Preparation process of high-water-resistance expansion type composite strip

Abstract

The invention relates to the technical field of composite materials, and discloses a preparation process of a high-water-resistance expansion type composite strip, which comprises the following steps: pretreating a base material, selecting a polyester woven belt and a nylon woven belt as the base material with the gram weight of 80-120 g / m < 2 >, carrying out plasma cleaning and surface activation treatment on the base material, coating an expansion layer, and drying to obtain the high-water-resistance expansion type composite strip. When the high-water-resistance expansion type composite strip is prepared, the interface bonding force between the base material and the functional layer is enhanced by adopting a plasma cleaning and surface activation treatment process, and meanwhile, uniform distribution of a barrier layer impregnation liquid in the expansion layer is ensured by adopting a rolling-assisted permeation technology, so that the problems of interlayer stripping and non-uniform permeation can be effectively avoided, and the service life of the high-water-resistance expansion type composite strip is prolonged. The structural integrity and long-term sealing stability of the strip are guaranteed, the mechanical property and durability of the composite strip are further improved, the stable physical form is kept in the expansion process, and it is guaranteed that the strip can play a reliable sealing role in different application environments.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to the preparation process of high water-resistant, expandable composite strips. Background Technology

[0002] Composite materials are new materials created by combining different material components using advanced material preparation technologies.

[0003] Currently, because the production process of composite strips involves the combination of multiple materials and chemical treatment, the coating and impregnation processes used in the preparation of the water-blocking layer of the strip form a barrier layer on the surface of the substrate. It is impossible to control the interface bonding state between the barrier layer and the expansion layer in real time. When the interface bonding force is insufficient or there is excessive penetration, it will cause interlayer peeling and limited expansion performance, and the long-term sealing stability of the strip cannot be guaranteed.

[0004] Therefore, a high water-resistant, expandable composite strip manufacturing process is proposed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a process for preparing high water-resistant, expandable composite tapes, which solves the problems of interlayer peeling and limited expansion performance mentioned in the background technology, thus failing to guarantee the long-term sealing stability of the tapes.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a process for preparing high water-resistant, expandable composite strips, comprising the following steps: Step 1: Substrate pretreatment. Polyester braided tape and nylon braided tape are selected as substrates, with a substrate weight of 80-120 g / m². 2 They are subjected to plasma cleaning and surface activation treatment; Step 2: Coating the expansion layer. Apply the expansion slurry to one side of the pretreated substrate using a slot coating machine. The wet film thickness is controlled at 0.3-0.8 mm, and the coating speed is 5-15 m / min. Step 3: Preparation of barrier layer impregnation solution. Prepare the impregnation solution by weight as follows: 40-60 parts hydrophobic acrylic resin, 15-25 parts epoxy modified silicone oil, 8-12 parts expansion triggering agent, 5-10 parts nano silica, and 3-5 parts coupling agent. Step 4: Composite treatment, immerse the substrate coated with the expansion layer into the barrier layer impregnation solution, and use roller pressing to assist penetration, with an impregnation time of 10-30 minutes; Step 5: Step curing. First, pre-cur at 80-100℃ for 10-20 minutes, then raise the temperature to 130-150℃ for final curing for 30-60 minutes. After cooling, cut and roll up to obtain composite tape. The swelling trigger is a composite of sodium polyacrylate and acrylamide copolymer, which has a water swelling rate of more than 150%, and the nano silica particles have a particle size of 20-50 nm and are hydrophobically modified.

[0007] Preferably, the plasma cleaning in step one specifically involves: placing the substrate in a plasma reaction chamber, evacuating it to 0.1-1 Pa, introducing argon gas, controlling the gas flow rate to 50-100 sccm, the plasma power to 300-800 W, and the processing time to 2-5 min.

[0008] Preferably, the surface activation treatment in step one includes: immersing the plasma-cleaned substrate in an ethanol solution containing 0.5-1.5 wt% silane coupling agent, ultrasonically treating it at 40-60°C for 10-30 min, and then drying it at 80°C.

[0009] Preferably, the expanded slurry in step two is prepared by the following method: Mix acrylic emulsion, polyethylene glycol and water in a mass ratio of 5:2:3; Add 30-50% of the total weight of the expansion triggering agent and stir and disperse at 50-70℃ for 1-2 hours; Add 0.5-1 part of thickener xanthan gum, homogenize and emulsify at high speed, and let stand to defoam.

