Low-viscosity high-permeability epoxy resin adhesive, preparation method and application thereof

Abstract

This invention belongs to the field of epoxy resin technology, specifically relating to a low-viscosity, high-penetration epoxy resin adhesive, its preparation method, and its application. The prepared low-viscosity, high-penetration epoxy resin adhesive comprises the following components in parts by weight: 45-55 parts bisphenol F type epoxy resin, 15-20 parts bis((3,4-epoxycyclohexyl)methyl)adipate, 25-35 parts curing agent, 5-15 parts reactive diluent, 3-8 parts toughening agent, 0.5-1 part nano-silica, 0.5-2 parts siloxane coupling agent, 1-2 parts accelerator, and 0-0.5 parts penetrant. The preparation method includes the following steps: S1. Mixing and dehydration; S2. Ultrasonic dispersion for 20 min to obtain a mixture; S3. Heating the accelerator to 60℃ to melt, then adding the nano-silica and stirring for 1 h before adding it to the mixture obtained in step S2, and mixing evenly; S4. Curing and degassing to obtain the product. The low-viscosity, high-penetration epoxy resin prepared by this invention has low viscosity, high tensile strength, and high penetration depth, which can meet the needs of multiple application scenarios. The preparation method is simple and easy to industrialize.

Description

Technical Field

[0001] This invention belongs to the field of epoxy resin technology, specifically relating to a low-viscosity, high-penetration epoxy resin adhesive, its preparation method, and its application. Background Technology

[0002] Epoxy resin adhesives are widely used in many fields such as electronics, machinery, and construction due to their excellent bonding properties, mechanical properties, and chemical stability. However, traditional epoxy resin adhesives often suffer from problems such as high viscosity and poor penetration.

[0003] In the field of electronic packaging, with the miniaturization and integration of electronic components, the requirements for the penetration performance of packaging materials are becoming increasingly stringent. High-viscosity epoxy resin adhesives struggle to fully penetrate into tiny gaps and pores, resulting in loose encapsulation and affecting the stability and reliability of electronic components. In the field of building reinforcement, for some concrete structures with microcracks, epoxy resin adhesives with low penetration performance cannot effectively fill the cracks, thus failing to achieve the desired reinforcement effect.

[0004] Low-viscosity, high-penetration epoxy resin adhesives should have the following characteristics: 1. Ultra-low viscosity and high fluidity The viscosity is typically 300–1300 mPa·s (23°C), which significantly enhances the migration ability in capillary pores.

[0005] 2. Strong penetration and deep consolidation Through a "penetration-diffusion-bonding" mechanism, high-pressure injection can fill weak structures.

[0006] 3. Excellent mechanical properties and durability High compressive strength, good toughness, resistance to acid, alkali and salt corrosion, strong stability during damp heat aging, and wide applicable temperature range (~40℃ to 100℃).

[0007] 4. Environmentally friendly and construction-friendly Low VOC emissions, supports room temperature curing, and some products can even be cured at ultra-low temperatures (below ~10℃).

[0008] CN108300164B provides a water-based curing agent, a water-based epoxy resin composition, and their application in high-penetration waterproof and reinforcing coatings. The water-based epoxy resin composition comprises the following components in parts by weight: 100 parts epoxy resin, 5-30 parts reactive diluent, 130-170 parts water-based curing agent, and 1-5 parts penetration enhancer. The water-based curing agent is prepared by reacting phenol, polyetheramine, and polyamine in a molar ratio of 1:(0.8-1):(0.8-1.5) with formaldehyde through the following reaction: phenol, polyetheramine, and a first portion of formaldehyde in an equimolar amount with the polyetheramine undergo a first-step Mannich reaction; then, the remaining phenol, the polyetheramine-phenol reaction product, the polyamine compound, and the second portion of formaldehyde undergo a second-step Mannich reaction to obtain the water-based curing agent. The molar ratio of the polyamine compound to the second portion of formaldehyde is 1:(1-1.2); the molecular weight of the polyetheramine is 1000-2100. However, its performance is not ideal and cannot meet the demanding requirements of electronic packaging.

