• Korean Journal of Materials Research
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• v.13 no.1
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• pp.18-23
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• 2003

Properties of Ag thick films fabricated by using low temperature curable silver pastes were investigated. Ag pastes were consisted of polymer resins and silver powders. Ag pastes were used for conductive or fixing materials between board and various electrical and electronic devices. Low temperature curable Ag pastes have some advantages over high temperature curable types. In cases of chip mounting, soldering properties were required for screen printed Ag thick films. In this study, four types of Ag pastes were fabricated with different compositions. Screen printed Ag thick films on alumina substrates were fabricated at various curing temperatures and times. Thickness, resistivity, adhesive strength and solderability of fabricated Ag thick films were characterized. Finally, Ag thick films produced using Ag pastes, sample A and B, cured at $150^{\circ}C$ for longer than 6 h and $180^{\circ}C$ for longer than 2 h, and $150^{\circ}C$ for longer than 1 h and $180^{\circ}C$ for 1 h, respectively, showed low resistivities of $10^{-4}$ $∼10^{-5}$ Ωcm and good adhesive strength of 1∼5 Mpa. Soldering properties of those Ag thick films with curing temperatures at solder of 62Sn/36Pb/3Ag were also investigated.

• Polymer(Korea)
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• v.35 no.2
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• pp.136-140
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• 2011

The plasma resistances of nitrile curable perfluoro elastomer (NT PFE) and peroxide curable PFE (PO PFE) after exposing to $NF_3$ and $O_2$ remote plasmas were investigated by analyzing weight loss and morphology of O-ring made of PFE. The compounds were designed following the typical formulations of O-ring/seal which were applied in semiconductor and LCD production site. They were blended by an open roll mill, and then, O-ring was finally made by hot press molding and oven curing. The weight loss was calculated and morphology was observed for each atmosphere and temperature by a digital weighing machine and SEM. As results, it was confirmed the weight loss and related morphology were meaningfully different according to the cure type of PFE, filler system, and the species of remote plasma.

• Clean Technology
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• v.23 no.2
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• pp.148-157
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• 2017

To prepare UV-curable polyurethane-acrylate oligomer, NCO-terminated urethane prepolymers with trimethylolpropane, [TMP; 0 (0), 0.1 (0.021) and 0.2 (0.043) mole (mole fraction)] as crosslinkable tri-functional chain extender were end-capped with pentaerythritol triacrylate [PETA; 2.0 (0.400), 1.7 (0.354) and 1.4 (0.304) mole (mole fraction)] with one hydroxyl group/three vinyl functionalities. The stable as-formulated UV-curable polyurethane-acrylates [stable mixtures of PETA-capped oligomer/reactive acrylic monomer diluents without/with heptadecafluorodecyl methacrylate (PFA; 0, 6 and 9 wt%)] were formed up to 0.2 (0.043) mole (mole fraction) of TMP content in the prepolymer, while homogeneous-mixing failed at 0.3 (0.068) mole (mole fraction), in which the crosslink density in NCO-terminated urethane prepolymer was too high to enable the formation of stable mixture. This study examined the effect of TMP/PETA molar ratio and heptadecafluorodecyl methacrylate (PFA) content (wt%) on the properties of UV-cured polyurethane-acrylates as marine antifouling coating materials. The properties of UV-cured polyurethane-acrylate were found to be significantly dependent on the crosslinkable TMP/PETA ratio and PFA content. With the increasing of the TMP and PFA contents, the contact angles increased, and consequently the surface tension decreased. The adhesion of algae/barnacles to PFA contained film samples were found to be sufficiently weak to allow their easy removal. These results suggest that the UV-cured samples containing PFA have strong potential as coating materials for antifouling applications.

• Journal of Adhesion and Interface
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• v.20 no.4
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• pp.140-145
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• 2019

In view of environmental considerations, the control of carbon dioxide (CO₂) and volatile organic compounds (VOCs) is one of important issues in the film and coating industries. Therefore, UV-curable system has been developed due to minimize emissions of VOCs and reduce CO₂ emission due to low energy consumption from fast curing. Also, biodegradable polymers economically are attractive because of environmental and economic concerns associated with huge waste plastics. In this study, UV-curable polyurethane acrylates with different compositions of biodegradable polylactide (PLA) diol and poly(ethylene glycol) as diols were synthesized and curing reaction of their end-capped acrylates was performed by UV exposure. Tensile strength, elongation, and Tg of the UV-cured polyurethane acrylates increased with PLA diol content in the diol while their hydrophilicity and thermal stability increased with the PEG content. These results indicated a property of UV-cured polyurethane acrylates could be controlled by environment-friendly diols.

