Low-odor moisture-proof foaming reinforcing film and preparation method thereof

Abstract

The invention discloses a low-odor moisture-proof foaming reinforcing film and a preparation method thereof, and belongs to the technical field of high-performance composite materials. The film takes epoxy resin modifier, rubber master batch, Janus core-shell structure tackifying resin, a foaming agent, a curing accelerator, an amine cross-linking agent and filler as main components, the epoxy resin modifier is prepared by the following steps: reacting fluorine-containing polyether polyol with isocyanate to form a prepolymer, and then reacting with an epoxy resin molecular chain to form a block graft copolymer; therefore, the damp-heat stability and the interface bonding strength of the material are remarkably improved. The Janus core-shell structure tackifying resin with the amphiphilic characteristic and the inorganic filler treated by the silane coupling agent are introduced, so that the material has excellent mechanical reinforcing effect and dimensional stability after foaming and curing, and meanwhile, pungent smell generated in the curing process of a traditional foaming film is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-performance composite materials, and in particular to a low-odor moisture-resistant foaming reinforcing adhesive sheet and a preparation method thereof. BACKGROUND

[0002] At present, foaming reinforcing adhesive sheets have been widely used in the fields of lightweight structural parts of automobiles, shock-absorbing and noise-reducing layers of automobile bodies, and reinforcement and connection of building structures. Such adhesive sheets usually take epoxy resin or rubber resin as a matrix, and form lightweight materials with microporous structures under heat treatment conditions by adding foaming agents, so as to reduce the mass while ensuring the structural strength, and have the functions of sound insulation, sealing, impact resistance, etc. However, the existing foaming reinforcing adhesive sheets still have a series of technical bottlenecks affecting the performance and environmental friendliness in long-term use. First, the traditional epoxy-rubber composite system will release a large amount of organic amine and benzene volatile substances during the heat curing process, which not only causes odor pollution in the vehicle and the construction environment, but also may cause discomfort and environmental safety hazards to the operators. Second, the ordinary epoxy system is extremely sensitive to humidity, and is prone to problems such as water absorption swelling, interfacial debonding and mechanical property reduction in a high-humidity environment, resulting in reduced bonding reliability. Third, due to the multiple influences of resin polarity, gas diffusion and crosslinking density on the foaming process, the existing materials are often difficult to obtain uniform and stable cell structures while maintaining excellent mechanical strength. Especially in the application of reinforcing the automobile body, uneven pore size distribution of the foaming layer or aging of the bonding interface will directly affect the torsional stiffness and crash safety of the automobile body.

[0003] In view of this, the present application is proposed. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a low-odor moisture-resistant foaming reinforcing adhesive sheet and a preparation method thereof. By introducing Janus core-shell structure tackifying resin with amphiphilic properties and inorganic fillers treated with silane coupling agents, the material has excellent mechanical reinforcing effect and dimensional stability after foaming and curing, and effectively reduces the irritating odor generated during the curing process of the traditional foaming adhesive sheet.

[0005] In order to achieve the purpose of the present application, the following technical solutions are adopted: The present application provides a low-odor moisture-resistant foaming reinforcing adhesive sheet, which comprises the following raw materials in mass fraction: Epoxy resin modifier 50-80 parts; Rubber masterbatch 80-120 parts; Janus core-shell structure tackifying resin 5-15 parts; Foaming agent 3-8 parts; Curing accelerator 0.5-2 parts; an amine crosslinking agent 5-15 parts; a filler 40-80 parts; The epoxy resin modifier is a block graft copolymer formed by reacting a fluorine-containing polyether polyol with isocyanate to obtain an isocyanate-terminated prepolymer, and then reacting with a secondary hydroxyl group in a molecular chain of an epoxy resin.

[0006] Further, the epoxy resin is bisphenol A type epoxy resin E-51 or epoxy resin E-128.

[0007] Further, the molecular weight of the fluorine-containing polyether polyol is 500-2000, and the isocyanate is isophorone diisocyanate.