[0009] Currently, while some low-viscosity epoxy resin products are available on the market, they often sacrifice other properties, such as bond strength and chemical resistance, while maintaining low viscosity. Therefore, developing an epoxy resin adhesive that can maintain low viscosity and high penetration performance, while also possessing good overall performance, is of significant practical importance. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention provides a low-viscosity, high-penetration epoxy resin adhesive, comprising the following components in parts by weight: 45-55 parts bisphenol F epoxy resin, 15-20 parts bis((3,4-epoxycyclohexyl)methyl)adipate, 25-35 parts curing agent, 5-15 parts reactive diluent, 3-8 parts toughening agent, 0.5-1 part nano-silica, 0.5-2 parts siloxane coupling agent, 1-2 parts accelerator, and 0-0.5 parts penetrant. Bisphenol F epoxy resin has a low viscosity, approximately 60% lower than bisphenol A epoxy resin, a low benzene ring density, high molecular chain flexibility, and improved penetration efficiency. The combination with bis((3,4-epoxycyclohexyl)methyl)adipate compensates for the slightly lower heat resistance of bisphenol F epoxy resin. The combined effect lowers viscosity and achieves a balance between toughness and rigidity.

[0011] Furthermore, the curing agent is a polyetheramine-modified epoxy curing agent (Suzhou Hengsite C-16). The polyetheramine-modified epoxy curing agent extends the curing agent molecular chain, reduces the crosslinking density, and increases the elongation at break of the cured product.

[0012] Further, the reactive diluent is 1,4-cyclohexanediethanol diglycidyl ether or an ionic liquid diluent system, wherein the ionic liquid diluent system is a mixture of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and butyl glycidyl ether in a 1:1 mass ratio. The reactive diluent reduces the viscosity of the epoxy resin adhesive, improving its flowability and penetration properties. It can chemically react with the epoxy resin and participate in the curing process, unlike inactive diluents which volatilize after curing, thus ensuring the performance stability of the resin adhesive. When the reactive diluent contains an ionic liquid, the anions and cations in the ionic liquid have good compatibility with inorganic fillers, and the organic groups have excellent compatibility with the resin matrix, thus possessing the dual functions of dilution and improving product compatibility.

[0013] Furthermore, the toughening agent is at least one of carboxyl-terminated liquid nitrile butadiene rubber and hyperbranched polylysine. In the carboxyl-terminated liquid nitrile butadiene rubber, the carboxyl groups pre-react with the epoxy groups to form a cross-linked structure, which can be dispersed in the continuous phase of the epoxy resin, absorbing and dispersing energy, thereby improving the toughness of the resin. It also works in conjunction with the diluent to reduce viscosity while maintaining cross-linking density. Hyperbranched polylysine has numerous branching points within its molecule, making its molecular chains less prone to entanglement. It has low viscosity and excellent flowability, thus providing both toughening and dilution effects.

[0014] Furthermore, the penetrant is isopropanol. Isopropanol has low surface tension, promotes capillary action, and has low viscosity, thus providing the product with good penetration properties.

[0015] Furthermore, the accelerator is 2-ethyl-4-methylimidazole. 2-ethyl-4-methylimidazole can improve the curing speed and the properties of the cured product.

[0016] Furthermore, the siloxane coupling agent is γ-aminopropyltriethoxysilane.

[0017] Furthermore, the aforementioned epoxy resin adhesives have applications in the construction and electronics fields.

[0018] The present invention also provides a method for preparing the epoxy resin adhesive, comprising the following steps: S1. Bisphenol F type epoxy resin, bis((3,4-epoxycyclohexyl)methyl) adipate, and reactive diluent are mixed and dehydrated at 50°C; S2. Add toughening agent and siloxane coupling agent to the mixture obtained in step S1, and ultrasonically disperse at 60°C for 20 min to obtain a mixture; S3. Heat the accelerator to 60℃ to melt it, then add it to the nano silica and stir for 1 hour. Add it to the mixture obtained in step S2 and mix it evenly. Mixing the melted accelerator with the nano silica allows the accelerator to be adsorbed into the nanopores. Use it slowly during the reaction to control the reaction rate and achieve better curing effect. S4. Cool down to 40℃, add curing agent and penetrant in sequence, continue to react for 2~3 hours, and after degassing, obtain low viscosity high penetration epoxy resin adhesive.

[0019] The low-viscosity, high-penetration epoxy resin adhesive prepared by this invention has low viscosity, high tensile strength, and high penetration depth, which can meet the needs of multiple application scenarios. The preparation method is simple and easy to industrialize. Detailed Implementation

[0020] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention. Example

[0021] A low-viscosity, high-penetration epoxy resin adhesive comprises the following components in parts by weight: 50 kg of bisphenol F type epoxy resin, 18 kg of bis((3,4-epoxycyclohexyl)methyl)adipate, 30 kg of curing agent, 10 kg of reactive diluent, 5 kg of toughening agent, 1 kg of nano silica, 1 kg of siloxane coupling agent, 2 kg of accelerator, and 0 kg of penetrant.

