Application of adhesive bonding technology in inertial guidance system
Zhao Fugui1,2, Zhang Junying1, Cheng Jue1
(1. Beijing University of Chemical Technology, Beijing 100029, China;2. Qinghai Polytechnic University, Xining 810016, Qinghai, China)
【Abstract】Adhesive bonding technology, as the critical process for the manufacturing and packaging of inertial guidance system, directly determines the precision stability and long term reliability of the system. The core functions of adhesive bonding technology in the assembly of inertial devices, stress isolation and system-level integrated protection, as well as the requirements for adhesive materials and processes with varying performance were introduced in this paper. The impact of existing various types of adhesive on inertial guidance system and their process-induced effect were elaborated, and four common fundamental problems that needed to be addressed when different adhesive was applied to fiber optic gyroscope, namely rapid curing, low stress, volatility and low creep, were analyzed. Meanwhile, the criteria for selecting different fiber optic adhesive and structural design concepts were proposed, and the existing fiber optic adhesive and related research were elaborated. Finally, the research progress of current mainstream fiber optic adhesive and novel materials were summarized, and the future development direction of high performance of adhesive bonding technology in the field of inertial guidance was discussed, providing references for the precision manufacturing, design development of related products.
【Keywords】adhesive bonding technology; inertial guidance system; fiber optic gyroscope; UV curing; low stress; acrylate
Research progress on addition-type silicone rubber tackifier
Wang Xiaochen1,Chai Qian1, Wang Guodong2, Qin Jiaqi3, Lu Haifeng3
（1.Shandong Center for Medical Device Evaluation and Inspection, Jinan 250014, Shandong, China; 2.Changle People's Hospital of Shandong Second Medical University, Changle 262400, Shandong, China; 3. School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, Shandong, China）
【Abstract】Addition-type silicone rubber has attracted extensive attention due to its excellent properties. However, its low surface energy and chemical inertness after curing result in poor bonding property to substrates, which limits its application. Adding tackifiers can effectively enhance the interfacial interaction between silicone rubber and substrates, improving bonding strength, and addressing the difficulty in bonding. The new progress in the design, synthesis and application of tackifiers for addition-type silicone rubber in recent years was briefly reviewed in this paper, and the action mechanisms and modification effects of various types of functional groups were systematically summarized. Research on addition-type silicone rubber tackifiers has indicated that single functional group tackifiers could hardly balance the adaptability to multiple substrates and environmental stability. The synergistic design of multi-functional groups and precise interfacial engineering would be the core directions for improving the performance of tackifiers in the future, which would provide support for breakthroughs in the application of addition-type silicone rubber in high-end manufacturing, new energy and other fields.
【Keywords】addition-type silicone rubber; tackifier; bonding
Research Report
Development of novel BAPP-BMI high temperature resistant adhesive and its curing kinetics
Fan Tianhua, Yu Xinhai
(College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China)
【Abstract】A novel high temperature resistant adhesive (J01) was prepared by compounding and modifying 2,2-bis[4-(4-maleimidophenoxy) phenyl] propane (BAPP-BMI) resin with diallylbisphenol A (DABPA) and diallylbisphenol S (DABPS). The curing kinetics were studied by using differential scanning calorimetry, and the mechanical, electrical, and water absorption properties of the cured material were characterized. The research results showed that the curing process of high temperature resistant adhesive J01 was 190 ℃/2 h+220 ℃/2 h+250 ℃/2 h+275 ℃/2 h, with the apparent activation energy of 102.5 kJ/mol and the reaction order of 0.917. The DABPA/DABPS/BAPP-BMI system had excellent mechanical properties, with impact strength, tensile strength, and bending strength of 37.1 kJ/m², 64.7 MPa, and 93.4 MPa, respectively. The adhesive had good bonding performance, with the tensile shear strength of 15.5 MPa at room temperature. When the temperature was 300 ℃, the shear strength of 4.6 MPa was still retained. The adhesive system maintained excellent dielectric stability over a wide frequency range, with the stable capacitance value of 4.57-4.65 pF, low dielectric constant (3.53-3.58) and low dielectric loss (0.007 78-0.010 80). It had good insulation and excellent dielectric properties. The average water absorption rate of the cured product was measured to be 0.38%. Comprehensive testing analysis showed that the adhesive had good heat resistance, mechanical properties, dielectric properties, and moisture and heat stability, demonstrating broad application prospects in the field of high reliability electronic packaging.
