A weather-resistant and flame-retardant PVC cable material for charging piles

Abstract

The present invention discloses a weather-resistant flame-retardant PVC cable material for charging piles, which belongs to the field of cable technology and includes the following raw materials by weight: 100 parts of PVC resin, 45-55 parts of plasticizer, 8-12 parts of flame retardant, 4-6 parts of calcium / zinc composite stabilizer, 30-40 parts of calcined clay, and 1-1.2 parts of lubricant. The present invention uses a compound of DOTP and DOP as a main plasticizer, which can not only play a good toughening effect, but also improve the weather resistance of PVC cable materials; synthesize new flame retardants by chemical means to be applied to PVC cable materials, which can not only significantly improve the flame retardant properties of cable materials, but also improve the anti-aging properties of PVC cable materials, thereby improving its weather resistance; it can also synergize with the main plasticizer to make the PVC cable material have good toughness; finally obtain a PVC cable material with both weather resistance and flame retardancy, which can be applied to the cable structure of charging piles.

Description

Technical Field

[0001] The present invention belongs to the technical field of cables, and in particular, relates to a weather-resistant and flame-retardant PVC cable material for a charging pile. Background Art

[0002] Polyvinyl chloride (PVC) is a general-purpose plastic with the advantages of low cost, easy processing, excellent mechanical properties, corrosion resistance and excellent insulation. It is widely used in the fields of construction, light industry, chemical industry, electrical appliances, wires and cables, etc. Among them, in the field of wires and cables, PVC is usually used as the outer coating material of the cable. PVC cable material is based on polyvinyl chloride resin, with stabilizers, plasticizers, inorganic fillers such as calcium carbonate, additives and lubricants, etc. added, and the particles are prepared by mixing, kneading and extrusion.

[0003] PVC itself is a hard material with an oxygen index of 45 (flame retardant), but when it is used as a cable material, a large amount of plasticizer needs to be added to the polyvinyl chloride resin to achieve the purpose of softness and low temperature resistance. However, the addition of plasticizers will cause the oxygen index of polyvinyl chloride materials to drop significantly. When such PVC materials are used in charging piles, considering the high requirements of charging piles for the flame retardant and fireproof properties of cables, it is necessary to improve the flame retardant and fireproof properties of PVC materials; in addition, most of the existing public charging piles are set up under outdoor conditions, and the weather resistance requirements for cables are also high. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a weather-resistant and flame-retardant PVC cable material for a charging pile.

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

[0006] A weather-resistant flame-retardant PVC cable material for a charging pile, comprising the following raw materials by weight: 100 parts of PVC resin, 45-55 parts of plasticizer, 8-12 parts of flame retardant, 4-6 parts of calcium / zinc composite stabilizer, 30-40 parts of calcined clay, and 1-1.2 parts of lubricant;

[0007] The preparation method of the above PVC cable material comprises the following steps:

[0008] Put PVC resin, plasticizer, flame retardant, calcium / zinc composite stabilizer and lubricant into a mixer, mix and stir evenly at 100-110°C, then add calcined clay, mix and stir evenly at 70-80°C to obtain a mixture;

[0009] The mixed material is fed into a twin-screw extruder and extruded and granulated at 150-160° C. to obtain the PVC cable material.

[0010] Furthermore, the plasticizer is a compound of DOTP (dioctyl terephthalate) and DOP (dioctyl phthalate) in a mass ratio of 3-4:2; DOTP has better cold resistance, heat stability and electrical insulation than DOP (about 18 times higher than DOP); therefore, the use of DOP and DOTP plasticizers can improve the weather resistance of PVC cable materials.

[0011] Furthermore, the lubricant is stearic acid or paraffin.

