Novel high-speed server FFC cable and preparation method thereof

Abstract

This application discloses a novel high-speed server FFC cable and its preparation method, relating to the field of flexible flat cable technology. The cable includes a pre-treated ultrathin conductor, a microporous dielectric layer, and a hot melt adhesive layer. The hot melt adhesive layer comprises 35-50 parts polyester resin, 10-18 parts polyolefin elastomer, 8-12 parts tackifying resin, 5-8 parts nano-silica, 2-4 parts boron nitride, 3-5 parts isocyanate curing agent, 0.05-0.1 parts catalyst, and 40-60 parts solvent. The microporous dielectric layer comprises 45-60 parts modified polyphenylene ether resin, 12-20 parts liquid crystal polymer, 8-15 parts hollow glass microspheres, 5-10 parts nano-silica, 3-6 parts compatibilizer, 0.8-2 parts foaming agent, 0.2-0.5 parts nucleating agent, 10-15 parts high-efficiency flame retardant, and 0.3-0.6 parts antioxidant. The pre-treated ultrathin conductor is obtained by surface micro-etching of copper foil followed by modified graphene treatment. The FFC line provided in this application features high-speed signal transmission, low loss, and high reliability.

Description

Technical Field

[0001] This application relates to the field of flexible flat cable technology, and in particular to a novel high-speed server FFC cable and its preparation method. Background Technology

[0002] With the rapid development of the global artificial intelligence, big data, and cloud computing industries, 800G / 1.6T high-speed optical modules, GPU servers, and high-density data centers are experiencing explosive growth, leading to a surge in demand for short-distance, high-speed interconnects within these devices. FFC (Flexible Flat Cable), as a core interconnect component, offers advantages such as thinness, flexibility, convenient cabling, and controllable cost, making it a key component for signal transmission within servers.

[0003] Traditional FFC cables use conventional dielectric materials such as PI and PET, which suffer from high dielectric constant, high dielectric loss, severe high-frequency signal attenuation, and poor impedance stability, failing to meet the requirements of high-speed signal transmission of 112Gbps and above. Currently, high-end high-speed FFC products and core dielectric materials rely heavily on imports, posing high supply chain security risks and keeping costs high. The global market for high-speed FFC cables for data centers and servers is experiencing a compound annual growth rate exceeding 15%, and with continued investment in domestic computing infrastructure, the demand for domestic substitution is urgent, indicating a vast market potential. Therefore, there is an urgent need to develop a high-speed server FFC cable using a new dielectric material to address the problems of high dielectric constant, high dielectric loss, severe high-frequency signal attenuation, and poor impedance stability in existing FFC cables. Summary of the Invention

[0004] To address the problems of high dielectric constant, large dielectric loss, severe high-frequency signal attenuation, and poor impedance stability in existing FFC cables, this application provides a novel high-speed server FFC cable and its fabrication method.

[0005] This application provides a novel high-speed server FFC cable, which adopts the following technical solution:

[0006] A novel high-speed server FFC line includes a pre-treated ultrathin conductor, a microporous dielectric layer, and a hot melt adhesive layer;

[0007] The hot melt adhesive layer raw materials include, by weight: 35-50 parts polyester resin, 10-18 parts polyolefin elastomer, 8-12 parts tackifying resin, 5-8 parts nano silica, 2-4 parts boron nitride, 3-5 parts isocyanate curing agent, 0.05-0.1 parts catalyst, and 40-60 parts solvent.

[0008] The microporous dielectric layer raw materials include, by weight: 45-60 parts modified polyphenylene ether resin, 12-20 parts liquid crystal polymer, 8-15 parts hollow glass microspheres, 5-10 parts nano silica, 3-6 parts compatibilizer, 0.8-2 parts foaming agent, 0.2-0.5 parts nucleating agent, 10-15 parts high-efficiency flame retardant, and 0.3-0.6 parts antioxidant.

[0009] Preferably, the pretreated ultrathin conductor is obtained by micro-etching the surface of copper foil and then treating it with modified graphene.

[0010] Preferably, the modified polyphenylene ether resin is prepared from the following raw materials in parts by weight: 4-8 parts polyphenylene ether, 12-24 parts toluene, 16-64 parts sodium hydroxide, 3-6 parts dichloromethane, 0.14-0.28 parts tetrabutylammonium bromide, 17-64 parts water, and 200-400 parts epichlorohydrin.

