A high-pressure-resistant and wear-resistant composite structure sealing tape and its preparation method

Abstract

The present invention relates to a high-pressure-resistant and wear-resistant composite structure sealing tape and a preparation method thereof, and belongs to the field of sealing tapes. The sealing tape of the present invention is composited by a polytetrafluoroethylene layer, a polyurethane layer and a pressure-sensitive adhesive layer. The polytetrafluoroethylene layer has good wear resistance, creep resistance and resilience; the polyurethane layer has the characteristics of high elasticity, high weather resistance and the like, giving it excellent conformability and low contact pressure sealing effect; the pressure-sensitive adhesive layer gives the product excellent construction technology, can provide moderate adhesion, and meet the requirements of repeated installation and maintenance guarantee during the application process. Therefore, the three-layer composite structure brings into play the respective advantages of the three layers of materials, giving the sealing tape the characteristics of high pressure resistance, wear resistance, fatigue resistance and long life. The composite structure sealing tape of the present invention can be used for sealing in the fields of aerospace, rail transportation, electronic components, etc., and is particularly suitable for structural sealing of various types of helicopters.

Description

Technical Field

[0001] The present invention relates to the field of sealing tapes, and in particular to a sealing tape with a high pressure resistance and wear resistance composite structure and a preparation method thereof. Background Art

[0002] Sealing components is essential in a wide range of fields, including aerospace, rail transportation, and electronics. Sealing materials must be easy to install, have a long lifespan, and offer reliable sealing performance. Improper sealing can lead to corrosion of structures and systems, significantly reducing service life and increasing costs.

[0003] In the aviation field, helicopter airframe structural sealing involves installing sealing materials at the joints between frames and beams, as well as other sealing covers, to prevent internal corrosion of the frames, beams, and airframe structure caused by the infiltration of moisture, salt spray, and dirt. Structural and systemic corrosion can reduce the lifespan of some helicopter systems. Furthermore, the maintenance and repairs caused by corrosion significantly increase the lifecycle cost of a helicopter, significantly impacting its operational availability and reliability. Therefore, the selection of sealing materials is crucial; they must not only provide excellent sealing performance but also possess good processability and durability.

[0004] Traditional sealing materials including sealing rubber, sealant, expanded tetrafluoroethylene, etc. can only solve part of the sealing problem and cannot provide a one-stop comprehensive solution. Therefore, there is an urgent need to provide a sealing material that can solve the strong vibration and large displacement environment of helicopters and has the characteristics of high pressure resistance, wear resistance, fatigue resistance and long life. Summary of the Invention

[0005] In order to solve the problems existing in existing sealing materials, the purpose of the present invention is to provide a high-pressure-resistant and wear-resistant composite structure sealing tape and its preparation method. The sealing tape of the present invention is composed of a polytetrafluoroethylene layer, a polyurethane layer and a pressure-sensitive adhesive layer. The polytetrafluoroethylene layer has good wear resistance, creep resistance and resilience. The polyurethane layer has the characteristics of high elasticity and high weather resistance, which gives it excellent conformability and low contact pressure sealing effect. The pressure-sensitive adhesive layer gives the product excellent construction technology and can provide moderate adhesion to meet the requirements of repeated installation and maintenance during application. In addition, since the polyurethane resin used in the present invention is a polyurethane resin synergistically modified by polysulfide and polyacrylic acid, on the one hand, the introduction of polysulfide improves the solvent resistance of the polyurethane resin, and on the other hand, the introduction of polyacrylic acid makes the polyurethane layer and the acrylate pressure-sensitive adhesive layer have good structural similarity and compatibility, making the interface bonding performance of the two layers more excellent, thereby improving the overall performance of the sealing tape.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] Provided is a high-pressure-resistant and wear-resistant composite structural sealing tape, which is composed of a polytetrafluoroethylene layer, a polyurethane layer and a pressure-sensitive adhesive layer. The polyurethane layer is composed of a polyurethane resin synergistically modified by polysulfide and polyacrylic acid and a glass fiber mesh, and the pressure-sensitive adhesive layer is an acrylic ester pressure-sensitive adhesive layer. Wherein, the modified polyurethane resin is composed of two components A and B, component A is a polyacrylic acid modified active hydrogen component, and component B is a polysulfide modified isocyanate prepolymer component. After component A and component B are mixed in a weight ratio of 1:1, they are cured at room temperature to obtain the polysulfide and polyacrylic acid synergistically modified polyurethane resin. Wherein,

