A scraping method for silicone rubber coating

Abstract

The present invention relates to a method for scraping silicone rubber coatings, which belongs to the field of surface engineering technology. It solves the technical problem that it is difficult to meet the strict technical requirements of coating thickness and uniformity when scraping silicone rubber coatings on product surfaces using a simple manual method. A method for scraping silicone rubber coatings comprises: step S1: preparing silicone rubber coatings; step S2: designing the total number of scraping layers of silicone rubber coatings on the product surface and the corresponding scraping thickness of each layer according to the coating thickness; step S3: cleaning the surface of the product to be scraped; step S4: pasting and fixing polytetrafluoroethylene film strips on the product surface; step S5: scraping the coating using a polytetrafluoroethylene scraper; step S6: scraping the coating along the spacing area of ​​the coating strips; step S7: pasting polytetrafluoroethylene film strips on the coating surface; step S8: repeating steps S5 to S6; step S9: repeatedly repeating steps S7 to S8; step S10: testing after the coating is dried. The present invention ensures good thermal protection performance of the product.

Description

Technical Field

[0001] The invention belongs to the technical field of surface engineering, and in particular relates to a scraping method for a silicone rubber coating. Background Art

[0002] During long-term, high-speed flight, the outer surface of aerospace products will be continuously exposed to a harsh aerodynamic thermal environment. In order to reduce the impact of hot airflow and high-temperature damage to the internal components of the product caused by the external high-temperature environment during service, ensure the normal operation of the product, and effectively improve the service life and safety of the components, the outer surface of the product must be coated with heat-resistant materials for protection.

[0003] Due to the need for thermal protection, parts of the product that are subject to more stringent thermal environments need to have a heat-resistant coating prepared on the surface. The main component of this heat-resistant coating is silicone rubber. Since the thickness and uniformity of the coating have a significant impact on the thermal protection performance, the coating film thickness is required to be more than 2mm. However, the spraying process has the disadvantage of poor interlayer bonding, so the scraping process needs to be used. However, it is difficult to meet the requirements of coating thickness and uniformity using a simple manual scraping method. Summary of the Invention

[0004] In view of the above analysis, the present invention proposes a method for scraping silicone rubber coating to solve the technical problem that it is difficult to meet the strict technical requirements of coating thickness and uniformity by scraping silicone rubber coating on the product surface using a simple manual method.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] The present invention provides a scraping method for a silicone rubber coating, comprising the following steps:

[0007] Step S1: preparing silicone rubber coating;

[0008] Step S2: Design the total number of scraping layers n and the F of each layer of silicone rubber coating on the product surface according to the coating thickness i Corresponding coating thickness T i Each layer F i The thickness H of the corresponding PTFE film strip used i , width K i ;

[0009] Step S3: Clean the surface of the product to be coated to make it dry and dust-free;

[0010] Step S4: Along the direction of the prepared scraping, PTFE film strips of equal thickness and width are applied and fixed on the surface of the product at intervals. The thickness H1 of the PTFE film strips is equal to the scraping thickness T1 of the first scraping layer F1, and the spacing D1 between adjacent PTFE film strips is equal to the width K1 of the PTFE film strips.

[0011] Step S5: Use a polytetrafluoroethylene scraper to scrape an appropriate amount of silicone rubber coating, place the two edges of the scraper on adjacent polytetrafluoroethylene film strips, and scrape the coating along the spacing area of ​​the polytetrafluoroethylene film strips to obtain a layer of coating strips with uniform spacing and uniform thickness on the product surface;

[0012] Step S6: After the coating is dry, the polytetrafluoroethylene film strips are peeled off and a polytetrafluoroethylene scraper is used to scrape an appropriate amount of silicone rubber coating. The two edges of the scraper are placed on adjacent coating strips and the coating is scraped along the spacing between the coating strips to obtain a first layer F1 coating with a uniform thickness on the product surface.

[0013] Step S7: After the coating is dry, polytetrafluoroethylene film strips of equal thickness and width are applied and fixed to the coating surface along the direction of the scraping. The thickness H2 of the polytetrafluoroethylene film strips is equal to the scraping thickness T2 of the second scraping layer F2, and the spacing D2 between adjacent polytetrafluoroethylene film strips is equal to the width K2 of the polytetrafluoroethylene film strips.

