A method for preparing a flap seal, and the flap seal itself.

Abstract

This invention provides a method for preparing a flap seal and the flap seal itself. The method includes: S1, applying a 0.005-0.015mm thick layer of liquid silicone to the surface of the coating layer and then vulcanizing it; then calendering a 0.05-0.15mm thick layer of solid modified silicone on a three-roll calender to obtain a modified coating layer after vulcanization; S2, calendering a 0.5-1.0mm thick filler layer on the modified coating layer using a three-roll calender, wherein the filler layer is made of solid modified silicone; S3, covering the upper and lower sides of the core layer with the filler layer and placing it in a mold for compression molding. This invention solves the problem of excess adhesive on the product surface during compression molding after rubber fabric lamination, leading to large precision errors and low pass rates in large-size aerospace materials; the surface coating layer has high bonding strength with silicone, does not delaminate, and extends product life; the silicone has excellent low-temperature performance, with TR10 below -70℃, improving low-temperature sealing performance.

Description

Technical Field

[0001] This invention relates to the field of aviation technology, and more specifically, to a method for preparing a flap seal and a flap seal. Background Technology

[0002] Aircraft flaps are connected to the main wing surface via rotary actuators or hinge mechanisms to deflect and change the wing camber, which is crucial for improving the aircraft's lift and maneuverability. Due to the inherent kinematic relationship between the flaps and the main wing surface, a dynamically changing gap inevitably occurs between them during flap deflection, necessitating flap sealing at this gap.

[0003] Flap seals typically use fiberglass board and a covering layer as the skeleton and covering layer, respectively, and fill the space between them with silicone through vulcanization molding. However, because the silicone is in a viscous state under the high temperature and high pressure vulcanization conditions of the vulcanizing press, it is easy to overflow from the mesh of the covering layer, which leads to the following adverse effects: (1) The product surface is difficult to clean, affecting the pass rate; (2) The overflowing silicone affects the sealing effect; (3) It occupies the top position, resulting in uneven product size and poor precision; (4) It increases the friction with the wing surface and shortens the product life. Summary of the Invention

[0004] The problem solved by this invention is that the current flap sealing process is unreasonable, resulting in low product qualification rate, poor large-size precision, and short lifespan.

[0005] To solve the above problems, the present invention provides a method for preparing a flap seal, comprising: S1, coating the surface of the coating layer with a liquid silicone with a thickness of 0.005-0.015 mm and then vulcanizing it, and then calendering a solid modified silicone with a thickness of 0.05-0.15 mm on a three-roll calender to obtain a modified coating layer after vulcanization; S2, calendering a filler layer with a thickness of 0.5-1.0 mm on the modified coating layer using a three-roll calender, wherein the filler layer is made of solid modified silicone; S3, coating the upper and lower sides of the core layer with the filler layer and placing it in a mold for molding and vulcanization.

[0006] Preferably, the coating layer in step S1 is pretreated as follows: the coating layer is dried at 95℃-100℃ for 2-4 hours, then placed in a vacuum plasma device and evacuated to 0.1-100 Pa for 3-6 minutes, and then subjected to a plasma exchange at 600-1000 cm⁻¹. 3 Oxygen is introduced at a rate of / min for 120 seconds.

[0007] Preferably, the solid modified silica gel comprises: 100 parts of ordinary silica gel, 10-20 parts of phenyl vinyl silicone oil, 2-5 parts of phenyl silicone resin, 0.2-0.5 parts of HMDS inhibitor, 4-10 parts of fumed silica, and 1-3 parts of KH550 coupling agent. It is prepared by the following method: ordinary silica gel is subjected to open-milling, passing through a thin stream 4-6 times. Phenyl vinyl silicone oil and inhibitor are added sequentially in appropriate amounts, and the mixture is kneaded for 3-5 minutes. Then, phenyl silicone resin is added in appropriate amounts and kneaded for 5-8 minutes. Finally, KH550 coupling agent and fumed silica are added in appropriate amounts, and the mixture is kneaded for 3-5 minutes. The mixture is then passed through a thin stream 4-6 times, sheeted, cooled, and allowed to stand to obtain the final product.

[0008] Preferably, the liquid silicone in step S1 is a vinyl silane type, and the coating parameters are: a cloth speed of 8-12 m / min.

[0009] Preferably, the process parameters for the calendering operation in steps S1 and S2 are: operating pressure of 90-120 Pa, temperature of 58℃-65℃, and calendering speed of 150-300 cm / min.

[0010] Preferably, the vulcanization temperatures of the liquid silicone and the solid modified silicone in step S1 are 150-170℃ and 170℃-190℃, respectively.

