Railway steel rail anti-corrosion adhesive tape and preparation method thereof

Abstract

The invention provides a railway steel rail anti-corrosion adhesive tape and a preparation method thereof. The anti-corrosion adhesive tape for the railway steel rail consists of the following three parts: zinc foil; the conductive adhesive is in close contact with the zinc foil and is used for enhancing the anti-corrosion performance and providing electric connection; and the release paper covers the conductive adhesive and is used for protecting the integrity of the conductive adhesive before use and facilitating the application of the adhesive tape. The anti-corrosion adhesive tape for the railway steel rail is used at the rail bottom and the rail web of the steel rail, spraying and heat treatment are not needed, construction is convenient and fast, sand blasting treatment on a base body is not needed, field application can be achieved without any training, and the anti-corrosion adhesive tape has high adhesive force, high corrosion resistance, high weather resistance and low comprehensive cost, and can effectively prevent steel rail corrosion in a heavy load environment.

Description

Technical Field

[0001] The present invention relates to an anti-corrosion tape for railway rails and a preparation method thereof. Background Art

[0002] In recent years, with the continuous advancement of railway engineering construction, the problem of rail corrosion failure has also become a non-negligible issue restricting the safe operation of heavy-haul railways.

[0003] When rails are long-term exposed to complex corrosion environments such as humidity, rainfall, polluted gases, acid-base-salt solutions, etc., serious corrosion phenomena will occur. Corrosion will cause the surface of the rails to become loose, the effective cross-sectional area to decrease, and the mechanical properties to deteriorate. There may even be sudden rail breaks, leading to transportation safety problems. Research has found that the rusting of the rail waist and rail bottom in the rail structure is particularly serious. The corrosion pits generated by the rusting of the rail bottom will cause local stress concentration on the rails, triggering corrosion fatigue fractures of the rails. Frequent rail replacement not only increases the working intensity of workers, but also significantly affects the normal railway transportation plan arrangement and increases the overall railway maintenance cost. Among them, the cost generated by the rail replacement skylight is much higher than the cost of the rails.

[0004] Common anti-corrosion coatings for rails are divided into the following types: zinc-rich anti-corrosion coatings, which are divided into two pretreatment and spraying processes of phosphating and sandblasting, with low production efficiency; water-based coatings, which are suitable for short-term anti-corrosion, have poor adhesion and poor aging resistance. When using water-based coatings for painting, the dry film thickness of the coating on the rail surface is 30±10μm, with relatively high production efficiency, low cost, and a transparent coating. However, the thickness of the coating on the rail bottom cannot be guaranteed, and it can only meet the anti-rust requirement for half a year; oil-based anti-corrosion coatings, which have excellent impact and friction resistance, but have a short anti-corrosion period and need to be repeatedly coated regularly, with high labor costs and great environmental protection pressure; heavy anti-corrosion coatings: can achieve long-term anti-corrosion, but have high production costs, require heating the rails to 200°C, with low efficiency, and it is very difficult to carry out on-site construction. Coated rails have been applied in small batches in Europe. The service life of rails in some line parts with relatively few corrosion factors has increased by more than 1 time. In particular, zinc-aluminum coated rails represented by British Steel have been promoted abroad, and zinc-aluminum coatings are sprayed on the rail bottom and rail waist parts for anti-corrosion. However, the zinc-aluminum coating process is complex, the construction is inconvenient, it requires power sources and gas sources, and the substrate also needs to be sandblasted, and it requires trained workers to construct.

[0005] Existing anti-corrosion technologies can no longer meet the needs of the safe operation and maintenance of railway rails in severely corroded areas. Summary of the Invention

[0006] To overcome the defects of the above-mentioned existing technologies, the present invention provides a railway steel rail anti-corrosion tape and a preparation method thereof. The railway steel rail anti-corrosion tape of the present invention is used at the bottom and waist of the steel rail, without spraying and heat treatment, with convenient construction, no need for sandblasting treatment of the substrate, and can be applied on site without any training. Moreover, it has high adhesion, high corrosion resistance, and high weather resistance, can effectively prevent the corrosion of steel rails in a heavy-load environment, and has a low comprehensive cost.

[0007] The present invention is implemented by adopting the following technical solutions.

[0008] On the one hand, the present invention provides a railway steel rail anti-corrosion tape, which is composed of the following three parts:

[0009] - Zinc foil;

[0010] - Conductive adhesive in close contact with the zinc foil, used to enhance the anti-corrosion performance and provide electrical connection; and

[0011] - Release paper covering the conductive adhesive, used to protect the integrity of the conductive adhesive before use and facilitate the application of the tape.

[0012] During use, remove the release paper, and then attach the conductive adhesive to the railway steel rail. That's it.