[0010] Preferably, the method for preparing the impregnation solution in step three is as follows: Add hydrophobic acrylic resin and epoxy-modified silicone oil to a reaction vessel, heat to 60-80℃ and stir at 200-400 r / min for 20-40 min; Add nano-silica and coupling agent sequentially, and increase the rotation speed to 800-1200 r / min to disperse for 30-50 min; Cool the temperature to below 40°C, add the expansion trigger, and stir at low speed for 10-20 minutes.

[0011] Preferably, the roller-assisted permeation in step four uses a roller extrusion device with an adjustable roller spacing of 0.2-0.6 mm, a linear pressure of 50-150 N / cm, and a roller temperature of 50-70℃.

[0012] Preferably, the expansion trigger is prepared by the following method: Dissolve acrylic acid and acrylamide in deionized water at a molar ratio of 2:1 to 3:1. Add 0.1-0.3 parts of crosslinking agent N,N'-methylenebisacrylamide and 0.5-1 parts of initiator ammonium persulfate; The polymerization reaction was carried out at 70-90℃ for 3-6 hours under nitrogen protection. The product was precipitated with ethanol, dried, and then pulverized through a 200-mesh sieve.

[0013] Preferably, the method for hydrophobic modification of nano-silica is as follows: dispersing silica with a particle size of 20-50 nm in toluene, adding silane coupling agent KH-570, refluxing for 4-8 h, and then centrifuging and drying.

[0014] Preferably, the stepped curing in step five is carried out in a hot air circulating oven, with a wind speed of 0.5-1.5 m / s in the pre-curing stage and 3-5 m / s in the final curing stage.

[0015] Preferably, the composite strip has the following properties: Normal volume resistivity greater than 1×10 15 Ω·cm; The seepage rate is less than 0.1 g / m³ after 72 hours at a water pressure of 1 MPa. 2 ; Its water-induced swelling rate is greater than 200%. The longitudinal tensile strength is greater than 50 MPa.

[0016] (III) Beneficial Effects Compared with the prior art, the present invention provides a process for preparing high water-resistant, expandable composite strips, which has the following advantages: 1. In this invention, during the preparation of high water-resistant expansion composite tape, plasma cleaning and surface activation processes are used to enhance the interfacial bonding between the substrate and the functional layer. At the same time, roller pressing-assisted penetration technology is used to ensure the uniform distribution of the barrier layer impregnation liquid in the expansion layer. This effectively avoids the problems of interlayer peeling and uneven penetration, ensures the integrity of the tape structure and long-term sealing stability, and further improves the mechanical properties and durability of the composite tape.

[0017] 2. In this invention, when preparing a high water-resistant, expandable composite tape, the synthesis process of the expansion trigger and its dispersion method in the slurry are optimized to achieve a highly uniform distribution of the expansion component in the polymer matrix. This allows the tape to produce consistent and controllable expansion behavior after encountering water, reducing the risk of local stress concentration and maintaining a stable physical form during the expansion process, ensuring that the tape can play a reliable sealing role in different application environments.

[0018] 3. In this invention, during the preparation of high water-resistant expansion composite tape, a stepped curing process is designed and temperature and time parameters are precisely controlled to achieve synchronous and synergistic curing of the expansion layer and the barrier layer. This promotes chemical bonding and physical interweaving between functional layers, avoids the generation of internal defect microcracks, and enables the tape to have both excellent mechanical strength and durable water-resistant capability, further improving the applicability and service life of the product under harsh working conditions.

[0019] 4. In this invention, during the preparation of high water-resistant expansion composite tape, by precisely controlling the process parameters of roller-assisted permeation and combining them with the wind speed regulation during the stepped curing stage, the barrier layer impregnation liquid can achieve deep penetration and controllable cross-linking in the expansion layer. This effectively eliminates interlayer micro-gaps and inhibits curing stress concentration, ensuring the compactness of the internal structure of the tape and the interlayer bonding strength. As a result, the final product can maintain a stable water barrier and expansion resilience under long-term water pressure, thus improving the engineering service life of the composite tape.