【Keywords】bismaleimide; curing kinetics; mechanical property; dielectric property
Study on epoxy resin adhesive synergistically modified by chopped carbon fiber/carboxyl-terminated liquid nitrile rubber
Zhao Ming, Zhang Xue, Sun Mingming, Zhang Xugang,
Zhang Bin, Yuan Zhigang, Li Jianhui, Wang Lei
(Institute of Petrochemistry Heilongjiang Academy of Sciences, Harbin 150040, Heilongjiang, China)
【Abstract】Chopped carbon fiber, carboxyl-terminated liquid nitrile rubber (CTBN), dicyandiamide and epoxy resin were used as main raw materials, composite adhesive was prepared via three-roll grinding and vacuum stirring process. The bonding properties, bulk mechanical properties, heat resistance and micromorphology of adhesive were characterized. The research results showed that CTBN could improve the single-lap tensile shear strength of epoxy resin, but the decreasing amplitude of shear strength gradually increased with the increase of adhesive layer thickness. After synergistic modification by CTBN and chopped carbon fiber, the shear strength of adhesive was improved within the range of 0.1-3.0 mm adhesive layer thickness, meanwhile, its bulk rigidity and glass transition temperature were increased to some extent, and the fracture surface exhibited a ductile fracture morphology. When the addition amounts of chopped carbon fiber and CTBN were both 20 phr, the shear strength of the adhesive all reached maximum value under the adhesive layer thicknesses of 0.1 mm and 1.0 mm, which were 31.3 MPa and 23.6 MPa, respectively. The composite modification method of chopped carbon fiber and CTBN could effectively improve the shear strength of epoxy adhesive at different adhesive layer thicknesses, providing a reference for the preparation of high-performance special adhesive for thick adhesive layer bonding.
【Keywords】epoxy resin; adhesive; chopped carbon fiber; adhesive layer thickness; modification
Synthesis and properties of high temperature resistant and peelable polyamide-imide adhesive
Liu Jie, Xia Dengzhou, Dai Anbang, Huang Jian, Li Shicheng, Wan Zhongliang
(Wuhu Huishi New Material Technology Co., Ltd., Wuhu 241000, Anhui, China)
【Abstract】In order for polyamide-imide (PAI) adhesive with good wetting properties and high temperature stability during the hot-pressing stage of temporary bonding materials in high temperature process, and controllable glass transition temperature (Tg) after cooling, three types of PAI adhesive (PAI-1, PAI-2, and PAI-3) were synthesized by using 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), 1,12-diaminododecane (DDA), and trimellitic anhydride chloride (TMAC) as monomers and adjusting the ratio of aromatic to aliphatic diamines. Their Tg values were 174, 192, and 222 ℃, respectively. They were coated onto Kapton base film and cured to form an adhesive layer. Subsequently, the film was hot-pressed onto copper foil at 200 ℃, and peel strength tests were carried out after cooling. The research results showed that the matching degree between Tg and bonding temperature significantly affected the peel failure mode and cleanliness. The PAI-2 formula with a Tg close to 200 ℃ could achieve stable debonding dominated by the interface, with a smooth peeling process and no obvious residue or wire drawing on the copper foil surface. Scanning electron microscopy observation revealed the formation of uniform wrinkles on the surface of the adhesive layer after peeling. This morphology was closely related to the release of residual stress caused by thermal mismatch as well as the viscoelastic relaxation/freezing behavior near Tg, which verified the interface dominant delamination mechanism from a microscopic perspective. This study provided practical control strategies for the formulation design and process matching of high temperature resistant and peelable adhesive tape, which showed potential application prospects in high-density packaging, flexible circuit manufacturing, and related fields.
