High-temperature-resistant vacuum bag butyl rubber sealing tape as well as preparation method and application thereof

Abstract

The invention relates to the technical field of polymer composite materials, in particular to a high-temperature-resistant vacuum bag butyl rubber sealing tape, a preparation method and application. According to the invention, butyl / halogenated butyl is taken as a base adhesive, and is matched with PIB-liquid butyl-operating oil for plasticizing, active / heavy calcium carbonate and coupling modified nano-sheet filler, SP-1055 alkyl phenolic aldehyde and C5 hydrogenated resin (in a ratio of (0.6-1.4): 1), ZnO / MgO dual-activation (in a ratio of 0.15-0.50), and short fibers and TAIC / TMPTA (triallyl isocyanurate / trimethylolpropane triacrylate) can be selected. The material is prepared through banburying-low shear extrusion. The vacuum degree of the adhesive tape is reduced by less than or equal to 25% when the adhesive tape is cured at 240-260 DEG C, the adhesive tape is cleaned and stripped after being cured, the cold flow is low, and the highest use temperature reaches 260 DEG C.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, and in particular to a high-temperature resistant vacuum bag butyl rubber sealing tape, its preparation method, and its application. Background Technology

[0002] Vacuum bag forming / curing processes for composite materials (such as lightweight components for aerospace, wind power, shipbuilding, and automobiles) require the application of sealing tape between the mold flange and the vacuum bag film to form a closed system that can be vacuumed and remains airtight throughout the heating, heat preservation, and cooling processes. The sealing tape typically uses butyl elastomers as the base material, supplemented with plasticizers, fillers, and binders / vulcanizing agents, and is produced into strip or tape-shaped products through compounding and extrusion. Its core technical requirements include: maintaining a leak-proof seal for a long period under curing temperatures and resin exothermic peak conditions (often ≥180℃); preventing significant thermal flow / creep under high-temperature stress and pressure differentials; and achieving "clean peeling without visible residue" from the mold and bag film after curing.

[0003] Regarding commercially available process materials, the nominal temperature resistance of mainstream vacuum bag sealing tapes is mostly concentrated in the range of approximately 204–232°C. For example, in Aerovac's publicly disclosed product series, varieties such as SM5127 / SM5130 / SM5142 can be cured at a maximum of 400°F (≈204°C), while SM5143 / SM5144 can reach 424°F (≈218°C). A few high-temperature grades (such as SM5126 and VAC-SEAL2026) are claimed to withstand up to 450°F (≈232°C). There are also a few "ultra-high temperature grade" products (such as SM5160) that are claimed to withstand thermal cycling at 752°F (≈400°C), but the substrate of these products is different from that of this invention, and they are often used for specific thermoplastic / metal bonding or special process windows, and the suppliers have not disclosed their formulation and mechanism details. Overall, long-term sealing and cleaning demolding at ≥204°C remain one of the higher challenges posed by engineering projects for sealing tapes.

[0004] Based on publicly available patents and literature, butyl / halogenated butyl systems have long been used as the base adhesive for vacuum bag sealing tapes due to their excellent airtightness and heat resistance potential. Early solutions often used a combination of butyl rubber (IIR) and chloroprene rubber (CR), along with polyisobutylene (PIB) to provide pressure-sensitive adhesion, and phenolic resins as implicit high-temperature vulcanizing agents / bonding resins, with nano-calcium carbonate and talc as the main fillers. Taking Chinese invention patent application CN101921551A as an example, its disclosed "high-temperature resistant vacuum bag sealing tape" is composed of IIR / CR / PIB and nano-CaCO3, claiming a maximum temperature resistance of up to 220℃ and no residue after demolding; this solution emphasizes the sealing performance during vacuuming and the cleanliness of peeling off after high temperatures.