[0011] Preferably, the method for preparing the modified polyphenylene ether resin includes the following steps:

[0012] Dissolve 4-8 parts of polyphenylene ether in 12-24 parts of toluene, heat to 60-70℃ and stir to dissolve, obtaining a polyphenylene ether solution; add 16-64 parts of sodium hydroxide to 15-60 parts of water and stir to dissolve, obtaining a sodium hydroxide solution, add the sodium hydroxide solution to the polyphenylene ether solution, stir evenly, add 3-6 parts of dichloromethane, and react in a nitrogen atmosphere for 4-6 hours; after cooling to room temperature, add 0.14-0.28 parts of tetrabutylammonium bromide to 2-4 parts of water and dissolve completely, then add to the mixed solution; finally add 200-400 parts of epichlorohydrin and react for 14-18 hours; after the reaction is complete, wash the product several times with ethanol and filter, and finally dry in a vacuum drying oven at 60-70℃ for 12-16 hours to obtain modified post-epoxy polyphenylene ether.

[0013] Preferably, the high-efficiency flame retardant is prepared from the following raw materials in parts by weight: 4-8 parts terephthalaldehyde, 10.3-20.6 parts p-aminobenzenesulfonamide, 75-150 parts anhydrous ethanol, 13-26 parts 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 75-150 parts tetrahydrofuran.

[0014] Preferably, the preparation method of the high-efficiency flame retardant includes the following steps:

[0015] 4-8 parts of terephthalaldehyde, 10.3-20.6 parts of p-aminobenzenesulfonamide, and 75-150 parts of anhydrous ethanol were mixed and refluxed at 80-90℃ for 8-10 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with ethanol, and vacuum dried to obtain a solid flame retardant intermediate. The flame retardant intermediate was then mixed with 13-26 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 75-150 parts of tetrahydrofuran. The mixture was refluxed at 80-90℃ for 24-30 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with ethanol, and vacuum dried to obtain a high-efficiency flame retardant.

[0016] This application provides a novel method for manufacturing a high-speed server FFC cable, which employs the following technical solution:

[0017] A novel method for preparing a high-speed server FFC cable includes the following steps:

[0018] S1. Mix 45-60 parts of modified polyphenylene ether resin with 12-20 parts of liquid crystal polymer and 3-6 parts of compatibilizer for 10-15 min, then add 8-15 parts of hollow glass microspheres, 5-10 parts of nano silica, 10-15 parts of high-efficiency flame retardant and 0.3-0.6 parts of antioxidant, and knead for 5-10 min; then add 0.8-2 parts of foaming agent and 0.2-0.5 parts of nucleating agent, and knead for 2-5 min, then extrude and cast the mixture using a twin-screw extruder; subsequently, foam the mixture to obtain a microporous film; after biaxial stretching, wind it up to obtain a microporous dielectric layer film;

[0019] S2. Dissolve 35-50 parts of polyester resin, 10-18 parts of polyolefin elastomer, and 8-12 parts of tackifying resin in 40-60 parts of solvent and stir for 2-3 hours; then add 5-8 parts of nano silica, 2-4 parts of boron nitride, 3-5 parts of isocyanate curing agent, and 0.05-0.1 parts of catalyst, and disperse evenly to obtain a hot melt adhesive; then use a coating machine to coat the hot melt adhesive onto a release PET film, and after drying, obtain a hot melt adhesive film;

[0020] S3. After the hot melt adhesive film and the microporous dielectric film are stacked according to the structure of hot melt adhesive film / microporous dielectric film / hot melt adhesive film, they are laminated by hot press laminating machine at a temperature of 130-140℃ and a pressure of 3-5MPa to obtain a pre-composite film; then the pre-treated ultrathin conductor is placed between the two pre-composite films, and after vacuum lamination, it is cooled to room temperature to obtain the high-speed server FFC line.

[0021] Preferably, the method for preparing the pretreated ultrathin conductor includes the following steps:

[0022] T1. After ultrasonic cleaning with acetone, copper foil is placed in a mixed solution of citric acid and sodium persulfate for micro-etching for 30-40 seconds, then rinsed with deionized water and dried with nitrogen; finally, H2 / N2 reduction annealing is performed at 150-160℃ for 30-40 minutes to obtain pretreated copper foil.

[0023] T2. The modified graphene is dispersed in N-methylpyrrolidone to obtain a modified graphene dispersion; it is coated on the surface of a pretreated copper foil and then dried in a nitrogen atmosphere: first at 80-90℃ for 10-15 min, then at 120-130℃ for 20-25 min, and finally at 180-190℃ for 30-40 min to obtain the pretreated ultrathin conductor.