• Elastomers and Composites
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• v.47 no.4
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• pp.318-328
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• 2012

In this study, the one-component curable polyurethane resin was manufactured using blocked isocyanate and hybrid technology. To prepare the one-component curable hybrid polyurethane, silica hybrids including hydroxyl group was synthesized, and the size, shape and distribution of hybrid particle in polyurethane resin were confirmed. Then the dissociation property, mechanical property and molding property of blocked isocyanate were investigated. The dissociation property of blocked isocyanate in one-component curable polyurethane became better as the heating temperature and treatment time increased. The synthesized silica hybrid had spherical appearance and size of 23~27 nm in diameter, and it was observed that the hybrid particles were homogeneously distributed in polyurethane structure. In the case of hybrid polyurethane, the mechanical property, anti-abrasion and thermal property were higher than those of general polyurethane, and it was observed that the mechanical property was maintained when the plasticizer was introduced.

• Journal of the Korean Graphic Arts Communication Society
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• v.18 no.1
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• pp.59-69
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• 2000

The characteristics of liquid crystal polymer composite(LCPC) films are possessed of large-area and flexible display, polarizer free, high contrast, wide angle of visual filed and high responsiveness. It is well known that the LCPC films consisting of a continuous LC phase embeded in a three-dimentional network of polymer matrix are formed by photopolymerization-induced phase separation. In this study, we have investigated the point that both liquid crystals and polymer having different properties have to coexiste as composed films. The purpose of this study has been the development of new application with liquid crystals and UV-curable monomers. In the results abtained on the miscibility of nematic liquid crystal and UV-curable resins, difunctional monomer HX-620 turned out to shows the best. From the results abtained on structures, electro-optical properties and dynamic visocoelasticity for LCPC films, the best mixing ratio of monomer to LC mixture were 3/7(photoinitiator; 4wt%) by weight, and this ratio has been provided the most thermal stability for LCPC films. In the results abtained on structure and discoloration properties of LCPC films, it has been demonstrated that consiste of a 8:2 mixture of chiral nematic liquid crystal and HX-620 has the greatest domain and it was the best discoloration.

• Textile Coloration and Finishing
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• v.20 no.2
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• pp.66-74
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• 2008

Effect of disperse dyeing on flame retardant finishing of PET fabrics via UV curing using three UV curable phosphorous-containing methacrylates and ammonium polyphosphate(APP) was investigated. The dye fixation and flame retardancy of PET fabrics did not change significantly with excellent durability to five laundering cycles irrespective of the dyeing and finishing sequence. However, the flame retardancy of Pekoflam-treated fabrics was lower than that of the UV treated and decreased substantially when heat treatment was carried out before the dyeing. The dyeability of the flame-retardant PET fabrics was not affected in the case of UV curing of the methacrylates alone. However, UV finishing after the dyeing caused significant decrease in K/S and ${\Delta}E$ due to changed refraction and inherent color of surface coating of the UV curable monomers and APP. Whereas the heat treatment with Pekoflam decreased both color fastness to laundering and sublimation, surprisingly the UV finish of PET fabrics before and after the dyeing increased the color fastness probably resulting from the presence of photopolymerized surface layer on the fabrics.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.10
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• pp.873-879
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• 2014

UV curable adhesives with different acrylic functionalities were synthesized for temporary bonding and debonding process in 3D multi-chip packaging process. The aim is to study various factors which have an influence on UV curing. The properties and curing behaviors were investigated by gel fraction, peel strength, probe tack, and shear adhesion failure temperature. The results show that the properties and curing behaviors are dependent on not only acrylic functionalities of binders but also UV doses and coating thickness.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.754-761
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• 2017

UV-curable hydrophilic coating solutions were prepared by mixing colloidal silica dispersed in alcohol with an acrylic monomer, pentaerythritol triacrylate (PETA). Hydrophilic coating films were also prepared by spin coating the hydrophilic coating solutions on PC substrates and UV curing for 10 minutes subsequently. The effect of the amount of colloidal silica in the coating solutions, which was varied from 10 g to 50 g, was investigated on the hydrophilic properties of UV-cured coating films. The results showed that the amount of colloidal silica had a great influence on the hydrophilic properties of UV-cured coating films and the coating film prepared with 30 g of colloidal silica showed a lowest contact angle of $37^{\circ}$ and an excellent pencil hardness of H.

• Journal of Adhesion and Interface
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• v.18 no.4
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• pp.159-165
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• 2017

In this study, we synthesized UV-curable urethane acrylates with different contents of BA, reactive diluent and characterized their physical properties such as thermal, mechanical properties, adhesive strength and flexibility resistance. From a result of DSC, Tg of polyol and acrylate resin were separated as the BA content increased more than 40%. Also, tensile strength, elongation and adhesive strength decreased with increasing the BA content. The UV-curable urethane acrylate with 40% BA has shown good flexibility resistance compared to other resin due to poor hardness and Tm of acrylate resin.