A high-temperature-resistant shielding paste for hot-dip galvanizing and a preparation method thereof

Abstract

The application discloses a high-temperature-resistant shielding patch for hot galvanizing and a preparation method thereof, and belongs to the technical field of metal surface treatment auxiliary materials. The shielding patch is sequentially provided with a release layer, a rubber shielding layer and a high-temperature-resistant base material layer from top to bottom. The rubber shielding layer mainly comprises isobutylene-isoprene copolymer, and is compounded with polyisobutylene, high-temperature-resistant resin and softening agent, and is matched with high-temperature-resistant fillers, heat-resistant stabilizers, compounded antioxidants and a silane coupling agent system. The finished product is obtained through dense mixing, extrusion and calendering, hot pressing, slitting and winding. The high-temperature-resistant shielding patch for hot galvanizing and the preparation method thereof have the advantages that the formula and the layered structure are optimized, the shielding patch can be adapted to the working condition of hot galvanizing at 440-465 DEG C, does not flow and deform at high temperature, has excellent anti-seepage effect, can be closely attached to complex structures such as threaded holes, flange sealing surfaces and irregular curved surfaces, has no residual glue when being torn off, has excellent salt spray resistance, the process is simple, the cost performance is high, and the shielding patch is suitable for large-scale industrialized popularization and application.

Description

Technical Field

[0001] This invention relates to the field of auxiliary materials for metal surface treatment, and in particular to a high-temperature resistant masking film for hot-dip galvanizing and its preparation method. Background Technology

[0002] Hot-dip galvanizing is the mainstream anti-corrosion treatment process for steel structural components, widely used in infrastructure, machinery, steel structures, and other fields. Its normal operating temperature is maintained between 440℃ and 465℃. Under this condition, the molten zinc liquid has the characteristics of high fluidity, high surface activity, and strong corrosiveness. Therefore, areas of the workpiece that do not need to be coated, such as threaded holes, flange sealing surfaces, and irregular curved surfaces, must be reliably shielded and protected. Otherwise, zinc seepage and misplating problems are very likely to occur, affecting the assembly accuracy of the workpiece and the quality of the finished product. Therefore, high-temperature resistant, highly adaptable, and highly sealing shielding materials are key auxiliary materials for the industrial production of hot-dip galvanizing.

[0003] Currently, the hot-dip galvanizing masking materials in the industry have significant technical shortcomings, making them unsuitable for harsh working conditions. Conventional rubber and plastic masking tapes have extremely poor heat resistance, easily melting, flowing, and deforming in high-temperature environments above 440℃, completely losing their masking and barrier functions, leading to incorrect plating of non-plated areas of the workpiece. At the same time, traditional colloidal materials are prone to decomposition at high temperatures, leaving a large amount of adhesive residue on the workpiece surface after operation, requiring manual grinding and secondary cleaning, significantly increasing process costs and severely reducing mass production efficiency. Existing high-end high-temperature resistant masking products mostly use polyimide film and pure silicone rubber materials. Although they have a certain degree of high-temperature resistance, the material procurement and production costs are extremely high, and the materials themselves have high hardness and poor flexibility. They do not fit tightly and have poor sealing for complex structures such as threaded holes, flange sealing surfaces, and irregular curved surfaces, allowing high-temperature zinc liquid to easily seep through the gaps, resulting in a low masking yield rate and failing to meet the needs of large-scale, high-quality industrial production.

[0004] In summary, current masking materials generally suffer from core drawbacks such as poor high-temperature stability, insufficient adhesion and sealing, easy residue buildup, high production costs, and poor adaptability. None of the products can simultaneously achieve a comprehensive performance balance of high-temperature resistance and leak prevention, good adhesion, no residue, and low cost. Therefore, developing a high-temperature resistant masking film that is suitable for the high-temperature conditions of hot-dip galvanizing, has stable structural performance, provides good adhesion and sealing on complex curved surfaces, leaves no residue after removal, and is economically viable is a pressing technical challenge in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature resistant masking sticker for hot-dip galvanizing and its preparation method, in order to solve the above-mentioned problems.

