High-performance foaming pouring sealant and preparation method and application thereof

Abstract

The application discloses high-performance foaming potting glue and a preparation method and application thereof. The potting glue comprises A component and B component according to weight parts. The A component comprises the following components according to weight parts: 2-3 parts of self-catalyzing polyol, 25-30 parts of polyether polyol containing rigid benzene ring structure, 25-30 parts of high-polyester polyol, 8-10 parts of low-viscosity polyether polyol, 18-23 parts of phosphorus-containing liquid flame retardant, 6-8 parts of high-polyether polyol, 1.5-2.5 parts of foam stabilizer, 0.15-0.2 parts of chemical foaming agent and 0.4-0.5 parts of inhibitor. The B component is a mixture of diphenyl methane diisocyanate and polymethyl polyphenyl polyisocyanate. The potting glue does not need to add fillers, improves process fluidity and light weight, and has super strong adhesion to nickel steel and epoxy base materials.

Description

Technical Field

[0001] This invention relates to the field of polyurethane materials technology, and in particular to a high-performance foaming potting compound, its preparation method, and its application. Background Technology

[0002] As electronic and electrical equipment develops towards miniaturization, high power density, and high integration, problems such as heat accumulation, electromagnetic interference, and mechanical vibration generated by internal components are becoming increasingly prominent. Potting compounds, as key encapsulation and protection materials, are widely used in critical components such as power modules, new energy vehicle electronic control units, energy storage battery systems, and communication base station modules, playing a role in insulation, moisture protection, shock resistance, corrosion protection, and flame retardant protection.

[0003] In many application scenarios, especially in fields with extremely high requirements for safety and reliability such as aerospace, new energy vehicle battery packs, and high-end servers, extremely stringent requirements are put forward for the comprehensive performance of potting compounds: (1) High safety and flame retardancy: Short circuits or overloads inside equipment may cause fires, requiring potting compounds to meet the highest flame retardancy standard of UL94 V-0 to effectively block heat spread and buy critical time for personnel evacuation and equipment protection; (2) Excellent processability and permeability: Modern electronic modules have complex structures and dense component arrangements, requiring potting compounds to have excellent flowability (low viscosity) so that they can completely penetrate into narrow gaps and dense pins without applying excessive pressure, achieving perfect encapsulation without bubbles or voids, and avoiding the formation of local protection weaknesses; (3) Lightweight requirements: In mobile devices such as electric vehicles and drones, every gram of weight reduction is of great significance to improving the driving range. Therefore, under the premise of ensuring performance, reducing the density of potting materials has become a clear technological development trend; (4) Reliable structural adhesion: potting compound not only needs to encapsulate components, but also needs to serve as a structural bonding material to firmly bond components of different materials (such as nickel steel shells, brackets and epoxy resin-based circuit boards) into a whole to resist the stress caused by long-term vibration and thermal shock, and prevent delamination and cracking that lead to protection failure. Achieving ultra-high adhesion to both nickel steel (metal) and epoxy resin (polymer material), two substrates with huge differences in polarity and surface energy, is a major challenge.

[0004] Currently, the following are common potting compounds on the market:

[0005] Epoxy resin potting compounds: Although they have excellent bonding strength, hardness and chemical resistance, their viscosity is usually high and their penetration into complex structures is insufficient; after curing, they have high internal stress and are prone to cracking during thermal cycling; and in order to achieve high flame retardancy (V0), a large amount of halogenated flame retardants or inorganic fillers (such as aluminum hydroxide and magnesium hydroxide) are usually required, which will lead to a sharp increase in system viscosity, poor flowability, and a significant increase in density, and may affect the bonding performance and mechanical toughness of the cured product.

[0006] Silicone potting compounds offer excellent resistance to high and low temperatures, low stress, and good flowability. However, their adhesion to metals and epoxy materials is typically weak, often requiring a primer or surface treatment of the substrate, increasing process complexity and unreliability. While adhesion can be improved by adding functional fillers, this sacrifices their flowability and low density advantages. Their intrinsic flame retardancy is also generally poor, and achieving a V0 rating also depends on the addition of fillers.

