• 한국분말재료학회지
• /
• 제15권2호
• /
• pp.119-124
• /
• 2008

To increase pot life in the formulation mixed with bisphenol F epoxy resin, anhydride-based curing agent, and imidazole-based curing accelerator powders as a paste material for high-speed RFID chip bonding, size variation of the imidazole-based powders and a coating method of the powders were adopted in this study. In experiment with regard to the size variation, the pot life was not outstandingly increased. Through the idea using the coating method, however, the pot life was increased up to 4.25 times in comparison with the addition of initial imidazole-based powders. Consequently, successive bonding of RFID chip could be performed with very short time of 5sec using the suggested formulation having improved pot life.

• 대한기계학회논문집A
• /
• 제26권11호
• /
• pp.2374-2382
• /
• 2002

Aluminum alloy/aramid fiber reinforced plastic(Al/AFRP) laminates consists of high strength metal(A15052) and laminated aramid fiber with structural adhesive bond. The mixture ratio effect of epoxy resin curing agent accelerator on the tensile strength and T-peel strength characteristic in Al AFRP laminates were investigated in this study. The epoxy. diglycidylether of bisphenol A(DCEBA), It'as cured by methylene dianiline(MDA) with or without an accelerator(K-54). Eight different kinds of resin mixture ratios were selected for the test , five kinds of Al/AFRP laminates were named as Al/AFRP(1) and three others of Al/AFRP laminates were named as Al/AFRP(2). The comparison of tensile strength and T-peel strength with variation of resin mixture ratio were studied. Respectively. Al/AFRP(1) and Al/AFRP(2) indicated approximately 6.0 times and 7.0 times more improved maximum tensile strength in comparison with those of monolithic A15052. Al/AFRP(2) indicated approximately 1.5 times more impoved maximum T-peel strengths in comparison with those of Al/AFRP(1). As results. Al/AFRP(2) turned out to have more effective characteristics on the tensile strength and T-peel strength than those of Al/AFRP(1).

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
• /
• pp.266-267
• /
• 2014

In order to develop concrete generating compressive strength of 10MPa~15MPa aging for 6hours in the room temperature curing, Hardening accelerator containing Ca²⁺ mixed with rapid hardening portland cement containing C₃S in quantity. The result was that the more addictive contents of Hardening accelerator is, the more greatly early compressive strength was improved. That's because the composition of Ca(OH)₂ was mass-produced at early-ages.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2014년도 추계 학술논문 발표대회
• /
• pp.135-136
• /
• 2014

In this study, the experimental study on the early age compressive strength of cement mortar using anti freezer and hardening accelerator at low temperature was conducted. For this study, all of materials for experiment were kept in a low temperature for 24 hours before mortar mixing. After mortar curing at low temperature, compressive strength was measured at the early ages. Furthermore, properties of hardened cement material was analysed using TG-DTA and MIP.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
• /
• pp.56-58
• /
• 2013

In order to develop concrete generating compressive strength of 15MPa~30MPa aging for 6~12 hours in the room temperature curing, Hardening accelerator containing Ca²⁺ mixed with rapid hardening portland cement containing C₃S in quantity. The result was that the more addictive contents of Hardening accelerator is, the more greatly early compressive strength was improved. That s because the composition of Ca(OH)₂ was mass-produced at early-ages.

• 콘크리트학회논문집
• /
• 제14권6호
• /
• pp.942-948
• /
• 2002

콘크리트의 초기동해는 응결과정이거나 종결 후에도 충분한 강도발현이 되지 않은 단계에서 콘크리트중의 수분이 동결함에 따라 발생하는데, 초기동해를 방지하기 위해서는 콘크리트가 동결하기 이전에 일정강도를 조기에 발휘하는 것이 필요하다. 따라서, 이에 대한 많은 대처방안이 제시되고 있는데, 최근에는 내한촉진제를 사용하는 방법이 검토되고 있다. 따라서, 본 연구에서는 내한촉진제를 혼합한 콘크리트의 실무 활용 가능성을 검토할 목적으로 콘크리트 단계에 앞서 모르터 단계에서 내한촉진제의 동결온도, 응결시간 및 염화물량 등을 측정하고, 아울러 정온 및 변온조건에서 양생한 모르터의 강도특성도 검토함으로서 내한 촉진제를 사용한 한중콘크리트의 개발에 기초자료를 제시하고자 하였다. 연구결과, 내한촉진제를 혼합한 모르터의 동결온도는 내한촉진제의 사용량이 증가할수록 낮아지는 반면, 촉진형 감수제의 경우는 동결온도 저하에 거의 영향이 없는 것으로 나타났으며, 응결특성은 양생온도가 낮을수록, 내한촉진제의 응결촉진 효과가 우수한 것으로 평가되었다. 염화물량은 공히 KS F 4009의 관리규준을 만족하고 있었다. 강도증진성상은 내한촉진제를 혼합한 경우, 로지스틱 곡선식을 이용한 강도증진해석 결과와 거의 유사한 것으로 나타난 반면, 정온조건으로 영하5$^{\circ}C$이고, plain과 촉진형 감수제를 사용한 경우는 강도증진해석 결과의 표준오차가 상대적으로 매우 크게 나타나, 강도증진해석을 목적으로 사용되는 로지스틱 곡선이나 적산온도와 압축강도의 관계에서 적용성이 매우 적은 것으로 평가되었다. 한편 내한촉진제를 혼합한 모르터의 압축강도가 5.0 N/$\textrm{mm}^2$을 발휘하게 되는 적산온도는 각각 20~30$^{\circ}$CD(K), 30~40$^{\circ}$CD(B), 40$^{\circ}$CD(S)이후인 것과 같이 내한촉진제의 종류에 따라 크게 상이한 것으로 나타났다. 정온 및 변온양생조건에 따른 한중콘크리트의 압축강도는 동일 적산온도라 할지라도 정온조건보다는 변온조건이 더 유리한 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
• /
• pp.24-30
• /
• 1996