[0013] Preferably, the thickness of the zinc foil is 0.05 - 3 mm. Preferably, by mass parts, the conductive adhesive is composed of the following components:

[0014] Silver powder: 30 - 50 parts by weight;

[0015] Copper powder: 50 - 70 parts by weight;

[0016] Graphene: 1 - 10 parts by weight;

[0017] Amino acid aqueous solution: 30 - 50 parts by weight;

[0018] Epoxy resin: 50 - 70 parts by weight;

[0019] Epoxy diluent: 10 - 30 parts by weight (used for mixing with epoxy resin);

[0020] Curing agent: 8 - 12 parts by weight;

[0021] Coupling agent: 2 - 7 parts by weight;

[0022] Tackifier: 2 - 7 parts by weight;

[0023] Solvent: 10 - 20 parts by weight.

[0024] Preferably, by mass parts, the conductive adhesive is composed of the following components:

[0025] Silver powder: 35 - 45 parts by weight;

[0026] Copper powder: 55 - 65 parts by weight;

[0027] Graphene: 3 - 7 parts by weight;

[0028] Amino acid aqueous solution: 35 - 45 parts by weight;

[0029] Epoxy resin: 55 - 65 parts by weight;

[0030] Epoxy diluent: 15 - 25 parts by weight (for mixing with epoxy resin);

[0031] Curing agent: 9 - 11 parts by weight;

[0032] Coupling agent: 4 - 6 parts by weight;

[0033] Tackifier: 4 - 6 parts by weight;

[0034] Solvent: 12 - 18 parts by weight.

[0035] Preferably, by mass parts, the electrically conductive adhesive is composed of the following components:

[0036] Silver powder: 40 parts by weight;

[0037] Copper powder: 60 parts by weight;

[0038] Graphene: 5 parts by weight;

[0039] Amino acid aqueous solution: 40 parts by weight;

[0040] Epoxy resin: 60 parts by weight;

[0041] Epoxy diluent: 20 parts by weight (for mixing with epoxy resin);

[0042] Curing agent: 10 parts by weight;

[0043] Coupling agent: 5 parts by weight;

[0044] Tackifier: 5 parts by weight;

[0045] Solvent: 15 parts by weight.

[0046] Preferably, the amino acid is selected from α - amino acids, preferably glycine.

[0047] Preferably, the concentration of the amino acid aqueous solution is 5 - 20 wt%, preferably 10 wt%.

[0048] Preferably, the epoxy resin is selected from bisphenol F type epoxy resin (NPEF - 170) and bisphenol A type epoxy resin E - 51, preferably bisphenol A type epoxy resin E - 51.

[0049] Preferably, the epoxy diluent is selected from allyl glycidyl ether (AGE).

[0050] Preferably, the curing agent is selected from polyamide curing agent (650) and anhydride curing agent (methyltetrahydrophthalic anhydride, MeTHPA), preferably polyamide curing agent (650).

[0051] Preferably, the coupling agent is selected from KH-550 (aminosilane).

[0052] Preferably, the tackifier is selected from rosin resin.

[0053] Preferably, the solvent is selected from acetone. Preferably, the preparation method of the conductive adhesive is as follows:

[0054] Step 1: Add silver powder into the amino acid aqueous solution to obtain amino acid-modified silver powder, and then add copper powder and graphene to obtain amino acid-modified conductive filler for standby;

[0055] Step 2: Mix epoxy resin and epoxy diluent evenly to obtain mixture A;

[0056] Step 3: Sequentially add a coupling agent, a curing agent and a tackifier to the mixture A obtained in Step 2, and mix to obtain mixture B;

[0057] Step 4: Add the amino acid-modified conductive filler obtained in Step 1 into the mixture B obtained in Step 3, add a solvent, and stir at room temperature until evenly mixed to obtain the product.

[0058] Preferably, in Step 1, after adding silver powder into the amino acid aqueous solution, mechanically stir at 300-500 rpm for 30-60 minutes to ensure that the amino acid is fully adsorbed on the surface of the silver powder to obtain amino acid-modified silver powder;

[0059] Preferably, in Step 1, after obtaining the amino acid-modified silver powder, perform ultrasonic treatment to break the silver powder agglomerates and improve the dispersibility;

[0060] Preferably, the power of the ultrasonic treatment is 200-300 W and the time is 20-30 minutes;

[0061] Preferably, in Step 1, after adding copper powder and graphene, continue to stir at a low speed of 200-400 rpm for 15-20 minutes to avoid the destruction of the graphene structure caused by high-speed stirring.

[0062] Preferably, in Step 2, the mixing condition is to stir the epoxy resin and the epoxy diluent at 500-800 rpm for 20-30 minutes at room temperature (25±2°C) until the system is transparent and has no stratification.

[0063] Preferably, in Step 2, the viscosity after mixing is controlled at 2000 - 4000 mPa·s, which is convenient for adding subsequent fillers.

[0064] Preferably, in Step 3, first add the coupling agent (KH-550) and stir for 10 minutes to pre-hydrolyze it; then slowly add the curing agent (polyamide 650), and finally add the tackifier (rosin resin).

[0065] Preferably, in Step 3, the conditions for mixing are: stir at a medium speed of 400 - 600 rpm for 20 - 30 minutes to avoid introducing bubbles due to violent stirring.

