Preparation process of chrome-plated steel-EAA plastic composite tape and chrome-plated steel-EAA plastic composite tape

Abstract

The present application relates to the technical field of steel-plastic composite tapes, and specifically discloses a preparation process of a chrome-plated steel-EAA plastic composite tape and a chrome-plated steel-EAA plastic composite tape. The preparation process of the chrome-plated steel-EAA plastic composite tape comprises the following steps: laminating an EAA film to a chrome-plated steel strip, and hot-rolling and pressing the film at 96.3 to 240.0°C to obtain a chrome-plated steel-EAA plastic composite tape. Compared with the preparation process of a conventional extruded plastic-coated steel strip, the present application first prepares an ethylene acrylate copolymer into a film, and then performs a hot-rolling and pressing process to allow the EAA film to fully infiltrate the surface of the chrome-plated steel. The connection between the EAA film and the chrome-plated steel is mainly based on ‑C‑O‑Cr chemical bonds, supplemented by microscopic meshing, so that the bonding strength between the EAA film and the chrome-plated steel is excellent. After water resistance testing, the peeling test results show that the interfacial bonding strength of the steel-plastic composite tape can reach 6.6N / cm.

Description

Technical Field

[0001] The present application relates to the technical field of steel-plastic composite belts, and more specifically, to a preparation process of a chrome-plated steel-EAA plastic composite belt and a chrome-plated steel-EAA plastic composite belt. Background Art

[0002] Steel-plastic composite tape is the most commonly used material in the metal armor layer of 5G communication optical cables. Bonded to the sheath material, it forms a comprehensive protective layer, protecting the cable core from moisture. The performance and quality of the steel-plastic composite tape directly determine the service life of optical and electrical cables.

[0003] In the related art, the preparation of conventional steel-plastic composite strips generally includes the following steps: unwinding the steel strip and removing burrs, heating the steel strip, extruding and coating the steel strip with plastic, cooling the coated steel strip, and rewinding. In actual operation, a single-screw extruder allows molten plastic to flow out of the molten plastic flow channel of the co-extrusion die. A certain gap of 0.1-1.5mm exists between the molten plastic flow channel in the co-extrusion die and the surface of the steel strip. This gap allows the thickness of the plastic layer coating the steel strip body to be adjusted within a range of 0.1-1.5mm as needed. During this process, a coating layer with a thickness of 0.1-1.5mm can be formed as required.

[0004] Regarding the aforementioned related technologies, the presence of this gap results in a constant presence of air between the plastic melt and the steel strip during the coating process, leading to adverse effects such as bubbling between the plastic and the steel strip. This results in suboptimal adhesion of the plastic to the steel strip surface, resulting in weak adhesion. Particularly under the influence of moisture, the interfacial bonding strength of the composite strip, primarily made of chrome-plated steel, was only 4.3 N / cm after water resistance testing, failing to meet the peel strength requirement of 6.13 N / cm or higher for chrome-plated steel-plastic composite strips as specified in YDT 723.3-2007. Summary of the Invention

[0005] In order to improve the bonding strength between the chrome-plated steel and the plastic after the water resistance test of the chrome-plated steel-plastic composite belt, the present application provides a preparation process of a chrome-plated steel-EAA plastic composite belt and a chrome-plated steel-EAA plastic composite belt.

[0006] In a first aspect, the present application provides a preparation process of a chrome-plated steel-EAA plastic composite strip, which adopts the following technical solution:

[0007] The preparation process of chrome-plated steel-EAA plastic composite tape includes the following steps:

[0008] The EAA film is laminated to a chrome-plated steel strip, and hot-rolled and pressed at 96.3-240.0° C. to obtain a chrome-plated steel-EAA plastic composite strip.

[0009] By adopting the above technical solution, EAA is an ethylene acrylic acid copolymer with a melting point of 96.3°C. It will undergo oxidative degradation in the temperature range of 240-380°C. The EAA surface contains carboxyl groups, which has good polarity. The chromium coating on the surface of chrome-plated steel is easily oxidized to form chromium oxide, which has a certain degree of hydrophilicity. Therefore, the EAA plastic film can infiltrate the surface of the chrome-plated steel strip in a molten state.