[0007] Polyurethane potting compounds offer good flexibility and strong adhesion, but their temperature and hydrolysis resistance are relatively poor, and their stability in high-temperature and high-humidity environments faces challenges. Their high flame retardancy also faces the problem of performance imbalance caused by the addition of large amounts of flame-retardant fillers.

[0008] Foamed potting materials: In the existing technology, the foaming technology (chemical foaming or physical foaming) introduced to reduce density often leads to a significant decrease in the mechanical strength of the material (including the bonding strength). The unevenness of the cell structure may also impair the stability of flame retardant performance, forming a dilemma of "low density leads to low performance".

[0009] In summary, existing technologies exhibit a common "performance contradiction": achieving high flame retardancy (V0) often relies on high filler content, which directly conflicts with the goals of high flowability and low density (lightweight); while pursuing low density and good flowability often comes at the cost of sacrificing strong adhesion to metallic / non-metallic substrates. Currently, there is a lack of a comprehensive potting compound solution that can perfectly balance a series of key properties such as "high flame retardancy (V0), high flowability, no filler (or extremely low filler), low density, and ultra-high adhesion (especially for nickel steel / epoxy-based materials)".

[0010] Therefore, developing a new type of foaming potting compound that can overcome the above-mentioned technical bottlenecks and achieve multiple high-performance synergies is of urgent practical significance and huge market value for improving the safety, reliability and lightweight level of high-end electronic and electrical equipment. Summary of the Invention

[0011] Purpose of the Invention: The first purpose of this invention is to provide a high-performance foamed potting compound that does not require the addition of fillers, improves process flowability, lightweight, and meets the highest flame retardant safety standard (UL94 V0, 3mm thickness), while exhibiting superior adhesion to nickel steel and epoxy materials; the second purpose of this invention is to provide a method for preparing the high-performance foamed potting compound; the third purpose of this invention is to provide applications of the high-performance potting compound.

[0012] The high-performance foaming potting compound of the present invention comprises, by weight, component A and component B; component A comprises, by weight, 2-3 parts of self-catalytic polyol, 25-30 parts of polyether polyol containing a rigid benzene ring structure, 25-30 parts of high-functionality polyester polyol, 8-10 parts of low-viscosity polyether polyol, 18-23 parts of phosphorus-containing liquid flame retardant, 6-8 parts of high-functionality polyether polyol, 1.5-2.5 parts of foam stabilizer, 0.15-0.2 parts of chemical foaming agent, and 0.4-0.5 parts of inhibitor; component B is a mixture of diphenylmethane diisocyanate and polymethylene polyphenyl polyisocyanate.

[0013] The molar ratio (commonly referred to as the R value) of the hydroxyl groups (-OH) in component A and the isocyanate groups (-NCO) in component B needs to be greater than 1 to ensure a slight excess of component B. This allows for the use of a small amount of free -NCO to increase the degree of crosslinking and improve the strength of the product, without causing excessive heat release due to an excessive amount of component B, which could affect the lifespan of electronic components. Therefore, the preferred weight ratio of component A to component B is 1:0.75-0.80.

[0014] In polyether synthesis, the initiator is a compound with active hydrogen (such as polyols, amines, phenolic resins, etc.), on which propylene oxide / ethylene oxide polymerizes to form polyether polyols. The chemical structure of the initiator directly determines the functionality, molecular structure, and reactivity of the final polyether polyol. Toluene diamine and phenolic resin initiators have a unique advantage due to their high functionality and rigid benzene ring structure. Polyether polyols synthesized using these initiators have these rigid, polar benzene rings introduced into their molecular backbone. The benzene ring structure can generate stronger van der Waals forces, dipole-dipole interactions, and even π-π stacking with the surface of foam substrates (especially metals, wood, plastics, etc.), significantly improving physical adsorption. Simultaneously, the high functionality of the initiator results in a higher functionality of the synthesized polyether polyol, enabling the formation of a denser and stronger three-dimensional network structure during foam curing, thereby enhancing the cohesive strength of the foam and its anchoring ability to the adhered material.

[0015] Preferably, the polyether polyol containing the rigid benzene ring structure has a hydroxyl value of 330-400 mg KOH / g and a functionality greater than or equal to 3.5. More preferably, the polyether polyol containing the rigid benzene ring structure is CHR-6L33 or TD-405.