[0006] This invention provides a high-temperature resistant masking film for hot-dip galvanizing, which consists of a release layer, a rubber masking layer, and a high-temperature resistant substrate layer arranged sequentially from top to bottom. The rubber shielding layer is prepared from the following raw materials in parts by weight: 100 parts isobutylene-isoprene copolymer, 30-50 parts polyisobutylene, 40-60 parts high-temperature resistant tackifying resin, 15-25 parts high-temperature resistant softener, 130-200 parts composite high-temperature resistant filler, 8-15 parts reinforcing carbon black, 5-10 parts heat-resistant stabilizer, 0.5-1.5 parts antioxidant, and 0.5-1 part silane coupling agent.

[0007] Preferably, the heat stabilizer is a compound mixture of magnesium oxide and zinc oxide, with a mass ratio of magnesium oxide to zinc oxide of 1:1.

[0008] Preferably, the high-temperature resistant tackifying resin is a terpene phenolic resin or a hydrogenated C9 petroleum resin, and the high-temperature resistant softener is a polyalphaolefin oil or a hydrogenated naphthenic oil.

[0009] Preferably, the reinforcing carbon black is reinforcing carbon black N774, and the silane coupling agent is KH-550 silane coupling agent.

[0010] Preferably, the antioxidant is a compound system composed of antioxidant 1010 and BHT.

[0011] Preferably, the composite high-temperature resistant filler comprises the following components by weight: 80-120 parts of nano-kaolin, 50-80 parts of wollastonite powder, and 5-10 parts of fumed silica.

[0012] Preferably, the high-temperature resistant substrate layer is made of fiberglass cloth or aluminum foil composite PET material, the thickness of the high-temperature resistant substrate layer is 0.15-0.3mm, and the extreme temperature resistance is not less than 500℃.

[0013] Preferably, the release layer is silicone release paper or fluorine release film.

[0014] A method for preparing a high-temperature resistant masking film for hot-dip galvanizing as described above is provided, comprising the following steps: S1. Internal mixing: Add isobutylene-isoprene copolymer and polyisobutylene to a closed rubber mixing mill and mix at 120°C for 5 minutes; then add composite high-temperature resistant filler, reinforcing carbon black, and silane coupling agent, and continue mixing for 8 minutes; finally add high-temperature resistant tackifying resin, high-temperature resistant softener, heat resistant stabilizer, and antioxidant, and mix for 15-20 minutes until the materials are evenly mixed. S2. Extrusion and calendering: The uniformly mixed rubber compound is fed into an extruder for shaping, and then pressed into a continuous rubber sheet by a calender. S3. Hot-press lamination: The adhesive sheet is bonded to the high-temperature resistant substrate layer and hot-pressed at a temperature of 110°C and a pressure of 0.5MPa to achieve a tight bond between the layers. S4. Post-processing and molding: A release layer is bonded to the surface of the adhesive layer after hot-pressing and lamination. After slitting and winding, the finished product of the high-temperature resistant masking tape for hot-dip galvanizing is obtained.

[0015] Preferably, the thickness of the calendered adhesive sheet in step S2 is 1.2 to 2.0 mm.

[0016] Therefore, the present invention, employing the above-mentioned high-temperature resistant masking sticker for hot-dip galvanizing and its preparation method, has the following beneficial effects: (1) It adopts a three-layer composite structure of release layer, rubber shielding layer and high temperature resistant substrate layer, combined with a specific ratio of heat resistant stabilizer, antioxidant and composite high temperature resistant filler system. The substrate layer is made of glass fiber cloth or aluminum foil composite PET material with a temperature resistance of not less than 500℃, and the skeleton has extremely strong support. The product can withstand a high temperature of 480℃ for a short time. Under the conventional hot-dip galvanizing conditions of 440℃~465℃, the rubber shielding layer does not melt, flow, deform or break, and maintains an intact shielding structure throughout the process. It solves the problems of high temperature failure and misplating of workpieces of traditional rubber and plastic shielding stickers, and has extremely strong adaptability to working conditions.

