High-waterproof pouring sealant and preparation method thereof

Abstract

The invention relates to the technical field of waterproof pouring sealants, in particular to a high-waterproof pouring sealant and a preparation method thereof. A conventional waterproof pouring sealant is easy to generate a synergistic effect of electrochemical corrosion and water vapor permeation in a use process and is relatively short in service life. In order to solve the technical problems, the invention provides the high-waterproof pouring sealant, hydrotalcite and zeolite are compounded to serve as a composite ion capturing agent, while the composite ion capturing agent adsorbs moisture and captures ions, micro-nano particles of the composite ion capturing agent also effectively fill a cross-linked network of epoxy resin, a more compact barrier structure is formed, and the high-waterproof pouring sealant has good waterproof performance. Therefore, the packaging colloid has extremely low water absorption and higher volume resistivity, and the insulation reliability of a packaged component in a long-term humid environment is effectively ensured.

Description

Technical Field

[0001] This invention relates to the field of waterproof potting compound technology, specifically to a highly waterproof potting compound and its preparation method. Background Technology

[0002] In the era of intelligent technology, sensors, as core components for sensing environmental parameters, directly determine the reliability of intelligent systems based on their performance stability. However, the long-term reliability of sensors in humid and hot environments remains a key technological bottleneck restricting their application. The penetration of water molecules and moisture can trigger multiple failure mechanisms: on the one hand, moisture intrusion causes the insulating material to absorb moisture and expand, resulting in changes in electrode spacing or insulation layer breakdown; on the other hand, corrosive media such as chloride ions dissolved in water can undergo electrochemical reactions with metal electrodes, accelerating plating corrosion and signal drift. Taking the voltage / temperature sensor in the battery management system (BMS) of new energy vehicles as an example, the persistent high humidity (relative humidity ≥85%) and condensation conditions in its working environment allow water molecules to penetrate through the micropores of the epoxy potting layer and react with LiPF6 in the electrolyte to generate acidic substances such as HF. This leads to a corrosion rate of 0.5-1.2 μm / year for the copper foil current collector, directly causing a surge in contact resistance and the risk of thermal runaway.

[0003] In existing technologies, the following three main solutions are used for waterproof encapsulation of sensors: 1) Raw material pretreatment technology, which involves dehydrating epoxy resin at 120℃ for 4 hours in a vacuum drying oven. However, this process can only reduce the free water content to below 0.05%, and its effect on removing bound water is limited; 2) Physical barrier technology, which uses Parylene vacuum coating to form a dense protective layer of 10-20μm. However, it is prone to microcracks under temperature cycling conditions (-40℃~125℃); 3) Chemical barrier technology, which modifies the potting compound by adding paraffin-based hydrophobic agents. However, these materials have poor compatibility with epoxy resin, often leading to a decrease in mechanical properties of more than 30%. None of the above solutions fundamentally solve the problem of the synergistic effect of ion migration and water vapor permeation. Summary of the Invention

[0004] Problems with existing technologies: Conventional waterproof potting compounds are prone to synergistic effects of electrochemical corrosion and water vapor penetration during use, resulting in poor waterproof performance. To address these problems, this invention provides a highly waterproof potting compound comprising component A and component B, wherein the weight ratio of component A to component B is 3:1 to 4:1. Component A, by weight, comprises the following components: Epoxy resin 80-90%; Diluent I: 1.5-4.5%; Filler content 6-15%; Anti-settling agent 0.3-0.5%; Ion scavenger 0.5-2%; Defoamer 0.1-0.5%; Component B, by weight, comprises the following components: Alicyclic amines account for 40-50%; 40-50% of diaminodicyclohexylmethane derivatives; Diluent II 10-20%.

[0005] Preferably, the epoxy resin is epoxy resin E44 or epoxy resin E51, and the epoxy equivalent of the epoxy resin is 180-250 g / mol.

[0006] Preferably, the diluent I includes one or both of butylene glycol diglycidyl ether and ethylene glycol diglycidyl ether.

[0007] Preferably, the filler comprises one or two of alumina and silica powder (10~20μm).

[0008] Preferably, the anti-settling agent comprises one or both of fumed silica or organobentonite.

[0009] Preferably, the ion scavenging agent is composed of hydrotalcite and zeolite in a mass ratio of 1:1 to 3:1.

[0010] Preferably, the defoamer is an organosilicon defoamer.

