Special Topics Review

Status and development trend of China adhesive and tape industry

Yang Xu

(China Adhesives and Tape Industry Association, Beijing  100028, China)

【Abstract】Based on the updated industry statistics and policies, the current situation and development trends of China's adhesive and tape industry were analyzed systematically and elaborated comprehensively in this article from four aspects of industry market overview, economic operation characteristics, problems and challenges faced by the industry, and industry development prospects.

【Keywords】adhesive; tape; industry status; development trend

Research progress of modified waterborne polyurethane adhesive for automotive interior

Fan Xiuming, Jin Xin, Jiang Hui, Jiang Hongyu

（Jilin Agricultural Science and Technology University, Jilin  132101, Jilin, China）

【Abstract】The basic overview and preparation methods of polyurethane(PU) adhesive and waterborne polyurethane (WPU) adhesive in the automotive interior field were elaborated systematically in this article, with a focus on the mainstream modification research of WPU adhesive. By analyzing in details the action mechanism of various modification methods such as epoxy resin, silicone, organic fluorine, and nanomaterials on WPU adhesive, the structural characteristics and performance evolution of the modified products were deeply explored. On this basis, the future development trend of WPU adhesive was discussed.

【Keywords】automotive interior;waterborne polyurethane;adhesive;modification

Research Report

Preparation of LED-responsive photo alkali production system and its application in thiol-epoxy adhesive

Zhu Weite¹, Li Zhiquan^1,2,Liu Xiaoxuan^1,2

(1.School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China;2.Guangdong Laboratory of Chemistry and Fine Chemical Industry Jieyang Center, Jieyang 522000, Guangdong, China)

【Abstract】In response to the problem of short absorption wavelength and difficulty in matching with LED light sources, reduced amidine (PL-DBN) was used as a photo alkali generator in this paper, and combined it with three photosensitizers, namely isopropylthioanthraquinone (ITX), 2-ethylanthraquinone (2-EAQ), and 9,10-dibutoxyanthracene (DBA), a type of LED-responsive photo alkali system was prepared, and its application in thiol-epoxy adhesive was studied systematically. The research results showed that, ⑴ The PL-DBN/2-EAQ system had the smallest electron transfer Gibbs free energy (-3.227 eV) and the highest photosensitization efficiency. ⑵ Under 365 nm LED irradiation, the pH of PL-DBN/2-EAQ system could rapidly increase from 7.65 to 11.08, indicating its excellent alkali production efficiency. ⑶ With the extension of light exposure time (0-15 min), the starting temperature of thiol-epoxy polymerization could be reduced from 80.3 ℃ to 56.2 ℃, indicating that the photo alkali production system effectively reduced the reaction energy barrier. ⑷ The conversion rates of thiol and epoxy functional groups could ultimately reach 95% and 100%, respectively. The sample exposed to light for 15 minutes could be completely cured after being placed at 60 ℃ for 1 hour, with a bonding strength of 3.5 MPa, demonstrating its promising application prospects in precision bonding fields such as flexible electronic packaging and optical device assembly.

【Keywords】photo alkali production agent; photosensitizer; photothermal dual curing; thiol-epoxy polymerization

Research on development and performance of novel mAP-E multi-functional epoxy adhesive

Zhang Yi, Yu Xinhai

(College of Chemistry and Chemical Engineering, Donghua University, Shanghai  201620, China)

【Abstract】To overcome the technical bottleneck of high viscosity and poor toughness of traditional tetra functional group epoxy resin of tetraglycidyl diaminodiphenylmethane (TGDDM), a series of JmAP epoxy adhesive systems were established in this article by using m-aminophenol epoxy resin (mAP-E) as the matrix and adjusting its blending ratio with TGDDM. The key performance indicators such as the processability, thermal resistance, and mechanical properties of adhesive systems were investigated systematically. The research results showed that, ⑴ The mAP-E system could significantly reduce the viscosity of TGDDM, and the prepared JmAP adhesive had a lower viscosity, thus exhibiting good processability. ⑵ By analyzing the glass transition temperature (T_g) of the adhesive, it was found that in the JmAP series adhesive, the increase in TGDDM content caused the T_g value to shift towards higher temperatures. The glass transition temperature (T_g=164.7 ℃) of JmAP-5 increased by 16.3% compared to JmAP-0, demonstrating that the introduction of TGDDM significantly improved the heat resistance of the epoxy adhesive system. ⑶ By analyzing the mechanical properties, the JmAP series adhesive showed varying degrees of improvement in various mechanical properties at different temperatures with the increase of TGDDM ratio. Among them, JmAP-5 had relatively outstanding comprehensive mechanical properties at high temperature and excellent tensile shear properties at various temperatures. In the wide temperature range tensile shear performance test, JmAP-5 also showed the best comprehensive performance. ⑷ The analysis of water absorption performance showed that in the JmAP series adhesive system, the water absorption rate of each formula adhesive did not exceed 0.5%, demonstrating excellent durability and service life. ⑸ Electrical performance analysis showed that the JmAP series adhesive had good capacitance stability, with the fluctuation range within 0.15 pF, the relative dielectric constant difference of no more than 0.15, and the dielectric loss of less than 2%. Among them, JmAP-5 had the best electrical performance, with the capacitance of 5.37-5.53 pF at 1 000 Hz, the dielectric loss of less than 1.72%, and the relative dielectric constant between 4.14-4.22. This indicated that the JmAP-5 formulation had excellent electrical properties and could be applied in the field of electronic insulation.

