Preparation method of modified FEP resin for electronic packaging

Abstract

The invention discloses a preparation method of modified FEP resin for electronic packaging, and relates to the field of fluorine-containing polymer preparation. According to the method, a third modified monomer containing hydroxyl, trimethylsilyl and pyridyl is introduced, an FEP molecular chain is embedded in the polymerization process, and after the reaction is finished, washing, drying and granulation are performed to obtain the modified resin. The resin provided by the invention has the advantages of low dielectric constant, low water absorption rate, excellent interface bonding force and machinability, and is suitable for the field of electronic packaging.

Description

Technical Field

[0001] This invention relates to the field of fluoropolymer preparation, and in particular to a method for preparing a modified FEP resin for electronic packaging. Background Technology

[0002] Fluorinated ethylene-propylene copolymer (FEP) is a melt-processable perfluoroolefin resin copolymerized from tetrafluoroethylene (TFE) and hexafluoropropylene (HFP). With a melting point of approximately 260°C, it can be used for injection molding and extrusion. It possesses excellent properties similar to PTFE, such as extremely low surface energy, extremely high chemical inertness, and thermal stability (maximum operating temperature approximately 204°C). Its low dielectric constant (≈2.1 @1MHz), low dissipation factor (≈0.0007), and low water absorption make it widely used in high-frequency electronic packaging and corrosion-resistant environments.

[0003] However, due to its low surface energy and inert structure, FEP exhibits poor adhesion to common substrates such as metals and ceramics, and is considered one of the "difficult-to-adhere materials." While attempting to directly mechanically roughen the substrate (e.g., sandblasting) can improve adhesion, it easily disrupts surface smoothness, leading to increased dielectric loss, degraded signal transmission, and other problems in electronic applications. Traditional chemical modification or coating methods often suffer from performance degradation and processing complexity.

[0004] In high-density electronic packaging and multilayer interconnect boards for chips, the requirements for the adhesion strength between resin and metal substrates such as copper and aluminum are significantly increased. For example, in chip applications with micron-level linewidths and spatial traces, insufficient substrate adhesion strength will lead to reliability issues such as cracking and delamination, and simple coating or physical roughening methods are insufficient to meet the requirements of high-performance integration. In addition, regarding metal-polymer interface enhancement, although low-temperature plasma, chemical substrates, and silane coupling technology can increase surface energy or introduce active functional groups, they require complex processes, costly vacuum / plasma equipment, and are difficult to scale up.

[0005] Current modification techniques focus on surface treatment or the addition of incompatible fillers, while research on the molecular structure regulation of FEP itself is limited, and there is a lack of systematic molecular-level design methods to achieve a balance between adhesion, thermal stability, and chemical stability. Considering the diverse application requirements such as electronic packaging, corrosion-resistant coatings, and high-temperature composite materials, a method that can enhance interfacial adhesion while preserving the bulk properties of FEP is urgently needed. Summary of the Invention

[0006] Based on the problems raised in the background art, this invention proposes a method for preparing modified FEP resin for electronic packaging. By introducing a third monomer (vinyltrimethoxysilane, VTMS) into the main chain structure of the FEP copolymer system, molecular-level "structural regulation" is achieved, altering its regularity and functional group structure, improving interfacial adhesion, and maintaining its inherent excellent properties. This strategy avoids damage to the surface structure and eliminates the need for additional surface treatment processes, enabling FEP to possess "endogenous modification" potential in terms of functional expansion, making it suitable for industrial-scale mass production.

[0007] The technical solution is as follows: A method for preparing a modified FEP resin for electronic packaging, characterized by comprising the following steps: a. Add 6000-8000 parts of deionized water, 0-2 parts of chain transfer agent, 8-16 parts of perfluoropolyether ammonium carboxylate emulsifier and 32-48 parts of third modified monomer to a vertical polymerization reactor, start stirring in the polymerization reactor, and evacuate to O2 ≤30ppm; b. Introduce the initial mixed monomers TFE and HFP until the pressure inside the polymerization reactor reaches 0.12-0.18 MPa; c. Heat the polymerization reactor to 45-55°C to stabilize the pressure inside the reactor at 1.75-1.85 MPa; d. After adding 6-12 parts of initiator at once, add 2-4 parts in 4-8 batches during the reaction. When the monomer pressure reaches 2.0 MPa, continue to add the mixed monomer TFE:HFP until the cumulative pressure drop is 0.24 MPa, and the reaction ends. e. After the reaction is complete, the polymerization reactor is depressurized and cooled. The reaction slurry is then washed, dried, and granulated to obtain the FEP resin.

