Scientific Research Report
Study on the relationship between viscoelasticity and bonding properties of acrylate pressure sensitive adhesive
Xue Shuangle, Zhang Xugang, Xue Gang, Zhang Bin, Sun Mingming, Li Jianhui
（Institute of Petrochemistry Heilongjiang Academy of Sciences, Harbin 150040, Heilongjiang, China）
【Abstract】Firstly, the effects of the ratio of functional monomer acrylic acid (AA)/hydroxypropyl methacrylate (HPMA) on the performance of pressure sensitive adhesive were studied, and it was concluded that the performance of pressure sensitive adhesive was optimal when m(AA)∶m(HPMA)=6∶2. Then based on pressure sensitive adhesive solution with m(AA)∶m(HPMA)=6∶2, acrylate pressure sensitive adhesive with different degrees of crosslinking using aluminum acetylacetonate (AlACA) as crosslinking agent was prepared, and the relationship between its viscoelasticity and bonding properties was investigated. The research results showed that at normal temperature, the storage modulus of pressure sensitive adhesive was about 40-60 kPa, tanδ was in the range of 0.5-0.7, the deformation rate was about 3%-8% and the deformation recovery rate was more than 80%, and the relaxation time was about 110-600 s, then pressure sensitive adhesive with excellent comprehensive performance was obtained.
【Keywords】acrylate pressure sensitive adhesive; crosslinking; viscoelasticity; bonding property
Preparation of polyurethane modified acrylate monomer and performance of its vinyl acetate-acrylate copolymer emulsion adhesive
Guan Tao, Chen Changzhu, Li Yuanlu, Qiu Yuanbin, Lin Haifeng, Pan Hanjie
(Key Laboratory of Fujian Architectural Coatings Enterprise, SKSHU Paint Co., Ltd., Putian 351100, Fujian, China)
【Abstract】A kind of polyurethane modified acrylate (PUA) hybrid monomer material was prepared using hydroxyethyl acrylate (HEA), toluene diisocyanate (TDI), and 2-ethylhexanol as raw materials. The water resistance, wet shear strength and dry bonding strength of vinyl acetate-acrylate latex film prepared by PUA monomer and conventional monomers such as acrylic acid (AA), acrylamide (AM), hydroxypropyl acrylate (HPA), vinyl acetate (VAc), 2-ethylhexyl acrylate (2-EHA), which involved in the copolymerization of vinyl acetate-butyl acetate mixed monomers, were compared. The research results showed that the vinyl acetate-acrylate emulsion film prepared by copolymerization of monomers with strong hydrophilicity and high polarity, such as AA, AM and HPA, had good dry strength, but poor water resistance and wet strength. The water resistance of the emulsion film prepared by copolymerization of VAc, 2-EHA and other monomers was relatively good, but the dry strength and wet film strength were poor. Compared with the conventional monomers mentioned above, the vinyl acetate-butyl acetate emulsion film prepared by copolymerization of PUA monomer had good balance of wet shear strength on birch block and dry strength on birch block and aluminum strip substrate, which was expected to be used as a new functional monomer for the preparation of high-performance polyvinyl acetate emulsion adhesive.
【Keywords】PUA hybrid monomer; emulsion adhesive; polyvinyl acetate; water resistance
Development and Application
Study on failure mode of composite bonded aluminum alloy structure based on acoustic emission detection
Dai Jingtao1, Liu Haodong1, Zhao Peizhong1, Su Hongbo1, Fu Yafeng2, Qu Lifeng3
（1.Naval Aviation University Qingdao Branch, Qingdao 266041, Shandong, China; 2.No.91286 Unit, People’s Liberation Army of China, Qingdao 266003, Shandong, China; 3.Military Representative Office in No.167 Factory, Chengdu 610000, Sichuan, China)
【Abstract】The composite patch was prepared by wet laying method, and the damaged aluminum alloy specimen was repaired by bonding with the patch. Then, based on the acoustic emission detection method, the failure process of the specimens in the tensile test was dynamically monitored, and the performance and failure mode of the composite bonding repair of aluminum alloy components were analyzed and evaluated. The research results showed that, the main reason for the different failure modes was that the bonding strength between the composite patch and the damaged aluminum plate was different from the tensile failure strength of the patch. The main failure modes of the specimen could be improved from interface failure to mixed failure and patch failure by applying coupling agent or heating and curing under pressure. The tensile strength of the specimen with mixed failure and patch failure was higher than that with interface failure.