[0016] Preferably, the viscosity of the low-viscosity polyether polyol is below 200 mPa·s at 25°C. This polyether can reduce the viscosity of the formulation system, improve fluidity, and achieve better wetting of the bonded surfaces, thereby improving the adhesive performance. More preferably, the low-viscosity polyether polyol is CHE-210 (Changhua Chemical), NJ-310 (Jurong Ningwu New Material Co., Ltd.), or CHE-204 (Changhua Chemical). More preferably, the hydroxyl value of the low-viscosity polyether polyol is 107~295 mg KOH / g, and the functionality is 2~3.

[0017] Preferably, the high-functional polyester polyol has a hydroxyl value of 250-270 mg KOH / g and a functionality of 3.

[0018] More preferably, the high-functionality polyester polyol is HF-8730, which contains a cyclade structure as shown below:

[0019] .

[0020] The functionality of ordinary polyester polyols is generally 2, while HF-8730 used here is a polyester containing a cyclade structure with a functionality of 3. It has a high degree of crosslinking and better strength. Furthermore, the chemical bonds of aromatic polyesters are more stable and harder to break than those of aliphatic polyesters, resulting in better flame retardancy. At the same time, due to its higher initial decomposition temperature, it has better temperature resistance.

[0021] In polyurethane reactions, external catalysts (such as organotin compounds or tertiary amines) are typically required to accelerate the reaction between isocyanates (-NCO) and the hydroxyl groups (-OH) of polyols. Autocatalytic polyols, however, are polyols whose molecules themselves contain catalytically active groups (primarily tertiary amine groups), enabling them to significantly promote the reaction between -NCO and -OH without the need for an external catalyst. Autocatalytic polyols are formed by introducing amines into polyether or polyester chains, creating polyols with tertiary amine groups. These polyols eliminate the need for additional catalysts, reducing formulation complexity and avoiding the use of harmful catalysts such as organotin compounds, making them more environmentally friendly and healthier. More importantly, they provide a more stable reaction profile, reducing side reactions and avoiding the negative impact of catalyst residues on aging resistance and hydrolysis resistance.

[0022] Preferably, the hydroxyl value of the autocatalytic polyol is 260-805 mg KOH / g, and the functionality is greater than or equal to 3.

[0023] Preferably, the autocatalytic polyol is CN-8119 (Changneng Energy Saving New Materials Technology Co., Ltd.) or NJ-403 (Jurong Ningwu New Materials Co., Ltd.).

[0024] Preferably, the high-functionality polyether polyol has a hydroxyl value of 365-520 mg KOH / g and a functionality of 5-6. It is selected from one or more of NJ-8238 (Jurong Ningwu New Materials Co., Ltd.) and NJ-6249 (Jurong Ningwu New Materials Co., Ltd.).

[0025] Preferably, the halogen-free phosphorus-containing liquid flame retardant is a phosphonate or phosphate ester additive flame retardant, selected from one or more of dimethyl propylphosphonate (DMPP) and triethyl phosphate (TEP).

[0026] Preferably, the chemical foaming agent is deionized water.

[0027] Preferably, the foam stabilizer is an organosilicon surfactant selected from at least one of L-6900 (Momentive Advanced Materials Group), M-8860 (Mestide Chemicals) and M-88115 (Mestide Chemicals).

[0028] Preferably, the inhibitor is an acidic compound selected from at least one of formic acid and lactic acid.

[0029] Preferably, component A further includes a color paste. More preferably, the color paste is a blue color paste.

[0030] Preferably, the diphenylmethane diisocyanate accounts for 10-15 wt% of the total weight of the mixture. More preferably, the functionality of the mixture is greater than 2.7. Pure MDI has low viscosity, which is helpful for improving flowability, but its functionality is low. PAPI, on the other hand, has a rigid benzene ring structure and high functionality, resulting in high crosslinking density and high product strength. By blending the two in a suitable ratio, both excellent flowability and high strength can be achieved. Preferably, the diphenylmethane diisocyanate is selected from at least one of MDI-50 (Wanhua Chemical Group Co., Ltd.) and Lupranate MI (BASF (China) Co., Ltd.); PAPI is selected from at least one of PM-400 (Wanhua Chemical Group Co., Ltd.) and Lupranate M70L (BASF (China) Co., Ltd.).