[0008] In some embodiments of the present invention, the chain transfer agent is selected from methanol, methyl formate, tert-butyl acetate, diethyl malonate, and carbon tetrachloride, and any one of them is selected.

[0009] In some embodiments of the present invention, the preparation method of the third modified monomer is as follows: Step 1: Controlled esterification reaction Procedure: In a nitrogen-protected three-necked flask, add 28-56 parts of perfluoro(4-methyl-2-pentanoic acid) (CAS: 103229-89-6), 6-12 parts of trans-3-(trimethylsilyl)allyl alcohol (CAS: 59376-64-6), 7-14 parts of 2-(4-pyridine)allyl alcohol (CAS: 57360-16-4), and 1000-1300 parts of anhydrous THF. After stirring until homogeneous, cool to 0-5℃. Slowly add 52-65 parts of a THF solution of dicyclohexylcarbodiimide (20wt%), and react at 5-15℃ for 3-4 hours. Step 2: Purification Step Filtration: After the reaction is complete, filter to remove the byproduct dicyclohexylurea (DCU). Neutralization and washing: Slowly add 5% sodium bicarbonate solution to the filtrate until the pH reaches 7.0-7.2, transfer to a separatory funnel, collect the organic phase; wash with deionized water 3-4 times until neutral; Dry distillation: The organic phase is dried with anhydrous sodium sulfate for 40-60 minutes. After filtration, the filtrate is distilled under reduced pressure at a vacuum of 0.08-0.09 MPa. The fraction at 85-95℃ is collected to obtain the third monomer containing carbon-carbon double bonds.

[0010] In some embodiments of the present invention, the stirring speed of the polymerization reactor is 300-450 rpm.

[0011] In some embodiments of the present invention, the initial mixed monomers TFE and HFP have a molar ratio of 15-45:55-85.

[0012] In some embodiments of the present invention, the chain transfer agent is selected from any one of methanol, carbon tetrachloride, and diethyl malonate.

[0013] In some embodiments of the present invention, the initiator is selected from ammonium persulfate or potassium persulfate solution, and the solution concentration is 0.5-5 wt%.

[0014] In some embodiments of the present invention, the molar ratio of the added mixed monomers TFE and HFP is 75-96:4-25.

[0015] Reaction mechanism Perfluoro(4-methyl-2-pentanoic acid) (RCOOH) undergoes esterification with trans-3-(trimethylsilyl)allyl alcohol (HO-R1) and 2-(4-pyridine)allyl alcohol (HO-R2) in the presence of dicyclohexylcarbodiimide (DCC): RCOOH + HO-R1 + DCC → RCOO-R1 + DCU (byproduct) RCOOH + HO-R2 + DCC → RCOO-R2 + DCU (byproduct) (R is a perfluoroalkyl group, R1 contains an allyl double bond and a trimethylsilyl group, and R2 contains an allyl double bond and a pyridyl group.) DCC activates the carboxyl group to form a highly active O-acyl isourea intermediate; The hydroxyl group of allyl alcohol nucleophilically attacks the intermediate, forming an ester bond and generating DCU (a solid that is easily separated). The allyl double bond remains intact because of the stability of the π bond and steric hindrance (silicyl and pyridyl groups) and does not participate in the reaction.

[0016] Compared with the prior art, the present invention has the following advantages: 1) Significantly improved interfacial compatibility and adhesion performance: Hydroxyl groups form hydrogen bonds with the substrate surface, and pyridyl groups coordinate with metals, which increases the adhesion strength of modified FEP to polar substrates such as metals and ceramics by several times, solving the problem of weak interfacial bonding of traditional FEP.

[0017] 2) Enhanced resistance to damp heat and thermal stability: The hydrophobicity of the trimethylsilyl group reduces the water absorption rate (<0.01%), and the aromatic structure of the pyridyl group increases the thermal decomposition temperature, so that the material remains stable in a damp heat environment of 85℃ / 85% RH, and the long-term service temperature is widened to 200℃-260℃.

