BTTZ fireproof cable and preparation method thereof

Abstract

The invention relates to the field of fireproof cables, and particularly discloses a BTTZ fireproof cable and a preparation method thereof. The preparation method of the BTTZ fireproof cable comprises the following steps that S1, a copper strip is sequentially subjected to uncoiling, cleaning, forming and argon arc welding to obtain a copper pipe; s2, the copper rod is subjected to film-passing stretching, and the copper rod subjected to film-passing stretching is obtained; s3, the copper pipe and the copper rod subjected to film passing and stretching are subjected to passivation treatment, and a passivated copper rod and a passivated copper rod are obtained; s4, coaxially arranging the passivated copper rod and the passivated copper pipe, filling magnesium oxide powder between the copper rod and the copper pipe, and compacting to obtain a primary cable; and S5, carrying out rolling annealing and brightening treatment on the primary cable twice to obtain the BTTZ fireproof cable. According to the preparation method of the BTTZ fireproof cable provided by the invention, the length of the BTTZ fireproof cable can be effectively increased, and the BTTZ fireproof cable has good corrosion resistance.

Description

Technical Field

[0001] The present application relates to the field of fireproof cables, and more specifically, it relates to a BTTZ fireproof cable and a preparation method thereof. Background Art

[0002] BTTZ fireproof cable is a fireproof cable composed of copper core, copper tube and inorganic insulation material. BTTZ cable has the characteristics of high temperature resistance and fireproof. It can work for a long time in 250℃ environment and can work for more than 3 hours under 950℃ flame. In addition, BTTZ fireproof cable also has excellent anti-nuclear radiation performance and shielding performance. For this reason, it is widely used in dangerous, harsh and high temperature environments such as nuclear power plants, metallurgy, chemical industry, mines, kilns, etc. However, the current process for producing BTTZ fireproof cable can only adopt the filling and drawing process, the production length is short, and the maximum length of the finished product is 100m. In order to increase the length of BTTZ fireproof cable during laying, it can only be connected by joints, which makes construction difficult. In addition, with the increase of greenhouse effect, natural oxidation in the air and some specific environments (such as oxygenated water, oxidizing acid, ammonium ion, chloride ion and high temperature, etc.) will cause some brown-red or blue-green oxidation products to be produced on the surface of BTTZ fireproof cable. The presence of this oxide has a great influence on the appearance and performance of the material. Therefore, the short length of the BTTZ fireproof cable and the problem of how to improve the corrosion resistance have become urgent issues to be solved in this field. Summary of the invention

[0003] In order to solve the problem of short length of BTTZ fireproof cables existing in the related art and improve the corrosion resistance of BTTZ fireproof cables, the present application provides a BTTZ fireproof cable and a preparation method thereof.

[0004] In a first aspect, the present application provides a method for preparing a BTTZ fireproof cable, comprising the following steps: S1, unwinding, cleaning, forming and argon arc welding the copper strip to obtain a copper tube; S2, stretching the copper rod through a film to obtain a copper rod after stretching through a film; S3, passivating the copper tube and the copper rod after film stretching to obtain a passivated copper rod and a passivated copper rod; S4, setting the passivated copper rod and the passivated copper tube coaxially, filling magnesium oxide powder between the copper rod and the copper tube and compacting them to obtain a primary cable; S5, subjecting the primary cable to two rolling annealing and brightening treatments to obtain a BTTZ fireproof cable; There is no time sequence limitation for step S1 and step S2.

[0005] The present application prepares copper tubes by argon arc welding, which can ensure that the length of the BTTZ fireproof cable reaches more than 1,000 meters. In addition, the present application passivates the copper tubes and copper rods to ensure that the copper tubes and copper rods have good corrosion resistance.

[0006] Preferably, the passivation agent of the passivation treatment includes a film-forming agent, an oxidant, an auxiliary film-forming agent and water; the film-forming agent includes benzotriazole, methylbenzotriazole, sodium molybdate, and sodium silicate; the oxidant includes a 30% H2O2 aqueous solution and a 2% potassium permanganate aqueous solution; the auxiliary film-forming agent includes polyether organic polymer compounds, phytic acid, thiourea, sodium hydroxide and urea.

[0007] The present application further ensures that the copper tube and copper rod after the passivation treatment have good corrosion resistance by limiting the composition of the passivating agent.

[0008] Preferably, the concentration of the film-forming agent is 0.2-0.6 g / 100 mL, the concentration of the auxiliary film-forming agent is 0.2-0.6 g / 100 mL, and the concentration of the oxidant is 1-3 mL / 100 mL.