[0011] Preferably, the covering layer is made of any one of polyester fiber cloth, nylon, aramid, spandex, and glass fiber; the core material is any one of glass fiber composite board, carbon fiber composite board, and aluminum plate.

[0012] The present invention also provides a flap seal, which is prepared by the above-described flap seal preparation method.

[0013] The present invention also provides a wing including the above-described flap seal.

[0014] Compared with the prior art, the preparation method of the flap seal, the flap seal and the wing described in the embodiments of the present invention have the following beneficial effects: 1) The coating layer is treated with liquid silicone to seal the pores on the surface of the coating layer and at the same time, it serves as an adhesive transition layer and is vulcanized with modified silicone to form an integrated structure. The surface of the final product will not produce glue overflow, achieving a self-cleaning effect, thereby improving the dimensional accuracy and pass rate of the product; 2) The polyester fiber fabric is treated with vacuum plasma to clean the surface and increase the bonding strength; at the same time, a coating is set on the surface of the polyester fiber fabric and cured at high temperature, which serves as an adhesive transition layer and is vulcanized with modified silicone to form an integrated structure, further improving the bonding strength of the two to prevent delamination and extending the service life; 3) The silicone is modified by using phenyl, fluoroalkyl end-capping and other methods to disrupt the molecular chain regularity, improve its low-temperature performance, and thus enhance the low-temperature sealing performance of the product. Attached Figure Description

[0015] Figure 1 This is a longitudinal cross-sectional schematic diagram of the flap seal according to an embodiment of the present invention.

[0016] Explanation of reference numerals in the attached figures:

[0017] 1-Core layer; 2-Filling layer; 3-Covering layer. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Without conflict, the technical features of the embodiments of the present invention can be combined with each other. In this application, ordinary silicone refers to silicone of type TR10, and all parts in this application are parts by weight.

[0019] A flap is a movable, wing-shaped device on the edge of a modern aircraft wing, capable of deflecting downwards and / or sliding backwards (forwards) to increase lift during flight. Flap seals are used in conjunction with flaps, and their quality is crucial for lift efficiency. Because silicone sealant is in a viscous state during the high-temperature, high-pressure vulcanization process, it easily overflows from the mesh of the coating layer. This increases friction with the wing, leading to severe wear and affecting product lifespan. Furthermore, cleaning is difficult, resulting in low product yield. This is the problem with flap seals. Figure 1 As shown, this highlights the urgent problems that need to be addressed in the independent domestic production of [the product / service].

[0020] The flap seal includes a core layer 1, with filling layers 2 on the upper and lower sides of the core layer 1, and a covering layer 3 on the side of the filling layer 2 away from the core layer 1. Preferably, the core layer 1, filling layer 2, and covering layer 3 are made of fiberglass board, solid modified silicone, and polyester fiber cloth, respectively. The covering layer 3 includes a first top surface, a connecting surface, and a second top surface connected together. The first and second top surfaces are horizontally positioned above the core layer 1, and the connecting surface is vertically positioned. The connecting surface and the first and second top surfaces are rounded with a radius of 1 mm (R=1 mm). The length of the first top surface is L1-L2=32.77±0.5 mm, and the length of the second top surface is L2=8.13±0.5 mm. The covering layer 3 includes... The system comprises a first bottom surface and a first inclined surface, the first bottom surface being horizontal, and the side of the first inclined surface away from the first bottom surface connecting to the second top surface. The first inclined surface and the first bottom surface have a rounded corner with radius R=0.8mm, and the first inclined surface and the second top surface have a rounded corner with radius R=2.54mm. The height difference between the second top surface and the first bottom surface is 5.07mm. The thicknesses of the core layer 1 and the filling layer 2 are H1=0.8mm and H2=2.53±0.2mm, respectively. The core layer 1 is inclined upwards at the end closest to the second top surface. The length of the flap seal is 1530mm. Before calendering, the combined thickness of the filling layer 2 and the covering layer 3 on one side of the core layer 1 is 1mm. Therefore, the applicant proposes the following technical solution:

[0021] Experimental example: Modification and optimization of solid silica gel

[0022] Ordinary silicone was modified according to the components listed in Table 1. The Shore A hardness, tensile strength, elongation at break, tear strength, low-temperature shrinkage TR10, density, and low-temperature hardness change of the modified silicone were then tested. The results are shown in Table 2. The testing methods for these parameters are existing technologies and will not be described in detail here.