[0017] (2) By limiting the ratio of composite high-temperature resistant fillers made of nano-kaolin, wollastonite powder, and fumed silica, and with the synergistic effect of N774 reinforcing carbon black, a dense and stable microscopic barrier network is constructed inside the rubber shielding layer, which significantly reduces the wettability and permeability of the high-temperature molten zinc liquid to the colloidal surface. At the same time, based on the high flexibility of the isobutylene-isoprene copolymer and polyisobutylene composite system, the shielding tape can be tightly fitted to complex workpiece structures such as threaded holes, flange sealing surfaces, and irregular curved surfaces, solving the defects of large gaps and zinc liquid leakage in traditional hard high-temperature shielding materials, and effectively preventing zinc seepage and misplating in non-plating areas.

[0018] (3) By selecting high-temperature resistant tackifying resins such as terpene phenolic resin / hydrogenated C9 petroleum resin and high-temperature resistant softeners such as poly-α-olefin oil / hydrogenated naphthenic oil, combined with KH-550 silane coupling agent and a compound antioxidant system, the adhesive bonding performance and high-temperature stability of the colloid are precisely controlled. After the hot-dip galvanizing operation is completed and the workpiece cools down, the masking sticker can be completely peeled off and removed. There is no residual adhesive, no stringing, and no adhesive residue on the workpiece surface. No manual grinding and cleaning is required, which simplifies the production process, significantly improves the efficiency of mass production, and is suitable for industrial assembly line operations.

[0019] (4) The hot-pressing composite process at 110℃ and 0.5MPa ensures tight bonding between the structural layers and prevents delamination. Simultaneously, the heat-resistant stabilizer (1:1 mixture of magnesium oxide and zinc oxide), antioxidant 1010, and BHT effectively enhance the colloid's aging and corrosion resistance. The finished product can withstand over 500 hours of salt spray testing and exhibits no delamination, aging, or cracking during long-term storage. Its service life and stability are far superior to traditional shielding materials.

[0020] (5) Compared with high-cost high-temperature shielding materials such as polyimide and pure silicone rubber, the main raw materials, fillers and additives used in this invention are all conventional industrial raw materials with low procurement costs. At the same time, the preparation process of this invention, including mixing, extrusion calendering, hot pressing and compounding, slitting and winding, is simple and controllable, without the need for complex equipment and special process conditions. The overall production cost can be reduced, and the comprehensive economic efficiency is excellent. It has strong market promotion value and mass industrial application prospects.

[0021] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0022] To better understand the above technical solutions, a detailed description of the specific implementation methods will be provided below. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0024] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0025] All embodiments and comparative samples of this invention uniformly adopt a layered structure consisting of a release layer, a rubber shielding layer, and a high-temperature resistant substrate layer, sequentially laminated from top to bottom. The high-temperature resistant substrate layer is uniformly made of aluminum foil composite PET material, with a thickness of 0.2 mm and an extreme temperature resistance of not less than 500℃. The release layer is uniformly made of fluorinated release film. All samples were tested under the same working conditions and equipment to ensure parallel and comparable data. The specific unified testing standards are as follows: 1. High-temperature hot-dip galvanizing test: The sample is attached to the surface of the steel structure workpiece and placed in a 465℃ high-temperature furnace for 5 minutes. After being taken out and air-cooled to room temperature, the sample is observed to see if there is any flow, deformation, shrinkage, damage or peeling. Check the zinc penetration and misplating in the non-plating areas of the workpiece. 2. Adhesion performance test: Under normal temperature conditions, the initial tack was tested according to GB / T 4852-2002 standard for pressure-sensitive adhesives, and the 180° peel strength was tested according to GB / T 2792-2014 standard. The sample width was uniformly 25mm, and the peel speed was 300mm / min. 3. Residual adhesive peeling performance test: After the hot-dip galvanizing high-temperature condition is completed and the workpiece is naturally cooled to room temperature, the peeling sample is wiped at a uniform speed with a dust-free gauze, and the workpiece surface is visually and microscopically observed to see if there is any residual adhesive, adhesive threads, or adhesive marks. 4. Salt spray aging test: According to GB / T 10125-2021 neutral salt spray test standard, spray continuously for 500 hours and observe whether the sample shows delamination, bubbling, powdering, corrosion, cracking or peeling.