[0066] Preferably, in Step 3, the mixing is carried out at room temperature (≤30°C). If the ambient temperature is too high, it can be cooled in a water bath to below 25°C to prevent the premature reaction of the curing agent.

[0067] Preferably, in Step 4, add the amino acid-modified conductive filler obtained in Step 1 to the mixture B obtained in Step 3 in 2 - 3 portions. After each addition, stir at a high speed of 800 - 1000 rpm for 10 minutes to ensure that there are no visible particles to the naked eye.

[0068] Preferably, in Step 4, after adding the solvent, adjust the stirring speed to 200 - 300 rpm, and finally control the viscosity at 2000 - 2200 mPa·s.

[0069] Preferably, after the mixing in Step 4 is completed, carry out vacuum degassing for 10 - 15 minutes (vacuum degree ≤ -0.095 MPa) to eliminate the influence of bubbles on conductivity.

[0070] In the above preparation method of the conductive adhesive, the dispersion degree of the conductive filler (silver powder, copper powder, graphene) directly affects the formation of the conductive network, and an ultrasonic + mechanical stirring composite process is required to ensure no agglomeration.

[0071] On the other hand, the present invention provides a preparation method of the above railway rail anticorrosion tape, and the method includes the following steps:

[0072] Step 1: Ultrasonically clean the zinc foil successively with acetone and ethanol to remove oil stains and oxides, and obtain the treated zinc foil.

[0073] Step 2: Prepare the conductive adhesive as described above.

[0074] Step 3: Use a coater to uniformly coat the conductive adhesive obtained in Step 2 on the treated zinc foil obtained in Step 1, and cover the release paper when the conductive adhesive is not cured.

[0075] Step 4: Curing and winding.

[0076] Preferably, in step 1, the power of the ultrasonic cleaning is 200 W and the time is 10 minutes.

[0077] Preferably, in step 1, it further includes the step of passivating the zinc foil after ultrasonic cleaning in a passivation solution.

[0078] Preferably, the passivation solution refers to a 0.5 wt.% chromic acid passivation solution.

[0079] Preferably, the passivation treatment means soaking the zinc foil after ultrasonic cleaning in the passivation solution for 30 seconds, washing with water and then drying (at 60 °C for 1 hour) to enhance the corrosion resistance of the zinc foil.

[0080] Preferably, in step 3, the thickness of the adhesive layer is 0.1 - 0.3 mm.

[0081] Preferably, in step 3, the thickness of the release paper is 50 μm.

[0082] Preferably, in step 3, the release paper is covered by means of roll pressing to ensure no bubbles, wherein the pressure is 0.2 MPa and the speed is 1 m / min.

[0083] Preferably, in step 4, the curing conditions are curing at room temperature (25 °C) for 24 hours, and then optionally curing at 80 °C for 2 hours.

[0084] Preferably, in step 4, after curing, the product is slit, for example, slit into coils with a width of 50 - 100 mm, and then sealed and packaged (in an environment with humidity < 30%). On the other hand, the present invention also provides a use of the above railway rail anti-corrosion tape in railway rail anti-corrosion.

[0085] The anti-corrosion tape of the present invention is specifically used for the long-term protection of railway rails (including easily corroded parts such as the rail waist and rail bottom), and the specific application scenarios are: corrosion environments such as high humidity, salt spray (coastal railways), deicing agents (heavy-haul railways), acid rain (industrial area railways), and tunnels. Compared with the prior art, the present invention shows significant advantages in the field of railway rail anti-corrosion, and the specific advantages are as follows:

[0086] 1. Excellent adhesion and adaptability: By combining the conductive adhesive with the zinc foil with good plasticity, it not only ensures high adhesion but also perfectly adapts to the deformation and vibration of the rail, effectively resisting coating cracking and peeling, and improving the overall stability.

[0087] 2. High wear resistance: Using metallic zinc foil as the coating material greatly improves the wear resistance and extends the service life of the rail.

[0088] 3. Significant cost-effectiveness: Without changing the metallurgical composition of the rail, only through the combination of zinc foil and conductive adhesive, the cost is significantly reduced, and it is more economical than high-strength corrosion-resistant rails.

[0089] 4. Environmentally friendly: Different from oil-based high anti-corrosion coatings, the present invention uses a metal coating and conductive adhesive, completely free from environmental protection pressure, meeting the requirements of green and sustainable development.

[0090] 5. Simple and efficient construction: There is no need to heat the rail or perform complex surface treatment. It only requires simply pasting zinc foil on the bottom and waist of the rail. The operation is simple and does not require special training, significantly improving the construction efficiency.

[0091] 6. Excellent durability and anti-corrosion performance: The metal zinc foil has a pore-free design, avoiding the durability decline caused by pores. Combining with the sacrificial anode effect of the zinc foil, it provides long-lasting anti-corrosion protection.

[0092] 7. Optimization of conductive adhesive performance: By carefully selecting silver powder and copper powder as conductive fillers and mixing them in a ratio of 40%:60%, the best balance between conductivity and cost is achieved. At the same time, adding nano-carbon material graphene further improves the conductive performance.

