Electrolyte-resistant organic silicon potting adhesive and preparation method thereof

Abstract

This invention proposes an electrolyte-resistant silicone potting compound and its preparation method. The raw materials include component A: hydroxyl silicone oil, vinyl silicone oil, filler I, and functional additive I; and component B: vinyl silicone oil, phenyl silicone oil, acrylate substances, filler II, and functional additive II. The acrylate substances used in this application are preferably fluorinated acrylate-modified vinyl MQ silicone resin. The silicone potting compound prepared by this invention further promotes thermal conductivity through the bonding and thermal conduction between fillers. The potting compound provided by this invention also has good electrolyte resistance, flowability, and aging resistance, making it particularly suitable for the potting and packaging of lithium batteries.

Description

Technical Field

[0001] This invention relates to the technical field of C09J183 / 07, specifically to an electrolyte-resistant silicone potting compound and its preparation method. Background Technology

[0002] Common types of potting compounds for lithium batteries include epoxy resin, silicone resin, and polyurethane resin. Among them, silicone resin has good thermal stability, excellent electrical insulation, and stable volume after curing. In the current research and development of lightweight and compact lithium batteries, using silicone resin as a potting compound causes less damage to the lithium battery. However, silicone resin has poor corrosion resistance and its electrolyte resistance needs improvement, which limits its application and development as a lithium battery potting compound.

[0003] Chinese patent CN112480863A discloses an organosilicon potting compound that can be used with electronic components. It introduces polydopamine into a potting compound formulation containing various silicone oils and inorganic fillers, improving the adhesive's bonding ability. However, the potting compound prepared by this patent has poor resistance to electrolytes and corrosion. Chinese patent 111662550A discloses a thermally conductive silicone rubber prepared using vinyl silicone oil, hydrogen-based silicone oil, and surface-modified thermally conductive fillers. This improves the thermally conductive silicone rubber's resistance to electrolytes to some extent, but its bonding ability is poor.

[0004] Based on this, the present invention proposes an electrolyte-resistant silicone potting compound and its preparation method. The prepared silicone potting compound has strong adhesion and good resistance to electrolyte corrosion. Summary of the Invention

[0005] The first aspect of this invention provides an electrolyte-resistant silicone potting compound, the raw materials of which, by weight percentage, comprise:

[0006] Component A: 10-35% hydroxyl silicone oil, 5-20% vinyl silicone oil, 40-70% filler I, 0.5-5% functional additive I;

[0007] Component B: Vinyl silicone oil 3-10%, phenyl silicone oil 5-20%, acrylate substances 3-10%, filler II 40-70%, functional additives II 0.5-5%.

[0008] In a preferred embodiment, the raw materials for preparation comprise, by weight percentage:

[0009] Component A: 10-20% hydroxyl silicone oil, 15-20% vinyl silicone oil, 60-70% filler I, 0.5-3% functional additive I;

[0010] Component B: 8-10% vinyl silicone oil, 10-20% phenyl silicone oil, 5-10% acrylates, 60-70% filler II, and 0.5-5% functional additives II.

[0011] In a preferred embodiment, the weight ratio of component A to component B is (1-3):1. More preferably, the weight ratio of component A to component B is 2:1.

[0012] In a preferred embodiment, the hydroxyl molar percentage content of the hydroxyl silicone oil in component A is 2-4%; the vinyl silicone oil in component A has vinyl groups at both ends of the molecular chain and on the side chains of the main molecular chain.

[0013] In a preferred embodiment, the hydroxyl molar percentage content of the hydroxyl silicone oil in component A is 3.6-4%.

[0014] In a preferred embodiment, the viscosity of the vinyl silicone oil in component A is 180±10cp (25°C), and the vinyl content of the vinyl silicone oil in component A is 0.0476-0.0608mol / 100g.

[0015] In a preferred embodiment, the vinyl silicone oil in component B has vinyl groups at both ends of its molecular chain; the phenyl silicone oil has a phenyl molar percentage content of 5-30%.

[0016] In a preferred embodiment, the viscosity of the vinyl silicone oil in component B is 180±10cp (25°C), and the vinyl content of the vinyl silicone oil in component B is 0.022-0.034mol / 100g.

[0017] In a preferred embodiment, the phenyl silicone oil in component B is a phenyl hydrogen-containing silicone oil, more preferably a phenyl silicone oil with hydrogen at both ends.

