Polyethylene anticorrosive adhesive tape and preparation method thereof

Abstract

The invention relates to the technical field of anti-corrosion adhesive tapes, in particular to a polyethylene anti-corrosion adhesive tape and a preparation method thereof. The adhesive tape comprises a polyethylene-based film layer, a glass fiber reinforcement layer, an adhesive layer and a tackifying layer, a polystyrene-polyethylene glycol block copolymer is innovatively used in the method, a water-oil double-response microcapsule is prepared, and then modified bentonite is embedded; meanwhile, maleic anhydride is grafted and modified with butyl rubber, rubber layer materials are subjected to multiple times of banburying, and the adhesive tape is prepared after all the layers are compounded. The adhesive tape disclosed by the invention has a plurality of advantages, and can keep good use performance in a complex use environment, and meanwhile, due to a tight cross-linked network of the adhesive layer, the cohesive force of the adhesive layer is enhanced, the mechanical property is improved, the interface adhesion between the adhesive tape and a pipeline is enhanced, and the adhesive tape is ensured not to fall off easily in the use process. The polyethylene anti-corrosion adhesive tape has a wide application prospect in the anti-corrosion field of petroleum and natural gas conveying pipelines and various metal facilities.

Description

Technical Field

[0001] The present invention relates to the technical field of anticorrosive tapes, and particularly to a polyethylene anticorrosive tape and a preparation method thereof. Background Art

[0002] In the current technical field of anticorrosive tapes, polyethylene anticorrosive tapes have become key materials in the anticorrosive protection of oil and gas transmission pipelines and various metal facilities due to their excellent comprehensive performance and are widely used. However, with the booming development of industry, the performance requirements for anticorrosive tapes in various engineering projects are constantly increasing, and the application scenarios have become increasingly complex and diverse. In such a general environment, a series of problems that urgently need to be solved have gradually emerged in the performance of existing polyethylene anticorrosive tapes, making it difficult to meet the increasingly stringent requirements in practical applications.

[0003] In oil and gas transmission pipelines, various substances such as moisture, long-chain alkanes, and olefins will seep out. Moisture will cause the adhesive layer of the tape to absorb water and swell, changing the physical properties of the adhesive layer and resulting in a decrease in its adhesion to the pipeline. Organic substances such as long-chain alkanes and olefins have strong solubility, and they may dissolve or swell the adhesive layer material of the tape, destroying the internal structure of the adhesive layer, and thus affecting the adhesion effect between the tape and the pipeline. For example, long-chain alkanes can penetrate between the polymer chains of the adhesive layer, weakening the intermolecular forces between the molecular chains, making the adhesive layer soft and sticky, not only reducing the adhesion between the tape and the pipeline, but also possibly causing the tape to slip on the surface of the pipeline. Under the combined action of these factors, the adhesion between the tape and the pipeline will gradually decrease, and finally the tape will fall off. Once the tape falls off, the pipeline loses effective protection and is directly exposed to the external corrosion environment, accelerating the corrosion rate of the pipeline, increasing the risk of pipeline leakage and damage, not only causing energy waste and environmental pollution, but also possibly triggering safety accidents, seriously affecting the normal progress of industrial production and the service life of facilities.

[0004] Therefore, it is extremely urgent to develop a polyethylene anticorrosive tape that can effectively resist the influence of environmental factors and substances seeping out of the pipeline and maintain good adhesion performance. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a polyethylene anticorrosive tape and a preparation method thereof to solve the problem of insufficient adhesion of existing polyethylene anticorrosive tapes after use, and at the same time have good corrosion resistance and peel strength.

[0006] Based on the above purpose, the present invention provides a polyethylene anticorrosive tape, which includes a polyethylene base film layer, a glass fiber reinforcement layer, an adhesive layer, and a tackifier layer;

[0007] The polyethylene base film layer is a polyethylene film, and a transition layer of maleic anhydride grafted polyethylene is coated on one side of the polyethylene film;

[0008] The adhesive layer is made of modified butyl rubber, styrene-butadiene rubber, EVA, polyisobutylene, silane coupling agent, graphene composite agent and antioxidant according to a weight ratio of 1:0.3 - 0.5:0.3 - 0.5:1 - 1.2:0.01 - 0.05:0.03 - 0.07:0.005 - 0.01. The preparation method of the modified butyl rubber is as follows: In a kneader, add butyl rubber, maleic anhydride, sodium hydride and antioxidant, heat up to 90 - 110°C, knead for 30 - 50 min, and obtain the modified butyl rubber after cooling to room temperature;

[0009] The tackifying layer is made by spraying a microcapsule suspension on the adhesive layer. The preparation method of the microcapsules is as follows:

[0010] (1) Crush bentonite and pass it through a 100 - 200 mesh sieve, then put it into a crucible, place it in a muffle furnace, heat it up to 550 - 650°C at a rate of 5 - 10°C / min, keep it for 3 - 5 h, and obtain thermally modified bentonite after natural cooling; Then add the thermally modified bentonite to a cetyltrimethylammonium bromide solution, react at 50 - 70°C for 6 - 12 h, after the reaction, centrifuge, wash, dry, and then grind and pass it through a 1000 - 2000 mesh sieve to obtain the modified bentonite;

[0011] (2) Add polystyrene - polyethylene glycol block copolymer to chloroform, stir for 30 - 50 min to make an oil phase; Add the modified bentonite in step (1) to deionized water, stir for 30 - 50 min to make an aqueous phase; Mix the oil phase and the aqueous phase, stir ultrasonically for 1 - 3 h, and prepare microcapsules by spray drying technology. The spray drying technology parameters include a nozzle diameter of 90 - 110 μm, an inlet temperature of drying air of 100 - 120°C, an outlet temperature of 40 - 50°C, a hot air flow rate controlled at 200 - 220 L / min, and a feeding speed of 15 - 25 ml / min.