[0031] The preparation method of the high-performance foaming potting compound of the present invention includes the following steps:

[0032] (1) The raw material of component A is placed in the material cylinder of a dynamic mixer and mixed evenly, and then subjected to vacuum degassing treatment;

[0033] (2) The finished component A is mixed with component B through a dispensing machine and injected into the designated cavity, and then self-leveled and foamed. After curing, a high-performance potting compound is obtained.

[0034] Preferably, in step (1), the dispersion during the mixing process is 400-500 rpm, the stirring time is 45±2 min, the vacuum valve needs to be opened slowly to start vacuuming, the vacuum reaches 0.090 Mpa, the stirring time is 10±2 minutes, and it is filtered through a 50~100 mesh stainless steel filter and sealed in packaging.

[0035] The application of the high-performance foamed potting compound described in this invention in battery packs.

[0036] Preferably, the high-performance foaming potting compound is applied to the battery pack by on-site potting and molding within the battery pack using a dispensing machine. The specific preparation process is as follows:

[0037] (1) Substrate pretreatment: The battery pack casing (nickel steel) and internal modules (epoxy-based materials) must be kept clean and dry. Plasma treatment or flame treatment can be performed. The treatment parameters are as follows:

[0038] ① Plasma treatment: power 800-1200W, processing speed 2-5 m / min;

[0039] ②Flame treatment: distance 10-15 cm, treatment speed 3-6 m / min;

[0040] If surface treatment is not possible, this system can be directly potted without treatment, and the bonding strength can still meet the requirements. However, the internal cavity of the battery pack to be potted needs to be vacuum dried to remove moisture and dust from the cavity to prevent the polyurethane adhesive from generating bubbles or adverse reactions during the curing process.

[0041] (2) Injection and potting process:

[0042] This invention uses a low-pressure foaming dispensing machine for online mixing and potting. The specific process parameters are as follows:

[0043] ①See Table 1 for equipment selection and parameter settings.

[0044] Table 1 Equipment Selection and Parameters

[0045]

[0046] ② Equipment debugging:

[0047] Before starting the machine, check the material levels of components A and B to ensure sufficient material supply;

[0048] Preheat the material tank to the set temperature and circulate the heating for 30 minutes;

[0049] Calibrate the metering pump to ensure that the mixing ratio error is ≤ ±2%;

[0050] Dry run the pump to remove bubbles until the mixing head outputs a continuous, uniform, and bubble-free product.

[0051] ③ Filling and sealing operation:

[0052] Place the battery pack in the potting station and fix its position.

[0053] Height of the dispensing gun tip from the potting area: 20-50 mm;

[0054] Injection path: Use an "S" shaped or spiral path to ensure uniform filling;

[0055] Single injection volume: Calculated based on module volume, with 5-10% expansion space reserved;

[0056] Injection speed: Start fast and then slow down. Use high-speed injection (200-300 g / s) for the first 80% of the volume, and low-speed injection (50-100 g / s) for the remaining 20% ​​of the volume to prevent glue overflow.

[0057] Injection time: The injection time for a single module should be controlled between 15 and 60 seconds.

[0058] ④ Curing and molding:

[0059] Gel time control: 3-8 minutes (at 25℃)

[0060] Demolding time: 15-30 minutes (before proceeding to the next step).

[0061] Complete curing: Cure at 25℃ for 24 hours, or at 50℃ for 4-6 hours.

[0062] Environmental requirements during curing: temperature 20-30℃, relative humidity ≤70%.

[0063] Invention Mechanism: The key to the success of this invention lies in the creative design of a synergistic system based on multi-component polyurethane chemistry. This system, through precise molecular structure design and synergistic compounding of isocyanates, achieves a unified balance of high flowability, high strength, high adhesion, and controllable foaming from the source. Its core mechanism is as follows:

[0064] (1) Achieving both "high fluidity" and "high strength / high rigidity": The system uses low-viscosity polyether polyol as the main mobile phase and combines it with low-viscosity pure MDI as the reaction component. This ensures that the entire mixed system has extremely low initial viscosity from the raw material level, laying the foundation for high fluidity.