[0008] The raw material composition and weight ratio of the A component are as follows:

[0009]

[0010] The raw material composition and weight ratio of the B component are as follows:

[0011]

[0012] In the polyurethane resin component A, the trifunctional polyether polyol is polyoxypropylene triol with a molecular weight of 3000-7000; the difunctional liquid polysulfide has a molecular weight of 1000-2500; the polyacrylic acid has a molecular weight of 2000-5000; and the catalyst A is at least one of an organic bismuth catalyst and an organic zinc catalyst.

[0013] In the polyurethane resin component B, the difunctional liquid polysulfide has a molecular weight of 1000-2500; the polyether diol is polyoxypropylene diol with a molecular weight of 500-2000; the polyether triol is polyoxypropylene triol with a molecular weight of 3000-7000; the diisocyanate is at least one of toluene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and hexamethylene dicyanate; the antioxidant is antioxidant 1010; and the catalyst B is at least one of dibutyltin dilaurate, stannous octoate, and triethylamine.

[0014] The thickness of the polytetrafluoroethylene layer is 0.1-0.2 mm; the thickness of the glass fiber mesh is 0.3-0.4 mm, and the pore size is 1.5-1.6 mm; the thickness of the acrylic pressure-sensitive adhesive layer is 0.1-0.2 mm.

[0015] Furthermore, the present invention also provides a method for preparing a high-pressure-resistant and wear-resistant composite structure sealing tape, comprising the following steps:

[0016] (1) Preparation of component A

[0017] According to parts by weight, trifunctional polyether polyol and difunctional liquid polysulfide were added to a reactor and mixed. The mixture was heated to 100-120°C and vacuum-dried for 2 hours. The mixture was then cooled to room temperature. Polyacrylic acid and catalyst A were added. Bubbles were removed under a vacuum pressure of -0.095 to 0.1 MPa. After stirring evenly, the vacuum was released with dry argon to obtain the modified active hydrogen component of component A. The resulting mixture was placed in a sealed container.

[0018] (2) Preparation of component B

[0019] Mix polyether diol, polyether triol, difunctional liquid polysulfide, and antioxidant according to parts by weight, raise the temperature to 100-120°C, remove water under vacuum for 2 hours, then cool to 60-80°C, add diisocyanate and catalyst B, react at 70-80°C under argon protection for 3 hours to obtain component B, a polysulfide-modified isocyanate prepolymer component, and transfer the mixture to a sealed container to isolate it from air and moisture for storage;

[0020] (3) Preparation of composite structural sealing tape

[0021] After degassing, component A and component B are mixed evenly at room temperature in a weight ratio of 1:1, and then coated on the surface of the polytetrafluoroethylene layer. A glass fiber mesh is placed on the coated adhesive surface, and the mixed components A and B are again coated on the surface of the glass fiber mesh, and the coating is evenly applied by scraping. The mixture is allowed to stand at room temperature for 48 hours until it is completely cured. Finally, acrylic pressure-sensitive adhesive is sprayed on the surface and the size is cut according to the needs of use to obtain a composite structural sealing tape.

[0022] The composite structure sealing tape has a total thickness of 1.0-1.8 mm and a density of 0.11-0.15 g / cm 3 .

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The sealing tape of this invention is composed of a composite of a polytetrafluoroethylene layer, a polyurethane layer, and a pressure-sensitive adhesive layer. The polytetrafluoroethylene layer exhibits excellent wear resistance, creep resistance, and resilience; the polyurethane layer exhibits high elasticity and weather resistance, giving it excellent conformability and a low-contact-pressure sealing effect; the pressure-sensitive adhesive layer provides excellent construction process, providing moderate adhesion and meeting the requirements for repeated installation and maintenance during use. Thus, the three-layer composite structure leverages the advantages of each material, endowing the sealing tape with high pressure resistance, wear resistance, fatigue resistance, and a long life.