[0012] Preferably, the thickness of the transition layer coated with maleic anhydride - grafted polyethylene is 0.05 - 0.1 mm. The addition of the transition layer makes the glass fiber layer and the polyethylene film combine more firmly, and during use, the reinforcing effect of the glass fiber can be better exerted.

[0013] Preferably, the silane coupling agent refers to KH - 550 or KH - 560. During the preparation of the glass fiber layer and the adhesive layer, the silane coupling agent forms a chemical bond connection between the glass fiber and the adhesive layer, greatly enhancing the interfacial adhesion between the two, effectively transmitting stress, and improving the overall mechanical properties of the tape.

[0014] Preferably, the graphene composite is made by compounding graphene oxide, calcium carbonate, and carbon black in a weight ratio of 2-4:3-5:1-3, which can enhance the mechanical properties of the tape, improve the anti-corrosion performance, endow it with electrical conductivity, and avoid static electricity hazards in special scenarios.

[0015] Preferably, the antioxidant refers to antioxidant 1010 or antioxidant 168.

[0016] Preferably, in the preparation method of the modified butyl rubber, the weight ratio of butyl rubber, maleic anhydride, sodium hydride, and antioxidant is 1:0.1-0.2:0.1-0.2:0.005-0.01. After being modified by maleic anhydride, the butyl rubber has new chemical activity. When mixed with components such as styrene-butadiene rubber, EVA, and polyisobutylene, more chemical bonds or stronger physical entanglements are formed between the butyl rubber and other components, thereby constructing a denser cross-linked network and showing excellent mechanical properties.

[0017] Preferably, in the preparation method of the modified butyl rubber, the antioxidant refers to antioxidant 4020.

[0018] Preferably, in (1), the weight ratio of cetyltrimethylammonium bromide solution to thermally modified bentonite is 3-5:0.8-1.2. After being intercalated and modified by cetyltrimethylammonium bromide, the interlayer spacing of the bentonite becomes larger, and it has a greater adsorption capacity when adsorbing pollutants.

[0019] Preferably, in (1), the concentration of the cetyltrimethylammonium bromide solution is 0.3-0.5 mol / L.

[0020] Preferably, in (2), the weight ratio of polystyrene-polyethylene glycol block copolymer, chloroform, modified bentonite, and deionized water is 10-15:100:20-45:200-300. The polystyrene-polyethylene glycol block copolymer, as the wall material of the microcapsule, provides the water-oil dual-responsive function of the microcapsule, and can make better release choices when facing a complex environment, improving the use efficiency of the microcapsule.

[0021] Furthermore, the present invention also provides a preparation method of the above-mentioned polyethylene anti-corrosion tape, which specifically includes the following steps:

[0022] S1. Put the modified butyl rubber and styrene-butadiene rubber into a mixer, knead at 130-145 °C for 30-40 min, then add EVA, polyisobutylene, and a cross-linking agent and knead for 50-70 min. Finally, add the graphene composite and antioxidant and knead for 20-30 min, and then extrude in an extruder to obtain the adhesive layer material;

[0023] S2. Coat one side of the polyethylene film with a maleic anhydride-grafted polyethylene transition layer. After pre-softening at 80 - 100 °C, lay the glass fiber flat on the transition layer, apply a pressure of 0.5 - 1 MPa, hold the pressure for 10 - 20 s to obtain a glass fiber layer with a thickness of 0.2 - 0.5 mm. Then, coat the adhesive layer material obtained in S1 on the glass fiber layer through an automatic coater with a thickness of 0.5 - 1 mm, and compound it at 80 - 120 °C through a double-roll calender. Finally, make the microcapsules into a suspension and evenly coat it on the adhesive layer with a spraying density of 50 - 70 g / ㎡ based on the weight of the microcapsules. After drying, curing, cutting, and winding, a polyethylene anti-corrosion tape is obtained.

[0024] Advantages of the present invention:

[0025] 1. The water-oil dual-responsive microcapsules enhance the protection performance: The water-oil dual-responsive microcapsules prepared in the present invention exhibit excellent environmental adaptability. The microcapsule wall material uses a specific polystyrene-polyethylene glycol block copolymer, which endows the microcapsules with unique water-oil dual-responsive characteristics. When moisture or oily pollutants appear in the environment where the tape is located, the microcapsules can release the core material in a timely manner. The modified bentonite in the core material can adsorb these pollutants, reduce their erosion of the adhesive layer, thereby effectively enhancing the corrosion resistance of the tape and extending the service life of the tape in a complex environment.

[0026] 2. The microcapsule adsorption enhances the tape adhesion: The modified bentonite in the microcapsules has special adsorption and viscosity-increasing properties. During the use of the tape, when moisture or oil seeps out from the pipeline, the modified bentonite, relying on its large specific surface area and special microstructure, quickly adsorbs these substances. During the adsorption process, the modified bentonite itself undergoes a physical change and becomes sticky. This increase in viscosity plays a key role between the tape and the pipeline. It is like an "extra glue", enhancing the adhesion force between the tape and the pipeline surface. Even under the long-term influence of the exudates in the pipeline, the tape can still firmly adhere to the pipeline, greatly improving the practicality and reliability of the tape, ensuring the continuous and effective protection of the tape for the pipeline, reducing the risk of tape detachment, and providing a more reliable guarantee for pipeline anti-corrosion.