[0018] In a preferred embodiment, the hydrogen molar percentage of the Si-H bonds in the hydrogen-terminated phenyl silicone oil is 0.01-0.1%.

[0019] In this application, the vinyl silicone oil in component A was purchased from Shandong Dayi Chemical Co., Ltd., model number V421-180, and the hydroxyl silicone oil was purchased from Dow Corning, model number PMX0930. Both the vinyl silicone oil and phenyl silicone oil in component B were purchased from Shandong Dayi Chemical Co., Ltd., with the vinyl silicone oil in component B being model number V401-180 and the phenyl hydrogen-containing silicone oil being model number PH201.

[0020] In a preferred embodiment, the functional additive I is selected from at least one of dispersants, anti-settling agents, reinforcing agents, catalysts, etc.; the functional additive II is selected from at least one of dispersants, anti-settling agents, reinforcing agents, inhibitors, etc.

[0021] In a preferred embodiment, the functional additive I is a catalyst. The catalyst is a platinum catalyst, more preferably, the platinum catalyst is purchased from Shanghai Neutron Star Chemical Technology Co., Ltd., and is named Castel Platinum Catalyst.

[0022] In a preferred embodiment, the functional adjuvant II is an inhibitor and a reinforcing agent. Preferably, the inhibitor accounts for 10-20% by weight of the functional adjuvant II, and the reinforcing agent accounts for 80-90% by weight of the functional adjuvant II.

[0023] More preferably, the inhibitor accounts for 16% of the weight of functional adjuvant II, and the reinforcing agent accounts for 84% of the weight of functional adjuvant II.

[0024] In a preferred embodiment, the inhibitor is selected from any one of acetylenol, methylbutynol, and dimethylhexynol, preferably dimethylhexynol.

[0025] In a preferred embodiment, the reinforcing agent is amorphous silica; more preferably, the specific surface area of ​​the amorphous silica is 150-380 m². 2 / g. More preferably, the specific surface area of ​​the amorphous silica is 300m². 2 / g, model number HL300, purchased from Huifu Nanomaterials Co., Ltd.

[0026] In a preferred embodiment, the particle size of both filler I and filler II is 0.1-100 μm.

[0027] In a preferred embodiment, both filler I and filler II are inorganic thermally conductive fillers, which are selected from at least one of silicon dioxide, aluminum oxide, silicon nitride, boron nitride, zinc oxide, aluminum nitride, and silica.

[0028] In a preferred embodiment, the filler I is silicon dioxide; more preferably, the filler I is spherical silicon dioxide.

[0029] In a preferred embodiment, the spherical silica has an average particle size of 10 μm and was purchased from Zhejiang Yamei Nanotechnology Co., Ltd., with the model number AM-SiO2-021-4.

[0030] In a preferred embodiment, the filler II is spherical alumina. More preferably, the alumina has an average particle size of 48±3μm, is of type ZHA40-C, and was purchased from Leyuan Chemical Materials Technology Co., Ltd.

[0031] During the experiment, the applicant discovered that, in components A and B, using vinyl silicone oils with vinyl groups at both ends of the molecular chain and vinyl silicone oils with vinyl groups at both ends and in the middle of the molecular chain, during the polymerization of phenyl silicone oils and vinyl silicone oils containing Si-H bonds, can form aggregates with different segmental structures and spatial structures. When mixed with fillers of different particle sizes, these aggregates can more stably bond with the fillers through their varying spatial structures. Simultaneously, the addition of hydroxyl silicone oils and other substances can further enhance the bonding ability between the filler and silicone oil through the intermolecular forces of active groups such as hydroxyl groups, thereby improving thermal conductivity and increasing the density of the potting compound. Furthermore, the applicant also used a specific surface area of ​​300 m² in component B. 2 / g of amorphous silica is used as a reinforcing agent. Amorphous silica can further fill the gaps formed by spherical silica and spherical alumina, and can also fill the spaces formed by the polymerization of silicone oil, thereby further improving the bonding density of the potting compound and reducing liquid intrusion.

[0032] In a preferred embodiment, the acrylate substance is acrylate-modified MQ silicone resin.

[0033] In a preferred embodiment, the acrylate used in the acrylate-modified MQ silicone resin is selected from at least one of fluorinated acrylates, benzene ring acrylates, alicyclic acrylates, and heterocyclic acrylates.

