Flame-retardant cable for metallurgical purposes

Abstract

The application discloses a kind of metallurgical fire-retardant cables, belong to wire and cable technical field.It is constituted by cable inner core and cable outer layer wrapped in cable inner core.The cable prepared by the application, the material of heat-resistant layer is silicone rubber, which gives the cable good heat resistance;The cable's protective sleeve material uses polypropylene as matrix, which gives the cable excellent mechanical properties and electrical insulation performance;Silicon nitride is added to the protective sleeve material, which further enhances the mechanical properties and heat resistance of the cable;The flame retardant prepared by a series of reactions contains a variety of functional groups in the molecule, greatly enhancing the flame retardancy and antioxidant properties of the cable, and the performance is long and stable;Therefore, the cable prepared by the application has excellent heat resistance, stable and efficient flame retardancy and antioxidant properties, and has important application value in the field of wire and cable technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric wires and cables, and in particular relates to a flame-retardant cable for metallurgy. Background Art

[0002] With the rapid development of modern industry, the metallurgical industry, a key pillar of the national economy, faces increasing demands for power supply and transmission equipment during production. In the daily operations of metallurgical enterprises, cables, as the core carrier of power transmission, have a direct impact on the safety, stability, and service life of production equipment. However, due to the unique conditions of the metallurgical environment, such as high temperature, high humidity, strong corrosiveness, and the presence of flammable and explosive gases, ordinary cables are unable to meet actual requirements, especially with regard to fire risk control.

[0003] Traditional cables exhibit many problems when facing extreme working conditions in metallurgical scenarios. First, the temperature inside metallurgical workshops is usually high, and ordinary cable materials (such as polyvinyl chloride or cross-linked polyethylene) tend to soften or even melt at high temperatures, causing the insulation layer to fail, thereby causing a short circuit or other electrical failure. Secondly, the metallurgical environment is often accompanied by sparks flying, metal dust accumulation, etc. These factors may become potential fire sources for igniting the outer sheath of the cable. Once a fire occurs, ordinary cables will not only be unable to prevent the spread of flames, but will also release a large amount of toxic smoke and harmful gases, seriously threatening people's lives and exacerbating property losses. In addition, the continuous production mode of the metallurgical industry requires cables to have excellent flame retardant properties to ensure that even in the case of local fires, the spread of the fire can be quickly suppressed to avoid production stoppages caused by power outages.

[0004] There are already some flame-retardant cables designed for special environments on the market, but they still have certain limitations. For example, although some flame-retardant cables have achieved good flame-retardant effects by adding halogen flame retardants, they will produce highly corrosive hydrogen halide gas when burned, causing secondary damage to human health and equipment. Although other halogen-free low-smoke flame-retardant cables have improved this problem, due to the low temperature resistance of their base materials, they are prone to aging and cracking in long-term high-temperature environments, thus affecting their service life. The mechanical strength of existing flame-retardant cables is often insufficient to cope with the frequent mechanical stress and high-temperature conditions in metallurgical environments, which limits their scope of application. Therefore, there is an urgent need to invent a high-performance flame-retardant cable specifically for the metallurgical field to meet the higher demands in the field of wire and cable technology. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a flame retardant cable for metallurgy.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The utility model relates to a flame-retardant cable for metallurgy, which consists of a cable inner core and a cable outer layer wrapped around the cable inner core.

[0008] Furthermore, the inner core of the cable comprises a conductor and an insulation layer from the inside out.

[0009] Furthermore, the outer layer of the cable comprises a heat-resistant layer and a protective sheath from the inside out.

[0010] Furthermore, the material of the wire is copper.

[0011] Furthermore, the material of the insulating layer is polyvinyl chloride.

[0012] Furthermore, the material of the heat-resistant layer is silicone rubber.

[0013] Furthermore, the space between the cable inner core and the cable outer layer is filled with glass fiber rope.

[0014] Furthermore, the material of the protective cover includes the following raw materials in parts by weight: 103-117 parts of polypropylene resin, 10-15 parts of silicon nitride, 5-15 parts of flame retardant, 0.5-1.5 parts of initiator, and 4-8 parts of lubricant.

