Buffer film for packaging electronic component based on electromagnetic pulse welding
By preparing a buffer film based on electromagnetic pulse welding, and utilizing a combination of modified hydroxyl-terminated silicone oil and functionalized polyol chain extenders, the mechanical stress problem caused by electromagnetic pulse welding was solved, improving the mechanical properties and self-healing ability of electronic components and extending their service life.
Patent Information
- Application Number
- CN202511419421.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-30
- Publication Date
- 2025-12-05
AI Technical Summary
Existing electromagnetic pulse welding technology can easily cause mechanical stress to be transmitted to the fragile interior of electronic components, leading to irreversible damage such as lead wire breakage, solder joint failure, or chip cracks. In addition, high-frequency vibration and mechanical impact affect the service life.
A buffer film for packaging electronic components based on electromagnetic pulse welding was prepared by combining modified hydroxyl-terminated silicone oil, IPDI, polypropylene glycol and functionalized polyol chain extenders. The resulting buffer film has excellent mechanical properties and self-healing ability. The modified hydroxyl-terminated silicone oil absorbs energy, and the functionalized polyol chain extender forms a cross-linked network structure, achieving self-healing through dynamic reversible bonds.
It improves the mechanical properties and service life of electronic components, prevents material contamination, and enables self-repair after damage, thus extending service life.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer materials technology, specifically to a buffer film for packaging electronic components based on electromagnetic pulse welding. Background Technology
[0002] With the rapid development of electronic information technology, electronic components are evolving towards high performance, high density, miniaturization, and multifunctional integration. Their internal structures are becoming increasingly precise and fragile, making them extremely sensitive to mechanical stress, thermal stress, and external environmental interference. Electromagnetic pulse welding is a novel solid-state welding technology that utilizes instantaneous high-intensity electromagnetic fields to cause high-speed collisions in metal workpieces within microseconds, achieving metallurgical bonding through atomic diffusion and bonding.
[0003] When electromagnetic pulse welding technology is applied to electronic components, stress is directly transmitted to the fragile interior of the component when it is subjected to external impact or vibration, leading to irreversible damage such as lead wire breakage, solder joint failure, or chip cracking. Furthermore, high-frequency vibrations and mechanical shocks that occur during the transportation, installation, and long-term use of electronic components can still affect their lifespan.
[0004] Based on this, the present invention proposes a buffer film for packaging electronic components based on electromagnetic pulse welding. Applying this type of buffer film to electronic components can effectively protect the electronic components and extend their service life. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a buffer film for packaging electronic components based on electromagnetic pulse welding. The buffer film prepared by this invention has excellent mechanical properties, anti-fouling effect, and self-healing effect. When applied to electronic components, it can improve the service life of electronic components and effectively protect electronic components when using electromagnetic pulse welding technology.
[0006] A buffer film for packaging electronic components based on electromagnetic pulse welding, the method for preparing the buffer film includes the following steps:
[0007] Under nitrogen protection, modified hydroxyl-terminated silicone oil, IPDI, and polypropylene glycol (Mn=2000) were added to a flask and stirred until homogeneous. The mixture was heated to 65-70℃ and reacted for 1-2 hours. Then, a catalyst and DMPA were added, and the temperature was raised to 75-80℃, reacting for 2-3 hours. A functionalized polyol chain extender was added, and the temperature was raised to 80-85℃, reacting for 1-2 hours. The mixture was then allowed to cool naturally to 40℃, and triethylamine was added dropwise for neutralization. Finally, deionized water was added. The mixture is stirred and stirred until homogeneous, then poured into a clean polytetrafluoroethylene film-forming apparatus to dry into a film. The film is then placed in a vacuum drying oven at 50°C for 48 hours to obtain a buffer film for packaging electronic components based on electromagnetic pulse welding. This invention uses IPDI as the hard segment and polypropylene glycol and modified hydroxyl-terminated silicone oil as the soft segment to prepare the buffer film. Firstly, when the buffer film is subjected to impact, the modified hydroxyl-terminated silicone oil (containing a long siloxane backbone) can effectively absorb and disperse the consumed energy, thereby preventing cracking. The modified hydroxyl-terminated silicone oil is generated and extended to improve the mechanical properties of the material. Because it has low surface energy, it can migrate to the material surface during film formation, giving the buffer film low surface energy and achieving anti-fouling properties. Furthermore, the buffer film prepared by this invention contains dynamically reversible acylhydrazone bonds (found in the functionalized polyol chain extender), oxime urethane bonds (obtained by the reaction of the oxime group in the functionalized polyol chain extender with isocyanate), disulfide bonds (found in the modified hydroxyl-terminated silicone oil), and hydrogen bonds (formed between various polar groups; this strong hydrogen bond binding energy provides excellent mechanical properties to the polyurethane network; weaker hydrogen bonds preferentially bind during repair, promoting the repairability of the polyurethane film; and stronger hydrogen bonds enable the buffer film to not only have excellent mechanical properties but also spontaneously repair itself at room temperature). When the material is damaged by external factors, the dynamically reversible bonds can work synergistically to achieve self-repair and healing, extending the service life of the buffer film. Therefore, it has broad application prospects in the encapsulation field.