[0024] Preferably, the method for preparing the modified graphene includes the following steps:

[0025] Graphene oxide was dispersed in ethanol under ultrasonic conditions, followed by the addition of boric acid and ammonia. The mixture was stirred at 60-70°C for 8-12 hours, cooled to room temperature, washed, and dried at 80-100°C. Finally, it was reduced in a microwave environment for 3-5 minutes to obtain modified graphene.

[0026] Preferably, the mass ratio of graphene oxide:boric acid:ammonia is 1:0.5-2:2-5.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. This application uses epoxy-terminated polyphenylene ether (PPE) as the core matrix of the microporous dielectric layer. Through the chemical modification reaction of PPE with epichlorohydrin, highly reactive epoxy groups are introduced at the molecular chain ends. This not only retains the intrinsic low dielectric constant and low dielectric loss characteristics of PPE, but also endows it with chemical bonding ability with liquid crystal polymers, inorganic fillers, and hot melt adhesive layers, significantly improving interfacial compatibility and dielectric property uniformity. A composite system of saturated polyester, polyolefin elastomer, and tackifying resin, combined with a blocked isocyanate curing agent, achieves a staged reaction characteristic of low-temperature unsealing and high-temperature curing. The introduction of nano-silica and boron nitride reduces the coefficient of thermal expansion while imparting a certain thermal conductivity to the adhesive layer, which helps dissipate heat during high-frequency operation. The pre-composite process of the hot melt adhesive layer and the microporous dielectric layer reserves flow space for conductor embedding during subsequent vacuum lamination. Vacuum lamination enables the adhesive layer to fully fill the conductor gaps and complete cross-linking and curing, forming a dense sandwich structure, ensuring interlayer peel strength and long-term reliability.

[0029] 2. This application forms a rigid framework containing imine bonds and sulfonamide groups through the condensation reaction of terephthalaldehyde and p-aminobenzenesulfonamide, and then undergoes a deep reaction with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to introduce the phosphaphenanthrene structure into the molecular chain, which has a highly efficient flame retardant effect; moreover, this flame retardant has good compatibility with the polyphenylene ether matrix, avoids the interference of traditional brominated flame retardants on high-frequency signals, and effectively reduces dielectric loss.

[0030] 3. This application reduces the surface roughness of copper foil by mildly micro-etching it with citric acid and sodium persulfate, which ensures mechanical anchoring with the graphene layer and avoids high-frequency signal scattering caused by excessive roughness. Subsequently, boron-nitrogen-doped graphene is spin-coated to form a conductive layer on the copper surface, which significantly reduces the interfacial contact resistance, effectively reduces skin effect loss, and significantly alleviates the signal attenuation problem caused by the high-frequency skin effect. Detailed Implementation

[0031] The present application will be further described in detail below with reference to the embodiments.

[0032] The chemical reagents used in the preparation examples, embodiments, and comparative examples provided in this invention are all commercially available products, and their brands and manufacturers are as follows:

[0033] Polyphenylene oxide (PPE), Shanghai Maclean Biochemical Technology Co., Ltd., Product No.: P909220;

[0034] Epichlorohydrin, Shanghai Maclean Biochemical Technology Co., Ltd., Product No.: E808936;

[0035] Liquid crystal polymer, Taizhou Kerui Biotechnology Co., Ltd.;

[0036] Polyester resin, Nantong Runfeng Petrochemical Co., Ltd.;

[0037] Polyolefin elastomers, Nantong Runfeng Petrochemical Co., Ltd.;

[0038] Isocyanate curing agent, Ningbo Laitong New Material Technology Co., Ltd.;

[0039] Hollow glass microspheres, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0040] SEBS-g-MAH, Shanghai Jiadeer Chemical Technology Co., Ltd.;

[0041] Hydrogenated petroleum resin, Guangdong Wengjiang Chemical Reagent Co., Ltd., No.: 110-0#;

[0042] Nano-talc powder, Liyang Ruipu New Materials Co., Ltd.;

[0043] Azodicarbonamide, Shandong Anda Chemical Technology Co., Ltd.;

[0044] Antioxidant 1010, Shanghai Maclean Biochemical Technology Co., Ltd., Product No.: P829612.

[0045] Preparation Example 1: Preparation of Modified Polyphenylene Ether Resin

[0046] Preparation Example 1.1

[0047] 4g of polyphenylene ether was dissolved in 12g of toluene and heated to 60℃ with stirring to obtain a polyphenylene ether solution. 16g of sodium hydroxide was added to 15g of water and stirred to obtain a sodium hydroxide solution. The sodium hydroxide solution was added to the polyphenylene ether solution and stirred evenly. Then, 3g of dichloromethane was added and reacted in a nitrogen atmosphere for 4 hours. After cooling to room temperature, 0.14g of tetrabutylammonium bromide was dissolved in 2g of water and added to the mixed solution. Finally, 200g of epichlorohydrin was added and reacted for 14 hours. After the reaction was completed, the product was washed three times with ethanol and then filtered. Finally, it was dried in a vacuum drying oven at 60℃ for 12 hours to obtain the modified post-epoxy polyphenylene ether.