[0009] The present application limits the concentration of each component in the passivator to avoid incomplete passivation or excessive corrosion of the copper tube and copper rod due to insufficient or excessive concentration of each component of the passivator, thereby further ensuring the passivation effect.

[0010] Preferably, the passivation treatment specifically comprises the following steps: grinding, polishing, pickling and soaking the copper tube and the copper rod in a passivating agent in sequence to obtain the passivated copper tube and the copper rod.

[0011] The present application can remove oil stains or impurities on copper tubes and copper rods by limiting the specific steps of the passivation treatment, further ensuring the passivation treatment effect, and effectively improving the corrosion resistance of the copper tubes and copper rods after the passivation treatment.

[0012] Preferably, the passivating agent is immersed in the immersion temperature of 20-50° C. for 30-90 seconds, and the pH of the passivating agent is 3-5.

[0013] The present application effectively ensures the passivation effect during the passivation agent immersion process by limiting the temperature and time of the passivation agent immersion and the pH of the passivation agent, thereby avoiding poor passivation effect or excessive corrosion of copper tubes and copper rods due to the immersion time and temperature and the pH of the passivation agent exceeding the range.

[0014] Preferably, the pickling solution used in the pickling is a sulfuric acid solution with a volume fraction of 15%.

[0015] The present application further ensures the pickling effect of the copper tube and the copper rod by limiting the concentration of the pickling solution, while avoiding excessive corrosion of the copper tube and the copper rod due to the excessively high pH value of the pickling solution.

[0016] Preferably, the particle size of the magnesium oxide powder is 45-180 μm.

[0017] The present application can ensure that the magnesium oxide layer has a good insulation effect by limiting the particle size of the magnesium oxide powder.

[0018] Preferably, the density of the magnesium oxide powder in the primary cable is 2.0-2.2 g / cm 3 .

[0019] The present application further ensures that the magnesium oxide layer has good insulation resistivity and anti-puncture effect by limiting the density of the magnesium oxide powder.

[0020] Preferably, the magnesium oxide powder is a dry magnesium oxide powder obtained by mixing magnesium oxide powder and polyvinyl alcohol and then removing water and binder under heating.

[0021] The present application specifies the preparation method of the magnesium oxide powder to ensure that the magnesium oxide powder is dry, thereby further improving the anti-penetration effect of the magnesium oxide layer.

[0022] In a second aspect, the present application provides a BTTZ fireproof cable, which is prepared by the aforementioned preparation method.

[0023] The BTTZ fireproof cable provided in this application has a longer length, can meet industrial needs, and has good corrosion resistance, fire resistance and insulation properties.

[0024] In summary, this application has the following beneficial effects: 1. This application prepares the copper tube by uncoiling, cleaning, forming and argon arc welding, which effectively increases the length of the copper tube, thereby increasing the length of the BTTZ fireproof cable and ensuring the composite industrial demand of the BTTZ fireproof cable.

[0025] 2. This application effectively improves the passivation effect of copper tubes and copper rods by limiting the passivation treatment, so that the copper tubes and copper rods have good corrosion resistance. DETAILED DESCRIPTION

[0026] The present application provides a method for preparing a BTTZ fireproof cable, comprising the following steps: S1. The copper strip is unrolled, cleaned, formed and argon arc welded in sequence to obtain a copper tube; S2. The copper rod is stretched through a film to obtain a copper rod after stretching through a film; S3. The copper tube and the copper rod after stretching through a film are passivated to obtain a passivated copper rod and a passivated copper rod; S4. The passivated copper rod and the passivated copper tube are coaxially arranged, and magnesium oxide powder is filled between the copper rod and the copper tube and compacted to obtain a primary cable; S5. The primary cable is subjected to two rolling annealing and brightening treatments to obtain a BTTZ fireproof cable; there is no time sequence limitation for steps S1 and S2.

[0027] In the present application, unless otherwise specified, the uncoiling, cleaning, forming, argon arc welding, film stretching, rolling annealing and brightening treatment may be carried out by methods well known to those skilled in the art.

[0028] The passivation agent of the passivation treatment of the present application preferably includes a film-forming agent, an oxidant, an auxiliary film-forming agent and water. The passivation treatment can form a dense film on the copper surface, thereby improving the corrosion resistance and oxidation resistance of the copper substrate.

[0029] The film-forming agent in the passivating agent described in the present application preferably includes benzotriazole, methylbenzotriazole, sodium molybdate, sodium silicate, and more preferably benzotriazole and / or methylbenzotriazole; the concentration of the film-forming agent is preferably 0.2-0.6g / 100mL, and more preferably 0.4g / 100mL. In the present application, the film-forming agent in the passivating agent can react with copper to form a passivation film or form an adsorption film on the copper tube and copper rod to achieve a corrosion inhibition effect.