[0011] Preferably, the diaminodicyclohexylmethane derivative includes one or both of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane or 4,4'-diaminodicyclohexylmethane.

[0012] Preferably, the diluent II is benzyl alcohol.

[0013] The present invention has the following beneficial effects: (1) This invention uses a composite ion scavenger made of hydrotalcite and zeolite (preferably in a mass ratio of 2:1), which produces a significant synergistic effect among the components. Zeolite molecular sieves can efficiently physically adsorb water molecules that invade the packaging system, greatly reducing the humidity of the internal environment; while hydrotalcite chemically captures and firmly fixes corrosive ions such as Cl⁻ and SO4²⁻ brought in by water through ion exchange, thereby fundamentally eliminating the main destructive factors of damp heat aging. As shown in Table 1, Examples 1-5 of this invention can pass the rigorous test of 85℃ / 85%RH for 1000 hours, while Comparative Examples 1, 2 and 5 fail due to the lack of this synergistic protection mechanism. (2) In addition to adsorbing moisture and capturing ions, the composite ion scavenger of the present invention also effectively fills the cross-linked network of epoxy resin with its micro-nano particles, forming a denser barrier structure. Together, these factors result in the encapsulated colloid having an extremely low water absorption rate (the 24-hour water absorption rate of Examples 1-5 is only 0.12%~0.18%) and an extremely high volume resistivity (>4.8×10⁻⁶). 14 (Ω·cm), which ensures that the encapsulated components can maintain excellent insulation performance and high reliability in long-term humid environments, far exceeding the comparative solution; (3) By using alumina and silica powder as functional fillers, this invention combines the dual advantages of alumina (high hardness, high thermal conductivity, high insulation) and silica powder (good flowability, low shrinkage, effective filling), so that the cured adhesive layer has both high Shore hardness and good construction compatibility, overcoming the defect of uneven performance when using a single filler (Comparative Examples 3 and 4). (4) The cross-linked network formed by the epoxy-amine curing system of the present invention has excellent thermal stability, which enables all the examples and comparative products to pass the high temperature test of 200℃ and the low temperature test of -40℃, and has better environmental adaptability. Detailed Implementation The present invention will be described in detail below with reference to embodiments. However, it should be understood that the following embodiments are merely illustrative examples of implementation of the present invention and are not intended to limit the scope of the present invention.

[0014] The fillers used in Examples 1-5 and Comparative Examples 1-4 of this invention are all composed of alumina and silica powder in a mass ratio of 1:1.

[0015] The alumina used in Examples 1-5 and Comparative Examples 1-4 of this invention is product model AL-100, purchased from Zhengzhou Research Institute of Aluminum Corporation of China Limited, with a D50 particle size of approximately 3 μm.

[0016] The silicon micropowder used in Examples 1-5 and Comparative Examples 1-4 of this invention has the product model: LR-SiO2-3μm, and the D50 particle size is approximately 3μm.

[0017] The fumed silica used in Examples 1-5 and Comparative Examples 1-4 of this invention, product model: LR-SiO2-G, was purchased from Jiangsu Lianrui New Materials Co., Ltd.

[0018] The defoamer used in Examples 1-5 and Comparative Examples 1-4 of this invention is an organosilicon defoamer, product model: LR-Si-DF100, purchased from Jiangsu Lianrui New Materials Co., Ltd.

[0019] The alicyclic amine compounds used in Examples 1-5 and Comparative Examples 1-4 of this invention are Versamine C from Corning Chemical Co., Ltd., with an amine value of 200-300 mg KOH / g.

[0020] The zeolite used in Examples 1-5 and Comparative Examples 1-4 of this invention is 13X zeolite molecular sieve, chemical formula: Na. 86 [Al 86 Si 104 O 384 ]·224H2O.

[0021] The hydrotalcite used in Examples 1-5 and Comparative Examples 1-4 of this invention, product model: HT-LDH-1 (magnesium aluminum hydrotalcite), was purchased from Zhejiang Huatai New Materials Co., Ltd. Example

[0022] A highly waterproof potting compound comprises component A and component B, wherein the weight ratio of component A to component B is 3:1. Component A, by weight, has the following composition: Epoxy resin E44 (epoxy equivalent of 180 g / mol) 80%; Butylene glycol diglycidyl ether 1.5%; 6% of filler material; Fumed silica 0.3%; Ion scavenger 0.5%; Defoamer 0.1%; Component B, by weight, has the following composition: Alicyclic amines (amine value 200 mg KOH / g): 40%; 40% of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane; 10% benzyl alcohol.