[0010] The carboxyl groups on the EAA plastic film open their carbon-oxygen double bonds at hot-pressing temperatures and react with chromium oxide through oxygen atoms, ultimately forming chemical bonds in the form of -CO-Cr, which promotes interfacial bonding. Furthermore, the surface of the chrome-plated steel strip has a concave-convex structure, with an average surface roughness of 0.7±0.05μm. This surface with a certain roughness and microscopic concave-convex structure not only enables micromechanical engagement between the chrome-plated steel strip and the EAA plastic film, but also increases the contact area between the chrome-plated steel and EAA, thereby improving the mechanical properties of the composite strip.

[0011] After actual experiments, the interface bonding strength between the chrome-plated steel strip and the EAA plastic film was improved. After water resistance testing, the interface bonding strength reached 6.6N / cm.

[0012] Preferably, the pressing temperature in the hot rolling pressing step is 105-120°C.

[0013] More preferably, the pressing temperature in the hot rolling pressing step is 110°C.

[0014] By adopting the above technical solution, the lamination temperature of the chrome-plated steel strip and the EAA plastic film is optimized, thereby maintaining a good processing temperature for the EAA plastic film. At the same time, this temperature has almost no effect on the EAA plastic film, reducing the possibility of its oxidation degradation, and the composite strip always maintains excellent strength and weather resistance. This enables the chrome-plated steel-EAA composite strip to have excellent bonding strength and corrosion resistance.

[0015] Optionally, the preparation of the chrome plating layer of the chrome-plated steel strip comprises the following steps:

[0016] A chromium plating solution was prepared according to the following concentrations: 83-167 g / L Cr(HC00)3, 20-35 g / L urea, 12-18 g / L ammonium formate, 5-6 g / L citric acid, 0.1-0.3 g / L sodium lauryl sulfate, and 1.5-2.5 g / L saccharin. The solvent was water. The steel strip was heat-treated and cleaned before being immersed in the chromium plating solution. The single-filament current density was controlled at 10-15 A / dm. 2 , electroplating for 15 to 30 minutes.

[0017] By adopting the above technical solution, chromium formate is used as the main salt for electroplating. The toxicity of trivalent chromium is lower than that of hexavalent chromium, making it safer and more environmentally friendly. Urea complexes with chromium formate, and by adjusting its concentration within a suitable range and adding saccharin as an additive, the metallic chromium grains are refined, thereby enhancing the adhesion of the chromium plating layer and ensuring stable adhesion to the steel. Within this electroplating process parameter range, the chromium plating layer has a moderate surface roughness, fully covers the steel strip surface, and has a high interfacial bonding strength between the chromium-plated steel and the EAA plastic film.

[0018] Preferably, the composition of the chromium plating solution is as follows: 100g / L Cr(HCOO)3, 30g / L urea, 15g / L ammonium formate, 5-6g / L citric acid, 0.1-0.3g / L sodium lauryl sulfate, 2g / L saccharin, and the solvent is water.

[0019] Preferably, the single-filament current density in the chromium plating preparation process is 13A / dm 2 , the electroplating time is 20min.

[0020] By adopting the above technical solution, the electroplating process parameters of the chrome plating layer are optimized so that the surface roughness and thickness of the chrome plating layer are moderate, while ensuring a high interface bonding strength between the chrome-plated steel and the EAA plastic film and reducing costs.

[0021] Optionally, the chrome-plated steel strip is subjected to galvanizing treatment after the chrome plating treatment and before the hot rolling and pressing to form a chromium / zinc composite coating, and the galvanizing treatment is performed according to the following steps:

[0022] Preparation of galvanizing solution:

[0023] Prepare the zinc plating solution according to the following concentrations: 80-90 g / L zinc sulfate, 50-60 g / L ammonium sulfate, 15-20 g / L sodium silicate, 0.8-1.3 g / L cyclohexane hexaphosphate, with water as the solvent;

[0024] Preparation of chrome-plated steel strip:

[0025] The steel strip is chromium plated and then immersed in the galvanizing solution, and the single wire current density is controlled at 3 to 5 A / dm 2 , electroplating for 5 to 20 minutes.