[0008] Preferably, the mass ratio of the modified hydroxyl-terminated silicone oil, isoflurane diisocyanate (IPDI), polypropylene glycol, dimethylolpropionic acid (DMPA), and functionalized polyol chain extender is 5-15:40-60:100:4-6:2-5; and the catalyst is dibutyltin dilauric acid.
[0009] Preferably, the preparation method of the functionalized polyol chain extender includes the following steps:
[0010] S1. Add trimethyl 1,3,5-benzenetricarboxylate to ethanol, heat to 70-80℃, stir to dissolve, then add hydrazine hydrate, stir and react for 2-3 hours. After the reaction is complete, filter under reduced pressure and dry to obtain trimesoyl hydrazine. The molar ratio of trimethyl 1,3,5-benzenetricarboxylate to hydrazine hydrate is 1:6-8. The reaction route is as follows:
[0011]
[0012] S2. Add 4-acetylbenzaldehyde, hydroxylamine hydrochloride, and potassium carbonate to a 75% (w / w) aqueous ethanol solution. Stir and react at room temperature for 5-8 hours. After the reaction is complete, evaporate the solvent, wash with deionized water, filter 2-3 times, and dry to obtain intermediate A. The molar ratio of 4-acetylbenzaldehyde, hydroxylamine hydrochloride, and potassium carbonate is 1:2-2.2:1.5-1.8. The reaction route is as follows:
[0013]
[0014] S3. Add trimellitic acid hydrazide to glacial acetic acid, stir to dissolve, then add intermediate A, and react at 10-20℃ for 3-4 hours. After the reaction is complete, filter under reduced pressure and dry to obtain the functionalized polyol chain extender. The molar ratio of trimellitic acid hydrazide to intermediate A is 1:3-3.5. The reaction route is as follows:
[0015]
[0016] As can be seen from the above steps in preparing functionalized polyol chain extenders, the functionalized polyol chain extenders prepared by this invention not only contain reversible acylhydrazone bonds but also oxime groups (C=N-OH) and rigid benzene ring structures. First, the rigid benzene ring structure can absorb and consume energy when the material is subjected to external stress, thereby improving the mechanical properties of the material. Second, when used as a chain extender, the oxime groups contained therein can react with isocyanate groups to not only generate reversible oxime urethane bonds, but also, because it contains three oxime groups, when reacting with isocyanate groups, it can generate a large crosslinking density and a crosslinked network structure. When subjected to external force, the external force can be dispersed along the crosslinked network structure, thereby improving the mechanical properties of the buffer membrane.
[0017] Preferably, the preparation method of the modified hydroxyl-terminated silicone oil includes the following steps:
[0018] SS1. Under nitrogen protection, mercaptoethanol and allyl mercaptoethanol were added to a flask and stirred to disperse. 30% hydrogen peroxide was added dropwise while stirring, and the mixture was refluxed for 3-5 hours. Ethyl acetate was then added, and the mixture was refluxed for another 1-2 hours. After the reaction was complete, the mixture was separated and purified, the supernatant was removed, dried, filtered under reduced pressure, and distilled to obtain intermediate B, in which the molar ratio of mercaptoethanol to allyl mercaptoethanol was 1:1-1.2. The reaction route is as follows:
[0019]
[0020] As can be seen from the above, in the above reaction, not only are active alkenyl groups and hydroxyl groups introduced into intermediate B, but also disulfide bonds are introduced. Disulfide bonds are a type of dynamically reversible weak covalent bond that can realize the reversible exchange reaction of disulfide bonds or disulfide bond-thiol groups, providing the possibility of self-repair for the subsequent preparation of thin films.
[0021] SS2. Under nitrogen protection, terminal hydrogen silicone oil (Mn = 4000) and intermediate B were added to a flask, stirred and dispersed, and then a catalyst was added. The temperature was raised to 70-80℃ and the reaction was carried out for 5-8 hours. After the reaction was completed, the mixture was centrifuged and dried to obtain modified terminal hydroxyl silicone oil. The catalyst was a 3% (w / w) isopropanol solution of chloroplatinic acid. In this reaction, under the catalysis of chloroplatinic acid, the active silane-hydrogen bonds in the terminal hydrogen silicone oil and the alkenyl groups in intermediate B were hydrosilylated to obtain modified terminal hydroxyl silicone oil, that is, hydroxyl groups and self-healing disulfide bonds were introduced into the modified silicone oil.