[0005] Subsequent improvements included introducing modified phenolic resin and chopped fibers into the formulation to enhance high-temperature shape stability and seal retention. Chinese invention patent CN102796462B discloses a formulation containing cashew phenol-modified phenolic resin, nano-calcium carbonate, and glass fiber, targeting wind turbine blade and aircraft component manufacturing scenarios. It emphasizes vacuum sealing to prevent air leakage and residue-free demolding, claiming a "maximum operating temperature of 425℃." Although this temperature claim is significantly higher than common industry ratings, its "phenolic resin + chopped fiber reinforcement + nanofiller" approach has become a representative technical path for improving high-temperature shape stability and adhesion retention.

[0006] Other patents use chlorobutyl (CIIR) as the sole or primary base adhesive, combined with PIB pressure-sensitive tackifier, metal oxide activation, and phenolic resin curing to achieve stable use in the range of room temperature to 220°C. For example, Chinese invention patent CN105001538B explicitly states that by using CIIR base adhesive, a phenolic resin / zinc oxide curing system, and PIB to provide pressure sensitivity, a long-term seal can be maintained at a pressure difference of nearly 1 atm from room temperature to 220°C, and emphasizes the characteristic of "easy peeling when cooled to about 66°C," which is basically consistent with the description of similar international products.

[0007] Based on existing public information, we can see that: (1) In terms of process, sealing tapes generally adopt a process chain of internal mixing - open mixing (or kneading) - extrusion molding; industrial instructions and manuals generally emphasize the introduction of heat-sensitive additives and fibers / resins at lower end temperatures to avoid early reactions and ensure fiber dispersion and orientation. (2) In terms of formulation, IIR or halogenated IIR is used as the base adhesive, combined with PIB / processing oil to build pressure-sensitive tack and workability; active / heavy calcium and other mineral fillers provide cost / rheological balance; phenolic (bromine-containing) resin and metal oxides jointly build a heat-resistant crosslinking network; short fibers and layered nanofillers are added when necessary to inhibit high-temperature creep and reduce permeation. (3) In terms of performance boundaries, the common rated temperature resistance of mature products in the industry is about ≤218–232℃; while for long-term vacuum maintenance and cleaning demolding at ≥240–260℃, public information is relatively scarce, mostly remaining at the level of individual patent claims or special product promotion.

[0008] Regarding the combined goals of "high-temperature sealing, clean demolding, low cold flow, and good operability," the shortcomings of existing technologies are mainly reflected in the following aspects: (a) High-temperature creep / flow remains a direct cause of leakage and "bag bursting"; under a curing window of ≥240℃ and 2–4h, the traditional "high PIB ratio - high mineral filler filling" system is prone to edge creep under the combined effects of heat-pressure-vacuum. (b) Adhesive strength and clean peeling are difficult to achieve simultaneously: while increasing the ratio of tackifying resin to PIB is beneficial for initial tack at room temperature, it increases the risk of residue and cold flow after high temperatures; conversely, excessively high crosslinking density may reduce the interfacial adhesion to the bag / mold. Industry TDS and patents both use "rapid clean peeling after curing" as a selling point, indicating that this contradiction has long existed. (c) Sensitive window of resin vulcanization system: The reactivity, bromine content and compatibility of different modified phenolic resins vary significantly, requiring optimization in conjunction with halogenated butyl content, metal oxide ratio, and plasticizing / tackifying system. While publicly available information provides directions, it lacks universal data detailed to the "industrially replicable window". (d) Although there are academic and patent reports on the influence mechanism of structured filler parameters and short fiber geometry / surface on high-temperature stability and vacuum retention, the optimal combination between nanosheet fillers with different aspect ratios, interlayer spacing / specific surface area and fiber length / surface treatment still needs to be verified under specific formulations and processes. Summary of the Invention