[0022] The curing agent is a polyetheramine modified epoxy curing agent (Suzhou Hengsite C-16 type).

[0023] The active diluent is 1,4-cyclohexanediethanol diglycidyl ether.

[0024] The toughening agent is a carboxyl-terminated liquid nitrile rubber.

[0025] The accelerator is 2-ethyl-4-methylimidazole.

[0026] The siloxane coupling agent is γ-aminopropyltriethoxysilane.

[0027] The preparation method of the above-mentioned epoxy resin adhesive includes the following steps: S1. Bisphenol F type epoxy resin, bis((3,4-epoxycyclohexyl)methyl) adipate, and reactive diluent are mixed and dehydrated at 50°C; S2. Add toughening agent and siloxane coupling agent to the mixture obtained in step S1, and ultrasonically disperse at 60°C for 20 min to obtain a mixture; S3. Heat the accelerator to 60°C to melt it, then add nano-silica and stir for 1 hour before adding it to the mixture obtained in step S2 and mixing evenly. S4. Cool down to 40℃, add curing agent and penetrant in sequence, continue to react for 2~3 hours, and after degassing, obtain low viscosity high penetration epoxy resin adhesive. Example

[0028] A low-viscosity, high-penetration epoxy resin adhesive comprises the following components in parts by weight: 50 kg of bisphenol F type epoxy resin, 18 kg of bis((3,4-epoxycyclohexyl)methyl)adipate, 30 kg of curing agent, 10 kg of reactive diluent, 5 kg of toughening agent, 1 kg of nano silica, 1 kg of siloxane coupling agent, 2 kg of accelerator, and 0 kg of penetrant.

[0029] The curing agent is a polyetheramine modified epoxy curing agent (Suzhou Hengsite C-16 type).

[0030] The active diluent is an ionic liquid diluent system, which is a mixture of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and butyl glycidyl ether in a mass ratio of 1:1.

[0031] The toughening agent is a carboxyl-terminated liquid nitrile rubber.

[0032] The accelerator is 2-ethyl-4-methylimidazole.

[0033] The siloxane coupling agent is γ-aminopropyltriethoxysilane.

[0034] The preparation method of the epoxy resin adhesive described above is the same as in Example 1. Example

[0035] A low-viscosity, high-penetration epoxy resin adhesive comprises the following components in parts by weight: 50 kg of bisphenol F type epoxy resin, 18 kg of bis((3,4-epoxycyclohexyl)methyl)adipate, 30 kg of curing agent, 10 kg of reactive diluent, 5 kg of toughening agent, 1 kg of nano silica, 1 kg of siloxane coupling agent, 2 kg of accelerator, and 0 kg of penetrant.

[0036] The curing agent is a polyetheramine modified epoxy curing agent (Suzhou Hengsite C-16 type).

[0037] The active diluent is 1,4-cyclohexanediethanol diglycidyl ether.

[0038] The toughening agent is hyperbranched polylysine.

[0039] The accelerator is 2-ethyl-4-methylimidazole.

[0040] The siloxane coupling agent is γ-aminopropyltriethoxysilane.

[0041] The preparation method of the epoxy resin adhesive described above is the same as in Example 1. Example

[0042] A low-viscosity, high-penetration epoxy resin adhesive comprises the following components in parts by weight: 50 kg of bisphenol F type epoxy resin, 18 kg of bis((3,4-epoxycyclohexyl)methyl)adipate, 30 kg of curing agent, 10 kg of reactive diluent, 5 kg of toughening agent, 1 kg of nano silica, 1 kg of siloxane coupling agent, 2 kg of accelerator, and 0.5 kg of penetrant.

[0043] The curing agent is a polyetheramine modified epoxy curing agent (Suzhou Hengsite C-16 type).

[0044] The active diluent is 1,4-cyclohexanediethanol diglycidyl ether.

[0045] The toughening agent is hyperbranched polylysine.

[0046] The accelerator is 2-ethyl-4-methylimidazole.

[0047] The siloxane coupling agent is γ-aminopropyltriethoxysilane.