[0022] More preferably, in the SS2, the molar ratio of terminal hydrogen silicone oil to intermediate B is 1:2-2.2.
[0023] Beneficial Effects: The functionalized polyol chain extender prepared by this invention contains three hydroxyl groups. When reacting with isocyanate groups, it increases the cross-linking network density of the buffer film, forming a polyurethane network structure with a certain degree of cross-linking. Firstly, the dense cross-linking network structure and the organosilicon structure (with low surface energy) can prevent the material from being contaminated, achieving the purpose of antifouling. Secondly, when subjected to external stress, the functionalized polyol chain extender not only contains a rigid benzene ring structure that can absorb energy and increase mechanical properties, but also, due to its reaction with isocyanate groups to form a cross-linking network structure, can act as a bridge to disperse stress to other molecular chains under stress. Furthermore, when the stress further increases and cracks are generated, the self-healing groups (disulfide bonds, hydrogen bonds, acylhydrazone bonds, and oxime ester bonds) play a role in repairing the cracks, thereby extending the service life of the film. The two are in a progressive, mutually supportive, and interactive relationship. The film prepared by this invention has good mechanical properties, antifouling properties, and self-healing properties. Detailed Implementation
[0024] The following described embodiments are some, but not all, embodiments of the present invention, and are used only to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0025] Example 1
[0026] (1) 50 mmol of 1,3,5-benzenetricarboxylic acid trimethyl ester was added to ethanol, heated to 70 °C, stirred and dissolved, and then 350 mmol of hydrazine hydrate was added. The mixture was stirred and reacted for 3 h. After the reaction was completed, the mixture was filtered under reduced pressure and dried to obtain pyromellitic acid hydrazide.
[0027] (2) 0.5 mol of 4-acetylbenzaldehyde, 1 mol of hydroxylamine hydrochloride and 0.8 mol of potassium carbonate were added to a 75% ethanol aqueous solution. The mixture was stirred and reacted at room temperature for 6 h. After the reaction was completed, the solvent was evaporated, the mixture was washed with deionized water and filtered twice, and then dried to obtain intermediate A.
[0028] (3) Add 40 mmol of pyromellitic acid hydrazide to glacial acetic acid, stir to dissolve, then add 130 mmol of intermediate A, stir and react at 15 °C for 4 h, after the reaction is completed, filter under reduced pressure and dry to obtain functionalized polyol chain extender.
[0029] (4) Under nitrogen protection, 0.12 mol of mercaptoethanol and 0.12 mol of allyl mercaptoethanol were added to a flask and stirred to disperse. 20 g of 30% hydrogen peroxide was added dropwise while stirring. The mixture was refluxed for 5 h, and then 40 mL of ethyl acetate solvent was added. The mixture was refluxed for another 1 h. After the reaction was completed, the mixture was separated and purified. The supernatant was removed, dried, filtered under reduced pressure, and distilled to obtain intermediate B.
[0030] (5) Under nitrogen protection, 0.02 mol of terminal hydrogen silicone oil and 0.044 mol of intermediate B were added to a flask, stirred and dispersed, and then 4 drops of 3% chloroplatinic acid isopropanol solution were added. The temperature was raised to 75°C and the reaction was carried out for 6 hours. After the reaction was completed, the mixture was centrifuged and dried to obtain modified terminal hydroxyl silicone oil.
[0031] (6) Under nitrogen protection, 5g of modified hydroxyl-terminated silicone oil, 40g of IPDI and 100g of polypropylene glycol were added to a flask, stirred and mixed evenly, heated to 70°C and reacted for 2h. Then, 2 drops of dibutyltin dilauric acid and 4g of DMPA were added, heated to 80°C and reacted for 2h. Then, 2g of functionalized polyol chain extender was added, the temperature was raised to 80°C and reacted for 1h. The mixture was naturally cooled to 40°C, 5mL of triethylamine was added for neutralization, and finally 10mL of deionized water was added. The mixture was stirred and mixed evenly, poured into a clean polytetrafluoroethylene film-forming apparatus and dried to form a film. Then, it was placed in a vacuum drying oven at 50°C and dried for 48h to obtain a buffer film for packaging electronic components based on electromagnetic pulse welding.
[0032] Example 2
[0033] (1) 50 mmol of 1,3,5-benzenetricarboxylic acid trimethyl ester was added to ethanol, heated to 75 °C, stirred and dissolved, and then 400 mmol of hydrazine hydrate was added. The mixture was stirred and reacted for 2.5 h. After the reaction was completed, the mixture was filtered under reduced pressure and dried to obtain pyromellitic acid hydrazide.