[0093] 8. One-component conductive adhesive design: Simplifies the production process, avoids the cumbersome on-site mixing, improves the production efficiency and storage stability, and reduces performance fluctuations.

[0094] 9. Fully meet the railway requirements: The present invention is designed for the complex and harsh environment of railways. It not only has strong corrosion resistance and convenient construction, but also can effectively reduce the failure problems caused by corrosion, ensuring transportation safety, and having significant economic and social benefits.

[0095] 10. Wide temperature range adaptability: The epoxy resin of the present application, such as bisphenol A epoxy resin, is selected in the conductive adhesive, and is combined with a specific curing agent, such as polyamide curing agent (650), to form a cross-linked network with excellent high and low temperature resistance (-40°C to 120°C), which can adapt to the extreme climate along the railway. The interface between the zinc foil and the conductive adhesive is strengthened by a silane coupling agent (KH-550) to avoid interface cracking caused by temperature difference.

[0096] 11. Enhancement of anti-chemical corrosion: The pore-free design of the zinc foil (thickness preferably ≥50μm) can block the penetration of corrosion media such as acid rain and snow melting agent (containing Cl-); the inert surface and dense network of graphene (5 parts by weight) in the conductive adhesive further block chemical erosion.

[0097] 12. Anti-fatigue property under dynamic load: The tackifier (rosin resin) and flexible epoxy diluent (AGE) in the conductive adhesive formula act synergistically to endow the adhesive layer with elastic deformation ability (elongation at break ≥15%); the plastic deformation ability of the zinc foil (elongation ≥20%) matches the flexibility of the adhesive layer to buffer the periodic impact when the train passes.

[0098] 13. Quick repair ability: The one-component conductive adhesive (storage period ≥ 3 months) can be prefabricated into sheet or paste form, and combined with zinc foil to form a "ready-to-use" module;

[0099] 14. Whole-life cycle cost advantage: The expected life of the zinc foil-conductive adhesive combination is ≥ 15 years (8 - 10 years for traditional coatings), and maintenance only requires local cladding without full-line recoating; 60% of silver powder is replaced by copper powder, reducing the material cost by about 40%. At the same time, the addition of graphene further reduces the amount of silver powder used.

[0100] Through the design of the zinc foil-conductive adhesive composite system and the refined regulation of materials science (such as graphene reinforcement, optimization of copper / silver ratio, flexible resin matrix), the present invention has achieved comprehensive breakthroughs in dimensions such as anti-corrosion, mechanics, construction, and cost. In particular, it provides innovative solutions for the pain points of dynamic loads, extreme environments, electromagnetic interference, etc. in railway scenarios, and provides reliable technical support for the long life and low maintenance requirements of railway rails under the "Traffic Power" strategy of our country. The tape of the present invention adopts the collaborative design of zinc foil-conductive adhesive, in which the sacrifice of zinc serves as anodic protection, and the conductive adhesive conducts static electricity to block corrosive media. When the ratio of silver-copper-graphene composite filler of the present invention is 40:60:5, the optimal effects of conductivity-cost-durability are achieved. When preparing the conductive adhesive, the solvent content can be flexibly adjusted, and it supports scraping / spraying / ready-to-use. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] Figure 1 It is a schematic diagram of the cross-sectional structure of a railway rail, where the red part is the anti-corrosion coating part of the railway rail; and

[0102] Figure 2 It is a schematic diagram of the structure of the anti-corrosion tape for railway rails of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0103] The following specific embodiments and drawings are used to further illustrate the present invention, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field. Unless otherwise specified, the reagents and materials used in the present invention are commercially available.

[0104] The following is the method for testing conductivity involved in the following embodiments:

[0105] GB / T31838.2-2019 Dielectric and resistive properties of solid insulating materials - Part 2: Resistive properties (DC methods) - Volume resistance and volume resistivity

[0106] Example 1:

[0107] The structure of the anti-corrosion tape of the present invention is as Figure 2 shown, and it can be applied to Figure 1 the red line part shown.

[0108] The specific anti-corrosion tape structure consists of three parts:

[0109] Zinc foil thickness: 0.5 mm

[0110] Thickness of the conductive adhesive layer in contact with the zinc foil: 0.2 mm

[0111] Release paper in contact with the conductive adhesive: PET material.

[0112] Among them, the specific formula of the conductive adhesive is as follows:

[0113] Silver powder: 40 g;

[0114] Copper powder: 60 g;

[0115] Graphene: 5 g;

[0116] Amino acid aqueous solution: 40 g;

[0117] Epoxy resin: 60 g;

[0118] Epoxy diluent: 20 g (used to mix with epoxy resin to dilute the viscosity)

[0119] Curing agent: 10 g;

[0120] Coupling agent: 5 g;

[0121] Tackifier: 5 g;

[0122] Solvent: 15 g;

[0123] The preparation method of the above conductive adhesive is as follows:

[0124] Step 1: Preparation of amino acid-modified conductive filler

[0125] After adding silver powder to the amino acid aqueous solution, mechanically stir at 300 - 500 rpm for 30 - 60 minutes to ensure that the surface of the silver powder is fully adsorbed with amino acids, obtaining amino acid-modified silver powder. Subsequently, perform ultrasonic treatment (power 200 - 300 W, 20 - 30 minutes) to break the silver powder agglomerates and improve the dispersibility.