[0009] To address the aforementioned technical problems, the present invention aims to provide a high-temperature resistant vacuum bag butyl rubber sealing tape. This sealing tape uses butyl / halogenated butyl as the base rubber, combined with a specific ratio of alkylphenol aldehyde vulcanized resin and C5 hydrogenated resin, an MgO / ZnO activation ratio, nano-sheet inorganic fillers, and short fiber reinforcement to achieve crosslinking network stability and shape stability control at high temperatures. This allows the tape to maintain vacuum (decline rate ≤25%), suppress thermal creep, and achieve clean demolding during composite RTM / autoclave / oven curing, while also considering room temperature initial tack, low cold flow, and extrudability.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A high-temperature resistant vacuum bag butyl rubber sealing tape, the sealing tape being prepared based on a formulation of 100 parts by weight relative to a base rubber, said formulation comprising:

[0012] 1) Base rubber: Butyl rubber is selected;

[0013] 2) Plasticizing system: including 35-55 parts of polyisobutylene, 3-8 parts of liquid butyl rubber and 35-50 parts of rubber processing oil;

[0014] 3) Inorganic fillers: including 100-150 parts of activated calcium carbonate, 5.0-40 parts of heavy calcium carbonate, and 1.0-20 parts of nanosheet inorganic fillers;

[0015] 4) Resin system: including alkylphenol aldehyde vulcanized resin and C5 hydrogenated petroleum resin, with a mass ratio of 0.6 to 1.4:1, totaling 10 to 35 parts;

[0016] F) Activation system: including 1.0 to 10.0 parts of stearic acid, 5.0 to 18 parts of zinc oxide and 2.0 to 5.0 parts of magnesium oxide, and the mass ratio of MgO / ZnO is 0.10 to 0.50.

[0017] Preferably, the butyl rubber is selected from one or more of butyl rubber IIR, chlorinated butyl rubber and brominated butyl rubber; the base rubber is selected from brominated butyl rubber and butyl rubber IIR, and the mass ratio of brominated butyl rubber to unsubstituted butyl rubber is 7:3 to 9.5:0.5.

[0018] Preferably, the formulation further includes 15 to 22 parts of reinforcing fiber; preferably, the reinforcing fiber is selected from one or two types of glass short fiber and aramid short fiber; more preferably, the aramid short fiber has a length of 3 to 9 mm; the glass short fiber has a length of 2 to 6 mm; and more preferably, the surface of the glass short fiber and / or aramid short fiber is treated with epoxy or RFL impregnation.

[0019] Preferably, the formulation includes 0.25-1.0 parts of sulfur, 0.5-3.0 parts of accelerator, and 0-3.5 parts of antioxidant; preferably, the accelerator is selected from one or more of dibenzothiazole disulfide (DM), tetrabenzylthiuram disulfide (TBzTD), and N-cyclopentyl-2-benzoimide (CZ); more preferably, the accelerator is selected from 0.5-1.5 parts of dibenzothiazole disulfide (DM) and / or 0.5-1.5 parts of tetrabenzylthiuram disulfide (TBzTD), optionally containing 0.2-1.0 parts of N-cyclohexyl-2-benzothiazole sulfenamide (CZ).

[0020] Preferably, the formulation further includes 1.0 to 3.0 parts of triallyl isocyanurate (TAIC) and / or 0.5 to 2.0 parts of trimethylolpropane triacrylate (TMPTA), and 0.5 to 2.0 parts of an anti-sulfurization reversion agent; preferably, the formulation further includes triallyl isocyanurate (TAIC) and trimethylolpropane triacrylate in a mass ratio of 1 to 3:1, with a total amount of 0.5 to 3.5 parts.

[0021] Preferably, the nanosheet-like inorganic filler has a median particle size D50 ≤ 1.0 μm and an aspect ratio ≥ 30, and is surface-modified with silane or an equivalent coupling agent; preferably, the nanosheet-like inorganic filler is selected from one or two of organo-mica, layered silicates, or montmorillonite modified with quaternary ammonium salts; its specific surface area is ≥ 10 m². 2 / g, interlayer spacing ≥1.2nm.