[0020] 5. In this invention, during the preparation of high water-blocking expansion-type composite tape, a molecular-level hydrophobic barrier is constructed at the substrate interface by using a surface activation treatment with a specific silane coupling agent and the synergistic effect of hydrophobic modified nano-silica. This effectively blocks the penetration path of water molecules along the fiber-resin interface, ensuring that the tape maintains stable electrical insulation performance under long-term humid and hot conditions. This allows the final product to simultaneously meet the requirements for water blocking and insulation reliability in high-voltage cable sealing scenarios. Detailed Implementation

[0021] 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.

[0022] Example 1: Preparation process of high water-resistant expansion composite strip, including the following steps: Step 1: Substrate pretreatment. Polyester braided tape and nylon braided tape are selected as substrates, with a substrate weight of 80g / m². 2 They are subjected to plasma cleaning and surface activation treatment; Step 2: Coating the expansion layer. Apply the expansion slurry to one side of the pretreated substrate using a slot coating machine. Control the wet film thickness to 0.3 mm and the coating speed to 5 m / min. Step 3: Preparation of barrier layer impregnation solution. The impregnation solution is prepared according to the following weight parts: 40 parts hydrophobic acrylic resin, 15 parts epoxy modified silicone oil, 8 parts expansion triggering agent, 5 parts nano silica, and 3 parts coupling agent. Step 4: Composite treatment, immerse the substrate coated with the expansion layer into the barrier layer impregnation solution, and use roller pressing to assist penetration, with an impregnation time of 10 minutes; Step 5: Step curing. First, pre-cur at 80℃ for 10 minutes, then heat to 130℃ for final curing for 30 minutes. After cooling, cut and roll up to obtain composite tape. The swelling trigger is a complex of sodium polyacrylate and acrylamide copolymer, which has a water swelling rate of more than 150%, and the nano silica particles have a diameter of 20 nm and are hydrophobically modified. The plasma cleaning in step one is as follows: the substrate is placed in the plasma reaction chamber, the vacuum is drawn to 0.1 Pa and then argon gas is introduced, the gas flow rate is controlled at 50 sccm, the plasma power is 300W and the processing time is 2 min. The surface activation treatment in step one includes: immersing the plasma-cleaned substrate in an ethanol solution containing 0.5 wt% silane coupling agent, ultrasonically treating it at 40°C for 10 min, and then drying it at 80°C. The expanded slurry in step two is prepared by the following method: Mix acrylic emulsion, polyethylene glycol and water in a mass ratio of 5:2:3; Add 30% of the total weight of the expansion trigger and stir to disperse at 50°C for 1 hour; Add 0.5 parts of thickener xanthan gum, homogenize and emulsify at high speed, and let stand to defoam; The preparation method of the impregnation solution in step three is as follows: Hydrophobic acrylic resin and epoxy-modified silicone oil were added to a reaction vessel, heated to 60°C, and stirred at 200 r / min for 20 min. Nano-silica and coupling agent were added sequentially, and the rotation speed was increased to 800 r / min and dispersed for 30 min. Cool the temperature to below 40°C, add the expansion trigger, and stir at low speed for 10 minutes. In step four, the roller-assisted permeation uses a roller extrusion device with an adjustable roller spacing of 0.2 mm, a linear pressure of 50 N / cm, and a roller temperature of 50 °C. The expansion trigger is prepared by the following method: Dissolve acrylic acid and acrylamide in deionized water at a molar ratio of 2:1; Add 0.1 parts of crosslinking agent N,N'-methylenebisacrylamide and 0.5 parts of initiator ammonium persulfate; The polymerization reaction was carried out at 70°C for 3 hours under nitrogen protection. The product was precipitated with ethanol, dried, and then pulverized through a 200-mesh sieve. The method for hydrophobic modification of nano-silica is as follows: 20 nm silica particles are dispersed in toluene, silane coupling agent KH-570 is added, the mixture is refluxed for 4 h and then centrifuged and dried. Step 5, the stepped curing, is carried out in a hot air circulating oven. The wind speed is 0.5 m / s during the pre-curing stage and 3 m / s during the final curing stage. The composite strip performance meets the following requirements: Normal volume resistivity greater than 1×10 15 Ω·cm; The seepage rate is less than 0.1 g / m³ after 72 hours at a water pressure of 1 MPa. 2 ; Its water-induced swelling rate is greater than 200%. The longitudinal tensile strength is greater than 50 MPa.