[0012] Furthermore, the flame retardant is prepared by the following steps:

[0013] S1. In a three-necked flask equipped with a stirrer, a thermometer and a condenser, nitrogen is continuously introduced for 10 minutes (to replace the air in the flask), hexachlorocyclotriphosphazene, dioxane and N,N-dimethylaniline are added, stirred and dissolved evenly, and then a dioxane solution of 2-hydroxymethyl-1,3-propanediol is added dropwise. During the addition, the reaction temperature is controlled not to be higher than 40°C. After the addition is completed, the temperature is raised to 100°C, and the reaction is kept warm for 15 hours, and then the temperature is lowered to below 30°C. The generated N,N-dimethylaniline hydrochloride is removed by suction filtration, and the dioxane is removed by distillation under reduced pressure from the filtrate. The filtrate is washed twice with distilled water, and the lower organic phase is separated. Then ethyl acetate is added, and the mixture is dried with anhydrous sodium sulfate and filtered. The ethyl acetate is removed by distillation under reduced pressure from the filtrate to obtain intermediate 1; the ratio of hexachlorocyclotriphosphazene, N,N-dimethylaniline and 2-hydroxymethyl-1,3-propanediol is 10.4g:21.8g:9.6g;

[0014] Hexachlorocyclotriphosphazene undergoes substitution and cyclization reaction with 2-hydroxymethyl-1,3-propanediol to obtain intermediate 1. The process is as follows:

[0015]

[0016] S2. In a three-necked flask, acetonitrile, intermediate 1, N-hydroxyphthalimide and copper oxide were added in sequence, and then oxygen (oxygen flow rate 20 mL / min) was introduced under normal pressure, heated, and stirred at a constant temperature of 70°C for 12 hours. After the reaction was completed, acetonitrile was removed by vacuum distillation, deionized water was added and mixed, and then extracted with ethyl acetate. The organic phase was taken, dried with anhydrous sodium sulfate, filtered, and the filtrate was subjected to rotary evaporation to obtain intermediate 2; the ratio of the amount of intermediate 1, N-hydroxyphthalimide and copper oxide was 13.4 g:0.98 g:1.1 g;

[0017] Under the action of N-hydroxyphthalimide and copper oxide, the primary alcohol on the intermediate 1 molecule is oxidized to form a carboxylic acid to obtain intermediate 2. The reaction process is as follows:

[0018]

[0019] S3, DIC (N,N-diisopropylcarbodiimide), intermediate 2, ether and ethyl acetate were added to a three-necked flask with a stirring device, nitrogen was introduced for protection, and after stirring and dissolving uniformly, tetramethylpiperidinamine and triethylamine were added to the system, and the mixture was heated to room temperature and N 2 The reaction was stirred for 3 hours under protection. After the reaction was completed, the solvent (ether and ethyl acetate) was removed by vacuum distillation. Deionized water was added to the product, mixed evenly, and then extracted with ethyl acetate. The organic layer was taken, dried over anhydrous magnesium sulfate, filtered, and the filtrate was subjected to vacuum rotary distillation to remove ethyl acetate to obtain intermediate 3; the dosage ratio of DIC, intermediate 2, tetramethylpiperidinamine, and triethylamine was 11.9 g: 14.7 g: 14.1 g: 9.1 g;

[0020] Under the action of DIC and triethylamine, the -COOH on the intermediate 2 molecule reacts with the -NH on the tetramethylpiperidinamine molecule. 2 An amidation reaction occurs, and the molar ratio of the two is controlled to be 1:3 to obtain intermediate 3. The reaction process is as follows:

[0021]

[0022] S4, use N 2 The air in the four-necked flask was removed, and octadecane chloride was added, and the mixture was placed in an ice-water bath. A mixed solution of ethyl acetate containing intermediate 3 and triethylamine was slowly added dropwise under stirring. After the addition was completed, the mixture was heated to 40°C and reacted for 4 hours. The triethylamine hydrochloride was removed by suction filtration, and the filtrate was subjected to reduced pressure distillation to obtain a flame retardant. The ratio of octadecane chloride, intermediate 3 and triethylamine was 26g:27.1g:9.1g.