[0008] Further, the rubber masterbatch is obtained by mixing butadiene rubber and styrene-butadiene rubber at a mass ratio of (1:1)-(2:1).

[0009] Further, the foaming agent is 4,4'-oxybisbenzenesulfonyl hydrazide.

[0010] Further, the Janus core-shell structure tackifying resin is composed of an oleophilic core and a hydrophobic shell, the core is a hydrogenated petroleum resin or a polyolefin oligomer, and the shell is a reactive silicone or a fluorine-containing oligomer.

[0011] Further, the filler is talc powder or wollastonite powder treated with a silane coupling agent.

[0012] Further, the curing accelerator is 2-phenylimidazole.

[0013] Further, the amine crosslinking agent is adipic acid dihydrazide.

[0014] The application also provides a preparation method of the low-odor moisture-resistant foaming reinforcing adhesive sheet. The epoxy resin modifier and the rubber masterbatch are prepared respectively; The rubber masterbatch, the epoxy resin modifier, the foaming agent, the curing accelerator, the amine crosslinking agent, the Janus core-shell structure tackifying resin and the filler are sequentially added and uniformly mixed to obtain a mixture; The obtained mixture is extruded or calendered into a 1.0-2.0 mm thick sheet, covered with glass cloth and cut to obtain the low-odor moisture-resistant foaming reinforcing adhesive sheet.

[0015] The application has the following technical effects: The present application improves the compatibility and moisture resistance of the material from the molecular level by reacting fluorine-containing polyether polyol with isophorone diisocyanate to generate a prepolymer with excellent flexibility and hydrophobic properties, and then copolymerizing with the molecular chain of epoxy resin to construct a block grafting system with both polar and non-polar structural units. At the same time, the Janus core-shell structure tackifying resin with a double parent interface is used to form a self-adapting interface transition layer between the polar epoxy matrix and the non-polar rubber phase, which not only significantly enhances the initial adhesion and the adhesion after curing of the adhesive sheet, but also reduces the release of small molecules during the curing process, achieving the synergistic effect of low odor and high adhesion. In addition, by selecting inorganic fillers modified by silane coupling agent and a specific proportion of rubber masterbatch system, the gas regulation and mechanical reinforcement integration design of the foaming process is realized, so that the obtained foaming layer has uniform pore size and high size stability. Compared with the traditional technology, the system structure of the present application is stable, and the material after curing can still maintain high bonding strength and size retention rate under high humidity and heat conditions, solving the problem of performance degradation of the previous foaming reinforcing adhesive sheet due to humidity or aging. DETAILED DESCRIPTION

[0016] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0017] In a first aspect, the present application provides a low-odor moisture-resistant foaming reinforcing adhesive sheet, which comprises the following raw materials in mass fraction: epoxy resin modifier 50-80 parts; rubber masterbatch 80-120 parts; Janus core-shell structure tackifying resin 5-15 parts; foaming agent 3-8 parts; curing accelerator 0.5-2 parts; amine crosslinking agent 5-15 parts; filler 40-80 parts; wherein the epoxy resin modifier is a block grafting copolymer obtained by reacting fluorine-containing polyether polyol with isocyanate to obtain isocyanate-terminated prepolymer, and then reacting with the secondary hydroxyl group of the molecular chain of epoxy resin.

[0018] The application realizes the synergistic control of the polarity, flexibility and hygrothermal stability of the epoxy system by introducing the isocyanate-terminated prepolymer formed by the reaction of fluorine-containing polyether polyol and isocyanate, and then reacting with the secondary hydroxyl of the molecular chain of the epoxy resin to form a block graft copolymer. At the same time, through the organic combination of rubber masterbatch, Janus core-shell structure tackifying resin, special foaming agent and inorganic filler treated by coupling, the foaming reinforced adhesive sheet forms a systematic optimization balance in low odor, high moisture resistance, high adhesion and uniform foaming. The technical scheme of the application overcomes the key defects of the traditional epoxy-rubber foaming system, especially in the long-term service environment such as vehicle body structure reinforcement, building sealing and electronic packaging, and shows outstanding stability and environmental protection.