[0027] 3. Optimization of Tape Performance by Maleic Anhydride Grafted Butyl Rubber: Maleic anhydride grafted butyl rubber optimizes the performance of the tape from multiple dimensions. The polar groups introduced during the grafting process bring new chemical activities to butyl rubber. When mixed with components such as styrene-butadiene rubber, EVA, and polyisobutylene, these polar groups promote the formation of more chemical bonds or stronger physical entanglements between butyl rubber and other components, thereby constructing a denser crosslinked network. This crosslinked network significantly enhances the cohesion of the adhesive layer, enabling the tape to maintain its structural integrity when subjected to external forces such as tension and extrusion, and demonstrating more excellent mechanical properties. At the same time, the presence of polar groups also enhances the interfacial adhesion between the tape and the pipeline, enabling the tape to fit more closely to the pipeline surface, effectively resisting the negative impact of external environmental factors on the adhesion performance of the tape, comprehensively improving the anti-corrosion performance of the tape, and ensuring the stable operation of the tape in complex environments. Brief Description of the Drawings

[0028] Figure 1 Bar chart of the peel strength test data of the polyethylene anti-corrosion tape prepared in Examples 1-3 and Comparative Examples 1-4 on steel, back film, and the pipe after use. Detailed Description of the Invention

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the following further elaborates on the present invention with reference to specific embodiments.

[0030] The sources of the reagent raw materials used in the embodiments of the present invention are as follows:

[0031] Bentonite was purchased from Shanghai Macklin Biochemical Co., Ltd., product number B802109; cetyltrimethylammonium bromide was purchased from Shanghai Macklin Biochemical Co., Ltd., product number H811115; polystyrene-polyethylene glycol block copolymer was purchased from Guangzhou Weihua Biotechnology Co., Ltd., purity 95%; butyl rubber was purchased from Shanghai Sigma-Aldrich Biotechnology Co., Ltd., 2.2 mol.% unsaturation, Mw 500,000; maleic anhydride was purchased from Shanghai Macklin Biochemical Co., Ltd., product number M813920, purity 99%; sodium hydride was purchased from Shanghai Macklin Biochemical Co., Ltd., product number S817935, 60% dispersion in mineral oil; antioxidant 4020 was purchased from Shanghai Macklin Biochemical Co., Ltd., product number N858057, purity 98%; antioxidant 1010 was purchased from Shanghai Macklin Biochemical Co., Ltd., product number P829612, purity 94%; EVA was purchased from Shanghai Macklin Biochemical Co., Ltd., product number P815473; polyisobutylene was purchased from Shanghai Macklin Biochemical Co., Ltd., product number P799383, Mw 425,000; styrene-butadiene rubber was purchased from Shanghai Macklin Biochemical Co., Ltd., product number B768465, Mw 140,000; KH-550 was purchased from Shanghai Macklin Biochemical Co., Ltd., product number A800523, purity 99%; graphene oxide was purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd., product number 900704; calcium carbonate was purchased from Shanghai Macklin Biochemical Co., Ltd., product number C805317, purity 99%; carbon black was purchased from Shanghai Macklin Biochemical Co., Ltd., product number C824455; polyethylene film was purchased from Changzhou Kaide New Materials Technology Co., Ltd.; maleic anhydride grafted polyethylene was purchased from Shanghai Macklin Biochemical Co., Ltd., product number P875047, grafting rate 8%; glass fiber was purchased from Wuxi Fushi De High-tech Materials Manufacturing Co., Ltd., models EWR200-100, EWR300-100, EWR500-100; polyethylene glycol was purchased from Shanghai Macklin Biochemical Co., Ltd., product number P766664, Mw 5000.

[0032] Example 1: A specific preparation method of a polyethylene anticorrosive tape, including the following process:

[0033] (1) After crushing 120 g of bentonite through a 100-mesh sieve, it was placed in a crucible and heated in a muffle furnace to 550 °C at a rate of 5 °C / min, maintained for 3 h, and naturally cooled to obtain thermally modified bentonite; then 100 g of thermally modified bentonite was added to 450 g of a 0.3 mol / L cetyltrimethylammonium bromide solution and reacted at 50 °C for 6 h. After the reaction, it was centrifuged, washed, dried, and then ground through a 1000-mesh sieve to obtain modified bentonite;

[0034] (2) Add 50 g of polystyrene - polyethylene glycol block copolymer to 500 g of chloroform and stir for 30 min to prepare the oil phase; add 100 g of the modified bentonite in step (1) to 1 L of deionized water and stir for 30 min to prepare the water phase; mix the oil phase and the water phase, and carry out ultrasonic stirring for 1 h. Microcapsules are prepared by spray drying technology, where the spray drying technology parameters include a nozzle diameter of 90 μm, an inlet temperature of drying air of 100 °C, an outlet temperature of 40 °C, a hot air flow rate controlled at 200 L / min, and a feeding rate of 15 ml / min;

[0035] (3) In a mixer, add 550 g of butyl rubber, 55 g of maleic anhydride, 55 g of sodium hydride, and 2.75 g of antioxidant 4020, heat up to 90 °C, and carry out mixing for 30 min. After cooling to room temperature, modified butyl rubber is obtained;

[0036] (4) Put 500 g of modified butyl rubber and 150 g of styrene - butadiene rubber into a mixer, carry out mixing at 130 °C for 30 min, then add 150 g of EVA, 500 g of polyisobutylene, and 5 g of KH - 550 and mix for 50 min. Finally, add 15 g of graphene composite agent (graphene oxide: calcium carbonate: carbon black = 2:3:1) and 0.5 g of antioxidant 1010, mix for 20 min, and then extrude in an extruder to obtain the adhesive layer material;