[0014] Step S8: Repeat steps S5 to S6 to obtain a second layer F2 coating with uniform thickness;

[0015] Step S9: Repeat steps S7 to S8 to obtain the i-th layer F with uniform thickness. i Coating, until the nth layer F n coating;

[0016] Step S10: Detection after the coating is dried.

[0017] Furthermore, during the scraping operation, the ambient temperature is controlled at 15° C. to 35° C. and the relative humidity is controlled at 30% to 70%.

[0018] Furthermore, in step S2, the coating thickness is 2 to 3 mm.

[0019] Furthermore, the coating thickness is 3 mm.

[0020] Furthermore, in step S2, each layer F i Corresponding coating thickness T i It is 0.3~0.7mm.

[0021] Furthermore, each layer F i Corresponding coating thickness T i 0.5mm.

[0022] Furthermore, in step S2, the width K of the polytetrafluoroethylene film strip is i The range is 6 to 14 mm.

[0023] Furthermore, the width K of the PTFE film strip i is 10mm.

[0024] Furthermore, in step S6, step S8 and step S9, the coating is dried for 3 to 5 hours.

[0025] Furthermore, the coating was dried for 4 h.

[0026] Compared with the prior art, the present invention can achieve at least one of the following technical effects:

[0027] (1) The present invention obtains a thermal protection coating with a thickness of more than 2 mm and uniformity that meets the requirements by layering the silicone rubber coating, thereby ensuring good thermal protection performance and aesthetics of the product.

[0028] (2) The present invention utilizes the characteristic that polytetrafluoroethylene material is not easy to adhere to silicone rubber coating, uses polytetrafluoroethylene film strips to cover the product surface, and uses a polytetrafluoroethylene scraper to scrape the coating, thereby making the scraping process simple and easy to operate.

[0029] (3) The present invention controls the thickness of a single-layer scraping coating by using a polytetrafluoroethylene (PTFE) film strip, thereby controlling the coating thickness tolerance within a reasonable technical requirement range.

[0030] (4) The present invention ensures that the final surface quality, thickness tolerance and adhesion of the coating meet the technical requirements by designing reasonable process parameters, such as the thickness range of a single layer of scraping and the drying time of the coating.

[0031] (5) The process of the present invention has been successfully applied to a certain research model.

[0032] Other features and advantages of the present invention will be described in the following description, and part of them may become obvious from the description, or may be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings are only for purposes of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference numerals designate like components throughout the drawings.

[0034] Figure 1 Schematic diagrams of the front and top views of the polytetrafluoroethylene film strips attached and fixed to the surface of the product or coating;

[0035] Figure 2 Schematic diagrams of front and top views of scraping paint along the spacing area of ​​the polytetrafluoroethylene film strips;

[0036] Figure 3 Schematic diagrams of scraping the coating along the spacing area of ​​the coating stripe from the front and top;

[0037] In the figure, 1-product or coating surface; 2-i-th layer F i PTFE film strip; 3- coating direction; 4- PTFE scraper; 5- i-th layer F i Coating strip; H i - Scrape down the i-th layer F i The thickness of the front-mounted and fixed polytetrafluoroethylene film strip; K i - Scrape down the i-th layer F i Width of the front-mounted and fixed polytetrafluoroethylene film strip; D i - Scrape down the i-th layer F i The distance between adjacent fixed polytetrafluoroethylene film strips; T i - Layer i F i The coating thickness. DETAILED DESCRIPTION

[0038] The following is a further detailed description of a scraping method for a silicone rubber coating in conjunction with specific examples. These examples are only for comparison and explanation purposes, and the present invention is not limited to these examples.

[0039] The present invention provides a scraping method for a silicone rubber coating, comprising the following steps:

[0040] Step S1: preparing silicone rubber coating;

[0041] Step S2: Design the total number of scraping layers n and the F of each layer of silicone rubber coating on the product surface according to the coating thickness i Corresponding coating thickness T i Each layer F i The thickness H of the corresponding PTFE film strip used i , width K i ;

[0042] Step S3: Clean the surface of the product to be coated to make it dry and dust-free;

[0043] Step S4: Along the direction of the prepared scraping, PTFE film strips of equal thickness and width are applied and fixed on the surface of the product at intervals. The thickness H1 of the PTFE film strips is equal to the scraping thickness T1 of the first scraping layer F1, and the spacing D1 between adjacent PTFE film strips is equal to the width K1 of the PTFE film strips.