[0026] Example 1 Raw material ratio (parts by weight): 100 parts isobutylene-isoprene copolymer, 40 parts polyisobutylene, 50 parts terpene phenolic resin, 20 parts polyα-olefin oil, 100 parts nano-kaolin, 60 parts wollastonite powder, 8 parts fumed silica, 10 parts reinforcing carbon black N774, 4 parts magnesium oxide, 4 parts zinc oxide, 0.8 parts antioxidant 1010, 0.2 parts antioxidant BHT, 0.8 parts silane coupling agent KH-550.

[0027] Among them, the heat-resistant stabilizer is composed of magnesium oxide and zinc oxide in a mass ratio of 1:1; the composite high-temperature resistant filler is composed of nano-kaolin, wollastonite powder and fumed silica; the high-temperature resistant tackifying resin is terpene phenolic resin; the high-temperature resistant softener is polyalphaolefin oil; and the antioxidant is a compound system of antioxidant 1010 and BHT.

[0028] Preparation process: S1, Internal mixing: Isobutylene-isoprene copolymer and polyisobutylene are put into a closed rubber mixing mill, the temperature is set to 120℃, and the mixture is mixed for 5 minutes; then nano kaolin, wollastonite powder, fumed silica, reinforcing carbon black N774, and silane coupling agent KH-550 are added, and the mixture is continued to be mixed for 8 minutes; finally, terpene phenolic resin, polyα-olefin oil, magnesium oxide, zinc oxide, antioxidant 1010, and antioxidant BHT are added, and the mixture is mixed for 15-20 minutes until the materials are evenly mixed.

[0029] S2. Extrusion and calendering: The mixed rubber compound is fed into an extruder for shaping, and then calendered into a continuous rubber sheet with a thickness of 1.5 mm. The thickness of the rubber layer is controlled within the preferred range of 1.2 to 2.0 mm.

[0030] S3. Hot-press lamination: The prepared adhesive sheet is bonded to the high-temperature resistant substrate layer and hot-pressed at a temperature of 110℃ and a pressure of 0.5MPa to ensure tight interlayer bonding and no delamination gaps.

[0031] S4. Post-processing and molding: A fluorine release film is laminated onto the adhesive layer surface, and after slitting and winding, the finished high-temperature resistant masking film for hot-dip galvanizing is obtained.

[0032] Performance test results: High temperature resistance: After 5 minutes of exposure to 465℃, the product showed no dripping, deformation, or damage, and the overall structure remained stable. Adhesion performance: Initial tack at room temperature was 14.2N / 25mm, and peel strength at 180° was 18.5N / 25mm, demonstrating strong adhesion and tight fit. Leakage prevention performance under working conditions: No zinc seepage or misplating occurred during hot-dip galvanizing. Peeling effect: After the workpiece cooled to room temperature, the masking tape could be completely removed with gauze, leaving the workpiece surface clean with no adhesive residue or stringing. Salt spray resistance: After 500 hours of continuous salt spray testing, the adhesive layer remained tightly bonded to the workpiece and substrate, showing no detachment, corrosion, or aging / powdering. Compatibility with complex structures: It can be tightly fitted to flange sealing surfaces, threaded holes, and irregular curved surfaces, providing excellent sealing performance.

[0033] Example 2 Raw material ratio (parts by weight): 100 parts isobutylene-isoprene copolymer, 40 parts polyisobutylene, 50 parts hydrogenated C9 petroleum resin, 20 parts hydrogenated naphthenic oil, 90 parts nano-kaolin, 65 parts wollastonite powder, 7 parts fumed silica, 12 parts reinforcing carbon black N774, 4.5 parts magnesium oxide, 4.5 parts zinc oxide, 1.0 part antioxidant 1010, 0.3 parts antioxidant BHT, and 0.7 parts silane coupling agent KH-550.