[0048] Preparation Example 1.2

[0049] 6g of polyphenylene ether was dissolved in 18g of toluene and heated to 65℃ with stirring to obtain a polyphenylene ether solution. 40g of sodium hydroxide was added to 37.5g of water and stirred to obtain a sodium hydroxide solution. The sodium hydroxide solution was added to the polyphenylene ether solution and stirred evenly. Then, 4.5g of dichloromethane was added and reacted in a nitrogen atmosphere for 5 hours. After cooling to room temperature, 0.21g of tetrabutylammonium bromide was dissolved in 2g of water and added to the mixed solution. Finally, 300g of epichlorohydrin was added and reacted for 16 hours. After the reaction was completed, the product was washed four times with ethanol and then filtered. Finally, it was dried in a vacuum drying oven at 65℃ for 14 hours to obtain the modified post-epoxy polyphenylene ether.

[0050] Preparation Example 1.3

[0051] 8g of polyphenylene ether was dissolved in 24g of toluene and heated to 70℃ with stirring to obtain a polyphenylene ether solution. 64g of sodium hydroxide was added to 60g of water and stirred to obtain a sodium hydroxide solution. The sodium hydroxide solution was added to the polyphenylene ether solution and stirred evenly. Then, 6g of dichloromethane was added and reacted in a nitrogen atmosphere for 6 hours. After cooling to room temperature, 0.28g of tetrabutylammonium bromide was dissolved in 4g of water and added to the mixed solution. Finally, 400g of epichlorohydrin was added and reacted for 18 hours. After the reaction was completed, the product was washed five times with ethanol and then filtered. Finally, it was dried in a vacuum drying oven at 70℃ for 16 hours to obtain the modified post-epoxy polyphenylene ether.

[0052] Preparation Example 2: Preparation of High-Efficiency Flame Retardant

[0053] Preparation Example 2.1

[0054] 4g of terephthalaldehyde, 10.3g of p-aminobenzenesulfonamide, and 75g of anhydrous ethanol were mixed and refluxed at 80℃ for 8h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with ethanol, and vacuum dried at 60℃ to obtain a solid flame retardant intermediate. The obtained flame retardant intermediate was mixed with 13g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 75g of tetrahydrofuran. The mixture was refluxed at 80℃ for 24h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with ethanol, and vacuum dried at 60℃ to obtain a high-efficiency flame retardant.

[0055] Preparation Example 2.2

[0056] 6 g of terephthalaldehyde, 15.5 g of p-aminobenzenesulfonamide, and 112.5 g of anhydrous ethanol were mixed and refluxed at 85 °C for 9 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with ethanol, and vacuum dried at 65 °C to obtain a solid flame retardant intermediate. The obtained flame retardant intermediate was mixed with 19.5 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 112.5 g of tetrahydrofuran. The mixture was refluxed at 85 °C for 24 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with ethanol, and vacuum dried at 65 °C to obtain a high-efficiency flame retardant.

[0057] Preparation Example 2.3

[0058] 8g of terephthalaldehyde, 20.6g of p-aminobenzenesulfonamide, and 150g of anhydrous ethanol were mixed and refluxed at 90℃ for 10h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with ethanol, and vacuum dried at 70℃ to obtain a solid flame retardant intermediate. The obtained flame retardant intermediate was mixed with 26g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 150g of tetrahydrofuran. The mixture was refluxed at 90℃ for 30h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with ethanol, and vacuum dried at 70℃ to obtain a high-efficiency flame retardant.

[0059] Example 1

[0060] S1. 45g of the modified polyphenylene ether resin prepared in Preparation Example 1.1 was mixed with 12g of liquid crystal polymer and 3g of compatibilizer SEBS-g-MAH for 10min. Then, 8g of hollow glass microspheres, 5g of nano silica, 10g of high-efficiency flame retardant prepared in Preparation Example 2.1, and 0.3g of antioxidant 1010 were added and mixed for 5min. Then, 0.8g of foaming agent azodicarbonamide and 0.2g of nucleating agent nano talc were added and mixed for 2min. The mixture was then extruded and cast into a film using a twin-screw extruder at a die head temperature of 175℃. Subsequently, the film was foamed in a foaming oven at 160℃ for 30s to obtain a microporous film. After biaxial stretching, the longitudinal stretch ratio was 1.2 and the transverse stretch ratio was 1.1. The film was then wound up to obtain a microporous dielectric layer film with a thickness of 30μm.