【Keywords】polyamide-imide; glass transition temperature; adhesive; clean debonding; peelable tape
Study on the preparation and performance of cardanol-modified underwater epoxy adhesive
Lu Hongtao¹, Yao Jingjing², Jin Kai ²
(1. Unit 91697 of the Chinese People's Liberation Army, Qingdao 266405, Shandong, China；2. School of Materials Science and Engineering, Ocean University of China, Qingdao 266100, Shandong, China)
【Abstract】An underwater curing agent containing cardanol structure was synthesized by using cardanol, paraformaldehyde and m-xylylenediamine as raw materials via Mannich reaction, and then an underwater epoxy adhesive was prepared by compounding it with E-51 epoxy resin. The influence of synthesis process, curing agent ratio, curing time as well as the dosage of three monomers on the underwater bonding performance and mechanical properties of the adhesive were systematically investigated. The research results showed that the optimal synthesis process of the curing agent was reaction at 90 ℃ for 4 h. The optimal mass ratio of epoxy resin to curing agent was 10∶4, and the performance tended to be stable after underwater curing for 120 h. When the monomer molar ratio n(cardanol)∶n(paraformaldehyde)∶n(m-xylylenediamine)=1∶1∶1.4, the adhesive exhibited the optimal comprehensive performance, with an underwater bonding strength of 9.52 MPa, as well as favorable tensile strength (35 MPa) and compressive strength (80.24 MPa). The study confirmed that the introduction of cardanol effectively improved the toughness, water resistance and curing acceleration effect of the adhesive, but excessive addition could reduce the rigidity of the material and lead to decreases in tensile and compressive strength. This study provided theoretical and experimental foundations for developing epoxy adhesive with both favorable underwater bonding performance and balanced mechanical properties.
【Keywords】underwater curing; epoxy adhesive; Mannich reaction; cardanol
Process and Application
Formulation development of high temperature and high humidity resistant central adhesive and its application in micro speaker
Wang Mengmei, Cheng Zhenzhen, Liu Chunli, Tan Caihua,Zhang Wenyu, Zhou Houqiang, Li Naigang, Wang Hairong
(Goertek Inc., Weifang 261061, Shandong, China)
【Abstract】In response to the problem of bonding failure between the ball top and voice coil of high-power micro speaker under extreme high temperature, high temperature and humidity environments, the effect of key components, including oligomer type, type and compounding of active monomers, antioxidants and photoinitiators on the high temperature resistance, high temperature and humidity resistance of adhesive based on polyurethane modified acrylic UV curing system was investigated systematically in this paper. The research results showed that polycarbonate-based polyurethane acrylate exhibited superior thermal resistance and hydrolysis resistance compared with polyether-based and polyester-based counterparts, owing to the high energy carbonate bonds in its main chain. A complex monomer system consisting of isobornyl ester, N,N-dimethylacrylamide, isooctyl acrylate, and a small amount of tetrahydrofuran acrylate was used to achieve a balance between high bonding strength and excellent aging stability. The addition of hindered phenolic antioxidant 264 at 0.45% (mass fraction, the same below) could effectively inhibit thermal oxidative degradation at extreme high temperature of 190 ℃. The deep layer photoinitiator TPO-L achieved a curing depth greater than 5 mm at a dosage of 1%, overcoming the process bottleneck of incomplete curing in the shadow area of the voice coil. Based on the above optimization, the G001 type central adhesive formulation had been successfully developed. After undergoing high temperature load and constant wet heat life tests, the bonding qualification rate reached 100%, significantly better than commercially available products, providing an innovative material solution for the long-term reliable operation of high-power micro speaker.
【Keywords】center adhesive; high temperature resistance; high temperature and high humidity resistance; micro speaker; formulation development
Failure analysis and countermeasure research on sealing protection of shipborne antenna in marine atmospheric environment
Gao Hua1, Sun Kun1, Shen Xuesong1, Bai Yongping2
(1.The 20th Research Institute of China Electronics Technology Group Corporation, Xi’an, 710068, Shaanxi, China; 2.School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001 Heilongjiang, China)
【Abstract】In response to the water seepage fault occurring on a certain shipborne antenna in marine atmospheric environment, the fault phenomenon was reproduced through damp-heat, salt spray and water spray tests. The research results showed that the original design presented dual sealing failure. The outer 0.3 mm covering generated micropores as a result of grinding and trimming, the inner epoxy adhesive failed to seal the micropores of PMI foam because of excessively low viscosity, and the coupling of the two made water molecules permeate into the cavity along the pores. For this purpose, four improvement measures were proposed: adopting epoxy putty to seal foam micropores, thickening the side edge covering and designing special tooling, introducing a vacuum negative pressure laminating process to eliminate air bubbles, and adjusting the paint surface grade from Grade III to Grade IV to avoid excessive grinding. After verification of multiple batches of production and water spray tests, the sealing performance of the improved antenna was significantly enhanced, and no water seepage faults occurred again. This study clarified the water seepage mechanism, and the proposed comprehensive improvement scheme possessed important reference value for the protection design of similar equipment.