[0065] (2) Introducing polyether polyols with rigid benzene ring structures as "liquid reinforcing fillers": Before curing, their molecular structure helps maintain low viscosity; during the curing reaction, their benzene ring structures, as rigid segments, are in situ and uniformly embedded into the final polyurethane crosslinked network, greatly improving the modulus, strength, and thermal stability of the foam skeleton. This "flow first, then reinforce" strategy avoids the problem of a sharp increase in viscosity caused by the addition of solid fillers.

[0066] (3) Achieving both "low density (foaming)" and "ultra-high adhesion / high strength": High-strength hard-segment micro-regions formed by the reaction of rigid benzene ring polyols with MDI constitute the pillars and walls of the foam. Even if the material forms a low-density structure through water foaming, the mechanical strength of its cell walls is much higher than that of ordinary soft foam. This robust microstructure ensures that the overall material still has sufficient load-bearing capacity after foaming, providing a foundation for withstanding interfacial stress.

[0067] (4) The key to high-functionality crosslinking and interfacial wetting lies in the introduction of high-functionality crude MDI: its polyisocyanate structure significantly increases the crosslinking density of the system, forming a dense and strong three-dimensional network. This not only further strengthens the strength of the foam itself, but more importantly, the highly reactive isocyanate groups (-NCO) can form strong chemical bonds with the hydroxyl groups on the nickel steel surface and the active hydrogen (such as hydroxyl and amine groups) on the epoxy material surface in the early stage of curing (forming urethane, urea bonds, etc.). At the same time, the low viscosity of the system ensures its full wetting of the substrate surface, allowing the chemical reaction to occur at the interface to the maximum extent, thereby achieving ultra-high adhesion.

[0068] (5) Achieving a high flame retardant V0 synergistic effect: The rigid benzene ring structure itself has a good tendency to form char. During combustion, the benzene ring structure helps to form a stable char layer skeleton. When combined with flame retardant polyols (or reactive flame retardants) containing phosphorus, nitrogen or silicon elements, it can produce excellent synergistic flame retardant effect. The phosphorus-nitrogen system catalyzes the formation of an expanded and dense char layer, while the rigid benzene ring and silicon elements enhance the strength and continuity of the char layer, effectively insulating heat and oxygen, achieving UL94 V0 flame retardancy, and without relying on inorganic fillers that impair flowability.

[0069] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0070] (1) Breakthrough balance between process and performance:

[0071] Excellent application experience: Thanks to the selection of low-viscosity polyols and pure MDI, the operating viscosity after mixing is extremely low (e.g., below 400 mPa·s), which can flow and penetrate into the smallest gaps as quickly as water, completely solving the problem of voids between the bottom and pins of complex components.

[0072] Lightweight and strong: Through controllable foaming, the density of the product can be reduced to a lightweight level of about 0.3g / cm³. At the same time, due to the rigid benzene ring structure and the high-strength network constructed by coarse MDI, its mechanical properties such as compressive strength and tensile shear strength are improved by more than 50% compared with traditional polyurethane foam of the same density, truly achieving "light but not weak".

[0073] (2) Exceptional interfacial bonding reliability

[0074] For epoxy-based materials: Due to the strong chemical interaction between the highly active -NCO groups and the metal surface, their tensile shear strength can exceed 5 MPa, and may even lead to cohesive failure of the substrate.

[0075] For nickel steel: Through chemical bonding and high wettability, the bond strength exceeds 3 MPa, and after 1000 thermal cycles from -40°C to 100°C, the bond interface shows no delamination or cracking, meeting the most stringent reliability requirements.

[0076] (3) Excellent overall performance and reliability:

[0077] Stable V0 flame retardancy: The intrinsic flame retardant system ensures long-lasting flame retardant performance without migration or exudation. Even after long-term use or aging under high temperature and humidity, the flame retardant rating remains V0.

[0078] High modulus and high weather resistance: The polyurethane system combined with a high-modulus foam structure can effectively absorb stress and protect precision components. At the same time, polyether polyurethane has excellent resistance to hydrolysis and yellowing.