[0023] The ion scavenging agent is composed of hydrotalcite and zeolite in a mass ratio of 2:1. Example

[0024] A highly waterproof potting compound comprises component A and component B, wherein the weight ratio of component A to component B is 4:1. Component A, by weight, has the following composition: Epoxy resin E51 (epoxy equivalent of 200 g / mol) 90%; Ethylene glycol diglycidyl ether 4.5%; 15% filler; Fumed silica 0.5%; ion scavenger 2%; Defoamer 0.5%; Component B, by weight, has the following composition: Alicyclic amines (amine value 250 mg KOH / g) 50%; 50% 4,4'-Diaminodicyclohexylmethane; Benzyl alcohol 20%.

[0025] The ion scavenging agent is composed of hydrotalcite and zeolite in a mass ratio of 2:1. Example

[0026] A highly waterproof potting compound comprising component A and component B, wherein the weight ratio of component A to component B is 3.5:1, and component A, by weight, has the following composition: Epoxy resin E51 (epoxy equivalent of 250 g / mol) 85%; Butylene glycol diglycidyl ether 2.5%; 10% filler; Fumed silica 0.4%; ion scavenger 1%; Defoamer 0.3%; Component B, by weight, has the following composition: Alicyclic amines (amine value 300 mg KOH / g): 45%; 4,4'-Diaminodicyclohexylmethane 45%; Benzyl alcohol 15%.

[0027] The ion scavenging agent is composed of hydrotalcite and zeolite in a mass ratio of 2:1.

[0028] Example 4 is the same as Example 1, except that the ion scavenger in Example 4 is composed of hydrotalcite and zeolite in a mass ratio of 1:1.

[0029] Example 5 is the same as Example 1, except that the ion scavenger in Example 5 is composed of hydrotalcite and zeolite in a mass ratio of 3:1.

[0030] Comparative Example 1 is the same as Example 1, except that the ion scavenger in Comparative Example 1 is only hydrotalcite.

[0031] Comparative Example 2 is the same as Example 1, except that the ion scavenger in Comparative Example 2 is only zeolite.

[0032] Comparative Example 3 is the same as Example 1, except that the filler in Comparative Example 3 is only alumina.

[0033] Comparative Example 4 is the same as Example 1, except that the filler in Comparative Example 3 is only silica powder.

[0034] Comparative Example 5 is the same as Example 1, except that no ion scavenging agent was added in Comparative Example 5.

[0035] Comparative Example 6 is Dow Corning Silastic series potting compound, grade DC 527.

[0036] Specific applications The high waterproof potting compounds obtained in Examples 1-5 and Comparative Example 4 of this invention were subjected to relevant performance tests. Components A and B corresponding to the examples and comparative examples were stirred and mixed evenly at 200-300 rpm according to the formula amount. Then, components A and B corresponding to the examples and comparative examples were mixed evenly according to the formula amount. Then, they were used as glue for automatic dispensing machine for dispensing. After dispensing, they were cured at 120°C for 4 hours under nitrogen protection to obtain sealant layers of the same thickness.

[0037] The sealant layers obtained in the examples and comparative examples were then tested for moisture and heat resistance, waterproofing, and insulation properties, respectively. The specific tests are as follows: Moisture and heat resistance: The test was conducted according to the international standard IEC60068-2-67, simulating a humid environment (85℃ / 85CRH, 1000h). The test results are shown in Table 1.

[0038] Waterproofing performance: The testing standard is ASTM D570. Waterproofing performance is evaluated based on the water absorption rate; the higher the water absorption rate, the worse the waterproofing performance. Specific test results are shown in Table 1.

[0039] Shore hardness: The test standard is ASTM D2240. The test results are shown in Table 1.

[0040] Insulation performance: The test standard is IEC 60243. The test results (volume resistivity Ω·cm) are shown in Table 1.

[0041] High temperature resistance: The test standard is GB / T 3512-2014 (200℃ / 24h). The test results are shown in Table 1.

[0042] Low-temperature resistance: The test standard is GB / T 15256-2014 (-40℃ / 72h). The test results are shown in Table 1.

