Sealing adhesive tape as well as preparation method and application thereof

Abstract

The invention relates to the field of sealing materials, in particular to a sealing adhesive tape and a preparation method and application thereof. The sealing adhesive tape structurally comprises an isolating layer and a sealing adhesive layer located on the surface of the isolating layer, and main raw materials of the sealing adhesive layer comprise organic silicon resin, organic silicon modified resin, polyimide resin, a heat stabilizer, reinforced fibers, filler, MQ resin and the like. The finally prepared sealing adhesive tape not only has excellent high-temperature resistance, but also can keep excellent initial adhesion in a high-temperature environment, and ensures that no air leakage phenomenon occurs in the pre-pumping and using processes; and on the other hand, it can be ensured that excellent sealing performance is kept in the vacuum autoclave forming process at the temperature of 427 DEG C, the adhesive residue phenomenon is greatly reduced in the follow-up removing process, good removability and low odor are kept, the requirement for the performance of the sealing adhesive tape in the prior art is effectively met, and wide application potential is achieved.

Description

Technical Field

[0001] The present application relates to the field of sealing materials, and more specifically to a sealing tape and a preparation method and application thereof. Background Art

[0002] With the development of material science, new composite materials have been widely used in the field of aviation materials in recent years because of their higher strength, modulus and fatigue resistance than metal materials such as steel, aluminum and titanium. The preparation process of new composite materials requires the use of vacuum high-temperature hot pressing (usually hot pressing in a vacuum autoclave), among which sealing tape is an important preparation auxiliary material. It is used to maintain vacuum under high temperature environment in this step and is the most important quality assurance method to ensure that composite materials have no defects such as pores.

[0003] In recent years, with the continuous research on the above-mentioned new composite materials, especially with the application of high-performance materials such as polyimide (PI) with high heat resistance and high strength in composite materials, the vacuum high-temperature hot pressing molding temperature of new composite materials has gradually increased from the initial 120~200℃ to the current 300~427℃. Therefore, the performance requirements for the auxiliary materials of sealing tape used to ensure the vacuum environment are also constantly increasing. The sealing tape needs to meet the sealing performance requirements under the existing high molding temperature, and during the molding process, the sealing tape also needs to be vulcanized at a matching speed in the program temperature rise, so that it can withstand the internal and external pressure difference to maintain the internal vacuum. However, existing sealing tape auxiliary materials generally have the following performance problems: 1. The initial adhesion or overall adhesion is not enough, and air leakage is prone to occur during the pre-extraction process and use process in the preparation process of new composite materials, especially in the high-pressure stage, where the air leakage is more obvious; 2. The sealing performance is reduced at high temperatures, and the vacuum pressure holding capacity is insufficient; 3. Multiple properties of the sealing tape are prone to performance contradictions, and there is too much residual glue in the cooling stage after use, resulting in more cleaning burdens and increased costs in the process. Summary of the invention

[0004] Furthermore, how to effectively solve the problems existing in the above-mentioned prior art has become an inevitable topic for researchers in this field. In order to effectively solve the above-mentioned problems, the present applicant has studied and provided a sealing tape and a method for preparing the same. The sealing tape finally prepared by the present application not only has excellent high temperature resistance, but also can maintain excellent initial adhesion in a high temperature environment, ensuring that there is no leakage during pre-extraction and use; on the other hand, it can also ensure excellent sealing in the vacuum autoclave molding process at 427°C, and greatly reduce the residual glue phenomenon in the subsequent cleaning process, maintain good removability and low odor, effectively meet the performance requirements of the prior art for sealing tapes, and has broad application potential.

[0005] The sealing tape comprises an isolation layer and a sealing layer located on the surface of the isolation layer.

[0006] As a preferred implementation, the thickness of the isolation layer is 0.05-0.2 mm.

[0007] As a more preferred embodiment, the thickness of the isolation layer is 0.08-0.15 mm.

[0008] As a preferred implementation, the isolation layer is high temperature resistant release paper.

[0009] As a preferred implementation, the thickness of the sealant layer is 1.5-3.5 mm.

[0010] As a more preferred embodiment, the thickness of the sealant layer is 2-3 mm.

[0011] As a preferred embodiment, the sealant layer is composed of the following components, measured by mass: 35 to 82 parts of silicone resin, 2 to 4 parts of silicone modified resin, 4 to 8 parts of polyimide resin, 2 to 5 parts of heat stabilizer, 1 to 3 parts of reinforcing fiber, 10 to 30 parts of filler, 5 to 10 parts of MQ resin, 4 to 10 parts of silicone oil, 1 to 3 parts of self-healing agent, and 1 to 3 parts of vulcanizing agent.

[0012] As a preferred embodiment, the organic silicone resin is a composition of phenyl vinyl silicone rubber resin and modified octamethylcyclotetrasiloxane resin.