[0044] Step S5: Use a polytetrafluoroethylene scraper to scrape an appropriate amount of silicone rubber coating, place the two edges of the scraper on adjacent polytetrafluoroethylene film strips, and scrape the coating along the spacing area of ​​the polytetrafluoroethylene film strips to obtain a layer of coating strips with uniform spacing and uniform thickness on the product surface;

[0045] Step S6: After the coating is dry, the polytetrafluoroethylene film strips are peeled off and a polytetrafluoroethylene scraper is used to scrape an appropriate amount of silicone rubber coating. The two edges of the scraper are placed on adjacent coating strips and the coating is scraped along the spacing between the coating strips to obtain a first layer F1 coating with a uniform thickness on the product surface.

[0046] Step S7: After the coating is dry, polytetrafluoroethylene film strips of equal thickness and width are applied and fixed to the coating surface along the direction of the scraping. The thickness H2 of the polytetrafluoroethylene film strips is equal to the scraping thickness T2 of the second scraping layer F2, and the spacing D2 between adjacent polytetrafluoroethylene film strips is equal to the width K2 of the polytetrafluoroethylene film strips.

[0047] Step S8: Repeat steps S5 to S6 to obtain a second layer F2 coating with uniform thickness;

[0048] Step S9: Repeat steps S7 to S8 to obtain the i-th layer F with uniform thickness. i Coating, until the nth layer F n coating;

[0049] Step S10: Detection after the coating is dried.

[0050] It should be noted that during the scraping operation, the ambient temperature is controlled at 15°C to 35°C and the relative humidity is 30% to 70%.

[0051] Specifically, in step S1, each component of the coating is accurately weighed according to the mass ratio, and a diluent is added and stirred evenly.

[0052] Silicone rubber coatings are composed of component A, component B, and a diluent. Excessive component B can cause the coating to cure too quickly, leading to cracking. Too little can cause the coating to not cure for a long time, or even never, and thus fail to achieve the desired heat-resistant properties. Excessive diluent can result in low viscosity, insufficient thickness for a single coat, and the coating can easily sag. Excessive diluent can result in excessive viscosity, reduced ductility during scraping, difficulty in evenly coating the product surface, and the formation of bubbles, which can affect coating quality.

[0053] It should be noted that in step S2, since the viscosity of the coating is relatively large and the coating thickness is required to be above 2 mm, 2 to 3 mm, preferably 3 mm, in order to make the coating appearance uniform and meet the coating performance, multiple scrapings are required, that is, after one layer of scraping is applied, the surface is dried before the next layer is scraped. Moreover, the thickness of a single layer of scraping also has a certain influence on the coating quality. If the thickness of a single layer of scraping is too thick, the curing agent reaction will be incomplete, and the diluent needs to evaporate from the inside of the coating. If the thickness of a single layer of scraping is too thick, it will cause bubbling and cracking of the coating; if the thickness of a single layer of scraping is too thin, it will affect the efficiency of coating preparation.

[0054] The total number of scraping layers is designed to be n according to the coating thickness and the thickness of a single scraping layer. n is a natural number greater than 1. The i-th layer F i The coating thickness is T i , i is a natural number, i≤n, that is, the scraping thickness of the first layer F1 is T1, the scraping thickness of the second layer F2 is T2, and the scraping thickness of the nth layer F n The coating thickness is T n Specifically, the thickness of a single layer of scraping is T i The coating thickness of each layer is 0.3-0.7 mm, preferably 0.5 mm. i They can be equal or not.

[0055] It should be noted that in steps S4 to S9, the polytetrafluoroethylene material is flexible and not easily damaged, and is not easy to adhere to silicone rubber coating, so a polytetrafluoroethylene film strip is used to cover the product or coating surface, and a polytetrafluoroethylene scraper is used to scrape the coating.

