements nitrogen, phosphorus, and silicon in the flame retardant are synergistically flame-retardant, and the flame retardant and the inorganic filler act synergistically to jointly give the cable material efficient and safe smoke suppression and flame retardancy; the flame retardant, the inorganic filler, etc. are uniformly dispersed in the matrix material, and have good compatibility with the other raw materials, so that each raw material gives full play to the corresponding role, giving the cable material excellent smoke suppression and flame retardancy, oxidation resistance and toughness.

Description

Technical Field

[0001] The invention belongs to the technical field of cable materials, and in particular relates to a halogen-free flame-retardant polyolefin cable material and a preparation method thereof. Background Art

[0002] With the rapid development of the global economy and the enhancement of people's environmental awareness, various fields have higher and higher requirements for the quality and performance of wires and cables. There are also more and more fires caused by the aging of wires and cables. How to reduce the incidence of fire and the mortality rate when a fire occurs has become the development direction of the wire and cable industry.

[0003] In the early days, people achieved the purpose of flame retardancy by adding a certain amount of halogen-containing flame retardants or using polyvinyl chloride and antimony-based flame retardants during the manufacturing process of wires and cables. However, these cables will release halogens, acid mist and smoke during the combustion process. These substances will cause secondary injuries to people during escape and rescue, and in severe cases will cause suffocation and death. At the same time, the mechanical and electrical properties of the cables will be reduced. Although the existing halogen-free flame-retardant cable materials will not produce toxic and harmful substances when burned, the flame retardants of the existing halogen-free flame-retardant cable materials may be affected by the external environment and migrate out and become ineffective, and more smoke will be emitted when burning, and the flame retardant performance needs to be further improved. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a halogen-free flame-retardant polyolefin cable material and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A halogen-free flame-retardant polyolefin cable material, comprising the following raw materials in parts by weight: 40-50 parts of ethylene-vinyl acetate copolymer, 60-70 parts of high-density polyethylene, 15-25 parts of low-density polyethylene, 8-10 parts of flame retardant, 7-9 parts of inorganic filler, 0.8-1 parts of antioxidant, 0.8-1 parts of ultraviolet absorber, 0.5-1 parts of lubricant, 0.5-1 parts of dispersant, 0.02-0.04 parts of initiator;

[0007] Furthermore, the flame retardant is prepared by the following steps:

[0008] S1. At room temperature, nitrogen was introduced into a dry four-necked flask for 30 minutes to blow away the air in the flask, and then isocyanate propyl triethoxysilane, dimethyl sulfoxide and tributyl tin were added, stirred to dissolve, and then 2,4-diamino-6-diallylamino-1,3,5-triazine was slowly added, and the temperature was raised to 70°C while stirring. After the reaction was kept warm for 3 hours, the reaction was cooled to room temperature after the reaction was completed, and the mixture was distilled under reduced pressure. The whole process was carried out under nitrogen protection to obtain intermediate 1; the amount ratio of isocyanate propyl triethoxysilane, 2,4-diamino-6-diallylamino-1,3,5-triazine, tributyl tin and dimethyl sulfoxide was 12.4mL:10.3g:120mL:0.081g;

[0009] Under the catalytic action of tributyltin, the molar ratio of isocyanatepropyltriethoxysilane and 2,4-diamino-6-diallylamino-1,3,5-triazine is controlled to be 1:1, and the isocyanate group of isocyanatepropyltriethoxysilane and the amino group of 2,4-diamino-6-diallylamino-1,3,5-triazine undergo nucleophilic addition reaction to generate intermediate 1. The reaction process is shown below:

[0010]

[0011] S2. At room temperature, nitrogen was introduced into a dry four-necked flask for 30 minutes to blow out the air in the flask, and then intermediate 1, dodecanol, N,N-dimethylformamide (DMF) and tetraisopropyl titanate were added, stirred and dissolved, and then the temperature was raised to 100°C and reacted for 36 hours. After the reaction was completed, it was cooled to room temperature and distilled under reduced pressure. The whole process was carried out under nitrogen protection to obtain intermediate 2; the amount ratio of intermediate 1, dodecanol, DMF and tetraisopropyl titanate was 13.6g:6.7mL:130mL:0.043g;