【Keywords】mAP-E; TGDDM; multi-functional; epoxy adhesive; performance

Preparation and viscoelasticity study of high temperature resistance phosphorus-containing acrylate pressure sensitive adhesive

Xue Shuangle, Xue Gang, Zhang Xugang, Sun Mingming, Yuan Zhigang, Xing Wenxu, Li Jianhui, Zhang Bin

(Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin  150040, Heilongjiang, China )

【Abstract】Using 2-hydroxyethyl acrylate phosphate (HEMAP) and acrylic monomer as raw materials, acrylate phosphate pressure sensitive adhesive was prepared by copolymerization reaction. The effects of different contents of HEMAP on the bonding performance and viscoelastic behavior of pressure sensitive adhesive were studied emphatically. The research results showed that, ⑴ As the content of HEMAP increased, the stretching vibration peak of the P=O double bond at 1 220 cm^-1 became more pronounced, and the glass transition temperature (T_g) of pressure sensitive adhesive also slightly increased. ⑵ With the increase of HEMAP content, the initial tack of pressure sensitive adhesive gradually decreased, the holding time and peel strength increased, and the high temperature resistance of pressure sensitive adhesive improved. ⑶ The storage modulus (G') and loss modulus (G'') of pressure sensitive adhesive increased with the increase of HEMAP content at the same temperature. At different temperatures ranging from 25 to 160 ℃, with the increase of HEMAP content, the temperature dependence of pressure sensitive adhesive decreased, and the temperature resistance improved. The HEMAP content affected the rheological and bonding properties of pressure sensitive adhesive. ⑷ With the increase of HEMAP content, the maximum deformation of pressure sensitive adhesive decreased, the recovery rate increased, and the creep resistance was enhanced. ⑸ As the scanning frequency increased, the G' and G'' of pressure sensitive adhesive increased. However, with the increase of HEMAP content, the entanglement and cross-linking density of polymer chains further increased, and the relaxation time of chain segments became shorter, resulting in higher G' and G'' of pressure sensitive adhesive in different frequency ranges. PSA-P0.75 had high peel strength, but its initial tack was poor.

【Keywords】acrylate phosphate pressure sensitive adhesive; viscoelasticity; high temperature resistance

Process and Application

Research on bonding of titanium alloy and composite material with an epoxy adhesive film

Yang Haidong, Wang Dezhi, Li Hongfeng, Xiao Wanbao, Zhao Liwei, Feng Hao, Zheng Shuai, Qu Chunyan

(Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin  150040, Heilongjiang, China)

【Abstract】Using epoxy resin, interfacial modifier, toughening agent, and curing agent as raw materials, a new type of epoxy adhesive film was prepared in this paper by a combination of melting and mechanical blending methods. The curing process, heat resistance, micromorphology, and mechanical properties of the film were subsequently investigated. The research results showed that, ⑴ The curing reaction kinetics of the modified resin were investigated by using the DSC method. Through linear fitting, the reaction activation energy E_a was determined to be 68.17 kJ/mol and the reaction order n was 0.92, indicating that the curing reaction of the matrix resin was a complex curing process. ⑵ The glass transition temperatures of adhesive film were tested by using the tanδ method and found to be 194 ℃ and 223 ℃, respectively. The adhesive film exhibited excellent thermal and mechanical properties. The TG curve showed that the temperature at which the cured adhesive film lost 5% of its mass was approximately 351 ℃, indicating that the adhesive film had excellent high-temperature resistance. ⑶ At 23 ℃, the shear strength of titanium alloy and composite material, as well as aluminum alloy and aluminum alloy, were all above 40 MPa, with a small difference. At 121 ℃ and 177 ℃, the shear strength of titanium alloy and composite material was significantly lower than that of aluminum alloy and aluminum alloy. Therefore, the bonding strength of titanium alloy and composite material under high temperature conditions (121 ℃ and 177 ℃) depended on the bulk strength of the composite material. ⑷ Under the testing conditions of room temperature (23 ℃) and high temperature (177 ℃), the shear strength of adhesive film on titanium alloy and composite specimens was very close under two curing processes (150 ℃/3 h and 180 ℃/3 h), and the failure mode was basically the same, indicating that the adhesive film had achieved complete curing under both curing conditions and achieved the same bonding effect. ⑸ The adhesive film had certain application prospects in the field of composite blades for aircraft engines.