[0056] Specifically, in step S4, step S7 and step S9, before applying the first layer F1, the thickness of the polytetrafluoroethylene film strips fixed on the surface of the product is H1, the width is K1, and the spacing between adjacent polytetrafluoroethylene film strips is D1; ​​before applying the second layer F2, the thickness of the polytetrafluoroethylene film strips fixed on the surface of the coating layer is H2, the width is K2, and the spacing between adjacent polytetrafluoroethylene film strips is D2; when applying the i-th layer F i The thickness of the fixed polytetrafluoroethylene film strips on the front surface is H i , width K i , the distance D between adjacent PTFE film strips i ; Scrape the nth layer F n The thickness of the fixed polytetrafluoroethylene film strips on the front surface is H n , width K n , the distance D between adjacent PTFE film strips n Thickness H of PTFE film strips with different scraping coatings i They can be equal or different, but the thickness H of each layer of PTFE film strip of the scraping coating iMust be equal to the thickness T of the scraped layer i ; Width K of PTFE film strips with different scraping coatings i The distance D between adjacent PTFE film strips of different scraping coatings can be equal or unequal. i Can be equal or different, but the width K of the PTFE film strip of the same scraping coating i The distance D between adjacent PTFE film strips i Must be equal, specifically, K i and D i The range is 6 to 14 mm, preferably 10 mm. In addition, the positions of the polytetrafluoroethylene film strips of different scraping coats can be the same or different. Figure 1 Schematic diagrams of the front and top views of attaching and fixing polytetrafluoroethylene film strips to the surface of a product or coating.

[0057] It should be noted that since the thermal protective coating is only applied to part of the surface of the product, when the polytetrafluoroethylene film strip is applied and fixed to the product surface or the scraping coating surface, the polytetrafluoroethylene film strip can be made longer and extended to the product surface without the thermal protective coating. The two ends of the polytetrafluoroethylene film strip are fixed with tape on the product surface without the thermal protective coating. In addition, the polytetrafluoroethylene film strip itself has a certain adsorption property, so when the two ends are fixed, it can be better applied to the product surface or the coating surface.

[0058] It should be noted that in steps S5, S6, S8 and S9, the width K of the polytetrafluoroethylene film strip of each scraping layer is i , the distance D between adjacent PTFE film strips i The width of the working surface of the PTFE scraper must be smaller than that of the K i =D i =100mm, and the width of the PTFE scraper working surface is 160mm. During scraping, the scraper moves at a constant speed to ensure that the scraper is closely attached to the surface of the PTFE film or coating strip. The scraped coating is thicker and the direction of scraping is easier to control. The coating thickness prepared by scraping is the same as that of the PTFE film or coating strip. Figure 2 Schematic diagrams of front and top views of scraping paint along the spacing area of ​​the polytetrafluoroethylene film strips; Figure 3 Schematic diagrams of scraping the coating along the spacing area of ​​the coating stripe from the front and top;

[0059] It should be noted that in step S6 and steps S8 to S9, the drying time of the coating has a certain influence on the quality of the coating. If the drying time is too short, the reaction of component B in the silicone rubber coating will be incomplete. If the drying time is too long, the coating will be initially solidified, and the thickness and viscosity of the adjacent coating to be scraped off next time will be too different from that of the coating. The adjacent coating to be scraped off next time will be difficult to completely fill the gap of the initially solidified coating, thereby affecting the overall heat resistance of the coating. In addition, a long drying time reduces the preparation efficiency of the coating. Specifically, the drying time of the coating is 3 to 5 hours, that is, the interval between waiting for the coating to dry and two adjacent scrapings is 3 to 5 hours, preferably 4 hours.

[0060] Specifically, in step S10, the coating surface quality and adhesion test are performed on the dried coating. The coating surface is required to be flat, without defects such as cracks, delamination, blistering, peeling, looseness, etc., and without protrusions or pits with a height or depth greater than 0.5 mm. The coating thickness tolerance and the thickness of the single-layer scraping T i Correlation, controlled within ±0.6T avg Within, T avg The coating thickness is divided by the total number of scraping layers n, and the adhesion is not less than 0.5Mpa.

[0061] Example 1

[0062] To prepare a 2mm thick silicone rubber coating on an aviation product, the silicone rubber grade is TR-42. The steps are as follows:

[0063] Step S1: preparing silicone rubber coating;

[0064] Step S2: According to the coating thickness, the total number of scraping layers of silicone rubber coating on the product surface is 4 layers, and each layer F i Corresponding coating thickness T i All are 0.5mm, each layer F i The thickness H of the corresponding PTFE film strip used i All are 0.5mm, width K i All are 10mm;

[0065] Step S3: Clean the surface of the product to be coated to make it dry and dust-free;

[0066] Step S4: Along the direction of the prepared scraping, PTFE film strips of equal thickness and width are applied and fixed on the surface of the product at intervals. The thickness H1 of the PTFE film strips is equal to the scraping thickness T1 of the first scraping layer F1, and the spacing D1 between adjacent PTFE film strips is equal to the width K1 of the PTFE film strips.