[0013] As a preferred embodiment, the mass ratio of the phenyl vinyl silicone rubber resin to the modified octamethylcyclotetrasiloxane resin is (30-70): (5-12).

[0014] As a preferred embodiment, the mass ratio of the phenyl vinyl silicone rubber resin to the modified octamethylcyclotetrasiloxane resin is (35-50): (8-10).

[0015] As a preferred embodiment, the number average molecular weight Mn of the phenyl vinyl silicone rubber resin is 550,000 to 650,000 Da.

[0016] As a more preferred embodiment, the number average molecular weight Mn of the phenyl vinyl silicone rubber resin is 600,000 to 620,000 Da.

[0017] As a preferred embodiment, the phenyl content of the phenyl vinyl silicone rubber resin is 14-20 mol %, and the vinyl content is 0.1-0.4 mol %.

[0018] As a more preferred embodiment, the phenyl content of the phenyl vinyl silicone rubber resin is 15-17 mol %, and the vinyl content is 0.2-0.3 mol %.

[0019] As a preferred embodiment, the preparation method of the modified octamethylcyclotetrasiloxane resin specifically comprises the following steps: S1: octamethylcyclotetrasiloxane, phenyltrimethoxysilane, vinyltriethoxysilane, trifluoropropylmethylcyclotrisiloxane, and γ-glycidyloxypropyltrimethoxysilane are sequentially added into a reaction kettle, stirred at a speed of 50-70 rpm and deionized water is slowly added, then glacial acetic acid is added dropwise to adjust the pH of the system to 4-4.5, and the temperature is raised to 45-50° C. and stirred at a speed of 200-250 rpm for 2-3 hours to obtain a premix; S2: Add tetramethylammonium hydroxide to the premix, stir evenly at a speed of 150-180 rpm, then heat to 80-85°C, control the vacuum pressure to -0.09-0.08 MPa, dehydrate for 1.5-2 hours, then heat to 110-115°C, keep warm for 6-7 hours to obtain a preproduct; S3: keep the preproduct at 145-150°C for 30-40 minutes, and protect with nitrogen, then cool to 120-125°C to remove low-boiling substances, and naturally cool to room temperature after completion, and take out the product and wash it through a 300-400 mesh sieve to obtain it.

[0020] As a preferred embodiment, the mass ratio of octamethylcyclotetrasiloxane, phenyltrimethoxysilane, vinyltriethoxysilane, trifluoropropylmethylcyclotrisiloxane, and γ-glycidyloxypropyltrimethoxysilane is (10-11): (3-3.5): (1-1.2): (1.8-2): (0.6-0.8).

[0021] As a preferred embodiment, the mass ratio of octamethylcyclotetrasiloxane, phenyltrimethoxysilane, vinyltriethoxysilane, trifluoropropylmethylcyclotrisiloxane, and γ-glycidyloxypropyltrimethoxysilane is 10.5:3.3:1.2:1.8:0.7.

[0022] The addition of modified octamethylcyclotetrasiloxane resin can effectively improve the high temperature resistance, adhesion and sealing properties of the sealing tape. The modified octamethylcyclotetrasiloxane resin is not easy to break at high temperatures due to the high bond energy and thermal stability of the phenyl group, forming a rigid network skeleton, inhibiting the thermal motion of the molecular chain, greatly limiting the thermal decomposition efficiency of the material, and inhibiting the molecular chain breakage phenomenon at high temperatures through the high bond energy of the Si-O bond, and forming a more stable internal three-dimensional cross-linked network through the cross-linking effect of the vinyl group, thereby increasing the interaction between the molecular chains and enhancing the resistance to molecular chain slippage. Furthermore, through the excellent rotational freedom of the molecular chain segments, it can adapt to the thermal deformation caused by high temperatures above 400°C, and inhibit the oxidation chain reaction through the excellent capture effect of free radicals, thereby greatly enhancing the high temperature resistance, adhesion and sealing stability of the sealing tape in a high temperature environment above 400°C, and the silicon hydroxyl groups on the surface of the silicone rubber form hydrogen bonds or chemical bonds with the substrate, significantly improving the initial adhesion of the tape.

[0023] As a preferred embodiment, the organosilicon-modified resin is an organosilicon-modified polyimide resin.

[0024] As a preferred embodiment, the melt index MI of the silicone-modified polyimide resin is 8-14 g / 10 min (295° C. / 6.6 kgf).

[0025] As a preferred embodiment, the glass transition temperature Tg of the silicone-modified polyimide resin is 160-200°C.

[0026] As a preferred embodiment, the polyimide resin is thermoplastic polyimide resin powder.

[0027] As a preferred embodiment, the glass transition temperature Tg of the thermoplastic polyimide resin powder is 300-350°C.

[0028] As a preferred embodiment, the D50 average particle size of the thermoplastic polyimide resin powder is 15-25 μm.

[0029] As a preferred embodiment, the thermal stabilizer is cerium oxide powder or ferric oxide powder or a combination thereof.