[0037] (5) Coat a polyethylene transition layer grafted with maleic anhydride with a thickness of 0.05 mm on the surface of the polyethylene film. After pre - softening at 80 °C, lay the glass fiber EWR200 - 100 flat on the transition layer, apply a pressure of 0.5 MPa, and keep the pressure for 10 s to obtain a glass fiber layer with a thickness of 0.2 mm. Then, coat the adhesive layer material obtained in step (4) on the glass fiber layer through an automatic coater with a thickness of 0.5 mm, and carry out lamination at 80 °C through a two - roll calender to obtain the adhesive layer. Finally, make the microcapsules obtained in step (2) into a suspension, and evenly coat it on the adhesive layer with a spraying density of 50 g / ㎡ based on the weight of the microcapsules. After drying, curing, cutting, and winding, the polyethylene anticorrosive tape is obtained.

[0038] Example 2: A specific preparation method of a polyethylene anticorrosive tape, including the following process:

[0039] (1) Crush 120 g of bentonite, pass it through a 150 - mesh sieve, put it into a crucible, place it in a muffle furnace, heat it to 600 °C at a rate of 7 °C / min, keep it for 4 h, and then naturally cool to obtain thermally modified bentonite; then add 100 g of thermally modified bentonite to 400 g of a 0.4 mol / L cetyltrimethylammonium bromide solution, react at 60 °C for 9 h. After the reaction, centrifuge, wash, dry, and then grind it through a 1500 - mesh sieve to obtain the modified bentonite;

[0040] (2) Add 40 g of polystyrene-polyethylene glycol block copolymer to 350 g of chloroform and stir for 40 min to prepare an oil phase; add 100 g of modified bentonite from step (1) to 830 g of deionized water and stir for 40 min to prepare an aqueous phase; mix the oil phase and the aqueous phase, and perform ultrasonic stirring for 2 h. Microcapsules are prepared by spray drying technology, and the spray drying technology parameters include a nozzle diameter of 100 μm, an inlet temperature of drying air of 110 °C, an outlet temperature of 45 °C, a hot air flow rate controlled at 210 L / min, and a feeding rate of 20 ml / min;

[0041] (3) In a mixer, add 550 g of butyl rubber, 82 g of maleic anhydride, 82 g of sodium hydride, and 3.85 g of antioxidant 4020, heat up to 100 °C, mix for 40 min, and obtain modified butyl rubber after cooling to room temperature;

[0042] (4) Put 500 g of modified butyl rubber and 200 g of styrene-butadiene rubber into a mixer, mix at 140 °C for 35 min, then add 200 g of EVA, 550 g of polyisobutylene, and 15 g of KH-550 and mix for 60 min. Finally, add 3.5 g of 25 g of graphene composite agent (graphene oxide: calcium carbonate: carbon black = 3:4:2) and antioxidant 1010 and mix for 25 min, and then extrude in an extruder to obtain a rubber layer material;

[0043] (5) Coat a polyethylene transition layer grafted with maleic anhydride with a thickness of 0.07 mm on the surface of the polyethylene film. After pre-softening at 90 °C, lay the glass fiber EWR300-100 flat on the transition layer, apply a pressure of 0.7 MPa, and keep the pressure for 15 s to obtain a glass fiber layer with a thickness of 0.3 mm. Then, coat the rubber layer material obtained in step (4) on the glass fiber layer through an automatic coater with a thickness of 0.7 mm, and compound at 100 °C through a two-roll calender to obtain a rubber layer. Finally, make the microcapsules obtained in step (2) into a suspension, and evenly coat it on the rubber layer with a spray gun. The spraying density is 60 g / ㎡ based on the weight of the microcapsules. After drying, curing, cutting, and winding, a polyethylene anti-corrosion tape is obtained.

[0044] Example 3: A specific preparation method of a polyethylene anti-corrosion tape, including the following process:

[0045] (1) Crush 120 g of bentonite through a 200-mesh sieve and put it into a crucible. Place it in a muffle furnace and heat it to 650 °C at a rate of 10 °C / min, keep it for 5 hours, and obtain thermally modified bentonite after natural cooling; then add 96 g of thermally modified bentonite to 400 g of a 0.5 mol / L cetyltrimethylammonium bromide solution, react at 70 °C for 12 h. After the reaction, centrifuge, wash, dry, and then grind through a 2000-mesh sieve to obtain modified bentonite;

[0046] (2) Add 30 g of polystyrene - polyethylene glycol block copolymer to 200 g of chloroform and stir for 50 min to prepare the oil phase; add 90 g of modified bentonite in step (1) to 600 g of deionized water and stir for 50 min to prepare the water phase; mix the oil phase and the water phase, and perform ultrasonic stirring for 3 h. Microcapsules are prepared by spray drying technology, where the spray drying technology parameters include a nozzle diameter of 110 μm, an inlet temperature of the drying air of 120 °C, an outlet temperature of 50 °C, a hot air flow rate controlled at 220 L / min, and a feeding speed of 25 ml / min;

[0047] (3) In a mixer, add 550 g of butyl rubber, 110 g of maleic anhydride, 110 g of sodium hydride, and 5.5 g of antioxidant 4020, heat up to 110 °C, and perform mixing for 50 min. After cooling to room temperature, modified butyl rubber is obtained;