[0026] By adopting the above technical solution, a chromium / zinc composite coating is applied to the steel strip raw material. The steel strip is first plated with a chromium layer and then with a zinc layer. The process parameters of the zinc hot-dip coating are controlled to ensure that a chromium layer of at least 40nm thickness is retained on the surface of the steel strip, so that the metallic zinc adheres to the chromium layer. Zinc is more active and easier to passivate, resulting in the surface of the steel strip being covered with zinc oxide. Zinc oxide is rod-shaped and can give the chrome-plated steel a higher surface roughness, thereby enhancing the interfacial bonding strength between the chrome-plated steel and the EAA plastic film. The chrome plating layer has a higher hardness, which helps protect the steel strip during the pressing process, thereby reducing scratches on the steel strip surface and improving the corrosion resistance of the composite strip. At the same time, the chrome plating layer helps to strengthen the bonding strength between the zinc layer and the steel strip.

[0027] In a second aspect, the present application provides a chrome-plated steel-EAA plastic composite belt, which adopts the following technical solution:

[0028] A chrome-plated steel-EAA plastic composite belt is prepared by the above-mentioned preparation process of the chrome-plated steel-EAA plastic composite belt.

[0029] By adopting the above technical solution, the composite tape prepared in the present application has excellent bonding strength and water resistance, and its performance in use is excellent.

[0030] In summary, this application has the following beneficial effects:

[0031] First, the present application directly hot-rolls and presses the chrome-plated steel and the EAA plastic film, and controls the hot-rolling and pressing temperature to 96.3 to 240.0°C, preferably to 110°C, so that the EAA plastic film can quickly melt and infiltrate the chrome-plated steel strip, thereby forming a stable connection between the EAA plastic film and the chrome-plated steel; it can also reduce the possibility of degradation of the EAA plastic film, so that the composite strip has excellent corrosion resistance.

[0032] Second, the present application uses a chromium / zinc composite coating. The chromium / zinc double-coating structure has a synergistic effect in improving the interfacial bonding strength and corrosion resistance between the steel strip and the EAA plastic film; zinc is attached to the chromium layer. Zinc is more active and easier to passivate, so that the surface of the steel strip is covered with zinc oxide. Zinc oxide is rod-shaped and can give the chrome-plated steel a higher surface roughness, thereby enhancing the interfacial bonding strength between the chrome-plated steel and the EAA plastic film. The chrome plating layer has a higher hardness, which helps to protect the steel strip during the pressing process, thereby reducing scratches on the surface of the steel strip and improving the corrosion resistance of the composite strip. DETAILED DESCRIPTION

[0033] Traditional chrome-plated steel-plastic composite tape uses chrome-plated steel as its skeleton material, bonded to the plastic through plastic co-extrusion. However, co-extrusion requires a certain gap between the plastic melt and the chrome-plated steel strip to control the thickness of the plastic melt on the chrome-plated steel strip. This gap allows air to remain in contact with the steel strip, resulting in low interfacial bonding strength between the steel strip and the plastic. This also easily allows moisture to enter, significantly reducing the water resistance of the steel-plastic composite tape.

[0034] In response to the above problems, the applicant has explored the process between the chrome-plated steel strip and the EAA plastic film, as well as the coating characteristics of the chrome-plated steel strip, and found that: there is a mechanical bite and chemical bond between the chrome-plated steel strip and the EAA plastic film, which can make the chrome-plated steel-EAA composite strip have excellent interface bonding strength. After the water resistance test, the interface bonding strength can reach more than 6.6N / cm. The principle is as follows: the melting point of EAA resin is 96.3°C, and it will undergo oxidative degradation within the temperature range of 240-380°C. The chrome plating layer on the surface of the chrome-plated steel strip is easily oxidized, and there is at least 35nm thick chromium oxide. The surface of the chrome-plated steel strip has a certain hydrophilicity; while the EAA plastic film contains a large number of carboxyl groups, which have good polarity and can infiltrate the surface of the chrome-plated steel strip in a molten state. Therefore, the EAA plastic film is directly hot-rolled and pressed with the chrome-plated steel strip, and the hot-rolling temperature is controlled within the range of 96.3 to 240°C. The EAA plastic film can maintain a good molten state and avoid oxidation degradation of the EAA plastic film.