[0012] Under the catalytic action of tetraisopropyl titanate, the molar ratio of intermediate 1 to dodecanol is controlled to be 1:1, and the silicon ethoxy group of intermediate 1 and the hydroxyl group of dodecanol undergo the following chemical reaction to generate intermediate 2. The reaction process is as follows:

[0013]

[0014] S3, nitrogen was introduced into a dry brown four-necked flask at room temperature for 30 minutes to blow out the air in the flask, then di-n-butyl chlorophosphate, triethylamine, and toluene were added, and the mixture was stirred until uniformly mixed, and then 3-chloro-1-propanol was slowly added, and the reaction was stirred at room temperature for 3 hours. After the reaction was completed, the reaction was distilled under reduced pressure. The whole process was carried out under nitrogen protection to obtain intermediate 3; the amount ratio of di-n-butyl chlorophosphate, 3-chloro-1-propanol, triethylamine and toluene was 11.4 g:4.2 mL:7 mL:110 mL;

[0015] Di-n-butyl chlorophosphate and 3-chloro-1-propanol can undergo the following chemical reaction under the action of triethylamine to generate intermediate 3. The reaction process is shown below:

[0016]

[0017] S4. At room temperature, nitrogen was introduced into a dry brown four-necked flask for 30 minutes to blow out the air in the flask, and then intermediate 2, intermediate 3, triethylamine and DMF were added, stirred to dissolve, and then the temperature was raised to 90°C and kept for reaction for 5 hours. After the reaction was completed, it was cooled to room temperature, distilled under reduced pressure, washed with anhydrous ethanol 5 times, and rotary evaporated. The whole process was carried out under nitrogen protection to obtain a flame retardant; intermediate 2, intermediate 3, triethylamine and DMF 11.9g:5.7g:3mL:120mL.

[0018] The -NH2 of intermediate 2 and the -Cl of intermediate 3 undergo a one-molecule nucleophilic substitution reaction, and triethylamine removes the hydrogen chloride generated by the reaction to obtain a flame retardant. The reaction process is as follows:

[0019]

[0020] The flame retardant of the present invention is a synergistic flame retardant of nitrogen, phosphorus and silicon. When the substrate burns, the flame retardant in the substrate will decompose to produce dehydrating agents such as phosphoric acid and metaphosphoric acid to promote carbonization of the substrate. Under the action of nitrogen, the molten carbon layer formed on the surface of the substrate will expand and foam to form a porous foam structure, and a large amount of expanded porous foam carbon layer will play a role in blocking the flow of combustible gas and heat, thereby preventing the substrate material from burning. At the same time, a large amount of non-combustible gases such as carbon dioxide, nitrogen dioxide, water vapor and ammonia will be released to further prevent the substrate material from burning; the silane alkoxy on the flame retardant will hydrolyze and condense, and then produce a chemical reaction with the inorganic filler to promote the inorganic filler and the flame retardant The flame retardant of the present invention contains a long carbon chain that can freely expand, contract and rotate, and the long carbon chain is interspersed between the macromolecular chains of the matrix resin, which has a toughening effect and also increases the compatibility of the flame retardant with the other raw materials. The presence of phosphate groups, amino groups, amide groups, etc. further increases the compatibility between the flame retardant and the raw materials. In addition, the multiple terminal carbon-carbon double bonds on the flame retardant can react chemically with the unreacted carbon-carbon double bonds at the end of the matrix resin under the action of the initiator. Therefore, the flame retardant of the present invention can be highly dispersed and stably present in the cable material, is not easy to migrate out, and exerts a flame retardant and smoke suppression effect for a long time.

[0021] Furthermore, the inorganic filler is one or more of aluminum hydroxide, magnesium hydroxide, and zinc oxide.

[0022] Furthermore, the antioxidant is one or more of antioxidant 1010, antioxidant CA, antioxidant 1076 and antioxidant 168.