[0018] 3) Low dielectric and water resistance optimization: The synergy of perfluoroalkyl and silicon groups makes the dielectric constant of modified FEP ≤2.0 and the water absorption rate ≤0.008%, which is suitable for high-frequency signal transmission; Interface and processability balance: Pyridine groups improve the adhesion strength to the substrate, the retained double bonds achieve uniform copolymerization, and ester groups ensure melt flowability, which is suitable for complex encapsulation processes. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1

[0020] Raw material formula: Deionized water: 6000g Chain transfer agent (methanol): 0.5g Emulsifier (4wt% perfluoropolyether ammonium carboxylate solution): 8g Third modified monomer: 32g Initiator (0.5wt% ammonium persulfate solution): 6g (added all at once) + 2g x 4 times (added again). Preparation steps: 1. Premixing and deoxygenation: Add the above raw materials to a vertical polymerization reactor, stir at 300 rpm, and evacuate to O2 ≤ 30 ppm.

[0021] 2. Initial ventilation: Introduce a mixed monomer of TFE:HFP=15:85 (molar ratio) until the pressure reaches 0.12MPa.

[0022] 3. Heating and pressure stabilization: Heat to 45°C and maintain pressure at 1.75 MPa.

[0023] 4. Triggering and Feeding: Add 6g of initiator at once, and add 2g every 30 minutes during the reaction, for a total of 4 times.

[0024] When the pressure reaches 2.0 MPa, add a monomer with a TFE:HFP ratio of 75:25 (molar ratio) and continue the reaction until the cumulative pressure drop reaches 0.24 MPa.

[0025] 5. Post-processing: depressurize and cool down, wash the slurry, dry at 100°C, and granulate.

[0026] Synthesis of the third modified monomer: Step 1: Controlled esterification reaction Procedure: In a nitrogen-protected three-necked flask, add 28g of perfluoro(4-methyl-2-valeric acid) (CAS: 103229-89-6), 6g of trans-3-(trimethylsilyl)allyl alcohol (CAS: 59376-64-6), 7g of 2-(4-pyridine)allyl alcohol (CAS: 57360-16-4), and 1000g of anhydrous THF. After stirring until homogeneous, cool to 0℃. Slowly add 52g of a THF solution of dicyclohexylcarbodiimide (20wt%), and react at 5℃ for 3 hours.

[0027] Step 2: Purification Step Filtration: After the reaction is complete, filter to remove the byproduct dicyclohexylurea (DCU). Neutralization and washing: Slowly add 5% sodium bicarbonate solution to the filtrate until pH=7.0, transfer to a separatory funnel, collect the organic phase; wash 3 times with deionized water until neutral; Dry distillation: The organic phase was dried with anhydrous sodium sulfate for 40 minutes. After filtration, the filtrate was distilled under reduced pressure at a vacuum of 0.08 MPa. The fraction at 85°C was collected to obtain the third monomer containing carbon-carbon double bonds. Example 2

[0028] Raw material formula: Deionized water: 6500g Chain transfer agent (carbon tetrachloride): 0.5g Emulsifier (5wt% perfluoropolyether ammonium carboxylate solution): 10g Third modified monomer: 36g Initiator (2wt% potassium persulfate solution): 8g (added all at once) + 2.5g × 5 times (added as needed) Preparation steps: 1. Premixing and deoxygenation: Stir at 350 rpm and evacuate to O2 ≤ 30 ppm.

[0029] 2. Initial ventilation: TFE:HFP = 25:75 (molar ratio), pressure 0.14 MPa.

[0030] 3. Heating and pressure stabilization: Heating to 48°C and pressure 1.78MPa.

[0031] 4. Triggering and Feeding: Add 8g of initiator at once, and add 2.5g every 40 minutes for a total of 5 times.

[0032] The reaction was terminated by adding monomers TFE:HFP = 80:20 and reducing the pressure drop to 0.24 MPa.

[0033] 5. Post-processing: Same as in Example 1.