[0022] Preferably, the alkylphenol aldehyde vulcanizing resin is SP-1055 sheet resin, with a mass ratio of 0.7 to 1.3:1 to C5 hydrogenated resin, and the bromine content of SP-1055 sheet resin is 6 to 9 wt%.

[0023] Preferably, the MgO / ZnO mass ratio is 0.20 to 0.40.

[0024] Furthermore, the present invention also provides a method for preparing the sealing tape, the method comprising the following steps:

[0025] S1: Mix the base rubber and inorganic filler at 110-130℃, then add polyisobutylene, liquid butyl and rubber processing oil and mix well.

[0026] S2: After cooling to ≤95℃, add reinforcing fiber, ZnO, MgO and accelerator in sequence, and mix evenly;

[0027] S3: Add alkylphenol aldehyde vulcanized resin and C5 hydrogenated resin at a temperature ≤95℃ and mix them evenly;

[0028] S4: Add the remaining other formulation ingredients at the end under low shear conditions of ≤90℃, then extrude the mixture into a 2.0~6.0mm thick tape and wind it up.

[0029] Furthermore, the present invention also provides a sealing method, which uses the sealing tape to seal the contact boundary between the composite material mold and the vacuum bag film. Under curing conditions of 240-260℃ and 2-4h, the vacuum degree reduction rate is ≤25% and there are no visible residues after demolding.

[0030] The design principle of the formulation of this invention is as follows:

[0031] 1. Base Rubber System – Functional Division of Halogenated / Unsubstituted Butyl Groups

[0032] Butyl rubber (IIR) possesses low unsaturation and excellent airtightness, but its heat resistance after sulfur vulcanization is limited. Brominated butyl rubber (BIIR) introduces active sites, enabling efficient reactions with alkylphenol aldehyde resins and metal oxides to construct a more heat-resistant crosslinking network. Using BIIR as the main component provides reactivity and heat-resistant crosslinking, while a small amount of IIR modifies processing and viscoelasticity, avoiding the risks of excessive hardening and embrittlement associated with pure BIIR. Under high temperature and long-term conditions, network rearrangement and reversion are suppressed, achieving a balance between airtightness and dimensional stability.

[0033] 2. Plasticizing / Tackifying System – Ternary “Soft-Tack-Stable” Balance

[0034] Polyisobutylene (PIB) provides room temperature initial tack and spreadability; liquid butyl improves cohesion and compatibility with the base adhesive; and the processing oil finely adjusts viscosity and extrusion flow. A gradient plasticizer is established using three components with different molecular weights and polarities to reduce high-temperature flow activity without sacrificing initial tack, while a physical support network inhibits thermal creep. Higher PIB levels increase initial tack but exacerbate cold and hot flow; higher processing oil levels dilute the network and reduce modulus, therefore an upper limit is set and synergistically constrained with fibrous / sheet fillers.

[0035] 3. Resin System – Synergistic Effect of Reactive Adhesion and Physical Tackification

[0036] Alkylphenol aldehyde resin SP-1055 undergoes resin vulcanization with (halogenated) butyl in the presence of ZnO / MgO, forming a heat-resistant crosslink and providing chemical adhesion. C5 resin provides physical tackification and surface wetting, reducing pressure sensitivity dependence during construction. Insufficient SP-1055 results in inadequate high-temperature adhesion retention and shape stability; excessive SP-1055 makes the system too hard and difficult to peel off; insufficient C5 leads to weak initial adhesion, while excessive C5 increases the risk of residue and cold flow. Therefore, a balance of "post-heat adhesion - clean peeling" is achieved at a ratio of 0.6 to 1.4:1.