[0034] In a preferred embodiment, the acrylate is a fluorinated acrylate selected from at least one of 2-(trifluoromethyl)acrylate, 2,2,2-trifluoromethyl 2-methyl-2-acrylate, 2,2-difluoroethyl 2-acrylate, pentafluorophenyl acrylate, pentafluorophenyl acrylate, and 2-fluoromethyl acrylate. More preferably, the fluorinated acrylate is pentafluorophenyl acrylate.

[0035] In a preferred embodiment, the MQ resin used in the acrylate-modified MQ silicone resin is a vinyl MQ silicone resin. The vinyl MQ silicone resin has a vinyl content of 2.5-3.0%, an M:Q ratio of 0.60-0.80, and more preferably, an M:Q ratio of 0.75. It is purchased from Yandi Technology, model YDSR9070.

[0036] In a preferred embodiment, the molar ratio of the vinyl MQ silicone resin and pentafluorophenyl acrylate is 1:(0.01-0.02). More preferably, the molar ratio is 1:0.012.

[0037] In this application, the steps for modifying MQ silicone resin with acrylate are as follows: vinyl MQ silicone resin and platinum catalyst are mixed evenly at 80°C, then pentafluorophenyl acrylate is added, the temperature is lowered to 75°C, mixed, and reacted for 3 hours to obtain MQ silicone resin modified with acrylate.

[0038] The platinum catalyst was purchased from Shanghai Neutron Star Chemical Technology Co., Ltd., and its name is Castel Platinum Catalyst.

[0039] During the experiment, the applicant discovered that adding acrylate-modified MQ silicone resin, and more specifically, adding pentafluorophenyl acrylate-modified vinyl MQ silicone resin, to the raw materials for preparing silicone potting compounds not only improved the adhesive strength of the potting compound but also further enhanced its electrolyte resistance. The applicant hypothesizes that this is because the modification of vinyl MQ silicone resin with pentafluorophenyl acrylate introduces a strong hydrogen-bonding ability into the silicone potting compound system. Through intermolecular forces, this improves the adhesive strength of the potting compound. Simultaneously, the pentafluorophenyl acrylate contains pentafluorophenyl groups with high bond energy, imparting excellent oleophobic, hydrophobic, and weather-resistant properties to the potting compound. Furthermore, it protects the ester groups in the pentafluorophenyl methacrylate, reducing group decomposition and improving the corrosion resistance of the potting compound.

[0040] The second aspect of this application discloses a method for preparing an electrolyte-resistant silicone potting compound, comprising the following steps:

[0041] (1) Preparation of component A: Mix hydroxyl silicone oil, vinyl silicone oil, filler I and functional additive I in a mixer until homogeneous;

[0042] (2) Preparation of component B: Mix vinyl silicone oil, phenyl silicone oil, acrylate compounds, filler II, and functional additive II evenly in a mixer.

[0043] (3) Mix component A and component B in a weight ratio of (3-1):1 and cure at 50-70°C to obtain the potting compound.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. This invention incorporates vinyl silicone oil with vinyl groups at both ends of its molecular chain and vinyl silicone oil with vinyl groups at both ends and in the middle of its molecular chain into the potting compound. Through the polymerization process of vinyl silicone oil with phenyl silicone oil and hydroxyl silicone oil, it forms a three-dimensional aggregate with different chain segment structures and chain segment spatial structures, which better combines with the added filler and improves the integrity and bonding density of the potting compound.

[0046] 2. This invention adds spherical silica with an average particle size of 10 μm and spherical aluminum oxide with an average particle size of 48 ± 3 μm to the potting compound, and also adds materials with a specific surface area of ​​300 m². 2 / g of amorphous silica forms a tightly overlapping, small-pore potting compound filler through the difference in particle size, which improves adhesion and thermal conductivity, further promotes thermal conductivity, and also further increases the bonding density of the potting compound, reducing the intrusion of liquids, especially electrolytes.

[0047] 3. This invention incorporates pentafluorophenyl acrylate-modified vinyl MQ resin into the potting compound. This not only improves the adhesive strength of the potting compound but also enhances its oleophobicity, hydrophobicity, and weather resistance through the pentafluorophenyl structure. It also protects the hydrophilic and easily decomposable groups in the potting compound, thereby improving its corrosion resistance.