[0034] Synthesis of the third modified monomer: Step 1: Controlled esterification reaction Procedure: In a nitrogen-protected three-necked flask, add 35g of perfluoro(4-methyl-2-valeric acid) (CAS: 103229-89-6), 8g of trans-3-(trimethylsilyl)allyl alcohol (CAS: 59376-64-6), 9g of 2-(4-pyridine)allyl alcohol (CAS: 57360-16-4), and 1100g of anhydrous THF. After stirring until homogeneous, cool to 2°C. Slowly add 56g of a THF solution of dicyclohexylcarbodiimide (20wt%), and react at 8°C for 3.2 hours.

[0035] Step 2: Purification Step Filtration: After the reaction is complete, filter to remove the byproduct dicyclohexylurea (DCU). Neutralization and washing: Slowly add 5% sodium bicarbonate solution to the filtrate until pH=7.1, transfer to a separatory funnel, collect the organic phase; wash 3 times with deionized water until neutral; Dry distillation: The organic phase was dried with anhydrous sodium sulfate for 45 minutes. After filtration, the filtrate was distilled under reduced pressure at a vacuum of 0.082 MPa. The fraction at 88℃ was collected to obtain the third monomer containing carbon-carbon double bonds. Example 3

[0036] Raw material formula: Deionized water: 7000g Chain transfer agent (diethyl malonate): 1.5g Emulsifier (6wt% perfluoropolyether ammonium carboxylate solution): 12g Third modified monomer: 42g Initiator (3.5wt% ammonium persulfate solution): 10g (added all at once) + 3g x 6 times (added again). Preparation steps: 1. Premixing and deoxygenation: Stir at 400 rpm and evacuate to O2 ≤ 30 ppm.

[0037] 2. Initial ventilation: TFE:HFP=35:65 (molar ratio), pressure 0.16MPa.

[0038] 3. Heating and pressure stabilization: Heating to 52°C and pressure to 1.82MPa.

[0039] 4. Triggering and Feeding: Add 10g of initiator at once, and add 3g every 50 minutes for a total of 6 times.

[0040] The reaction was terminated by adding monomers TFE:HFP = 90:10 and reducing the pressure drop to 0.24 MPa.

[0041] 5. Post-processing: Same as in Example 1.

[0042] Synthesis of the third modified monomer: Step 1: Controlled esterification reaction Procedure: In a nitrogen-protected three-necked flask, add 45g of perfluoro(4-methyl-2-valeric acid) (CAS: 103229-89-6), 10g of trans-3-(trimethylsilyl)allyl alcohol (CAS: 59376-64-6), 12g of 2-(4-pyridine)allyl alcohol (CAS: 57360-16-4), and 1200g of anhydrous THF. After stirring until homogeneous, cool to 4°C. Slowly add 61g of a THF solution of dicyclohexylcarbodiimide (20wt%), and react at 12°C for 3.6 hours.

[0043] Step 2: Purification Step Filtration: After the reaction is complete, filter to remove the byproduct dicyclohexylurea (DCU). Neutralization and washing: Slowly add 5% sodium bicarbonate solution to the filtrate until pH=7.1, transfer to a separatory funnel, collect the organic phase; wash 4 times with deionized water until neutral; Dry distillation: The organic phase was dried with anhydrous sodium sulfate for 55 minutes. After filtration, the filtrate was distilled under reduced pressure at a vacuum of 0.086 MPa. The fraction at 92℃ was collected to obtain the third monomer containing carbon-carbon double bonds. Example 4

[0044] Raw material formula: Deionized water: 8000g Chain transfer agent (methanol): 2g Emulsifier (8wt% perfluoropolyether ammonium carboxylate solution): 16g Third modified monomer: 48g Initiator (5wt% potassium persulfate solution): 12g (added all at once) + 4g x 8 times (added again). Preparation steps: 1. Premixing and deoxygenation: Stir at 450 rpm and evacuate to O2 ≤ 30 ppm.

[0045] 2. Initial ventilation: TFE:HFP = 45:55 (molar ratio), pressure 0.18 MPa.

[0046] 3. Heating and pressure stabilization: Heating to 55°C and pressure to 1.85MPa.

[0047] 4. Triggering and Feeding: Add 12g of initiator at once, and add 4g every 60 minutes for a total of 8 times.