[0019] Specifically, the core of the foaming reinforced adhesive sheet of the application is the structure control of the epoxy resin modifier. The traditional foaming adhesive sheet usually adopts physical blending of epoxy resin with rubber or tackifying resin. Although this method can improve the flexibility to a certain extent, due to poor polarity compatibility, the system is prone to phase separation during curing and foaming, which affects the uniformity of the cell structure and the interfacial adhesion. The block graft copolymer obtained by the reaction of fluorine-containing polyether polyol and isocyanate to form a prepolymer and then with the molecular chain of the epoxy resin realizes the balanced distribution of polar and non-polar groups at the molecular level, so that the system shows excellent compatibility and micro-level interface stability at the macro level. The molecular chain of fluorine-containing polyether polyol is rich in C-F bonds and C-O-C segments, which endow it with low surface energy, high hydrophobicity and strong flexibility; when it reacts with isocyanate, the isocyanate group (-NCO) and the hydroxyl group (-OH) undergo addition reaction to form urethane bond (-NH-CO-O-), and the generated prepolymer retains unreacted -NCO groups at the end, which will act as active sites for reaction with epoxy resin in the subsequent step. When the prepolymer containing -NCO end groups is blended with epoxy resin, the residual hydroxyl groups at the end of the epoxy molecule or between the molecules in the system can further undergo addition reaction with isocyanate groups to form new urethane bonds or urea groups, so that the fluorine-containing polyether segment is grafted onto the molecular chain of the epoxy resin by chemical bonds. This process not only realizes the block copolymerization of polar epoxy segments and non-polar fluorine-containing flexible segments at the molecular level, but also makes the molecular structure of the product highly uniform and the chemical bond connection firm due to the unidirectionality and high selectivity of the reaction path, avoiding the drawbacks of phase separation or delamination in traditional physical blending systems. The block graft structure shows that the compatibility of the system is significantly improved, the dispersion uniformity is enhanced, and the interface bonding is more stable, which provides a basis for the high mechanical properties and good foaming structure of the material.

[0020] Secondly, the composite system of butadiene rubber and styrene-butadiene rubber is used in the present application, so that the material has good flexibility and high thermal stability. After mixing according to a specific mass ratio, the rubber sheet still has a continuous and uniform cell structure and excellent resilience after foaming, which ensures the stable reinforcing effect of the material in the cavity of the vehicle body or the complex structure. In addition, the foaming agent selected in the present application is 4,4'-oxybisbenzenesulfonyl hydrazide. The gas generated by the decomposition of this compound is stable and clean, does not produce irritating odor, and the amount of gas released is moderate, which can match the crosslinking rate of the system, ensure the uniformity and fineness of the cells, and prevent the collapse. This has key significance in controlling low odor and foaming stability.

[0021] In the interface enhancement design, the Janus core-shell structure tackifying resin is used. The traditional tackifying resin is usually a single-phase organic system, and its molecular structure cannot simultaneously consider the interface of polar resin and non-polar rubber, which easily leads to interface peeling or stress concentration. The Janus core-shell structure tackifying resin material is designed with amphiphilic property, that is, the lipophilic core is supported, and the outer layer is covered with a hydrophobic or reactive shell, so that it can automatically orient at the interface of epoxy and rubber phase at the molecular level, thereby forming a flexible transition layer during curing. This unique molecular orientation effect not only significantly improves the interfacial adhesion of the system, but also slows down the micro-crack propagation caused by stress concentration, thereby improving the long-term fatigue life of the material. At the same time, the Janus core-shell structure tackifying resin hardly releases small molecular by-products at high temperature, so it effectively reduces the odor source while maintaining high bonding strength, further improving the realization path of low odor performance.

