• Composites Research
• /
• v.37 no.5
• /
• pp.393-401
• /
• 2024

Epoxy is a thermosetting polymer with excellent properties such as heat and chemical resistance, making them essential in various industrial fields including electronics. The performance of epoxy is highly dependent on the type of curing agent used. Among them, sulfonium-based latent curing agents are notable for their fast curing speed, high curing hardness, and specificity to certain temperatures, making them attractive for manufacturing anisotropic conductive films in electronic materials where single-component epoxy is required. However, sulfonium-based latent curing agents face challenges in industrial application due to issues with low yield and purity. This study optimized the synthesis conditions for benzyl and naphthyl-type sulfonium curing agents (B-Sul⁺SbF6^-, N-Sul⁺NCyF^-, N-Sul⁺NFSI^-). By adjusting reaction time, reaction temperature, and reactant ratios, yield was maximized, significantly reducing both reaction time and temperature. The three optimized curing agents were evaluated for their thermal and mechanical properties to assess curing behavior and storage stability. The results confirmed that stable curing performance was maintained even after mixing. This study aims to expand the industrial applicability of sulfonium curing agents.

• Journal of Adhesion and Interface
• /
• v.13 no.2
• /
• pp.53-57
• /
• 2012

A latent curing system was necessary for the anisotropic conducting film (ACF), and a fast reaction system was also necessary to fast production. In this study, the benzylsulfonium salts were synthesized and were used as latent curing initiators for epoxy resin. These benzylsulfonium compounds exhibited a long shelf life with epoxy resin. The curing behaviors of an epoxy resin with these sulfonium salts were investigated using differential scanning calorimetry (DSC), and the curing times were determined at $150^{\circ}C$ using an indentation method.

• The Korean Journal of Rheology
• /
• v.10 no.4
• /
• pp.227-233
• /
• 1998

The effects of 1 mol% N-benzylpyrazinium hexafluoroantimonate(BPH) as a thermal latent initiator and blend compositions composed of cycloaliphatic and DGEBA epoxies were investigated in the rheological properties and cure kinetics. Latent properties were performed by measurement of the conversion as a function of reaction time using isothermal DSC at $150^{\circ}C$ and $50^{\circ}C$ Rheological properties of the blend systems were investigated in terms of isothermal experiments using a rheometer. The gelation time was obtained from the evaluation of storage modulus (G'), loss modulus (G") and damping factor (tan$\delta$)). Cross-linking activation energy ($E_c$) was also determined from the Arrhenius equation based on gel time and curing temperature. As a result, the gel time and cross-linking activation energy increased with increasing DGEBA composition. The cure activation energies ($E_a$) were obtained by Kissinger method using dynamic DSC thermograms. In this work, the cure activation energy decreased with increasing CAE concentration, which might be resulted from the short repeat units, simple side-groups and viscosity of reaction media.edia.

• Polymer(Korea)
• /
• v.25 no.2
• /
• pp.168-176
• /
• 2001

The effect of novel N-crotyl-N,N-dimethyl-4-methylanilinium hexafluoroantimonate (CMH) curing agent as a thermal latent initiator on thermal behaviors, rheological properties, and thermal stability of diglycidylether of bisphenol A (DGEBA) epoxy cationic system was investigated. From DSC measurements of DGEBA/CMH system, it was shown that this system exhibits an excellent thermal latent characteristic at a given temperature. The conversion and conversion rate of DGEBA/CMH system increased with increasing the concentration of initiator, due to high activity of CMH. Rheological properties of the system were investigated under isothermal condition using a rheometer The gelation time was obtained from the analysis of storage modulus (G'), loss modulus (G"), and damping factor (tan $\delta$). As a result, the reduction of gelation time was affected by high curing temperature and concentration of CMH, resulting in high degree of network formation in cationic polymerization, due to difference of activity. The thermal stability of the cured epoxy resin was discussed in terms of the activation energy for decomposition and thermal factors determined from TGA measurements.ents.

• Applied Chemistry for Engineering
• /
• v.10 no.7
• /
• pp.1046-1051
• /
• 1999

Cure behavior and thermal stability of the different ratio of diglycidylether of bisphenol A(DGEBA)/trimethylolpropane triglycidylether(TMP) epoxy blends initiated by 1 wt % N-benzylpyrazinium hexafluoroantimonate (BPH) as a cationic latent catalyst were studied using DSC and TGA, respectively. Latent properties were performed by measurement of the conversion as a function of temperature using dynamic DSC. Dynamic DSC thermograms of DGEBA/TMP blends revealed that the weak peak was formed by complex formation between the hydroxyl groups in DGEBA and BPH, and between epoxides and BPH in low temperature ranges. The strong peak was considered as an exothermic reaction by the formation of three-dimensional network in high temperature ranges. Isothermal DSC revealed that the reaction rate of the blends was found to be higher than that of the neat TMP. The thermal stabilities in the cured resins were increased with increasing the DGEBA content. These results could be interpreted in terms of the stable aromatic structure, existence of hydroxyl group and high molecular weight of DGEBA.