[0023] Example 2: Preparation process of high water-resistant expansion composite strip, including the following steps: Step 1: Substrate pretreatment. Polyester braided tape and nylon braided tape are selected as substrates, with a substrate weight of 100g / m². 2 They are subjected to plasma cleaning and surface activation treatment; Step 2: Coating the expansion layer. Apply the expansion slurry to one side of the pretreated substrate using a slot coating machine. The wet film thickness is controlled at 0.6 mm, and the coating speed is 10 m / min. Step 3: Preparation of barrier layer impregnation solution. The impregnation solution is prepared according to the following weight parts: 50 parts hydrophobic acrylic resin, 20 parts epoxy modified silicone oil, 10 parts expansion triggering agent, 7 parts nano silica, and 4 parts coupling agent. Step 4: Composite treatment, immerse the substrate coated with the expansion layer into the barrier layer impregnation solution, and use roller pressing to assist penetration, with an impregnation time of 20 minutes; Step 5: Step curing. First, pre-cur at 90℃ for 15 minutes, then heat to 140℃ for final curing for 50 minutes. After cooling, cut and roll up to obtain composite tape. The swelling trigger is a complex of sodium polyacrylate and acrylamide copolymer, which has a water swelling rate of more than 150%, and the nano silica particles have a diameter of 30 nm and are hydrophobically modified. The plasma cleaning in step one is as follows: the substrate is placed in the plasma reaction chamber, the vacuum is drawn to 0.6 Pa and then argon gas is introduced, the gas flow rate is controlled at 70 sccm, the plasma power is 500W and the processing time is 3 min. The surface activation treatment in step one includes: immersing the plasma-cleaned substrate in an ethanol solution containing 1.0 wt% silane coupling agent, ultrasonically treating it at 50°C for 20 min, and then drying it at 80°C. The expanded slurry in step two is prepared by the following method: Mix acrylic emulsion, polyethylene glycol and water in a mass ratio of 5:2:3; Add 40% of the total weight of the expansion trigger and stir and disperse at 50-70℃ for 1.5 hours; Add 0.7 parts of thickener xanthan gum, homogenize and emulsify at high speed, and let stand to defoam; The preparation method of the impregnation solution in step three is as follows: Hydrophobic acrylic resin and epoxy-modified silicone oil were added to a reaction vessel, heated to 70°C, and stirred at 300 r / min for 30 min. Nano-silica and coupling agent were added sequentially, and the rotation speed was increased to 1000 r / min for 40 min; Cool the temperature to below 40°C, add the expansion trigger, and stir at low speed for 15 minutes. In step four, the roller-assisted permeation uses a roller extrusion device with an adjustable roller spacing of 0.4 mm, a linear pressure of 100 N / cm, and a roller temperature of 60 °C. The expansion trigger is prepared by the following method: Dissolve acrylic acid and acrylamide in deionized water at a molar ratio of 2.5:1; Add 0.2 parts of crosslinking agent N,N'-methylenebisacrylamide and 0.7 parts of initiator ammonium persulfate; The polymerization reaction was carried out at 80℃ for 4 hours under nitrogen protection. The product was precipitated with ethanol, dried, and then pulverized through a 200-mesh sieve. The method for hydrophobic modification of nano-silica is as follows: 40 nm silica particles are dispersed in toluene, silane coupling agent KH-570 is added, the mixture is refluxed for 7 h and then centrifuged and dried. Step 5, the stepped curing, is carried out in a hot air circulating oven. The wind speed is 1.0 m / s during the pre-curing stage and 4 m / s during the final curing stage. The composite strip performance meets the following requirements: Normal volume resistivity greater than 1×10 15 Ω·cm; The seepage rate is less than 0.1 g / m³ after 72 hours at a water pressure of 1 MPa. 2 ; Its water-induced swelling rate is greater than 200%. The longitudinal tensile strength is greater than 50 MPa.