[0048] (4) Put 500 g of modified butyl rubber and 250 g of styrene - butadiene rubber into a mixer, perform mixing at 145 °C for 30 - 40 min, then add 250 g of EVA, 600 g of polyisobutylene, and 25 g of KH - 550 and mix for 70 min. Finally, add 35 g of graphene composite agent (graphene oxide:calcium carbonate:carbon black = 4:5:3) and 5 g of antioxidant 1010, mix for 30 min, and then extrude in an extruder to obtain the adhesive layer material;

[0049] (5) Coating a layer of maleic anhydride - grafted polyethylene transition layer with a thickness of 0.1 mm on the surface of the polyethylene film. After pre - softening at 100 °C, lay the glass fiber EWR500 - 100 flat on the transition layer, apply a pressure of 1 MPa, and keep the pressure for 20 s to obtain a glass fiber layer with a thickness of 0.5 mm. Then, coat the adhesive layer material obtained in step (4) on the glass fiber layer through an automatic coater with a thickness of 1 mm, and perform lamination at 120 °C through a two - roll calender to obtain the adhesive layer. Finally, prepare the microcapsules obtained in step (2) into a suspension, and evenly coat it on the adhesive layer with a spraying density of 70 g / ㎡ based on the weight of the microcapsules. After drying, curing, cutting, and winding, the polyethylene anticorrosive tape is obtained.

[0050] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that the modified bentonite is replaced with ordinary unmodified bentonite. The specific preparation process is as follows: A specific preparation method of a polyethylene anticorrosive tape includes the following process:

[0051] (1) 40 g of polystyrene - polyethylene glycol block copolymer was added to 350 g of chloroform and stirred for 40 min to prepare an oil phase; 100 g of bentonite was added to 830 g of deionized water and stirred for 40 min to prepare an aqueous phase; the oil phase and the aqueous phase were mixed and ultrasonically stirred for 2 h, and microcapsules were prepared by spray drying technology. The spray drying technology parameters included a nozzle diameter of 100 μm, an inlet temperature of drying air of 110 °C, an outlet temperature of 45 °C, a hot air flow rate controlled at 210 L / min, and a feeding rate of 20 ml / min;

[0052] (2) In a mixer, 550 g of butyl rubber, 82 g of maleic anhydride, 82 g of sodium hydride, and 3.85 g of antioxidant 4020 were added, heated to 100 °C, and kneaded for 40 min. After cooling to room temperature, modified butyl rubber was obtained;

[0053] (3) 500 g of modified butyl rubber and 200 g of styrene - butadiene rubber were put into a mixer, kneaded at 140 °C for 35 min, then 200 g of EVA, 550 g of polyisobutylene, and 15 g of KH - 550 were added and kneaded for 60 min. Finally, 3.5 g of antioxidant 1010 and 25 g of graphene composite agent (graphene oxide: calcium carbonate: carbon black = 3:4:2) were added and kneaded for 25 min, and then extruded in an extruder to obtain a rubber layer material;

[0054] (4) A polyethylene transition layer grafted with maleic anhydride with a thickness of 0.07 mm was coated on the surface of the polyethylene film. After pre - softening at 90 °C, glass fiber EWR300 - 100 was laid flat on the transition layer, and a pressure of 0.7 MPa was applied and held for 15 s to obtain a glass fiber layer with a thickness of 0.3 mm. Finally, the rubber layer material obtained in step (3) was coated on the glass fiber layer by an automatic coater with a thickness of 0.7 mm, and compounded at 100 °C by a two - roll calender to obtain a rubber layer. Finally, the microcapsules obtained in step (1) were made into a suspension, and evenly coated on the rubber layer by a spray gun. The spraying density was 60 g / ㎡ based on the weight of the microcapsules. After drying, curing, cutting, and winding, a polyethylene anticorrosive tape was obtained.

[0055] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that the polystyrene - polyethylene glycol block copolymer was replaced by polyethylene glycol. The specific preparation process is as follows: A specific preparation method of a polyethylene anticorrosive tape includes the following process:

[0056] (1) Crush 120 g of bentonite, sieve it through a 150-mesh sieve, put it into a crucible, place it in a muffle furnace, heat it to 600 °C at a rate of 7 °C / min, keep it for 4 h, and let it cool naturally to obtain thermally modified bentonite; then add 100 g of thermally modified bentonite to 400 g of a cetyltrimethylammonium bromide solution with a concentration of 0.4 mol / L, react at 60 °C for 9 h, after the reaction, centrifuge, wash, dry, and then grind it through a 1500-mesh sieve to obtain modified bentonite;

[0057] (2) Add 40 g of polyethylene glycol to 700 g of deionized water, stir for 40 min to prepare an aqueous phase; add 100 g of the modified bentonite in step (1) to the aqueous phase, and emulsify it in a high-speed shear emulsifier at a rotation speed of 8000 r / min for 30 min. Microcapsules are prepared by spray drying technology, and the spray drying technology parameters include a nozzle diameter of 100 μm, an inlet temperature of drying air of 110 °C, an outlet temperature of 45 °C, a hot air flow rate controlled at 210 L / min, and a feeding speed of 20 ml / min;

[0058] (3) In a mixer, add 550 g of butyl rubber, 82 g of maleic anhydride, 82 g of sodium hydride, and 3.85 g of antioxidant 4020, heat it to 100 °C, mix for 40 min, and cool to room temperature to obtain modified butyl rubber;

[0059] (4) Put 500 g of modified butyl rubber and 200 g of styrene-butadiene rubber into a mixer, mix at 140 °C for 35 min, then add 200 g of EVA, 550 g of polyisobutylene, and 15 g of KH-550 and mix for 60 min. Finally, add 3.5 g of antioxidant 1010 and 25 g of graphene composite agent (graphene oxide: calcium carbonate: carbon black = 3:4:2) and mix for 25 min, and then extrude it in an extruder to obtain a rubber layer material;