[0034] (2) 0.5 mol of 4-acetylbenzaldehyde, 1.1 mol of hydroxylamine hydrochloride and 0.8 mol of potassium carbonate were added to a 75% ethanol aqueous solution. The mixture was stirred and reacted at room temperature for 7 h. After the reaction was completed, the solvent was evaporated, the mixture was washed with deionized water and filtered three times, and then dried to obtain intermediate A.
[0035] (3) Add 40 mmol of pyromellitic acid hydrazide to glacial acetic acid, stir to dissolve, then add 140 mmol of intermediate A, stir and react at 10 °C for 4 h, after the reaction is complete, filter under reduced pressure and dry to obtain functionalized polyol chain extender.
[0036] (4) Under nitrogen protection, 0.12 mol of mercaptoethanol and 0.14 mol of allyl mercaptoethanol were added to a flask and stirred to disperse. 20 g of 30% hydrogen peroxide was added dropwise while stirring. The mixture was refluxed for 4 h. Then 40 mL of ethyl acetate solvent was added and the mixture was refluxed for another 2 h. After the reaction was completed, the mixture was separated and purified. The supernatant was removed, dried, filtered under reduced pressure, and distilled to obtain intermediate B.
[0037] (5) Under nitrogen protection, 0.02 mol of terminal hydrogen silicone oil and 0.044 mol of intermediate B were added to a flask, stirred and dispersed, and then 4 drops of 3% chloroplatinic acid isopropanol solution were added. The temperature was raised to 75°C and the reaction was carried out for 6 hours. After the reaction was completed, the mixture was centrifuged and dried to obtain modified terminal hydroxyl silicone oil.
[0038] (6) Under nitrogen protection, 8g of modified hydroxyl-terminated silicone oil, 45g of IPDI and 100g of polypropylene glycol were added to a flask, stirred and mixed evenly, heated to 65°C and reacted for 1h. Then, 2 drops of dibutyltin dilauric acid and 5g of DMPA were added, heated to 75°C and reacted for 3h. Then, 3g of functionalized polyol chain extender was added, the temperature was raised to 85°C and reacted for 2h. The mixture was naturally cooled to 40°C, 5mL of triethylamine was added for neutralization, and finally 10mL of deionized water was added. The mixture was stirred and mixed evenly, poured into a clean polytetrafluoroethylene film-forming apparatus and dried to form a film. Then, it was placed in a vacuum drying oven at 50°C and dried for 48h to obtain a buffer film for packaging electronic components based on electromagnetic pulse welding.
[0039] Example 3
[0040] (1) 50 mmol of 1,3,5-benzenetricarboxylic acid trimethyl ester was added to ethanol, heated to 80 °C, stirred and dissolved, and then 300 mmol of hydrazine hydrate was added to it. The mixture was stirred and reacted for 2 h. After the reaction was completed, the mixture was filtered and dried under reduced pressure to obtain pyromellitic acid hydrazide.
[0041] (2) 0.5 mol of 4-acetylbenzaldehyde, 1.1 mol of hydroxylamine hydrochloride and 0.9 mol of potassium carbonate were added to a 75% ethanol aqueous solution. The mixture was stirred and reacted at room temperature for 8 h. After the reaction was completed, the solvent was evaporated, the mixture was washed with deionized water and filtered twice, and then dried to obtain intermediate A.
[0042] (3) Add 40 mmol of pyromellitic acid hydrazide to glacial acetic acid, stir to dissolve, then add 140 mmol of intermediate A, stir and react at 15 °C for 4 h, after the reaction is complete, filter under reduced pressure and dry to obtain functionalized polyol chain extender.
[0043] (4) Under nitrogen protection, 0.12 mol of mercaptoethanol and 0.13 mol of allyl mercaptoethanol were added to a flask and stirred to disperse. 20 g of 30% hydrogen peroxide was added dropwise while stirring. The mixture was refluxed for 3 h. Then 40 mL of ethyl acetate solvent was added and the mixture was refluxed for another 2 h. After the reaction was completed, the mixture was separated and purified. The supernatant was removed, dried, filtered under reduced pressure, and distilled to obtain intermediate B.
[0044] (5) Under nitrogen protection, 0.02 mol of terminal hydrogen silicone oil and 0.04 mol of intermediate B were added to a flask, stirred and dispersed, and then 4 drops of 3% chloroplatinic acid isopropanol solution were added. The temperature was raised to 80°C and the reaction was carried out for 5 hours. After the reaction was completed, the mixture was centrifuged and dried to obtain modified terminal hydroxyl silicone oil.