[0126] The power of the ultrasonic treatment is 200 - 300 W and the time is 20 - 30 minutes.

[0127] Add copper powder and graphene to the modified silver powder, and continue to stir at a low speed of 200 - 400 rpm for 15 - 20 minutes to avoid damage to the graphene structure caused by high-speed stirring.

[0128] Step 2: Premixing of the epoxy resin matrix

[0129] At room temperature (25±2℃), stir the epoxy resin and epoxy diluent at 500-800rpm for 20-30 minutes until the system is transparent and has no stratification. It is recommended to control the viscosity after mixing at 2000-4000mPa·s to facilitate the subsequent addition of fillers.

[0130] Step 3: Mixing of curing system and additives

[0131] First add coupling agent (KH-550) to mixture A obtained in step 2, and stir for 10 minutes to pre-hydrolyze it; then slowly add curing agent (polyamide 650), and finally add tackifier (rosin resin).

[0132] Stirring parameters: Stir at a medium speed of 400-600 rpm for 20-30 minutes to avoid introducing bubbles due to vigorous stirring.

[0133] In step 3, the mixing is performed at room temperature (≤30° C.). If the ambient temperature is too high, it can be cooled to below 25° C. in a water bath to prevent the curing agent from reacting prematurely.

[0134] Step 4: Mixing conductive filler with solvent

[0135] The amino acid modified conductive filler in step 1 is added to the mixture obtained in step 3 in 2-3 times. After each addition, the mixture is stirred at a high speed of 800-1000 rpm for 10 minutes to ensure that there are no particles visible to the naked eye.

[0136] The solvent (acetone) was gradually added according to the coating process requirements, the stirring speed was adjusted to 200-300 rpm, and the final viscosity was controlled at 2000-3000 mPa·s.

[0137] After mixing is completed, vacuum degassing is performed for 10-15 minutes (vacuum degree ≤ -0.095MPa) to eliminate the influence of bubbles on conductivity.

[0138] The preparation method of the anti-corrosion tape is as follows:

[0139] Step 1: Zinc Foil Pretreatment

[0140] 1. Surface cleaning:

[0141] The zinc foil was ultrasonically cleaned with acetone and ethanol in sequence (power 200 W, 10 minutes) to remove oil stains and oxides.

[0142] 2. Passivation treatment:

[0143] Immerse in 0.5%wt. chromic acid passivation solution for 30 seconds, wash with water and then dry (60°C, 1 hour) to enhance the corrosion resistance of the zinc foil.

[0144] Step 2: Conductive Glue Preparation

[0145] Prepare the conductive adhesive according to the above process.

[0146] Step 3: Coating and Laminating

[0147] 1. Coating Process:

[0148] Use a coater to evenly coat the conductive adhesive on the surface of the zinc foil (the thickness of the adhesive layer is 0.1 - 0.3 mm).

[0149] 2. Release Paper Lamination:

[0150] Cover the PET release paper (thickness 50 μm) when the conductive adhesive is not cured, and roll press (pressure 0.2 MPa, speed 1 m / min) to ensure no bubbles.

[0151] Step 4: Curing and Rewinding

[0152] 1. Curing Conditions:

[0153] Cure at room temperature (25 °C) for 24 hours, and then post-cure at 80 °C for 2 hours (optional).

[0154] 2. Slitting and Rewinding:

[0155] Slit the laminated tape into coils with a width of 50 - 100 mm and seal the package (in an environment with humidity < 30%).

[0156] The anti-corrosion tape of the present invention is usually in a rolled state. During construction, unfold the anti-corrosion tape, cut the required length, tear off the release paper, and directly stick it on the rail waist and rail bottom of the rail.

[0157] Example 2

[0158] Silver powder: Copper powder = 35:65 (total 100 g), and the rest is the same as in Example 1.

[0159] Example 3

[0160] Replace bisphenol A type (E-51) with bisphenol F type epoxy resin (NPEF-170), and the rest is the same as in Example 1.

[0161] Example 4

[0162] Replace polyamide 650 with an acid anhydride curing agent (methyltetrahydrophthalic anhydride, MeTHPA), and it needs to be cured at 80 °C for 2 hours, and the rest is the same as in Example 1.

[0163] Example 5

[0164] Adjust the amount of solvent (acetone) to 20 g (low viscosity, suitable for spraying), and the rest is the same as in Example 1.

[0165] Comparative Example 1

[0166] Replace the zinc foil with aluminum foil (thickness 0.5 mm), and the rest is the same as in Example 1.

[0167] Comparative Example 2

[0168] Remove graphene (5 g) and supplement with an equal amount of copper powder. The rest is the same as in Example 1.