[0023] Furthermore, the ultraviolet absorber is one or more of 2-hydroxy-4-octyloxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole, and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine.

[0024] Furthermore, the lubricant is one or more of polyethylene wax, calcium stearate, and magnesium stearate.

[0025] Furthermore, the dispersant is zinc stearate.

[0026] Furthermore, the initiator is tert-butyl perbenzoate.

[0027] A method for preparing a halogen-free flame-retardant polyolefin cable material comprises the following steps:

[0028] Ethylene-vinyl acetate copolymer, high-density polyethylene and low-density polyethylene are mixed uniformly in proportion and then banburying is performed to obtain a mixture; then flame retardants, inorganic fillers, dispersants, initiators, antioxidants, ultraviolet absorbers and lubricants are added to the mixture, mixed uniformly and then banburying is performed again to obtain a banburying mixture; finally, the banburying mixture is extruded, pelletized, granulated, cooled and screened to obtain a halogen-free flame-retardant polyolefin cable material.

[0029] The beneficial effects of the present invention are as follows: the halogen-free flame retardant elements nitrogen, phosphorus and silicon in the flame retardant are synergistic flame retardant, and the flame retardant and the inorganic filler act synergistically to give the cable material efficient and safe smoke suppression and flame retardancy; the flame retardant, inorganic filler, etc. are evenly dispersed in the matrix material and have good compatibility with the other raw materials, so that each raw material fully exerts its corresponding role, giving the cable material excellent smoke suppression and flame retardancy, oxidation resistance and toughness, etc. DETAILED DESCRIPTION

[0030] 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 creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] The flame retardant is prepared in the following steps:

[0033] S1. At room temperature, nitrogen was introduced into a dry 250 mL four-necked flask for 30 minutes to blow out the air in the flask, and then 12.4 mL of isocyanatepropyltriethoxysilane, 120 mL of dimethyl sulfoxide and 0.081 g of tributyltin were added, stirred to dissolve, and then 10.3 g of 2,4-diamino-6-diallylamino-1,3,5-triazine was slowly added, and the temperature was raised to 70°C while stirring. After the reaction was kept warm for 3 hours, the reaction was cooled to room temperature after the reaction was completed, and the intermediate 1 was obtained by distillation under reduced pressure. The whole process was carried out under nitrogen protection to obtain the intermediate 1.

[0034] S2. At room temperature, nitrogen was introduced into a dry 250 mL four-necked flask for 30 minutes to blow out the air in the flask, and then 13.6 g of intermediate 1, 6.7 mL of dodecanol, 130 mL of DMF and 0.043 g of tetraisopropyl titanate were added, stirred and dissolved, and then the temperature was raised to 100 ° C. and reacted for 36 hours. After the reaction was completed, it was cooled to room temperature and distilled under reduced pressure. The whole process was carried out under nitrogen protection to obtain intermediate 2;

[0035] S3, nitrogen was introduced into a dry 250 mL brown four-necked flask at room temperature for 30 minutes to blow out the air in the flask, then 11.4 g of di-n-butyl chlorophosphate, 7 mL of triethylamine, and 110 mL of toluene were added, and the mixture was stirred until uniformly mixed, and then 4.2 mL of 3-chloro-1-propanol was slowly added, and the reaction was stirred at room temperature for 3 h. After the reaction was completed, the mixture was distilled under reduced pressure. The whole process was carried out under nitrogen protection to obtain intermediate 3;

[0036] S4. At room temperature, nitrogen was passed into a dry brown four-necked flask for 30 minutes to blow out the air in the flask, and then 11.9 g of intermediate 2, 5.7 g of intermediate 3, 3 mL of triethylamine and 120 mL of DMF were added, stirred to dissolve, and then the temperature was raised to 90°C and kept for reaction for 5 hours. After the reaction was completed, it was cooled to room temperature, distilled under reduced pressure, washed with anhydrous ethanol 5 times, and rotary evaporated. The whole process was carried out under nitrogen protection to obtain a flame retardant.

