High-strength corrosion-resistant mineral woven bag substrate and preparation method thereof

Abstract

The present application relates to mine packaging materials, especially a kind of mine powder induced self-repairing corrosion-resistant mine woven bag substrate and its preparation method.The substrate is composed of polyolefin flat filament fabric and surface functional coating, and the coating has sandwich partition structure: outer wear-resistant barrier, middle layer evenly dispersed calcite and dolomite powder with particle size of 1-3 μm, containing two types of fast-release and slow-release mine powder to release Ca²⁺ / Mg²⁺ in stages, inner layer containing phosphate density of 0.30-1.20 mmol / m² phosphate or phosphonic acid functional group, and adding crystal inhibitor to control the deposition thickness at 5-10 μm.Mine powder is triggered to release Ca²⁺ / Mg²⁺ by mechanical stress and mine slurry ions, and Ca / Mg phosphate protective layer is generated in situ at the interface, and magnetic or fluorescent filler can be added to realize life visualization.The present application triggers self-repairing by using mine environment, and the protective layer continues to thicken during use, which significantly improves corrosion resistance and long-term mechanical properties, and the retention rate of warp and weft breaking strength after 30 d cycle is 95.0%-97.0%, which is better than traditional corrosion inhibition coating.

Description

Technical Field

[0001] This invention relates to the field of mining packaging materials technology, specifically to a high-strength, corrosion-resistant woven bag substrate for mining and its preparation method. Background Technology

[0002] Mining woven bags are widely used in the packaging and transportation of bulk materials such as ores, mineral powders, and concentrates due to their light weight, high strength, and ease of processing. Common mining woven bags typically use polypropylene or polyethylene flat yarn fabric as the base material, with coatings or composites used to improve their wear resistance, moisture resistance, and corrosion resistance. However, mining environments often involve acidic or alkaline slurries, salt spray, and sulfur-containing gases, which can corrode the substrate. Frequent mechanical impacts and friction during loading, unloading, stacking, and transportation can cause the coating to crack and peel off. The penetration of corrosive media accelerates the aging and strength reduction of the substrate.

[0003] Existing corrosion-resistant coatings mainly rely on increasing coating thickness, adding corrosion inhibitors, or using dense barrier membranes to slow down media penetration. However, these methods often suffer from insufficient durability, loss of protective function after local damage, and uncontrollable release of corrosion inhibitors. Once the coating is locally damaged, corrosion will rapidly spread along the defect, causing a decline in the mechanical properties of the woven bags and shortening their service life.

[0004] Therefore, there is an urgent need for a corrosion-resistant woven bag substrate that can automatically initiate a repair reaction after local damage to the coating and utilize the unique chemical conditions of the mining environment to extend its service life and maintain long-term mechanical and protective properties. Summary of the Invention

[0005] To address the shortcomings mentioned in the background art, the present invention aims to provide a mineral powder-induced self-healing corrosion-resistant woven bag substrate and its preparation method, which addresses the problems of rapid protective failure, insufficient durability, and inability to self-repair after local damage in existing mining woven bags under corrosive environments. By utilizing the unique mineral slurry ions and mechanical action in the mining environment, the coating can achieve in-situ self-repair after local damage, significantly improving the corrosion resistance and long-term mechanical stability of the woven bag.

[0006] To achieve the above objectives, the present invention provides a high-strength, corrosion-resistant woven bag substrate for mining, comprising a polyolefin flat filament fabric and a functional coating applied to its surface. The functional coating has a sandwich-partition structure and includes: A high-strength, corrosion-resistant woven bag substrate for mining, comprising polyolefin flat filament fabric and a functional coating applied to its surface, characterized in that: The functional coating has a sandwich-partition structure, including: Outer wear-resistant barrier layer; The intermediate mineral powder coating comprises the following raw materials in parts by weight: 1-4 parts of calcite mineral powder, with a particle size of 1-3 μm; 1-4 parts of dolomite mineral powder, with a particle size of 1-3 μm; 85-95 parts of coating base material, wherein the coating base material is selected from one or more of acrylic resins, polyurethane resins, their modifiers and other film-forming resins; The inner layer contains a phosphorus-based coating, which contains 0.5-2 parts of one or more of phosphate ester functional group compounds, phosphonic acid functional group compounds, and combinations thereof, so that the surface phosphorus density is 0.30-1.20 mmol / m², and contains 0.1-0.5 parts of a crystal inhibiting agent; The substrate forms a Ca / Mg phosphate protective layer with a thickness of 5-10 μm at the interface after 30 days of slurry circulation, and the retention rate of longitudinal and latitudinal fracture strength is 95.0%-97.0%, and the Ca / P molar ratio of the protective layer is 1.5-1.7.