[0023] Table 1 Optimization scheme for solid silica gel modification

[0024]

[0025] Table 2 Performance parameters of different groups of solid modified silica gel

[0026]

[0027] Table 1 shows that the hardness of ordinary silicone increases significantly at low temperatures. Increasing the proportion of phenyl silicone resin can significantly improve the low-temperature curing resistance of silicone, while simply increasing the amount of phenyl vinyl silicone oil cannot improve the low-temperature curing problem and may even lead to a sharp deterioration in performance. The modified solid silicone rubber prepared by using 100 parts of ordinary silicone, 5-20 parts of phenyl vinyl silicone oil, 2-4 parts of phenyl silicone resin, 0.2 parts of HMDS inhibitor, 4 parts of fumed silica, and 1 part of KH550 coupling agent exhibits little change in hardness under extreme low-temperature conditions, which can improve the flight stability of aircraft.

[0028] Example 1

[0029] A method for preparing a flap seal includes the following steps:

[0030] S1, Modification treatment of the coating layer

[0031] Using polyester fiber cloth as the covering layer, the polyester fiber cloth was dried at 100℃ for 2 hours, and then placed in a vacuum plasma device. The vacuum degree was evacuated to 0.1 Pa and stabilized for 3 minutes. The plasma was then applied at 800 cm⁻¹. 3 Oxygen is introduced at a speed of 8 m / min for 120 seconds; then a layer of vinyl silane liquid silicone is coated on the surface of the polyester fiber cloth with a thickness of 0.01 mm. The cloth is then passed through a drying tunnel at 150°C for high-temperature curing and then wound up; the modified coating layer is then calendered on a three-roll calender with a pressure of 100 Pa, a temperature of 60°C, a calendering speed of 200 cm / min, and a thickness of 0.1 mm. After calendering, the cloth is passed through a drying tunnel at a temperature of 180°C for vulcanization and then wound up.

[0032] S2. Calendering treatment of the coating layer and filler layer

[0033] The modified coating layer obtained from S1 and the modified silicone rubber used as the filler layer are calendered on a three-roll calender at an operating pressure of 100 Pa, a temperature of 60 °C, a calendering speed of 200 cm / min, and a thickness of 0.8 mm. The mixture is then rolled up without further vulcanization in the drying tunnel.

[0034] The modified silicone rubber is composed of: 100 parts ordinary silicone rubber, 20 parts phenyl vinyl silicone oil, 2 parts phenyl silicone resin, 0.2 parts HMDS inhibitor, 4 parts fumed silica, and 1 part KH550 coupling agent. It is prepared by the following method: the ordinary silicone rubber is first subjected to open-milling and thin-passing five times. Then, phenyl vinyl silicone oil and inhibitor are added in sequence according to the amount, and the mixture is mixed for 4 minutes. Then, phenyl silicone resin is added in the amount and the mixture is mixed for 6 minutes. Finally, KH550 coupling agent and fumed silica are added in the amount, and the mixture is mixed for 5 minutes. The mixture is then thin-passed five times, sheeted, cooled, and allowed to stand to obtain the final product.

[0035] S3, Compression vulcanization

[0036] The filler layer is wrapped around the top and bottom sides of the core layer, and then placed in a mold for compression molding and vulcanization. The compression molding and vulcanization parameters are: temperature 160℃, time 3 minutes, and pressure 40 kg / cm². 2 That is, you get it.

[0037] Example 2

[0038] A method for preparing a flap seal includes the following steps:

[0039] S1, Modification treatment of the coating layer

[0040] Using polyester fiber cloth as the covering layer, the polyester fiber cloth was dried at 95℃ for 4 hours, and then placed in a vacuum plasma device. The vacuum degree was evacuated to 0.1 Pa and stabilized for 4 minutes. The plasma was then applied at a speed of 1000 cm⁻¹. 3 Oxygen is introduced at a speed of 10 m / min for 60 seconds; then a layer of vinyl silane liquid silicone is coated on the surface of the polyester fiber cloth with a thickness of 0.015 mm. The cloth is then passed through a drying tunnel at 160°C at a speed of 10 m / min for high-temperature curing and then wound up; the modified coating layer is then calendered on a three-roll calender with a modified silicone rubber at an operating pressure of 120 Pa, a temperature of 65°C, a calendering speed of 300 cm / min, and a thickness of 0.15 mm. After calendering, the cloth is passed through a drying tunnel at a temperature of 190°C for vulcanization and then wound up.

[0041] S2. Calendering treatment of the coating layer and filler layer

[0042] The modified coating layer obtained from S1 and the modified silicone rubber used as the filler layer are calendered on a three-roll calender at an operating pressure of 120 Pa, a temperature of 65 ℃, a calendering speed of 300 cm / min, and a thickness of 0.7 mm. They are then rolled up without further vulcanization in the drying tunnel.