[0015] Furthermore, the initiator is one of benzoyl peroxide and lauroyl peroxide.

[0016] Furthermore, the lubricant is one of paraffin and stearic acid.

[0017] The prepared protective cover material is based on polypropylene, which gives the protective cover excellent mechanical properties and electrical insulation properties; in addition, silicon nitride added to the raw material is a high-strength ceramic material with good heat resistance, which can enhance the mechanical properties and heat resistance of the protective cover material.

[0018] Furthermore, the flame retardant is prepared by the following steps:

[0019] Step 1, sulfathiazole and anhydrous ethanol are mixed in a round-bottom flask equipped with a stirring device, and the sulfathiazole is continuously stirred until the sulfathiazole is dissolved, followed by adding glutaraldehyde and piperidine (condensing agent), and then the device temperature is raised to 65 ° C. and stirred for 6 hours. After the reaction is completed, the filter is filtered, the filter residue is taken, and the residue is washed with anhydrous ethanol several times and then vacuum dried to obtain intermediate 1; the ratio of sulfathiazole, anhydrous ethanol, glutaraldehyde, and piperidine is 25.5 g:100 mL:12.2 g:15 mL;

[0020] Under the action of piperidine, the amino group in the sulfathiazole molecule condenses with the aldehyde group in the glutaraldehyde molecule to form an imine group (C=N Schiff base structure), and glutaraldehyde is slightly excessive to obtain intermediate product 1. The specific reaction process is shown below:

[0021]

[0022] Step 2: Add vinylguanamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde and N,N-dimethylformamide (DMF) to a round-bottom flask equipped with a stirring device, stir, then add piperidine, mix well, maintain the reaction temperature at 70°C, and keep the reaction for 8 hours. After the reaction is completed, filter and wash with anhydrous ethanol several times to obtain intermediate 2; the ratio of vinylguanamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, N,N-dimethylformamide, and piperidine is 15.2g:23.4g:100mL:15mL;

[0023] Under the action of piperidine, an amino group on vinylguanamine condenses with the aldehyde group on 3,5-di-tert-butyl-4-hydroxybenzaldehyde, and vinylguanamine is slightly in excess to obtain intermediate 2. The specific reaction process is shown below:

[0024]

[0025] Step 3, the intermediate product 1, the intermediate product 2 and N, N-dimethylformamide are added to a round-bottom flask equipped with a stirring device, and after stirring, piperidine is added, mixed evenly, and heated. When the temperature reaches 78 ° C, the temperature is kept constant and the reaction is carried out for 8 hours. Stirring is continued during the reaction. After the reaction is completed, filtering, distilling under reduced pressure to remove part of the solvent, and then purifying by column chromatography (eluent using a mixed solvent of benzene / ethyl acetate, the volume ratio of the two is 2: 5), and the eluent is removed by rotary evaporation to obtain a flame retardant; the ratio of the amount of intermediate product 1, intermediate product 2, N, N-dimethylformamide, and piperidine is 33.7 g: 35.3 g: 150 mL: 10 mL;

[0026] Under the action of the condensing agent, the aldehyde group on the intermediate product 1 and the amino group on the intermediate product 2 undergo a condensation reaction to obtain a flame retardant. The specific reaction process is as follows:

[0027]