[0024] Example 3: Preparation process of high water-resistant expansion composite strip, including the following steps: Step 1: Substrate pretreatment. Polyester braided tape and nylon braided tape are selected as substrates, with a substrate weight of 120g / m². 2 They are subjected to plasma cleaning and surface activation treatment; Step 2: Coating the expansion layer. Apply the expansion slurry to one side of the pretreated substrate using a slot coating machine. Control the wet film thickness to 0.8 mm and the coating speed to 15 m / min. Step 3: Preparation of barrier layer impregnation solution. The impregnation solution is prepared according to the following weight parts: 60 parts hydrophobic acrylic resin, 25 parts epoxy modified silicone oil, 12 parts expansion triggering agent, 10 parts nano silica, and 5 parts coupling agent. Step 4: Composite treatment, immerse the substrate coated with the expansion layer into the barrier layer impregnation solution, and use roller pressing to assist penetration, with an impregnation time of 30 minutes; Step 5: Step curing. First, pre-cur at 100℃ for 20 minutes, then heat to 150℃ for final curing for 60 minutes. After cooling, cut and roll up to obtain composite tape. The swelling trigger is a complex of sodium polyacrylate and acrylamide copolymer, which has a water swelling rate of more than 150%, and the nano silica particles have a diameter of 50 nm and are hydrophobically modified. The plasma cleaning in step one is as follows: the substrate is placed in the plasma reaction chamber, the vacuum is drawn to 1 Pa and then argon gas is introduced, the gas flow rate is controlled at 100 sccm, the plasma power is 800W, and the processing time is 5 min. The surface activation treatment in step one includes: immersing the plasma-cleaned substrate in an ethanol solution containing 1.5 wt% silane coupling agent, ultrasonically treating it at 60°C for 30 min, and then drying it at 80°C. The expanded slurry in step two is prepared by the following method: Mix acrylic emulsion, polyethylene glycol and water in a mass ratio of 5:2:3; Add 50% of the total weight of the expansion trigger and stir to disperse at 70°C for 2 hours; Add 1 part thickener xanthan gum, homogenize and emulsify at high speed, and let stand to defoam; The preparation method of the impregnation solution in step three is as follows: Hydrophobic acrylic resin and epoxy-modified silicone oil were added to a reaction vessel, heated to 80°C, and stirred at 400 r / min for 40 min. Nano-silica and coupling agent were added sequentially, and the rotation speed was increased to 1200 r / min for 50 min; Cool the temperature to below 40°C, add the expansion trigger, and stir at low speed for 20 minutes. In step four, the roller-assisted permeation uses a roller extrusion device with an adjustable roller spacing of 0.6 mm, a linear pressure of 150 N / cm, and a roller temperature of 70 °C. The expansion trigger is prepared by the following method: Dissolve acrylic acid and acrylamide in deionized water at a molar ratio of 3:1. Add 0.3 parts of crosslinking agent N,N'-methylenebisacrylamide and 1 part of initiator ammonium persulfate; The polymerization reaction was carried out at 90℃ for 6 hours under nitrogen protection. The product was precipitated with ethanol, dried, and then pulverized through a 200-mesh sieve. The method for hydrophobic modification of nano-silica is as follows: 50 nm silica particles are dispersed in toluene, silane coupling agent KH-570 is added, the mixture is refluxed for 8 h and then centrifuged and dried. Step 5, the stepped curing, is carried out in a hot air circulating oven. The wind speed is 1.5 m / s during the pre-curing stage and 5 m / s during the final curing stage. The composite strip performance meets the following requirements: Normal volume resistivity greater than 1×10 15 Ω·cm; The seepage rate is less than 0.1 g / m³ after 72 hours at a water pressure of 1 MPa. 2 ; Its water-induced swelling rate is greater than 200%. The longitudinal tensile strength is greater than 50 MPa.

[0025] Comparative Example 1: The difference between this comparative example and Example 1 is that no expansion triggering agent was added when preparing the expansion slurry in this comparative example.

[0026] Comparative Example 2 differs from Example 2 in that nano-silica was not added when preparing the barrier layer impregnation solution in this comparative example.

[0027] Comparative Example 3 differs from Example 3 in that the substrate in this comparative example was not subjected to plasma cleaning and surface activation treatment.