[0048] 4. The potting compound prepared by this invention also has good thermal conductivity, good electrolyte resistance, flowability and aging resistance, and is particularly suitable for potting and packaging lithium batteries. Detailed Implementation

[0049] Example 1

[0050] The first aspect of this embodiment proposes an electrolyte-resistant silicone potting compound, the raw materials of which, by weight percentage, include:

[0051] Component A: 12% hydroxyl silicone oil, 18% vinyl silicone oil, 69.2% spherical silica, 0.8% platinum catalyst;

[0052] Component B: 8% vinyl silicone oil, 15% phenyl silicone oil, 8% acrylate substances, 64% spherical silica, and 5% functional additive II.

[0053] The hydroxyl molar percentage content of the hydroxyl silicone oil in component A is 3.6-4%, purchased from Dow Corning, model PMX0930.

[0054] Component A, a vinyl silicone oil, has vinyl groups at both ends of its molecular chain and on the side chains of its main chain. It has a viscosity of 180±10 cp (25℃) and a vinyl content of 0.0476-0.0608 mol / 100g. It was purchased from Shandong Dayi Chemical Co., Ltd., model number V421-180.

[0055] The average particle size of the spherical silica in component A is 10 μm, and it was purchased from Zhejiang Yamei Nanotechnology Co., Ltd., model AM-SiO2-021-4.

[0056] The platinum catalyst in component A was purchased from Shanghai Neutron Star Chemical Technology Co., Ltd., and its name is Castel Platinum Catalyst.

[0057] The vinyl silicone oil in component B has vinyl groups at both ends of its molecular chain. The viscosity of the vinyl silicone oil is 180±10cp (25℃), and the vinyl content is 0.022-0.034mol / 100g. It was purchased from Shandong Dayi Chemical Co., Ltd., and the model number is V401-180.

[0058] The phenyl silicone oil in component B is a phenyl silicone oil with hydrogen at both ends, wherein the phenyl molar percentage content is 5-30% and the hydrogen molar percentage of Si-H bonds is 0.01-0.1%, purchased from Shandong Dayi Chemical Co., Ltd., model number PH201.

[0059] The spherical aluminum oxide particles had an average particle size of 48±3μm, were model ZHA40-C, and were purchased from Leyuan Chemical Materials Technology Co., Ltd.

[0060] Functional additive II consists of an inhibitor and a reinforcing agent. The inhibitor accounts for 16% of the weight of functional additive II, while the reinforcing agent accounts for 84%. The inhibitor is dimethylhexynol, and the reinforcing agent is amorphous silica with a specific surface area of ​​300 m². 2 / g, model number HL300, purchased from Huifu Nanomaterials Co., Ltd.

[0061] The acrylate material is a pentafluorophenyl acrylate modified vinyl MQ silicone resin. The preparation steps are as follows: after mixing vinyl MQ silicone resin and platinum catalyst at 80°C, add pentafluorophenyl acrylate, cool to 75°C, mix, and react for 3 hours to obtain acrylate modified MQ silicone resin.

[0062] The molar ratio of vinyl MQ silicone resin to pentafluorophenyl acrylate is 1:0.012, and the molar ratio of platinum catalyst to vinyl MQ silicone resin is 0.003:1. The vinyl content of the vinyl MQ silicone resin is 2.5-3.0%, and the M:Q ratio is 0.75. It was purchased from Yandi Technology, model YDSR9070. The CAS number of the pentafluorophenyl acrylate is 19089-73-7, and the platinum catalyst was purchased from Shanghai Neutron Star Chemical Technology Co., Ltd., named Castel Platinum Catalyst.

[0063] The second aspect of this embodiment proposes a method for preparing an electrolyte-resistant silicone potting compound, comprising the following steps:

[0064] (1) Preparation of component A: Hydroxyl silicone oil, vinyl silicone oil, spherical silica, and platinum catalyst are mixed evenly in a mixer;

[0065] (2) Preparation of component B: Mix vinyl silicone oil, phenyl silicone oil, acrylate compounds, spherical silica, and functional additive II evenly in a mixer.

[0066] (3) Mix component A and component B in a weight ratio of 2:1 and cure at 65°C to obtain the potting compound.

[0067] Example 2

[0068] The first aspect of this embodiment discloses an electrolyte-resistant silicone potting compound, and the second aspect discloses a method for preparing the electrolyte-resistant silicone potting compound. The raw materials and preparation method are the same as in Example 1, except that the vinyl silicone oil in component A is a vinyl silicone oil with vinyl groups at both ends of its molecular chain, with a viscosity of 180±10cp (25℃) and a vinyl content of 0.022-0.034mol / 100g, purchased from Shandong Dayi Chemical Co., Ltd., model V401-180; no reinforcing agent is added to component B, and the amount of spherical alumina added to component B is 68.17%.