[0030] As a preferred embodiment, the thermal stabilizer is cerium oxide powder or ferric oxide powder.

[0031] As a preferred embodiment, the thermal stabilizer is a composition of cerium oxide powder and ferric oxide powder in a mass ratio of (2.5-3):2.

[0032] As a preferred embodiment, the reinforcing fiber is glass fiber or aramid chopped fiber.

[0033] As a preferred embodiment, the reinforcing fibers have an average diameter of 10-14 μm and an average length of 1-3 mm.

[0034] As a preferred embodiment, the filler is a composition of silicon dioxide and aluminum hydroxide.

[0035] As a preferred embodiment, the mass ratio of silicon dioxide to aluminum hydroxide is (2-10):(5-20).

[0036] As a more preferred embodiment, the mass ratio of silicon dioxide to aluminum hydroxide is (3-7): (10-20).

[0037] As a preferred embodiment, the MQ resin is a vinyl MQ resin.

[0038] As a preferred embodiment, the vinyl content of the vinyl MQ resin is 2-3 wt %.

[0039] As a preferred embodiment, the silicone oil is a composition of vinyl-terminated phenyl silicone oil and hydroxy silicone oil.

[0040] As a preferred embodiment, the mass ratio of the terminal vinyl phenyl silicone oil to the hydroxy silicone oil is (2-4): (2-4).

[0041] As a more preferred embodiment, the mass ratio of the terminal vinyl phenyl silicone oil to the hydroxy silicone oil is 4:3.

[0042] As a preferred embodiment, the phenyl content of the vinyl-terminated phenyl silicone oil is 28-30 mol%.

[0043] As a preferred embodiment, the hydroxyl content of the hydroxy silicone oil is 8-10wt%.

[0044] As a preferred embodiment, the self-healing agent is boric acid or boric acid ester.

[0045] As a more preferred embodiment, the self-healing agent is boric acid.

[0046] As a preferred embodiment, the vulcanizing agent is an organic peroxide or a platinum vulcanizing agent.

[0047] As a more preferred embodiment, the vulcanizing agent is an organic peroxide.

[0048] The preparation method of the sealing tape specifically comprises the following steps: S1: putting silicone resin, silicone modified resin, polyimide resin, heat stabilizer, reinforcing fiber and filler into a kneader for one kneading, stirring at a material temperature of 190-210°C for 2-4 hours, and after completion, tabletting and detecting that there are no particles, cooling the discharged material to below 80°C to obtain an intermediate; S2: putting MQ resin, silicone oil and self-healing agent into a high-speed mixer, stirring at 175-185°C and a vacuum degree of -0.10-0.09Mpa for 2-3 hours to obtain a tackifying composition; S3: mixing the intermediate and the tackifying composition The mixture is sequentially put into a kneading machine for secondary kneading, stirred at a material temperature of 190-210°C for 0.5-1.5h, and naturally cooled to room temperature after completion to obtain a base material; S4: The base material is added between the double rollers of an open mixing mill with a cooling function, and a vulcanizing agent is added after thinning for 3-5 times, and the thinning is continued for 3-5 times. The temperature of the whole process is controlled at 50-60°C, and after uniform mixing, a sheet is produced to obtain a sealing rubber compound; S5: The sealing rubber compound is fed into an extruder, the material temperature is controlled at 70-80°C, extruded onto the unwinding isolation layer and formed into a sealing rubber layer through a roller press, and after completion, it is rolled up and cut to obtain a sealing tape of a desired size.

[0049] In the present application, based on the compound addition of specific silicone resin, silicone modified resin and polyimide resin in the raw materials of the sealant layer, they can form a sealing resin system with excellent adhesion to the PI film after effective vulcanization, and greatly enhance its compatibility with other raw materials through multi-group and branched structure, so that the sealing tape can effectively improve its mechanical properties and mechanical stability during application, which is beneficial to the sealing effect and subsequent easy removal; on the other hand, during the preparation process, the sealing resin system and the added tackifying composition system can be compounded to jointly improve the initial adhesion and high temperature resistance, while forming a reversible coordination bond with BO bonds as the main body, greatly improving the product's easy removal and heat-resistant sealing performance.

[0050] The present application further defines the application of the above-mentioned sealing tape in the preparation process of high-performance composite materials for aviation.

[0051] The beneficial effects of this application are: 1. A sealing tape provided in the present application not only has excellent high temperature resistance, but also can maintain excellent initial adhesion in a high temperature environment, ensuring that there is no leakage during pre-extraction and use; on the other hand, it can also ensure excellent sealing in the vacuum autoclave molding process at 427°C, and greatly reduce residual glue in the subsequent cleaning process, maintain good removability and low odor, effectively meet the performance requirements of the existing technical field for sealing tapes, and have broad application potential.

