Special Topics Review
Research progress on the application of optically clear adhesive in touch screen
Wang Mingyang1, Li Minghao1, Jiang Baian1, Xu Yichen1, Wang Hong2, Zhao Biao1
(1.College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China; 2. Beijing Dwin Technology Co., Ltd., Beijing 100089, China)
【Abstract】As one of the simplest ways of human-computer interaction, touch screen is rapidly replacing the traditional electronic display in recent years. Optically clear adhesive(OCA) is a transparent optical pressure-sensitive adhesive with high light transmittance and considerable adhesion, which is widely used to bond different layers of touch screen. OCA can effectively enhance the optical effect, touch responsiveness, and mechanical reliability of touch screen, reduce screen glare, and provide better visual experience for users. In this paper, the characteristics, classification, curing methods, bonding mechanisms, and technical progress of OCA were systematically introduced, and its future development prospects were also discussed.
【Keywords】optically clear adhesive; classification; curing method; bonding mechanism; research progress
Research progress of bio-based polymer modified asphalt
Tian Peijun1, Kan Shiyun2, Zhang Zengping2, Qian Jianhang3, Yang Yang1, Xia Jingjie1, Liu Hao2
（1. Ningbo Dongxing Asphalt Products Co., Ltd., Ningbo 315000, Zhejiang, China; 2. Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang’an University, Xi’an 710064, Shaanxi, China; 3.Chang’an Dublin International College of Transportation, Chang’an University, Xi’an 710018, Shaanxi, China）
【Abstract】With the vigorous development of China’s road and bridge construction, modified asphalt gradually occupies the application market, and adding high polymers such as epoxy resin, polyurethane, phenolic resin to asphalt can obtain high-performance modified asphalt or asphalt mixture. In order to reduce the consumption of non-renewable resources and facilitate the sustainable development of road engineering, bio-based raw materials are gradually replacing petroleum-based raw materials. In this paper, the raw materials and research progress of resin modified asphalt (bio-based polyurethane, bio-based phenolic resin), bio-based rubber modified asphalt, bio-based natural elastomer modified asphalt, and bio-based composite modified asphalt were mainly reviewed and summarized, and the latest research results of bio-based modifiers (plant oil, plant phenols, lignin, rosin, itaconic acid, etc.) were also shared. The current problems of bio-based polymer modified asphalt were proposed, and finally, the future development prospects were discussed.
【Keywords】modified asphalt; bio-based polymer; modification mechanism
Research and application progress of PVC weld seam sealant for car body coating
Yu Hu, Yang Shiyong, Meng Hui, Lu Zhuo, Duan Chenjie
(Jinan Hansiman Times Technology Co., Ltd., Ji’nan 250031, Shandong, China)
【Abstract】The development of the automotive industry has put forward higher requirements for body sealing, and PVC weld seam sealant, as one of the most important types of coating adhesive, has received increasing attention in its research. In this paper, the public reports and industry research progress on the formulation and construction technology of PVC weld seam sealant in China in recent years were summarized, mainly including the mechanical properties, construction properties, environmental performance, construction technology, and special vehicle requirements of PVC weld seam sealant. Finally, a summary and outlook were provided.
【Keywords】PVC weld seam sealant; car body sealing; construction technology; coating
Research Report
Study on bonding properties of cellulose-based epoxy resin and its wood adhesive
Zhang Tongtong1, Wang Fang1, Zhou Zi2, Zhu Xinbao1,2
(1. College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, Jiangsu, China; 2. Anhui Xinyuan Technology Co., Ltd., Huangshan 245900, Anhui, China)
【Abstract】Liquid cellulose-based epoxy resin (PHECEP) was synthesized by grafting liquefaction reaction with ethylene oxide (EO) using alkali activated cellulose as raw material. Then, using E-51 as the matrix resin, amine T31 as the curing agent, silica powder, silane coupling agent KH-560 and PHECEP as modifiers, cellulose-based epoxy resin adhesive was prepared, and its mechanical properties, thermal properties, and chemical resistance were tested. The research results showed that, when the addition amount of PHECEP was 20%, the impact strength increased from 2.9 kJ/m2 to 50.9 kJ/m2. When the addition amount of PHECEP was 5%, the tensile shear strength of cellulose-based adhesive cured for 7 d at room temperature was 171.1% higher than that of pure E-51. After adding PHECEP, the actual tensile shear strength was higher than the tested strength, and the tolerance was better in small molecule solvents. Through the comprehensive evaluation of mechanical properties, wet/dry bonding strength, thermal stability, and chemical resistance of PHECEP/E-51 materials, the relatively optimal formula of wood adhesive was obtained as follows: 5% PHECEP (relative to the mass of E-51), 1% KH-560, 60% silica powder, and 18% T31 curing agent (relative to the total mass of PHECEP and E-51, respectively).