[0028] Comparative Example 4 differs from Example 3 in that the pre-curing stage is eliminated in the stepped curing process, and the final curing is carried out directly at high temperature.

[0029] The high water-resistant, swelling composite tapes prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests. The test items and methods are as follows: Water resistance test: The water pressure was maintained at 1.0 MPa for 72 hours, and the water seepage per unit area was measured. Expansion characteristics test: Immerse the sample in distilled water at 25°C and measure the volume expansion rate after 24 hours; Interfacial bonding strength: The bonding strength between the barrier layer and the expansion layer was determined by a 90° peel test; Durability test: After aging in an environment of 85℃ / 85%RH for 500 hours, repeat the above three tests and calculate the performance retention rate.

[0030] The test data of the composite strips prepared in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below:

[0031] By comparing and analyzing the data in the table, it can be seen that the high water-resistant expandable composite tape prepared using the processes of Examples 1-3 shows improved performance compared to the tape prepared using the processes of Comparative Examples 1-4. This indicates that in the preparation of the high water-resistant expandable composite tape, the use of plasma cleaning and surface activation processes enhances the interfacial bonding between the substrate and the functional layer. Simultaneously, the use of roller-assisted permeation technology ensures the uniform distribution of the barrier layer impregnation liquid in the expandable layer, effectively avoiding interlayer delamination and uneven permeation. This guarantees the integrity of the tape structure and long-term sealing stability, further improving the mechanical properties and durability of the composite tape. By optimizing the synthesis process of the expansion trigger and its dispersion method in the slurry, a highly uniform distribution of the expansion component in the polymer matrix is ​​achieved, enabling the tape to exhibit consistent and controllable expansion behavior upon contact with water, reducing the risk of local stress concentration, and maintaining a stable physical morphology during expansion. This ensures the tape can perform reliably in various application environments. By designing a stepped curing process and precisely controlling temperature and time parameters, the expansion layer and barrier layer are effectively integrated. Synchronous and synergistic curing promotes chemical bonding and physical interweaving between functional layers, avoiding the generation of internal defects and microcracks. This gives the tape both excellent mechanical strength and durable water-blocking ability, further improving the product's applicability and service life under harsh working conditions. By precisely controlling the process parameters of roller-assisted penetration and combining wind speed regulation in the stepped curing stage, deep penetration and controllable cross-linking of the barrier layer impregnation liquid in the expansion layer are achieved. This effectively eliminates interlayer micro-gap and inhibits curing stress concentration, ensuring the compactness of the tape's internal structure and the strength of interlayer bonding. This allows the final product to maintain a stable water-blocking barrier and expansion resilience under long-term water pressure, improving the engineering service life of the composite tape. Through the synergistic effect of surface activation treatment with specific silane coupling agents and hydrophobic modified nano-silica, a molecular-level hydrophobic barrier is constructed at the substrate interface. This effectively blocks the penetration path of water molecules along the fiber-resin interface, ensuring that the tape maintains stable electrical insulation performance under long-term humid and hot conditions. This allows the final product to simultaneously meet water-blocking requirements and insulation reliability requirements in high-voltage cable sealing scenarios.

[0032] By comparing and analyzing the data in the table, it can be seen that the composite strip prepared by the process of the present invention has the integrity of the strip structure, long-term sealing stability and durability. This shows that the high water resistance expansion type composite strip preparation process provided by the present invention has a broader market prospect and is more suitable for promotion.

[0033] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for preparing high water-resistant, expandable composite strip, characterized in that, Includes the following steps: Step 1: Substrate pretreatment. Polyester braided tape and nylon braided tape are selected as substrates, with a substrate weight of 80-120 g / m². 2 They are subjected to plasma cleaning and surface activation treatment. Step 2: Coating the expansion layer. Apply the expansion slurry to one side of the pretreated substrate using a slot coating machine. The wet film thickness is controlled at 0.3-0.8 mm, and the coating speed is 5-15 m / min. Step 3: Preparation of barrier layer impregnation solution. Prepare the impregnation solution by weight as follows: 40-60 parts hydrophobic acrylic resin, 15-25 parts epoxy modified silicone oil, 8-12 parts expansion triggering agent, 5-10 parts nano silica, and 3-5 parts coupling agent. Step 4: Composite treatment, immerse the substrate coated with the expansion layer into the barrier layer impregnation solution, and use roller pressing to assist penetration, with an impregnation time of 10-30 minutes; Step 5: Step curing. First, pre-cur at 80-100℃ for 10-20 minutes, then raise the temperature to 130-150℃ for final curing for 30-60 minutes. After cooling, cut and roll up to obtain composite tape. The swelling trigger is a composite of sodium polyacrylate and acrylamide copolymer, which has a water swelling rate of more than 150%, and the nano silica particles have a particle size of 20-50 nm and are hydrophobically modified.

