• 한국환경과학회지
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• 제17권8호
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• pp.925-932
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• 2008

Manufactures of automotive repair finishes are tending to reduce more and more the level of volatile organic compounds (VOCs) in their paint processes in order to comply with increasingly strict environmental legislation. The production of high solids paints is a way to solve this problem. However, the application of high-solids paints is limited primarily by the viscosity of resin which is strongly related to painting ability: the higher solid content, the lower desired property. In this study, alkyl copolymer with low viscosity was synthesized by the introduction of the monomers with long-side chains and functional groups which improve flexibility and cross-linking density, respectively. The solid content of the paint prepared with the synthesized resin was 80wt% and its VOCs was reduced by 20%, compared to the commercialized paint. Also, the physical and mechanical properties of coatings on steel sheets were similar to commercialized one.

• 대한환경공학회지
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• 제27권7호
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• pp.677-685
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• 2005

본 연구에서는 국내외에서 법적, 제도적 측면의 외적 정비뿐만 아니라, 학계 및 산업계의 제품별 사례분석 및 적용 측면에서 활발한 연구가 진행되고 있는 LCA와 DfE기법을 제조공정에 적용하였다. 구체적으로, 지게차 제조공정을 대상으로 LCA 기법을 적용하여 환경부하가 가장 큰 제조공정을 규명하고, 그 공정에 DfE 기법을 적용하여 친환경적인 제조공정을 설계하였다. 지게차 제조공정에 대해 LCA를 수행한 결과, 영향범주별로는 생태독성과 인간독성에 대해, 그리고 공정별로는 제관공정과 도장공정에서 환경부하가 크게 나타났다. 제관공정에서 환경부하를 줄이기는 현실적으로 어렵기 때문에, 도장공정에서 발생하는 환경부하를 저감하고자 하였다. 이를 위해 지게차의 도장공정에 기존에 사용하고 있는 용제형 도료의 고형분 함량을 늘려 high solid형 도료를 개발하여 적용한 결과, 환경영향(LCA의 환경영향지수)가 20% 저감되었다. 또한, VOC발생량은 약 32%, 도료 사용량은 약 20%의 저감효과를 얻을 수 있었다.

• 한국응용과학기술학회지
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• 제20권1호
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• pp.8-19
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• 2003

Environmental friendly acrylics/urea high-solid paints (BEHCU) were prepared through the curing reaction of acrylics resin(BEHC) containing 70wt% of solids content and butylated urea curing agent. BEHC was synthesized by addition copolymerization of caprolactone acrylate(CLA), 2-hydroxypropyl methacrylate(2-HPMA), ethyl methacrylate, and n-butyl acrylate. The addition polymerization of these monomers, especially including flexible CLA monomer and 2-HPMA monomer with OH funtional group, under appropriate reaction conditions resulted in polymers with controlled glass transition temperature($T_g$) and crosslinking density. The molecular weight($M_w$) of these polymers(BEHCs) was 2940${\sim}$3240 and polydispersity ($M_w/M_n$) was in the range of 1.61${\sim}$1.72. The viscosity and the molecular weight of these acrylic resins increased with increasing $T_g$. The coated films were prepared using curing reaction between BEHC resin and butylated urea curing agent at 100$^{\circ}C$ for 30 minutes. Our experimental resulted showed that enhancement of the coating properties such as adhesion, flexibility, impact resistance, water resistance, and abrasion resistance could be expected through introducing CLA component in acrylic resin for the high-solid content acrylics/urea coatings.

• 한국응용과학기술학회지
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• 제22권4호
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• pp.371-378
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• 2005

In the previous study, three kinds of monomers and the functional monomer, acetoacetoxyethyl methacrylate (AAEM), which could improve the film property and cross-linkage, were polymerzied into acrylic resin copolymers (HSA-98-20, HSA-98-0, HSA-98+20) containing 80% solid content. In this study, the high-solid coatings(HSA-98-20C, HSA-98-0C, HSA-98+20C) were prepared by the curing reaction between acrylic resins containing 80% solid content and isocyanate at room temperature. Various properties were examined for the film coated with the prepared high-solid coatings. The introduction of AAEM in the coatings enhanced the abrasion resistance and solvent resistance of coatings, which indicated the possible use of high-solid coatings for top-coating materials of automobile. The curing times measured by viscoelastic measurement were 350, 264, and 212 min for HSA-98-20C, HSA-98-0C, and HSA-98+20C, respectively. This shows that the curing times become shorter with increasing $T_g$ values.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.382-387
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• 2005

An electrochemical evaluation on the corrosion resistance for heavy anticorrosive paint was carried out for 5 kinds of heavy anticorrosive paints such as High solid epoxy(HE), Solvent epoxy(SE), Tar epoxy(TE), Phenol epoxy(PE), and Ceramic epoxy(CE) as parameters of DFT(Dry Film Thickness, 25${\mu}m$50${\mu}m$, solution condition(Flow of Nonflow). Corrosion current density of HE(DFT 50${\mu}m$ in case of flow condition was larger than that of nonflow condition. However, their values of the other anticorrosive paints were decreased compared to the nonflow condition. The values of AC impedance were increased with increasing of DFT regardless of kinds of anticorrosive paints. And the polarization resistance of cyclic voltammogram showed a good tendency to correspond with well the values of AC impedance measurement. HE and CE had a relatively good corrosion resistance than other heavy anticorrosive paint.