[0035] There is a concave-convex structure on the surface of the chrome-plated steel strip, and its average surface roughness can reach 0.7±0.05μm. A surface with a certain roughness and a microscopic concave-convex structure can not only achieve micro-mechanical bite between the chrome-plated steel strip and the EAA plastic, but also increase the contact area between the chrome-plated steel and EAA, thereby improving the mechanical properties of the composite strip.

[0036] At the same time, the carboxyl groups contained in the EAA plastic film open the carbon-oxygen double bond at the hot pressing temperature and react with chromium oxide through oxygen atoms to eventually form a chemical bond in the form of -CO-Cr, which promotes interfacial bonding.

[0037] After actual experiments, the interface bonding strength between the chrome-plated steel strip and the EAA plastic film was improved, and after water resistance testing, it can reach 6.6N / cm. This application successfully solves the technical problem.

[0038] Furthermore, in the present application, a chromium / zinc composite coating is used on the steel strip body. The steel strip is first plated with a chromium layer and then with a zinc layer. The process parameters of the hot-dip zinc layer are controlled to ensure that a 40nm thick chromium layer is retained on the surface of the steel strip, so that the metallic zinc adheres to the chromium layer. Zinc is more active and easier to passivate, so that the surface of the steel is covered with zinc oxide. Zinc oxide is rod-shaped and can give the chrome-plated steel a higher surface roughness, thereby enhancing the interfacial bonding strength between the chrome-plated steel and the EAA plastic film. The chrome plating layer has a higher hardness, which helps to protect the steel strip during the pressing process, thereby reducing scratches on the surface of the steel strip. At the same time, the chrome plating layer helps to strengthen the bonding strength between the zinc layer and the steel.

[0039] Unless otherwise specified, the sources of raw materials for the examples and comparative examples of the present application are as follows:

[0040] EAA plastic film: Customized EAA resin is extruded into film with a thickness of 0.06mm;

[0041] Steel strip raw material: carbon steel.

[0042] Example

[0043] Example 1

[0044] A chrome-plated steel-EAA plastic composite tape is prepared according to the following steps:

[0045] Preparation of chrome plating solution:

[0046] A chromium plating solution was prepared according to the following concentrations: 83 g / L Cr(HC00)3, 30 g / L urea, 12 g / L ammonium formate, 5 g / L citric acid, 0.1 g / L sodium lauryl sulfate, 1.5 g / L saccharin, with water as the solvent.

[0047] Preparation of coating:

[0048] The steel strip raw material is heat treated, the heating temperature is selected to be 950℃, the isothermal transformation temperature is 580℃, and the winding speed is 50m / min;

[0049] Use degreasing agent and pickling liquid to pre-treat the outer surface of the steel strip raw material to remove oil stains, lubricants, oxide layers and impurities on the outer surface, so that the outer surface of the steel strip body reaches industrial pure outer surface;

[0050] The steel strip raw material is immersed in the chrome plating solution, and the single wire current density is controlled at 10A / dm 2 , electroplating for 15 minutes, the electroplating temperature is controlled at 25 ° C. After the electroplating is completed, the steel strip raw material is taken out and cleaned to obtain chrome-plated steel;

[0051] Preparation of composite tape:

[0052] The chrome-plated steel and the EAA plastic film are hot-rolled and pressed at a hot-rolling temperature of 96.3° C., and a chrome-plated steel-EAA plastic composite strip is obtained after cooling.

