Flame-retardant cable for metallurgy

Abstract

The invention discloses a flame-retardant cable for metallurgy, and belongs to the technical field of wires and cables. The cable is composed of a cable inner core and a cable outer layer wrapping the cable inner core. According to the cable prepared by the invention, the material of the heat-resistant layer is silicone rubber, so that the cable is endowed with good heat resistance; the protective sleeve material of the cable takes polypropylene as a matrix, so that the cable is endowed with excellent mechanical property and electrical insulation property; silicon nitride is added into the protective sleeve material, so that the mechanical property and the heat resistance of the cable are further enhanced; the flame retardant is prepared through a series of reactions, molecules of the flame retardant contain multiple functional groups, the flame retardance and oxidation resistance of the cable are greatly enhanced, and the performance is long and stable; therefore, the cable prepared by the invention is excellent in heat resistance, also has stable and efficient flame retardance and oxidation resistance, and has important application value in the technical field of wires and cables.

Description

Technical Field

[0001] The 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, as an important pillar industry of the national economy, has increasingly higher requirements for power supply and transmission equipment in the production process. In the daily operation 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 special conditions of the metallurgical environment such as high temperature, high humidity, strong corrosion and the presence of flammable and explosive gases, ordinary cables are difficult to meet actual needs, especially in terms of fire risk control.

[0003] Traditional cables exhibit many problems when facing extreme working conditions in metallurgical scenarios. First, the temperature in 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 short circuits or other electrical failures. Secondly, metallurgical environments are often accompanied by sparks flying, metal dust accumulation, and other factors, which may become potential sources of fire for igniting the outer sheath of the cable. Once a fire occurs, ordinary cables will not only fail 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 level 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, limiting their scope of application. Therefore, it is urgent 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 outside the cable inner core.

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

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

[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 it is dissolved, and then glutaraldehyde and piperidine (condensing agent) are added, and the temperature of the device is raised to 65° C., and the reaction is stirred for 6 hours. After the reaction is completed, the filter is filtered, and the filter residue is taken, and the residue is washed with anhydrous ethanol for several times, and then vacuum dried to obtain an intermediate product 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 an intermediate product 1; the specific reaction process is as follows:

[0021]

[0022] Step 2, adding vinylguanamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde and N,N-dimethylformamide (DMF) to a round-bottom flask equipped with a stirring device, stirring, then adding piperidine, mixing evenly, maintaining the reaction temperature at 70°C, and heat-retaining the reaction for 8 hours. After the reaction is completed, filtering, washing with anhydrous ethanol for several times to obtain intermediate product 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 as follows:

[0024]

[0025] Step 3, adding intermediate product 1, intermediate product 2 and N, N-dimethylformamide to a round-bottom flask equipped with a stirring device, stirring, then adding piperidine, mixing evenly, heating, and when the temperature reaches 78 ° C, keeping the temperature unchanged, reacting for 8 hours, stirring continuously during the reaction, filtering after the reaction is completed, and removing part of the solvent by reduced pressure distillation, and then purifying by column chromatography (eluent using a mixed solvent of benzene / ethyl acetate, the volume ratio of the two is 2:5), rotary evaporation to remove the eluent, and obtaining a flame retardant; the ratio of the amount of intermediate product 1, intermediate product 2, N, N-dimethylformamide, and piperidine is 33.7g:35.3g:150mL:10mL;

[0026] Under the action of the condensation 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 substrate. 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 substrate; not only that, the flame retardant molecules also contain Schiff base structures, which will undergo thermal decomposition at high temperatures to release 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 increased, thereby inhibiting 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, and 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 have higher activity and can effectively capture free radicals, interrupt chain reactions, 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 an 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 obtained through a series of reactions. The flame retardant molecules contain a variety of functional groups, which greatly enhance the flame retardancy and antioxidant properties of the cable, and the performance is long-term 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 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.

[0036] Embodiment 1

[0037] Preparation of flame retardant:

[0038] Step 1, 25.5 g of sulfathiazole and 100 mL of anhydrous ethanol are mixed in a round-bottom flask equipped with a stirring device, and the sulfathiazole is continuously stirred until it is dissolved, followed by adding 12.2 g of glutaraldehyde and 15 mL of piperidine, and then the temperature of the device is raised to 65 ° C., and the reaction is stirred for 6 hours. After the reaction is completed, the filter is filtered, the filter residue is taken, and it is washed with anhydrous ethanol for several times, and then vacuum dried to obtain an intermediate product 1;

[0039] Step 2, add 15.2g of vinylguanamine, 23.4g of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 100mL of N,N-dimethylformamide to a round-bottom flask equipped with a stirring device, stir, then add 15mL of piperidine, mix well, maintain the reaction temperature at 70°C, keep warm for 8h, filter after the reaction is completed, wash with anhydrous ethanol several times, and obtain intermediate 2;

[0040] Step 3, add 33.7g intermediate product 1, 35.3g intermediate product 2 and 150mL N, N-dimethylformamide into a round-bottom flask equipped with a stirring device, stir, then add 10mL piperidine, mix well, and heat. When the temperature reaches 78°C, keep the temperature unchanged and react for 8h. Stir continuously during the reaction. After the reaction is completed, filter, remove part of the solvent by vacuum distillation, and then purify by column chromatography (the eluent is a mixed solvent of benzene / ethyl acetate, and the volume ratio of the two is 2:5), and remove the eluent by rotary evaporation to obtain a flame retardant.