[0048] The reaction was terminated by adding monomers TFE:HFP = 96:4 and reducing the pressure drop to 0.24 MPa.

[0049] 5. Post-processing: Same as in Example 1.

[0050] Synthesis of the third modified monomer: Step 1: Controlled esterification reaction Procedure: In a nitrogen-protected three-necked flask, add 56g of perfluoro(4-methyl-2-valeric acid) (CAS: 103229-89-6), 12g of trans-3-(trimethylsilyl)allyl alcohol (CAS: 59376-64-6), 14g of 2-(4-pyridine)allyl alcohol (CAS: 57360-16-4), and 1300g of anhydrous THF. After stirring evenly, cool to 5°C. Slowly add 65g of a THF solution of dicyclohexylcarbodiimide (20wt%), and react at 15°C for 4 hours.

[0051] Step 2: Purification Step Filtration: After the reaction is complete, filter to remove the byproduct dicyclohexylurea (DCU). Neutralization and washing: Slowly add 5% sodium bicarbonate solution to the filtrate until pH=7.2, transfer to a separatory funnel, collect the organic phase; wash 4 times with deionized water until neutral; Drying and distillation: The organic phase was dried with anhydrous sodium sulfate for 60 minutes. After filtration, the filtrate was distilled under reduced pressure at a vacuum of 0.09 MPa. The fraction at 95°C was collected to obtain the third monomer containing carbon-carbon double bonds.

[0052] Comparative Example 1 Raw material formula: Deionized water: 6000g Chain transfer agent (methanol): 0.5g Emulsifier (4wt% perfluoropolyether ammonium carboxylate solution): 8g Initiator (0.5wt% ammonium persulfate solution): 6g (added all at once) + 2g x 4 times (added again). Preparation steps: 1. Premixing and deoxygenation: Add the above raw materials to a vertical polymerization reactor, stir at 300 rpm, and evacuate to O2 ≤ 30 ppm.

[0053] 2. Initial ventilation: Introduce a mixed monomer of TFE:HFP=15:85 (molar ratio) until the pressure reaches 0.12MPa.

[0054] 3. Heating and pressure stabilization: Heat to 45°C and maintain pressure at 1.75 MPa.

[0055] 4. Triggering and Feeding: Add 6g of initiator at once, and add 2g every 30 minutes during the reaction, for a total of 4 times.

[0056] When the pressure reaches 2.0 MPa, add a monomer with a TFE:HFP ratio of 75:25 (molar ratio) and continue the reaction until the cumulative pressure drop reaches 0.24 MPa.

[0057] 5. Post-processing: depressurize and cool down, wash the slurry, dry at 100°C, and granulate.

[0058] Purification: Neutralize to pH 6.5 with saturated NaHCO3, separate the liquid and wash with water 6 times, dry the organic phase with anhydrous MgSO4 for 100 minutes, distill under reduced pressure at 0.08 MPa, and collect the fraction at 65°C.

[0059] Comparative Example 2 Raw material formula: Deionized water: 6000g Chain transfer agent (methanol): 0.5g Emulsifier (4wt% perfluoropolyether ammonium carboxylate solution): 8g Third modified monomer: 32g Initiator (0.5wt% ammonium persulfate solution): 6g (added all at once) + 2g x 4 times (added again). Preparation steps: 1. Premixing and deoxygenation: Add the above raw materials to a vertical polymerization reactor, stir at 300 rpm, and evacuate to O2 ≤ 30 ppm.

[0060] 2. Initial ventilation: Introduce a mixed monomer of TFE:HFP=15:85 (molar ratio) until the pressure reaches 0.12MPa.

[0061] 3. Heating and pressure stabilization: Heat to 45°C and maintain pressure at 1.75 MPa.

[0062] 4. Triggering and Feeding: Add 6g of initiator at once, and add 2g every 30 minutes during the reaction, for a total of 4 times.

[0063] When the pressure reaches 2.0 MPa, add a monomer with a TFE:HFP ratio of 75:25 (molar ratio) and continue the reaction until the cumulative pressure drop reaches 0.24 MPa.

[0064] 5. Post-processing: depressurize and cool down, wash the slurry, dry at 100°C, and granulate.