[0079] (4) Production advantages and environmental friendliness:

[0080] The formula is simplified and the production is stable: the "filler-free" system avoids problems such as uneven dispersion, sedimentation and wear on equipment caused by fillers, and the product batch consistency is extremely high.

[0081] Environmentally friendly: It can use environmentally friendly water as a foaming source, and the flame retardant system is usually halogen-free, which complies with increasingly stringent environmental regulations. Detailed Implementation

[0082] The present invention will be further described below with reference to specific embodiments.

[0083] Information on the raw materials used in this invention is shown in Table 2.

[0084] Table 2 Raw Material List

[0085]

[0086] Example 1

[0087] The high-performance foaming potting compound of the present invention comprises component A and component B, wherein the weight ratio of component A to component B is 1:0.8.

[0088] By weight, component A comprises: 2 parts of autocatalytic polyol CN-8119, 25 parts of polyether polyol TD-405 containing a rigid benzene ring structure, 30 parts of high-functionality polyester polyol HF-8730, 23 parts of liquid flame retardant TEP, 10 parts of low-viscosity polyether polyol CHE-210, 7 parts of high-functionality polyether polyol NJ-6249, 2.2 parts of foam stabilizer L6900, 0.5 parts of inhibitor LA, 0.15 parts of deionized water, and 0.15 parts of blue pigment; component B comprises 68 parts of polymethylene polyphenyl polyisocyanate PM400 and 12 parts of diphenylmethane diisocyanate MDI-50 (the functionality of component B after mixing is 2.85).

[0089] Preparation of Component A (Polyol Component):

[0090] The above-mentioned component A raw materials were added to the reactor in sequence according to the mass ratio. The preparation process parameters were as follows: the dispersion speed should be controlled at 500 rpm, the stirring time should be 45 min, the vacuum valve should be opened slowly when the vacuum is started, the vacuum should be reached at 0.090 MPa, the stirring time should be 10 min, the mixture should be filtered through a 100-mesh stainless steel filter and sealed in packaging.

[0091] Preparation of Component B (isocyanate component):

[0092] The raw materials of component B above were added to the reactor in the order of their mass fractions.

[0093] The high-performance foamed potting compound of this invention employs a two-component system design, and is applied in-situ to the battery pack using a dispensing machine for on-site potting and molding. The specific preparation process is as follows:

[0094] (1) Substrate pretreatment: The battery pack casing (nickel steel) and internal modules (epoxy-based materials) must be kept clean and dry and subjected to plasma treatment. The treatment parameters are as follows:

[0095] Plasma treatment: power 1200 W, processing speed 3 m / min;

[0096] (2) Injection and potting process:

[0097] This invention uses a low-pressure foaming dispensing machine for online mixing and potting. The specific process parameters are as follows: ① Equipment selection and parameter settings:

[0098] Preferred values ​​for equipment parameter setting range

[0099] The temperature of component A's feed tank is 30℃;

[0100] The temperature of component B's feed tank is 35℃;

[0101] The mixing head rotates at 4500 rpm;

[0102] Mixing pressure: 0.5 MPa;

[0103] Injection flow rate: 150 g / s;

[0104] Injection pressure: 0.6 MPa;

[0105] A / B mixing mass ratio 100:80;

[0106] The gun head has a diameter of 5 mm.

[0107] ② Equipment debugging:

[0108] Before starting the machine, check the material levels of components A and B to ensure sufficient material supply;

[0109] Preheat the material tank to the set temperature and circulate the heating for 30 minutes;

[0110] Calibrate the metering pump to ensure that the mixing ratio error is ≤ ±2%;

[0111] Dry run the pump to remove bubbles until the mixing head outputs a continuous, uniform, and bubble-free product.

[0112] ③ Filling and sealing operation:

[0113] Place the battery pack in the potting station and fix its position.

[0114] Height of the dispensing gun tip from the filling area: 40 mm;

[0115] Injection path: Use an "S" shaped or spiral path to ensure uniform filling;

[0116] Single injection volume: Calculated based on module volume, with a 10% expansion allowance;

[0117] Injection speed: Start fast and then slow down. Use high-speed injection (300 g / s) for the first 80% of the volume, and low-speed injection (50 g / s) for the remaining 20% ​​of the volume to prevent glue overflow.

