• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2008년도 제33회 펄프종이기술 국제세미나
• /
• pp.47-70
• /
• 2008

Cost efficiency is today the primary requirement in the paper and board industry. This has led therefore, to a greater preponderance of products with specifically designed functionality to take account of current industry needs. Continually increasing machine coating speeds together with these new coating colour components have put more emphasis on the importance of the correct rheology and water retention of the coating colours to achieve good runnability and end product quality. In the coating process, some penetration of the aqueous phase, to the base paper or board must occur to anchor the pre-coating to the base or the topcoat to the pre-coat. The aqueous phase acts as a vehicle not only for the binder, but also for the other components. If this water or material penetration is not controlled, there will be excessive material shift from the coating colour to the base, before immobilization of the coating colour will stop this migration. This can result in poor machine runnability, unstable system and uneven coating layer, impacting print quality. The performance of rheology modifiers or thickeners on the coating color have tended to be evaluated by the term, "water retention". This simple term is not sufficient to explain their performance changes during coating. In this paper we are introducing a new concept of "material retention", which takes note of the total composition of the coating colour material and therefore goes beyond the concept of only water retention. Controlled material retention leads to a more uniform z-directional distribution of coating colour components. The changes that can be made to z-directional uniformity will have positive effects on print quality as measured by surface strength, ink setting properties, print gloss, mottling tendency. Optical properties, such as light scattering, whiteness and light fastness delivery should also be improved. Additionally, controlled material retention minimizes changes to the coating colour with time in re-circulation giving less fluctuation in quality in the machine direction since it more closely resembles fresh coating for longer periods. Use of the material retention concept enables paper and board producers to have more stable runnability (i.e. lower process costs), improved end product quality (i.e. better performance of used chemicals) and/or optimized use of coating colour components (i.e. lower total formulation cost)

• 한국정밀공학회지
• /
• 제18권4호
• /
• pp.121-128
• /
• 2001

This study has been performed to investigate formability of non-vinyl PCM(pre-coated metal)sheet. First, physical test of PCM sheets were tested to evaluate finish coating characteristic of PCM. And then, test equipment was made for friction test and three non-vinyl PCM sheets were tested by straight pulling method. This paper provides the results of the friction tests showing the influence of sheet surface texture and process conditions. It was found that the influence of contact pressure and speed had an effect upon the level of friction. Also using tests, the scratch resistance of a series of polyester coating has been investigated. This investigation aims to clarify the process conditions that prevent the scratch of PCM to form the good electrical appliances such as microwave oven, air conditioner and refrigerator etc.

• 한국응용과학기술학회지
• /
• 제30권4호
• /
• pp.672-678
• /
• 2013

Although the basalt fiber has superior fire-resistance and chemical resistance, it has many disadvantages in its applications. Generally, the tensile and loop strengths of basalt fiber were decreased with generated frictional heat during industial appplications. To solve this problem, polytetrafluoroethylene (PTFE) coating system was introduced and a sutable coating condition was evaluated. The basalt fiber was pre-treated with triethoxytrifluoropropylsilane (TMTFPS) at various pHs and then coated with PTFE dispersions with penetrating agent sodium bis(2-ethylhexyl)sulfo succinate (DOS-Na) to increase the tensile and loop strengths as well as to reduce the fibril during working. A universial testing machine (Instron Model 3366) was used to measure tensile and loop strengths. When the PTFE dispersion with 0.25 wt% of DOS-Na was coated on the surface of basalt fiber after pre-treating with 5 wt% of PTFE, the highest tensile and loop strengths were reached to 3.5 gf/D and 2.4 gf/D, respectively.

• 한국표면공학회지
• /
• 제45권2호
• /
• pp.70-74
• /
• 2012

In thermal barrier coating (TBC) systems, the life of the coating depends on thermally grown oxide (TGO) layer because most of the failure of TBCs occurs when TGO growth increases. In order to inhibit TGO growth, process was additionally carried out before the heat treatment of the TBC coating layer at $1200^{\circ}C$ in air. In the additional process, heat treatment in vacuum furnace of < $10^{-5}$ torr was conducted for 7 h and 14 h before the heat treatment. The area and length of TGO, as well as the crack length in the TBC were characterized using a scanning electron microscope (SEM). The TGO thickness and crack of specimens pre-heat treated in vacuum furnace were reduced by 45% compare to those heat treated in furnace. Consequently, pre-heat treatment in a vacuum furnace process lead to effective inhibition of growth of the TGO.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2006년도 춘계학술발표논문집
• /
• pp.124-131
• /
• 2006

It is well known that smoother surface in substrate for coating or converting can obtain better results. Generally paper substrate is taking machine calendar process in papermaking system to give more uniformity and to get better coating runnability. This paper was prepared to find better idea for obtaining smoother surface after precalendering precoated paper as a substrate of double coating system. It was shown precalendering had effect on roughness improvement for precoating layer but was difficult to say it was effected to supercalendering results for double coating. The porosity and ink evaluation with precalendered double coated paper is needed to identify more essential clue for precalendering effect.