[0037] 4. Activation / Acid Absorption System – ZnO / MgO Dual-Track Synergistic Effect

[0038] ZnO promotes effective crosslinking between halogenated butadiene and resin and improves interfacial bonding; MgO absorbs byproduct acid, inhibits reversion and early aging, and slows down the crosslinking rate, thus improving network stability. Too low an MgO ratio results in insufficient acid neutralization and easy network regression; too high an MgO ratio affects vulcanization kinetics and processing safety. Therefore, a reasonable window is set to balance crosslinking efficiency, reversion inhibition, and scorch safety.

[0039] 5. Inorganic fillers and sheet-like nanofillers: a triple optimization of cost, shape stability and barrier properties

[0040] The sheet-like high aspect ratio forms a "zigzag diffusion path," significantly reducing gas / volatile matter permeation and increasing high-temperature modulus; surface coupling enhances interfacial bonding with the matrix, avoiding interfacial debonding and residue caused by high filler content. It forms a multi-scale "plate-bridge" structure with short fibers, microscopically restricting molecular chain slippage and macroscopically inhibiting edge creep.

[0041] 6. Reinforcing Fibers – Short Fiber Backbone Inhibits High-Temperature Creep

[0042] Short fibers form an oriented skeleton in the extrusion / layout direction, bearing high-temperature shear and pressure differential, significantly reducing isothermal creep and flange side creep; surface treatment improves interfacial shear strength, avoiding "pull-out" failure. Aramid has high specific modulus and good heat resistance, while glass fiber is low-cost and rheology-friendly; they can be used together to achieve a balance between shape stability and processing.

[0043] 7. Vulcanization and Acceleration System – Primarily based on resin vulcanization, with controlled low sulfur content.

[0044] Low sulfur / controlled promotion inhibits small molecule migration and high-temperature residue; TBzTD reduces the risk of nitrosamines; it forms a dual support for chemical cross-linking in parallel with the SP-1055 network. Adding 0.5–2.0 parts of an anti-reversion agent (such as BMI-type) stabilizes the high-temperature cross-linked structure, further improving modulus retention after thermal cycling.

[0045] 8. Free radical co-agents can increase crosslinking density when needed.

[0046] This invention uses 1.0–3.0 parts of TAIC and / or 0.5–2.0 parts of TMPTA, with a mass ratio of 1–3:1 (total 0.5–3.5 parts). It is activated when a small amount of peroxide or irradiation is present in the process to improve the efficiency of free radical crosslinking and enhance high-temperature stability; however, excessive amounts may lead to shrinkage / embrittlement risks, therefore an upper limit is set and it is used in conjunction with resin vulcanization.

[0047] 9. Anti-aging and interface cleaning

[0048] Hindered phenolic antioxidants are used to inhibit thermo-oxidative chain breakage and surface fouling. Interface cleaning: By using low sulfur, controlled tackifying resin ratios, and low-temperature fiber / resin doping at the end, premature polymerization and migratable small molecules are reduced, ensuring clean peeling after curing.

[0049] In summary, this invention significantly improves the heat resistance and high-temperature stability of the crosslinked network without sacrificing room temperature initial tack and workability, inhibits thermal creep and edge creep, and reduces gas leakage channels at high temperatures through the barrier effect of layered fillers. At the same time, the matching of the resin system and metal oxides enhances the retention of post-heat adhesion and the cleanliness of peeling at the bag film / mold interface. Thus, under the curing conditions of 240-260℃ and 2-4h in composite RTM, autoclave or oven, the overall effect of vacuum degree reduction rate ≤25% and no visible residue after demolding is achieved. It also takes into account low cold flow during long-term storage, dimensional stability of extrusion molding and consistency of mass production. Detailed Implementation

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0051] I. Raw Materials and General Processes

[0052] 1. Selection of raw materials

[0053] Base rubber: Brominated butyl rubber (BIIR2828), butyl rubber (IIR532);

[0054] Plasticizing system: polyisobutylene (PIB, viscosity-average molecular weight of about 50,000-70,000), liquid butyl rubber, paraffin-based rubber processing oil;