[0052] 2. A sealing tape provided in the present application is not easy to break at high temperatures by adding modified octamethylcyclotetrasiloxane resin, and forms a rigid network skeleton, which inhibits the thermal motion of molecular chains and greatly limits the thermal decomposition efficiency of the material. The high bond energy of Si-O bonds inhibits the breakage of molecular chains at high temperatures, and forms a more stable internal three-dimensional cross-linked network through the cross-linking effect of vinyl groups, thereby increasing the interaction force between molecular chains and enhancing resistance to molecular chain slippage. Furthermore, through the excellent rotational freedom of molecular chain segments, it can adapt to thermal deformation caused by high temperatures above 400°C, and inhibits oxidative chain reactions through the excellent capture effect of free radicals, thereby greatly enhancing the high temperature resistance, adhesion and sealing stability of the sealing tape in high temperature environments above 400°C.

[0053] 3. A sealing tape provided in the present application is based on the compound addition of specific silicone resin, silicone modified resin and polyimide resin in the raw materials of the sealant layer, which can together form a sealing resin system with excellent adhesion to the PI film after effective vulcanization, and greatly enhances its compatibility with other raw materials through multi-group and branched structure, so that the sealing tape can effectively improve its mechanical properties and mechanical stability during application, which is beneficial to the sealing effect and subsequent ease of removal. DETAILED DESCRIPTION

[0054] In the specific implementation manner, specific implementation cases will be used to more intuitively display and illustrate the contents of the invention content of this application.

[0055] In the following examples, unless otherwise specified, the raw materials are all commercially available products, or can be prepared by methods well known to those skilled in the art.

[0056] Example 1 The sealing tape comprises an isolation layer and a sealing layer on the surface of the isolation layer; the thickness of the isolation layer is 0.1 mm, the isolation layer is high temperature resistant release paper, and the product model 10002 is purchased from Shanghai Lianguan Packaging Technology Co., Ltd. in China; the thickness of the sealing layer is 3 mm.

[0057] The sealant layer is composed of the following components, calculated by mass: 45 parts of silicone resin, 2 parts of silicone modified resin, 6 parts of polyimide resin, 5 parts of heat stabilizer, 3 parts of reinforcing fiber, 27 parts of filler, 10 parts of MQ resin, 7 parts of silicone oil, 3 parts of self-healing agent, and 2 parts of vulcanizing agent.

[0058] The organic silicone resin is a composition of phenyl vinyl silicone rubber resin and modified octamethylcyclotetrasiloxane resin, with a mass ratio of 35:10.

[0059] The phenyl vinyl silicone rubber resin has a number average molecular weight Mn of 610,000 Da, a phenyl content of 17 mol %, and a vinyl content of 0.3 mol %. It was purchased from the DT-1122 model product sold by Datian Chemical Additives Research Institute in Panshi City, China.

[0060] The preparation method of modified octamethylcyclotetrasiloxane resin, by mass, specifically comprises the following steps: S1: 10.5 parts of octamethylcyclotetrasiloxane, 3.3 parts of phenyltrimethoxysilane, 1.2 parts of vinyltriethoxysilane, 1.8 parts of trifluoropropylmethylcyclotrisiloxane, and 0.7 parts of γ-glycidyloxypropyltrimethoxysilane are sequentially added into a reaction kettle, stirred at 60 rpm and 40 parts of deionized water are slowly added, then glacial acetic acid is added dropwise to adjust the pH of the system to 4.3, and the temperature is raised to 50°C and the speed is 200 rpm. Stir and react for 2 hours to obtain a premix; S2: add 0.08 parts of tetramethylammonium hydroxide to the premix, stir evenly at 160 rpm, then heat to 85°C, control the vacuum pressure to -0.09 MPa, dehydrate for 1.5 hours, then heat to 110°C, keep warm and react for 6 hours to obtain a preproduct; S3: keep the preproduct at 150°C for 35 minutes, and protect with nitrogen, then cool to 120°C to remove low-boiling substances, and naturally cool to room temperature after completion, and take out the product and wash it through a 350-mesh sieve to obtain it.

[0061] The organosilicon-modified resin is an organosilicon-modified polyimide resin having a melt index MI of 12 g / 10 min (295° C. / 6.6 kgf) and a glass transition temperature Tg of 170° C. The product is a SILTEM RESINSTM1500 model product purchased from Saudi Basic Industries Corporation.

[0062] The polyimide resin is a thermoplastic polyimide resin powder having a glass transition temperature Tg of 323° C. and an average particle size D50 of 20 μm. The product is purchased from Suzhou Yuxin Tiancai New Material Application Technology Co., Ltd. in China and is a model product of Toughimid-3252.

[0063] The heat stabilizer was cerium oxide powder, purchased from China Suzhou Zhengde Rare Earth Materials Co., Ltd., model ZD-9602.

[0064] The reinforcing fibers are glass fibers with an average diameter of 11 μm and an average length of 1 mm, purchased from China Jushi Company.