[0169] Comparative Example 3

[0170] 10 g of silver powder and 90 g of copper powder. The rest is the same as in Example 1.

[0171] Comparative Example 4

[0172] The amount of solvent (acetone) used is 150 g. The rest is the same as in Example 1.

[0173] Comparative Example 5

[0174] Replace epoxy resin (E51) with novolac epoxy resin (F-51). The rest is the same as in Example 1.

[0175] Comparative Example 6

[0176] Replace the curing agent with dicyandiamide (DICY) (requires high-temperature curing: 160 °C / 1 h). The rest is the same as in Example 1.

[0177] Comparative Example 7

[0178] Replace the tackifier with petroleum resin (C5) and the diluent with xylene (non-reactive diluent). The rest is the same as in Example 1.

[0179] Comparative Example 8

[0180] Adjust the preparation steps of the conductive adhesive:

[0181] Cancel Step 1, and then in Step 3, first add the conductive filler, then add the curing agent and coupling agent, and finally add additives such as amino acid aqueous solution. The rest is the same as in Example 1.

[0182] Experimental Example 1

[0183] This experimental example tested the performance of the anti-corrosion tapes obtained in the above Examples 1-5 and Comparative Examples 1-8.

[0184] The test methods are as follows:

[0185] 1. Conductivity: Volume resistivity (GB / T31838.2-2019).

[0186] 2. Adhesion: Shear strength (GB / T7124).

[0187] 3. Anti-corrosion property: Neutral salt spray test (720 h, corrosion rate measurement).

[0188] 4. Abrasion resistance: Grinding wheel friction test (load 1 kg, 1000 cycles, mass loss rate).

[0189] 5. Durability: Freeze-thaw cycle (-40°C to 80°C, coating integrity after 20 cycles).

[0190] The test results are shown in the following table:

[0191]

[0192]

[0193] As can be seen from the above table, Example 1 has the best comprehensive performance in conductivity (8×10 -5 Ω·cm), adhesion (12.5 MPa) and anti-corrosion property (0.008 mm / year).

[0194] Example 4 (anhydride curing agent + high-temperature curing) exhibits higher strength and wear resistance, but requires heating equipment and is suitable for factory prefabrication.

[0195] Example 5 (low solvent content) is suitable for spraying, but the adhesion is slightly lower.

[0196] In Comparative Example 1 (aluminum foil), due to the lack of sacrificial anode effect, the anti-corrosion performance drops sharply.

[0197] In Comparative Example 2 (without graphene), the conductivity and anti-corrosion property are significantly deteriorated.

[0198] In Comparative Example 3 (low silver content), the resistivity exceeds the standard and cannot meet the requirements of railway static conductive.

[0199] In Comparative Example 4 (excessive solvent): The coating peels off.

[0200] In Comparative Example 5 (phenolic epoxy resin): The high cross-linking density leads to the brittleness of the adhesive layer. When the zinc foil and the rail deform, the interfacial stress concentration occurs, the shear strength decreases, and it completely peels off after freeze-thaw cycle.

[0201] In Comparative Example 6 (dicyandiamide curing agent): The high-temperature curing causes the thermal mismatch between the zinc foil and the adhesive layer, and microcracks are generated after cooling, resulting in an increase in the salt spray corrosion rate.

[0202] In Comparative Example 7 (petroleum resin + xylene): The compatibility between the petroleum resin and the epoxy resin is poor, the conductive network is broken, and the resistivity increases to 2×10 -4 Ω·cm.

[0203] In Comparative Example 8 (wrong order of additives): The filler is not pre-wetted by the resin, and the coupling agent (KH-550) cannot effectively modify the surface of the filler, resulting in the aggregation of silver powder and copper powder, and the conductivity decreases significantly.

[0204] It can be seen that in this application, the combination of bisphenol A epoxy resin (E-51) + polyamide curing agent (650) (Example 1) shows the best performance in room temperature curing, flexibility, and interfacial bonding strength, avoiding the brittleness or thermal stress problems of Comparative Examples 5 and 6.

[0205] The combination of rosin resin and reactive diluent (AGE) can enhance the elasticity of the adhesive layer (elongation at break 18%), while the non-reactive diluent (xylene) in Comparative Example 7 results in a porosity > 5% and a sharp drop in durability.

[0206] In addition, in the preparation process of the conductive adhesive, the process sequence is very important. The filler is pre-modified with amino acids (Step 1), and then mixed with the resin-auxiliary system (Step 4) to ensure the uniformity of the conductive network; the reverse process sequence in Comparative Example 8 increases the resistivity by 6 times.

[0207] Through systematic optimization of the formulation design (component types, proportions, process sequence) of the present invention, the limitations of traditional materials are circumvented, and it has irreplaceability in the scenario of railway rail anti-corrosion.

Claims

1. A railway rail anti-corrosion tape, which consists of the following three parts: - zinc foil; - Conductive adhesive in close contact with the zinc foil to enhance corrosion resistance and provide electrical connection; as well as - A release paper covering the conductive adhesive, used to protect the integrity of the conductive adhesive before use and to facilitate the application of the adhesive tape.