[0069] Example 3

[0070] The first aspect of this embodiment discloses an electrolyte-resistant silicone potting compound, and the second aspect discloses a method for preparing the electrolyte-resistant silicone potting compound. The raw materials and preparation method are the same as in Example 1, except that no acrylate substances are added to component B, and the content of phenyl silicone oil in component B is 19%, and the content of vinyl silicone oil is 12%.

[0071] Performance testing

[0072] The potting compounds prepared in Examples 1-3 were tested for thermal conductivity, viscosity, electrolyte resistance, and electrolyte absorption rate. The data are recorded in Table 1.

[0073] 1. Thermal conductivity: Tested according to ASTM D5470-2006.

[0074] 2. Viscosity: Tested in accordance with GB / T2794-2013.

[0075] 3. Electrolyte resistance: Apply potting compound evenly to the silicon substrate. After the potting compound cures, it forms a 0.2-0.3mm thick adhesive layer. Test the 90° peel strength. Then, immerse the silicon substrate with the potting compound in an electrolyte at 85°C for 200 hours and 300 hours respectively, and test the 90° peel strength.

[0076] 4. Electrolyte Absorption Rate: The cured potting compound is weighed as M1. The potting compound is placed in an electrolyte vapor atmosphere at 70℃ for 5 days, 1 month, and 2 months, and weighed again as M2. The absorption rate is calculated based on the change in mass. Absorption Rate = (M2 - M1) / M1 * 100%.

[0077] Table 1

[0078]

Claims

1. An electrolyte-resistant organic silicone potting compound, characterized by, The raw materials for preparation, by weight percentage, include: Component A: 12% hydroxyl silicone oil, 18% vinyl silicone oil, 69.2% spherical silica, 0.8% platinum catalyst; Component B: 8% vinyl silicone oil, 15% phenyl silicone oil, 8% acrylate substances, 64% spherical aluminum oxide, and 5% functional additive II; The hydroxyl silicone oil in component A was purchased from Dow Corning. Among them, the vinyl silicone oil in component A has vinyl groups at both ends of the molecular chain and on the side chains of the main molecular chain, with a viscosity of 180±10cp and a vinyl content of 0.0476-0.0608mol / 100g. The average particle size of the spherical silica in component A is 10 μm; the vinyl silicone oil in component B has vinyl groups at both ends of its molecular chain, a viscosity of 180 ± 10 cp, and a vinyl content of 0.022-0.034 mol / 100g, and was purchased from Shandong Dayi Chemical. The phenyl silicone oil in component B is a phenyl silicone oil with hydrogen at both ends. The average particle size of the spherical aluminum oxide is 48±3μm; Functional adjuvant II consists of inhibitors and reinforcing agents, with the inhibitor accounting for 16% of the weight of functional adjuvant II and the reinforcing agent accounting for 84% of the weight of functional adjuvant II. The inhibitor is dimethylhexynol and the reinforcing agent is amorphous silica with a specific surface area of 300 m 2 / g. The acrylate material is a pentafluorophenyl acrylate modified vinyl MQ silicone resin. The preparation steps are as follows: after mixing vinyl MQ silicone resin and platinum catalyst at 80°C, add pentafluorophenyl acrylate, cool down to 75°C, mix, and react for 3 hours to obtain acrylate modified MQ silicone resin. The molar ratio of vinyl MQ silicone resin to pentafluorophenyl acrylate is 1:0.012, and the molar ratio of platinum catalyst to vinyl MQ silicone resin is 0.003:

1. The vinyl MQ silicone resin contains 2.5-3.0% vinyl content and has an M to Q ratio of 0.

75. It was purchased from Yandi Technology and its model number is YDSR9070.

2. A method of producing the electrolyte-resistant silicone potted adhesive according to claim 1, characterized by, Includes the following steps: (1) Preparation of component A: Mix hydroxyl silicone oil, vinyl silicone oil, filler I, and functional additive I in a mixer until homogeneous; (2) Preparation of component B: Mix vinyl silicone oil, phenyl silicone oil, acrylate compounds, filler II, and functional additive II evenly in a mixer; (3) Mix component A and component B in a weight ratio of (3-1):1 and cure at 50-70°C to obtain the potting compound.

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