2. The manufacturing process of the high water-resistant, expandable composite strip according to claim 1, characterized in that, The plasma cleaning in step one specifically involves placing the substrate in a plasma reaction chamber, evacuating it to 0.1-1 Pa, introducing argon gas, controlling the gas flow rate at 50-100 sccm, the plasma power at 300-800 W, and the processing time at 2-5 min.

3. The manufacturing process of the high water-resistant, expandable composite strip according to claim 1, characterized in that, The surface activation treatment in step one includes: immersing the plasma-cleaned substrate in an ethanol solution containing 0.5-1.5 wt% silane coupling agent, ultrasonically treating it at 40-60℃ for 10-30 min, and then drying it at 80℃.

4. The manufacturing process of the high water-resistant, expandable composite strip according to claim 1, characterized in that, The expanded slurry in step two is prepared by the following method: Mix acrylic emulsion, polyethylene glycol and water in a mass ratio of 5:2:3; Add 30-50% of the total weight of the swelling trigger and stir and disperse at 50-70℃ for 1-2 hours; Add 0.5-1 part of thickener xanthan gum, homogenize and emulsify at high speed, and let stand to defoam.

5. The preparation process of the high water-resistant, expandable composite strip according to claim 1, characterized in that, The method for preparing the impregnation solution in step three is as follows: Add hydrophobic acrylic resin and epoxy-modified silicone oil to a reaction vessel, heat to 60-80℃ and stir at 200-400 r / min for 20-40 min; Add nano-silica and coupling agent sequentially, and increase the rotation speed to 800-1200 r / min to disperse for 30-50 min; Cool the temperature to below 40°C, add the expansion trigger, and stir at low speed for 10-20 minutes.

6. The manufacturing process of the high water-resistant, expandable composite strip according to claim 1, characterized in that: In step four, the roller-assisted permeation uses a roller extrusion device with an adjustable roller spacing of 0.2-0.6 mm, a linear pressure of 50-150 N / cm, and a roller temperature of 50-70℃.

7. The process for preparing high water-resistant, expandable composite strip according to claim 1, characterized in that, The expansion trigger agent is prepared by the following method: Dissolve acrylic acid and acrylamide in deionized water at a molar ratio of 2:1 to 3:

1. Add 0.1-0.3 parts of crosslinking agent N,N'-methylenebisacrylamide and 0.5-1 parts of initiator ammonium persulfate; The polymerization reaction was carried out at 70-90℃ for 3-6 hours under nitrogen protection. The product was precipitated with ethanol, dried, and then pulverized through a 200-mesh sieve.

8. The preparation process of the high water-resistant, expandable composite strip according to claim 1, characterized in that, The method for hydrophobic modification of nano-silica is as follows: silica with a particle size of 20-50 nm is dispersed in toluene, silane coupling agent KH-570 is added, the mixture is refluxed for 4-8 hours and then centrifuged and dried.

9. The manufacturing process of the high water-resistant, expandable composite strip according to claim 1, characterized in that: The step-by-step curing in step five is carried out in a hot air circulating oven, with a wind speed of 0.5-1.5 m / s during the pre-curing stage and 3-5 m / s during the final curing stage.

10. The process for preparing high water-resistant, expandable composite strip according to claim 1, characterized in that, The composite strip material meets the following performance requirements: Normal volume resistivity greater than 1×10 15 Ω·cm; The seepage rate is less than 0.1 g / m³ after 72 hours at a water pressure of 1 MPa. 2 ; Its water-induced swelling rate is greater than 200%. The longitudinal tensile strength is greater than 50 MPa.

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