[0053] Examples 2-5

[0054] A chrome-plated steel-EAA plastic composite strip is different from Example 1 in that the hot rolling and pressing temperatures in the preparation steps of the composite strip are different, as follows:

[0055] In Example 2, the hot rolling temperature is 240°C;

[0056] In Example 3, the hot rolling temperature is 105°C;

[0057] In Example 4, the hot rolling temperature is 120°C;

[0058] In Example 5, the hot rolling temperature is 110°C.

[0059] Examples 6-8

[0060] A chrome-plated steel-EAA plastic composite strip, which differs from Example 5 in that the composition of the chrome plating solution is different;

[0061] Wherein, the chromium plating solution of Example 6 is composed as follows:

[0062] 167g / L Cr(HC00)3, 45g / L urea, 18g / L ammonium formate, 6g / L citric acid, 0.3g / L sodium lauryl sulfate, 2.5g / L saccharin, solvent is water;

[0063] Wherein, the chromium plating solution of Example 7 is composed as follows:

[0064] 100g / L Cr(HC00)3, 30g / L urea, 15g / L ammonium formate, 6g / L citric acid, 0.2g / L sodium lauryl sulfate, 2g / L saccharin, solvent is water;

[0065] Wherein, the chromium plating solution of Example 8 is composed as follows:

[0066] 140g / L Cr(HC00)3, 40g / L urea, 15g / L ammonium formate, 6g / L citric acid, 0.2g / L sodium lauryl sulfate, 2g / L saccharin, solvent is water;

[0067] Examples 9-10

[0068] A chrome-plated steel-EAA plastic composite strip, which differs from Example 8 in that the current density and electroplating time during the chrome plating process are different;

[0069] In Example 9, the steel strip raw material is immersed in the chromium plating solution, and the single-filament current density is controlled to be 15A / dm 2, electroplating for 30 minutes, the electroplating temperature is controlled at 25 ° C. After the electroplating is completed, the steel strip raw material is taken out and cleaned to obtain chrome-plated steel;

[0070] In Example 10, the steel strip raw material is immersed in the chromium plating solution, and the single-filament current density is controlled to be 13A / dm 2 , electroplating for 20 minutes, the electroplating temperature is controlled at 25 ° C. After the electroplating is completed, the steel strip raw material is taken out and cleaned to obtain chrome-plated steel;

[0071] Example 11

[0072] A chrome-plated steel-EAA plastic composite strip is different from Example 10 in that the coating structure on the surface of the steel strip raw material is different, namely, a chrome / zinc composite coating. The process is specifically carried out in the following steps:

[0073] Preparation of chrome plating solution:

[0074] A chromium plating solution was prepared according to the following concentrations: 100 g / L Cr(HC00)3, 30 g / L urea, 15 g / L ammonium formate, 6 g / L citric acid, 0.2 g / L sodium lauryl sulfate, 2 g / L saccharin, and the balance was made up by water.

[0075] Preparation of galvanizing solution:

[0076] Prepare a zinc plating solution according to the following concentrations: 80g / L zinc sulfate, 50g / L ammonium sulfate, 15g / L sodium silicate, 0.8g / L cyclohexane hexaphosphate, with water as the solvent; Preparation of the coating:

[0077] The steel strip raw material is heat treated, the heating temperature is selected to be 950℃, the isothermal transformation temperature is 580℃, and the winding speed is 50m / min;

[0078] Use degreasing agent and pickling liquid to pre-treat the outer surface of the steel strip body respectively to remove oil stains, lubricants, oxide layers and impurities on the outer surface, so that the outer surface of the steel strip body reaches industrial pure outer surface;

[0079] The steel strip raw material is immersed in the chrome plating solution, and the single wire current density is controlled at 13A / dm 2 , electroplating for 20 minutes, the electroplating temperature is controlled at 25 ° C. After the electroplating is completed, the steel strip raw material is taken out for cleaning;

[0080] Then immerse the steel strip into the galvanizing solution and control the single wire current density to 3A / dm 2 , electroplating for 20 minutes, the electroplating temperature is controlled at 25 ° C. After the electroplating is completed, the steel strip raw material is taken out and cleaned to obtain chrome-plated steel;

[0081] Preparation of composite tape:

[0082] The chrome-plated steel and the EAA plastic film are hot-rolled and pressed at a hot-rolling temperature of 110° C., and a chrome-plated steel-EAA plastic composite strip is obtained after cooling.