[0067] Step S5: Use a polytetrafluoroethylene scraper to scrape an appropriate amount of silicone rubber coating, place the two edges of the scraper on adjacent polytetrafluoroethylene film strips, and scrape the coating along the spacing area of ​​the polytetrafluoroethylene film strips to obtain a layer of coating strips with uniform spacing and uniform thickness on the product surface;

[0068] Step S6: After the coating has dried for 4 hours, the polytetrafluoroethylene film strips are peeled off and an appropriate amount of silicone rubber coating is scraped off using a polytetrafluoroethylene scraper. The two edges of the scraper are placed on adjacent coating strips and the coating is scraped off along the spacing between the coating strips to obtain a first layer F1 coating of uniform thickness on the product surface.

[0069] Step S7: After the coating has dried for 4 hours, polytetrafluoroethylene film strips of equal thickness and width are applied and fixed to the coating surface along the direction of the scraping. The thickness H2 of the polytetrafluoroethylene film strips is equal to the scraping thickness T2 of the second scraping layer F2, and the spacing D2 between adjacent polytetrafluoroethylene film strips is equal to the width K2 of the polytetrafluoroethylene film strips.

[0070] Step S8: Repeat steps S5 to S6 to obtain a second layer F2 coating with uniform thickness;

[0071] Step S9: Repeat steps S7 to S8 twice to obtain a third layer F3 coating with uniform thickness, until a fourth layer F4 coating is obtained;

[0072] Step S10: Detection after the coating is dried, see Table 1.

[0073] Example 2

[0074] To prepare a 3mm thick silicone rubber coating on an aviation product, the silicone rubber grade is TR-42. The steps are as follows:

[0075] Step S1: preparing silicone rubber coating;

[0076] Step S2: According to the coating thickness, the total number of scraping layers of silicone rubber coating on the product surface is 6 layers, and each layer F i Corresponding coating thickness T i All are 0.5mm, each layer F i The thickness H of the corresponding PTFE film strip used i All are 0.5mm, width K i All are 10mm;

[0077] Step S3: Clean the surface of the product to be coated to make it dry and dust-free;

[0078] Step S4: Along the direction of the prepared scraping, PTFE film strips of equal thickness and width are applied and fixed on the surface of the product at intervals. The thickness H1 of the PTFE film strips is equal to the scraping thickness T1 of the first scraping layer F1, and the spacing D1 between adjacent PTFE film strips is equal to the width K1 of the PTFE film strips.

[0079] Step S5: Use a polytetrafluoroethylene scraper to scrape an appropriate amount of silicone rubber coating, place the two edges of the scraper on adjacent polytetrafluoroethylene film strips, and scrape the coating along the spacing area of ​​the polytetrafluoroethylene film strips to obtain a layer of coating strips with uniform spacing and uniform thickness on the product surface;

[0080] Step S6: After the coating has dried for 4 hours, the polytetrafluoroethylene film strips are peeled off and an appropriate amount of silicone rubber coating is scraped off using a polytetrafluoroethylene scraper. The two edges of the scraper are placed on adjacent coating strips and the coating is scraped off along the spacing between the coating strips to obtain a first layer F1 coating of uniform thickness on the product surface.

[0081] Step S7: After the coating has dried for 4 hours, polytetrafluoroethylene film strips of equal thickness and width are applied and fixed to the coating surface along the direction of the scraping. The thickness H2 of the polytetrafluoroethylene film strips is equal to the scraping thickness T2 of the second scraping layer F2, and the spacing D2 between adjacent polytetrafluoroethylene film strips is equal to the width K2 of the polytetrafluoroethylene film strips.

[0082] Step S8: Repeat steps S5 to S6 to obtain a second layer F2 coating with uniform thickness;

[0083] Step S9: Repeat steps S7 to S8 four times to obtain the third layer F3 coating, the fourth layer F4 coating, the fifth layer F5 coating, and finally the sixth layer F6 coating with uniform thickness.

[0084] Step S10: Detection after the coating is dried, see Table 1.