[0034] Preparation process: The preparation process is completely the same as in Example 1, and the thickness of the calendered adhesive layer is controlled to be 1.8 mm.

[0035] Performance test results: High temperature resistance: After 5 minutes of exposure to 465℃, the sample showed no flow, shrinkage, deformation, or breakage, and the overall structure remained stable. Adhesion performance: Initial tack at room temperature was 13.8 N / 25 mm, and peel strength at 180° was 17.9 N / 25 mm, indicating strong adhesion. Working condition anti-seepage performance: No zinc seepage or misplating occurred in non-plated areas of the workpiece under hot-dip galvanizing conditions. Peeling effect: The gauze could be completely peeled off after cooling, leaving the workpiece surface clean with no residual adhesive or stringing. Salt spray resistance: After 500 hours of neutral salt spray testing, there was no delamination, blistering, powdering, or corrosion. Compatibility with complex structures: The flange sealing surface, threaded holes, and irregular curved surfaces fit tightly without gaps, providing excellent sealing performance and meeting the requirements of large-scale industrial hot-dip galvanizing production.

[0036] Example 3 Raw material ratio (parts by weight): 100 parts isobutylene-isoprene copolymer, 30 parts polyisobutylene, 40 parts hydrogenated C9 petroleum resin, 15 parts hydrogenated naphthenic oil, 80 parts nano-kaolin, 50 parts wollastonite powder, 5 parts fumed silica, 48 parts reinforcing carbon black N77, 2.5 parts magnesium oxide, 2.5 parts zinc oxide, 0.4 parts antioxidant 1010, 0.1 parts antioxidant BHT, and 0.5 parts silane coupling agent KH-550.

[0037] Preparation process: The preparation process is completely the same as in Example 1, and the thickness of the calendered adhesive layer is controlled to be 1.2 mm.

[0038] Performance test results: High temperature resistance: After being kept at 465℃ for 5 minutes, the sample showed slight softening without dripping, significant deformation, or breakage and detachment, indicating a basically stable structure. Adhesion performance: Initial tack at room temperature was 12.5 N / 25 mm, and peel strength at 180° was 16.3 N / 25 mm, demonstrating reliable adhesion. Working condition anti-seepage performance: No significant zinc seepage or misplating issues were observed under hot-dip galvanizing conditions. Peeling effect: Complete peeling was achieved after cooling, with no obvious residual adhesive on the workpiece surface. Salt spray resistance: After a 500-hour neutral salt spray test, no delamination, corrosion, or cracking issues were observed, with only very slight powdering at the edges. All performance characteristics meet the standards for hot-dip galvanizing production and use.

[0039] Comparative Example 1 It uses commercially available hot-dip galvanized ordinary rubber and plastic masking tape, without special composite high-temperature resistant fillers, heat-resistant and stable compound systems, or special high-temperature resistant additive systems. The manufacturing process is the same as that used for commercially available masking tapes.

[0040] High temperature resistance: After holding at 465℃ for 2 minutes, obvious softening, flowing, and local detachment occur; after 5 minutes, complete failure and inability to be masked occur. Adhesion performance: Initial tack at room temperature is 8.6N / 25mm, peel strength at 180° is 10.2N / 25mm; adhesion fails and degumming occurs after high temperature. Working condition anti-seepage performance: Large areas of zinc seepage and misplating occur in non-plated areas of the workpiece, and masking completely fails. Peeling effect: After high temperature cooling, large areas of residual adhesive and adhesive threads adhere to the surface of the workpiece, requiring manual grinding and cleaning. Salt spray resistance: Obvious degumming, aging, and powdering occur after 200h neutral salt spray test; unable to withstand long-term corrosive working conditions.