[0061] S2. Dissolve 35g polyester resin, 10g polyolefin elastomer, and 8g hydrogenated petroleum resin (tackifying resin) in 40g toluene solvent and stir for 2 hours. Then add 5g nano silica, 2g boron nitride, 3g isocyanate curing agent, and 0.05g dibutyltin dilaurate catalyst and disperse evenly to obtain hot melt adhesive. Then use a microgravure coating machine to coat the hot melt adhesive onto a release PET film. After drying, a hot melt adhesive film with a thickness of 15μm is obtained.

[0062] S3. Preparation of pretreated ultrathin conductors:

[0063] S31. 100 mg of graphene oxide was dispersed in 100 mL of ethanol under ultrasonic conditions, followed by the addition of 50 mg of boric acid and 200 mg of ammonia water. The mixture was stirred at 60 °C for 8 h, cooled to room temperature, washed, dried at 80 °C, and finally reduced in a microwave environment for 3 min to obtain modified graphene.

[0064] S32. After ultrasonically cleaning a 9μm thick copper foil with acetone for 10 min, it was placed in a mixed solution of 50g / L citric acid and 20g / L sodium persulfate for micro-etching for 30 s. Then, it was rinsed with deionized water until the waste liquid was neutral and dried with nitrogen. Finally, it was subjected to H2 / N2 (hydrogen-nitrogen ratio of 5:95) reduction annealing at 150℃ for 30 min to obtain the pretreated copper foil.

[0065] S33. 300 mg of modified graphene was dispersed in 100 mL of N-methylpyrrolidone to obtain a modified graphene dispersion; it was then coated onto the surface of a pretreated copper foil by spin coating and dried in a nitrogen atmosphere: first at 80 °C for 10 min, then at 120 °C for 20 min, and finally at 180 °C for 30 min to obtain a pretreated ultrathin conductor.

[0066] S4. After stacking the hot melt adhesive film and the microporous dielectric film according to the structure of hot melt adhesive film / microporous dielectric film / hot melt adhesive film, the film is laminated by hot pressing at a temperature of 130℃ and a pressure of 3MPa to obtain a pre-composite film. Then, the pre-treated ultrathin conductor is placed between the two pre-composite films, and a vacuum lamination process is performed at a vacuum degree of -0.095MPa, a temperature of 150℃, a pressure of 5MPa, and a holding pressure of 10 minutes. After cooling to room temperature, the high-speed server FFC line is obtained.

[0067] Example 2

[0068] S1. 52.5g of the modified polyphenylene ether resin prepared in Preparation Example 1.2 was mixed with 16g of liquid crystal polymer and 4.5g of compatibilizer SEBS-g-MAH for 13min. Then, 11.5g of hollow glass microspheres, 7.5g of nano silica, 12.5g of high-efficiency flame retardant prepared in Preparation Example 2.2, and 0.45g of antioxidant 1010 were added and mixed for 8min. Then, 1.4g of foaming agent azodicarbonamide and 0.35g of nucleating agent nano talc were added and mixed for 3.5min. The mixture was then extruded and cast into a film using a twin-screw extruder at a die head temperature of 177.5℃. Subsequently, the film was foamed in a foaming oven at 165℃ for 35s to obtain a microporous film. After biaxial stretching, the longitudinal stretch ratio was 1.2 and the transverse stretch ratio was 1.1. The film was then wound up to obtain a microporous dielectric layer film with a thickness of 40μm.

[0069] S2. Dissolve 42.5g of polyester resin, 14g of polyolefin elastomer, and 10g of hydrogenated petroleum resin (a tackifying resin) in 50g of toluene solvent and stir for 2.5h. Then add 6.5g of nano silica, 3g of boron nitride, 4g of isocyanate curing agent, and 0.075g of dibutyltin dilaurate catalyst, and disperse evenly to obtain a hot melt adhesive. Then use a microgravure coating machine to coat the hot melt adhesive onto a release PET film. After drying, a hot melt adhesive film with a thickness of 18μm is obtained.

[0070] S3. Preparation of pretreated ultrathin conductors:

[0071] S31. 100 mg of graphene oxide was dispersed in 130 mL of ethanol under ultrasonic conditions, followed by the addition of 120 mg of boric acid and 350 mg of ammonia water. The mixture was stirred at 65 °C for 10 h, cooled to room temperature, washed, dried at 90 °C, and finally reduced in a microwave environment for 4 min to obtain modified graphene.

