• Journal of the Microelectronics and Packaging Society
• /
• v.27 no.3
• /
• pp.49-54
• /
• 2020

To attach a stretchable/flexible electrode to something or something to on electrode, conductive adhesives must be stretchable/flexible to suit the properties of the electrode. In particular, conductive adhesive require durability and heat resistance, and unlike conventional adhesives, they should also have conductivity. To this end, Epoxy, which has good strength and adhesion, was selected as an adhesive, and a plasticizer and a reinforcement were mixed instead of a two-liquid material consisting of a conventional theme and a hardener, and a four-liquid material was used to give stretchability/flexibility to high molecules. The conductive filler was selected as silver, a material with low resistance, and for high conductivity, three shapes of Ag particles were used to increase packing density. Conductivity was compared with these developed conductive adhesives and two epoxy-based conductive adhesives being sold in practice, and about 10 times better conductivity results were obtained than products being actually sold. In addition, conductivity, mechanical properties, adhesion and strength were evaluated according to the presence of plasticizers and reinforcement agent. There was also no problem with 60% tensile after 5 minutes of curing at 120℃, and pencil hardness was excellently measured at 6H. As a result of checking the adhesion of electrodes through 3M tape test, all of them showed excellent results regardless of the mixing ratio of binders. After attaching the Cu sheet on top of the electrode through conductive adhesive, the contact resistance was checked and showed excellent performance with 0.3 Ω.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.3 no.3
• /
• pp.212-219
• /
• 2015

This study focuses evaluating the efficiency and performance evaluation of composite type sheet-membrane waterproofing method that utilizes a separation behavior inducement system designed to resolve the chronic problems of disintegration and damage of overlap areas of waterproofing layers. As the result of the test, the tensile strength value was at 13.8N/mm and elongation rate at 587% for the separation behavior inducement type specimen, and the compared specimens had 14.2N/mm for tensile strength and 335% for elongation rate. For the separation behavior adhesion method specimen, when tensile stress or displacement occurred, the Zero-Span tension occurrence did not follow, which resulted in that the bottom sheet layer and the top membrane layer did not simultaneously becoming damaged. When undergoing the top and bottom layers were separated through separation behavior due to lack of flexibility, the bottom layer began to damage at the primary stage, and with the allowed boundary the upper membrane layer began to display flexibility and showed continuous displaced resulting in secondary phase damaging.

• Journal of Surface Science and Engineering
• /
• v.36 no.3
• /
• pp.251-255
• /
• 2003

With increasing environmental demands in surface treatment of steel sheets, the passivation layers containing hexavalent chromium $(Cr^{+6})$ are being replaced by non-chromium or trivalent chromium compounds. After review on the various types of inorganic compounds, the zirconates was chosen as the candidate for alternative to sodium dichromate in the aspect of its barrier properties with excellent adhesion to organics. The ammonium zirconium carbonate (AZC) and sodium hexafluorozirconate (SFZ) could be reach $70-80\%$ level of CDC (cathodic dichromate) treatment by their single applications. But high porosity in the AZC layer and poor electrical conductivity of SFZ solution limit the single application of zirconate. Mixed composition of zirconates to compensate their inferiorities or incorporation of organic compounds to seal the porosity seems to be inevitable to match up the target level of Cr-free passivation of tinplate.

• Journal of the Korean Ceramic Society
• /
• v.31 no.4
• /
• pp.427-435
• /
• 1994

Cu-metallized low firing temperature substrates were synthesized by cofiring green sheet of cordierite-based glass with Cu. By Sol-Gel method, Cu powder was coated with borosilicate gel which should act as a glass frit in Cu paste during cofiring. Theoretical weight ratios of Glass/Cu were controlled to be 2.5, 5, 10 and 15% by varying alkoxide concentrations. Average particle size of coated Cu was 0.629~0.674 ${\mu}{\textrm}{m}$ in comparison to that of as-received Cu(0.596 ${\mu}{\textrm}{m}$), which increased with alkoxide concentration but did not increase above certain concentration. The weight ratios of coated layer were 2.11~5.37%. The properties of Cu-metallized low firing temperature substrate, cofired at 90$0^{\circ}C$ for 1h under H2/N2 atmosphere, were as follows; sheet resistance was 13~43 m{{{{ OMEGA }}/$\square$, adhesion strength was 1.0~2.1 kgf/$\textrm{mm}^2$. From the observations of SEM photographs, the gel coated on Cu performed excellently as a glass frit.

• Transactions of Materials Processing
• /
• v.31 no.4
• /
• pp.186-193
• /
• 2022

The application of UHSS sheet is being expanded up to 50% to reduce the weight of automobiles and improve safety. However, due to the high strength and low elongation of the ultra-high tensile strength steel sheet, product defects such as spring back and mold defects such as cracks and chippings also occur. In this study, Pin/Ring on Disc and Spiral wear tests were conducted to evaluate the durability of Ti/Cr-coated molds for forming 1.2GPa grade UHSS sheets. Component analysis and thickness were measured for each coating layer, and hardness and adhesion were investigated to determine mechanical properties. Combining the results of various wear tests, it was found that the TiAlN coating had the best wear and sticking resistance.