2. The anti-corrosion tape according to claim 1, wherein: The thickness of the zinc foil is 0.05 to 3 mm; Preferably, the conductive adhesive comprises the following components in parts by mass: composition: Silver powder: 30-50 parts by weight; Copper powder: 50-70 parts by weight; Graphene: 1-10 parts by weight; Amino acid aqueous solution: 30-50 parts by weight; Epoxy resin: 50-70 parts by weight; Epoxy diluent: 10-30 parts by weight; Curing agent: 8-12 parts by weight; Coupling agent: 2-7 parts by weight; Tackifier: 2-7 parts by weight; Solvent: 10-20 parts by weight; Preferably, the conductive adhesive comprises the following components in parts by mass: composition: Silver powder: 35-45 parts by weight; Copper powder: 55-65 parts by weight; Graphene: 3-7 parts by weight; Amino acid aqueous solution: 35-45 parts by weight; Epoxy resin: 55-65 parts by weight; Epoxy diluent: 15-25 parts by weight; Curing agent: 9-11 parts by weight; Coupling agent: 4-6 parts by weight; Tackifier: 4-6 parts by weight; Solvent: 12-18 parts by weight; Preferably, the conductive adhesive comprises the following components in parts by mass: composition: Silver powder: 40 parts by weight; Copper powder: 60 parts by weight; Graphene: 5 parts by weight; Amino acid aqueous solution: 40 parts by weight; Epoxy resin: 60 parts by weight; Epoxy diluent: 20 parts by weight; Curing agent: 10 parts by weight; Coupling agent: 5 parts by weight; Tackifier: 5 parts by weight; Solvent: 15 parts by weight.

3. The anti-corrosion tape according to claim 1 or 2, wherein: The amino acid is selected from α-amino acids, preferably glycine; Preferably, the concentration of the amino acid aqueous solution is 5-20wt%, preferably 10wt%; Preferably, the epoxy resin is selected from bisphenol F epoxy resin (NPEF-170) and bisphenol A epoxy resin E-51, preferably bisphenol A epoxy resin E-51; Preferably, the epoxy diluent is selected from allyl glycidyl ether (AGE); Preferably, the curing agent is selected from polyamide curing agent (650) and anhydride curing agent (methyltetrahydrophthalic anhydride, MeTHPA), preferably polyamide curing agent (650); Preferably, the coupling agent is selected from KH-550 (aminosilane); Preferably, the tackifier is selected from rosin resin; Preferably, the solvent is selected from acetone.

4. The anticorrosion tape according to any one of claims 1 to 3, wherein: The preparation method of the conductive adhesive is as follows: Step 1: adding silver powder to an amino acid aqueous solution to obtain amino acid-modified silver powder, and then adding copper powder and graphene to obtain amino acid-modified conductive filler for later use; Step 2: Evenly mix the epoxy resin and the epoxy diluent to obtain a mixture A; Step 3: adding a coupling agent, a curing agent and a tackifier to the mixture A obtained in step 2 in sequence, and mixing to obtain a mixture B; Step 4: Add the amino acid modified conductive filler obtained in step 1 to the mixture B obtained in step 3, add a solvent, and stir at room temperature until the mixture is uniformly mixed.

5. The anti-corrosion tape according to claim 4, wherein: In step 1, after adding silver powder to the amino acid aqueous solution, mechanically stirring at 300-500 rpm for 30-60 minutes to ensure that the amino acid is fully adsorbed on the surface of the silver powder to obtain amino acid-modified silver powder; Preferably, in step 1, after obtaining the amino acid-modified silver powder, ultrasonic treatment is performed to destroy silver powder agglomerates and improve dispersibility; Preferably, the ultrasonic treatment is performed at a power of 200-300 W and for a time of 20-30 minutes; Preferably, in step 1, after adding copper powder and graphene, continue stirring at a low speed of 200-400 rpm for 15-20 minutes to avoid high-speed stirring causing destruction of the graphene structure; Preferably, in step 2, the mixing condition is to stir the epoxy resin and the epoxy diluent at 500-800 rpm for 20-30 minutes at room temperature (25±2° C.) until the system is transparent and has no stratification; Preferably, in step 2, the viscosity after mixing is controlled at 2000-4000 mPa·s to facilitate the subsequent addition of fillers; Preferably, in step 3, the coupling agent (KH-550) is first added and stirred for 10 minutes to pre-hydrolyze it; then the curing agent (polyamide 650) is slowly added, and finally the tackifier (rosin resin) is added; Preferably, in step 3, the mixing conditions are: stirring at a medium speed of 400-600 rpm for 20-30 minutes, avoiding the introduction of bubbles by vigorous stirring; Preferably, in step three, the mixing is carried out at room temperature (≤30°C); Preferably, in step 4, the amino acid modified conductive filler obtained in step 1 is added to the mixture B obtained in step 3 in 2-3 times, and after each addition, the mixture is stirred at a high speed of 800-1000 rpm for 10 minutes to ensure that there are no particles visible to the naked eye; Preferably, in step 4, after adding the solvent, the stirring speed is adjusted to 200-300 rpm, and the final viscosity is controlled to 2000-2200 mPa·s; Preferably, the method further comprises step 4, after the mixing is completed, vacuum degassing for 10-15 minutes (vacuum degree ≤-0.095MPa) to eliminate the influence of bubbles on conductivity.