[0045] (6) Under nitrogen protection, 10g of modified hydroxyl-terminated silicone oil, 50g of IPDI and 100g of polypropylene glycol were added to a flask, stirred and mixed evenly, heated to 65°C and reacted for 2h. Then, 2 drops of dibutyltin dilauric acid and 6g of DMPA were added, heated to 75°C and reacted for 2h. Then, 4g of functionalized polyol chain extender was added, the temperature was raised to 80°C and reacted for 1h. The mixture was naturally cooled to 40°C, 5mL of triethylamine was added for neutralization, and finally 10mL of deionized water was added. The mixture was stirred and mixed evenly, poured into a clean polytetrafluoroethylene film-forming apparatus and dried to form a film. Then, it was placed in a vacuum drying oven at 50°C and dried for 48h to obtain a buffer film for packaging electronic components based on electromagnetic pulse welding.
[0046] Example 4
[0047] (1) Add 50 mmol of 1,3,5-benzenetricarboxylic acid trimethyl ester to ethanol, heat to 75°C, stir to dissolve, then add 400 mmol of hydrazine hydrate, stir to react for 3 h, after the reaction is completed, filter under reduced pressure and dry to obtain pyromellitic acid hydrazide.
[0048] (2) Add 0.5 mol of 4-acetylbenzaldehyde, 1 mol of hydroxylamine hydrochloride and 0.8 mol of potassium carbonate to a 75% ethanol aqueous solution. Stir the reaction at room temperature for 5 h. After the reaction is complete, evaporate the solvent, wash with deionized water and filter three times, and dry to obtain intermediate A.
[0049] (3) Add 40 mmol of pyromellitic acid hydrazide to glacial acetic acid, stir to dissolve, then add 130 mmol of intermediate A, stir and react at 10 °C for 4 h, after the reaction is complete, filter under reduced pressure and dry to obtain functionalized polyol chain extender.
[0050] (4) Under nitrogen protection, 0.12 mol of mercaptoethanol and 0.13 mol of allyl mercaptoethanol were added to a flask and stirred to disperse. 20 g of 30% hydrogen peroxide was added dropwise while stirring. The mixture was refluxed for 4 h. Then 40 mL of ethyl acetate solvent was added and the mixture was refluxed for another 2 h. After the reaction was completed, the mixture was separated and purified. The supernatant was removed, dried, filtered under reduced pressure, and distilled to obtain intermediate B.
[0051] (5) Under nitrogen protection, 0.02 mol of terminal hydrogen silicone oil and 0.044 mol of intermediate B were added to a flask, stirred and dispersed, and then 4 drops of 3% chloroplatinic acid isopropanol solution were added. The temperature was raised to 70°C and the reaction was carried out for 6 hours. After the reaction was completed, the mixture was centrifuged and dried to obtain modified terminal hydroxyl silicone oil.
[0052] (6) Under nitrogen protection, 13g of modified hydroxyl-terminated silicone oil, 55g of IPDI and 100g of polypropylene glycol were added to a flask, stirred and mixed evenly, heated to 65°C and reacted for 1h. Then, 2 drops of dibutyltin dilauric acid and 5g of DMPA were added, heated to 80°C and reacted for 2h. Then, 4.5g of functionalized polyol chain extender was added, the temperature was raised to 85°C and reacted for 1h. The mixture was naturally cooled to 40°C, 5mL of triethylamine was added for neutralization, and finally 10mL of deionized water was added. The mixture was stirred and mixed evenly, poured into a clean polytetrafluoroethylene film-forming apparatus and dried to form a film. Then, it was placed in a vacuum drying oven at 50°C and dried for 48h to obtain a buffer film for packaging electronic components based on electromagnetic pulse welding.
[0053] Example 5
[0054] (1) Add 50 mmol of 1,3,5-benzenetricarboxylic acid trimethyl ester to ethanol, heat to 75°C, stir to dissolve, then add 400 mmol of hydrazine hydrate, stir to react for 3 h, after the reaction is completed, filter under reduced pressure and dry to obtain pyromellitic acid hydrazide.
[0055] (2) 0.5 mol of 4-acetylbenzaldehyde, 1.1 mol of hydroxylamine hydrochloride and 0.75 mol of potassium carbonate were added to a 75% ethanol aqueous solution. The mixture was stirred and reacted at room temperature for 6 h. After the reaction was completed, the solvent was evaporated, the mixture was washed with deionized water and filtered three times, and then dried to obtain intermediate A.
[0056] (3) Add 40 mmol of pyromellitic acid hydrazide to glacial acetic acid, stir to dissolve, then add 120 mmol of intermediate A, stir and react at 20 °C for 3 h, after the reaction is completed, filter under reduced pressure and dry to obtain functionalized polyol chain extender.