[0083] Examples 12-13

[0084] A chrome-plated steel-EAA plastic composite strip differs from Example 11 in that the composition of the zinc plating solution, the current density of the single filament, and the electroplating time are different, as follows;

[0085] Wherein, the zinc plating solution of Example 12 is composed as follows:

[0086] 90g / L zinc sulfate, 60g / L ammonium sulfate, 20g / L sodium silicate, 1.3g / L cyclohexane hexaphosphate, the solvent is water;

[0087] The steel strip raw material is immersed in the galvanizing solution, and the single wire current density is controlled to 5A / dm 2 , electroplating for 5 minutes, the electroplating temperature is controlled at 25 ° C. After the electroplating is completed, the steel strip raw material is taken out and cleaned to obtain chrome-plated steel;

[0088] Wherein, the zinc plating solution of Example 13 is composed as follows:

[0089] 85g / L zinc sulfate, 55g / L ammonium sulfate, 20g / L sodium silicate, 1g / L cyclohexane hexaphosphate, the solvent is water;

[0090] The steel strip raw material is immersed in the galvanizing solution, and the single wire current density is controlled to 5A / dm 2 , electroplating for 5 minutes, the electroplating temperature is controlled at 25°C. After the electroplating is completed, the steel strip raw material is taken out and cleaned to obtain chromium-plated steel.

[0091] Comparative Example

[0092] Comparative Example 1

[0093] A composite steel strip comprises a steel strip body, a zinc coating on the outer surface of the steel strip body, and an ethylene acrylate copolymer layer on the outer surface of the zinc coating. The steel strip body is made of carbon steel, is non-porous, has a straight cross-section, is 0.5 mm thick, and is 70 mm wide. The zinc coating is 30 μm thick. The ethylene acrylate copolymer layer is 180 μm thick and is composed of a copolymer of polyethylene grafted with maleic anhydride.

[0094] Prepare as follows:

[0095] Use degreasing agent and pickling liquid to pre-treat the outer surface of the steel strip body respectively to remove oil stains, lubricants, oxide layers and impurities on the outer surface, so that the outer surface of the steel strip body reaches industrial pure outer surface;

[0096] Electroplating a zinc layer on the outer surface of the steel strip with a thickness of 30μm;

[0097] Chromate treatment is used to prevent white rust from forming on the outer surface of the galvanized layer;

[0098] Preheat the galvanized steel strip to 220°C using electromagnetic induction heating;

[0099] Passing the zinc-coated steel strip through an extruder to apply an ethylene acrylate copolymer layer;

[0100] The composite steel strip is cooled to below 60°C with water and then coiled.

[0101] Comparative Example 2

[0102] A chrome-plated steel-EAA plastic composite strip is produced by the following steps:

[0103] Preparation of chrome plating solution:

[0104] A chromium plating solution was prepared according to the following concentrations: 83 g / L Cr(HC00)3, 30 g / L urea, 12 g / L ammonium formate, 5 g / L citric acid, 0.1 g / L sodium lauryl sulfate, 1.5 g / L saccharin, with the remainder made up by water.