• 한국응용과학기술학회지
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• 제17권4호
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• pp.233-239
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• 2000

To prepare an environmental friendly high-solid coatings an acrylic resin containing 80% of solid content was synthesized by addition polymerization of caprolactone acrylate, n-butyl acrylate, ethyl methacrylate, and 2-hydroxyethyl methacrylate. The conversion was $78{\sim}93%$ and the prepared resin's physical properties are as follows: viscosity, $212{\sim}3424cps: $M_{n}$ $1740{\sim}2400$. There was a trend that viscosity and molecular weight of the resin increased with Tg, but no direct proportionality was observed.

• 한국응용과학기술학회지
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• 제20권3호
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• pp.237-242
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• 2003

The high-solid coatings were prepared by blending the synthesized acrylic resin in the previous paper and hexamethylene diisocyanate-trimer and curing it at room temperature. The characterization of the films of the prepared coatings was performed. The impact resistance, $60^{\circ}C$ specular gloss, cross-hatch adhension, and heat resistance of the films proved to be good, and the pencil hardness and drying time proved to be slightly poor. Especially, there was a remarkable improvement in the heat resistance. This improvement may stem from the regular arrangement of ethyl groups introduced into the acrylic resin. From a viscoelastic measurement using a rigid-body pendulum, curing was accelerated with the $T_g$ value. With the increase in $T_g$, log damp value was lowered and dynamic viscoelasic $T_g$ of a cured film was increased.

• 한국분무공학회지
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• 제13권1호
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• pp.42-50
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• 2008

In the present work, atomization characteristics of shear-thinning liquid slurry discharging from fan spray nozzles were studied experimentally for spray painting applications. The effects of solid particle size and concentration on the properties (especially on the viscosity) of suspensions and mean drop size were examined by using model fluids. In the range of low particle concentration (below 3 wt%), the fluid viscosity was primarily determined by the particle size. On the other hand, in the range of high particle concentration (higher than 10 wt%), the agglomeration phenomenon and the oil absorption capability of solid particles played major roles in determining the fluid viscosity. In the high concentration region, which most of the paints belong to, the fluid became more viscous and the shear thinning behavior appeared more prominent as the particle concentration was increased. In this region, mean drop size(SMD) decreased more rapidly with the increase of the injection pressure. Also, SMD became larger with the higher particle concentration and the larger particle size.

• Journal of Advanced Marine Engineering and Technology
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• 제29권5호
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• pp.519-525
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• 2005

An electrochemical evaluation on the corrosion resistance for heavy anticorrosive paint(DFT:25um) was carried out for 5 kinds of heavy anticorrosive paints such as high solid epoxy(HE), solvent free epoxy(SE). tar epoxy(TE), phenol epoxy(PE). and ceramic epoxy(CE). Corrosion current densities obtained by Tafel extrapolation method from anodic and cathodic polarization curves didn't correspond with the values obtained by AC impedance measurement, however, the values of polarization resistance obtained from the cyclic voltammogram showed a good tendency corresponding well with the values of AC impedance measurement. Futhermore there was a good correlation against the corrosion resistance evaluation between passivity current density of the anodic polarization curve and diffusion limiting current density of the cathodic polarization curve. And corrosion resistance increased with corrosion potential shifting to noble direction. From the results discussed above. HE and CE had a relatively good corrosion resistance than other heavy anticorrosive paints.

• 한국응용과학기술학회지
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• 제21권3호
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• pp.197-203
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• 2004

Acrylic resins ($HSC_s$ : EA/EMA/2-HEMA/CLA) which contain 70% solid content were synthesized by the copolymerization of monomers (2-hydroxyethyl methacrylate, ethyl acrylate, and ethyl methacrylate) and functional monomer (caprolactone acrylate : CLA) which improves the crosslinking density and physical properties of films. The physical properties of the prepared acrylic resins (HSCs) containing CLA, are as follows : viscosity 245${\sim}$515 cps ; $M_n$ 2670${\sim}$2840 ; and conversions, 83${\sim}$91%, respectively. From the correlation of $T_g$ values, viscosities, and $M_n$ of the HSCs, it was found that viscosity and $M_n$ increased with $T_g$ value.