• Corrosion Science and Technology
• /
• 제3권2호
• /
• pp.59-66
• /
• 2004

In construction of new ships and large steel bridges in Korea, pre-construction primers (PCP), also known as shop primer, are routinely used and retained as an integral part of the protective coating system. Retention of PCP's can significantly reduce building schedule and cost. Retaining PCP through the so-called "sweep blasting" procedure eliminates or minimizes the necessity of a second blast operation, thus shortening overall schedule as well as reducing labor cost and hazardous waste disposal cost. This study evaluates the feasibility of retaining PCP as the part of primer for high performance protective coating systems applied to ships' hull, bottom and ballast tanks. Upon proving that the retention of the PCP is a viable option, the process of coating application can he improved significantly in terms of cost and working schedule of new ships and large steel bridges. Results indicate that use of the PCP via sweeping blasting in conjunction with standard high performance protective coating systems does not degrade the overall performance of the coating systems. At the same time, it is also highly recommended that the secondary surface preparation should consist of grit blasting of weld burnt and other damaged areas to SSPC SP-IO grade (Sa 2.5 Gr.), Near White Blast Cleaning with proper application and attention to detail.

• 한국분말재료학회지
• /
• 제7권2호
• /
• pp.63-70
• /
• 2000

Thermal spray coating process has proven to be effective at producing hard, dense, wear resistance coatings on the relatively mild substrates. Among several spraying techniques, HVOF (High Velocity Oxygen Fuel) and plasma coating processes, which are preferentially used for the wear resistance application such as capstans, have been applied in this study. The effects of pre-treatment, it-process and post-treatment parameters on the wear and mechanical properties of WC+12%Co, Cr3C2 and Al2O3 powder coatings have been investigated and correlated with the microstructures. The results indicated that the carbide coating was more preferable to the oxide coatings and the post-treatments consisting of vacuum annealing and sealing on carbide coatings led to significant improvements in wear resistance, adhesive strength and coating phase stabilization over the other processing techniques in this application.

• 한국표면공학회지
• /
• 제35권1호
• /
• pp.53-63
• /
• 2002

Ni coating was carried out by pulse plating at room temperature. So, experimental conditions for Ni-coating were based on Watt's bath, and new additives(propionic acid) were introduced in the Watt's bath electrolyte as $H_3$$BO_3$ alternatives. By adding propionic acid, coating layer demonstrated a good adhesion and uniformity without special pre-treatment of the 316L stainless steel at room temperature. With a decrease of amount of propionic acid and applied average current density, cathode current efficiency increased. Also, edge effect was decreased with decreasing a peak current and increasing a pulse frequency in the same bath condition. It was found that the optimum condition for Ni coating was a current density of 10~20mA/$\textrm{cm}^2$ at below 500 mA peak current in the $5m\ell/\ell$ propionic acid solution.

• 설비공학논문집
• /
• 제11권6호
• /
• pp.725-732
• /
• 1999

It is usual to use hydrophilic-coated aluminum foil for evaporator fin of air-conditioners to reduce air flow resistance caused by the water droplets condensed on the fin surface. The major effect of a hydrophilic coating is to reduce the contact angle of the condensate and prevent bridging of the condensate between the adjacent fins. The performance of hydrophilic coating generally tends to be degraded as it is used since the coating material is washed down by the condensate. In the present work, several types of hydrophilic coatings were evaluated in terms of durability of hydrophilicity, corrosion resistance and heat resistance. Results showed that an improved hydrophilic coating of resin type presented superb qualify in terms of durability and corrosion resistance while having almost the same level of qualify in heat resistance compared with the others.

• 대한조선학회 특별논문집
• /
• 대한조선학회 2009년도 특별논문집
• /
• pp.18-23
• /
• 2009

After the installation of electric cables at block, PE(pre-erection) and hull stages, the coating stains on the electric cable sheath were unavoidably occurred by additional painting process. According to class rules paint or coating applied on the electric cables shall not adversely affect the mechanical, chemical of fire resistant characteristics of the electric cable sheath. However, there has not been quantitatively studied about the effect of coating stains on properties of sheath materials. In this study, we tried to investigate the effect of coating stains on the performance and deterioration of sheath materials by using FTIR, SEM analysis, flame retardant, high potential voltage and tensile test. The results sowed that coating stains, which were occurred during painting work on site could not adversely affect on the performance and deterioration of sheath materials.