[0072] S32. After ultrasonically cleaning a 15μm thick copper foil with acetone for 15min, it is placed in a mixed solution of 50g / L citric acid and 20g / L sodium persulfate for micro-etching for 35s. Then, it is rinsed with deionized water until the waste liquid is neutral and dried with nitrogen. Finally, it is subjected to H2 / N2 (hydrogen-nitrogen ratio of 5:95) reduction annealing at 155℃ for 35min to obtain the pretreated copper foil.

[0073] S33. 350 mg of modified graphene was dispersed in 100 mL of N-methylpyrrolidone to obtain a modified graphene dispersion; it was then coated onto the surface of a pretreated copper foil by spin coating and dried in a nitrogen atmosphere: first at 85 °C for 13 min, then at 125 °C for 23 min, and finally at 185 °C for 35 min to obtain a pretreated ultrathin conductor.

[0074] S4. After stacking the hot melt adhesive film and the microporous dielectric film according to the structure of hot melt adhesive film / microporous dielectric film / hot melt adhesive film, the film is laminated by a hot press laminating machine at a temperature of 135℃ and a pressure of 4MPa to obtain a pre-composite film. Then, the pre-treated ultrathin conductor is placed between the two pre-composite films, and a vacuum lamination process is performed at a vacuum degree of -0.098MPa, a temperature of 155℃, a pressure of 6MPa, and a holding pressure of 12 minutes. After cooling to room temperature, the high-speed server FFC line is obtained.

[0075] Example 3

[0076] S1. 60g of the modified polyphenylene ether resin prepared in Preparation Example 1.3 was mixed with 20g of liquid crystal polymer and 6g of compatibilizer SEBS-g-MAH for 15min. Then, 15g of hollow glass microspheres, 10g of nano silica, 15g of high-efficiency flame retardant prepared in Preparation Example 2.3 and 0.6g of antioxidant 1010 were added and mixed for 10min. Then, 2g of foaming agent azodicarbonamide and 0.5g of nucleating agent nano talc were added and mixed for 5min. The mixture was then extruded and cast into a film using a twin-screw extruder at a die head temperature of 180℃. Subsequently, the film was foamed in a foaming oven at 170℃ for 40s to obtain a microporous film. After biaxial stretching, the longitudinal stretch ratio was 1.2 and the transverse stretch ratio was 1.1. The film was then wound up to obtain a microporous dielectric layer film with a thickness of 50μm.

[0077] S2. Dissolve 35g polyester resin, 10g polyolefin elastomer, and 8g hydrogenated petroleum resin (tackifying resin) in 40g toluene solvent and stir for 2 hours. Then add 5g nano silica, 2g boron nitride, 3g isocyanate curing agent, and 0.05g dibutyltin dilaurate catalyst and disperse evenly to obtain hot melt adhesive. Then use a microgravure coating machine to coat the hot melt adhesive onto a release PET film. After drying, a hot melt adhesive film with a thickness of 20μm is obtained.

[0078] S3. Preparation of pretreated ultrathin conductors:

[0079] S31. 100 mg of graphene oxide was dispersed in 150 mL of ethanol under ultrasonic conditions, followed by the addition of 200 mg of boric acid and 500 mg of ammonia water. The mixture was stirred at 70 °C for 12 h, cooled to room temperature, washed, dried at 100 °C, and finally reduced in a microwave environment for 5 min to obtain modified graphene.

[0080] S32. After ultrasonically cleaning a 20μm thick copper foil with acetone for 20min, it is placed in a mixed solution of 50g / L citric acid and 20g / L sodium persulfate for micro-etching for 40s. Then, it is rinsed with deionized water until the waste liquid is neutral and dried with nitrogen. Finally, it is subjected to H2 / N2 (hydrogen-nitrogen ratio of 5:95) reduction annealing at 160℃ for 40min to obtain the pretreated copper foil.

[0081] S33. 400 mg of modified graphene was dispersed in 100 mL of N-methylpyrrolidone to obtain a modified graphene dispersion; it was then coated onto the surface of a pretreated copper foil by spin coating and dried under nitrogen: first at 90 °C for 15 min, then at 130 °C for 25 min, and finally at 190 °C for 40 min to obtain a pretreated ultrathin conductor.

[0082] S4. After stacking the hot melt adhesive film and the microporous dielectric film according to the structure of hot melt adhesive film / microporous dielectric film / hot melt adhesive film, the film is laminated by a hot press laminating machine at a temperature of 140℃ and a pressure of 5MPa to obtain a pre-composite film. Then, the pre-treated ultrathin conductor is placed between the two pre-composite films, and a vacuum lamination process is performed at a vacuum degree of -0.100MPa, a temperature of 160℃, a pressure of 7MPa, and a holding pressure of 15 minutes. After cooling to room temperature, the high-speed server FFC line is obtained.