[0048] The preparation method of the epoxy resin adhesive described above is the same as in Example 1.

[0049] Comparative Example 1 The accelerator and nano-silica of Comparative Example 1 are added in step S2, and step S3 is omitted. The rest is the same as in Example 1, and will not be repeated.

[0050] Comparative Example 2 In Example 1, the bisphenol F epoxy resin was replaced with bisphenol A epoxy resin, and the rest was the same as in Example 1, so it will not be repeated here.

[0051] The performance of the low-viscosity, high-penetration epoxy resin adhesives prepared in the above examples and comparative examples was tested, and the results are shown in Table 1. The epoxy resin adhesives prepared above can be used in the construction and electronics fields.

[0052] Table 1 Measurement Results Viscosity, mPa·s (25℃) 794 762 788 773 822 850 Tensile strength, MPa 65 67 69 65 55 64 Volume resistivity, Ω·cm <![CDATA[4.8×10¹ 5 ]]> <![CDATA[4.7×10¹ 5 ]]> <![CDATA[4.7×10¹ 5 ]]> <![CDATA[4.8×10¹ 5 ]]> <![CDATA[4.4×10¹ 5 ]]> <![CDATA[4.6×10¹ 5 ]]> Penetration depth, mm / 10min 6.2 6.1 6.2 7.2 4.8 5.7 The data in the table above shows that the low-viscosity, high-penetration epoxy resin adhesives prepared in Examples 1-4 have low viscosity, high tensile strength, and high penetration depth, which can meet the needs of various applications. A comparison of the data from Examples 1, 2, 3, and 4 indicates that the ionic liquid diluent system can improve the tensile strength of the product and reduce its viscosity to a certain extent. Hyperbranched polylysine as the toughening agent has a better toughening effect, and the addition of a penetrant increases the product's penetration depth. The data from Comparative Example 1 shows that the preparation method has a significant impact on the product's performance. The bisphenol F epoxy resin from Comparative Example 2 has a lower viscosity and better performance than the bisphenol A epoxy resin.

Claims

1. A method for preparing a low-viscosity, high-penetration epoxy resin adhesive, characterized in that, The preparation steps include the following: S1. Bisphenol F type epoxy resin, bis((3,4-epoxycyclohexyl)methyl) adipate, and reactive diluent are mixed and dehydrated at 50°C; S2. Add toughening agent and siloxane coupling agent to the mixture obtained in step S1, and ultrasonically disperse at 60°C for 20 min to obtain a mixture; S3. Heat the accelerator to 60°C to melt it, then add nano-silica and stir for 1 hour before adding it to the mixture obtained in step S2 and mixing evenly. S4. Cool down to 40℃, add curing agent and penetrant in sequence, continue to react for 2~3 hours, and after degassing, obtain low viscosity high penetration epoxy resin adhesive; The high-penetration epoxy resin adhesive comprises the following components in parts by weight: 45-55 parts of bisphenol F type epoxy resin, 15-20 parts of bis((3,4-epoxycyclohexyl)methyl)adipate, 25-35 parts of curing agent, 5-15 parts of reactive diluent, 3-8 parts of toughening agent, 0.5-1 part of nano silica, 0.5-2 parts of siloxane coupling agent, 1-2 parts of accelerator, and 0-0.5 parts of penetrant.

2. The method for preparing epoxy resin adhesive according to claim 1, characterized in that, The curing agent is a polyetheramine-modified epoxy curing agent.

3. The method for preparing epoxy resin adhesive according to claim 1, characterized in that, The active diluent is 1,4-cyclohexanediethanol diglycidyl ether or an ionic liquid diluent system, wherein the ionic liquid diluent system is a mixture of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and butyl glycidyl ether in a mass ratio of 1:

1.

4. The method for preparing epoxy resin adhesive according to claim 1, characterized in that, The toughening agent is at least one of carboxyl-terminated liquid butadiene nitrile rubber and hyperbranched polylysine.

5. The method for preparing epoxy resin adhesive according to claim 1, characterized in that, The penetrant is isopropanol.

6. The method for preparing epoxy resin adhesive according to claim 1, characterized in that, The accelerator is 2-ethyl-4-methylimidazole.

7. The method for preparing epoxy resin adhesive according to claim 1, characterized in that, The siloxane coupling agent is γ-aminopropyltriethoxysilane.

8. The application of an epoxy resin adhesive obtained by any one of claims 1 to 7 in the fields of construction and electronics.