[0065] Synthesis of the third modified monomer: Step 1: Controlled esterification reaction Procedure: In a nitrogen-protected three-necked flask, add 28g of perfluoro(4-methyl-2-valeric acid) (CAS: 103229-89-6), 7g of 2-(4-pyridine)allyl alcohol (CAS: 57360-16-4), and 1000g of anhydrous THF. After stirring evenly, cool to 0℃. Slowly add 52g of a THF solution of dicyclohexylcarbodiimide (20wt%), and react at 5℃ for 3 hours.

[0066] Step 2: Purification Step Filtration: After the reaction is complete, filter to remove the byproduct dicyclohexylurea (DCU). Neutralization and washing: Slowly add 5% sodium bicarbonate solution to the filtrate until pH=7.0, transfer to a separatory funnel, collect the organic phase; wash 3 times with deionized water until neutral; Dry distillation: The organic phase was dried with anhydrous sodium sulfate for 40 minutes. After filtration, the filtrate was distilled under reduced pressure at a vacuum of 0.08 MPa. The fraction at 85°C was collected to obtain the third monomer containing carbon-carbon double bonds.

[0067] Comparative Example 3 Raw material formula: Deionized water: 6000g Chain transfer agent (methanol): 0.5g Emulsifier (4wt% perfluoropolyether ammonium carboxylate solution): 8g Third modified monomer: 32g Initiator (0.5wt% ammonium persulfate solution): 6g (added all at once) + 2g x 4 times (added again). Preparation steps: 1. Premixing and deoxygenation: Add the above raw materials to a vertical polymerization reactor, stir at 300 rpm, and evacuate to O2 ≤ 30 ppm.

[0068] 2. Initial ventilation: Introduce a mixed monomer of TFE:HFP=15:85 (molar ratio) until the pressure reaches 0.12MPa.

[0069] 3. Heating and pressure stabilization: Heat to 45°C and maintain pressure at 1.75 MPa.

[0070] 4. Triggering and Feeding: Add 6g of initiator at once, and add 2g every 30 minutes during the reaction, for a total of 4 times.

[0071] When the pressure reaches 2.0 MPa, add a monomer with a TFE:HFP ratio of 75:25 (molar ratio) and continue the reaction until the cumulative pressure drop reaches 0.24 MPa.

[0072] 5. Post-processing: depressurize and cool down, wash the slurry, dry at 100°C, and granulate.

[0073] Synthesis of the third modified monomer: Step 1: Controlled esterification reaction Procedure: In a nitrogen-protected three-necked flask, add 28g of perfluoro(4-methyl-2-valeric acid) (CAS: 103229-89-6), 6g of trans-3-(trimethylsilyl)allyl alcohol (CAS: 59376-64-6), and 1000g of anhydrous THF. After stirring until homogeneous, cool to 0℃. Slowly add 52g of a THF solution of dicyclohexylcarbodiimide (20wt%), and react at 5℃ for 3 hours.

[0074] Step 2: Purification Step Filtration: After the reaction is complete, filter to remove the byproduct dicyclohexylurea (DCU). Neutralization and washing: Slowly add 5% sodium bicarbonate solution to the filtrate until pH=7.0, transfer to a separatory funnel, collect the organic phase; wash 3 times with deionized water until neutral; Dry distillation: The organic phase was dried with anhydrous sodium sulfate for 40 minutes. After filtration, the filtrate was distilled under reduced pressure at a vacuum of 0.08 MPa. The fraction at 85°C was collected to obtain the third monomer containing carbon-carbon double bonds.

[0075] Test methods and test results: 1) Interfacial bond strength test: According to ASTM D4541-22, 20mm diameter dolly pins were glued to the surface of the cut sample. A portable pull-out tester was used to apply force vertically until the adhesive layer peeled off or broke, and the maximum adhesion strength was recorded. Experimental conditions: 23±2°C, humidity 50±5%, epoxy adhesive, curing time 24h, pull speed approximately 1mm / min.

[0076] Table 1 Results of interfacial bond strength test 2) Thermal stability test: Using a thermogravimetric analyzer (TA Q500), the temperature was increased to 800°C at 10°C / min in air atmosphere, and the relationship curve between sample weight and temperature was recorded. The 5% weight loss temperature (T5%) was taken as the thermal stability evaluation index.