[0022] In the selection of fillers, talc powder or wollastonite powder treated with silane coupling agent can be chemically bonded with the hydroxyl or epoxy group in the epoxy resin, thereby forming a stable skeleton support structure after foaming, which significantly improves the uniformity of the cell size and the compressive strength. The surface modification of the silane coupling agent further enhances the compatibility between the filler and the organic matrix, avoiding the aggregation or shedding of the filler, so that the mechanical strength and moisture resistance of the foaming layer are significantly improved. In addition, the synergistic effect of the curing accelerator 2-phenylimidazole and the amine crosslinking agent adipic acid dihydrazide can accelerate the curing reaction of the epoxy group, and at the same time form a dense crosslinking network, which not only ensures the curing degree of the system, but also controls the amount of low molecular release during the curing process. This reaction control strategy is the key chemical basis for realizing low odor and high structural stability.

[0023] In some embodiments, the epoxy resin is bisphenol A type epoxy resin E-51 or epoxy resin E-128.

[0024] In some embodiments, the molecular weight of the fluorine-containing polyether polyol is 500-2000, and the isocyanate is isophorone diisocyanate.

[0025] In some embodiments, the rubber masterbatch is obtained by mixing cis-butadiene rubber and styrene-butadiene rubber at a mass ratio of (1:1) to (2:1).

[0026] The cis-butadiene rubber, as a rubber material with high polarity, contains cis-butyl groups in its molecular chain. The introduction of cis-butadiene rubber ensures the interface performance and adhesion of the film. Cis-butadiene rubber also has good moisture resistance, which can effectively resist the influence of humidity and prevent the film from swelling, interface peeling and other phenomena in long-term humid environment, thereby prolonging the service life of the film. On the other hand, styrene-butadiene rubber, as a non-polar rubber, has good toughness and elasticity, and relatively high thermal stability. Its role in the system is to improve the flexibility and impact resistance of the film, especially in the reinforcement effect after foaming, styrene-butadiene rubber can effectively enhance the structural toughness of the foaming layer, prevent the rupture or collapse of the pore structure during foaming.

[0027] By suitable proportioning of cis-butadiene rubber and styrene-butadiene rubber, the final rubber masterbatch can not only maintain good flexibility, but also improve the moisture and heat stability of the material, especially in high humidity environment, ensuring the strength and adhesion of the film. This flexible ratio makes the foaming reinforcing film widely applicable to bonding needs in different environments, including automobile manufacturing, building structure reinforcement and other industrial applications.

[0028] In some embodiments, the foaming agent is 4,4'-oxybisbenzenesulfonyl hydrazide.

[0029] In some embodiments, the Janus core-shell structure tackifying resin is composed of a lipophilic core and a hydrophobic shell, the core is a hydrogenated petroleum resin or a polyolefin oligomer, and the shell is a reactive silicone or a fluorine-containing oligomer.

[0030] The present application constructs a core-shell structure with amphiphilic properties at the molecular level, which forms an energy transition layer between the polar epoxy phase and the non-polar rubber phase, thereby significantly improving the interface bonding strength, structural stability and environmental adaptability of the system. The Janus core-shell structure tackifying resin is composed of a lipophilic core and a hydrophobic shell, wherein the core is selected from a hydrogenated petroleum resin or a polyolefin oligomer, and the shell is a reactive silicone or a fluorine-containing oligomer.

[0031] In the traditional foaming reinforced adhesive film system, the tackifying resin often adopts a single phase structure, the molecular polarity of which is biased to one side, which can lead to polarity mismatch at the interface, resulting in problems such as phase separation, interface debonding or stress concentration, ultimately affecting the overall mechanical properties and service life of the material. The Janus core-shell structure tackifying resin realizes the simultaneous compatibility of polar and non-polar phases with the molecular configuration of amphiphilic characteristics. The core is that the lipophilic core can have van der Waals interaction and chain entanglement with the rubber masterbatch at the molecular scale, thereby firmly embedding in the non-polar matrix; while the reactive silicone or fluorine-containing oligomer in the hydrophobic shell can have chemical reaction or dipole interaction with the polar groups in the molecular chain or modified material of the epoxy resin, forming a firm interface bonding. The molecular orientation characteristics of this core-shell structure enable the tackifying resin to spontaneously arrange at the interface between the epoxy and rubber phases during the curing process, and the "Janus" like molecular structure forms a natural interface transition layer, which not only avoids the energy discontinuity caused by polarity mutation, but also ensures the compatibility and structural stability of the overall system.