[0065] The filler is a composition of silicon dioxide and aluminum hydroxide with a mass ratio of 7:20.

[0066] The MQ resin is a vinyl MQ resin with a vinyl content of 2.7 wt %, purchased from Shandong Dayi Chemical Co., Ltd., China, and sold under the model DY-VMQ101.

[0067] The silicone oil is a composition of terminal vinylphenyl silicone oil and hydroxyl silicone oil in a mass ratio of 4:3; the phenyl content of the terminal vinylphenyl silicone oil is 29 mol%, and it is purchased from AndisilSF2450 model product sold by China Anbia Special Silicone (Nantong) Co., Ltd.; the hydroxyl content of the hydroxyl silicone oil is 8.5 wt%, and it is purchased from QJ203 model product sold by China Yangzhou Hongyuan New Materials Co., Ltd.

[0068] The self-healing agent is boric acid; the vulcanizing agent is diisopropylbenzene peroxide, which is purchased from Arkema, France, and is a LUPEROX_DC40P-SP2 product.

[0069] The preparation method of the sealing tape specifically comprises the following steps: S1: putting silicone resin, silicone modified resin, polyimide resin, heat stabilizer, reinforcing fiber and filler into a kneader for one kneading, stirring at a material temperature of 200°C for 3 hours, and after completion, after tableting and detecting that there are no particles, the material is cooled to below 80°C to obtain an intermediate; S2: putting MQ resin, silicone oil and self-healing agent into a high-speed mixer, stirring at 180°C and -0.09Mpa vacuum for 2 hours to obtain a tackifying composition; S3: mixing the intermediate and the tackifying composition The composition is sequentially put into a kneading machine for secondary kneading, stirred at a material temperature of 200°C for 1 hour, and naturally cooled to room temperature after completion to obtain a base material; S4: The base material is added between the double rollers of an open mixing mill with a cooling function, and a vulcanizing agent is added after thinning through 4 times, and the thinning through is continued for 4 times. The material temperature is controlled at 55°C throughout the whole process, and after uniform mixing, a sheet is produced to obtain a sealing rubber compound; S5: The sealing rubber compound is fed into an extruder, the material temperature is controlled at 80°C, extruded onto the unwinding isolation layer and formed into a sealing rubber layer through a roller press, and after completion, it is rolled up and cut to obtain a sealing tape of a desired size.

[0070] Example 2 The only difference between this embodiment and Embodiment 1 is that the sealant layer is composed of the following components, measured by mass: 58 parts of silicone resin, 2 parts of silicone modified resin, 8 parts of polyimide resin, 5 parts of heat stabilizer, 2 parts of reinforcing fiber, 13 parts of filler, 10 parts of MQ resin, 6 parts of silicone oil, 1 part of self-healing agent, and 3 parts of vulcanizing agent.

[0071] The mass ratio of the phenyl vinyl silicone rubber resin to the modified octamethylcyclotetrasiloxane resin is 50:8.

[0072] The heat stabilizer is a composition of cerium oxide powder and ferric oxide powder, with a mass ratio of 3:2.

[0073] The reinforcing fibers are aramid short fibers with an average diameter of 12 μm and an average length of 3 mm, which are purchased from Taipron para-aramid-short fiber products sold by China Taihe New Materials Co., Ltd.

[0074] The filler is a composition of silicon dioxide and aluminum hydroxide with a mass ratio of 3:10.

[0075] The silicone oil is a composition of terminal vinyl phenyl silicone oil and hydroxy silicone oil, with a mass ratio of 2:4.

[0076] Example 3 The only difference between this embodiment and Embodiment 1 is as follows: the sealant layer, calculated by mass, consists of the following ingredients: 76 parts of silicone resin, 2 parts of silicone modified resin, 4 parts of polyimide resin, 2 parts of heat stabilizer, 1 part of reinforcing fiber, 10 parts of filler, 5 parts of MQ resin, 6 parts of silicone oil, 1 part of self-healing agent, and 1 part of vulcanizing agent.

[0077] The mass ratio of phenyl vinyl silicone rubber resin to modified octamethylcyclotetrasiloxane resin is 70:6.

[0078] The reinforcing fibers are aramid short fibers with an average diameter of 12 μm and an average length of 3 mm, which are purchased from Taipron para-aramid-short fiber products sold by China Taihe New Materials Co., Ltd.

[0079] The filler is a composition of silicon dioxide and aluminum hydroxide with a mass ratio of 3:7.

[0080] The silicone oil is a composition of terminal vinyl phenyl silicone oil and hydroxy silicone oil, with a mass ratio of 4:2.

[0081] Example 4 The only difference between this embodiment and Embodiment 1 is that the sealant layer is composed of the following components, measured by mass: 66 parts of silicone resin, 4 parts of silicone modified resin, 4 parts of polyimide resin, 5 parts of heat stabilizer, 1 part of reinforcing fiber, 13 parts of filler, 10 parts of MQ resin, 6 parts of silicone oil, 1 part of self-healing agent, and 1 part of vulcanizing agent.