【Keywords】titanium alloy; composite material; epoxy adhesive film; heat resistance; shear strength

Study on properties and application of an adhesive for multilayer thin-walled structure of helicopter

Hu Deyi¹, Tang Yihao^1,3, Zhang Yitao², Lu Minghui⁴, Liu Miao¹, Xiong Zhe¹, Chen Peijun¹, Cao Xiaohan⁵

（1. AVIC China Helicopter Research and Development Institute, Jingdezhen  333001,Jiangxi, China; 2. Aviation Military Representative Office of Army Equipment Department in Jingdezhen Area, Jingdezhen  333001, Jiangxi, China; 3. College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin  150001, Heilongjiang, China; 4. Key Laboratory of Nondestructive Testing Technology of Ministry of Education, Nanchang Hangkong University, Nanchang  330063, Jiangxi, China; 5. College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing  210016, Jiangsu, China）

【Abstract】A new adhesive(H-A&B) was used for effective bonding of multilayer thin-walled rubber metal structures for helicopters. This adhesive contained a bottom adhesive (H-A) and a surface adhesive (H-B) that had good bonding properties to both metal and rubber. The functional groups of the adhesive were analyzed using an infrared spectrometer, and the comprehensive properties of the adhesive H-A&B were analyzed through peel strength tests, scanning electron microscopy, and other methods. The research results indicated that: ⑴H-A and H-B had similar molecular structures inside, which made them more easily soluble and had lower interaction energy, resulting in better bonding effect.⑵A uniform, porous, and rough adhesive layer was formed on the surface of stainless steel or nickel metal after brushing with bottom adhesive H-A, and then covered with surface adhesive H-B to form a complete adhesive layer, significantly improving the surface morphology. Energy spectrum analysis showed that after brushing the adhesive layer, the surface elements of the metal changed to mainly C and O, indicating the formation of an organic adhesive layer with good compatibility with rubber, which helped to improve the interfacial bonding performance.⑶The bonding mechanical properties of the new adhesive H-A&B were excellent, both exceeding the required indicators, and had good bonding performance for metal and rubber materials.⑷Through nondestructive testing, it could be seen that the typical samples made with the new adhesive H-A&B had fewer debonding defects and smaller sizes than those made with traditional adhesive, and all defect sizes were within the engineering allowable range. It had been proven that the new adhesive H-A&B outperformed traditional adhesive in terms of bonding performance and processability.

【Keywords】multilayer thin-walled structure; adhesive; peel strength; nondestructive testing

Preparation and performance study of high temperature resistant reactive polyurethane

hot melt adhesive for electronic products

Xiao Risheng, Ouyang Pengfei, Li Haiping

[Kangda New Materials (Group) Co., Ltd., Shanghai  201419, China]

【Abstract】High temperature resistant reactive polyurethane hot melt adhesive (PUR) was prepared by using polyether polyol, polyphenylene ether polyol, acrylic resin, crystalline polyester polyol, and 4,4'-diphenylmethane diisocyanate (MDI). The high temperature resistance of several polyols was compared, and the influence of the dosage of polyphenylene ether polyol, acrylic resin, and crystalline polyester polyol on the heat resistance of PUR was explored. The research results showed that, ⑴ The PUR prepared with polyphenylene ether polyol had the best heat resistance, with the shear strength of over 2 MPa at the high temperature of 110 ℃. ⑵ The higher the melting point and viscosity of crystalline polyester polyols, the greater the shear strength at high temperature, but the high temperature resistance was not improved. Overall, The type 7360 was the preferred solution for crystalline polyester materials in heat-resistant PUR application. ⑶ The larger the amount of polyphenylene ether polyol used, the higher the viscosity of PUR, the shorter the opening time, the greater the shear strength at high temperature, and the better the high-temperature aging resistance. The optimal addition amount of polyphenylene ether polyol was 15%. ⑷ The larger the amount of acrylic resin used, the higher the viscosity of PUR, and the higher the shear strength at high temperature. However, the retention rate of shear strength during high-temperature aging did not improve. Overall, the optimal addition amount of acrylic resin was 15%. ⑸ The comprehensive performance of high-temperature resistant PUR for electronic products was relatively optimal when reacting 15% polyphenylene ether polyol, 29.5% polyether polyol, 15% acrylic resin, 20% crystalline polyester polyol type 7360, and 0.5% DMDEE with 20% MDI. The viscosity of hot melt adhesive produced by this formula was 7 400 mPa·s at 110 ℃, with the shear strength of 11.51 MPa. The shear strength under high temperature condition was 2.42 MPa, and the shear strength retention rate reached 85% after high-temperature aging at 120 ℃.