[0055] Fillers: activated calcium carbonate (activated CaCO3), heavy calcium carbonate (heavy calcium carbonate), nanosheet inorganic fillers (organic mica or quaternary ammonium salt intercalated montmorillonite, D50≤1.0μm, thickness-to-diameter ratio≥30, treated with silane coupling);

[0056] Resin system: SP-1055 flake alkylphenol aldehyde vulcanized resin (Br6–9wt%), C5 hydrogenated petroleum resin;

[0057] Activators and additives: ZnO, MgO, stearic acid (SA), antioxidant 1010, sulfur (S), accelerators DM / TBzTD / CZ, co-agents TAIC / TMPTA, anti-reversion agents (BMI type).

[0058] 2. Preparation method (uniformly adopted, steps S1–S4):

[0059] S1: In a Banbury mixer at 110-130℃, first add base rubber → active / heavy calcium carbonate → PIB / liquid butyl / processing oil; mix for 6-8 minutes.

[0060] S2: Cool down to ≤95℃, then add short fiber, ZnO, MgO and accelerator in sequence, and mix well.

[0061] S3: Cool to ≤95℃, add SP-1055 and C5 resin, and mix thoroughly.

[0062] S4: Cool down to ≤90℃, add the remaining additives at the end, and extrude into a 3.0mm thick × 12mm wide tape using an extruder and then wind it up.

[0063] II. Test Methods and Criteria

[0064] 1. Vacuum holding (Vac): Aluminum alloy plate / flange simulates a sealing fixture, with a commonly used nylon-based vacuum bag film laid on it, and the pressure is evacuated to -0.095MPa; it is placed in a forced-air drying oven or autoclave and continuously run according to three programs: 240℃×2h, 250℃×3h, and 260℃×2h, and the rate of decrease in vacuum at the endpoints is recorded.

[0065] 2. Thermal creep / creep: Under the conditions of 250℃×3h and -0.09MPa, the lateral displacement of the sealing line or the creep distance at the edge is measured (mm).

[0066] 3. T-peel retention rate before and after heating (PeelR): The ratio (%) of the initial value at 23℃ to the value after 250℃×2h for T-peeling of nylon / co-extruded bag film.

[0067] 4. Cleaning and stripping residue level: 0-5 (0 = no visible residue, 5 = a lot of charred residue).

[0068] 5. Cold-flow: 23℃×7d, roll end / edge deformation (mm), or standard hanging displacement.

[0069] 6. Criteria for determining maximum operating temperature (MUT):

[0070] Using the same sealing clamp and bag film, perform a stepped procedure of 240℃×2h→250℃×3h→260℃×2h; MUT is defined as: the highest temperature at which the sample meets all criteria (Vac≤25%, Creep≤1.5mm, PeelR≥70%, Residue≤1, and no delamination) on a certain temperature plateau; if the sample does not meet the standard at 240℃, then perform a second verification at 230℃×2h; if it still does not meet the standard, then reduce the temperature to 225℃×2h and record the MUT.

[0071] Criteria (compliance standards): Vac≤25%; Creep≤1.5mm; PeelR≥70%; Residue≤1; Cold-flow≤2.0mm.

[0072] III. Examples (Ex1–Ex5, unit: phr)

[0073]

[0074]

[0075] Example Performance Results

[0076]

[0077] Conclusion: Ex1–Ex5 all meet the criteria (Vac≤25%; Residue≤1; etc.).

[0078] IV. Comparative Examples (CE1–CE10, unit: phr)

[0079]

[0080] Example Performance Results

[0081] index CE1 CE2 CE3 CE4 CE5 CE6 CE7 CE8 CE9 CE10 Vac (%) 34 36 33 28 31 29 39 41 30 27 Creep(mm) 2.4 2.6 2.2 1.9 2.1 2.0 3.8 4.1 2.0 1.8 PeelR (%) 60 55 58 88* 62 65 48 50 60 70 Residue(0–5) 2 2–3 2 3–4* 2 2 2–3 2–3 1–2 2–3 Cold-flow (mm) 2.0 2.1 1.9 2.3 2.1 2.0 5.2 4.9 1.6 1.8 MUT(°C) 230 230 230 240 230 230 225 225 230 230

[0082] *CE4: Although PeelR is higher at higher temperatures, MUT is limited to 240°C because Residue>1 (cleaning and peeling are not satisfied).

