• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.58-58
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• 2011

CNT 나노기술을 응용한 IT산업용 적층간지용 ESD(정전방전, Electrostatic Dissipation)PU 발포필름의 제조 가공기술 및 상품화 개발은 전자제품 패키지에 요구되는 쿠션성과 정전방전 기능을 갖는 폴리우레탄 발포 필름의 제조기술을 확립함으로써 가능 할 수 있다. 특히 IT산업용 필름제품이 개발되면 ESD 성능을 발휘하게 됨으로서 정전기 쇼크에 의한 각종 전자제품의 오작동이나 파손 방지가 가능하게 되어 포장재, 자동차, 전자제품의 하우징 등으로 사용될 수 있게 된다. 현재까지 ESD 기능을 부여하기 위해서 사용되는 충전재로는 금속섬유, 금속플레이크, 탄소섬유, 카본블랙 등이 있으며, 최근 탄소나노튜브를 응용한 연구가 많이 진행되고 있는데 탄소나노튜브는 직경이 수십nm, 종횡비 1000이상의 나노섬유형태로 서 전기전도성이 구리수준으로 알려져 있고 소량을 충전할 시 기계적 특성도 오히려 증대하는 장점을 가지고 있으며 전기적 특성으로는 상대적으로 낮은 나노튜브 함량에서는 ESD를 들 수 있고 높은 함량에서는 전자파 차폐성까지 기대되고 있다. 본 연구에서는 우수한 인장강도, 기계적 강도, 열적 안정성, 내약품성을 가지면서 습식 또는 용융공정을 통해 용이하게 시트, 필름, 코팅제를 제조할 수 있는 방수, 투습방수성을 가지는 유연재료인 폴리우레탄(PU) 1액형 PU에 MWNT 함량이 3wt%인 IPA/MWNT 분산용액을 PU 함량 대비 20, 30, 40파트로 함유시켜 $120^{\circ}C$에서 2분 건조시켜 제조한 그라운드 필름에 2액형 PU와 IPA/MWNT 분산용액에 발포제를 첨가하여 발포온도 140, 150, $160^{\circ}C$에서 5분간 건조시켜 시료 필름을 제조하였다. 제조된 필름의 전기전도성 측정은 부피저항과, 표면저항을 각각 측정하여 확인하였으며, 필름의 마찰 대전압은 E.S.T-7 마찰 대전압 시험기를 이용하여 표면 마찰 대전압과 반감기를 측정하여 확인하고, 필름의 물리적 특성은 인장시험기를 이용하여 breaking stress, breaking strain을 구하였다. 필름의 표면 특성은 영상 현미경 시스템을 사용하여 ${\times}1000$ 배율로 측정하여 분산특성과의 연관성을 확인하였다.

• Journal of the Korean Society of Safety
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• v.25 no.4
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• pp.13-18
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• 2010

To investigate electrostatic ignition hazards of commercial gasoline used in the gas station, experiments were conducted dealing with the minimum ignition energy(MIE) of several kinds of gasoline under the various temperature. The conductivity of gasoline that was required for an accurate risk assessment as well as the MIE were also examined. The solvent ignitability apparatus which can heat up the inside of the vessels up to $210^{\circ}C$ was used in this study. Four kinds of premium gasoline and four kinds of regular gasoline, differing with respect to the companies, were used as test specimens. The following results were obtained: (1) all gasoline specimens were so sensitive that even an electrostatic discharge with a very low energy, such as about 0.5mJ, could ignite them. The ignitability of premium gasoline was constant irrespective of the companies. On the other hand, the ignitability of regular gasoline was variable depending on the company. (2) The MIE of all specimens depended markedly on the temperature; in other words, an increase in temperature decreases the ignition energy value. (3) The conductivity values of all specimens were low. Those must be taken into consideration in electrostatic risk assessment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.529-534
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• 2002