【Keywords】composite material; aluminum alloy; acoustic emission detection; tensile strength; failure mode
Study on preparation and properties of hot melt pressure sensitive adhesive for reefer container
Dai Fei, Wei Guocai, Wei Jingjing
[Kangda New Materials (Group) Co., Ltd., Shanghai 201419, China]
【Abstract】In order to prepare hot melt pressure sensitive adhesive with excellent performance for reefer container, the formula components and properties of hot melt pressure sensitive adhesive were studied. By studying the relevant factors affecting the adhesive performance, such as viscosity, bonding strength, softening point and other physical properties, the type and content of three kinds of elastomer, four kinds of tackifying resin and three kinds of plasticizer used in the formulation were selected, in order to find the optimum formula composition. The research results showed that in the formula, when the tackifying resin was C5 hydro petroleum resin with a content of 40%, the plasticizer was naphthenic oil with a content of 20%, and the elastomer was a mixture of SIS elastomer with a total content of 33%, the prepared hot melt pressure sensitive adhesive for reefer container had good comprehensive performance. In addition, from the DSC curve of hot melt pressure sensitive adhesive in this paper, it could be seen that the hot melt pressure sensitive adhesive did not exhibit obvious two-phase glass transition temperature.
【Keywords】hot melt pressure sensitive adhesive; elastomer; tackifying resin; plasticizer; reefer container
Special Topics and Review
Research progress in microelectronic packaging materials and their reliability
Wang Juanjuan1, Yu Yingfeng1,2, Jing Hua2,3, Liu Licheng2,3, Xu Zixi2,3
(1.State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular
Science, Fudan University, Shanghai 200433, China; 2. Natong Kernel Co., Ltd., Nantong 226007, Jiangsu Province, China; 3. Shanghai Sci-bon Technology Co., Ltd., Shanghai 201818, China )
【Abstract】With the development of microelectronic industry, a variety of packaging technologies are emerging, which put forward higher requirements for the internal stress, thermal conductivity and electrical properties of packaging materials. In this paper, the main materials for polymer microelectronic packaging, including epoxy resin, silicone, and polyimide were introduced. Due to the development of lead-free packaging and the need for heat dissipation of high power, conductive adhesive and thermal interface materials had become the more popular materials in the packaging research. According to the use environment of the product, the reliability of packaging could be evaluated by accelerated test (temperature cycle, high accelerated stress test, fatigue test, etc.). In order to explore the causes of packaging failure, it was necessary to carry out failure analysis for the product. In this paper, the commonly used failure analysis technology was introduced, the failure analysis of the underfill adhesive of flip chip was specifically described, and the performance requirements for the underfill material were put forward according to the failure reasons. The cold/thermal shock and hygrothermal stability of packaging materials were important factors affecting the reliability, moisture could lead to package “popcorn effect”, electrochemical migration and other consequences, which would make the device fail. For this reason, in this paper, the effect and diffusion mechanism of moisture on semiconductor devices were explored, and the factors affecting the water absorption performance of materials (such as polarity, free volume, material micro-phase separation, etc.) were reviewed. Finally, the future development of microelectronic packaging materials was also prospected.