[0030] The oxidant described in the present application preferably includes a 30% H2O2 aqueous solution and a 2% potassium permanganate aqueous solution, and more preferably a 30% H2O2 aqueous solution; the concentration of the oxidant is preferably 1-3mL / 100mL, and more preferably 2mL / 100mL. In the present application, the oxidant can oxidize the copper on the surface of the copper tube and the copper rod into an ionic state, thereby promoting the passivation process.

[0031] The auxiliary film-forming agent described in the present application preferably includes polyether organic polymer compounds, phytic acid, thiourea, sodium hydroxide and urea, and is more preferably thiourea; the concentration of the auxiliary film-forming agent is preferably 0.2-0.6g / 100mL, and is more preferably 0.4g / 100mL. In the present application, the auxiliary film-forming agent has a certain corrosion inhibition effect, and can react with the film-forming agent to further improve the passivation effect.

[0032] In the present application, the passivation treatment preferably includes the following steps: grinding, polishing, pickling and soaking the copper tube and copper rod in a passivating agent in sequence to obtain the passivated copper tube and copper rod. In a specific embodiment of the present application, the passivation treatment includes the following steps: grinding, polishing, rinsing, pickling, rinsing, soaking in a passivating agent, rinsing and drying the copper tube and copper rod in sequence with 600# sandpaper to obtain the passivated copper tube and copper rod. In the present application, the pickling can form a copper protective layer on the surface of the copper tube and copper rod, further improving the corrosion resistance.

[0033] In the present application, the temperature of the passivating agent soaking is preferably 20-50°C, more preferably 30°C, the time is preferably 30-90s, more preferably 60-90s, more preferably 90s, and the pH of the passivating agent is preferably 3-5, more preferably 4. The present application effectively ensures the passivation effect of the copper tube and the copper rod by limiting the temperature and time of the passivating agent soaking and the pH of the passivating agent, and ensures that the passivated copper tube and the copper rod have good corrosion resistance.

[0034] In the present application, during the passivation agent immersion process, the copper matrix undergoes oxidation dissolution due to the action of the oxidant to generate CuO and Cu2O, and then generates Cu atoms and Cu under the action of the acidic passivation agent immersion process. + ions, Cu atoms and Cu + Ions react with film formers to form Cu-film former polymers and Cu + -film former polymer, the Cu-film former polymer and Cu + -The film-forming agent polymer undergoes slow group rearrangement under the action of its own structure and eventually reaches a stable state. In this process, the newly produced CuO particles and Cu2O particles fill the pores of the slowly rearranged polymer and eventually form a dense passivation film.

[0035] In the present application, the particle size of the magnesium oxide powder is preferably 45-180 μm, and more preferably 100 μm; the density of the magnesium oxide powder in the primary cable is 2.0-2.2 g / cm 3 , more preferably 2.1 g / cm 3 The present application can reduce the difficulty of forming the magnesium oxide layer by limiting the particle size of the magnesium oxide powder, thereby ensuring that the magnesium oxide layer has a higher density after compaction, and further ensuring that the magnesium oxide layer has a good insulation effect.

[0036] In the present application, the magnesium oxide powder is a dry magnesium oxide powder obtained by mixing magnesium oxide powder and polyvinyl alcohol and then removing water and binder under heating. The present application prepares dry magnesium oxide powder by using magnesium oxide powder and polyvinyl alcohol, which ensures that the magnesium oxide powder is dry and effectively improves the breakdown field strength of the magnesium oxide powder, so that the magnesium oxide layer has a good insulation effect.

[0037] The present application also provides a BTTZ fireproof cable, which is prepared by the above-mentioned preparation method. In the present application, the BTTZ fireproof cable comprises a copper rod, a magnesium oxide powder layer and a copper tube arranged in sequence from the inside to the outside, and the copper tube and the copper rod are coaxially arranged.

[0038] The present application is further described in detail below with reference to the embodiments.