[0083] Breakthrough points summary: CE1 (MgO=0) → MgO / ZnO=0 (lacking dual activation); CE2 (ZnO=6) → below 10; CE3 / CE4 → SP-1055:C5 ratio <0.6 or >1.4; CE5 / CE6 → missing or unmet morphological parameters of sheet-like nanofillers; CE7 / CE8 / CE9 → plasticizing system exceeding the upper limit / below the lower limit; CE10 → resin system mismatch (no C5).

[0084] V. Interpretation of Results

[0085] 1. Necessity of dual activation of ZnO / MgO: Both CE1 (no MgO) and CE2 (insufficient ZnO) show Vac↑, Creep↑, PeelR↓ or Residue↑, indicating that MgO is indispensable for acid absorption / anti-reversion and ZnO is indispensable for effective cross-linking of resin vulcanization; an imbalance between the two will lead to unstable cross-linking network and insufficient adhesion retention.

[0086] 2. Synergistic window of resin system: CE3 (SP-1055 is too low) has insufficient chemical bonding and temperature resistance sealing degradation; CE4 (SP-1055 is too high) has high PeelR, but Residue increases significantly and peeling is difficult, proving that the ratio window of 0.6–1.4:1 is the key to achieving "post-thermal adhesion retention and clean peeling".

[0087] 3. Morphology threshold of sheet-like nanofillers: Both CE5 (no sheet-like filler) and CE6 (poor morphology) lead to the deterioration of Vac and Creep, indicating that sheet-like fillers with D50≤1.0μm, thickness-to-diameter ratio≥30 and coupling modification can provide both barrier and morphological stability; once the morphology / interface does not meet the standards, the technical effect will decline significantly.

[0088] 4. The "soft-tack-stable" balance of the plasticizing system: CE7 (PIB too high) and CE8 (oil too high) show significant cold flow and thermal creep, leading to Vac deterioration; CE9 (PIB too low) results in insufficient initial tack and micro-leakage at the seal line. Comparing Ex1–Ex5, it is evident that the gradient plasticizing window of PIB 35–55, liquid resin 3–8, and oil 35–50 is crucial for balancing "room temperature initial tack and high temperature stability." CE10 indicates that while cross-linking can be formed using only SP-1055 without C5, insufficient initial tack / wetting and increased residue demonstrate that the synergy between reactive resins and physically tackifying resins is key to achieving workability and clean peeling.

[0089] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A high-temperature resistant butyl rubber sealing tape for vacuum bags, characterized in that, The sealing tape is prepared based on a formulation of 100 parts by weight relative to the base adhesive, the formulation comprising: 1) Base rubber: Butyl rubber is selected; 2) Plasticizing system: including 35-55 parts of polyisobutylene, 3-8 parts of liquid butyl rubber and 35-50 parts of rubber processing oil; 3) Inorganic fillers: including 100-150 parts of activated calcium carbonate, 5.0-40 parts of heavy calcium carbonate, and 1.0-20 parts of nano-sheet inorganic fillers; 4) Resin system: including alkylphenol aldehyde vulcanized resin and C5 hydrogenated petroleum resin, with a mass ratio of 0.6 to 1.4:1, totaling 10 to 35 parts; F) Activation system: including 1.0 to 10.0 parts of stearic acid, 5.0 to 18 parts of zinc oxide and 2.0 to 5.0 parts of magnesium oxide, and the mass ratio of MgO / ZnO is 0.10 to 0.

50.