[0025] 2. The polyurethane resin used in the sealing tape of the present invention is a polyurethane resin synergistically modified with polysulfide and polyacrylic acid. On the one hand, the introduction of polysulfide improves the solvent resistance of the polyurethane resin. On the other hand, the introduction of polyacrylic acid enables the polyurethane layer and the acrylic ester pressure-sensitive adhesive layer to have good structural similarity and compatibility, making the interface bonding performance of the two layers more excellent, thereby improving the overall performance of the sealing tape.

[0026] 3. The modified polyurethane resin used in the sealing tape of the present invention has low hardness, high elasticity and self-adhesive effect. When compounded with the glass fiber mesh, it gives the sealing tape higher mechanical strength, can withstand higher installation pressure and vibration fatigue load, has good sealing effect and long service life.

[0027] 4. Since the composite structure sealing tape of the present invention avoids the use of organic silicon materials, no silicone oil residue will be left during the use or removal of the tape.

[0028] 5. The composite structural sealing tape of the present invention has a wide range of applications and can be used in aerospace, rail transportation, electronic components and other fields, and is particularly suitable for structural sealing of various types of helicopters. DETAILED DESCRIPTION

[0029] To make the objects, technical solutions, and advantages of the present invention more apparent, the present invention is further described with reference to the following examples, which are provided by way of illustration rather than limitation. The experimental methods in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are all commercially available unless otherwise specified.

[0030] Example 1

[0031] (1) Preparation of component A

[0032] 30 parts of polyoxypropylene triol (molecular weight 5000) and 25 parts of difunctional liquid polysulfide (molecular weight 2500) were added to a reactor and mixed thoroughly. The temperature was raised to 110° C. and vacuum-dried for 2 hours. The temperature was then lowered to room temperature. After the moisture content of the liquid was detected to be less than 100 ppm, 10 parts of polyacrylic acid (molecular weight 3000) and 0.016 parts of an organic bismuth catalyst were added. The mixture was deaerated under a vacuum state of 0.1 MPa and vigorously stirred until the system was uniform. The vacuum was then released with dry argon to obtain component A. The obtained mixture was placed in a sealed container.

[0033] (2) Preparation of component B

[0034] 10 parts of difunctional liquid polysulfide (molecular weight 2500), 20 parts of polyoxypropylene diol (molecular weight 2000) and 12 parts of polyoxypropylene triol (molecular weight 5000) were added to a dry 500mL four-necked bottle, and then 0.15 parts of antioxidant 1010 were added. The temperature was raised to 110°C, and the water was removed by vacuum for 2 hours. After the water content of the liquid was detected to be less than 100ppm, the temperature was lowered to 70°C, 23.5 parts of dicyclohexylmethane diisocyanate and 0.034 parts of dibutyltin dilaurate were added as a catalyst, and the mixture was reacted at 80°C for 3 hours under argon protection to obtain the polysulfide-modified isocyanate prepolymer component B. The prepolymer was then transferred to a sealed container to isolate it from air and moisture and stored in a sealed container. (3) Preparation of composite structural sealing tape

[0035] After degassing, components A and B were mixed evenly at room temperature in a weight ratio of 1:1, and then coated on the surface of the polytetrafluoroethylene layer. A glass fiber mesh was placed on the coated adhesive surface, and the mixed components A and B were again coated on the surface of the glass fiber mesh, evenly scraped, and allowed to stand at room temperature for 48 hours to completely cure. Finally, acrylic pressure-sensitive adhesive was sprayed on the surface and cut to an appropriate size as needed to prepare a composite structural sealing tape 1 with a thickness of 1.2 mm.