[0082] The mass ratio of phenyl vinyl silicone rubber resin to modified octamethylcyclotetrasiloxane resin is 55:11.

[0083] The phenyl vinyl silicone rubber resin has a number average molecular weight Mn of 600,000 Da, a phenyl content of 15 mol %, and a vinyl content of 0.25 mol %, and was purchased from Jiangxi Bluestar Silicone Company of China as a 785-50U product.

[0084] The heat stabilizer is ferric oxide powder.

[0085] The filler is a composition of silicon dioxide and aluminum hydroxide with a mass ratio of 3:10.

[0086] The silicone oil is a composition of terminal vinyl phenyl silicone oil and hydroxy silicone oil, with a mass ratio of 4:2.

[0087] Comparative Example 1 The only difference between this comparative example and Example 1 is as follows: the sealant layer, calculated by mass, consists of the following ingredients: 58 parts of silicone resin, 2 parts of silicone modified resin, 0 parts of polyimide resin, 5 parts of heat stabilizer, 3 parts of reinforcing fiber, 13 parts of filler, 10 parts of MQ resin, 7 parts of silicone oil, 3 parts of self-healing agent, and 2 parts of vulcanizing agent.

[0088] The organic silicone resin is a composition of phenyl vinyl silicone rubber resin and modified octamethylcyclotetrasiloxane resin, with a mass ratio of 56:2.

[0089] The filler is a composition of silicon dioxide and aluminum hydroxide with a mass ratio of 3:10.

[0090] Comparative Example 2 The only difference between this comparative example and Example 1 is as follows: the sealant layer, calculated by mass, consists of the following ingredients: 55 parts of silicone resin, 2 parts of silicone modified resin, 8 parts of polyimide resin, 1.5 parts of heat stabilizer, 3 parts of reinforcing fiber, 13 parts of filler, 10 parts of MQ resin, 7 parts of silicone oil, 1 part of self-healing agent, and 3 parts of vulcanizing agent.

[0091] The organic silicone resin is a composition of phenyl vinyl silicone rubber resin and modified octamethylcyclotetrasiloxane resin, with a mass ratio of 55:0.

[0092] The filler is a composition of silicon dioxide and aluminum hydroxide with a mass ratio of 3:10.

[0093] The heat stabilizer is ferric oxide powder.

[0094] Comparative Example 3 The only difference between this comparative example and Example 1 is as follows: the sealant layer, calculated by mass, consists of the following ingredients: 45 parts of silicone resin, 2 parts of silicone modified resin, 6 parts of polyimide resin, 5 parts of heat stabilizer, 3 parts of reinforcing fiber, 27 parts of filler, 10 parts of MQ resin, 7 parts of silicone oil, 0 parts of self-healing agent, and 2 parts of vulcanizing agent.

[0095] Comparative Example 4 The only difference between this comparative example and Example 1 is as follows: the sealant layer, calculated by mass, consists of the following ingredients: 60 parts of silicone resin, 2 parts of silicone modified resin, 8 parts of polyimide resin, 5 parts of heat stabilizer, 2 parts of reinforcing fiber, 13 parts of filler, 1.5 parts of MQ resin, 7 parts of silicone oil, 2 parts of self-healing agent, and 2 parts of vulcanizing agent.

[0096] The organic silicone resin is a composition of phenyl vinyl silicone rubber resin and modified octamethylcyclotetrasiloxane resin, with a mass ratio of 1:1.

[0097] The heat stabilizer is a composition of cerium oxide powder and ferric oxide powder, with a mass ratio of 3:2.

[0098] The reinforcing fibers are aramid short fibers with an average diameter of 12 μm and an average length of 3 mm, which are purchased from Taipron para-aramid-short fiber products sold by China Taihe New Materials Co., Ltd.

[0099] The filler is a composition of silicon dioxide and aluminum hydroxide with a mass ratio of 3:10.

[0100] Comparative Example 5 The only difference between this comparative example and Example 1 is that the phenyl vinyl silicone rubber resin is replaced by methyl vinyl silicone rubber with a number average molecular weight Mn of 640,000 Da, a phenyl content of 0 mol%, and a vinyl content of 0.24 mol%, purchased from the 110-3 model product sold by China Hesheng Silicone Company.