[0105] Preparation of galvanizing solution:

[0106] Prepare a zinc plating solution according to the following concentrations: 80g / L zinc sulfate, 50g / L ammonium sulfate, 15g / L sodium silicate, and 0.8g / L cyclohexane hexaphosphate; the remainder is made up of water. Preparation of the coating:

[0107] The steel strip raw material is heat treated, the heating temperature is selected to be 950℃, the isothermal transformation temperature is 580℃, and the winding speed is 50m / min;

[0108] Use degreasing agent and pickling liquid to pre-treat the outer surface of the steel strip raw material to remove oil stains, lubricants, oxide layers and impurities on the outer surface, so that the outer surface of the steel strip body reaches industrial pure outer surface;

[0109] The steel strip raw material is immersed in the galvanizing solution, and the single wire current density is controlled to 3A / dm 2 , electroplating for 20 minutes, the electroplating temperature is controlled at 25 ° C. After the electroplating is completed, the steel strip raw material is taken out for cleaning;

[0110] Then immerse the steel strip into the chrome plating solution and control the single wire current density to 13A / dm 2 , electroplating for 20 minutes, the electroplating temperature is controlled at 25 ° C. After the electroplating is completed, the steel strip raw material is taken out and cleaned to obtain chrome-plated steel;

[0111] Preparation of composite tape:

[0112] The chrome-plated steel and the EAA plastic film are hot-rolled and pressed at a hot-rolling temperature of 96.3° C., and a chrome-plated steel-EAA plastic composite strip is obtained after cooling.

[0113] Performance testing

[0114] Detection method

[0115] The chrome-plated steel strip-EAA plastic composite strips prepared in Examples 1-11 and Comparative Examples 1-2 were tested for water resistance, appearance after peeling, and corrosion resistance according to YDT 723.3-2007.

[0116] Water resistance test conditions: test temperature 68℃, time 168h;

[0117] Corrosion resistance test conditions: test solution: concentration 0.1 mol / L HCl, temperature 25°C.

[0118] Test results

[0119] Table 1. Test results of Examples 1-11 and Comparative Examples 1-2

[0120] Test samples Adhesive strength / (N / cm) Corrosion resistance time / h Appearance after peeling Example 1 6.60 485 There are no black stripes or scratches on the surface of the steel belt Example 2 6.48 480 There are no black stripes or scratches on the surface of the steel belt Example 3 6.69 481 There are no black stripes or scratches on the surface of the steel belt Example 4 6.68 482 There are no black stripes or scratches on the surface of the steel belt Example 5 6.71 480 There are no black stripes or scratches on the surface of the steel belt Example 6 6.73 482 There are no black stripes or scratches on the surface of the steel belt Example 7 6.73 480 There are no black stripes or scratches on the surface of the steel belt Example 8 6.72 482 There are no black stripes or scratches on the surface of the steel belt Example 9 6.73 483 There are no black stripes or scratches on the surface of the steel belt Example 10 6.73 484 There are no black stripes or scratches on the surface of the steel belt Example 11 6.77 490 There are no black stripes or scratches on the surface of the steel belt Example 12 6.78 493 There are no black stripes or scratches on the surface of the steel belt Example 13 6.80 498 There are no black stripes or scratches on the surface of the steel belt Comparative Example 1 4.30 385 There are no black stripes or scratches on the surface of the steel belt Comparative Example 2 5.21 321 Scratches on the surface of the steel belt

[0121] Combining Example 1, Comparative Example 1, and Table 1, we can see that in Comparative Example 1, conventional extruded plastic-coated steel strip was used. The resulting composite strip, after water resistance testing, exhibited a bonding strength of only 4.3 N / cm, significantly lower than the bonding strength between the chrome-plated steel strip and the plastic layer after the water resistance test specified in the YDT 723.3-2007 standard. This is due to the EAA not being able to fully penetrate the steel strip surface during the extrusion coating process, leading to bubbles forming between the steel strip and the EAA resin, resulting in poor bonding strength between the steel strip and the EAA.

[0122] Combining Example 1 and Comparative Example 2 with Table 1, it can be seen that Comparative Example 2 produced a zinc / chromium composite coating on the steel strip surface. Although both Comparative Example 2 and Example 1 have a double-layer structure, the bonding strength of Comparative Example 2 is only 5.21 N / cm, and the corrosion resistance time is only 321 hours. This may be because the zinc layer cannot fully cover the steel strip raw material under the action of this galvanizing process, and the coarse crystals and loose coating result in poor bonding between the coating and the steel strip in Comparative Example 2, which easily causes problems such as coating shedding and scratching. Furthermore, the poor bonding between the coating and the steel strip and the low density of the coating allow acidic corrosive liquid to enter through the gaps in the coating via capillary action, significantly reducing the corrosion resistance of the composite strip.