[0083] Comparative Example 1

[0084] The difference between Comparative Example 1 and Example 1 is that unmodified polyphenylene ether was used in Comparative Example 1 instead of the modified polyphenylene ether resin prepared in Preparation Example 1.1.

[0085] Comparative Example 2

[0086] The difference between Comparative Example 2 and Example 1 is that decabromodiphenyl ethane is used in Comparative Example 2 instead of the high-efficiency flame retardant prepared in Preparation Example 2.1.

[0087] Comparative Example 3

[0088] The difference between Comparative Example 3 and Example 1 is that no hot melt adhesive layer is added in Comparative Example 3.

[0089] Performance testing

[0090] 1. Wire bending test: The formed FFC wire was subjected to a reciprocating bending test at 85℃, with a test speed of 100 times / min. After 100,000 tests, the wire was observed for cracking and delamination. The results are shown in Table 1.

[0091] II. High-temperature welding performance test of wire: The formed FFC wire was immersed in a tin furnace at 260℃ for 30 seconds, and the delamination of the finished wire was observed. The results are shown in Table 1.

[0092] III. Insulation resistance test of wire: Apply a DC voltage of 500V between two adjacent conductors of the FFC wire for 60s and test its resistance value. The results are shown in Table 1.

[0093] The specific test results are as follows:

[0094] Table 1 Performance Test Results

[0095] Wire flex test High-temperature welding performance test of wire Wire insulation resistance test Example 1 No abnormalities No delamination >500MΩ Example 2 No abnormalities No delamination >500MΩ Example 3 No abnormalities No delamination >500MΩ Comparative Example 1 Delamination occurs No delamination >500MΩ Comparative Example 2 Delamination occurs Delamination occurs >500MΩ Comparative Example 3 Delamination occurs Delamination occurs <500MΩ

[0096] As can be seen from the test results in Table 1, the FFC cable provided in this application, and the FFC cable obtained by the novel high-speed server FFC cable and its preparation method provided in this application, have no delamination and a resistance value >500MΩ, demonstrating excellent overall performance.

[0097] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A novel high-speed server FFC cable, characterized in that: This includes pre-treated ultrathin conductors, microporous dielectric layers, and hot melt adhesive layers; The hot melt adhesive layer raw materials include, by weight: 35-50 parts polyester resin, 10-18 parts polyolefin elastomer, 8-12 parts tackifying resin, 5-8 parts nano silica, 2-4 parts boron nitride, 3-5 parts isocyanate curing agent, 0.05-0.1 parts catalyst, and 40-60 parts solvent. The microporous dielectric layer raw materials include, by weight: 45-60 parts modified polyphenylene ether resin, 12-20 parts liquid crystal polymer, 8-15 parts hollow glass microspheres, 5-10 parts nano silica, 3-6 parts compatibilizer, 0.8-2 parts foaming agent, 0.2-0.5 parts nucleating agent, 10-15 parts high-efficiency flame retardant, and 0.3-0.6 parts antioxidant.

2. The novel high-speed server FFC cable according to claim 1, characterized in that: The pretreated ultrathin conductor is obtained by micro-etching the surface of copper foil and then treating it with modified graphene.

3. The novel high-speed server FFC cable according to claim 1, characterized in that: The modified polyphenylene ether resin is prepared from the following raw materials in parts by weight: 4-8 parts polyphenylene ether, 12-24 parts toluene, 16-64 parts sodium hydroxide, 3-6 parts dichloromethane, 0.14-0.28 parts tetrabutylammonium bromide, 17-64 parts water, and 200-400 parts epichlorohydrin.

4. The novel high-speed server FFC cable according to claim 3, characterized in that: The preparation method of the modified polyphenylene ether resin includes the following steps: Dissolve 4-8 parts of polyphenylene ether in 12-24 parts of toluene, heat to 60-70℃ and stir to dissolve, obtaining a polyphenylene ether solution; add 16-64 parts of sodium hydroxide to 15-60 parts of water and stir to dissolve, obtaining a sodium hydroxide solution, add the sodium hydroxide solution to the polyphenylene ether solution, stir evenly, add 3-6 parts of dichloromethane, and react in a nitrogen atmosphere for 4-6 hours; after cooling to room temperature, add 0.14-0.28 parts of tetrabutylammonium bromide to 2-4 parts of water and dissolve completely, then add to the mixed solution; finally add 200-400 parts of epichlorohydrin and react for 14-18 hours; after the reaction is complete, wash the product several times with ethanol and filter, and finally dry in a vacuum drying oven at 60-70℃ for 12-16 hours to obtain modified post-epoxy polyphenylene ether.