[0037] Example 2

[0038] The specific steps for preparing cable materials are as follows:

[0039] 40 parts of ethylene-vinyl acetate copolymer, 60 parts of high-density polyethylene and 15 parts of low-density polyethylene were mixed uniformly and then banburying was performed to obtain a mixture; then 8 parts of the flame retardant of Example 1, 7 parts of magnesium hydroxide, 0.5 parts of zinc stearate, 0.02 parts of tert-butyl perbenzoate, 0.5 parts of antioxidant 1010, 0.3 parts of antioxidant 168, 0.8 parts of 2-hydroxy-4-n-octyloxybenzophenone and 0.5 parts of polyethylene wax were added to the mixture, mixed uniformly and then banburying was performed again to obtain a banburying mixture; finally, the banburying mixture was extruded, pelletized, granulated, cooled and screened to obtain a cable material.

[0040] Example 3

[0041] The specific steps for preparing cable materials are as follows:

[0042] 45 parts of ethylene-vinyl acetate copolymer, 66 parts of high-density polyethylene and 20 parts of low-density polyethylene are mixed evenly and then banburying is performed to obtain a mixture; then 9 parts of the flame retardant of Example 1, 4 parts of aluminum hydroxide, 4 parts of magnesium hydroxide, 0.7 parts of zinc stearate, 0.03 parts of tert-butyl perbenzoate, 0.9 parts of antioxidant CA, 0.9 parts of 2-(2'-hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole and 0.8 parts of calcium stearate are added to the mixture, mixed evenly and then banburying is performed again to obtain a banburying mixture; finally, the banburying mixture is extruded, pelletized, granulated, cooled and screened to obtain a cable material.

[0043] Example 4

[0044] The specific steps for preparing cable materials are as follows:

[0045] 50 parts of ethylene-vinyl acetate copolymer, 70 parts of high-density polyethylene and 25 parts of low-density polyethylene are mixed uniformly and then banburying is performed to obtain a mixture; then 10 parts of the flame retardant of Example 1, 4 parts of zinc oxide, 5 parts of magnesium hydroxide, 1 part of zinc stearate, 0.04 parts of tert-butyl perbenzoate, 0.4 parts of antioxidant 1076, 0.6 parts of antioxidant 168, 1 part of 4-benzoyloxy-2,2,6,6-tetramethylpiperidine and 1 part of magnesium stearate are added to the mixture, mixed uniformly and then banburying is performed again to obtain a banburying mixture; finally, the banburying mixture is extruded, pelletized, granulated, cooled and screened to obtain a cable material.

[0046] Comparative Example 1

[0047] The specific steps for preparing cable materials are as follows:

[0048] The remaining steps remain unchanged, and the flame retardant in Example 4 is removed to prepare the cable material.

[0049] Comparative Example 2

[0050] The specific steps for preparing cable materials are as follows:

[0051] The remaining steps remain unchanged, and the flame retardant in Example 4 is replaced by the flame retardant Doher-737 produced by Dongguan Doher New Material Technology Co., Ltd. to prepare the cable material.

[0052] Performance Testing

[0053] The cable materials prepared in Examples 2-4 and Comparative Examples 1-2 were subjected to the following performance tests:

[0054] Limiting Oxygen Index (LOI): LOI test is carried out in accordance with GB / T2406, sample size is 130×6.5×3mm 3 ;

[0055] Vertical combustion test (UL-94): UL-94 test refers to GB / T2408-2008, the sheath material sample size is 100×13×3mm 3 According to the duration of the flame of the sample, the UL-94 grade is divided into V-0, V-1, V-2 and no grade (indicated by "-"); the test results are shown in Table 1 below:

[0056] Table 1

[0057]

[0058] It can be seen from the test results in Table 1 above that the cable material prepared in the embodiment of the present invention has excellent flame retardant properties.

[0059] The cable materials prepared in Examples 2-4 and Comparative Examples 1-2 were also subjected to the following performance tests, and the test results are shown in Table 2 below:

[0060] Table 2

[0061]

[0062] It can be seen from the test results in Table 2 above that the cable material prepared in the embodiment of the present invention also has excellent mechanical properties and anti-aging properties.