[0041] Embodiment 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 the sulfathiazole was continuously stirred until it was dissolved, and then 24.4 g of glutaraldehyde and 30 mL of piperidine were added, and the temperature of the device was raised to 65 ° C., and the reaction was stirred for 6 hours. After the reaction was completed, the filter was filtered, the filter residue was taken, and it was washed with anhydrous ethanol for several times, and then vacuum dried to obtain an intermediate product 1;

[0044] Step 2, add 30.4g of vinylguanamine, 46.8g of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 200mL of N,N-dimethylformamide to a round-bottom flask equipped with a stirring device, stir, then add 30mL of piperidine, mix well, maintain the reaction temperature at 70°C, keep the reaction for 8h, filter after the reaction is completed, wash with anhydrous ethanol several times, and obtain intermediate 2;

[0045] Step 3, 67.4g of intermediate product 1, 70.6g of intermediate product 2 and 300mL of N,N-dimethylformamide are added to a round-bottom flask equipped with a stirring device, and after stirring, 20mL of piperidine is added. After mixing evenly, heating is performed. When the temperature reaches 78°C, the temperature is kept unchanged and the reaction is performed for 8h. Stirring is continued during the reaction. After the reaction is completed, filtering is performed, and part of the solvent is removed by vacuum distillation. Then, purification is performed by column chromatography (the eluent is a mixed solvent of benzene / ethyl acetate, and the volume ratio of the two is 2:5), and the eluent is removed by rotary evaporation to obtain a flame retardant.

[0046] Embodiment 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 of the protective cover.

[0049] Embodiment 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 of the protective cover.

[0052] Embodiment 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 added to a twin-screw extruder, melt-blended and extruded to obtain the material of the protective cover.

[0055] Embodiment 6

[0056] Copper wire is used as a conductor, polyvinyl chloride is extruded on the conductor to form an insulating layer to obtain a cable inner core, three cable inner cores are twisted, and glass fiber rope is added as a filler during the twisting process, and then silicone rubber is extruded to form a heat-resistant layer, and finally 117g of polypropylene resin and 15g of silicon nitride are placed in an oven for drying for 8h, and the dried polypropylene resin, silicon nitride and 15g of the flame retardant prepared in Example 2, 1.5g of lauroyl peroxide and 8g of stearic acid are added to a high-speed mixer, stirred for 30min, 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] A commercially available flame retardant was used to replace the flame retardant in Example 5, 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 performed on Examples 3, 4, 5, and Comparative Examples 1 and 2 according to different test standards:

[0062] The tensile properties are 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] The sample was placed in an environment of 150°C and oxidized with hot air for 72 hours, and then the tensile strength was measured (test standard GB / T1040.2-2006), and the retention rate of tensile strength was calculated; the retention rate of tensile strength = 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 national standard GB / T 2406-2008 "Test method for combustion performance of plastics" is used to determine the limiting oxygen index of the sample;

[0066] The national standard GB / T 2406-2008 "Test Method for Combustion Performance of Plastics" was used to measure the limiting oxygen index of Examples 3, 4, 5 and Comparative Example 1 after standing at room temperature for 120 days; and the change rate of the limiting oxygen index was calculated; the change rate 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 a 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] 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.

[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 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 flame-retardant cable for metallurgy, comprising a cable inner core and a cable outer layer wrapped around the cable inner core, characterized in that: The inner core of the cable comprises a conductor and an insulating layer from the inside to the outside, and the outer layer of the cable comprises a heat-resistant layer and a protective sheath from the inside to the outside.

2. A flame-retardant cable for metallurgy according to claim 1, characterized in that: The material of the protective cover comprises 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.

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

4. A flame-retardant cable for metallurgy according to claim 2, characterized in that: The lubricant is one of paraffin and stearic acid.

5. A flame-retardant cable for metallurgy according to claim 2, characterized in that: The flame retardant is prepared by the following steps: Step 1, sulfathiazole and anhydrous ethanol are mixed in a round-bottom flask, and the sulfathiazole is continuously stirred until it is dissolved, and then glutaraldehyde and piperidine are added, and the mixture is stirred at 65° C. for 6 hours. After the reaction is completed, the mixture is filtered, the residue is collected, washed, and vacuum dried to obtain an intermediate product 1; Step 2, adding vinylguanamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde and N,N-dimethylformamide into a round-bottom flask, stirring, then adding piperidine, mixing evenly, and reacting at 70° C. for 8 hours. After the reaction is completed, filtering and washing to obtain intermediate product 2; Step 3, add intermediate product 1, intermediate product 2 and N, N-dimethylformamide into a round-bottom flask, stir, then add piperidine, mix well, and heat. When the temperature reaches 78°C, keep 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.

6. A flame-retardant cable for metallurgy according to claim 5, characterized in that: The usage ratio of sulfathiazole, anhydrous ethanol, glutaraldehyde and piperidine is 25.5g:100mL:12.2g:15mL.

7. The flame-retardant cable for metallurgy according to claim 5, characterized in that: The usage 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.

8. The flame-retardant cable for metallurgy according to claim 5, characterized in that: The usage ratio of intermediate product 1, intermediate product 2, N,N-dimethylformamide and piperidine is 33.7 g:35.3 g:150 mL:10 mL.

Images