[0023] The -Cl on the chlorooctadecane molecule undergoes a nucleophilic substitution reaction with the -NH- on the intermediate 3. By controlling the molar ratio of the two to 3:1, a flame retardant is obtained. The reaction process is as follows:

[0024]

[0025] The flame retardant obtained has a phosphazene six-membered ring as the center, and a phosphate ring as the periphery of the phosphazene six-membered ring. Therefore, the flame retardant contains a PN synergistic flame retardant component, has a gas phase and condensed phase flame retardant mechanism, and the flame retardant component is a stable four-ring structure, which makes the flame retardant have good thermal stability; in addition, the flame retardant molecule also contains multiple hindered amine structures, which achieve the purpose of light stabilization of the polymer by capturing free radicals generated during the photooxidation and degradation of the polymer, decomposing alkyl hydroperoxide, quenching excited state energy and other methods, thereby making the flame retardant have a good light aging effect;

[0026] It should be further explained that the flame retardant molecules also contain long aliphatic carbon chains (C18 long chains) distributed in a dendrite-like manner, which not only have good compatibility with the PVC matrix, thereby promoting the uniform dispersion of the flame retardant in the PVC cable material, but also have extremely high flexibility, which can penetrate between the macromolecular chains of PVC, weaken the interaction between the PVC molecular chains, and reduce the entanglement between the PVC molecular chains, thereby playing an auxiliary toughening effect, and synergizing with the main plasticizer to make the PVC cable material have good toughness;

[0027] The flame retardant evenly dispersed in the PVC cable material can not only significantly improve the flame retardant properties of the cable material, but also improve the anti-aging properties of the PVC cable material, thereby improving its weather resistance; it can also synergize with the main plasticizer to make the PVC cable material have good toughness; in addition, compared with ordinary organic phosphorus and nitrogen flame retardants, the flame retardant molecules have a higher molecular weight and a more stable multi-ring structure. Therefore, they can exist more stably in the cable material, improving the long-term stability of the flame retardant and anti-aging effects.

[0028] Beneficial effects of the present invention:

[0029] The present invention uses a compound of DOTP and DOP as a main plasticizer, which not only has a good toughening effect, but also can improve the weather resistance of PVC cable materials; a new flame retardant is synthesized by chemical means and applied to PVC cable materials, which can not only significantly improve the flame retardant properties of the cable materials, but also improve the anti-aging properties of the PVC cable materials, thereby improving its weather resistance; it can also synergize with the main plasticizer to make the PVC cable materials have good toughness; in addition, compared with ordinary organic phosphorus nitrogen flame retardants, the flame retardant molecules have a higher molecular weight and a more stable multi-ring structure, therefore, they can exist more stably in the cable materials, and improve the long-term stability of the flame retardant and anti-aging effects; finally, a PVC cable material with both weather resistance and flame retardancy is obtained, which can be applied to the cable structure of charging piles. 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] Preparation of flame retardant:

[0033] S1. In a three-necked flask equipped with a stirrer, a thermometer and a condenser, nitrogen was continuously introduced for 10 minutes (to replace the air in the flask), and then 10.4 g of hexachlorocyclotriphosphazene, 120 mL of dioxane and 21.8 g of N, N-dimethylaniline were added, stirred and dissolved evenly, and then 30 mL of dioxane solution containing 9.6 g of 2-hydroxymethyl-1,3-propanediol was added dropwise. The reaction temperature was controlled not to be higher than 40°C during the addition process. After the addition was completed, the temperature was raised to 100°C, and the reaction was kept warm for 15 hours, and then the temperature was lowered to below 30°C. The generated N, N-dimethylaniline hydrochloride was removed by suction filtration, and the dioxane was removed by distillation under reduced pressure from the filtrate. The filtrate was washed twice with distilled water, and the lower organic phase was separated. Then ethyl acetate was added, and the mixture was dried with anhydrous sodium sulfate and filtered. The filtrate was distilled under reduced pressure to remove ethyl acetate to obtain intermediate 1;

