Chip-level underfill epoxy curing agent and preparation method thereof

Abstract

The present application relates to a kind of chip level underfill epoxy curing agent and its preparation method, belong to epoxy glue technical field, it is prepared using including the following weight parts of raw materials: dimer acid 60-80 parts;Polyamine compound 10-30 parts;Bie epoxy compound 10-40 parts;The polyamine compound has 4 and above active hydrogen.The preparation method of the chip level underfill epoxy curing agent of the present application mainly includes the following steps: step (1), in the presence of catalyst, dimer acid and bie epoxy compound are ring-opening reaction, obtain intermediate product;Step (2), the intermediate product obtained in step (1) is end-capped with polyamine compound, and epoxy curing agent is prepared.The synthesis process of the present application is mild, is conducive to cost control, can effectively improve the cold and hot impact resistance and humidity resistance of epoxy glue.

Description

Technical Field

[0001] This invention relates to a chip-level underfill epoxy curing agent and its preparation method, belonging to the field of epoxy adhesive technology. Background Technology

[0002] Petrochemical resources are non-renewable resources. The limited availability of these resources, along with the energy consumption and environmental problems associated with their production, makes research on bio-based epoxy curing agents particularly noteworthy. Academic and industrial sectors are seeking to replace petroleum-based materials with natural bio-based raw materials to meet the environmental compatibility requirements of the epoxy resin industry and promote sustainable development. Extensive research has been conducted both domestically and internationally on the preparation of epoxy curing agents from bio-based raw materials. Due to their advantages such as low environmental impact, easy availability, low cost, and biodegradability, they have been widely used in low-temperature curing, heat resistance, and corrosion resistance applications.

[0003] With the miniaturization and increasing functionality of electronic devices, the demand for high-density packaged semiconductor chips and other electronic components is rising. Flip chips have been widely used due to their smaller package size, narrower pitch, and high I / O density. Since flip chip mounting directly connects the semiconductor chip to the substrate, if the stress caused by the difference in thermal expansion coefficients between the silicon chip and the substrate cannot be absorbed, cracks will appear at the connection point, reducing the reliability of the connection between the semiconductor chip and the substrate. Therefore, the thermal shock resistance of epoxy adhesives is particularly important. Furthermore, underfill epoxy adhesives have high requirements for aging performance, and must not show degradation under high temperature and high humidity environments. This also places high demands on the epoxy adhesive's resistance to damp heat. As a crucial component of epoxy adhesives, the performance of the epoxy curing agent affects the epoxy adhesive's resistance to damp heat and thermal shock; therefore, higher performance requirements are needed for epoxy curing agents. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention provides a chip-level underfill epoxy curing agent and its preparation method. This invention uses bio-based dimer acid as the main raw material, and enhances the flexibility of the curing agent through its 18 carbon chain segments, thereby improving its resistance to thermal shock. In addition to ensuring good thermal shock performance, another advantage of dimer acid is its good water resistance and temperature resistance, which can effectively improve the humid heat resistance of epoxy adhesives.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] One objective of this invention is to provide a chip-level underfill epoxy curing agent, which is prepared using raw materials comprising the following parts by weight:

[0007] 60-80 parts of dimer acid;

[0008] 10-30 parts of a polyamine compound, wherein the polyamine compound has 4 or more active hydrogen atoms;

[0009] 10-40 parts of biepoxide.

[0010] Based on the above technical solution, the present invention can also be improved as follows:

[0011] Furthermore, the polyamine compound includes 2,4-dimethyldiphenylamine and / or 2-dimethyldiphenylamine.

[0012] Furthermore, the biepoxide compound includes di(2-epoxypropyl) ether and / or ethylene glycol diglycidyl ether.

[0013] The second objective of this invention is to provide a method for preparing the aforementioned chip-level underfill epoxy curing agent, which mainly includes the following steps:

[0014] Step (1): In the presence of a catalyst, the dimer acid is subjected to a ring-opening reaction with the diepoxide to obtain an intermediate product;

[0015] Step (2): The intermediate product obtained in step (1) is subjected to a capping reaction with a polyamine compound to obtain an epoxy curing agent.

[0016] Furthermore, in step (1), based on the acid value of the dimer acid, according to n 羧基 ∶n 环氧基 Add materials in a ratio of 1:2 to 1:3.

[0017] Furthermore, in step (1), the dimer acid is a solution, the solvent is a 1,4-dioxane solution, and the mass fraction of the dimer acid is 60-80%.

[0018] Furthermore, the specific operation of step (1) is as follows:

[0019] A solution of 1,4-dioxane in dimer acid was added dropwise to a container containing a diepoxide compound and hexadecyltrimethylammonium chloride. After the addition was complete, the mixture was kept at 65℃~95℃ for 2~3 hours. After the reaction was completed, all the solvent was evaporated under reduced pressure to obtain the intermediate product modified with dimer acid.