[0118] Injection time: The injection time for a single module should be controlled within 60 seconds.

[0119] ④ Curing and molding:

[0120] Gel time control: 8 minutes (at 25°C)

[0121] Demolding time: 30 minutes (before proceeding to the next step).

[0122] Complete curing: Curing at 25°C for 24 hours.

[0123] Environmental requirements during curing: temperature 25℃, relative humidity ≤65%.

[0124] Example 2

[0125] Based on Example 1, component A contains CHE-6L33, a polyether polyol with a rigid benzene ring structure, and the rest remains unchanged.

[0126] Example 3

[0127] Based on Example 1, component A contains polyether polyols with rigid benzene ring structures, namely CHE-6L33 and TD405, and the amounts used are equal, with no other changes.

[0128] Example 4

[0129] Based on Example 1, component A, the low-viscosity polyether polyol, is CHE-204, and the rest remains unchanged.

[0130] Example 5

[0131] Based on Example 1, component B, polymethyl polyphenyl polyisocyanate, is Lupranate M70L, and diphenylmethane diisocyanate is Lupranate MI, with the rest remaining unchanged.

[0132] Example 6

[0133] Based on Example 1, the diphenylmethane diisocyanate was Lupranate M, accounting for 10 wt% of the mixture, with the rest remaining unchanged.

[0134] Example 7

[0135] Component A consists of 3 parts of self-catalytic polyol NJ-403, 27 parts of polyether polyol CHE-6L33 containing a rigid benzene ring structure, 25 parts of high-functionality polyester polyol HF-8730, 18 parts of liquid flame retardant DMMP, 9 parts of low-viscosity polyether polyol CHE-204, 8 parts of high-functionality polyether polyol NJ-8238, 1.5 parts of foam stabilizer M-8860, 0.4 parts of inhibitor FA, 0.2 parts of deionized water, and 0.15 parts of blue pigment.

[0136] Component B consists of 63 parts of polymethyl polyphenyl polyisocyanate PM400 and 9 parts of diphenylmethane diisocyanate MDI-50 (the functionality of component B after mixing is 2.875).

[0137] The weight ratio of component A to component B is 1:0.78.

[0138] Comparative Example 1

[0139] Based on Example 1, the rigid benzene ring structure polyether polyol TD405 was replaced with high-functionality polyether polyol NJ-8238, while the other conditions remained unchanged.

[0140] Comparative Example 2

[0141] Based on Example 1, the low-viscosity polyether polyol was replaced with the ordinary viscosity polyether polyol NJ-310, while the other conditions remained unchanged.

[0142] Comparative Example 3

[0143] Based on Example 1, component B was entirely made of polymethyl polyphenyl polyisocyanate, with all other conditions remaining unchanged.

[0144] Comparative Example 4

[0145] Based on Example 1, component B was entirely made of diphenylmethane diisocyanate, with all other conditions remaining unchanged.

[0146] Comparative Example 5

[0147] Based on Example 1, diphenylmethane diisocyanate accounted for 5 wt% of the mixture in component B, while other conditions remained unchanged.

[0148] Comparative Example 6

[0149] Based on Example 1, diphenylmethane diisocyanate in component B accounts for 30 wt% of the mixture, while other conditions remain unchanged.

[0150] Performance testing

[0151] The performance of the foamed potting compounds prepared in each embodiment and comparative example was tested, including density, viscosity, shear strength, and flowability. The specific test methods are as follows.

[0152] Density: Tested according to GB / T 6343-2009.

[0153] Shear force: Tested according to GB / T 7124-2008.

[0154] The test results for each sample are shown in Table 3.

[0155] Table 3 Performance test data for each sample

[0156]

[0157] As shown in Table 3, in Examples 1-6 of the present invention, by adding polyether polyols with rigid benzene ring structures, the foam can form a denser and stronger three-dimensional network structure during curing. This makes the shear force of nickel steel better than that of ordinary high-functionality polyether polyols at the same density. The addition of low-viscosity polyether polyols and the compounding of component B effectively reduce the viscosity of the system, thereby improving the overall flowability of the foam.