[0101] Comparative Example 6 The only difference between this comparative example and Example 1 is as follows: The preparation method of the modified octamethylcyclotetrasiloxane resin, by mass, specifically comprises the following steps: S1: 20 parts of octamethylcyclotetrasiloxane, 1.5 parts of phenyltrimethoxysilane, 0.5 parts of vinyltriethoxysilane, 0.6 parts of trifluoropropylmethylcyclotrisiloxane, and 0.2 parts of γ-glycidyloxypropyltrimethoxysilane are added to a reaction kettle in sequence, stirred at 60 rpm and 40 parts of deionized water are slowly added, then glacial acetic acid is added dropwise to adjust the pH of the system to 4.3, and the temperature is raised to 50°C for 3 hours. The mixture was stirred at 200 rpm for 2 hours to obtain a premix; S2: 0.08 parts of tetramethylammonium hydroxide were added to the premix, and the mixture was stirred at 160 rpm for uniform mixing. The mixture was then heated to 85°C, the vacuum pressure was controlled at -0.09 MPa, and the mixture was dehydrated for 1.5 hours. The mixture was then heated to 110°C and kept warm for 6 hours to obtain a preproduct; S3: The preproduct was kept at 150°C for 35 minutes under nitrogen protection, and then cooled to 120°C to remove low-boiling substances. The mixture was naturally cooled to room temperature after completion, and the product was taken out and washed through a 350-mesh sieve to obtain the product.

[0102] Comparative Example 7 The only difference between this comparative example and Example 1 is as follows: The preparation method of the modified octamethylcyclotetrasiloxane resin, by mass, specifically comprises the following steps: S1: 4.5 parts of octamethylcyclotetrasiloxane, 6.5 parts of phenyltrimethoxysilane, 2.4 parts of vinyltriethoxysilane, 3.2 parts of trifluoropropylmethylcyclotrisiloxane, and 1 part of γ-glycidyloxypropyltrimethoxysilane are sequentially added into a reaction kettle, stirred at 60 rpm and 55 parts of deionized water are slowly added, then glacial acetic acid is added dropwise to adjust the pH of the system to 4.3, and the temperature is raised to 50°C for 3 hours. The mixture was stirred at 200 rpm for 2 hours to obtain a premix; S2: 0.08 parts of tetramethylammonium hydroxide were added to the premix, and the mixture was stirred at 160 rpm for uniform mixing. The mixture was then heated to 85°C, the vacuum pressure was controlled at -0.09 MPa, and the mixture was dehydrated for 1.5 hours. The mixture was then heated to 110°C and kept warm for 6 hours to obtain a preproduct; S3: The preproduct was kept at 150°C for 35 minutes under nitrogen protection, and then cooled to 120°C to remove low-boiling substances. The mixture was naturally cooled to room temperature after completion, and the product was taken out and washed through a 350-mesh sieve to obtain the product.

[0103] Performance Evaluation Initial adhesion: refer to standard GB / T4852-2002, the results are averaged from 10 tests and recorded in Table 1.

[0104] 180° peel force: refer to standard GB / T 2792-2014, the results are averaged from 10 tests and recorded in Table 1.

[0105] High temperature sealing: refer to standard HB 5481-91, temperature and time conditions are: 427℃×4h, the results are recorded in Table 1.

[0106] Removability after high temperature: refer to standard HB 5481-91, temperature and time conditions are: 427℃×4h, the results are recorded in Table 1.

[0107] Heat resistance: refer to standard HB 5481-91, temperature and time conditions are: 427℃×4h, the results are recorded in Table 1.

[0108] Odor: Refer to standard GMW3205, the results are recorded in Table 2.

[0109] Tensile strength and elongation at break: refer to standard GB / T528-2009, the samples were pre-heat treated at 427℃×4h, and the average value of 10 tests was recorded in Table 2.

[0110] From the final performance test results of the embodiments and comparative examples, comparative examples 1 to 7 achieved worse performance results relative to the embodiments. From the comparison, in Example 2 compared with Comparative Example 1, the thermoplastic polyimide powder can greatly improve the adhesion to the PI film; in Example 2 compared with Comparative Example 4, the MQ resin has a greater effect on the initial adhesion; in Example 2 compared with Comparative Example 5, the selection of phenyl vinyl silicone rubber resin has a significant effect on heat resistance; in Example 1 compared with Comparative Example 3, the tackifying composition is beneficial to high-temperature sealing and reducing residues. Moreover, Comparative Example 1 does not use thermoplastic polyimide powder, and it cannot be peeled off as a whole in the high-temperature removable test, and a large amount of residue appears; in Comparative Example 3, boric acid is not used, and the high-temperature sealing has significant air leakage, and there is more residue when it is removed at high temperature; Comparative Examples 6 and 7 have poor overall performance because they did not produce the modified resin with the best performance.