6. A method for preparing the railway rail anticorrosion tape according to any one of claims 1 to 5, the method comprising the following steps: Step 1: ultrasonically clean the zinc foil with acetone and ethanol in sequence to remove oil stains and oxides to obtain a treated zinc foil; Step 2: Prepare conductive adhesive; Step 3: Use a coating machine to evenly coat the conductive adhesive obtained in step 2 on the treated zinc foil obtained in step 1, and cover the conductive adhesive with release paper when it is not cured; Step 4: Curing and rolling.

7. The method according to claim 6, wherein: In step 1, the power of the ultrasonic cleaning is 200W and the time is 10 minutes; Preferably, in step 1, the method further comprises the step of passivating the zinc foil after ultrasonic cleaning in a passivation solution; Preferably, the passivation solution refers to 0.5wt% chromic acid passivation solution; Preferably, the passivation treatment refers to immersing the zinc foil after ultrasonic cleaning in a passivation solution for 30 seconds, washing with water and then drying (60° C., 1 hour) to enhance the corrosion resistance of the zinc foil.

8. The method according to claim 6 or 7, wherein: The preparation method of the conductive adhesive is as follows: Step 1: adding silver powder to an amino acid aqueous solution to obtain amino acid-modified silver powder, and then adding copper powder and graphene to obtain amino acid-modified conductive filler for later use; Step 2: Evenly mix the epoxy resin and the epoxy diluent to obtain a mixture A; Step 3: adding a coupling agent, a curing agent and a tackifier to the mixture A obtained in step 2 in sequence, and mixing to obtain a mixture B; Step 4: adding the amino acid modified conductive filler obtained in step 1 to the mixture B obtained in step 3, adding a solvent, and stirring at room temperature until the mixture is uniformly mixed; Preferably, in step 1, after adding the silver powder to the amino acid aqueous solution, mechanical stirring is performed at 300-500 rpm for 30-60 minutes to ensure that the amino acid is fully adsorbed on the surface of the silver powder to obtain amino acid-modified silver powder; Preferably, in step 1, after obtaining the amino acid-modified silver powder, ultrasonic treatment is performed to destroy silver powder agglomerates and improve dispersibility; Preferably, the ultrasonic treatment is performed at a power of 200-300 W and for a time of 20-30 minutes; Preferably, in step 1, after adding copper powder and graphene, continue stirring at a low speed of 200-400 rpm for 15-20 minutes to avoid high-speed stirring causing destruction of the graphene structure; Preferably, in step 2, the mixing condition is to stir the epoxy resin and the epoxy diluent at 500-800 rpm for 20-30 minutes at room temperature (25±2° C.) until the system is transparent and has no stratification; Preferably, in step 2, the viscosity after mixing is controlled at 2000-4000 mPa·s to facilitate the subsequent addition of fillers; Preferably, in step 3, the coupling agent (KH-550) is first added and stirred for 10 minutes to pre-hydrolyze it; then the curing agent (polyamide 650) is slowly added, and finally the tackifier (rosin resin) is added; Preferably, in step 3, the mixing conditions are: stirring at a medium speed of 400-600 rpm for 20-30 minutes, avoiding the introduction of bubbles by vigorous stirring; Preferably, in step three, the mixing is carried out at room temperature (≤30°C); Preferably, in step 4, the amino acid modified conductive filler obtained in step 1 is added to the mixture B obtained in step 3 in 2-3 times, and after each addition, the mixture is stirred at a high speed of 800-1000 rpm for 10 minutes to ensure that there are no particles visible to the naked eye; Preferably, in step 4, after adding the solvent, the stirring speed is adjusted to 200-300 rpm, and the final viscosity is controlled to 2000-2200 mPa·s; Preferably, the method further comprises step 4, after the mixing is completed, vacuum degassing for 10-15 minutes (vacuum degree ≤-0.095MPa) to eliminate the influence of bubbles on conductivity.

9. The method according to any one of claims 6 to 8, wherein: In step 3, the thickness of the adhesive layer is 0.1-0.3 mm; Preferably, in step 3, the thickness of the release paper is 50 μm; Preferably, in step 3, the release paper is covered by rolling to ensure that there are no bubbles, wherein the pressure is 0.2 MPa and the speed is 1 m / min; Preferably, in step 4, the curing conditions are curing at room temperature (25° C.) for 24 hours, and then optionally curing at 80° C. for 2 hours; Preferably, in step 4, the product is cut into pieces after curing, for example, into coils with a width of 50-100 mm, and sealed and packaged (humidity <30% environment).

10. Use of the railway rail anti-corrosion tape according to any one of claims 1 to 5 in railway rail anti-corrosion.

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