[0034] S2, in a three-necked flask, 100 mL of acetonitrile, 13.4 g of intermediate 1, 0.98 g of N-hydroxyphthalimide and 1.1 g of copper oxide were added in sequence, and then oxygen was introduced under normal pressure (oxygen flow rate 20 mL / min), heated, and stirred at a constant temperature of 70°C for 12 h. After the reaction was completed, acetonitrile was removed by vacuum distillation, deionized water was added and mixed, and then extracted with ethyl acetate, the organic phase was taken, anhydrous sodium sulfate was added and dried, and then filtered, and the filtrate was subjected to rotary evaporation to obtain intermediate 2;

[0035] S3, 11.9 g of DIC, 14.7 g of intermediate 2, 40 mL of ether and 120 mL of ethyl acetate were added to a three-necked flask with a stirring device, nitrogen was introduced for protection, and after stirring and dissolving evenly, 14.1 g of tetramethylpiperidinamine and 9.1 g of triethylamine were added to the system, and the mixture was stirred at room temperature and N 2 The reaction was stirred for 3 h under protection. After the reaction was completed, the solvent (ether and ethyl acetate) was removed by vacuum distillation. Deionized water was added to the product and mixed evenly. The product was extracted with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate and filtered. The filtrate was subjected to vacuum rotary distillation to remove ethyl acetate to obtain intermediate 3.

[0036] S4, use N 2 The air in the four-necked flask was removed, and 26 g of octadecane chloride was added. The flask was placed in an ice-water bath, and 60 mL of a mixture of 27.1 g of intermediate 3 and 9.1 g of triethylamine in ethyl acetate was slowly dropped into the flask under stirring. After the addition was completed, the temperature was raised to 40 °C and the reaction was carried out for 4 h. The triethylamine hydrochloride was removed by suction, and the filtrate was distilled under reduced pressure to obtain a flame retardant.

[0037] Example 2

[0038] Preparation of flame retardant:

[0039] S1. In a three-necked flask equipped with a stirrer, a thermometer and a condenser, nitrogen was continuously introduced for 10 minutes (to replace the air in the flask), and then 20.8 g of hexachlorocyclotriphosphazene, 240 mL of dioxane and 43.6 g of N, N-dimethylaniline were added, and the mixture was stirred and dissolved evenly. Then, 50 mL of a dioxane solution containing 19.2 g of 2-hydroxymethyl-1, 3-propanediol was added dropwise. During the addition, the reaction temperature was controlled not to be higher than 40°C. After the addition was completed, the temperature was raised to 100°C, and the reaction was kept warm for 15 hours, and then the temperature was lowered to below 30°C. The generated N, N-dimethylaniline hydrochloride was removed by suction filtration, and the dioxane was removed by distillation under reduced pressure from the filtrate. The filtrate was washed twice with distilled water, and the lower organic phase was separated. Then, ethyl acetate was added, and the mixture was dried with anhydrous sodium sulfate and filtered. The filtrate was distilled under reduced pressure to remove ethyl acetate to obtain intermediate 1.

[0040] S2, in a three-necked flask, 180 mL of acetonitrile, 26.8 g of intermediate 1, 1.96 g of N-hydroxyphthalimide and 2.2 g of copper oxide were added in sequence, and then oxygen was introduced under normal pressure (oxygen flow rate 20 mL / min), heated, and stirred at a constant temperature of 70°C for 12 h. After the reaction was completed, acetonitrile was removed by vacuum distillation, deionized water was added and mixed, and then extracted with ethyl acetate, the organic phase was taken, anhydrous sodium sulfate was added and dried, and then filtered. The filtrate was subjected to rotary evaporation to obtain intermediate 2;

[0041] S3, 23.8g of DIC, 29.4g of intermediate 2, 80mL of ether and 250mL of ethyl acetate were added to a three-necked flask with a stirring device, nitrogen was introduced for protection, and after stirring and dissolving evenly, 28.2g of tetramethylpiperidinamine and 18.2g of triethylamine were added to the system, and the mixture was stirred at room temperature and N 2 The reaction was stirred for 3 h under protection. After the reaction was completed, the solvent (ether and ethyl acetate) was removed by vacuum distillation. Deionized water was added to the product and mixed evenly. The product was extracted with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate and filtered. The filtrate was subjected to vacuum rotary distillation to remove ethyl acetate to obtain intermediate 3.