[0020] Furthermore, the specific operation of step (2) is as follows:

[0021] The intermediate product obtained in step (1) is dissolved in ethanol to prepare an ethanol solution with a mass fraction of 60%-80%. The ethanol solution of the intermediate product is added dropwise to a container containing a polyamine compound at 30℃-60℃. After the addition is complete, the mixture is kept at 50℃-70℃ for 4h-8h. After the reaction is completed, the ethanol is evaporated under reduced pressure to obtain the chip-level bottom filler epoxy curing agent.

[0022] Furthermore, in step (2), based on the epoxy value of the intermediate product, according to n 环氧基 ∶n 胺值 Add the ingredients in a ratio of 1:2 to 1:3.

[0023] The beneficial effects of this invention are as follows: This invention uses bio-based dimer acid as the main raw material. Dimer acid itself has very low carboxylic acid reactivity and cannot be used alone as a curing agent for base-filled epoxy resins. This invention, through a two-step polymer modification reaction, synthesizes an epoxy curing agent whose resin structure contains at least four amine groups that can react with epoxy groups, with more than four reactive groups on each molecular chain, which can improve the mechanical properties of the cured epoxy resin. Secondly, the structure of this invention can significantly improve the compatibility between the curing agent and epoxy resin, allowing it to be well-compatible with various epoxy resins without microscopic phase separation. Furthermore, the 18 carbon units of the dimer acid effectively improve the flexibility of the curing agent, thereby enhancing its resistance to thermal shock. In addition to ensuring good thermal shock performance, another advantage of dimer acid is its good water resistance and temperature resistance, which can significantly improve the adhesive's resistance to damp heat. Moreover, the synthesis process of this invention is mild, which is beneficial for cost control. Detailed Implementation

[0024] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0025] Example 1

[0026] 0.1 mol of dimer acid was dissolved in 1,4-dioxane to prepare a 60% (w / w) solution of dimer acid. The 1,4-dioxane solution of dimer acid was added dropwise to a four-necked flask containing 0.2 mol of di(2-epoxypropyl) ether and hexadecyltrimethylammonium chloride. After the addition was complete, the mixture was kept at 65°C for 3 hours. After the reaction was complete, all low-boiling-point substances were distilled off under reduced pressure to obtain intermediate 1, modified with dimer acid.

[0027] Dissolve 100g of intermediate 1 in ethanol to prepare a 60% (w / w) ethanol solution. Based on the epoxy value of intermediate 1, proceed according to n. 环氧基 ∶n 胺值 The ratio of intermediate 1 to 2 was 1:2. The ethanol solution of intermediate 1 was added dropwise to a four-necked flask containing 2,4-dimethyldiphenylamine and 2-dimethyldiphenylamine at 30°C. After the addition was complete, the mixture was kept at 50°C for 4 hours. After the reaction was complete, the ethanol was evaporated under reduced pressure to obtain chip-level bottom filler epoxy curing agent 1.

[0028] Example 2

[0029] 0.1 mol of dimer acid was dissolved in 1,4-dioxane to prepare a 70% (w / w) solution of dimer acid. The 1,4-dioxane solution of dimer acid was added dropwise to a four-necked flask containing 0.3 mol of ethylene glycol diglycidyl ether and hexadecyltrimethylammonium chloride. After the addition was complete, the mixture was kept at 85°C for 3 hours. After the reaction was completed, all low-boiling-point substances were distilled off under reduced pressure to obtain intermediate 1, modified with dimer acid.

[0030] Dissolve 100g of intermediate 1 in ethanol to prepare a 60% (w / w) ethanol solution. Based on the epoxy value of intermediate 1, proceed according to n... 环氧基 ∶n 胺值 The ratio of intermediate 1 to ethanol was 1:3. The ethanol solution of intermediate 1 was added dropwise to a four-necked flask containing 2,4-dimethyldiphenylamine at 30°C. After the addition was complete, the mixture was kept at 70°C for 8 hours. After the reaction was complete, the ethanol was evaporated under reduced pressure to obtain chip-level bottom-filling epoxy curing agent 2.

[0031] Example 3

[0032] 0.1 mol of dimer acid was dissolved in 1,4-dioxane to prepare a solution with a mass fraction of 80% dimer acid. The 1,4-dioxane solution of dimer acid was added dropwise to a four-necked flask containing 0.25 mol of di(2-epoxypropyl) ether and hexadecyltrimethylammonium chloride. After the addition was complete, the mixture was kept at 80 °C for 3 hours. After the reaction was completed, all low-boiling-point substances were distilled off under reduced pressure to obtain intermediate 1, modified with dimer acid.