【Keywords】electronic packaging; conductive adhesive; thermal conductive adhesive; reliability analysis; failure analysis; damp-heat aging
Research progress of epoxy resin-based underfill with thermal conductivity
Li Yinle, Sun Zhaoning, Pang Chao, Zhang Zhixin, Zhao Zhenbo, Zhao Hao
(The Fifth Electronic Research Institute of Ministry of Industry and Information Technology, Guangzhou 511370, Guangdong, China)
【Abstract】Underfill, as an important electronic adhesive for integrated circuit packaging, is used in advanced packaging such as 2.5D and 3D packaging, to alleviate the problem of stress concentration caused by the mismatch of thermal expansion coefficients among different materials in chip packaging, thus improving the reliability of device packaging. Among all kinds of underfill materials, epoxy resin-based underfill is the most commonly used and the most commercially mature product. However, the widely used capillary epoxy underfill material has a low thermal conductivity, which cannot meet the growing heat dissipation requirements of the next generation of advanced packaging chips with higher power density. Although many strategies have been proposed to improve the thermal conductivity of epoxy resin, its application as underfill material with complex performance requirements is still difficult, and optimizing the thermal-electrical-mechanical properties of the underfill for flip chip packaging is still a huge challenge. In this paper, the latest progress of thermal conductive epoxy resin-based underfill to meet the key heat dissipation requirements was reviewed. At the same time, it provided ideas for the design of electronic packaging of high power density electronic devices with high thermal conductivity and high reliability of underfill materials.
【Keywords】underfill; epoxy resin; thermal conductivity
Progress in modification of styrene-isoprene-styrene (SIS) elastomer
Feng Daoshuo1, Wang Jie1, Wang Jinchang2, Li Huiyang2, Zhang Wenwen2, Wang Bin2, Cui Lirong2, Huang Haofei1, Rong Weifeng1, Cui Guangjun2
(1.School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, Shandong, China; 2.Zibo Luhua Hongjin New Material Group Co., Ltd., Zibo 255411, Shandong, China)
【Abstract】Various modification methods of thermoplastic elastomer SIS were briefly introduced, and the advantages, disadvantages and application of each modification method were summarized. The modification of SIS mainly included the introduction of polar monomers and post-polymerization modification. The former one was the introduction of monomers with special functions in the preparation of SIS to achieve the purpose of modification. The latter one was mainly introduced from both physical and chemical aspects. In the physical aspect, the mechanical blending method was mainly adopted, according to the modification requirements of blending and mixing materials with corresponding demanding functions to complete the modification. The chemical modification methods mainly included photochemical reaction, hydroxylation, epoxidation, sulfonation and free radical grafting modification, and etc. In this paper, the modification research progress and latest application of thermoplastic elastomer SIS were systematically reviewed, and the future outlook of SIS was summarized.
【Keywords】thermoplastic elastomer; SIS; modification
Progress in polyurethane recycling
Zhao Liang, Zhang Lijuan, Zhu Yun, Wang Guiyou
(School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China)
【Abstract】Polyurethane (PU), as the sixth most commonly used polymer in the world, is widely used in the fields of furniture, architecture, automotive, aerospace and medical health. With the depletion of petroleum resources and the deterioration of ecological environment, the recycling of polyurethane has become an important problem to be solved urgently. As the most primitive recycling method, the way of landfill not only occupies land and pollutes water and soil resources, but also consumes a lot of manpower and material resources in the cost of recycling. Incineration to recover heat is also a common method for recycling polyurethane materials, but polyurethane is very easy to produce toxic and harmful substances during the incineration process. Physical recycling has large-scale application in actual recycling work, but it requires the condition of high temperature and pressure during the recycling process, which results in great restrictions on this recycling method. At present, a large number of studies have shown that chemical recycling is the most promising means of polyurethane material recycling. In this paper, a variety of chemical recycling processes including alcoholysis, hydrolysis, aminolysis, pyrolysis, phosphorylation and biodegradation, as well as the latest research progress were discussed in details.
【Keywords】polyurethane recycling; landfill; physical recycling; chemical recycling