[0028] The flame retardant molecules prepared contain a variety of flame retardant components, among which the introduced sulfur element can release strong acids such as sulfuric acid under high temperature conditions, promote the dehydration of the substrate into carbon, and can also exert excellent flame retardant properties in the condensed phase, thereby improving the flame retardant properties of the matrix. In addition, the introduced triazine structure will produce nitrogen-containing gas during combustion, which dilutes and reduces the smoke density, and self-condenses at high temperatures to form melem to make the carbon layer tight, further improving the flame retardant and smoke suppression properties of the matrix; not only that, the flame retardant molecules also contain Schiff base structures, which will undergo thermal decomposition at high temperatures, releasing nitrogen-containing gases (such as ammonia, hydrogen cyanide, etc.) or inert gases (such as nitrogen), which can dilute the concentration of combustible gases and reduce the combustion area. The oxygen content is reduced, thereby suppressing the spread of flames, and the C=N double bond in the Schiff base structure can generate a carbon-nitrogen six-membered ring at high temperature, which can synergize with the sulfur element and the triazine structure to significantly enhance the flame retardant properties of the matrix; in addition, the flame retardant molecule contains hindered phenol antioxidant components. The hindered phenol molecule contains phenolic hydroxyl group (-OH), and its ortho position is "hindered" by a bulky substituent (such as tert-butyl), which makes the phenolic hydroxyl group highly active and can effectively capture free radicals, interrupt the chain reaction, and improve the antioxidant properties of the matrix; finally, the flame retardant molecule contains unsaturated carbon-carbon double bonds, which can cross-link with the polypropylene matrix under the action of the initiator, greatly improving the stability of the flame retardant.

[0029] Beneficial effects of the present invention:

[0030] 1. The cable prepared by the present invention has a heat-resistant layer made of silicone rubber, which gives the cable good heat resistance;

[0031] 2. The protective sheath material of the cable is based on polypropylene, which gives the cable excellent mechanical properties and electrical insulation properties;

[0032] 3. Adding silicon nitride to the protective sheath material further enhances the mechanical properties and heat resistance of the cable;

[0033] 4. Flame retardants are prepared through a series of reactions. The flame retardant molecules contain multiple functional groups, which greatly enhance the flame retardancy and antioxidant properties of the cable, and the performance is long-lasting and stable;

[0034] Therefore, the cable prepared by the present invention has excellent heat resistance, stable and efficient flame retardancy and antioxidant properties, and has important application value in the field of wire and cable technology. DETAILED DESCRIPTION

[0035] 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 embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] Example 1

[0037] Preparation of flame retardant:

[0038] Step 1: 25.5 g of sulfathiazole and 100 mL of anhydrous ethanol were mixed in a round-bottom flask equipped with a stirring device, and the mixture was stirred continuously until the sulfathiazole was dissolved. Subsequently, 12.2 g of glutaraldehyde and 15 mL of piperidine were added, and the temperature of the device was raised to 65 ° C. and stirred for 6 hours. After the reaction was completed, the residue was filtered and washed with anhydrous ethanol several times, and then vacuum dried to obtain intermediate 1;

[0039] Step 2: 15.2 g of vinylguanamine, 23.4 g of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 100 mL of N,N-dimethylformamide were added to a round-bottom flask equipped with a stirring device. After stirring, 15 mL of piperidine was added and mixed evenly. The reaction temperature was maintained at 70° C. and the reaction was kept warm for 8 hours. After the reaction was completed, the mixture was filtered and washed several times with anhydrous ethanol to obtain intermediate 2.

[0040] Step 3, 33.7g of intermediate product 1, 35.3g of intermediate product 2 and 150mL of N,N-dimethylformamide were added to a round-bottom flask equipped with a stirring device, and after stirring, 10mL of piperidine was added. After mixing evenly, the mixture was heated. When the temperature reached 78°C, the temperature was kept constant and the reaction was carried out for 8h. Stirring was continued during the reaction. After the reaction was completed, the mixture was filtered, and part of the solvent was removed by distillation under reduced pressure. The mixture was then purified by column chromatography (the eluent was a mixed solvent of benzene / ethyl acetate, and the volume ratio of the two was 2:5). The eluent was removed by rotary evaporation to obtain a flame retardant.