[0033] Dissolve 100g of intermediate 1 in ethanol to prepare a 60% (w / w) ethanol solution. Based on the epoxy value of intermediate 1, proceed according to n... 环氧 Base: n 胺值 The ratio of the intermediate to ethanol was 1:2.5. The ethanol solution was added dropwise at 50°C to a four-necked flask containing 2,4-dimethyldiphenylamine and 2-dimethyldiphenylamine. After the addition was complete, the mixture was kept at 70°C for 6 hours. After the reaction was complete, the ethanol was evaporated under reduced pressure to obtain the chip-level bottom-filling epoxy curing agent 3.

[0034] Example 4

[0035] 0.1 mol of dimer acid was dissolved in 1,4-dioxane to prepare a 60% (w / w) solution of dimer acid. The 1,4-dioxane solution of dimer acid was added dropwise to a four-necked flask containing 0.25 mol of ethylene glycol diglycidyl ether and hexadecyltrimethylammonium chloride. After the addition was complete, the mixture was kept at 75°C for 3 hours. After the reaction was complete, all the solvent was evaporated under reduced pressure to obtain intermediate 1, modified with dimer acid.

[0036] Dissolve 100g of intermediate 1 in ethanol to prepare a 60% (w / w) ethanol solution. Based on the epoxy value of intermediate 1, proceed according to n... 环氧基∶n 胺值 The ratio of intermediate 1 to 2.5 was 1:2.5. The ethanol solution of intermediate 1 was added dropwise to a four-necked flask containing 2-dimethyldiphenylamine at 30°C. After the addition was complete, the mixture was kept at 60°C for 6 hours. After the reaction was complete, the ethanol was evaporated under reduced pressure to obtain chip-level bottom-filling epoxy curing agent 4.

[0037] Four epoxy curing agents 1-4 were obtained using the above four examples. They were prepared into epoxy adhesives with epoxy resin E-51 and curing accelerator, and their performance was tested. Comparative Examples 1-2 were prepared into epoxy adhesives using 2,4-dimethyldiphenylamine and 2-dimethyldiphenylamine as curing agents, respectively, and their thermal shock performance and aging performance were tested using the double 85 test.

[0038] Viscosity test: The viscosity of the freshly prepared evaluation sample was measured using a TA rheometer at 25°C and 60 rpm.

[0039] Hardness test: The Shore D hardness tester was used to measure the hardness at 25°C.

[0040] Tensile strength test: Refer to national standard GB / T 528-1998. Prepare dumbbell-shaped samples and test them using a tensile tester.

[0041] Thermal shock: Temperature range: -60℃~140℃, 1 hour per cycle; Judgment criteria: Apply a certain amount of glue to the PCB board, place a 5mm*5mm glass sheet on the glue, cure at 120℃ for 2 hours, then at 150℃ for 3 hours, test its initial thrust, and test its thrust again after thermal shock to see the attenuation.

[0042] Double 85 aging test: Sample preparation and judgment criteria refer to thermal shock.

[0043] The results of the above tests are shown in Table 1.

[0044] Table 1 Performance Test Data Results

[0045]

[0046] Based on the comparative data above, the elongation at break of Examples 1-4 is significantly improved compared to the control group, which greatly improves the toughness of the adhesive. The attenuation of thermal shock and double 85 aging is less than 5%, while the attenuation of the control group is very serious. From the above data, it can be concluded that the curing agent synthesized in this invention has excellent resistance to thermal shock and double 85 aging.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A chip-level underfill epoxy curing agent, characterized in that, It is prepared by the following method: The method includes the following steps: (1) Dissolve 0.1 mol of dimer acid in 1,4-dioxane to prepare a solution with a mass fraction of 70% dimer acid, and obtain a dimer acid solution; The dimer acid solution was added dropwise to a reaction vessel containing 0.3 mol of ethylene glycol diglycidyl ether and the catalyst hexadecyltrimethylammonium chloride. After the addition was complete, the reaction was kept at 85°C for 3 hours. After the reaction was completed, all the solvent was evaporated under reduced pressure to obtain the dimer acid-modified epoxy intermediate. (2) Dissolve 100 g of the dimer acid modified epoxy intermediate obtained in step (1) in ethanol to prepare an ethanol solution with a mass fraction of 60% to obtain the intermediate solution. Based on the epoxy value of the dimer acid-modified epoxy intermediate, according to the molar ratio n of epoxy groups to amine groups... 环氧基 :n 胺基 The intermediate solution was added dropwise to a reaction vessel containing 2,4-dimethyldiphenylamine at a ratio of 1:3 and 30°C. After the addition was complete, the reaction was maintained at 70°C for 8 hours. After the reaction was completed, the ethanol was evaporated under reduced pressure to obtain the chip-level bottom filler epoxy curing agent.

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