[0085] Example 3

[0086] To prepare a 3mm thick silicone rubber coating on an aviation product, the silicone rubber grade is TR-42. The steps are as follows:

[0087] Step S1: preparing silicone rubber coating;

[0088] Step S2: Design the total number of scraping layers of silicone rubber coating on the product surface according to the coating thickness, which is 10 layers. i Corresponding coating thickness T i All are 0.3mm, each layer F i The thickness H of the corresponding PTFE film strip used i All are 0.3mm, width K i All are 6mm;

[0089] Step S3: Clean the surface of the product to be coated to make it dry and dust-free;

[0090] Step S4: Along the direction of the prepared scraping, PTFE film strips of equal thickness and width are applied and fixed on the surface of the product at intervals. The thickness H1 of the PTFE film strips is equal to the scraping thickness T1 of the first scraping layer F1, and the spacing D1 between adjacent PTFE film strips is equal to the width K1 of the PTFE film strips.

[0091] Step S5: Use a polytetrafluoroethylene scraper to scrape an appropriate amount of silicone rubber coating, place the two edges of the scraper on adjacent polytetrafluoroethylene film strips, and scrape the coating along the spacing area of ​​the polytetrafluoroethylene film strips to obtain a layer of coating strips with uniform spacing and uniform thickness on the product surface;

[0092] Step S6: After the coating has dried for 3 hours, the polytetrafluoroethylene film strips are peeled off and an appropriate amount of silicone rubber coating is scraped off using a polytetrafluoroethylene scraper. The two edges of the scraper are placed on adjacent coating strips and the coating is scraped off along the spacing between the coating strips to obtain a first layer F1 coating of uniform thickness on the product surface.

[0093] Step S7: After the coating has dried for 3 hours, polytetrafluoroethylene film strips of equal thickness and width are applied and fixed to the coating surface along the direction of the scraping. The thickness H2 of the polytetrafluoroethylene film strips is equal to the scraping thickness T2 of the second scraping layer F2, and the spacing D2 between adjacent polytetrafluoroethylene film strips is equal to the width K2 of the polytetrafluoroethylene film strips.

[0094] Step S8: Repeat steps S5 to S6 to obtain a second layer F2 coating with uniform thickness;

[0095] Step S9: Repeat steps S7 to S8 eight times to obtain the 3rd layer F3 coating, the 4th layer F4 coating, the 5th layer F5 coating, the 6th layer F6 coating, the 7th layer F7 coating, the 8th layer F8 coating, the 9th layer F9 coating with uniform thickness, until the 10th layer F 10 coating;

[0096] Step S10: Detection after the coating is dried, see Table 1.

[0097] Example 4

[0098] Prepare a 3mm thick silicone rubber coating on an aerospace product. The silicone rubber grade is TR-42. The steps are as follows:

[0099] Step S1: preparing silicone rubber coating;

[0100] Step S2: Design the total number of scraping layers of the silicone rubber coating on the surface of the product according to the coating thickness to be 5 layers. The scraping thicknesses T1, T2, and T3 corresponding to the first layer F1, the second layer F2, and the third layer F3 are all 0.7 mm. The thicknesses H1, H2, and H3 of the polytetrafluoroethylene film strips used for the first layer F1, the second layer F2, and the third layer F3 are all 0.7 mm, and the widths K1, K2, and K3 are all 14 mm. The scraping thickness T4 corresponding to the fourth layer F4 is 0.5 mm. The thickness H4 of the polytetrafluoroethylene film strip used for the fourth layer F4 is 0.5 mm, and the width K4 is 14 mm. The scraping thickness T5 corresponding to the fifth layer F5 is 0.4 mm. The thickness H5 of the polytetrafluoroethylene film strip used for the fifth layer F5 is 0.4 mm, and the width K5 is 14 mm.

[0101] Step S3: Clean the surface of the product to be coated to make it dry and dust-free;

[0102] Step S4: Along the direction of the prepared scraping, PTFE film strips of equal thickness and width are applied and fixed on the surface of the product at intervals. The thickness H1 of the PTFE film strips is equal to the scraping thickness T1 of the first scraping layer F1, and the spacing D1 between adjacent PTFE film strips is equal to the width K1 of the PTFE film strips.

[0103] Step S5: Use a polytetrafluoroethylene scraper to scrape an appropriate amount of silicone rubber coating, place the two edges of the scraper on adjacent polytetrafluoroethylene film strips, and scrape the coating along the spacing area of ​​the polytetrafluoroethylene film strips to obtain a layer of coating strips with uniform spacing and uniform thickness on the product surface;

[0104] Step S6: After the coating has dried for 5 hours, the polytetrafluoroethylene film strips are peeled off and an appropriate amount of silicone rubber coating is scraped off using a polytetrafluoroethylene scraper. The two edges of the scraper are placed on adjacent coating strips and the coating is scraped off along the spacing between the coating strips to obtain a first layer F1 coating of uniform thickness on the product surface.