[0060] (5) Coating a layer of maleic anhydride-grafted polyethylene transition layer with a thickness of 0.07 mm on the surface of the polyethylene film, after pre-softening at 90 °C, lay the glass fiber EWR300-100 flat on the transition layer, apply a pressure of 0.7 MPa, and keep the pressure for 15 s to obtain a glass fiber layer with a thickness of 0.3 mm. Then, coat the rubber layer material obtained in step (4) on the glass fiber layer through an automatic coater with a thickness of 0.7 mm, and compound it at 100 °C through a two-roll calender to obtain a rubber layer. Finally, make the microcapsules obtained in step (2) into a suspension, and evenly coat it on the rubber layer with a spray gun. The spraying density is 60 g / ㎡ based on the weight of the microcapsules. After drying, curing, cutting, and winding, a polyethylene anticorrosive tape is obtained.

[0061] Comparative Example 3: The difference between Comparative Example 3 and Example 2 is that microcapsule-encapsulated modified bentonite is not added. The specific preparation process is as follows: A specific preparation method of a polyethylene anticorrosive tape includes the following process:

[0062] (1) In a Banbury mixer, 550 g of butyl rubber, 82 g of maleic anhydride, 82 g of sodium hydride and 3.85 g of antioxidant 4020 were added. The temperature was raised to 100 °C and kneaded for 40 min. After cooling to room temperature, modified butyl rubber was obtained.

[0063] (2) 500 g of modified butyl rubber and 200 g of styrene-butadiene rubber were put into a Banbury mixer and kneaded at 140 °C for 35 min. Then, 200 g of EVA, 550 g of polyisobutylene and 15 g of KH-550 were added and kneaded for 60 min. Finally, 3.5 g of antioxidant 1010 and 25 g of graphene composite agent (graphene oxide: calcium carbonate: carbon black = 3:4:2) were kneaded for 25 min and then extruded in an extruder to obtain a rubber layer material.

[0064] (3) A polyethylene transition layer grafted with maleic anhydride with a thickness of 0.07 mm was coated on the surface of a polyethylene film. After pre-softening at 90 °C, EWR300-100 glass fiber was laid flat on the transition layer, and a pressure of 0.7 MPa was applied and kept for 15 s to obtain a glass fiber layer with a thickness of 0.3 mm. Then, the rubber layer material obtained in step (4) was coated on the glass fiber layer by an automatic coater with a thickness of 0.7 mm and compounded at 100 °C by a two-roll calender. After cutting and winding, a polyethylene anticorrosive tape was obtained.

[0065] Comparative Example 4: The difference between Comparative Example 4 and Example 2 is that the butyl rubber is not grafted with maleic anhydride. The specific preparation process is as follows: A specific preparation method of a polyethylene anticorrosive tape includes the following process:

[0066] (1) 120 g of bentonite was crushed and passed through a 150-mesh sieve and then put into a crucible. It was placed in a muffle furnace and heated to 600 °C at a rate of 7 °C / min and kept for 4 h. After natural cooling, heat-modified bentonite was obtained. Then, 100 g of heat-modified bentonite was added to 400 g of a 0.4 mol / L cetyltrimethylammonium bromide solution and reacted at 60 °C for 9 h. After the reaction, it was centrifuged, washed, dried, and then ground and passed through a 1500-mesh sieve to obtain modified bentonite.

[0067] (2) 40 g of polystyrene-polyethylene glycol block copolymer was added to 350 g of chloroform and stirred for 40 min to prepare an oil phase. 100 g of the modified bentonite obtained in step (1) was added to 830 g of deionized water and stirred for 40 min to prepare an aqueous phase. The oil phase and the aqueous phase were mixed and ultrasonically stirred for 2 h. Microcapsules were prepared by spray drying technology. The spray drying technology parameters included a nozzle diameter of 100 μm, an inlet temperature of the drying air of 110 °C, an outlet temperature of 45 °C, a hot air flow rate controlled at 210 L / min, and a feeding rate of 20 ml / min.

[0068] (3) Put 500 g of butyl rubber and 200 g of styrene-butadiene rubber into a Banbury mixer, mix at 140 °C for 35 min, then add 200 g of EVA, 550 g of polyisobutylene and 15 g of KH-550 and mix for 60 min. Finally, add 25 g of graphene composite agent (graphene oxide: calcium carbonate: carbon black = 3:4:2) and 3.5 g of antioxidant 1010, mix for 25 min and then extrude in an extruder to obtain the adhesive layer material;

[0069] (4) Coat a polyethylene transition layer grafted with maleic anhydride with a thickness of 0.07 mm on the surface of the polyethylene film. After pre-softening at 90 °C, lay the EWR300-100 glass fiber flat on the transition layer, apply a pressure of 0.7 MPa, and keep the pressure for 15 s to obtain a glass fiber layer with a thickness of 0.3 mm. Then, coat the adhesive layer material obtained in step (4) on the glass fiber layer through an automatic coater with a thickness of 0.7 mm, and compound it at 100 °C through a two-roll calender to obtain the adhesive layer. Finally, make the microcapsules obtained in step (2) into a suspension, and evenly coat it on the adhesive layer with a spray gun. The spraying density is 60 g / ㎡ based on the weight of the microcapsules. After drying, curing, cutting, and winding, the polyethylene anti-corrosion tape is obtained.