[0042] S4, use N 2 The air in the four-necked flask was removed, and 52 g of octadecane chloride was added. The flask was placed in an ice-water bath, and 100 mL of a mixture of 54.2 g of intermediate 3 and 18.2 g of triethylamine in ethyl acetate was slowly dropped in with stirring. After the addition was completed, the temperature was raised to 40°C and the reaction was carried out for 4 hours. The triethylamine hydrochloride was removed by suction, and the filtrate was distilled under reduced pressure to obtain a flame retardant.

[0043] Example 3

[0044] Preparation of weather-resistant and flame-retardant PVC cable materials for charging piles:

[0045] 750 g of DOTP and 500 g of DOP were mixed to obtain a plasticizer;

[0046] 1 kg of PVC resin, 450 g of plasticizer, 80 g of the flame retardant prepared in Example 1, 40 g of calcium / zinc composite stabilizer and 10 g of stearic acid were put into a mixer, mixed and stirred evenly at 100 ° C, and then 300 g of calcined clay was added, mixed and stirred evenly at 70 ° C to obtain a mixture;

[0047] The mixed material is fed into a twin-screw extruder and extruded and granulated at 150° C. to obtain the PVC cable material.

[0048] Example 4

[0049] Preparation of weather-resistant and flame-retardant PVC cable materials for charging piles:

[0050] 875 g of DOTP and 500 g of DOP were mixed to obtain a plasticizer;

[0051] 1 kg of PVC resin, 500 g of plasticizer, 100 g of the flame retardant prepared in Example 2, 50 g of calcium / zinc composite stabilizer and 11 g of stearic acid were put into a mixer, mixed and stirred evenly at 105° C., then 350 g of calcined clay was added, and mixed and stirred evenly at 75° C. to obtain a mixture;

[0052] The mixed material is fed into a twin-screw extruder and extruded and granulated at 155° C. to obtain the PVC cable material.

[0053] Example 5

[0054] Preparation of weather-resistant and flame-retardant PVC cable materials for charging piles:

[0055] 1000 g of DOTP and 500 g of DOP were mixed to obtain a plasticizer;

[0056] 1 kg of PVC resin, 550 g of plasticizer, 120 g of the flame retardant prepared in Example 1, 60 g of calcium / zinc composite stabilizer and 12 g of paraffin were put into a mixer, mixed and stirred evenly at 110° C., then 400 g of calcined clay was added, and mixed and stirred evenly at 80° C. to obtain a mixture;

[0057] The mixed material is fed into a twin-screw extruder and extruded and granulated at 160° C. to obtain the PVC cable material.

[0058] The PVC cable materials obtained in Examples 5-7 were processed and cut into test samples, and the following performance tests were performed:

[0059] 1) Test mechanical properties according to GB / T 8815-2002;

[0060] 2) After 720 hours of sunlight irradiation, test the mechanical property retention rate;

[0061] 3) Conduct limiting oxygen index test according to GB / T 2406.2-2009 "Determination of combustion behavior of plastics by oxygen index method Part 2 Room temperature test";

[0062] 4) Test the flame retardancy of the film according to UL 94 standard;

[0063] The measured results are shown in the following table:

[0064]

[0065] It can be seen from the data in the above table that the cable material obtained by the present invention has higher weather resistance and flame retardancy, and has higher mechanical strength.

[0066] 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.