【Keywords】cellulose; cellulose-based epoxy resin; bisphenol A type epoxy resin; wood adhesive; bonding property
Construction of finite element numerical calculation model for interfacial bonding strength evaluation of composite elastomer
Yang Min, Xu Yonglun, Wang Shuting, Pang Yunsong, Ren Linlin, Zeng Xiaoliang, Sun Rong
（Shenzhen Institute of Advanced Electronic Materials, Shenzhen 518100, Guangdong, China）
【Abstract】Based on silicone gel composite elastomer, finite element numerical calculation model was constructed to calculate the interfacial bonding strength. This model included cohesive force and mechanical model of hyper elastic materials with Mullins effect, which respectively described the energy loss at the interface of composite elastomers during peeling and the energy loss during deformation of surrounding materials. Abaqus could be used to directly implement examples, and the relevant calculation parameters required for the examples could be obtained through corresponding material mechanics characterization. Due to the similarity in the trend, amplitude, and interval of the data curve with the experimental results, it proved that the constructed finite element numerical model had a certain degree of accuracy. This study provided a new approach for predicting material properties through finite element numerical calculations, which replaced the complex experimental characterization methods.
【Keywords】composite elastomer; interfacial bonding strength; finite element numerical calculation; cohesive force; Mullins effect
Study on catalytic curing of benzoxazine-based organosilicone adhesive
Wang Yuanrong, Huang Tingting, Fu Pengxiao, Xiao Ruizhi, Jiang Zhenhao, Yang Zhihui, Lu Haifeng
(School of Chemistry and Chemical Engineering, Shandong University, Key Laboratory of Special Functional Aggregate Materials, Ministry of Education, Ji’nan 250100, Shandong, China )
【Abstract】As a thermosetting resin with excellent performance, benzoxazine has been widely used in aerospace, electronics and electrical fields. However, it also shows the disadvantages of high curing temperature, poor processability, and high brittleness. Organosilicone compounds have attracted the attention of researchers because of their excellent toughness and low surface tension, which make them easier to spread on the material due to their low surface tension. Based on this, the benzoxazine-based organosilicone adhesive was studied in this paper. By using different proportions of organic acids (such as p-toluenesulfonic acid, glacial acetic acid, phosphoric acid) or organic bases (such as aniline, ethanolamine, 2-methyl-1,5-pentanediamine) for catalysis, the bonding strength of the adhesive on iron sheet or special plate under different catalytic conditions was compared. The research results showed that, when p-toluenesulfonic acid or phosphoric acid was used to catalyze the bonding of iron sheet, better catalytic effects were achieved at 120 ℃ or 100 ℃ curing processes than the original body, with values of 4.68 and 4.32 MPa, respectively. When organic base catalysts were used to catalyze the bonding of iron sheet or special plate, 2-methyl-1,5-pentanediamine had been proven to be the optimal catalyst. When the mass ratio of m(2-methyl-1,5-pentanediamine)∶m(adhesive) was 1∶9 or 1∶18, respectively, better bonding effects were achieved on iron sheet or special plate, which confirmed that this catalyst had excellent catalytic effect. The use of 2-methyl-1,5-pentanediamine could effectively reduce the ring opening curing temperature and improved the bonding strength (reaching 9.92 MPa at 120 ℃), which provided an effective approach for achieving low-temperature curing of benzoxazine-based organosilicone adhesive.
【Keywords】benzoxazine; organosilicone; adhesive; catalyst
Process and Application
Research on the properties of weather-resistance polyolefin adhesive film
Tang Fangcheng, Du Zhuang, Deng Zhiye, Wang Jiasheng, Yang Tao
(Guangzhou Lushan New Materials Co., Ltd., Guangzhou 510530, Guangdong, China)
【Abstract】Modified polyolefin materials with weather-resistance and bonding properties were prepared separately by using polyolefin modification technology, and then these modified polyolefin materials were integrated through molding process of co-extrusion film blowing to prepare functional polyolefin adhesive film with both weather-resistance and bonding properties. The processing, weather resistance, and bonding properties of adhesive film were further evaluated and studied. The research results showed that, when the thickness ratio of the inner, middle, and outer layers of adhesive film was about 28∶31∶41, the three materials had good processing properties such as cutting, plasticizing, and blowing to form a film. The mechanical properties of adhesive film in both horizontal and vertical directions were good, and it had good bonding effects on steel plate, aluminum plate, and galvanized plate. When used as the coating of metal surface, it had a certain degree of acid and alkali corrosion resistance, and the adhesive interface between the adhesive film and the metal was stable and reliable. It had excellent weather resistance and heat and oxygen aging resistance, which could be used as the coating of metal composite materials with weather resistance and bonding functions.