【Keywords】reactive polyurethane hot melt adhesive; high temperature resistance; polyphenylene ether polyol; electronic adhesive

Rapid detection method for solid content of PVAc emulsion adhesive for cigarette

Zhang Fengfeng, Hou Yingying, Guo Zhongcheng, Song Xinhua,

Wu Hua, Wang Jikai, Xu Shijie, Sun Jingxian

（China Tobacco Shandong Industrial Co., Ltd., Ji'nan  250014, Shandong, China）

【Abstract】In order to effectively solve the contradiction between the detection speed and accuracy of PVAc emulsion adhesive for cigarette, improve the efficiency of testing the solid content of PVAc emulsion adhesive for cigarette, and achieve the goal of replacing national standard detection method and ensure data consistency, thermogravimetric-infrared analysis technology was used in this study to explore the changes in PVAc emulsion adhesive during the heating process. The research results showed that by using oven drying method to screen and determine the appropriate detection temperature and testing duration, the detection duration was significantly shortened from 180 min to 29 min. In the detection experiments conducted simultaneously with the national standard method and the new detection method, the deviation of the results obtained by the rapid detection method was less than 2%, which fully met the deviation requirements of the national standard method for the set value of solid content. This rapid detection method not only had good reproducibility of results, but also had high accuracy, effectively improving the detection efficiency for solid content of PVAc emulsion adhesive.

【Keywords】PVAc emulsion adhesive for cigarette; solid content; thermogravimetric-infrared analysis

Material Science

Preparation and performance study of fast curing low heat release epoxy filler

Xue Gang, Zhang Xugang, Xue Shuangle, Sun Mingming, Bai Xuefeng, Song Caiyu, Zhao Ming, Zhang Bin

(Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin  150040, Heilongjiang, China )

【Abstract】A low-density epoxy filler with fast curing and low heat release characteristics was successfully prepared by using epoxy resin as matrix, compound amine compounds as curing agent, and adding hollow glass microspheres with surface modification and combination optimization. The curing behavior, gel time, curing exothermic temperature, shear strength and compression properties of the filler were investigated in details. The research results showed that, ⑴ Curing agent C2 had high activity and could replace triethylenetetramine to lower the initial curing temperature and promote rapid curing. Its introduction significantly reduced the enthalpy change of heat release, reduced the amount of heat released, and avoided explosive aggregation. By adjusting the activity gradient of triethylenetetramine, C1 and C2, the curing kinetics could be optimized, and the exothermic peak could be effectively suppressed while the gel was fast. ⑵ The optimization of curing agent formulation significantly affected the gel properties and exothermic behavior of the system. The combination of triethylenetetramine/C1 was prone to explosive polymerization, and the introduction of C2 could achieve a balance between fast curing and uniformity, meeting construction requirements. ⑶ The increase in the amount of hollow glass microspheres added significantly reduced the system density, with a density of less than 0.70 g/cm³ at 35% addition, meeting specific application requirements. The mechanical properties of the composite material were good at this addition amount, with the shear strength reaching 15.3 MPa, the compressive strength exceeding 55 MPa, and the compressive modulus higher than 2 000 MPa. The comprehensive performance met the use requirements. ⑷ The filler had excellent fluidity and could completely fill the target area of the honeycomb. It was dense without bubble defects and firmly adhered to the honeycomb material without cracking. By using the process of injecting adhesive on one side and flowing out on the other side, the space around the inserts was filled and solidified for reinforcement. This filler could be widely used in aviation, transportation and other fields, especially for edge sealing and filling of aircraft honeycomb structures.

【Keywords】fast curing; low heat release; low density; epoxy; filler