[0105] Step S7: After the coating has dried for 5 hours, polytetrafluoroethylene film strips of equal thickness and width are applied and fixed to the coating surface along the direction of the scraping. The thickness H2 of the polytetrafluoroethylene film strips is equal to the scraping thickness T2 of the second scraping layer F2, and the spacing D2 between adjacent polytetrafluoroethylene film strips is equal to the width K2 of the polytetrafluoroethylene film strips.

[0106] Step S8: Repeat steps S5 to S6 to obtain a second layer F2 coating with uniform thickness;

[0107] Step S9: Repeat steps S7 to S8 three times to obtain a third layer F3 coating, a fourth layer F4 coating, and finally a fifth layer F5 coating with uniform thickness.

[0108] Step S10: Detection after the coating is dried, see Table 1.

[0109] Example 5

[0110] To prepare a 2.5mm thick silicone rubber coating on an aerospace product, the silicone rubber grade is TR-42. The steps are as follows:

[0111] Step S1: preparing silicone rubber coating;

[0112] Step S2: Design the total number of scraping layers of silicone rubber coating on the product surface according to the coating thickness, which is 5 layers. i Corresponding coating thickness T i All are 0.5mm, each layer F i The thickness H of the corresponding PTFE film strip used i All are 0.5mm, width K i All are 10mm;

[0113] Step S3: Clean the surface of the product to be coated to make it dry and dust-free;

[0114] Step S4: Along the direction of the prepared scraping, PTFE film strips of equal thickness and width are applied and fixed on the surface of the product at intervals. The thickness H1 of the PTFE film strips is equal to the scraping thickness T1 of the first scraping layer F1, and the spacing D1 between adjacent PTFE film strips is equal to the width K1 of the PTFE film strips.

[0115] Step S5: Use a polytetrafluoroethylene scraper to scrape an appropriate amount of silicone rubber coating, place the two edges of the scraper on adjacent polytetrafluoroethylene film strips, and scrape the coating along the spacing area of ​​the polytetrafluoroethylene film strips to obtain a layer of coating strips with uniform spacing and uniform thickness on the product surface;

[0116] Step S6: After the coating has dried for 4 hours, the polytetrafluoroethylene film strips are peeled off and an appropriate amount of silicone rubber coating is scraped off using a polytetrafluoroethylene scraper. The two edges of the scraper are placed on adjacent coating strips and the coating is scraped off along the spacing between the coating strips to obtain a first layer F1 coating of uniform thickness on the product surface.

[0117] Step S7: After the coating has dried for 4 hours, polytetrafluoroethylene film strips of equal thickness and width are applied and fixed to the coating surface along the direction of the scraping. The thickness H2 of the polytetrafluoroethylene film strips is equal to the scraping thickness T2 of the second scraping layer F2, and the spacing D2 between adjacent polytetrafluoroethylene film strips is equal to the width K2 of the polytetrafluoroethylene film strips.

[0118] Step S8: Repeat steps S5 to S6 to obtain a second layer F2 coating with uniform thickness;

[0119] Step S9: Repeat steps S7 to S8 three times to obtain a third layer F3 coating, a fourth layer F4 coating, and finally a fifth layer F5 coating with uniform thickness.

[0120] Step S10: Detection after the coating is dried, see Table 1.

[0121] Comparative Example 1

[0122] A silicone rubber coating with a thickness of 3 mm was prepared on an aviation product. The silicone rubber grade was TR-42. According to the coating thickness, the total number of scraping layers of silicone rubber coating on the product surface was 3 layers. Each layer of F i Corresponding coating thickness T i All are 1.0mm, each layer F i The thickness H of the corresponding PTFE film strip used i All are 1.0mm, width K i The thickness of the coating is 10 mm, and the rest is exactly the same as in Example 2. The coating is tested after drying, as shown in Table 1.

[0123] Comparative Example 2

[0124] A silicone rubber coating with a thickness of 3 mm was prepared on an aviation product. The silicone rubber grade was TR-42. The coating was dried for 2 hours, and the other conditions were exactly the same as in Example 2. The coating was tested after drying, as shown in Table 1.