[0043] Table 1 , As shown in Table 1, the performance advantages of Examples 1-5 do not stem from a simple combination of single components, but rather from the rational and complementary combination of the components, achieving synergistic effects. The ion traps in Examples 1-5 are all composed of hydrotalcite and zeolite. Zeolite, like a "sponge," uses its large specific surface area and microporous structure to physically adsorb and lock in intruding water molecules, reducing humidity within the system. Hydrotalcite, like a "targeted detoxifier," chemically captures and firmly fixes corrosive anions (such as Cl⁻, SO₄²⁻) brought in by water through its interlayer ion exchange capacity, preventing them from damaging the epoxy network and corroding electronic components. As shown in Table 1, this synergistic effect directly results in extremely low water absorption (~0.15%), excellent resistance to damp heat (passes 1000h), and extremely high volume resistivity (>5.0×10¹). 4 Ω·cm).

[0044] Comparative Example 1 (hydrotalcite only): It can fix ions, but cannot effectively dehumidify. Water molecules will still damage the material, resulting in failure to resist damp heat and high water absorption.

[0045] Comparative Example 2 (zeolite only): It can adsorb water but cannot fix ions. The concentrated ions actually exacerbate corrosion and ionic conductivity, leading to failure in resistance to damp heat and poor insulation.

[0046] Comparative Example 5 (without ion scavenger): The system has no defense against water and ions, its performance is completely degraded, and its water absorption rate is as high as 0.60%.

[0047] Therefore, no single-component ion scavenger can replace the synergistic protective effect produced by the combination of the two.

[0048] The fillers in Examples 1-5 of this invention are all composed of alumina and silica powder in a 1:1 mass ratio. Alumina provides high hardness, high thermal conductivity, and excellent insulation. Silica powder provides good flowability, low curing shrinkage, and a certain toughening effect, and can effectively fill voids and help reduce water absorption. The compound filler gives the potting compound high hardness and good processability, and lays the foundation for excellent insulation.

[0049] Comparative Example 3 (alumina only): It has the highest hardness (88), but may have sacrificed some fluidity and internal stress. Its insulation and water resistance (0.25%) are not as good as the compound filler.

[0050] Comparative Example 4 (silicon micropowder only): It had the lowest hardness (82), insufficient overall mechanical strength, and its insulation and water resistance (0.22%) also failed to reach the optimal level of the compound filler.

[0051] This shows that a single filler cannot simultaneously meet the multifaceted performance requirements of potting compounds.

[0052] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A highly waterproof potting compound, characterized in that, The product comprises component A and component B, wherein the weight ratio of component A to component B is 3:1 to 4:

1. Component A, by weight, comprises the following components: Epoxy resin 80-90%; Diluent I: 1.5-4.5%; Filler content 6-15%; Anti-settling agent 0.3-0.5%; Ion scavenger 0.5-2%; Defoamer 0.1-0.5%; Component B, by weight, comprises the following components: Alicyclic amines account for 40-50%; 40-50% of diaminodicyclohexylmethane derivatives; Diluent II 10-20%.

2. The highly waterproof potting compound according to claim 1, characterized in that, The epoxy resin is epoxy resin E44 or epoxy resin E51, and the epoxy equivalent of the epoxy resin is 180-250 g / mol.

3. The highly waterproof potting compound according to claim 1, characterized in that, The diluent I includes one or both of butylene glycol diglycidyl ether and ethylene glycol diglycidyl ether.

4. The highly waterproof potting compound according to claim 1, characterized in that, The filler includes one or two of alumina and silica micropowder (10~20μm).

5. The highly waterproof potting compound according to claim 1, characterized in that, The anti-settling agent includes one or both of fumed silica or organobentonite.

6. The highly waterproof potting compound according to claim 1, characterized in that, The ion scavenging agent is composed of hydrotalcite and zeolite in a mass ratio of 1:1 to 3:

1.

7. The highly waterproof potting compound according to claim 1, characterized in that, The defoamer is an organosilicon defoamer.

8. The highly waterproof potting compound according to claim 1, characterized in that, The diaminodicyclohexylmethane derivative includes one or both of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane or 4,4'-diaminodicyclohexylmethane.

9. The highly waterproof potting compound according to claim 1, characterized in that, The diluent II is benzyl alcohol.

10. A method for packaging electronic components, characterized in that, The highly waterproof potting compound described in any one of claims 1-9 is used as the encapsulating adhesive.