[0039] raw material: The benzotriazole used was chemically pure CP (Shanghai test) benzotriazole sold by Tianjin Hongyan Chemical Reagent Factory, with a CAS number of 95-14-7; Sodium molybdate uses 99% (Wokai) sodium molybdate sold by Sinopharm Chemical Reagent Co., Ltd., with a CAS number of 7631-95-0; sodium silicate uses analytical pure AR (Shanghai test) sodium silicate sold by Sinopharm Chemical Reagent Co., Ltd., with a CAS number of 13517-24-3; Urea was analytically pure AR (Shanghai test) urea sold by Sinopharm Chemical Reagent Co., Ltd., CAS No. 57-13-6; Phytic acid is 50% (Shanghai test) phytic acid sold by Tianjin Hongyan Chemical Reagent Factory, CAS No. 83-86-3; The methamphetamine is 98% (Wokai) methamphetamine sold by Sinopharm Chemical Reagent Co., Ltd., with a CAS number of 29385-43-1; Thiourea was selected from analytically pure AR (Shanghai test) thiourea sold by Sinopharm Chemical Reagent Co., Ltd., with a CAS number of 62-56-6; The H2O2 aqueous solution with a mass concentration of 30% is 30% (Shanghai test) hydrogen peroxide H2O2 sold by Sinopharm Chemical Reagent Co., Ltd., with a CAS number of 7722-84-1.

[0040] Preparation Example 1 The method for preparing dry magnesium oxide powder comprises the following steps: 100 g of magnesium oxide powder and 50 g of polyvinyl alcohol were mixed, and 500 mL of water was added. The mixture was heated and stirred at 110° C. until dry to obtain dry magnesium oxide powder. The particle size of the dry magnesium oxide powder was 100 μm.

[0041] Comparative Example 1 The method for preparing damp magnesium oxide powder comprises the following steps: The magnesium oxide powder was exposed to moisture at 50° C. and 40% RH for 48 hours to obtain moist magnesium oxide powder.

[0042] Comparative Example 2 The method for preparing dry magnesium oxide powder comprises the following steps: The magnesium oxide powder was dried at 110° C. for 24 hours to obtain dry magnesium oxide powder.

[0043] Comparative Example 3 The method for preparing magnesium oxide powder containing high dielectric constant powder comprises the following steps: After the silicon dioxide powder and magnesium oxide powder are mixed evenly, they are dried at 110°C for 24 hours to obtain magnesium oxide powder containing high dielectric constant powder. Performance test The magnesium oxide powder described in Preparation Example 1, the magnesium oxide powder described in Comparative Examples 1-2, and the magnesium oxide powder described in Comparative Example 3 were subjected to breakdown test, and the test results are shown in Table 1, wherein the breakdown test method is: respectively take the magnesium oxide powder described in Preparation Example 1, the magnesium oxide powder described in Comparative Examples 1-2, and the magnesium oxide powder described in Comparative Example 3 and place them in a stainless steel culture dish, and compact the magnesium oxide powder or magnesium oxide powder into 18mm slices with a pressure of 20MPa. Using a 100kV AC voltage source as the experimental equipment and a φ25mm spherical column electrode as the electrode, the magnesium oxide powder slice or magnesium oxide powder slice is placed in a uniform electric field, and the breakdown voltage and breakdown field strength of the slice breakdown are measured.

[0044] Table 1 Breakdown field strength measurement results project Sheet thickness Breakdown voltage(kV) Breakdown field strength (kV / mm) Preparation Example 1 1.013 3.8 3.75 Comparative Example 1 1.012 0.22 0.22 Comparative Example 2 1.009 1.92 1.90 Comparative Example 3 1.014 2.69 2.63 Combining Preparation Example 1 and Comparative Examples 1-3 and Table 1, it can be seen that the breakdown field strength of the damp magnesium oxide powder is extremely low. This is because the conductive water molecules in the magnesium oxide powder move in the thin film under voltage after being damp to form channels, making it easier to be broken down. The magnesium oxide powder in Preparation Example 1 has a higher breakdown voltage and breakdown field strength than ordinary dry magnesium oxide powder and magnesium oxide powder with high dielectric constant powder added, and has a better insulation effect.

[0045] Example 1 The preparation method of the BTTZ fireproof cable comprises the following steps: S1, unwinding, cleaning, forming and argon arc welding the copper strip to obtain a copper tube; S2, stretching the copper rod through a film to obtain a copper rod after stretching through a film; S3, grinding the copper tube described in Preparation Example 2 and the copper rod described in Preparation Example 3 with 600# sandpaper, and then polishing them, rinsing the polished copper tube and copper rod with water, pickling the rinsed copper tube and copper rod with a sulfuric acid solution with a volume fraction of 15%, and soaking the pickled copper tube and copper rod in a passivator with a pH of 4 at 30° C. for 90 seconds to obtain passivated copper tubes and copper rods, wherein the passivator includes 0.4 g / 100 mL benzotriazole, 2 mL / 100 mL H2O2 aqueous solution with a mass concentration of 30%, 0.4 g / 100 mL thiourea and water; S4, the passivated copper tube and the copper rod are coaxially arranged, the magnesium oxide powder in Preparation Example 1 is filled between the copper tube and the copper rod and compacted to obtain a primary cable, wherein the density of the magnesium oxide powder in the primary cable is 2.1 g / cm 3 ; S5. The primary cable is subjected to two rolling returns and brightening treatments to obtain the BTTZ fireproof cable.