[0057] (4) Under nitrogen protection, 0.12 mol of mercaptoethanol and 0.12 mol of allyl mercaptoethanol were added to a flask and stirred to disperse. 20 g of 30% hydrogen peroxide was added dropwise while stirring. The mixture was refluxed for 4 h. Then 40 mL of ethyl acetate solvent was added and the mixture was refluxed for another 2 h. After the reaction was completed, the mixture was separated and purified. The supernatant was removed, dried, filtered under reduced pressure, and distilled to obtain intermediate B.
[0058] (5) Under nitrogen protection, 0.02 mol of terminal hydrogen silicone oil and 0.042 mol of intermediate B were added to a flask, stirred and dispersed, and then 4 drops of 3% chloroplatinic acid isopropanol solution were added. The temperature was raised to 75°C and the reaction was carried out for 8 hours. After the reaction was completed, the mixture was centrifuged and dried to obtain modified terminal hydroxyl silicone oil.
[0059] (6) Under nitrogen protection, 15g of modified hydroxyl-terminated silicone oil, 60g of IPDI and 100g of polypropylene glycol were added to a flask, stirred and mixed evenly, heated to 65°C and reacted for 2h. Then, 2 drops of dibutyltin dilauric acid and 6g of DMPA were added, heated to 75°C and reacted for 3h. Then, 5g of functionalized polyol chain extender was added, the temperature was raised to 85°C and reacted for 1h. The mixture was naturally cooled to 40°C, 5mL of triethylamine was added for neutralization, and finally 10mL of deionized water was added. The mixture was stirred and mixed evenly, poured into a clean polytetrafluoroethylene film-forming apparatus and dried to form a film. Then, it was placed in a vacuum drying oven at 50°C and dried for 48h to obtain a buffer film for packaging electronic components based on electromagnetic pulse welding.
[0060] Comparative Example 1
[0061] The difference between this comparative example and Example 1 is that 1,4-butanediol is used instead of the functionalized polyol chain extender in step (6), while the remaining steps are the same as in Example 1.
[0062] Comparative Example 2
[0063] The difference between this comparative example and Example 1 is that a commercially available end-hydroxyl silicone oil is used instead of the modified end-hydroxyl silicone oil in step (6), while the other steps are the same as in Example 1.
[0064] Comparative Example 3
[0065] The difference between this comparative example and Example 1 is that dimethyl terephthalate is used instead of trimethyl 1,3,5-benzenetricarboxylate in step (1), as detailed below:
[0066] (1) 50 mmol of dimethyl terephthalate was added to ethanol, heated to 70 °C, and stirred to dissolve. Then 230 mmol of hydrazine hydrate was added, and the mixture was stirred for 3 h. After the reaction was completed, the mixture was filtered under reduced pressure and dried to obtain intermediate C. The reaction route is as follows:
[0067]
[0068] (2) 0.5 mol of 4-acetylbenzaldehyde, 1 mol of hydroxylamine hydrochloride and 0.8 mol of potassium carbonate were added to a 75% ethanol aqueous solution. The mixture was stirred and reacted at room temperature for 6 h. After the reaction was completed, the solvent was evaporated, the mixture was washed with deionized water and filtered twice, and then dried to obtain intermediate A.
[0069] (3) Add 40 mmol of intermediate C to glacial acetic acid, stir to dissolve, then add 90 mmol of intermediate A, and stir to react at 15 °C for 4 h. After the reaction is complete, filter under reduced pressure and dry to obtain the functionalized chain extender. The reaction route is as follows:
[0070]
[0071] (4) Under nitrogen protection, 0.12 mol of mercaptoethanol and 0.12 mol of allyl mercaptoethanol were added to a flask and stirred to disperse. 20 g of 30% hydrogen peroxide was added dropwise while stirring. The mixture was refluxed for 5 h, and then 40 mL of ethyl acetate solvent was added. The mixture was refluxed for another 1 h. After the reaction was completed, the mixture was separated and purified. The supernatant was removed, dried, filtered under reduced pressure, and distilled to obtain intermediate B.
[0072] (5) Under nitrogen protection, 0.02 mol of terminal hydrogen silicone oil and 0.044 mol of intermediate B were added to a flask, stirred and dispersed, and then 4 drops of 3% chloroplatinic acid isopropanol solution were added. The temperature was raised to 75°C and the reaction was carried out for 6 hours. After the reaction was completed, the mixture was centrifuged and dried to obtain modified terminal hydroxyl silicone oil.