[0043] The modified silicone rubber is composed of: 100 parts ordinary silicone rubber, 10 parts phenyl vinyl silicone oil, 5 parts phenyl silicone resin, 0.5 parts HMDS inhibitor, 10 parts fumed silica, and 3 parts KH550 coupling agent. It is prepared by the following method: the ordinary silicone rubber is first subjected to open mixing and thin passing through 4 times. Then, phenyl vinyl silicone oil and inhibitor are added in sequence according to the amount, and mixed for 3 minutes. Then, phenyl silicone resin is added in the amount and mixed for 8 minutes. Finally, KH550 coupling agent and fumed silica are added in the amount, and mixed for 4 minutes. The mixture is then thinly passed through 6 times, sheeted, cooled, and allowed to stand to obtain the final product.

[0044] S3, Compression vulcanization

[0045] The filler layer is wrapped around the top and bottom sides of the core layer, and then placed in a mold for compression molding and vulcanization. The compression molding and vulcanization parameters are: temperature 170℃, time 2min, and pressure 50kg / cm². 2 .

[0046] Example 3

[0047] A method for preparing a flap seal includes the following steps:

[0048] S1, Modification treatment of the coating layer

[0049] Using polyester fiber fabric as the covering layer, the polyester fiber fabric was dried at 105℃ for 1.5 hours, and then placed in a vacuum plasma device. The vacuum degree was evacuated to 0.8 Pa and stabilized for 6 minutes. The plasma was then applied at a speed of 600 cm⁻¹. 3 Oxygen is introduced at a speed of 12 m / min for 90 seconds; then a layer of vinyl silane liquid silicone is coated on the surface of the polyester fiber cloth with a thickness of 0.008 mm. The cloth is then passed through a drying tunnel at 170°C for high-temperature curing and then wound up. The modified polyester fiber cloth is then calendered with modified silicone rubber on a three-roll calender at an operating pressure of 90 Pa, a temperature of 58°C, a calendering speed of 150 cm / min, and a thickness of 0.2 mm. After calendering, the cloth is passed through a drying tunnel at 170°C for vulcanization and then wound up.

[0050] S2. Calendering treatment of the coating layer and filler layer

[0051] The modified polyester fiber cloth obtained from S1 was calendered with modified silicone rubber as a filler layer on a three-roll calender. The operating pressure was 100 Pa, the temperature was 60 ℃, the calendering speed was 200 cm / min, and the thickness was 0.8 mm. It was not vulcanized in the drying tunnel and then wound up.

[0052] The modified silicone rubber is composed of: 100 parts ordinary silicone rubber, 15 parts phenyl vinyl silicone oil, 4 parts phenyl silicone resin, 0.4 parts HMDS inhibitor, 8 parts fumed silica, and 2 parts KH550 coupling agent. It is prepared by the following method: the ordinary silicone rubber is first subjected to open mixing and thin passing through 6 times. Then, phenyl vinyl silicone oil and inhibitor are added in sequence according to the amount, and mixed for 5 minutes. Then, phenyl silicone resin is added in the amount and mixed for 4 minutes. Finally, KH550 coupling agent and fumed silica are added in the amount, and mixed for 3 minutes. The mixture is then thinly passed through 4 times, sheeted, cooled, and allowed to stand to obtain the final product.

[0053] S3, Compression vulcanization

[0054] The filler layer is wrapped around the top and bottom sides of the core layer, and then placed in a mold for compression molding and vulcanization. The compression molding and vulcanization parameters are: temperature 155℃, time 4min, and pressure 30kg / cm². 2 .

[0055] Comparative Example 1

[0056] Commercially available original parts;

[0057] Comparative Example 2

[0058] A method for preparing a flap seal includes the following steps:

[0059] Using polyester fiber cloth as the covering layer, the polyester fiber cloth and ordinary silicone as the filler layer are calendered on a three-roll calender at an operating pressure of 100 Pa, a temperature of 60 ℃, a calendering speed of 200 cm / min, and a thickness of 0.8 mm. No further vulcanization is performed in the drying tunnel, and the roll is then wound up. The filler layer is then wrapped around the upper and lower sides of the core layer and placed in a mold for molding vulcanization to obtain the final product.

[0060] The flap seal prepared in Example 1 and the flap seals of Comparative Examples 1 and 2 were used to measure the width of the second top surface and the thickness of the core layer and the filling layer every 30 mm along the length direction. The specific measurement points and results are shown in Table 3.