[0041] Comparative Example 2 Based on Example 1, the composite filler of nano-kaolin, wollastonite powder, and fumed silica was completely replaced with an equal amount of ordinary calcium carbonate as a single filler, while the other raw material components and proportions remained unchanged. The preparation process was the same as in Example 1.

[0042] High temperature resistance: After holding at 465℃ for 5 minutes, the sample softened significantly and shrank in volume, with a substantial decrease in the density of the colloid; Adhesion performance: Initial tack at room temperature was 10.3 N / 25 mm, and peel strength at 180° was 12.8 N / 25 mm. Adhesion stability decreased after high temperature; Working condition seepage prevention performance: Localized pinpoint zinc seepage appeared on the workpiece, indicating insufficient shielding and sealing; Peeling effect: After peeling, pinpoint trace amounts of residual adhesive remained on the workpiece surface, requiring simple wiping and cleaning; Salt spray resistance performance: After 500 hours of salt spray testing, the colloid surface showed slight powdering, the bonding interface weakened, and the aging and corrosion resistance was significantly inferior to the composite filler system in Example 1.

[0043] Comparative Example 3 Based on Example 1, the mass ratio of magnesium oxide to zinc oxide was adjusted to 2:1, the total weight of the heat stabilizer remained unchanged, and the remaining components and proportions remained the same. The preparation process was the same as in Example 1.

[0044] High temperature resistance: After holding at 465℃ for 5 minutes, the heat resistance stability of the colloid decreased, the surface became sticky, and slight deformation occurred; Adhesion performance: Initial tack at room temperature was 11.2 N / 25 mm, and peel strength at 180° was 14.1 N / 25 mm. The adhesion strength decreased significantly after high temperature; Working condition seepage prevention performance: Trace zinc seepage points appeared in some gaps of the workpiece; Peeling effect: Slight residual adhesive traces were found in some areas, and the cleanliness decreased; Salt spray resistance performance: After 500 hours of salt spray test, the sample showed slight discoloration and decreased interfacial bonding strength. The weather resistance and thermal stability deteriorated significantly. A 1:1 mixture of magnesium oxide and zinc oxide can form the best heat resistance synergy effect. Deviating from this ratio will reduce the product's high temperature resistance and anti-aging performance.

[0045] Comparative Example 4 The masking film is made of commercially available industrial-grade pure silicone rubber and is free of isobutylene-isoprene copolymer as the main adhesive and matching high-temperature resistant additives and fillers.

[0046] High temperature resistance: After holding at 465℃ for 5 minutes, there was no melting, flowing, or breakage, indicating good high temperature resistance. Adhesion performance: Initial tack at room temperature is 9.5N / 25mm, and peel strength at 180° is 11.6N / 25mm, indicating weak overall adhesion. Waterproofing performance under working conditions: The shielding effect on flat workpieces is acceptable, but there are obvious gaps on flange sealing surfaces, threaded holes, and irregular curved surfaces, resulting in high zinc liquid leakage and low shielding yield. Peeling effect: No residue or glue threads after peeling. Salt spray resistance: No corrosion or delamination was observed during a 500-hour salt spray test, indicating excellent weather resistance. However, the material has high hardness and poor flexibility, resulting in poor adaptability to complex working conditions, high raw material costs, and poor economic efficiency for mass production.

[0047] A comparison of the parallel control test data of Examples 1-3 and Comparative Examples 1-4 shows that: Examples 1-3 exhibit excellent and stable performance data. Under the high-temperature conditions of hot-dip galvanizing at 465℃, the structure does not flow or deform, possesses excellent high-temperature anti-seepage shielding ability, moderate bonding strength, and is suitable for complex workpiece structures such as flange sealing surfaces, threaded holes, and irregular curved surfaces. After peeling, there is no residual adhesive on the workpiece, and it can stably withstand 500h salt spray aging test, making it suitable for large-scale industrial continuous production.