[0041] Example 2

[0042] Preparation of flame retardant:

[0043] Step 1: 51.0 g of sulfathiazole and 200 mL of anhydrous ethanol were mixed in a round-bottom flask equipped with a stirring device and stirred continuously until the sulfathiazole was dissolved. Subsequently, 24.4 g of glutaraldehyde and 30 mL of piperidine were added, and the temperature of the device was raised to 65 ° C. and stirred for 6 hours. After the reaction was completed, the filter was filtered and the filter residue was washed several times with anhydrous ethanol and then vacuum dried to obtain intermediate 1;

[0044] Step 2: 30.4 g of vinylguanamine, 46.8 g of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 200 mL of N,N-dimethylformamide were added to a round-bottom flask equipped with a stirring device. After stirring, 30 mL of piperidine was added and mixed evenly. The reaction temperature was maintained at 70° C. and the reaction was kept warm for 8 hours. After the reaction was completed, the mixture was filtered and washed several times with anhydrous ethanol to obtain intermediate 2.

[0045] Step 3, 67.4g of intermediate product 1, 70.6g of intermediate product 2 and 300mL of N,N-dimethylformamide were added to a round-bottom flask equipped with a stirring device, and after stirring, 20mL of piperidine was added. After mixing evenly, the mixture was heated. When the temperature reached 78°C, the temperature was kept constant and the reaction was carried out for 8h. Stirring was continued during the reaction. After the reaction was completed, the mixture was filtered, and part of the solvent was removed by distillation under reduced pressure. The mixture was then purified by column chromatography (the eluent was a mixed solvent of benzene / ethyl acetate, and the volume ratio of the two was 2:5). The eluent was removed by rotary evaporation to obtain a flame retardant.

[0046] Example 3

[0047] Materials for making protective cover:

[0048] 103 g of polypropylene resin and 10 g of silicon nitride were placed in an oven and dried for 8 h. The dried polypropylene resin, silicon nitride, 5 g of the flame retardant prepared in Example 1, 0.5 g of benzoyl peroxide, and 4 g of paraffin were added to a high-speed mixer and stirred for 30 min. The mixture was added to a twin-screw extruder, melt-blended, and extruded to obtain the material for the protective cover.

[0049] Example 4

[0050] Materials for making protective cover:

[0051] 110 g of polypropylene resin and 12 g of silicon nitride were placed in an oven and dried for 8 h. The dried polypropylene resin, silicon nitride, 10 g of the flame retardant prepared in Example 2, 1.0 g of lauroyl peroxide, and 6 g of stearic acid were added to a high-speed mixer and stirred for 30 min. The mixture was added to a twin-screw extruder, melt-blended, and extruded to obtain the material for the protective cover.

[0052] Example 5

[0053] Materials for making protective cover:

[0054] 117 g of polypropylene resin and 15 g of silicon nitride were placed in an oven and dried for 8 h. The dried polypropylene resin, silicon nitride, 15 g of the flame retardant prepared in Example 2, 1.5 g of lauroyl peroxide, and 8 g of stearic acid were added to a high-speed mixer and stirred for 30 min. The mixture was then added to a twin-screw extruder, melt-blended, and extruded to obtain the material for the protective cover.

[0055] Example 6

[0056] Copper wire was used as a conductor, and polyvinyl chloride was extruded on the conductor to form an insulating layer to obtain a cable inner core. Three cable inner cores were twisted, and glass fiber rope was added as a filler during the twisting process. Then, silicone rubber was extruded to form a heat-resistant layer. Finally, 117 g of polypropylene resin and 15 g of silicon nitride were placed in an oven and dried for 8 hours. The dried polypropylene resin, silicon nitride, 15 g of the flame retardant prepared in Example 2, 1.5 g of lauroyl peroxide, and 8 g of stearic acid were added to a high-speed mixer and stirred for 30 minutes. The mixture was added to a twin-screw extruder, melt-blended, and extruded onto the surface of the heat-resistant layer to obtain a flame-retardant cable for metallurgy.

[0057] Comparative Example 1

[0058] The flame retardant in Example 5 was replaced by a commercially available flame retardant, and the remaining steps were the same as those in Example 5 to obtain a material.

[0059] Comparative Example 2

[0060] Commercially available polypropylene cable material was used.