[0036] Example 2

[0037] (1) Preparation of component A

[0038] 35 parts of polyoxypropylene triol (molecular weight 5000) and 20 parts of difunctional liquid polysulfide (molecular weight 2500) were added to a reactor and mixed thoroughly. The mixture was heated to 110° C. and vacuum-dried for 2 hours. The mixture was then cooled to room temperature. After the moisture content of the liquid was detected to be less than 100 ppm, 20 parts of polyacrylic acid (molecular weight 3000) and 0.016 parts of an organic bismuth catalyst were added. The mixture was deaerated under a vacuum state of 0.1 MPa and vigorously stirred until the system was uniform. The vacuum was then released with dry argon to obtain component A. The obtained mixture was placed in a sealed container.

[0039] (2) Preparation of component B

[0040] 15 parts of difunctional liquid polysulfide (molecular weight 2500), 15 parts of polyoxypropylene diol (molecular weight 2000) and 20 parts of polyoxypropylene triol (molecular weight 5000) were added to a dry 500mL four-necked flask, and 0.18 parts of antioxidant 1010 were added. The temperature was raised to 110°C, and vacuum-dried for 2 hours. After the liquid moisture content was detected to be less than 100ppm, the temperature was lowered to 70°C, 26.5 parts of composite dicyclohexylmethane diisocyanate and diphenylmethane diisocyanate were added, and 0.5 parts of stannous octoate was added as a catalyst. The mixture was reacted at 80°C under argon protection for 3 hours to obtain a polysulfide-modified isocyanate prepolymer component B, which was then transferred to a sealed container to isolate it from air and moisture and sealed for storage;

[0041] (3) Preparation of composite structural sealing tape

[0042] After degassing, components A and B were mixed evenly at room temperature in a weight ratio of 1:1, and then coated on the surface of the polytetrafluoroethylene layer. A glass fiber mesh was placed on the coated adhesive surface, and the mixed components A and B were again coated on the surface of the glass fiber mesh, evenly spread by scraping, and allowed to stand at room temperature for 48 hours to completely cure. Finally, acrylic pressure-sensitive adhesive was sprayed on the surface and cut to appropriate size as needed to produce a composite structural sealing tape 2 with a thickness of 1.4 mm.

[0043] Example 3

[0044] (1) Preparation of component A

[0045] 40 parts of polyoxypropylene triol (molecular weight 5000) and 15 parts of difunctional liquid polysulfide (molecular weight 2500) were added to a reactor and mixed thoroughly. The temperature was raised to 110° C. and vacuum-dried for 2 hours. The temperature was then lowered to room temperature. After the moisture content of the liquid was detected to be less than 100 ppm, 30 parts of polyacrylic acid (molecular weight 3000) and 0.018 parts of an organic bismuth catalyst were added. The mixture was deaerated under a vacuum pressure of 0.1 MPa. After vigorously stirring until the system was uniform, the vacuum was released with dry argon to obtain component A. The obtained mixture was placed in a sealed container.

[0046] (2) Preparation of component B

[0047] 20 parts of difunctional liquid polysulfide (molecular weight 2500), 30 parts of polyoxypropylene diol (molecular weight 2000) and 10 parts of polyoxypropylene triol (molecular weight 5000) were added to a dry 500mL four-necked flask, and 0.2 parts of antioxidant 1010 were added. The temperature was raised to 110°C, and vacuum-dried for 2 hours. After the moisture content of the liquid was detected to be less than 100ppm, the temperature was lowered to 70°C, 35 parts of diphenylmethane diisocyanate and 0.045 parts of dibutyltin dilaurate were added as catalysts, and the mixture was reacted at 80°C for 3 hours under argon protection to obtain a polysulfide-modified isocyanate prepolymer component (component B). The prepolymer was then transferred to a sealed container to isolate it from air and moisture and sealed for storage;

[0048] (3) Preparation of composite structural sealing tape

[0049] After degassing, components A and B were mixed evenly at room temperature in a weight ratio of 1:1, and then coated on the surface of the polytetrafluoroethylene layer. A glass fiber mesh was placed on the coated adhesive surface, and the mixed components A and B were again coated on the surface of the glass fiber mesh, evenly spread by scraping, and allowed to stand at room temperature for 48 hours to completely cure. Finally, acrylic pressure-sensitive adhesive was sprayed on the surface and cut to appropriate size as needed to produce a composite structural sealing tape 3 with a thickness of 1.3 mm.