[0032] On the other hand, the design of the Janus core-shell structure tackifying resin also fundamentally solves the common odor problem in traditional epoxy systems. In the conventional tackifier system, polar solvents or low molecular additives often release amine, alcohol or ester volatiles during the curing process, resulting in a significant odor of the finished adhesive film. Therefore, the Janus core-shell structure provided by the present application adopts a high molecular weight reactive shell layer, and there are almost no low molecular volatile components in the system, and the reaction process is crosslinking and curing between high molecular chains rather than low molecular chemical reaction, thus greatly reducing the VOC release amount and achieving low odor performance control from the source. At the same time, the dense outer layer formed by the fluorine-containing or silicone shell layer after curing can further prevent the escape of residual small molecules, thereby maintaining excellent environmental performance during the post-curing stage.

[0033] In some embodiments, the filler is talc powder or wollastonite powder treated with a silane coupling agent.

[0034] In some embodiments, the curing accelerator is 2-phenylimidazole.

[0035] In some embodiments, the amine crosslinking agent is adipic acid dihydrazide.

[0036] In a second aspect, the present application also provides a preparation method of a low-odor and moisture-resistant foaming reinforced adhesive film, comprising the following steps: Preparation of an epoxy resin modifier and a rubber masterbatch, respectively; Sequentially adding the rubber masterbatch, the epoxy resin modifier, the foaming agent, the curing accelerator, the amine crosslinking agent, the Janus core-shell structure tackifying resin and the filler, and mixing uniformly to obtain a mixture; The obtained mixture was extruded or calendered into 1.0-2.0 mm thick sheet, covered with glass cloth and cut to obtain low odor moisture resistant type foaming reinforcing adhesive sheet.

[0037] The following is described in conjunction with specific examples: Example 1 The epoxy resin E-51 used in this example is bisphenol A type, with an epoxy value of 0.51, purchased from Bluestar New Chemical Materials Co., Ltd.; The catalyst is dibutyltin dilaurate, purchased from Momentive Performance Materials; The core of the Janus core-shell structure tackifying resin is hydrogenated petroleum resin, and the shell is reactive silicone. The core material is purchased from Gohsenic, and the shell material is purchased from Shin-Etsu Chemical; The amine crosslinking agent is adipic acid dihydrazide, purchased from Aldrich; The filler is talc powder, 1250 mesh; The silane coupling agent is γ-aminopropyl triethoxysilane; In this example, 100 g of low odor moisture resistant type foaming reinforcing adhesive sheet was prepared.

[0038] The amount of each substance is shown in Table 1.