[0077] Table 2 Thermal stability test results 3) Resistance to damp heat: Determine the change in mass of the sample after immersion at 85°C / 85% RH for 168 hours according to ASTM D570. Record the water absorption rate.

[0078] Table 3 Results of Damp Heat Resistance Test 4) Electrical performance testing: The dielectric constant and dissipation factor of the sample were determined at 1 kHz according to ASTM D150. The sample was of standard thickness (approximately 0.3 mm) and the measurements were performed using the two-plate method.

[0079] Table 4 Electrical performance test results The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a modified FEP resin for electronic packaging, characterized in that, Includes the following steps: a. Add 6000-8000 parts of deionized water, 0-2 parts of chain transfer agent, 8-16 parts of perfluoropolyether ammonium carboxylate emulsifier and 32-48 parts of third modified monomer to a vertical polymerization reactor, start stirring in the polymerization reactor, and evacuate to O2 ≤30ppm; b. Introduce the initial mixed monomers TFE and HFP until the pressure inside the polymerization reactor reaches 0.12-0.18 MPa; c. Heat the polymerization reactor to 45-55°C to stabilize the pressure inside the reactor at 1.75-1.85 MPa; d. After adding 6-12 parts of initiator at once, add 2-4 parts in 4-8 batches during the reaction. When the monomer pressure reaches 2.0 MPa, continue to add the mixed monomer TFE:HFP until the cumulative pressure drop is 0.24 MPa, and the reaction ends. e. After the reaction is complete, the polymerization reactor is depressurized and cooled. The reaction slurry is then washed, dried, and granulated to obtain the FEP resin.

2. The method for preparing a modified FEP resin for electronic packaging according to claim 1, characterized in that: The chain transfer agent is selected from methanol, methyl formate, tert-butyl acetate, diethyl malonate, and carbon tetrachloride, and may be chosen as one of them.

3. The method for preparing a modified FEP resin for electronic packaging according to claim 1, characterized in that: The preparation method of the third modified monomer is as follows: Step 1: Controlled esterification reaction Procedure: In a nitrogen-protected three-necked flask, add 28-56 parts of perfluoro(4-methyl-2-pentanoic acid), 6-12 parts of trans-3-(trimethylsilyl)allyl alcohol, 7-14 parts of 2-(4-pyridine)allyl alcohol, and 1000-1300 parts of anhydrous THF. After stirring until homogeneous, cool to 0-5℃. Slowly add 52-65 parts of a THF solution of dicyclohexylcarbodiimide (20wt%), and react at 5-15℃ for 3-4 hours. Step 2: Purification Step Filtration: After the reaction is complete, filter to remove the byproduct dicyclohexylurea; Neutralization and washing: Slowly add 5% sodium bicarbonate solution to the filtrate until the pH reaches 7.0-7.2, transfer to a separatory funnel, collect the organic phase; wash with deionized water 3-4 times until neutral; Dry distillation: The organic phase is dried with anhydrous sodium sulfate for 40-60 minutes. After filtration, the filtrate is distilled under reduced pressure at a vacuum of 0.08-0.09 MPa. The fraction at 85-95℃ is collected to obtain the third monomer containing carbon-carbon double bonds.

4. The method for preparing a modified FEP resin for electronic packaging according to claim 1, characterized in that: The stirring speed of the polymerization reactor is 300-450 rpm.

5. The method for preparing a modified FEP resin for electronic packaging according to claim 1, characterized in that: The initial mixed monomers TFE and HFP have a molar ratio of 15-45:55-85.

6. The method for preparing a modified FEP resin for electronic packaging according to claim 1, characterized in that: The chain transfer agent is selected from any one of methanol, carbon tetrachloride, and diethyl malonate.

7. The method for preparing a modified FEP resin for electronic packaging according to claim 1, characterized in that: The initiator is selected from ammonium persulfate or potassium persulfate solution, with a solution concentration of 0.5-5 wt%.

8. The method for preparing a modified FEP resin for electronic packaging according to claim 1, characterized in that: The molar ratio of the added mixed monomers TFE and HFP is 75-96:4-25.

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