[0061] The following performance tests were conducted on Examples 3, 4, and 5 and Comparative Examples 1 and 2 according to different test standards:

[0062] The tensile properties were determined using the national standard GB / T 1040.2-2006 “Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics”;

[0063] After the sample was placed in a 150°C environment and hot air oxidized for 72 hours, the tensile strength was measured (test standard GB / T1040.2-2006) and the tensile strength retention was calculated; tensile strength retention = tensile strength after test / tensile strength before test × 100%;

[0064] The oxidation induction time was determined using the national standard GB / T 19466.6-2009 “Plastic Differential Scanning Calorimetry”;

[0065] The limiting oxygen index of the sample is determined using the national standard GB / T 2406-2008 "Test method for combustion performance of plastics";

[0066] The limiting oxygen index of Examples 3, 4, and 5 and Comparative Example 1 after standing at room temperature for 120 days was measured using the national standard GB / T 2406-2008 "Test Method for Combustion Performance of Plastics"; and the rate of change of the limiting oxygen index was calculated; the rate of change of the limiting oxygen index = limiting oxygen index after test / limiting oxygen index before test × 100%;

[0067] The measured results are shown in the following table:

[0068]

[0069] It can be seen from the above table that the protective sheath material prepared in the embodiment of the present invention has excellent heat resistance, and its flame retardancy and antioxidant properties are stronger than those of the comparative example. Moreover, with the increase of the flame retardant content, the flame retardancy and antioxidant properties of the material are enhanced. Using it as a component of the cable can improve the corresponding performance of the cable. Therefore, the present invention has important application value in the field of wire and cable technology.

[0070] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0071] 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 described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A flame-retardant cable for metallurgy, consisting of a cable inner core and a cable outer layer wrapped around the cable inner core, characterized in that: The inner core of the cable is composed of a conductor and an insulation layer from the inside out, and the outer layer of the cable is composed of a heat-resistant layer and a protective sheath from the inside out; The material of the protective cover includes the following raw materials in parts by weight: 103-117 parts of polypropylene resin, 10-15 parts of silicon nitride, 5-15 parts of flame retardant, 0.5-1.5 parts of initiator, and 4-8 parts of lubricant; Wherein, the flame retardant is prepared by the following steps: Step 1: sulfathiazole and anhydrous ethanol were mixed in a round-bottom flask and stirred continuously until the sulfathiazole was dissolved. Glutaraldehyde and piperidine were then added and reacted at 65° C. for 6 h. After the reaction was complete, the residue was filtered, washed, and vacuum-dried to obtain intermediate 1. Step 2: Add vinylguanamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde and N,N-dimethylformamide to a round-bottom flask, stir, then add piperidine, mix well, and heat at 70°C for 8 hours. After the reaction is complete, filter and wash to obtain intermediate 2; Step 3: Add intermediate product 1, intermediate product 2 and N,N-dimethylformamide to a round-bottom flask, stir, then add piperidine, mix evenly, and heat. When the temperature reaches 78°C, maintain the temperature unchanged and react for 8 hours. Stir continuously during the reaction. After the reaction is completed, filter, distill under reduced pressure, purify by column chromatography, and rotary evaporate to obtain a flame retardant.

2. A flame-retardant cable for metallurgy according to claim 1, characterized in that: The initiator is one of benzoyl peroxide and lauroyl peroxide.

3. The flame-retardant cable for metallurgy according to claim 1, characterized in that: The lubricant is one of paraffin and stearic acid.

4. The flame-retardant cable for metallurgy according to claim 1, characterized in that: The usage ratio of sulfathiazole, anhydrous ethanol, glutaraldehyde and piperidine is 25.5 g:100 mL:12.2 g:15 mL.

5. The flame-retardant cable for metallurgy according to claim 1, characterized in that: The ratio of vinylguanamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, N,N-dimethylformamide, and piperidine is 15.2 g:23.4 g:100 mL:15 mL.

6. The flame-retardant cable for metallurgy according to claim 1, characterized in that: The ratio of the amount of intermediate product 1, intermediate product 2, N,N-dimethylformamide and piperidine is 33.7 g:35.3 g:150 mL:10 mL.

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