[0050] Comparative Example 1

[0051] (1) Preparation of component A:

[0052] 45 parts of polyoxypropylene triol (molecular weight 5000) were added to a reactor, heated to 110°C, vacuum-dried for 2 hours, and then cooled to room temperature. After the moisture content of the liquid was detected to be less than 100 ppm, 20 parts of fumed silica and 0.016 parts of an organic bismuth catalyst were added. Bubbles were removed under a vacuum state of 0.1 MPa. After vigorous stirring until the system was uniform, the vacuum was released with dry argon to obtain component A. The obtained mixture was placed in a sealed container;

[0053] (2) Preparation of component B:

[0054] 20 parts of polyoxypropylene diol (molecular weight 2000) and 22 parts of polyoxypropylene triol (molecular weight 5000) were added to a dry 500 mL four-necked flask, and 0.15 parts of antioxidant 1010 were added. The temperature was raised to 110° C. and vacuum-dried for 2 hours. After the moisture content of the liquid was detected to be less than 100 ppm, the temperature was lowered to 70° C., 23.5 parts of dicyclohexylmethane diisocyanate and 0.034 parts of dibutyltin dilaurate were added as a catalyst, and the mixture was reacted at 80° C. for 3 hours under argon protection to obtain component B. The component was then transferred to a sealed container to isolate it from air and moisture and sealed for storage;

[0055] (3) Preparation of composite structural sealing tape

[0056] After degassing, components A and B were mixed evenly at room temperature in a weight ratio of 1:1, and then coated on the surface of the polytetrafluoroethylene layer. A glass fiber mesh was placed on the coated adhesive surface, and the mixed components A and B were again coated on the surface of the glass fiber mesh, evenly scraped, and allowed to stand at room temperature for 48 hours to completely cure. Finally, acrylic pressure-sensitive adhesive was sprayed on the surface and cut to appropriate size as needed to produce a composite structural sealing tape 4 with a thickness of 1.2 mm.

[0057] Performance Testing

[0058] 1. Peel strength: Peeled off aluminum alloy plate at 180 degrees, measured in accordance with GB / T 2792.

[0059] 2.Tensile strength: tested in accordance with GB / T 528-2009 standard using Sansi UTM5105 universal tensile testing machine.

[0060] 3. Water vapor transmission rate: measured in accordance with GB / T 30412-2013 using the appropriate sensor method.

[0061] 4.Solvent resistance: The solvent resistance of composite structural sealing tape is tested by placing the tape in water and No. 15 aviation hydraulic oil, respectively, and keeping it at 30°C for 30 days. The weight change of the tape before and after immersion is measured, and the oil absorption rate and water absorption rate are calculated.

[0062] The absorption rate is calculated as:

[0063]

[0064] In the formula: m1——represents the mass after immersion;

[0065] m0——represents the mass before immersion.

[0066] The performance tests of the embodiments and comparative examples are shown in Table 1.

[0067] Table 1 Performance comparison between examples and comparative examples

[0068]

[0069]

[0070] The test data in Table 1 shows that the peel strength and tensile strength of the Example and Comparative Example tapes differ little, demonstrating comparable performance. However, the water vapor transmission rate, oil absorption rate, and water absorption rate of the Example tapes are all lower than those of the Comparative Example tapes, indicating that the solvent resistance of the Example tapes is significantly improved. This is because the polyurethane resin used in the sealing tape material of the present invention incorporates solvent-resistant polysulfide, significantly enhancing the tape's solvent resistance. The comparative example tapes, however, use unmodified polyurethane resin, resulting in poor solvent resistance.

[0071] The above embodiments are implementation schemes with significant features of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the scope of protection of the present invention.