[0158] In Comparative Example 1, the shear force decreased significantly after the rigid benzene ring structure polyether polyol was replaced with a common high-functionality polyether polyol. This was because the cohesive strength of the foam decreased.

[0159] In Comparative Example 2, after replacing the low-viscosity polyether polyol, the shear force did not change significantly, but the overall fluidity of the foam decreased. This is because component A did not use the low-viscosity polyether polyol, resulting in an overall higher viscosity.

[0160] In Comparative Example 3, the fluidity of component B, which consisted entirely of polymethyl polyphenyl polyisocyanate, was also significantly reduced. This is because the overall viscosity of component B increased when polymethyl polyphenyl polyisocyanate was used.

[0161] In Comparative Example 4, the use of diphenylmethane diisocyanate for component B improved the flowability, but significantly reduced the shear strength. This was because the functionality of component B decreased, resulting in a decrease in the overall strength of the foam.

[0162] In Comparative Example 5, the proportion of diphenylmethane diisocyanate in component B decreased, resulting in poorer flowability of the foam. This is because the viscosity of component B increased, and the viscosity of the foam increased after mixing with component A.

[0163] In Comparative Example 6, the increased proportion of diphenylmethane diisocyanate in component B resulted in a decrease in the shear force of the foam, which is due to the decreased functionality of component B.

Claims

1. A high performance foaming potting adhesive, characterized in that, The product comprises, by weight, component A and component B; component A comprises, by weight, 2-3 parts of self-catalytic polyol, 25-30 parts of polyether polyol containing a rigid benzene ring structure, 25-30 parts of high-functionality polyester polyol, 8-10 parts of low-viscosity polyether polyol, 18-23 parts of phosphorus-containing liquid flame retardant, 6-8 parts of high-functionality polyether polyol, 1.5-2.5 parts of foam stabilizer, 0.15-0.2 parts of chemical foaming agent, and 0.4-0.5 parts of inhibitor; component B is a mixture of diphenylmethane diisocyanate and polymethylene polyphenyl polyisocyanate.

2. The high performance foaming potting adhesive according to claim 1, wherein, The polyether polyol containing a rigid benzene ring structure has a hydroxyl value of 330-400 mg KOH / g and a functionality greater than or equal to 3.

5.

3. The high performance foaming potting adhesive according to claim 1, wherein, The polyether polyol containing a rigid benzene ring structure is CHR-6L33 or TD-405.

4. The high performance foaming potting adhesive as claimed in claim 1, wherein, The diphenylmethane diisocyanate accounts for 10-15 wt% of the total weight of the mixture.

5. The high performance foaming potting adhesive as claimed in claim 1, wherein, The low-viscosity polyether polyol has a viscosity of less than 200 mPa.s at 25°C and a hydroxyl value of 107-295 mg KOH / g.

6. The high performance foaming potting adhesive as claimed in claim 1, wherein, The high-functional polyester polyol has a hydroxyl value of 250-270 mg KOH / g and a functionality of 3.

7. The high performance foaming potting adhesive as claimed in claim 1, wherein, The hydroxyl value of the self-catalytic polyol is 260-805 mg KOH / g, and the functionality is greater than or equal to 3.

8. A method for preparing the high-performance foamed potting compound according to any one of claims 1 to 7, characterized in that, Includes the following steps: (1) The raw material of component A is placed in the material cylinder of a dynamic mixer and mixed evenly, and then subjected to vacuum degassing treatment; (2) The finished component A is mixed with component B through a dispensing machine and injected into the designated cavity, and then self-leveled and foamed. After curing, a high-performance potting compound is obtained.

9. The method for preparing the high-performance foamed potting compound according to claim 8, characterized in that, In step (1), the dispersion speed is 400-500 rpm during the mixing process, the stirring time is 45±2 min, the vacuum valve needs to be opened slowly to start vacuuming, the vacuum reaches 0.090Mpa, the stirring time is 10±2 minutes, and it is filtered through a 50~100 mesh stainless steel filter and sealed in packaging.

10. The application of the high-performance foaming potting compound according to any one of claims 1 to 7 in a battery pack.

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