[0061] Table 3. Size variation of flap seals from different sources

[0062]

[0063] As shown in Table 3, excess adhesive occupies the width of the second top surface, causing uneven width and thickness, resulting in significant precision errors. The overflowing silicone adheres to the surface, and at extreme low temperatures, the silicone hardens, affecting the sealing effect. It also increases friction with the wing, shortening the product lifespan. Excess adhesive can cause the second top surface to be crushed, affecting the pass rate. The flap seal described in this application can significantly improve the situation of excess adhesive on the surface, improve the cleanliness of the product surface, eliminate the need for manual cleaning, and achieve a high pass rate. At the same time, the width uniformity of the second top surface is good, and the dimensional accuracy is superior to that of imported original parts.

[0064] The flap seals prepared in Example 1 and the flap seals of Comparative Examples 1 and 2 were used to test the peel force between the coating layer and the filler layer. The results are shown in Table 4. At the same time, the surface friction coefficient of the coating layer was tested. Each sample was tested three times and the average value was taken. The results are shown in Table 5. The peel force and friction coefficient were tested in accordance with GB / T 532 and HG / T 2729-2012, respectively.

[0065] Table 4. Peel resistance performance of flap seals from different sources

[0066]

[0067] Table 5. Surface friction coefficients of flap seals from different sources

[0068]

[0069] As shown in Table 4, the average resistance to glass between the covering layer 3 and the filling layer 2 of the flap seal described in this application is 197.39 N, which is 44% higher than that of Comparative Example 1. Meanwhile, the surface friction coefficient of the flap seal described in this application is 0.0324, which is 51.6% lower than that of Comparative Example 1. Clearly, the friction with the wing is low after assembly, resulting in a longer product lifespan. It should be noted that using one of the following—nylon, aramid, spandex, or glass fiber—as the covering layer and carbon fiber composite board or aluminum plate as the core material to prepare the flap seal using the above method will achieve similar results, and will not be elaborated further here.

[0070] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method of preparing a flap seal, characterized in that include: S1. Apply a 0.005-0.015mm thick layer of liquid silicone to the surface of the coating layer and vulcanize it. Then, roll a 0.05-0.15mm thick layer of solid modified silicone on a three-roll calender and vulcanize it to obtain a modified coating layer. S2. Roll a 0.5-1.0mm thick filler layer on the modified coating layer using a three-roll calender. The filler layer is made of solid modified silicone. S3. Wrap the filler layer around the upper and lower sides of the core layer and place it in a mold for molding and vulcanization.

2. The method for preparing the flap seal according to claim 1, characterized in that, The coating layer described in step S1 is pretreated as follows: the coating layer is dried at 95℃-100℃ for 2-4 hours, then placed in a vacuum plasma device and evacuated to 0.1-100 Pa for 3-6 minutes, and then heated at 600-1000 cm⁻¹. 3 Oxygen is introduced at a rate of 1 / min for 120 seconds.

3. The method for preparing the flap seal according to claim 1, characterized in that, The solid modified silica gel comprises: 100 parts ordinary silica gel, 10-20 parts phenyl vinyl silicone oil, 2-5 parts phenyl silicone resin, 0.2-0.5 parts HMDS inhibitor, 4-10 parts fumed silica, and 1-3 parts KH550 coupling agent. It is prepared by the following method: Ordinary silica gel is subjected to open-running and thin-running 4-6 times. Phenyl vinyl silicone oil and inhibitor are added sequentially in the specified amounts, and the mixture is kneaded for 3-5 minutes. Then, phenyl silicone resin is added in the specified amounts and kneaded for 5-8 minutes. Finally, KH550 coupling agent and fumed silica are added in the specified amounts, and the mixture is kneaded for 3-5 minutes. The mixture is then thin-running 4-6 times, sheeted, cooled, and allowed to stand to obtain the final product.

4. The method for preparing the flap seal according to claim 1, characterized in that, The liquid silicone described in step S1 is of the vinyl silane type, and the coating parameters are: a cloth speed of 8-12 m / min.

5. The method for preparing the flap seal according to claim 1, characterized in that, The process parameters for the calendering operation in steps S1 and S2 are: operating pressure of 90-120 Pa, temperature of 58℃-65℃, and calendering speed of 150-300 cm / min.

6. The method for preparing the flap seal according to claim 1, characterized in that, The vulcanization temperatures of the liquid silicone and the solid modified silicone in step S1 are 150-170℃ and 170℃-190℃, respectively.

7. The method for preparing the flap seal according to claim 1, characterized in that, The material of the covering layer is any one of polyester fiber cloth, nylon, aramid, spandex, and glass fiber; the core material is any one of glass fiber composite board, carbon fiber composite board, and aluminum plate.

8. A type of flap sealing mechanism, characterized in that: Prepared by the method for preparing the flap seal according to any one of claims 1-7.

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