[0007] Optionally, in the high-strength corrosion-resistant woven bag substrate for mining, the fast-release phase mineral powder accounts for 20-40% of the total mineral powder mass and the slow-release phase mineral powder accounts for 60-80% of the total mineral powder mass in the calcite and dolomite mineral powder.

[0008] Optionally, the high-strength, corrosion-resistant woven bag substrate for mining has a coating containing 0.5-2 parts of magnetic particles and one or more fluorescent marker inorganic fillers.

[0009] Optionally, in the high-strength corrosion-resistant woven bag substrate for mining, the polyolefin flat filament fabric is made of one or more of polypropylene, polyethylene and their blends, and has a stretch orientation ratio of 4.5-7.0.

[0010] Optionally, in the high-strength, corrosion-resistant woven bag substrate for mining, a maleic anhydride-grafted polypropylene undercoating with a coating amount of 0.5-2 g / m² is provided between the functional coating and the polyolefin flat filament fabric.

[0011] Optionally, the high-strength and corrosion-resistant woven bag substrate for mining retains 95.0%-97.0% of its warp and weft tensile strength after 30 days of slurry circulation, and the thickness of the Ca / Mg phosphate protective layer formed at the interface is 5-10 μm, with a Ca / P molar ratio of 1.5-1.7.

[0012] Optionally, the preparation method of the high-strength and corrosion-resistant woven bag substrate for mining is as follows: S1. Apply a primer coating to the surface of the polyolefin flat filament fabric and let it dry; S2. Prepare functional coating liquid by dispersing calcite ore powder and dolomite ore powder in the coating base in a certain proportion, and adding one or more introducing agents, crystal inhibitors and optional magnetic or fluorescent labeling fillers selected from phosphate ester functional group compounds and phosphonic acid functional group compounds. S3. Apply the sandwich-section structure to the base layer and dry at 60-90℃ to form a functional coating; S4. Tension setting at 120-135℃ to obtain the woven bag substrate.

[0013] Optionally, in the high-strength, corrosion-resistant woven bag substrate for mining, the anti-crystallization agent is selected from one or more of organic acid salts, carboxyl-containing polymers, phosphonic acid-containing compounds, phosphate compounds, and combinations thereof.

[0014] The beneficial effects of this invention are: This invention introduces fast-release and slow-release mineral powders into the coating and co-designs them with the inner phosphate / phosphonic acid functional groups. Utilizing the dual triggering of slurry ions and mechanical stress, it releases Ca²⁺ / Mg²⁺, generating a self-healing Ca / Mg phosphate protective layer in situ at the coating / base fabric interface. This protective layer can continuously thicken during service and is controlled at 5-10 μm by a crystallization inhibitor, exhibiting both sustainable repair and self-limiting growth characteristics. Even if the coating is locally damaged, it can quickly restore its barrier performance, maintaining a 95.0%-97.0% longitudinal fracture strength after 30 days of slurry circulation, significantly superior to traditional corrosion-inhibiting coatings. Simultaneously, optional magnetic or fluorescent fillers provide visualization of the protective status, enabling intuitive monitoring of service life and improving the product's durability and safety in complex mining environments. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0016] Figure 1 The curves showing the change in average strength retention rate of each sample in this invention during 0-30 days of slurry circulation are shown. Figure 2 This is a graph showing the change in scratch width over time for each sample in the cyclic corrosion test of this invention. Figure 3 The curves show the adhesion retention rate of each sample in this invention during 0-30 days of slurry circulation. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: S1. Take 70 g of polypropylene and 30 g of polyethylene, blend them and extrude them into flat filaments, with a hot stretching orientation ratio of 5.5, and weave them into a woven fabric with 12×12 threads / inch. S2. Prepare a primer solution with a mass fraction of 5-10% by maleic anhydride-grafted polypropylene (MAH-g-PP), and apply it evenly to the surface of the base fabric by scraping to achieve a dry film weight of 1.0 g / m², and dry at 60-80℃. S3. Weigh 90 g of acrylic / polyurethane (1:1 mass ratio) mixed resin as coating base material, add 1 g of calcite powder and 1 g of dolomite powder (particle size 1-3 μm, fast / slow release phase ratio 30% / 70%) in sequence, stir at 1000 rpm for 30 min until the mineral powder is completely and uniformly dispersed. S4. Weigh 8.95 g of acrylic / polyurethane mixed resin in another container, add 0.50 g of a compound containing phosphate ester or phosphonic acid functional groups (to make the surface phosphorus density 0.70 mmol / m²) and 0.30 g of crystal inhibitor (selected from citrate or polyaspartic acid), and stir at 300 rpm for 15 min. S5. Coat in the order of "outer layer - middle layer - inner layer"; dry each layer at 90℃ for 2.5-3.5 min; finally, tension set at 120-135℃, and control the total dry film thickness of the finished coating at 10-20 μm.