[0070] Performance test:

[0071] Prepare the polyethylene anti-corrosion tapes with the same size according to the preparation methods in Examples 1-3 and Comparative Examples 1-4 respectively as test samples.

[0072] 1. Tape thickness test: Conduct the test according to the conditions specified in Standard GB / T 6672-2001. The experimental data are shown in Table 1.

[0073] 2. Tensile strength test: Conduct the test according to Standard GB / T 1040.3-2006. The experimental results are shown in Table 1.

[0074] 3. Chemical corrosion resistance test: Conduct the test according to SY / T0315-2013. Test the chemical corrosion resistance of the tape in dilute hydrochloric acid, 10% sodium chloride aqueous solution, and 5% sodium hydroxide aqueous solution. After the test, observe the appearance and test the peel strength of the tape on the test piece. The experimental results are shown in Table 1.

[0075] 4. Peel strength test: Conduct the test according to Standard GB / T 2792-2014. Test the peel strength of the tape on steel and the back film respectively. The experimental results are as Figure 1 shown.

[0076] 5. Peel strength test after use: Wrap the tape around the underground oil pipeline to simulate the exudates that may be encountered in the daily use environment, including but not limited to moisture, various long-chain alkanes, olefins, etc. After 180 days of testing, then conduct the test according to GB / T 2792-2014 to test the peel strength of the tape on the pipeline. The experimental results are as Figure 1 shown.

[0077] Table 1

[0078]

[0079] Data analysis:

[0080] It can be seen from the data of Examples 1-3 in the experiment that the polyethylene anticorrosive tapes prepared in Examples 1-3 all exhibit excellent mechanical properties and good chemical corrosion resistance, especially better peel strength after use. This shows that during the use of the tape, it will not become easy to fall off due to the exudates in the pipeline or the external environment. Instead, the bonding performance may be even better.

[0081] It can be seen from the experimental data of Example 2 and Comparative Example 1 that the performance of Comparative Example 1 decreased compared with Example 2. This may be because the bentonite was not modified and had strong surface hydrophilicity, so it could not be well integrated with the wall material during the preparation of the microcapsules, resulting in inconsistent microcapsule shapes and poor dispersion, affecting the tensile strength and peel strength of the tape. At the same time, the smaller layer spacing also led to a decrease in adsorption capacity, resulting in moisture and oil in the use process being more likely to directly contact the adhesive layer, damaging the adhesive layer structure and causing problems such as bulging, resulting in a decrease in the peel strength after use.

[0082] It can be seen from the experimental data of Example 2 and Comparative Example 2 that there is a large gap between Comparative Example 2 and Example 2 in terms of acid and alkali corrosion resistance and peel strength after use. This may be because the lack of the water-oil dual-responsive mechanism brought by the polystyrene-polyethylene glycol block copolymer makes it impossible to release the core material in the microcapsules in time to reduce the damage of pollutants to the adhesive layer material when facing the complex situations in the use environment. Polyethylene glycol can only release the core material when facing water-based pollutants. Once the pollutants are oil-based pollutants, the microcapsules will lose their function, resulting in a decrease in the peel strength of the tape and affecting the service life of the tape. At the same time, when facing acid and alkali corrosion, the microcapsules prepared by polyethylene glycol dissolve and release the core material too quickly, and the core material has not had time to adsorb and become sticky. The relatively large amount of swollen core material causes a large roughness of the adhesive layer, and the acid-base solution is easy to enter the adhesive layer, affecting the acid-base tolerance of the tape.

[0083] It can be seen from the experimental data of Example 2 and Comparative Example 3 that although the various performances of Comparative Example 3 are close to those of Example 2, there is a huge decrease in the peel strength after use. This may be because in actual use, substances such as moisture, long-chain alkanes, and olefins will seep out from underground oil pipelines. In Example 2, the microcapsule-coated modified bentonite has a large specific surface area and a special layered structure, which can effectively adsorb these seeped substances. However, Comparative Example 3 lacks this key component, and the seeped pollutants can directly contact the adhesive layer material. Moisture will cause the adhesive layer to absorb water and swell, damaging the bonding interface between the adhesive layer and the pipeline, fiberglass layer, etc.; organic substances such as long-chain alkanes and olefins may dissolve or swell components such as rubber in the adhesive layer, changing the physical and chemical properties of the adhesive layer, reducing the cohesion of the adhesive layer and the adhesion to other materials. These destructive effects lead to serious damage to the structure of the adhesive layer. At the same time, after the modified bentonite adsorbs moisture and oil, it will become sticky, forming an additional sticky connection between the adhesive layer and the pipeline, enhancing the adhesion effect between the tape and the pipeline. However, in Comparative Example 3, this adsorption and viscosity-increasing effect cannot be generated. When subjected to external forces, the connection between the adhesive layer and the pipeline is weak and prone to peeling, resulting in a significant decrease in the peel strength after use, seriously affecting the performance and stability of the tape in practical applications.

[0084] It can be seen from the experimental data of Example 2 and Comparative Example 4 that maleic anhydride-grafted butyl rubber is very helpful for improving the performance of the tape. This may be because maleic anhydride-grafted butyl rubber can introduce polar groups, which helps the butyl rubber form a more compact crosslinked network in the adhesive layer. The grafted butyl rubber can interact better with styrene-butadiene rubber, EVA, polyisobutylene, etc., forming a stable three-dimensional network structure through chemical bonds or physical entanglements, enhancing the cohesion of the adhesive layer, making the materials combine more tightly, making it difficult for pollutants such as moisture and oil to enter between the adhesive layers, greatly inhibiting the damage of the materials, and at the same time enhancing the interfacial adhesion between the tape and the pipeline, thereby improving the peel strength of the tape. In Comparative Example 4, since the butyl rubber is not grafted, the degree of crosslinking reaction is relatively low, and a dense and stable crosslinked network like that in Example 2 cannot be formed. During long-term use, the adhesive layer is more likely to be damaged by external factors. Substances such as moisture, long-chain alkanes, and olefins seeping out from the pipeline will gradually penetrate into the interior of the adhesive layer, damaging the structure of the adhesive layer, further reducing the cohesion of the adhesive layer and the adhesion to the pipeline, resulting in a significant decrease in the peel strength after use.