[0067] 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 a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A weather-resistant and flame-retardant PVC cable material for a charging pile, characterized in that: The raw materials include the following in parts by weight: 100 parts of PVC resin, 45-55 parts of plasticizer, 8-12 parts of flame retardant, 4-6 parts of calcium / zinc composite stabilizer, 30-40 parts of calcined clay, and 1-1.2 parts of lubricant; Wherein, the flame retardant is prepared by the following steps: S1. After nitrogen is continuously introduced into a three-necked flask for 10 minutes, hexachlorocyclotriphosphazene, dioxane and N,N-dimethylaniline are added, stirred and dissolved evenly, and then a dioxane solution of 2-hydroxymethyl-1,3-propanediol is added dropwise. During the addition, the reaction temperature is controlled not to be higher than 40°C. After the addition is completed, the temperature is raised to 100°C, and the temperature is kept for reaction for 15 hours, and then the temperature is lowered to below 30°C, and post-treated to obtain intermediate 1; S2. Add acetonitrile, intermediate 1, N-hydroxyphthalimide and copper oxide in a three-necked flask in sequence, then introduce oxygen under normal pressure, heat, and react at 70°C with constant temperature stirring for 12 hours. After the reaction is completed, remove acetonitrile by vacuum distillation, add deionized water and mix, then extract with ethyl acetate, take the organic phase, add anhydrous sodium sulfate to dry, filter, and rotary evaporate the filtrate to obtain intermediate 2; S3, DIC, intermediate 2, ether and ethyl acetate were added to a three-necked flask, nitrogen was introduced for protection, and after stirring and dissolving evenly, tetramethylpiperidinamine and triethylamine were added to the system, and stirred for reaction for 3 hours at room temperature and under N2 protection. After the reaction was completed, the solvent was removed by vacuum distillation, deionized water was added to the product, mixed evenly, and then extracted with ethyl acetate, the organic layer was taken, dried over anhydrous magnesium sulfate, filtered, and the filtrate was subjected to vacuum rotary distillation to remove ethyl acetate to obtain intermediate 3; S4. Use N2 to remove the air in the four-necked flask, add octadecane chloride, place it in an ice-water bath, and slowly drop a mixture of ethyl acetate containing intermediate 3 and triethylamine under stirring. After the addition is complete, heat to 40°C and react for 4 hours. Filter out triethylamine hydrochloride, and distill the filtrate under reduced pressure to obtain a flame retardant.

2. A weather-resistant flame-retardant PVC cable material for a charging pile according to claim 1, characterized in that: The post-treatment operation in step S1 is: remove the generated N,N-dimethylaniline hydrochloride by suction filtration, remove dioxane by vacuum distillation of the filtrate, wash twice with distilled water, separate the lower organic phase, then add ethyl acetate, dry with anhydrous sodium sulfate, filter, remove ethyl acetate by vacuum distillation of the filtrate, and complete the post-treatment process.

3. A weather-resistant flame-retardant PVC cable material for a charging pile according to claim 1, characterized in that: In step S1, the ratio of hexachlorocyclotriphosphazene, N,N-dimethylaniline and 2-hydroxymethyl-1,3-propanediol used is 10.4 g:21.8 g:9.6 g.

4. A weather-resistant flame-retardant PVC cable material for a charging pile according to claim 1, characterized in that: In step S2, the ratio of the amount of intermediate 1, N-hydroxyphthalimide and copper oxide is 13.4 g:0.98 g:1.1 g; and the oxygen flow rate is 20 mL / min.

5. The weather-resistant and flame-retardant PVC cable material for a charging pile according to claim 1, characterized in that: In step S3, the usage ratio of DIC, intermediate 2, tetramethylpiperidinamine and triethylamine is 11.9 g:14.7 g:14.1 g:9.1 g.

6. A weather-resistant flame-retardant PVC cable material for a charging pile according to claim 1, characterized in that: In step S4, the ratio of the amount of octadecane chloride, intermediate 3 and triethylamine used is 26 g:27.1 g:9.1 g.

7. A weather-resistant flame-retardant PVC cable material for a charging pile according to claim 1, characterized in that: The plasticizer is prepared by compounding DOTP and DOP in a mass ratio of 3-4:

2.

8. The weather-resistant and flame-retardant PVC cable material for a charging pile according to claim 1, characterized in that: The lubricant is stearic acid or paraffin.

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