【Keywords】polyolefin; adhesive film; peeling strength; aging
Research on bonding process of epoxy adhesive film for edge connection of cockpit transparent parts
Li Yan
(AVIC Manufacturing Technology Institute, Beijing 100024, China)
【Abstract】The curing behavior of J-351 epoxy adhesive film was studied by using non isothermal differential scanning calorimetry method, and the theoretical curing temperature range of J-351 epoxy adhesive film was calculated by using T-β extrapolation method. Furthermore, experimental verification was conducted on the performance parameters related to curing temperature, surface treatment, and pressure method during the use of epoxy adhesive film for edge connection of cockpit transparent parts, and the optimal bonding process was determined. By conducting fatigue tests on typical structural components, the feasibility of the process was verified, which provided key process parameters for edge bonding of large-sized cockpit transparent parts. The research results showed that, ⑴ The curing reaction of J-351 epoxy adhesive film was a single exothermic peak. According to T-β extrapolation method, it showed that the theoretical reaction temperature range of J-351 epoxy adhesive film was 70.92-127.21 ℃. ⑵ When the curing temperature was 85 ℃ and the curing time was 6 h, the shear strength of adhesive film could meet the requirements for edge connection of cockpit transparent parts. Adding pre-curing steps could effectively improve the wettability between adhesive film and organic glass or polyester ribbon. ⑶ The best effect was achieved by using 320 grit sandpaper for polishing and under vacuum pressure. ⑷ The relatively optimal process conditions were as follows: the surface of the organic glass was polished with 320 grit sandpaper, pre-cured at 70 ℃ for 1 h, cured at 85 ℃ for 6 h, and subject to vacuum bag pressure of 0.1 MPa. The shear strength of the edge connection adhesive component produced was about 234 kN/m, the fatigue cycle number of typical structural components could reach 150 000 times, and the fatigue ultimate load could reach 8.352 kN, which could meet the requirements for edge connection of cockpit transparent parts.
【Keywords】curing temperature; surface treatment; pressurization method; fatigue
Material Science
Preparation and properties of epoxy-phenolic aldehyde-bismaleimide ternary blend
Wang Xiaolei1, Dai Shengwei1, Zhang Yousheng2, Yang Changxu1, Han Shujun1, Qi Yuexin1, Liu Jingang1
(1.Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083, China; 2. Zhejiang Jameen New Material Co., Ltd., Jiaxing 314011, Zhejiang, China)
【Abstract】A ternary resin blend (BPE) and its cured product were prepared by melt blending 4,4'-diphenylmethane bismaleimide (BMI) with polyaromatic ring phenolic resin, polyaromatic ring epoxy resin (NC3000), and promoter 2-phenyl-4-methyl-5-hydroxymethylimidazole(2P4MHZ), and their properties were evaluated. The research results showed that the BPE ternary resin blend only exhibited one curing behavior, which could be fully cured in the existing epoxy molding compound (EMC) preparation process. Structural characteristic analysis showed that the BPE ternary resin blend had been successfully prepared, and mutual crosslinking reactions had occurred between the ternary resins. The crystalline state and rheological analysis of the ternary resin blend showed that the ternary resin blend exhibited obvious amorphous characteristics. With the increase of temperature, the melt viscosity began to decline, reaching the lowest value at 140-160 ℃, and then rapidly increased several orders of magnitude with gelation, and there existed a certain processing window at 110-160 ℃, which was beneficial to the preparation of EMC. With the increase of BMI content, the heat resistance stability of the cured ternary resin was also constantly increasing, and the thermal decomposition temperature of 10% exceeded 430 ℃. In addition, the introduction of BMI also prolonged the gel time of the blend, and destroyed the curing and crosslinking of the epoxy/phenolic aldehyde resin system, resulting in increased weight loss during high-temperature thermal aging.
【Keywords】bismaleimide; epoxy resin; epoxy molding compound (EMC); thermal stability
Experimental and simulation studies on the wave-absorbing performance of epoxy resin-filled composite honeycomb sandwich structure
Zhang Wei1, Han Yangyang2, Huang Shaoliang1, Liu Yaqing1, Zhao Guizhe1, Liang Chaobo1
(1.College of Materials Science and Engineering, North University of China, Taiyuan 030051, Shanxi China; 2.No.33 Research Institute of China Electronics Technology Group Corporation, Taiyuan 030032, Shanxi China)
【Abstract】The composite honeycomb sandwich structure (CHSS) filled with ferrosoferric oxide@reduced graphene oxide (Fe3O4@rGO) aerogel/epoxy resin was designed. The Fe3O4@rGO particles were characterized by Raman spectroscopy and X-ray photoelectron spectroscopy, and their electromagnetic parameters and wave-absorbing performance were analyzed. The research results showed that Fe3O4@rGO was successfully prepared and Fe3O4 was well dispersed in the aerogel. The conductive loss of Fe3O4@rGO to electromagnetic waves as well as the magnetic loss provided good microwave absorption performance for the material, and the effective wave-absorbing bandwidth of CHSS showed a tendency to increase first and then decrease as the thickness of the Fe3O4@rGO aerogel/epoxy resin layer increased. When the thickness of Fe3O4@rGO aerogel/epoxy resin layer in CHSS was 2.5 mm, the effective absorption bandwidth reached the maximum, the thickness of the CHSS with the best performance was 7.8 mm, the effective absorption bandwidth reached 7.09 GHz, and the maximum reflection loss (RL) value reached -17.76 dB. Comprehensively, it showed that a composite honeycomb sandwich material had been prepared in this study, and the desired wave-absorbing performance could be achieved by using epoxy resin to backfill and encapsulating the aramid honeycomb.
【Keywords】aerogel; epoxy resin; aramid honeycomb; wave-absorbing performance