[0046] Embodiment 2-8 The difference between Example 2-8 and Example 1 is that the raw material ratios are different. The passivating agent components of Examples 1-8 are shown in Table 2.

[0047] Table 2 Passivating agent composition table of Examples 1-8 The performance test was conducted to test the passivation effect of the BTTZ fireproof cable described in Examples 1-8, and the test results are shown in Table 3. The passivation test process includes the following steps: 50 mL of concentrated nitric acid is slowly added to 100 mL of deionized water to obtain a corrosive solution, and the copper tube and copper rod are corroded by the corrosive solution for 20 seconds, and the macroscopic morphology of the copper tube and copper rod before and after corrosion is observed.

[0048] Table 3 Passivation effect test table of BTTZ fireproof cable described in Examples 1-8 In combination with Examples 1-8 and Table 3, it can be seen that the BTTZ fireproof cable described in Examples 1-6 has good corrosion resistance, and the passivator and the corresponding passivation process did not cause corrosion to the copper rod or copper tube of the fireproof cable. It can be seen from Example 7 that the passivator caused corrosion to the BTTZ fireproof cable in Example 7, and further corrosion occurred in the subsequent corrosion liquid corrosion process. It can be seen from Example 8 that although the passivator caused corrosion to the BTTZ fireproof cable in Example 8, its passivation effect was poor, and obvious corrosion points appeared in the subsequent corrosion liquid corrosion process. Therefore, the BTTZ fireproof cables described in Examples 1-6 have better performance, and the corrosion resistance of Example 1 or 2 is better.

[0049] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing a BTTZ fireproof cable, characterized in that: The following steps are involved: S1, unwinding, cleaning, forming and argon arc welding the copper strip to obtain a copper tube; S2, stretching the copper rod through a film to obtain a copper rod after stretching through a film; S3, passivating the copper tube and the copper rod after film stretching to obtain a passivated copper rod and a passivated copper rod; S4, setting the passivated copper rod and the passivated copper tube coaxially, filling magnesium oxide powder between the copper rod and the copper tube and compacting them to obtain a primary cable; S5, subjecting the primary cable to two rolling annealing and brightening treatments to obtain a BTTZ fireproof cable; There is no time sequence limitation for step S1 and step S2.

2. The preparation method according to claim 1, characterized in that: The passivation agent for the passivation treatment includes a film-forming agent, an oxidant, an auxiliary film-forming agent and water; The film-forming agent includes benzotriazole, methylbenzotriazole, sodium molybdate and sodium silicate; The oxidant includes a 30% H2O2 aqueous solution and a 2% potassium permanganate aqueous solution; The auxiliary film-forming agent comprises polyether organic macromolecular compound, phytic acid, thiourea, sodium hydroxide and urea.

3. The preparation method according to claim 2, characterized in that: The concentration of the film-forming agent is 0.2-0.6 g / 100 mL, the concentration of the auxiliary film-forming agent is 0.2-0.6 g / 100 mL, and the concentration of the oxidant is 1-3 mL / 100 mL.

4. The preparation method according to claim 1, characterized in that: The passivation treatment specifically comprises the following steps: The copper tube and the copper rod are successively ground, polished, pickled and soaked in a passivating agent to obtain the passivated copper tube and the copper rod.

5. The preparation method according to claim 4, characterized in that: The passivating agent is immersed in a temperature of 20-50° C. for 30-90 seconds, and the pH of the passivating agent is 3-5.

6. The preparation method according to claim 4, characterized in that: The pickling solution used in the pickling is a sulfuric acid solution with a volume fraction of 15%.

7. The preparation method according to claim 1, characterized in that: The particle size of the magnesium oxide powder is 45-180 μm.

8. The preparation method according to claim 1, characterized in that: The density of the magnesium oxide powder in the primary cable is 2.0-2.2 g / cm 3 .

9. The preparation method according to claim 1, characterized in that: The magnesium oxide powder is a dry magnesium oxide powder obtained by mixing magnesium oxide powder and polyvinyl alcohol and removing water and binder under heating.

10. A BTTZ fireproof cable, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 9.

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