[0063] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0064] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways. As long as they do not deviate from the scope defined by the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A halogen-free flame-retardant polyolefin cable material, characterized in that: The invention comprises the following raw materials in parts by weight: 40-50 parts of ethylene-vinyl acetate copolymer, 60-70 parts of high-density polyethylene, 15-25 parts of low-density polyethylene, 8-10 parts of flame retardant, 7-9 parts of inorganic filler, 0.8-1 parts of antioxidant, 0.8-1 parts of ultraviolet absorber, 0.5-1 parts of lubricant, 0.5-1 parts of dispersant, and 0.02-0.04 parts of initiator; Wherein, the flame retardant is prepared by the following steps: S1. Pass nitrogen into the flask, add isocyanatepropyltriethoxysilane, dimethyl sulfoxide and tributyltin, stir, then add 2,4-diamino-6-diallylamino-1,3,5-triazine, heat to 70°C for 3h, cool, and distill under reduced pressure to obtain intermediate 1; S2, nitrogen was passed into the flask, and intermediate 1, dodecanol, DMF and tetraisopropyl titanate were added, stirred, heated to 100°C for reaction for 36 hours, cooled, and distilled under reduced pressure to obtain intermediate 2; S3, nitrogen was passed into the flask, di-n-butyl chlorophosphate, triethylamine, and toluene were added, 3-chloro-1-propanol was added after stirring, the reaction was carried out at room temperature for 3 hours, and distillation was carried out under reduced pressure to obtain intermediate 3; S4, pass nitrogen into the flask, add intermediate 2, intermediate 3, triethylamine and DMF, stir, heat to 90°C to react for 5h, cool, distill under reduced pressure, wash, and rotary evaporate to obtain a flame retardant; The amount ratio of isocyanatepropyltriethoxysilane, 2,4-diamino-6-diallylamino-1,3,5-triazine, tributyltin and dimethyl sulfoxide in step S1 is 12.4mL:10.3g:120mL:0.081g; the amount ratio of intermediate 1, dodecanol, DMF and tetraisopropyl titanate in step S2 is 13.6g:6.7mL:130mL:0.043g; the amount ratio of di-n-butyl chlorophosphate, 3-chloro-1-propanol, triethylamine and toluene in step S3 is 11.4g:4.2mL:7mL:110mL; the amount ratio of intermediate 2, intermediate 3, triethylamine and DMF in step S4 is 11.9g:5.7g:3mL:120mL.

2. The halogen-free flame-retardant polyolefin cable material according to claim 1, characterized in that: The inorganic filler is one or more of aluminum hydroxide, magnesium hydroxide and zinc oxide.

3. The halogen-free flame-retardant polyolefin cable material according to claim 1, characterized in that: The antioxidant is one or more of antioxidant 1010, antioxidant CA, antioxidant 1076 and antioxidant 168.

4. The halogen-free flame-retardant polyolefin cable material according to claim 1, characterized in that: The ultraviolet absorber is one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole, and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine.

5. The halogen-free flame-retardant polyolefin cable material according to claim 1, characterized in that: The lubricant is one or more of polyethylene wax, calcium stearate and magnesium stearate.

6. The halogen-free flame-retardant polyolefin cable material according to claim 1, characterized in that: The dispersant is zinc stearate.

7. The halogen-free flame-retardant polyolefin cable material according to claim 1, characterized in that: The initiator is tert-butyl perbenzoate.

8. The method for preparing a halogen-free flame-retardant polyolefin cable material according to claim 1, characterized in that: The following steps are involved: Ethylene-vinyl acetate copolymer, high-density polyethylene and low-density polyethylene are mixed uniformly in proportion and then banburying is performed to obtain a mixture; then flame retardants, inorganic fillers, dispersants, initiators, antioxidants, ultraviolet absorbers and lubricants are added to the mixture, mixed uniformly and then banburying is performed again to obtain a banburying mixture; finally, the banburying mixture is extruded, pelletized, granulated, cooled and screened to obtain a halogen-free flame-retardant polyolefin cable material.

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