• Proceedings of the Korean Fiber Society Conference
• /
• 2000.04a
• /
• pp.113-116
• /
• 2000

• Clean Technology
• /
• v.21 no.1
• /
• pp.76-82
• /
• 2015

Volatile organic compounds (VOC) free adhesives have been interested by many scientists and engineers due to environmental regulations and the safety of industrial workers. In this work, a series of composites composed with bisphenol A epoxy resin used as solvent, dicyandiamide, and promoter were prepared to investigate the most appropriate molar ratio for steel-steel adhesion. The cured test specimen of each composite were measured with universal testing machine (UTM) to figure out mechanical properties such as tensile strength, Young’s modulus, and elongation. Furthermore, the lap shear strength of the specimen was tested with UTM while impact resistance was measured with Izod impact tester. The composite whose molar ratio of epoxy resin to curing agent is 1 : 0.9 (sample 3), showed better tensile strength, coefficient of elastic modulus, elongation, and impact strength than other composites did. The highest tanδ from dynamic mechanical analysis (DMA) was observed from sample 2 (epoxy resin: dicy = 1 : 0.7) while sample 3 showed slightly lower tanδ than that of 2. The morphology of the fracture surface of the cured composites from SEM showed that the number of subtle lines on the surface caused by impact increase as the contents of amine curing agent accrete. Furthermore, the viscosity change of sample 5 (epoxy resin: dicy = 1 : 1.3) was observed to confirm its storage stability.

• The Korean Journal of Rheology
• /
• v.10 no.2
• /
• pp.92-97
• /
• 1998

열잠재성 경화제인 N-benzylpyrazinium hexafluoroantimonate (BPH)를 이용하여 함 량에 따른 DGEBA계 에폭시 수지의 경화반응에서의 유변학적 특서 및 반응속도를 연구하 였다. 경화시의 활성화 에너지를 Barrett 방법을 이용한 동적 DSC 측정방법으로 조사 하였 다. DSC 실험 결과 BPH의 함량이 증가할수록 활성화 에너지는 감소함을 알수 있었다. Rheomter를 이용하여 DGEBA/BPH 계의 유변학적 특성을 등온경화와 tdmdhsrud화 조건하 에서 살펴보았다. BPH의 함량이 증가함에 따라 겔화점 도달시간 빠르게 나타나는데 이는 낮아진 활성화 에너지에 기인한 것으로 사료된다. 두 번째 damping 피크를 이용하여 유리 화점을 측정하여 Time-Temperature-Transformation (T-T-T) cure diagram을 작성한 결 과 열잠재성 경화제의 특성인 일정온도 이상에서 활성이 나타남을 확인할수있었다.

• The Korean Journal of Rheology
• /
• v.11 no.2
• /
• pp.135-142
• /
• 1999

The effects of 1 wt.% N-benzylpyrazinium hexafluoroantimonate (BPH) as a thermal latent initiator and blend compositions composed of 0, 5, 10, 20 and 40 wt.% of phenol-novolac resin to epoxy resin were investigated in terms of cure kinetics, thermal stabilities and rheological properties. Thermal latent properties of BPH were measured from the conversion as a function of reaction temperature on a dynamic DSC. This cationic BPH system turned out to be an effective thermal latent initiator in the epoxy-phenol curing system. And the increase of phenol-novolac resin concentration led to the decrease in the latent temperature and to the increase of cure activation energy ($E_a$) of the blend system. The thermal stability and activation energy ($E_t$) for decomposition, gel-time and activation energy ($E_c$) for cross-linking from rheometer increased within the composition range of 20~40 wt.% of phenol-novolac resin. This implies that the three-dimensional cross-linking may take place among hydroxyl group within phenol resin, epoxide ring within epoxy resin and BPH.

• Polymer(Korea)
• /
• v.34 no.3
• /
• pp.191-197
• /
• 2010

To improve the curing method of anisotropic conductive film (ACF) at low temperature, it was studied to replace the thermal latent curing agent of imidazole compounds by the curing agent of cationically initiating type. Thermo-mechanical properties such as glass transition temperature, storage modulus, and coefficient of thermal expansion were investigated for the analysis of curing behavior. The reliability of ACF were observed in thermal cycle and high temperature-high humidity test. ACF using cationic initiator showed faster curing, lower CTE, and higher $T_g$ than the case of using imidazole curing agent, which is important for the high temperature stability. Furthermore, ACF using cationic initiator maintained a stable contact resistance in reliability test, although it was cured at low temperature and fast rate. With these results, it was confirmed that the curing method of epoxy had great effect on thermo-mechanical properties and reliability of ACF.