Noh S.M.,PPG Industries |
Noh S.M.,Korea University |
Lee J.W.,PPG Industries |
Nam J.H.,PPG Industries |
And 3 more authors.
Progress in Organic Coatings
UV-thermal dual-curable, hydroxyl- and methacrylate-functionalized urethane oligomers with different contents of unsaturated double bonds and hydroxyl groups have been synthesized and incorporated into automotive clearcoats to investigate their curing and scratch behaviors. Dynamic mechanical analyses (DMA) and FT-IR analyses were performed to observe the variation of the crosslinking networks that resulted from the chemical reactions by UV and thermal dual-curing operations with varying curing conditions, such as UV dose, thermal curing time, thermal curing temperature, and curing sequence. The scratch behaviors of dual-cured automotive clearcoats were analyzed via nano-scratch tests, accompanied with scratch images simultaneously visualized using scanning electron microscopy (SEM). The mechanical and chemical properties, such as impact resistance, pencil hardness, acid-etch resistance, and stone-chip resistance, of dual-curable clearcoats were also compared with those of UV mono-cure and 1 K thermal-cure clearcoats. The results clearly showed that the dual-curing process induced a considerably higher degree of crosslinking for the cured clearcoats prepared from the dual-curable oligomers, melamine crosslinkers, and photoinitiators. Their mechanical properties including scratch resistance were also noticeably improved via the UV-thermal curing sequence, which led to an increased conversion rate of double bonds compared with clearcoats produced using the thermal-UV curing sequence. The best conditions for high crosslinking density as well as high hardness and modulus were 2400 mJ/cm 2 at 150 °C for 10 min in the UV-thermal curing process. This result was corroborated from the reaction kinetics and surface images of the scratched clearcoats captured by SEM. © 2012 Elsevier B.V. Source
Kim K.-W.,Korea Atomic Energy Research Institute |
Hyun J.-T.,Techwin Co. |
Lee K.-Y.,Korea Atomic Energy Research Institute |
Lee E.-H.,Korea Atomic Energy Research Institute |
And 2 more authors.
Korean Journal of Chemical Engineering
We compared the electrodialysis performance for HNO3 and NaOH recovery from NaNO3 solution by conventional electrodialysis (ED) and electrodialysis with bipolar membranes (EDBM) at constant current and constant voltage. The individual resistances of the components of the electrodialysis systems were also evaluated. The electrodialysis extent for HNO3 and NaOH recovery from NaNO3 solution was almost proportional to the total amount of electricity supplied to the system, regardless of the operation mode and the electrodialysis systems. For the same volume of feed solution, the energy consumption and current efficiency differed depending on the operation mode and the electrodialysis system. In both the ED and EDBM systems, the conductivity of the feed solution strongly affected the overall cell resistance after approximately 50% of the ions in the feed solution had migrated. © 2013 Korean Institute of Chemical Engineers, Seoul, Korea. Source
Techwin Co. | Date: 2014-02-18
The present invention relates to a scrubber system having an automatic generator for an oxidizing-absorbing agent. The scrubber system comprises a scrubber and an oxidizing-absorbing agent generator. The scrubber includes a pollutant gas inlet through which air pollutants are introduced, a treated gas outlet through which the pollutant gas which has been treated is discharged, and a treated water outlet through which wastewater which has been used to treat the pollutant gas is discharged. The oxidizing-absorbing agent generator generates an oxidizing-absorbing agent by electrolyzing saline water or seawater in the scrubber, and supplies the generated oxidizing-absorbing agent into the scrubber to treat the pollutant gas introduced through the pollution gas inlet, thereby removing harmful substances.
Techwin Co. | Date: 1990-09-04
articles of sportswear, exercise wear, leisure and casual wear; namely, tops, shirts, jackets, shorts, pants, trousers, unitards, leotards, bodysuits, head bands, wrist bands, swimwear, lingerie, underwear, nightgowns, corselets, overalls, jerseys, shoes, boots, stockings and pantyhose.
Techwin Co. | Date: 2004-07-20
REACTION VESSELS FOR CHEMICAL AND ENVIRONMENTAL PROCESSING, REACTION VESSELS FOR CHEMICAL AND WATER TREATMENT PROCESSING.