5. The novel high-speed server FFC cable according to claim 1, characterized in that: The high-efficiency flame retardant is prepared from the following raw materials in parts by weight: 4-8 parts terephthalaldehyde, 10.3-20.6 parts p-aminobenzenesulfonamide, 75-150 parts anhydrous ethanol, 13-26 parts 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 75-150 parts tetrahydrofuran.

6. The novel high-speed server FFC cable according to claim 5, characterized in that: The preparation method of the high-efficiency flame retardant includes the following steps: 4-8 parts of terephthalaldehyde, 10.3-20.6 parts of p-aminobenzenesulfonamide, and 75-150 parts of anhydrous ethanol were mixed and refluxed at 80-90℃ for 8-10 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with ethanol, and vacuum dried to obtain a solid flame retardant intermediate. The flame retardant intermediate was then mixed with 13-26 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 75-150 parts of tetrahydrofuran. The mixture was refluxed at 80-90℃ for 24-30 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with ethanol, and vacuum dried to obtain a high-efficiency flame retardant.

7. A method for preparing a novel high-speed server FFC cable according to any one of claims 1-6, characterized in that: Includes the following steps: S1. Mix 45-60 parts of modified polyphenylene ether resin with 12-20 parts of liquid crystal polymer and 3-6 parts of compatibilizer for 10-15 min, then add 8-15 parts of hollow glass microspheres, 5-10 parts of nano silica, 10-15 parts of high-efficiency flame retardant and 0.3-0.6 parts of antioxidant, and knead for 5-10 min; then add 0.8-2 parts of foaming agent and 0.2-0.5 parts of nucleating agent, and knead for 2-5 min, then extrude and cast the mixture using a twin-screw extruder; subsequently, foam the mixture to obtain a microporous film; after biaxial stretching, wind it up to obtain a microporous dielectric layer film; S2. Dissolve 35-50 parts of polyester resin, 10-18 parts of polyolefin elastomer, and 8-12 parts of tackifying resin in 40-60 parts of solvent and stir for 2-3 hours; then add 5-8 parts of nano silica, 2-4 parts of boron nitride, 3-5 parts of isocyanate curing agent, and 0.05-0.1 parts of catalyst, and disperse evenly to obtain a hot melt adhesive; then use a coating machine to coat the hot melt adhesive onto a release PET film, and after drying, obtain a hot melt adhesive film; S3. After the hot melt adhesive film and the microporous dielectric film are stacked according to the structure of hot melt adhesive film / microporous dielectric film / hot melt adhesive film, they are laminated by hot press laminating machine at a temperature of 130-140℃ and a pressure of 3-5MPa to obtain a pre-composite film; then the pre-treated ultrathin conductor is placed between the two pre-composite films, and after vacuum lamination, it is cooled to room temperature to obtain the high-speed server FFC line.

8. The method for preparing a novel high-speed server FFC cable according to claim 7, characterized in that: The method for preparing the pretreated ultrathin conductor includes the following steps: T1. After ultrasonic cleaning with acetone, copper foil is placed in a mixed solution of citric acid and sodium persulfate for micro-etching for 30-40 seconds, then rinsed with deionized water and dried with nitrogen; finally, H2 / N2 reduction annealing is performed at 150-160℃ for 30-40 minutes to obtain pretreated copper foil. T2. The modified graphene is dispersed in N-methylpyrrolidone to obtain a modified graphene dispersion; it is coated on the surface of a pretreated copper foil and then dried in a nitrogen atmosphere: first at 80-90℃ for 10-15 min, then at 120-130℃ for 20-25 min, and finally at 180-190℃ for 30-40 min to obtain the pretreated ultrathin conductor.

9. The method for preparing a novel high-speed server FFC cable according to claim 8, characterized in that: The method for preparing the modified graphene includes the following steps: Graphene oxide was dispersed in ethanol under ultrasonic conditions, followed by the addition of boric acid and ammonia. The mixture was stirred at 60-70°C for 8-12 hours, cooled to room temperature, washed, and dried at 80-100°C. Finally, it was reduced in a microwave environment for 3-5 minutes to obtain modified graphene.

10. The method for preparing a novel high-speed server FFC cable according to claim 9, characterized in that: The mass ratio of graphene oxide, boric acid, and ammonia is 1:0.5-2:2-5.