[0073] (6) Under nitrogen protection, 5g of modified hydroxyl-terminated silicone oil, 40g of IPDI and 100g of polypropylene glycol were added to a flask, stirred and mixed evenly, heated to 70°C and reacted for 2h. Then, 2 drops of dibutyltin dilauric acid and 4g of DMPA were added, heated to 80°C and reacted for 2h. Then, 2g of functionalized chain extender was added, the temperature was raised to 80°C and reacted for 1h. The mixture was naturally cooled to 40°C, 5mL of triethylamine was added for neutralization, and finally 10mL of deionized water was added. The mixture was stirred and mixed evenly, poured into a clean polytetrafluoroethylene film-forming apparatus and dried to form a film. Then, it was placed in a vacuum drying oven at 50°C and dried for 48h to obtain a buffer film for packaging electronic components based on electromagnetic pulse welding.
[0074] The buffer film was cut into dumbbell-shaped strips of 30mm × 4mm and subjected to tensile testing using an electronic tensile testing machine. The tensile strength S0 was recorded, and the tensile rate was 200mm / min. The film was then cut in half with scissors, and the broken surfaces were quickly glued together. The film was allowed to self-heal at room temperature for 48 hours. The tensile properties were tested again using an electronic tensile testing machine, and the tensile strength S1 after repair was recorded. The repair rate (%) was calculated as S1 / S0 × 100%.
[0075] Table 1:
[0076] Tensile strength / MPa Tensile strength after repair / MPa Repair rate (%) Example 1 33.60 30.04 89.4 Example 2 36.94 33.91 91.8 Example 3 39.45 36.92 93.6 Example 4 40.38 38.08 94.3 Example 5 38.77 36.83 95.0 Comparative Example 1 25.44 11.78 46.3 Comparative Example 2 30.98 25.50 82.3 Comparative Example 3 28.64 25.40 88.7
[0077] As shown in Table 1, the chain extender prepared by this invention can effectively improve the mechanical properties of the buffer membrane. This is because the chain extender prepared by this invention contains a trioxime (C=N-OH) structure, which can form a large cross-linked network structure with the isocyanate group. When subjected to stress, the stress can be dispersed along the molecular chain to other molecular chains, thereby improving the mechanical properties of the material. In Comparative Example 1, 1,4-butanediol was used instead of the chain extender of this invention. It does not contain a trioxime structure or a rigid benzene ring structure, therefore, its mechanical properties are poor. In Comparative Example 3, dimethyl terephthalate was used instead of trimethyl 1,3,5-benzenetricarboxylic acid to prepare a functionalized chain extender with the following structural formula: Although it contains a rigid benzene ring structure, it can only form a single-chain linear structure, not the network structure of this invention. Therefore, its mechanical properties are poor. In Comparative Example 2, a commercially available end-hydroxyl silicone oil was used instead of the modified end-hydroxyl silicone oil of this invention. The modified end-hydroxyl silicone oil of this invention contains polar disulfide bonds, which are polar structures and can form hydrogen bonds with other polar structures on the molecular chain. The formation of these hydrogen bonds can improve the mechanical properties of the material. Therefore, the mechanical properties of Comparative Example 2 are inferior to those of the examples.
[0078] Furthermore, as shown in Table 1, the buffer membrane prepared by the present invention has a good self-healing effect. Comparative Example 1 does not contain acylhydrazone bonds or oxime ester bonds, and Comparative Example 2 does not contain disulfide bonds. The self-healing efficiency of the buffer membrane prepared by the present invention is much higher than that of Comparative Example 1 and Comparative Example 2. This indicates that the dynamic exchange reaction of reversible bonds in the molecular chain of the present invention can effectively achieve the repair of macroscopic cracks, improve the self-healing efficiency of the buffer membrane, and thus increase its service life.
[0079] Contact angle was tested using a contact angle meter. The sample was tested three times with water and diiodomethane, and the average value was taken.
[0080] Table 2:
[0081] Water contact angle / ° Diiodomethane contact angle / ° Example 1 104.6 67.3 Example 2 106.0 70.1 Example 3 108.1 72.3 Example 4 109.5 75.4 Example 5 110.3 77.0 Comparative Example 1 93.4 56.7 Comparative Example 3 98.6 59.4
[0082] As shown in Table 2, the buffer membrane prepared by this invention has a high contact angle with water and diiodomethane. The larger the contact angle, the lower the surface energy and the better the antifouling effect. In Comparative Example 3, dimethyl terephthalate was used instead of trimethyl 1,3,5-benzenetricarboxylate, but it can only form a single-chain linear structure and the crosslinking density is not as good as the chain extender prepared by this invention. The chain extender prepared by this invention has a high crosslinking density and can form a dense film on the material surface. Together with the low surface energy organosilicon long chain, it synergistically improves the antifouling effect of the material.
[0083] The buffer film prepared by this invention has excellent mechanical properties, self-healing properties, and anti-fouling properties, and has broad application prospects in the field of electronic component packaging.