It was recommended for all ship engaged in international voyages to carry the dedicated Digital Selective Calling receiver, DSC equipment, VHF transceiver, etc according to Global Maritime Distress & Safety System. Also International Maritime Organization recommended for navigation and communication equipments to applicate the EMC regulations, therefore most of electronic equipments using in the vessel to be faced with problems to cope with new regulations. This study has applied and analyzed the EMC for an equipment integrated with Ch.70 dedicated DSC receiver, DSC equipment, VHF transceiver and groped for solutions to cope with. The test has applied the electromagnetic interference such as the measurement for unwanted emissions from conductive & radio emission and the electromagnetic susceptibility such as the immunity from voltage, frequency variation and electro static discharge, hence comes to be understand the problems related with the power and the earth.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.3
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• pp.109-113
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• 2005

It has been reported that the failure phenomenon and variation of electrical characteristic due to the effect of electrostatic discharge(ESD) in silicon devices. But we had fess reports about the phenomenon due to the ESD in the compound semiconductors. So there are a lot of difficulty to the phenomenon analysis and to select the protection method of main circuits or the devices. It has not been reported that the relation between the ESD stress and GaN devices, which is remarkable to apply the operation in high temperature and high voltage due to the superior material characteristic. We studied that the characteristic variation of the AlGaN/GaN HEMT current, the leakage current, the transconductance(gm) and the failure phenomenon of device due to the ESD stress. We have applied the ESD stress by transmission line pulse(TLP) method, which is widely used in ESD stress experiments, and observed the variation of the electrical characteristic before and after applying the ESD stress. The on-current trended to increase after applying the ESD stress. The leakage current and transconductance were changed slightly. The failure point of device was mainly located in middle and edge sides of the gate, was considered the increase of temperature due to a leakage current. The GaN devices have poor thermal characteristic due to usage of the sapphire substrate, so it have been shown to easily fail at low voltage compared to the conventional GaAs devices.

• Journal of the Korean Society of Safety
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• v.26 no.3
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• pp.15-22
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• 2011

Explosion and fire cause about 30 reported industrial major accidents a year by ignition source which discharge of electrostatic generated to flammable gas, vapor, dust and mixtures. It brings economically and humanly very large loss that accident was caused by fire and explosion from electrostatic discharge. Thus, it is very important that electrostatic discharge energy is to be control below not to be igniting flammable mixtures. There are two kinds of analysis model for electrostatic discharge, human body model and machine model. Human body model is available the parameter of human's electrical equivalent that capacitance is 100 pF, resistance is $1.5k{\Omega}$. To simulate and visualize the electrostatic discharge from human body need a very expensive and high voltage simulator. In this paper, we measured the value of capacitance and resistance concerned with test materials and sizing of specimen and the value of charged voltage concerned with test specimen and distance to develop an electrostatic charge/discharge simulating tool for teaching with which concerned industrial employee and students. The result of experiments, we conformed that the minimum ignition energy of methane-oxygen mixtures meets well the equation $W=1/2CV^2$, and found out that the insulating material and sizing of equivalent value having human body mode are the poly ethylene of 200 mm and 300 mm of diameter. Developed electrostatic charge/discharge simulating tool has many merits; simple mechanism, low cost, no need of electric power and so on.

• Journal of the Korean Society of Safety
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• v.39 no.2
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• pp.1-8
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• 2024

Unwanted effects of electrostatic phenomena occur in various industries. Electrostatic problems originating from the human body in flammable atmospheres in the industry are especially concerning. A substantial volume of experimental data on the electrostatic charging voltages created on the human body owing to the rubbing of apparel were generated and reviewed during this study. The data were reviewed to determine whether the resultant charging levels of the human body are hazardous in flammable atmospheres. This study was conducted under several conditions, such as different fiber types used in apparel, shoe types, and relative humidities (RHs). The following conclusions were drawn in this study. ① The electrostatic charging levels of the human body owing to the rubbing of apparel increase with the increase in the surface resistances of apparel; however, the electrostatic charging levels may be different depending on the condition of the cloth surface. ② The discharging energy of 1.98-18.5 [mJ] from the human body exceeds the minimum ignition energy of most flammable materials, when removing an overcoat made of polyester, cotton and wool under severe conditions such as wearing height-raising shoes for men. ③ When removing antistatic apparel, the maximum discharging energy of 0.128 mJ from the human body is dangerous if the minimum ignition energy of the flammable material is between 10^-5-10^-4 [J] Grade; however, a minimum ignition energy of 10^-3 J Grade of the flammable material is considered safe. ④ While wearing antistatic shoes, the electrostatic charging voltage generated in the human body when removing an overcoat is 30 V; therefore, wearing such shoes is a suitable countermeasure when handling flammable materials. However, the antistatic abilities of shoes reduce when thick socks are worn. ⑤ As RH increases, the electrostatic charging levels of the human body decrease. ⑥ The electrostatic charging levels of the human body from removing a cotton overcoat can ignite the majority of flammable materials when RH is less than 30% under severe conditions such as wearing height-raising shoes for men.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.63-63
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• 2012