[0048] Comparative Example 1: Traditional ordinary rubber and plastic masking tape has extremely poor high-temperature resistance, easily melts and flows at high temperatures, completely fails to mask, and leaves significant residue and poor weather resistance, making it unsuitable for the harsh conditions of hot-dip galvanizing. Comparative Example 2: After replacing the composite high-temperature resistant filler system of this invention with a single filler, the density of the colloid decreased, and the high-temperature impermeability, adhesion stability, and aging resistance were all significantly reduced, proving that the specific compound filler system of this invention is the key to ensuring high-temperature barrier performance. Comparative Example 3: After deviating from the 1:1 heat-resistant and stable ratio of magnesium oxide and zinc oxide, the high-temperature thermal stability and anti-aging performance of the colloid were significantly reduced. Comparative Example 4: Although existing high-end pure silicone rubber masking products have acceptable high-temperature resistance and weather resistance, their material flexibility is poor, their complex structure results in insufficient sealing, high leakage risk, and significantly higher production costs, making their overall adaptability and economy far inferior to this invention.

[0049] Therefore, this invention employs the aforementioned high-temperature resistant masking sticker for hot-dip galvanizing and its preparation method. It utilizes a three-layer composite structure consisting of a release layer, a rubber masking layer, and a high-temperature resistant substrate layer, combined with a specific ratio of heat-resistant stabilizers, antioxidants, and a composite high-temperature resistant filler system. The substrate layer is made of fiberglass cloth or aluminum foil composite PET material with a temperature resistance of not less than 500℃, providing extremely strong structural support. The product can withstand short-term high temperatures of 480℃. Under conventional hot-dip galvanizing conditions of 440℃ to 465℃, the rubber masking layer does not melt, flow, deform, or break, maintaining a complete masking structure throughout the process. This solves the problems of high-temperature failure and misplating of workpieces associated with traditional rubber and plastic masking stickers, demonstrating excellent adaptability to various working conditions.

[0050] By limiting the ratio of composite high-temperature resistant fillers made from nano-kaolin, wollastonite powder, and fumed silica, and combining them with the synergistic effect of N774 reinforcing carbon black, a dense and stable microscopic barrier network is constructed within the rubber masking layer, significantly reducing the wettability and penetration of molten zinc on the colloidal surface. Simultaneously, based on the high flexibility of the isobutylene-isoprene copolymer and polyisobutylene composite system, the masking tape can tightly adhere to complex workpiece structures such as threaded holes, flange sealing surfaces, and irregular curved surfaces, solving the defects of large gaps and zinc leakage in traditional rigid high-temperature masking materials, effectively preventing zinc seepage and misplating in non-plating areas. By selecting high-temperature resistant tackifying resins such as terpene phenolic resin / hydrogenated C9 petroleum resin and high-temperature softening agents such as polyα-olefin oil / hydrogenated naphthenic oil, combined with KH-550 silane coupling agent and a compound antioxidant system, the adhesive properties and high-temperature stability of the colloidal material are precisely controlled. After the hot-dip galvanizing process is completed and the workpiece cools down, the masking sticker can be completely peeled off and removed. There is no residual adhesive, no stringing, and no adhesive residue on the workpiece surface. No manual grinding or cleaning is required, which simplifies the production process, significantly improves the efficiency of mass production, and is suitable for industrial assembly line operations.

[0051] The hot-pressing composite process at 110℃ and 0.5MPa ensures a tight bond between the structural layers, preventing delamination and detachment. Simultaneously, a 1:1 mixture of magnesium oxide and zinc oxide as a heat-resistant stabilizer, along with an antioxidant 1010 and BHT compound system, effectively enhances the colloid's aging and corrosion resistance. The finished product can withstand over 500 hours of salt spray testing and exhibits no delamination, aging, or cracking during long-term storage. Its service life and stability far surpass those of traditional shielding materials.