[0084] The above embodiments are only for illustrating the technical solutions and features of the present invention, and are intended to enable those skilled in the art to implement them better. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention are within the scope of protection of the present invention. The parts not described in detail are prior art.
Claims
1. An electromagnetic pulse welding-based cushion film for electronic component packaging, characterized by, The preparation method of the buffer film comprises the following steps: Under the protection of nitrogen, the modified hydroxyl-terminated silicone oil, IPDI, polyoxypropylene glycol are added into a flask, stirred and uniformly mixed, heated to 65-70 DEG C, reacted for 1-2h, then the catalyst and DMPA are added, heated to 75-80 DEG C, reacted for 2-3h, then the functional polyol chain extender is added, the temperature is increased to 80-85 DEG C, reacted for 1-2h, naturally cooled to 40 DEG C, then triethylamine is added dropwise for neutralization, finally deionized water is added, stirred and uniformly mixed, poured into a clean polytetrafluoroethylene film former, dried into a film, placed in a vacuum drying oven at 50 DEG C for baking for 48h, and the buffer film for packaging electronic components based on electromagnetic pulse welding is obtained.
2. The cushioning film for an electronic component package based on electromagnetic pulse welding according to claim 1, characterized by, The mass ratio of the modified hydroxyl-terminated silicone oil, IPDI, polyoxypropylene glycol, DMPA and functional polyol chain extender is 5-15:40-60:100:4-6:2-5; the catalyst is dibutyltin dilaurate.
3. The cushioning film for an electronic component package based on electromagnetic pulse welding according to claim 1, wherein The preparation method of the functional polyol chain extender comprises the following steps: S1, 1, 3, 5-trimethyl benzene tricarboxylate is added into ethanol, heated to 70-80 DEG C, stirred and dissolved, then hydrazine hydrate is added, stirred and reacted for 2-3h, after the reaction is completed, dried by filtration under reduced pressure, and the hydrazide of trimesic acid is obtained; S2, 4-acetylbenzaldehyde, hydroxylamine hydrochloride and potassium carbonate are added into 75% ethanol aqueous solution, stirred and reacted at room temperature for 5-8h, after the reaction is completed, the solvent is distilled off, washed with deionized water for 2-3 times, dried, and the intermediate A is obtained; S3, the hydrazide of trimesic acid is added into glacial acetic acid, stirred and dissolved, then the intermediate A is added, stirred and reacted at 10-20 DEG C for 3-4h, after the reaction is completed, dried by filtration under reduced pressure, and the functional polyol chain extender is obtained.
4. The cushioning film for an electronic component package based on electromagnetic pulse welding according to claim 3, characterized by, In S1, the molar ratio of 1, 3, 5-trimethyl benzene tricarboxylate and hydrazine hydrate is 1:6-8.
5. The cushioning film for an electronic component package based on electromagnetic pulse welding according to claim 3, wherein In S2, the molar ratio of 4-acetylbenzaldehyde, hydroxylamine hydrochloride and potassium carbonate is 1:2-2.2:1.5-1.
8.
6. The cushioning film for an electronic component package based on electromagnetic pulse welding according to claim 3, wherein In S3, the molar ratio of the hydrazide of trimesic acid and the intermediate A is 1:3-3.
5.
7. The cushioning film for an electronic component package based on electromagnetic pulse welding according to claim 1, wherein The preparation method of the modified hydroxyl-terminated silicone oil comprises the following steps: SS1, under the protection of nitrogen, mercaptoethanol and allyl mercaptan are added into a flask, stirred and dispersed, then 30% hydrogen peroxide is added dropwise, stirred and refluxed, reacted for 3-5h, then ethyl acetate solvent is added, continued to reflux for 1-2h, after the reaction is completed, the upper clear liquid is removed, dried, filtered under reduced pressure, and distilled, and the intermediate B is obtained; SS2, under the protection of nitrogen, the intermediate B and the hydrogen-terminated silicone oil are added into a flask, stirred and dispersed, then the catalyst is added, heated to 70-80 DEG C, reacted for 5-8h, after the reaction is completed, centrifuged, dried, and the modified hydroxyl-terminated silicone oil is obtained.
8. The cushioning film for an electronic component package based on electromagnetic pulse welding according to claim 7, wherein In SS1, the molar ratio of mercaptoethanol and allyl mercaptan is 1:1-1.
2.
9. The cushioning film for an electronic component package based on electromagnetic pulse welding according to claim 7, wherein In SS2, the molar ratio of the intermediate B and the hydrogen-terminated silicone oil is 1:2-2.
2.
10. The cushioning film for an electronic component package based on electromagnetic pulse welding according to claim 7, wherein In the SS2, the catalyst is a 3% mass fraction chloroplatinic acid isopropanol solution.