[0019] Example 2: S1. Take 70 g of polypropylene and 30 g of polyethylene, blend them and extrude them into flat filaments, with a hot stretching orientation ratio of 5.5, and weave them into a woven fabric with 12×12 threads / inch. S2. Prepare a primer solution with a mass fraction of 5-10% by maleic anhydride grafted polypropylene. Apply the primer solution evenly to the surface of the base fabric by scraping, so that the dry film weight is 1.0 g / m², and dry at 60-80℃. S3. Weigh 90 g of acrylic / polyurethane (1:1 mass ratio) mixed resin as coating base material, add 2 g of calcite powder and 2 g of dolomite powder (particle size 1-3 μm, fast / slow release phase ratio 30% / 70%) in sequence, stir at 1000 rpm for 30 min until the mineral powder is completely and uniformly dispersed. S4. Weigh 8.95 g of acrylic / polyurethane mixed resin in another container, add 0.50 g of a compound containing phosphate ester or phosphonic acid functional groups (to make the surface phosphorus density 0.70 mmol / m²) and 0.30 g of crystal inhibitor (selected from citrate or polyaspartic acid), and stir at 300 rpm for 15 min. S5. Coat in the order of "outer layer - middle layer - inner layer"; dry each layer at 90℃ for 2.5-3.5 min; finally, tension set at 120-135℃, and control the total dry film thickness of the finished coating at 10-20 μm.

[0020] Example 3: S1. Take 70 g of polypropylene and 30 g of polyethylene, blend them and extrude them into flat filaments, with a hot stretching orientation ratio of 5.5, and weave them into a woven fabric with 12×12 threads / inch. S2. Prepare a primer solution with a mass fraction of 5-10% by maleic anhydride grafted polypropylene. Apply the primer solution evenly to the surface of the base fabric by scraping, so that the dry film weight is 1.0 g / m², and dry at 60-80℃. S3. Weigh 90 g of acrylic / polyurethane (1:1 mass ratio) mixed resin as coating base material, add 2 g of calcite powder and 2 g of dolomite powder (particle size 1-3 μm, fast / slow release phase ratio 30% / 70%) in sequence, stir at 1000 rpm for 30 min until the mineral powder is completely and uniformly dispersed. S4. Weigh 8.95 g of acrylic / polyurethane mixed resin in another container, add 0.95 g of a compound containing phosphate ester or phosphonic acid functional groups (to make the surface phosphorus density 1.20 mmol / m²) and 0.30 g of crystal inhibitor (selected from citrate or polyaspartic acid), and stir at 300 rpm for 15 min. S5. Coat in the order of "outer layer - middle layer - inner layer"; dry each layer at 90℃ for 2.5-3.5 min; finally, tension set at 120-135℃, and control the total dry film thickness of the finished coating at 10-20 μm.

[0021] Comparative Example 1: S1. Take 70 g of polypropylene and 30 g of polyethylene, blend them and extrude them into flat filaments, with a hot stretching orientation ratio of 5.5, and weave them into a woven fabric with 12×12 threads / inch. S2. Prepare a primer solution with a mass fraction of 5-10% by maleic anhydride grafted polypropylene. Apply the primer solution evenly to the surface of the base fabric by scraping, so that the dry film weight is 1.0 g / m², and dry at 60-80℃. S3. Weigh 90 g of acrylic / polyurethane (1:1 mass ratio) mixed resin as coating base material and stir at 1000 rpm for 30 min; S4. Weigh 8.95 g of acrylic / polyurethane mixed resin in another container, add 0.50 g of a compound containing phosphate ester or phosphonic acid functional groups (to make the surface phosphorus density 0.70 mmol / m²) and 0.30 g of crystal inhibitor (selected from citrate or polyaspartic acid), and stir at 300 rpm for 15 min. S5. Coat in the order of "outer layer - middle layer - inner layer"; dry each layer at 90℃ for 2.5-3.5 min; finally, tension set at 120-135℃, and control the total dry film thickness of the finished coating at 10-20 μm.