【Keywords】marine atmospheric environment; shipborne antenna; sealing protection; covering; water seepage; process improvement
Study on the influence of different epoxy resins on the performance of silane modified polyether adhesive
Hu Zebo, Sun Yusheng, Liu Yonggang, Lei Musheng, You Renguo
(Wuhan Shuangjian New Materials Co., Ltd., Wuhan 430040, Hubei, China)
【Abstract】In order to investigate the influence and mechanism of different types of epoxy resin and their addition amounts on the tensile properties, bonding properties, and hardness of silane modified polyether adhesive (MS adhesive), four types of epoxy resin, namely bisphenol A type, bisphenol F type, phenolic epoxy, and flexible epoxy, were added to the basic formula of MS adhesive by the method of physical blending at mass fractions of 0%, 5%, 10%, and 15%, respectively in this study. The effects of different types of epoxy resin on the strength, modulus, and polar substrate bonding of MS adhesive were studied. The research results showed that rigid epoxy resin could significantly improve the tensile strength, modulus, and hardness of MS adhesive, but reduce the elongation at break. Flexible epoxy resin played a role in plasticizing and toughening. This study systematically revealed the structure-activity relationship between epoxy resin structure and MS adhesive properties, enriching the understanding of compatibility and reinforcement mechanisms in multiphase systems. The innovation lay in the first comparison of the modification effects of four typical epoxy resins in MS adhesive, clarifying the differential mechanism between rigid reinforcement and flexible toughening. This study provided a theoretical basis and formulation scheme for the development of high strength, high toughness, and high bonding MS adhesive products, which had broad application prospects in fields such as prefabricated construction and automotive manufacturing.
【Keywords】MS adhesive; bisphenol A type; bisphenol F type; phenolic epoxy; flexible epoxy
Material Science
Preparation of lignin modified by organic acid deep eutectic solvents (DES) and lignin-based phenolic resin
Zhuang Junping, Wang Zishuai
(School of Light Industry and Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China)
【Abstract】Lignin, due to its phenol-like structure, can partially replace phenol in the preparation of lignin-based phenolic resin adhesive. Deep eutectic solvent (DES), as a new type of lignin functionalization reaction medium, can change the reactivity of lignin by introducing new functional groups or increasing or decreasing the content of existing functional groups. Coniferous wood sulfate lignin (SKL) was used as raw material in this study, it was modified with different types of organic acids DES to prepare DES modified lignin, and then, deep eutectic solvent modified lignin-based phenolic resin (DLPF) adhesive was prepared. The effects of organic acid types on the content and molecular weight changes of lignin groups, as well as the structural changes of lignin after different DES modifications on the bonding performance of DLPF adhesive were investigated. The research results showed that: ⑴ After SKL was treated with mixed organic acid DES, the phenolic hydroxyl content of lignin could be increased, and the methoxy content could be reduced, thereby enhancing the reactivity of lignin. ⑵ DES modified lignin with different types of organic acids partially replaced phenol to prepare LPF, which was beneficial for improving the performance of corresponding DLPF adhesive. ⑶ After modification with organic acid DES, the relative molecular weight of lignin was significantly reduced, and the polydispersity index was also significantly reduced, which helped to improve the mechanical properties of phenolic resin adhesive. ⑷ Infrared spectroscopy analysis showed that DES modification with organic acids promoted the breaking of ether bonds in lignin structure, resulting in the formation of small molecule phenolic compounds and an increase in reactive sites. ⑸ Thermal stability analysis showed that through appropriate DES modification activation, lignin could maintain the thermal stability of the resin under high substitution rate conditions. ⑹ This study provided a feasible path for the high-value utilization of lignin and the development of green and environmentally friendly phenolic resin adhesive.
【Keywords】lignin; deep eutectic solvent (DES); organic acid; phenolic resin; adhesive; bonding strength