Nowadays, Government is modifying envioronment regulatons, but PC factories, having been constructed in 1990, are running out heavy cost in disposal of waste concrete, and hardly studying how accelerator curing method affects in compressive strength. In this study, possibility that waste concrete, produced in PC factory, can be used in PC products, is reviewed, and them captures strength characteristics by curing method. The results can be summed as follows. In order to recycle concrete the mix ratio of recycled aggregate to 50 percent of less than must decrease also in summer of four seasons strength gap by curing method is very small.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2012년도 추계 학술논문 발표대회
• /
• pp.221-222
• /
• 2012

This study is to high early concrete development which reveals 14 MPa within 12 hours in order to reduce the mold time of dismantlement and not do the steam curing of the precast concrete product. About (40~50) min could shorten the final setting time if the coagulation test result cement amount 100 kg/m3 was increased. In the case of the compressive strength, it was exposed to be satisfied the target value with the cement amount 500 kg/m3 combination according to the hardening accelerator addition.

• 방사선산업학회지
• /
• 제4권1호
• /
• pp.19-23
• /
• 2010

Vinyl ester (VE) resins, introduced in the late 1960s, have made large strides in reinforced plastics applications as adhesive and matrix materials on their appropriate mechanical performance characteristics in the glassy state. Generally, VE resins are a group of dimethacrylate resins based on bisphenol A type epoxy resin. They exhibit easy handling properties as well as good resistance to most chemical agents due to their mechanical and thermal properties. In this study, the effects of curing methods of vinyl ester resins on gel contents, flexural strength and dynamic mechanical properties were investigated. Thermal curing (room temperature, $80^{\circ}C$) and electron beam curing were used to crosslink a VE resin/styrene complex (65/35 wt%) with methyl ethyl ketone peroxide (MEKPO) as a catalyst and an 8 wt% cobalt naphthenate in styrene solution as a accelerator. For the samples, gel contents as well as flexural strength and dynamic mechanical properties were characterized and compared by soxhlet apparatus, universal testing machine (UTM) and dynamic mechanical analysis (DMA). As a result, the electron-cured VE resin was confirmed as a better condition than those for gel contents, flexural strength and dynamic mechanical properties, respectively.

• Elastomers and Composites
• /
• 제16권1호
• /
• pp.3-13
• /
• 1981

The purpose of this dissertation is to study the physical properties of cellular rubber products for industrial use. Vulcanization characteristics were investigated by usingcure curve that had obtained by means of Rheometer. The results of physical properties, vulcanization characteristics and foaming states are as follows. 1. The test results for vulcanization characteristics of NR compounds indicated that in the recipe R-1. When accelerator D is used, the optimum conditions of vulcanizate are obtained, while formula R-2 and R-3 have shown higher torgue at curing time, $1{\sim}2$ minutes. Cellular rubber product test in terms of compression set and compression deflection has also met the requirements of SAE. 2. For SBR compounds, S-1 formula was the best in terns of vulcanization characteristics, and for the blowing structure of cellular rubber products, formula S-3 in which accelerator M is added was fair. All other test results, such as compression set and compression deflection properties met SAE requirements. 3. NBR compound (N-1) including accelerator TT was the best in terms of vulcanization characteristic and also blowing structure. All other properties listed above met requirements, particulary for oil resistance test. 4. In the test of EPDM compounds, when mixed accelerator, M and TT, is used(formula E-1) the best results were obtained. Since EPDM is hydrocarbon elastomer, oil resistance test failed. All other properties met the requirement specified in SAE.