[0022] Comparative Example 2: S1. Take 70 g of polypropylene and 30 g of polyethylene, blend them and extrude them into flat filaments, with a hot stretching orientation ratio of 5.5, and weave them into a woven fabric with 12×12 threads / inch. S2. Prepare a primer solution with a mass fraction of 5-10% by maleic anhydride grafted polypropylene. Apply the primer solution evenly to the surface of the base fabric by scraping, so that the dry film weight is 1.0 g / m², and dry at 60-80℃. S3. Weigh 90 g of acrylic / polyurethane (1:1 mass ratio) mixed resin as coating base material, add 2 g of calcite powder and 2 g of dolomite powder (particle size 1-3 μm, fast / slow release phase ratio 30% / 70%) in sequence, stir at 1000 rpm for 30 min until the mineral powder is completely and uniformly dispersed. S4. Weigh 9.45 g of acrylic / polyurethane mixed resin and 0.30 g of crystal inhibitor (selected from citrate or polyaspartic acid) into another container, and stir at 300 rpm for 15 min. S5. Coat in the order of "outer layer - middle layer - inner layer"; dry each layer at 90℃ for 2.5-3.5 min; finally, tension set at 120-135℃, and control the total dry film thickness of the finished coating at 10-20 μm.

[0023] Performance testing: 1. Strength retention rate test after slurry circulation The samples from the examples and comparative examples were cut into 50 mm × 300 mm pieces, with 5 pieces each in the warp and weft directions. The pieces were placed in a standard slurry with a solid content of 15 wt% and continuously circulated for 30 days in a circulation device at a constant temperature of 25°C and a circulation flow rate of 1 m / s. After the circulation was completed, the warp and weft breaking strengths were measured on a tensile testing machine according to the conditions specified in GB / T 3923.1 or ASTM D5035, and compared with the initial strength before the circulation to calculate the strength retention rate.

[0024] Table 1. Test results of warp / weft strength retention rate after different slurry circulation times.

[0025] The strength retention data after 30 days of slurry circulation show that the warp and weft strength of Examples 1-3 remained above 95.0% throughout the entire circulation process, which is higher than the set acceptable line, and the attenuation was small, indicating that the coating system can effectively inhibit fiber damage and strength attenuation. In contrast, the strength of Comparative Examples 1 and 2 decreased significantly after 20 days of circulation, falling below the acceptable line, indicating that the lack of mineral powder ion source or phosphorus-based functional groups will lead to insufficient protective layer deposition, significantly reducing abrasion resistance and degradation resistance, thus verifying the significant advantages of the formulation of this invention in improving fabric durability.

[0026] 2. Scratch self-healing and propagation inhibition test A single-strip defect penetrating the coating was etched along the radial direction on the surface of each sample using a standard scratching tool. The initial width of the defect was controlled at (200 ± 10) μm. The scratched samples were placed in a simulated slurry circulation device for 30 days. The solid content of the circulation medium was 40 g / L, the flow rate was 0.5 m / s, and the temperature was (25 ± 2) ℃. After the circulation was completed, the rate of change of the scratch extension radius was measured using an optical microscope, and the low-frequency impedance value was measured at 0.01 Hz using electrochemical impedance spectroscopy (EIS). The improvement factor was calculated by comparing the result with the initial state.

[0027] Table 2. Scratch propagation suppression and impedance boosting performance test table

[0028] Based on the existing data, the scratch width of Examples 1-3 changed little during the entire 30-day test period, and the increase in the radius of expansion Δr was significantly lower than that of Comparative Examples 1 and 2. At the same time, |Z| was 0 at 30 days. 01 The Hz impedance value was significantly improved, far exceeding that of the comparative example, indicating that the protective layer maintains excellent barrier performance and corrosion inhibition capability even under long-term exposure. The overall results demonstrate that the formulation in this example exhibits significant advantages in inhibiting scratch propagation and improving corrosion resistance.