[0039] Table 1: Amount of each substance Detailed preparation process: First step: preparation of epoxy resin modifier Pre-reaction: In a 1000 mL four-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet and a condenser reflux device, 65 g of fluorine-containing polyether polyol and 65 g of isophorone diisocyanate were added in turn; Temperature control reaction: nitrogen protection was applied, stirring was started, and the temperature was slowly raised to 75±2℃, and the reaction was maintained at this temperature for 2.5 hours; during the reaction, the content of -NCO groups in the system was monitored by di-n-butylamine titration method, when the deviation between the measured value and the theoretical value was less than 0.5%, the reaction was determined to be completed, and the FPU prepolymer, i.e. fluorine-containing polyurethane prepolymer, was obtained; Grafting reaction: In another reaction kettle, 65 g of epoxy resin E-51 was preheated to 60±5℃ to melt and reduce the viscosity, and the FPU (fluorine-containing polyurethane) prepolymer prepared in the first step was slowly added to the epoxy resin under stirring. After the addition was completed, 0.5 g of catalyst dibutyltin dilaurate was added; Temperature maintenance and end point determination: the temperature of the reaction system was maintained at 85±2℃, and the reaction was continued for 3.5 hours to obtain the epoxy resin modifier, which was discharged and sealed for storage; Second step: preparation of rubber masterbatch Mixing: The mixing was carried out in a Brabender internal mixer, with the mixing chamber temperature preheated to 80°C. First, 60 g of butadiene rubber and 40 g of styrene-butadiene rubber were added into the mixing chamber in sequence. Mixing: The mixing was carried out at 80°C for 20 minutes at a rotor speed of 50 rpm until the two rubbers were fully mixed and formed a uniform blend. Sheeting: The mixed rubber was transferred to an open mill and thin passed three times at a roll temperature of 70°C, with a sheet thickness of about 3 mm. After cooling, the rubber was cut into small pieces to obtain the rubber masterbatch. Step 3: Pretreatment of fillers Preparation of treatment solution: 1.8 g of silane coupling agent KH-550 was mixed with 18 g of anhydrous ethanol to prepare a 10% silane solution. Surface treatment: 60 g of talc powder was placed in a high-speed mixer, and the silane solution was uniformly sprayed on the surface of the talc powder under stirring using a spraying device. Drying: After spraying, the treated talc powder was dried in an oven at 100°C for 2 hours to completely remove the ethanol and complete the coupling reaction of the silane, obtaining silane-treated talc powder. Step 4: Mixing Feeding: A "U"-shaped high-efficiency mixer with a heating jacket and S-shaped paddle was used to add the raw materials in the following order: rubber masterbatch 100 g, epoxy resin modifier 65 g, adipic acid dihydrazide 10 g, 2-phenylimidazole 1.25 g, 4,4'-oxybisbenzenesulfonyl hydrazide (OBSH) 5.5 g, Janus core-shell structure tackifying resin 10 g, and silane-treated talc powder 60 g. Mixing process: The mixer was closed, the jacket temperature was set to 50±5°C, and the material was preliminarily mixed at 100 rpm for 5 minutes, then stirred at 300 rpm for 25 minutes until the material was uniformly mixed, forming a mixed rubber with consistent color and no visible dry powder particles. Step 5: Molding and cutting Calendering: The mixed rubber was transferred to a three-roll calender, and the temperatures of the upper, middle, and lower rolls were set to 90°C, 85°C, and 80°C, respectively, with a roll gap of 1.5 mm. The rubber was fed into the roll gap and calendered into a uniform sheet.

[0040] Laminating reinforcing substrate: After the sheet was drawn out of the calender, a 0.18 mm thick glass cloth was laminated on the upper and lower surfaces of the sheet, and a set of cooling rollers was used to press and bond the sheet and the glass cloth firmly. Cutting and packaging: The laminated continuous sheet was guided to the cutting machine and cut into the specified size. The finished sheet was packaged with polyethylene film and placed in a paper box for storage in a cool and dry place.

[0041] Experimental Example 1: Odor and moisture resistance comparison test 1. Experimental purpose: to verify the advantages of the film of the present application in low odor and moisture resistance compared with traditional reinforced film.

[0042] 2. Sample preparation Example 1 sample: prepared according to the method of Example 1 described above.

[0043] Comparative Example 1 sample: a common foaming reinforced film formula on the market, which uses ordinary epoxy resin and physically blended rubber as the matrix, and its preparation process also uses conventional physical mixing and hot pressing molding method.

[0044] 3. Experimental method 3.1 Odor test Cut the sample into 10 cm x 10 cm sheets, place them in a 1 L sealed glass jar, and place them in an 80°C oven for 2 hours; Immediately after taking out, 5 trained odor testers will evaluate the odor level; Among them, level 1: no odor; Level 2: very low odor, can feel a slight odor but no irritation near the sample; Level 3: low odor, can clearly smell some odor but still no irritation; Level 4: obvious odor, odor easy to identify and feel slight irritation; Level 5: strong odor, strong, pungent and obvious discomfort; Level 6: strong odor, very strong, pungent and severe discomfort; 3.2 Moisture resistance test Place the sample in an 85°C / 85%RH environment for 168 hours; Immediately after taking out, test its peel strength; Experimental Example 2: Foaming uniformity and high temperature stability test 1. Experimental purpose: to verify the foaming behavior, dimensional stability at high temperature and mechanical property retention rate of the film of the present application.