[0052] Compared to high-cost high-temperature shielding materials such as polyimide and pure silicone rubber, the main raw materials, fillers, and additives used in this invention are all conventional industrial raw materials, resulting in low procurement costs. At the same time, the preparation process of this invention, which involves mixing, extrusion calendering, hot pressing, slitting, and winding, is simple and controllable, requiring no complex equipment or special process conditions. This reduces overall production costs, resulting in excellent comprehensive economic benefits and strong market promotion value and prospects for mass industrial application.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-temperature resistant masking film for hot-dip galvanizing, characterized in that, From top to bottom, a release layer, a rubber shielding layer, and a high-temperature resistant substrate layer are sequentially composited. The rubber shielding layer is prepared from the following raw materials in parts by weight: 100 parts isobutylene-isoprene copolymer, 30-50 parts polyisobutylene, 40-60 parts high-temperature resistant tackifying resin, 15-25 parts high-temperature resistant softener, 130-200 parts composite high-temperature resistant filler, 8-15 parts reinforcing carbon black, 5-10 parts heat-resistant stabilizer, 0.5-1.5 parts antioxidant, and 0.5-1 part silane coupling agent.

2. The high-temperature resistant masking film for hot-dip galvanizing according to claim 1, characterized in that, The heat stabilizer is a compound mixture of magnesium oxide and zinc oxide, with a mass ratio of magnesium oxide to zinc oxide of 1:

1.

3. The high-temperature resistant masking film for hot-dip galvanizing according to claim 1, characterized in that, The high-temperature resistant tackifying resin is a terpene phenolic resin or a hydrogenated C9 petroleum resin, and the high-temperature resistant softener is a polyalphaolefin oil or a hydrogenated naphthenic oil.

4. The high-temperature resistant masking film for hot-dip galvanizing according to claim 1, characterized in that, The reinforcing carbon black is reinforcing carbon black N774, and the silane coupling agent is KH-550 silane coupling agent.

5. The high-temperature resistant masking film for hot-dip galvanizing according to claim 1, characterized in that, The antioxidant is a compound system composed of antioxidant 1010 and BHT.

6. The high-temperature resistant masking film for hot-dip galvanizing according to claim 1, characterized in that, The composite high-temperature resistant filler comprises the following components by weight: 80-120 parts of nano-kaolin, 50-80 parts of wollastonite powder, and 5-10 parts of fumed silica.

7. The high-temperature resistant masking film for hot-dip galvanizing according to claim 1, characterized in that, The high-temperature resistant substrate layer is made of fiberglass cloth or aluminum foil composite PET material, the thickness of the high-temperature resistant substrate layer is 0.15-0.3mm, and the extreme temperature resistance is not less than 500℃.

8. The high-temperature resistant masking film for hot-dip galvanizing according to claim 1, characterized in that, The release layer is silicone release paper or fluorine release film.

9. A method for preparing a high-temperature resistant masking film for hot-dip galvanizing as described in any one of claims 1-8, characterized in that, The steps include the following: S1. Internal mixing: Add isobutylene-isoprene copolymer and polyisobutylene to a closed rubber mixing mill and mix at 120°C for 5 minutes; then add composite high-temperature resistant filler, reinforcing carbon black, and silane coupling agent, and continue mixing for 8 minutes; finally add high-temperature resistant tackifying resin, high-temperature resistant softener, heat resistant stabilizer, and antioxidant, and mix for 15-20 minutes until the materials are evenly mixed. S2. Extrusion and calendering: The uniformly mixed rubber compound is fed into an extruder for shaping, and then pressed into a continuous rubber sheet by a calender. S3. Hot-press lamination: The adhesive sheet is bonded to the high-temperature resistant substrate layer and hot-pressed at a temperature of 110°C and a pressure of 0.5MPa to achieve a tight bond between the layers. S4. Post-processing and molding: A release layer is bonded to the surface of the adhesive layer after hot-pressing and lamination. After slitting and winding, the finished product of the high-temperature resistant masking tape for hot-dip galvanizing is obtained.

10. The method for preparing a high-temperature resistant masking film for hot-dip galvanizing according to claim 9, characterized in that, The thickness of the calendered adhesive sheet in step S2 is 1.2 to 2.0 mm.