[0125] Comparative Example 3

[0126] A silicone rubber coating with a thickness of 3 mm was prepared on an aviation product. The silicone rubber grade was TR-42. Except for the coating drying time of 6 hours, the other conditions were exactly the same as those in Example 2. The coating was tested after drying, as shown in Table 1.

[0127] Table 1 Coating test results of Examples 1 to 5 and Comparative Examples 1 to 3

[0128]

[0129] From the test results in Table 1, it can be seen that the apparent quality, bonding strength and coating thickness tolerance of Examples 1 to 5 are all within the required range, while the bonding strength of Comparative Examples 1 to 3 is lower than 0.5 MPa, and the apparent quality of Comparative Examples 1 to 2 is unqualified.

[0130] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for scraping a silicone rubber coating, characterized in that: The steps include: Step S1: preparing silicone rubber coating; Step S2: Design the total number of scraping layers n and the F of each layer of silicone rubber coating on the product surface according to the coating thickness i Corresponding coating thickness T i Each layer F i The thickness H of the corresponding PTFE film strip used i , width K i Each layer F i Corresponding coating thickness T i 0.3~0.7mm; Step S3: Clean the surface of the product to be coated to make it dry and dust-free; Step S4: Along the direction of the prepared scraping, PTFE film strips of equal thickness and width are applied and fixed on the surface of the product at intervals. The thickness H1 of the PTFE film strips is equal to the scraping thickness T1 of the first scraping layer F1, and the spacing D1 between adjacent PTFE film strips is equal to the width K1 of the PTFE film strips. Step S5: Use a polytetrafluoroethylene scraper to scrape an appropriate amount of silicone rubber coating, place the two edges of the scraper on adjacent polytetrafluoroethylene film strips, and scrape the coating along the spacing area of ​​the polytetrafluoroethylene film strips to obtain a layer of coating strips with uniform spacing and uniform thickness on the product surface; Step S6: After the coating is dry, the polytetrafluoroethylene film strips are peeled off and a polytetrafluoroethylene scraper is used to scrape an appropriate amount of silicone rubber coating. The two edges of the scraper are placed on adjacent coating strips and the coating is scraped along the spacing between the coating strips to obtain a first layer F1 coating with a uniform thickness on the product surface. Step S7: After the coating is dry, polytetrafluoroethylene film strips of equal thickness and width are applied and fixed to the coating surface along the direction of the scraping. The thickness H2 of the polytetrafluoroethylene film strips is equal to the scraping thickness T2 of the second scraping layer F2, and the spacing D2 between adjacent polytetrafluoroethylene film strips is equal to the width K2 of the polytetrafluoroethylene film strips. Step S8: Repeat steps S5 to S6 to obtain a second layer F2 coating with uniform thickness; Step S9: Repeat steps S7 to S8 to obtain the i-th layer F with uniform thickness. i Coating, until the nth layer F n coating; Step S10: Inspection after the coating is dried; the coating surface must be flat, without cracks, delamination, blistering, peeling, loose defects, and no protrusions or pits with a height or depth greater than 0.5 mm; the coating thickness tolerance and the thickness of the single layer scraping T i Correlation, controlled within ±0.6T avg Within, T avg The coating thickness is divided by the total number of scraping layers n; the adhesion is not less than 0.5Mpa; In the steps S5, S6, S8 and S9, the width K of the polytetrafluoroethylene film strip of each scraping coating layer is i , the distance D between adjacent polytetrafluoroethylene film strips i are all smaller than the width of the working surface of the polytetrafluoroethylene scraper; In step S6, step S8 and step S9, the coating is dried for 3 to 5 hours.

2. The method according to claim 1, characterized in that During scraping operation, the ambient temperature should be controlled at 15℃~35℃ and the relative humidity should be 30%~70%.

3. The method according to claim 1, characterized in that In step S2, the coating thickness is 2 to 3 mm.

4. The method according to claim 3, characterized in that The coating thickness is 3 mm.

5. The method according to claim 1, wherein Each layer F i Corresponding coating thickness T i 0.5mm.

6. The method according to claim 1, characterized in that In step S2, the width K of the polytetrafluoroethylene film strip is i The range is 6 to 14 mm.

7. The method according to claim 6, characterized in that The width K of the polytetrafluoroethylene film strip i is 10mm.

8. The method according to claim 1, characterized in that The coating was dried for 4 hours.

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