Claims

1. A high pressure-resistant and wear-resistant composite structure sealing tape, which is composed of a polytetrafluoroethylene layer, a polyurethane layer and a pressure-sensitive adhesive layer, characterized in that: The polyurethane layer is composed of a polyurethane resin modified by polysulfide and polyacrylic acid and a glass fiber mesh. The pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer. The modified polyurethane resin is composed of two components, A and B. Component A is a polyacrylic acid modified active hydrogen component, and component B is a polysulfide modified isocyanate prepolymer component. Components A and B are mixed in a weight ratio of 1:1 and cured at room temperature to obtain the polysulfide and polyacrylic acid modified polyurethane resin. The raw material composition and weight ratio of the A component are as follows: The raw material composition and weight ratio of the B component are as follows:

2. The high pressure-resistant and wear-resistant composite structure sealing tape according to claim 1, characterized in that: In the polyurethane resin component A, the trifunctional polyether polyol is polyoxypropylene triol with a molecular weight of 3000-7000; the difunctional liquid polysulfide has a molecular weight of 1000-2500; the polyacrylic acid has a molecular weight of 2000-5000; and the catalyst A is at least one of an organic bismuth catalyst and an organic zinc catalyst.

3. The high pressure-resistant and wear-resistant composite structure sealing tape according to claim 1, characterized in that: In the polyurethane resin component B, the difunctional liquid polysulfide has a molecular weight of 1000-2500; the polyether diol is polyoxypropylene diol with a molecular weight of 500-2000; the polyether triol is polyoxypropylene triol with a molecular weight of 3000-7000; the diisocyanate is at least one of toluene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and hexamethylene dicyanate; the antioxidant is antioxidant 1010; and the catalyst B is at least one of dibutyltin dilaurate, stannous octoate, and triethylamine.

4. The high pressure-resistant and wear-resistant composite structure sealing tape according to claim 1, characterized in that: The thickness of the polytetrafluoroethylene layer is 0.1-0.2 mm; the thickness of the glass fiber mesh is 0.3-0.4 mm, and the pore size is 1.5-1.6 mm; the thickness of the acrylic ester pressure-sensitive adhesive layer is 0.1-0.2 mm.

5. The high pressure-resistant and wear-resistant composite structure sealing tape according to claim 1, characterized in that: The following steps are involved: (1) Preparation of component A According to parts by weight, trifunctional polyether polyol and difunctional liquid polysulfide were added to a reactor and mixed. The mixture was heated to 100-120°C and vacuum-dried for 2 hours. The mixture was then cooled to room temperature. Polyacrylic acid and catalyst A were added. Bubbles were removed under a vacuum pressure of -0.095 to 0.1 MPa. After stirring evenly, the vacuum was released with dry argon to obtain the modified active hydrogen component of component A. The resulting mixture was placed in a sealed container. (2) Preparation of component B Mix polyether diol, polyether triol, difunctional liquid polysulfide, and antioxidant according to parts by weight, raise the temperature to 100-120°C, remove water under vacuum for 2 hours, then cool to 60-80°C, add diisocyanate and catalyst B, react at 70-80°C under argon protection for 3 hours to obtain component B, a polysulfide-modified isocyanate prepolymer component, and transfer the mixture to a sealed container to isolate it from air and moisture for storage; (3) Preparation of composite structural sealing tape After degassing, component A and component B are mixed evenly at room temperature in a weight ratio of 1:1, and then coated on the surface of the polytetrafluoroethylene layer. A glass fiber mesh is placed on the coated adhesive surface, and the mixed components A and B are again coated on the surface of the glass fiber mesh, and the coating is evenly applied by scraping. The mixture is allowed to stand at room temperature for 48 hours until it is completely cured. Finally, acrylic pressure-sensitive adhesive is sprayed on the surface and the size is cut according to the needs of use to obtain a composite structural sealing tape.

6. The high pressure-resistant and wear-resistant composite structure sealing tape according to claim 1, characterized in that: The composite structure sealing tape has a total thickness of 1.0-1.8 mm and a density of 0.11-0.15 g / cm 3 .

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