[0085] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A polyethylene anti-corrosion tape, characterized in that: It includes a polyethylene-based film layer, a glass fiber reinforcement layer, a glue layer and an adhesion-enhancing layer; The polyethylene-based film layer is a polyethylene film, and a transition layer of maleic anhydride-grafted polyethylene is coated on one side of the polyethylene film; The rubber layer is made of modified butyl rubber, styrene-butadiene rubber, EVA, polyisobutylene, silane coupling agent, graphene composite agent and antioxidant in a weight ratio of 1:0.3-0.5:0.3-0.5:1-1.2:0.01-0.05:0.03-0.07:0.005-0.

01. The preparation method of the modified butyl rubber is as follows: butyl rubber, maleic anhydride, sodium hydride and antioxidant are added into an internal mixer, the temperature is raised to 90-110°C, internal mixing is performed for 30-50 minutes, and the modified butyl rubber is obtained after cooling to room temperature; The adhesion-enhancing layer is prepared by spraying a microcapsule suspension on a glue layer. The preparation method of the microcapsules is as follows: (1) crushing bentonite through a 100-200 mesh sieve, placing it in a crucible, placing it in a muffle furnace and heating it to 550-650° C. at 5-10° C. / min, maintaining it for 3-5 hours, and naturally cooling it to obtain thermally modified bentonite; then adding hexadecyltrimethylammonium bromide solution to the thermally modified bentonite, reacting it at 50-70° C. for 6-12 hours, centrifuging, washing, drying, and grinding it through a 1000-2000 mesh sieve to obtain modified bentonite; (2) adding polystyrene-polyethylene glycol block copolymer to chloroform and stirring for 30-50 minutes to prepare an oil phase; adding the modified bentonite in step (1) to deionized water and stirring for 30-50 minutes to prepare an aqueous phase; mixing the oil phase and the aqueous phase, ultrasonically stirring for 1-3 hours, and preparing microcapsules by spray drying technology, wherein the spray drying technology parameters include a nozzle diameter of 90-110 μm, a dry air inlet temperature of 100-120° C., an air outlet temperature of 40-50° C., a hot air flow rate controlled at 200-220 L / min, and a feed rate of 15-25 ml / min.

2. The polyethylene anti-corrosion tape according to claim 1, characterized in that: The thickness of the transition layer coated with a layer of maleic anhydride grafted polyethylene is 0.05-0.1 mm.

3. The polyethylene anti-corrosion tape according to claim 1, characterized in that: The silane coupling agent refers to KH-550 or KH-560.

4. The polyethylene anticorrosion tape according to claim 1, characterized in that: The graphene composite refers to graphene oxide, calcium carbonate and carbon black compounded in a weight ratio of 2-4:3-5:1-3.

5. The polyethylene anti-corrosion tape according to claim 1, characterized in that: The antioxidant refers to antioxidant 1010 or antioxidant 168.

6. The polyethylene anticorrosion tape according to claim 1, characterized in that: In the preparation method of the modified butyl rubber, the weight ratio of butyl rubber, maleic anhydride, sodium hydride and antioxidant is 1:0.1-0.2:0.1-0.2:0.005-0.

01.

7. The polyethylene anticorrosion tape according to claim 1, characterized in that: In the preparation method of the modified butyl rubber, the antioxidant refers to antioxidant 4020.

8. The polyethylene anticorrosion tape according to claim 1, characterized in that: The weight ratio of the cetyltrimethylammonium bromide solution and the thermally modified bentonite in (1) is 3-5: 0.8-1.2, the concentration of hexadecyltrimethylammonium bromide solution is 0.3-0.5mol / L.

9. The polyethylene anticorrosion tape according to claim 1, characterized in that: The weight ratio of the polystyrene-polyethylene glycol block copolymer, chloroform, modified bentonite and deionized water in (2) is 10-15:100:20-45:200-300.

10. The method for preparing the polyethylene anticorrosive tape according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. The modified butyl rubber and styrene-butadiene rubber are placed in an internal mixer, mixed at 130-145°C for 30-40min, then EVA, polyisobutylene and a crosslinking agent are added and mixed for 50-70min, and finally, a graphene composite agent and an antioxidant are added and mixed for 20-30min and then extruded in an extruder to obtain a rubber layer material; S2. Coat one side of the polyethylene film with a maleic anhydride grafted polyethylene transition layer, pre-soften it at 80-100℃, then lay the glass fiber on the transition layer, apply a pressure of 0.5-1MPa, and maintain the pressure for 10-20s to obtain a glass fiber layer with a thickness of 0.2-0.5mm. Then, use an automatic coating machine to coat the adhesive layer material obtained in S1 on the glass fiber layer with a thickness of 0.5-1mm, and compound it at 80-120℃ through a double-roll calender. Finally, make the microcapsules into a suspension and evenly coat it on the adhesive layer with a spray gun. The spraying density is 50-70g / ㎡ based on the weight of the microcapsules. After drying, curing, cutting and winding, the polyethylene anti-corrosion tape is obtained.

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