2. The sealing tape according to claim 1, characterized in that, The butyl rubber is selected from one or more of butyl rubber IIR, chlorinated butyl rubber and brominated butyl rubber; the base rubber is selected from brominated butyl rubber and butyl rubber IIR, and the mass ratio of brominated butyl rubber to unsubstituted butyl rubber is 7:3 to 9.5:0.

5.

3. The sealing tape according to claim 1, characterized in that, The formulation further includes 15 to 22 parts of reinforcing fiber; preferably, the reinforcing fiber is selected from one or two types of glass short fiber and aramid short fiber; more preferably, the aramid short fiber has a length of 3 to 9 mm; the glass short fiber has a length of 2 to 6 mm; and more preferably, the surface of the glass short fiber and / or aramid short fiber is treated with epoxy or RFL impregnation.

4. The sealing tape according to claim 1, characterized in that, The formulation includes 0.25-1.0 parts of sulfur, 0.5-3.0 parts of accelerator, and 0-3.5 parts of antioxidant; preferably, the accelerator is selected from one or more of dibenzothiazole disulfide (DM), tetrabenzylthiuram disulfide (TBzTD), and N-cyclopentyl-2-benzoimide (CZ); more preferably, the accelerator is selected from 0.5-1.5 parts of dibenzothiazole disulfide (DM) and / or 0.5-1.5 parts of tetrabenzylthiuram disulfide (TBzTD), optionally containing 0.2-1.0 parts of N-cyclohexyl-2-benzothiazole sulfenamide (CZ).

5. The sealing tape according to claim 1, characterized in that, The formulation further includes 1.0 to 3.0 parts of triallyl isocyanurate (TAIC) and / or 0.5 to 2.0 parts of trimethylolpropane triacrylate (TMPTA), and 0.5 to 2.0 parts of anti-sulfurization reversion agent; preferably, the formulation further includes triallyl isocyanurate (TAIC) and trimethylolpropane triacrylate in a mass ratio of 1 to 3:1, with a total amount of 0.5 to 3.5 parts.

6. The sealing tape according to claim 1, characterized in that... The nanosheet-like inorganic filler has a median particle size D50 ≤ 1.0 μm and an aspect ratio ≥ 30, and is surface-modified with silane or an equivalent coupling agent; preferably, the nanosheet-like inorganic filler is selected from one or two of organo-mica, layered silicates, or montmorillonite modified with quaternary ammonium salts; its specific surface area is ≥ 10 m². 2 / g, interlayer spacing ≥1.2 nm.

7. The sealing tape according to claim 1, characterized in that, The alkylphenol aldehyde vulcanizing resin is SP-1055 sheet resin, with a mass ratio of 0.7 to 1.3:1 to C5 hydrogenated resin, and the bromine content of SP-1055 sheet resin is 6 to 9 wt%.

8. The sealing tape according to claim 1, characterized in that, The MgO / ZnO mass ratio is 0.20 to 0.

40.

9. A method for preparing the sealing tape according to any one of claims 1 to 8, characterized in that, The method includes the following steps: S1: Mix the base rubber and inorganic filler at 110-130 ℃, then add polyisobutylene, liquid butyl and rubber processing oil and mix well; S2: After cooling to ≤95 ℃, add reinforcing fiber, ZnO, MgO and accelerator in sequence and mix well; S3: Add alkylphenol aldehyde vulcanized resin and C5 hydrogenated resin at a temperature of ≤95 ℃ and mix evenly; S4: Cool to ≤90 ℃, add reinforcing fibers and other remaining formulation materials at the end under low shear conditions, extrude into a 2.0~6.0 mm thick tape after thinning, and then roll it up.

10. A sealing method, characterized in that: The sealing tape described in any one of claims 1 to 8 is used to seal the contact boundary between the composite material mold and the vacuum bag film. Under curing conditions of 240 to 260 °C and 2 to 4 h, the vacuum degree decrease rate is ≤25% and there is no visible residue after demolding.

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