[0123] Combining Examples 1-5 with Table 1, it can be seen that the hot rolling temperature of the chrome-plated steel strip and the EAA plastic film significantly affects both the bonding strength and corrosion resistance of the composite strip. The optimal hot rolling temperature is 110°C.

[0124] Combining Examples 5-8 with Table 1, it can be seen that by optimizing the composition of the chromium plating solution, current density, and electroplating time, the chromium plating layer can fully cover the surface of the steel strip at a low current density, and the bonding strength between the chromium plating layer and the steel strip surface is better.

[0125] Combining Examples 7 and 9 with Table 1, it can be seen that the chromium / zinc composite coating significantly improves the interfacial bonding strength between the steel strip and the EAA film compared to chromium plating alone. Furthermore, because the chromium coating stably and densely coats the raw steel strip, it prevents acidic liquids from penetrating between the chromium-plated steel and the EAA plastic film, resulting in better corrosion resistance.

[0126] 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 non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. The preparation process of chrome-plated steel-EAA plastic composite belt is characterized in that: The following steps are included: The EAA film is laminated to the chrome-plated steel strip, and hot-rolled and pressed at 96.3-240.0° C. to obtain a chrome-plated steel-EAA plastic composite strip; After the chrome plating treatment is completed and before the hot rolling and pressing, the chrome-plated steel strip is subjected to a galvanizing treatment to form a chromium / zinc composite coating. The galvanizing treatment is performed according to the following steps: Preparation of galvanizing solution: Prepare the zinc plating solution according to the following concentration: 80-90 g / L zinc sulfate, 50-60 g / L ammonium sulfate, 15-20 g / L sodium silicate, 0.8-1.3 g / L cyclohexane hexaphosphate, the solvent is water; Preparation of chrome-plated steel strip: The steel strip is chromium plated and then immersed in a galvanizing bath for electroplating. The current density of the single wire is controlled at 3 to 5 A / dm. 2 , electroplating for 5 to 20 minutes.

2. The process for preparing the chrome-plated steel-EAA plastic composite tape according to claim 1, characterized in that: The pressing temperature in the hot rolling pressing step is 105-120°C.

3. The process for preparing the chrome-plated steel-EAA plastic composite strip according to claim 2, characterized in that: The pressing temperature in the hot rolling pressing step is 110°C.

4. The preparation process of the chrome-plated steel-EAA plastic composite tape according to claim 1, characterized in that The preparation of the chrome coating of the chrome-plated steel strip comprises the following steps: Prepare chromium plating solution according to the following concentration: 83-167 g / L Cr(HC00)3, 30-45 g / L urea, 12-18 g / L ammonium formate, 5-6 g / L citric acid, 0.1-0.3 g / L sodium lauryl sulfate, 1.5-2.5 g / L saccharin, the solvent is water; the steel strip raw material is heat-treated and cleaned, then immersed in the chromium plating solution, and the single-filament current density is controlled at 10-15 A / dm 2 , electroplating for 15 to 30 minutes.

5. The process for preparing a chrome-plated steel-EAA plastic composite strip according to claim 4, characterized in that: The chromium plating solution is composed of: 100 g / L Cr(HCOO)3, 30 g / L urea, 15 g / L ammonium formate, 5-6 g / L citric acid, 0.1-0.3 g / L sodium lauryl sulfate, 2 g / L saccharin, and water as the solvent.

6. The process for preparing the chrome-plated steel-EAA plastic composite strip according to claim 4, characterized in that: The single-wire current density in the chromium plating preparation process is 13A / dm 2 , the electroplating time is 20min.

7. Chrome-plated steel-EAA plastic composite belt, characterized by: It is prepared by the preparation process of the chrome-plated steel-EAA plastic composite strip described in any one of claims 1-6.