Claims

1. A sealing tape, characterized in that: The structure includes an isolation layer and a sealant layer located on the surface of the isolation layer; The thickness of the isolation layer is 0.05-0.2 mm; The isolation layer is high temperature resistant release paper; The thickness of the sealant layer is 1.5-3.5 mm; The sealant layer is composed of the following components, by mass: 35-82 parts of silicone resin, 2-4 parts of silicone modified resin, 4-8 parts of polyimide resin, 2-5 parts of heat stabilizer, 1-3 parts of reinforcing fiber, 10-30 parts of filler, 5-10 parts of MQ resin, 4-10 parts of silicone oil, 1-3 parts of self-healing agent, and 1-3 parts of vulcanizing agent; The organic silicone resin is a composition of phenyl vinyl silicone rubber resin and modified octamethylcyclotetrasiloxane resin, with a mass ratio of (30-70): (5-12); The number average molecular weight Mn of the phenyl vinyl silicone rubber resin is 550,000 to 650,000 Da; The phenyl vinyl silicone rubber resin has a phenyl content of 14-20 mol%, and a vinyl content of 0.1-0.4 mol%; The organosilicon-modified resin is an organosilicon-modified polyimide resin, with a melt index MI of 8-14 g / 10 min (295° C. / 6.6 kgf) and a glass transition temperature Tg of 160-200° C.

2. The sealing tape according to claim 1, characterized in that: The preparation method of the modified octamethylcyclotetrasiloxane resin specifically comprises the following steps: S1: octamethylcyclotetrasiloxane, phenyltrimethoxysilane, vinyltriethoxysilane, trifluoropropylmethylcyclotrisiloxane, and γ-glycidyloxypropyltrimethoxysilane are sequentially added into a reaction kettle, stirred at a speed of 50-70 rpm and deionized water is slowly added, then glacial acetic acid is added dropwise to adjust the pH value of the system to 4-4.5, and the temperature is raised to 45-50° C. and stirred at a speed of 200-250 rpm for reaction for 2-3 hours to obtain a premix; S2: in the premix, Add tetramethylammonium hydroxide, stir evenly at a speed of 150-180 rpm, then heat to 80-85°C, control the vacuum pressure to -0.09-0.08 MPa, dehydrate for 1.5-2 hours, then heat to 110-115°C, keep warm for 6-7 hours to obtain a pre-product; S3: keep the pre-product at 145-150°C for 30-40 minutes, and protect with nitrogen, then cool to 120-125°C to remove low-boiling substances, and naturally cool to room temperature after completion, and take out the product and wash it through a 300-400 mesh sieve to obtain; The mass ratio of octamethylcyclotetrasiloxane, phenyltrimethoxysilane, vinyltriethoxysilane, trifluoropropylmethylcyclotrisiloxane and γ-glycidyloxypropyltrimethoxysilane is (10-11): (3-3.5): (1-1.2): (1.8-2): (0.6-0.8).

3. The sealing tape according to claim 2, characterized in that: The polyimide resin is thermoplastic polyimide resin powder.

4. The sealing tape according to claim 3, characterized in that: The glass transition temperature Tg of the thermoplastic polyimide resin powder is 300-350° C.; the D50 average particle size of the thermoplastic polyimide resin powder is 15-25 μm.

5. The sealing tape according to claim 4, characterized in that: The heat stabilizer is cerium oxide powder or ferric oxide powder or a combination thereof.

6. The sealing tape according to claim 5, characterized in that: The reinforcing fibers are glass fibers or aramid chopped fibers; the reinforcing fibers have an average diameter of 10 to 14 μm and an average length of 1 to 3 mm.

7. The sealing tape according to claim 6, characterized in that: The filler is a composition of silicon dioxide and aluminum hydroxide, with a mass ratio of (2-10): (5-20).

8. The sealing tape according to claim 7, characterized in that: The silicone oil is a composition of terminal vinyl phenyl silicone oil and hydroxy silicone oil, with a mass ratio of (2-4): (2-4).

9. A method for preparing a sealing tape according to any one of claims 1 to 8, characterized in that: The specific steps include: S1: Put the silicone resin, silicone modified resin, polyimide resin, heat stabilizer, reinforcing fiber and filler into a kneader for primary kneading, stir at a material temperature of 190-210°C for 2-4 hours, and after completion, press the tablet to detect that there are no particles and then cool the material to below 80°C to obtain an intermediate; S2: Put MQ resin, silicone oil and self-healing agent into a high-speed mixer, stir at 175-185°C and a vacuum degree of -0.10-0.09Mpa for 2-3 hours to obtain a tackifying composition; S3: Put the intermediate and the tackifying composition into the kneader in turn for secondary kneading, stir at a material temperature of 190-210°C for 0.5-1.5 hours, and naturally cool to room temperature after completion to obtain a base material; S4: Add the base material between the double rollers of an open mixing mill with a cooling function, add the vulcanizer after thinning through 3 to 5 times, continue to thin through 3 to 5 times, control the material temperature at 50 to 60°C during the whole process, and obtain the sealing rubber compound after mixing evenly; S5: Feed the sealing rubber compound into an extruder, control the material temperature at 70 to 80°C, extrude it onto the unwinding isolation layer and form a sealing rubber layer through a roller press, and after completion, rewind and cut it to obtain a sealing tape of a desired size.

10. Use of the sealing tape according to any one of claims 1 to 8 in a process for preparing high-performance composite materials for aviation.

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