[0045] 2. Sample preparation: same as Experimental Example 1.

[0046] 3. Experimental method 3.1 Foaming uniformity Place the sample in a 150°C oven for 20 minutes, cut the sample after cooling to observe the cell structure, and calculate the foaming ratio (height after baking / height before baking); 3.2 High temperature dimensional change rate Measure the initial size of the sample after foaming, then place it at 150°C for 1 hour, and measure the size change rate after cooling; 3.3 Reinforcement ratio The sample was bonded with a steel plate, baked at 150℃ for 20min, cooled for 24h, and the reinforcement ratio of 3-point bending was tested. The final test results are shown in Table 2 below: Table 2 Test results According to the experimental results, it can be seen that the low-odor moisture-resistant foaming reinforcing adhesive sheet prepared in Example 1 of the present application is significantly superior to Comparative Example 1 in terms of odor, moisture resistance and high temperature stability. The comprehensive advantages of the low-odor moisture-resistant foaming reinforcing adhesive sheet in environmental protection performance, moisture and heat reliability and thermal stability are verified, and the core lies in the synergistic effect of the Janus core-shell structure tackifying resin and the EP-FPU block copolymer, which successfully realizes the unity of low odor, strong interfacial bonding and long-term moisture resistance, which provides a high-performance and environmentally friendly structural reinforcement solution for the fields of automobiles, buildings and electronic packaging.

[0047] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present application.

Claims

1. A low-odor moisture-resistant foamed patching tape, characterized by, The foaming reinforcing adhesive sheet comprises the following raw materials in mass fraction: epoxy resin modifier 50-80 parts; rubber masterbatch 80-120 parts; Janus core-shell structure tackifying resin 5-15 parts; foaming agent 3-8 parts; curing accelerator 0.5-2 parts; amine crosslinking agent 5-15 parts; filler 40-80 parts; The epoxy resin modifier is a block graft copolymer obtained by reacting fluorine-containing polyether polyol with isocyanate to obtain isocyanate-terminated prepolymer, and then reacting with the secondary hydroxyl group of the molecular chain of epoxy resin.

2. The foamed reinforcing sheet according to claim 1, wherein The epoxy resin is bisphenol A type epoxy resin E-51 or epoxy resin E-128.

3. The foamed reinforcing sheet according to claim 1, wherein The molecular weight of the fluorine-containing polyether polyol is 500-2000, and the isocyanate is isophorone diisocyanate.

4. The foamed reinforcing sheet according to claim 1, wherein The rubber masterbatch is obtained by mixing butadiene rubber and styrene-butadiene rubber at a mass ratio of (1:1)-(2:1).

5. The foamed reinforcing sheet according to claim 1, wherein The foaming agent is 4,4'-oxybisbenzenesulfonyl hydrazide.

6. The foamed reinforcing sheet according to claim 1, wherein The Janus core-shell structure tackifying resin is composed of a lipophilic core and a hydrophobic shell, the lipophilic core is hydrogenated petroleum resin or polyolefin oligomer, and the hydrophobic shell is reactive silicone or fluorine-containing oligomer.

7. The foamed reinforcing sheet according to claim 1, wherein The filler is talc powder or wollastonite powder treated with silane coupling agent.

8. The foamed reinforcing sheet according to claim 1, wherein The curing accelerator is 2-phenylimidazole.

9. The foamed reinforcing sheet according to claim 1, wherein The amine crosslinking agent is adipic acid dihydrazide.

10. A process for preparing the low-odor moisture-resistant foamed patch of any one of claims 1 to 9, characterized in that, The method comprises the following steps: Preparation of epoxy resin modifier and rubber masterbatch respectively; rubber masterbatch, epoxy resin modifier, foaming agent, curing accelerator, amine crosslinking agent, Janus core-shell structure tackifying resin and filler are added in sequence, and mixed uniformly to obtain a mixture; The obtained mixture is extruded or calendered into a 1.0-2.0 mm thick sheet, covered with glass cloth and cut to obtain a low odor wet type foaming reinforcing adhesive sheet.

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