전자제품 패키지에 요구되는 쿠션성과 정전방전 기능을 갖는 폴리우레탄 발포 필름의 제조기술을 확립하게 되면 IT산업용에 적용 가능한 필름제품이 개발되어 ESD(정전방전, Electrostatic Dissipation) 성능을 발휘하게 됨으로서 정전기 쇼크에 의한 각종 전자제품의 오작동이나 파손 방지가 가능하게 되어 포장재, 자동차 전자제품의 하우징 등으로 사용될 수 있게 된다. 전도성 고분자인 Polyaniline (PANI)은 다른 여러 고분자와 비교하여 볼 때 다른 유형의 전도성 고분자보다 합성하기가 쉽고 높은 전기전도도를 보임은 물론 열적 및 대기 안정성이 우수하며 가격이 저렴한 장점을 가지고 있다. 본연구는 CNT 나노기술을 응용한 IT산업용 적층간지용 ESD PU발포필름의 제조 가공기술 및 상품화 개발을 수행하고자 방수, 투습방수성을 가지는 유연재료인 폴리우레탄(PU)의 1액형 PU와 DMF에 PANI의 함량을 5, 10, 15, 20, 25, 30wt%로 변화시켜 제조한 PANI/DMF 분산용액과 IPA/MWNT 3wt% 분산용액의 혼용비에 변화를 주어 $120^{\circ}C$에서 2분 건조시켜 그라운드 필름을 제조하였다. 그리고 2액형 PU와 IPA/MWNT 3wt% 분산용액과 발포제를 사용하여 발포온도 $150^{\circ}C$에서 5분간 건조시켜 발포필름을 제조하였으며 이들의 전기적 특성과 역학적 특성을 조사하였다. 제조된 필름의 전기전도성은 전기저항측정기 KEITHLEY 8009를 사용하여 부피저항과, 표면저항을 각각 측정하여 확인하였으며, 필름의 마찰 대전압은 E.S.T-7 마찰 대전압 시험기를 이용하여 표면 마찰 대전압을 측정하여 확인하고, 필름의 물리적 특성은 인장시험기를 이용하여 breaking stress, breaking strain을 측정하였다. 필름단면의 CNT 발포특성은 주사전자현미경(SEM)을 사용하여 측정하여 발포특성과 물성과의 연관성을 확인하였다. 그 결과 필름의 전기적 특성은 PANI가 30% 함량일 때 전반적으로 낮은 저항값이 측정되었으며, 마찰대전압을 측정한 결과 대부분의 시료가 0에 가까운 낮은 값을 가졌다. 필름의 물리적 인장특성은 PANI가 10wt%의 함량일 때 가장 높은 절단강도를 가졌으며 분산용액의 혼용비에 따른 경향성은 나타나지 않았다. 필름의 단면형상을 확인하여 발포특성을 분석한 결과 PANI의 함량에 따라 발포 cell의 크기는 뚜렷한 경향성을 보이지 않았으나 30wt%의 PANI/DMF 분산용액 20part(gr)와 3wt% IPA/MWNT 분산용액 40part(gr)로 제조한 시료의 cell이 가장 균일하고 고르게 발포되었으며, 3.90E+06ohm으로 가장 낮은 표면저항 값으로 측정되어 가장 좋은 전기전도성을 가짐을 확인하였다.