[0029] 3. Peel / Adhesion Retention Test The adhesion between the coating and the base fabric was tested using the pull-out method (ASTM D4541 or GB / T 5210) before and 30 days after slurry circulation. A 20 mm diameter pull-out head was adhered to the coating surface with high-strength adhesive. After curing for 24 h at 23 ± 2℃ and 50 ± 5% RH, the pull-out test was performed. The maximum pull-out force was recorded and converted into adhesion strength. The attenuation rate before and after circulation was compared to evaluate whether the formation of the deposited layer caused the coating to lose adhesion.

[0030] Table 3. Scratch Self-Healing and Propagation Inhibition Performance Test Table

[0031] The adhesion retention test results showed that Examples 1-3 maintained 92.5%-95.6% adhesion after 30 days of cycling, with a decay rate of less than 10%, demonstrating stable performance. In contrast, Comparative Examples 1 and 2 showed significant degradation. This indicates that the dual design incorporating mineral powder and phosphorus-based functional groups effectively prevents loss of adhesion caused by deposition delamination, significantly improving coating durability.

[0032] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-strength, corrosion-resistant woven bag substrate for mining, comprising polyolefin flat yarn fabric and a functional coating applied to its surface, characterized in that: The functional coating has a sandwich-partition structure, including: Outer wear-resistant barrier layer; The intermediate mineral powder coating comprises the following raw materials in parts by weight: 1-4 parts of calcite mineral powder, with a particle size of 1-3 μm; 1-4 parts of dolomite mineral powder, with a particle size of 1-3 μm; 85-95 parts of coating base material, wherein the coating base material is selected from one or more of acrylic resins, polyurethane resins, their modifiers and other film-forming resins; The inner layer contains a phosphorus-based coating, which contains 0.5-2 parts of one or more of phosphate ester functional group compounds, phosphonic acid functional group compounds, and combinations thereof, so that the surface phosphorus density is 0.30-1.20 mmol / m², and contains 0.1-0.5 parts of a crystal inhibiting agent; The substrate forms a Ca / Mg phosphate protective layer with a thickness of 5-10 μm at the interface after 30 days of slurry circulation, and the retention rate of longitudinal and latitudinal fracture strength is 95.0%-97.0%, and the Ca / P molar ratio of the protective layer is 1.5-1.

7.

2. The high-strength, corrosion-resistant woven bag substrate for mining as described in claim 1, characterized in that, In the calcite and dolomite powders, the fast-release phase powder accounts for 20-40% of the total powder mass, and the slow-release phase powder accounts for 60-80% of the total powder mass.

3. The high-strength, corrosion-resistant woven bag substrate for mining as described in claim 1, characterized in that, The coating contains 0.5-2 parts of magnetic particles and one or more fluorescently labeled inorganic fillers.

4. The high-strength, corrosion-resistant woven bag substrate for mining as described in claim 1, characterized in that, The polyolefin flat filament fabric is made of one or more of polypropylene, polyethylene and blends thereof, and has a stretch orientation ratio of 4.5-7.

0.

5. The high-strength, corrosion-resistant woven bag substrate for mining as described in claim 1, characterized in that, A maleic anhydride-grafted polypropylene undercoat is provided between the functional coating and the polyolefin flat filament fabric, with a coating amount of 0.5-2 g / m².

6. The high-strength, corrosion-resistant woven bag substrate for mining as described in claim 1, characterized in that, After 30 days of slurry circulation, the retention rate of longitudinal and latitudinal fracture strength was 95.0%-97.0%, and the thickness of the Ca / Mg phosphate protective layer formed at the interface was 5-10 μm, with a Ca / P molar ratio of 1.5-1.

7.

7. A method for preparing a high-strength, corrosion-resistant woven bag substrate for mining, wherein the substrate is as described in any one of claims 1-6, characterized in that, The steps are as follows: S1. Apply a primer coating to the surface of the polyolefin flat filament fabric and let it dry; S2. Prepare functional coating liquid by dispersing calcite ore powder and dolomite ore powder in the coating base in a certain proportion, and adding one or more introducing agents, crystal inhibitors and optional magnetic or fluorescent labeling fillers selected from phosphate ester functional group compounds and phosphonic acid functional group compounds. S3. Apply the sandwich-section structure to the base layer and dry at 60-90℃ to form a functional coating; S4. Tension setting at 120-135℃ to obtain the woven bag substrate.

8. The method for preparing a high-strength, corrosion-resistant woven bag substrate for mining according to claim 7, characterized in that, The crystal inhibiting agent is selected from one or more of organic acid salts, carboxyl-containing polymers, phosphonic acid-containing compounds, phosphate compounds, and combinations thereof.

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