• Journal of Adhesion and Interface
• /
• v.21 no.3
• /
• pp.101-106
• /
• 2020

In this study, epoxy-modified acrylate was synthesized. The synthesized acrylate was added to the composition for sheet molding compound (SMC) in the range of 5 phr to 15 phr. The prepared SMC prepreg was molded at high temperature and pressure to produce a glass fiber reinforced composite. Physical properties such as tensile and impact strength of the composite were measured, respectively. Experimental data show that the composite with 5 phr of synthesized acrylate has 20% improved tensile strength and 12% improved impact strength than that of the reference sample.

• Journal of Adhesion and Interface
• /
• v.22 no.2
• /
• pp.63-68
• /
• 2021

Unsaturated Polyester Resin (UPR) is in general used as a resin to prepare for composite materials with reinforcing materials such as glass fibers. UPR, a thermosetting resin, is used in industry to prepare for sheet molding compound (SMC) molding prepreg that has excellent productivity and is advantageous for mass production among various molding methods of composite materials. The fiber-reinforced composite material using UPR as a matrix material is light and has the advantage of excellent physical properties, but it is weak against impact and is fragile. Four types of polyurethane were synthesized and added to UPR resin to overcome the shortcomings.

• Journal of the Korean Society of Safety
• /
• v.30 no.1
• /
• pp.21-27
• /
• 2015

In this study, interfacial characteristics between SOFC and Ag paste as current collector was estimated in the high temperature environment. The Ag paste was used to connect the unit cell of SOFC strongly with interconnector and provide the electrical conductivity between them. To confirm electrical conductivity, Ag paste was treated in the furnace at $800^{\circ}C$ for 48 hours. The sheet resistance of Ag paste was measured to compare the resistance values before and after the heat treatment. Also, the four-point bending test was performed to measure the interfacial adhesion. The unit cell of SOFC and $SiO_2$ wafer were diced and then attached by Ag paste. The $SiO_2$ wafer had the center notch to initiate a crack from the tip of the notch. The modified stereomicroscope combined with the CCD camera and system for measuring the length was used to observe the fracture behavior. To compare the characteristics before heat treatment and after heat treatment, the specimen was exposed in the furnace at $800^{\circ}C$ for 48 hours and then the interfacial adhesion was evaluated. Finally, the interfacial adhesion energy quantitatively increases $1.78{\pm}0.07J/m^2$ to $4.9{\pm}0.87J/m^2$ between the cathode and Ag paste and also increase $2.9{\pm}0.47J/m^2$ to $5.12{\pm}1.01J/m^2$ between the anode and Ag paste through the high temperature. Therefore, it is expected that Ag paste as current collector was appropriate for improving the structural stability in the stacked SOFC system if the electrical conductivity was more increased.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2005.11a
• /
• pp.183-186
• /
• 2005

This study investigates material properties of epoxy resins and reinforced materials for adhesion repairing-reinforced of RC construction. According to the test. elasticity modulus of mortar indicated 16-26(GPa) and that of concrete was 18-27(GPa). It became decreased as mixture proportion, W/C and fluidity of both mortar and concrete increased In addition the elasticity modulus of epoxy resins exhibited around 45.3-220(GPa), while that of steel plate and Carbon Bar indicated 338(GPa) and 34.1 (GPa), respectively. It is obvious that individual materials had big different value of elasticity modulus. Meanwhile, thermal expansion coefficients of mortar was 10-13 ${\mu}\varepsilon$ /$^{\circ}C$ and that of concrete was 9-11 $\mu \varepsilon$ /$^{\circ}C$ The increase of mixture Voportion and W/C resulted in lower value of thermal expansion coefficients and the increase of flow and slump exhibited slightly higher value. The epoxy resin indicated 41-54 ${\mu}\varepsilon$ /$^{\circ}C$ which is 4-5 times larger value than concrete and steel plate and Carbon Bar was 11.93 ${\mu}\varepsilon$ /$^{\circ}C$ and -1.68 ${\mu}\varepsilon$ /$^{\circ}C$ respectively. Hence, the adhesion strength of the epoxy resins should be considered before it is used in field condition, due to different thermal expansion coefficient of each material.

• YAKHAK HOEJI
• /
• v.42 no.2
• /
• pp.187-195
• /
• 1998

In order to ameliorate disadvantages of buccal ointments and mucoadhesive tablets used for the treatment of aphthosis, a thin mucoadhesive patch containing triamcinolone acetoni de was designed and evaluated for the pharmaceutical properties. The adhesive gel layer consisting of Noveon AA-1, hydroxypropylcellulose-M and ethylcellulose N 100, and the protective gel layer of ethylcellulose N 100, Eudragit RSPO and castor oil have been formulated and various properties such as viscosity of drug gel layer, thickness, in vitro adhesion time, adhesive strength, surface pH, content uniformity and drug release are tested. The mean viscosity of drug-containing gel layer was found to increase with increasing amount of Noveon OAA-1 or hydroxypropylcellulose-M. The optimum formulation showed the thickness of 171 ${\mu}$m, surface pH of 4.6, in vitro adhesion time of 8 hours and adhesive strength of 272.7g/sheet. The drug content of each patch was relatively homogeneous with the value of 273${\pm}$6.77g. Drug release study showed that compared to mucoadhesive tablet, the patch showed a faster drug release. Drug release was delayed by hydroxypropylcellulose-M, but not by ethylcellulose N 100. The patches prepared were nonirritant and the muco adhesion was better than the commercial product (AftachR) on the market. Based on these results, this mucoadhesive patch is expected to be an effective dosage form for the treatment of aphthosis.