• Elastomers and Composites
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• v.34 no.5
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• pp.414-422
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• 1999

SBR, polyurethane and epoxy latex were separately blended with ethylene-vinyl acetate(EVA) emulsion In $0{\sim}50%$. EVA emulsion was not reacted with latexes in liquid phase and mixtures had good stroage stability. The viscosity of cement mixtures was elevated to 20,000cps in $0.5{\sim}2.0$ hours by mixing. The mixtures mixed with pigment represented high viscosity and showed higher viscosity as time goes by. Mixtures had higher hardness with mixing SBR than mixing epoxy or urethane. The hardness was suddenly increased over cement content 30%. showed pencil hardness $H{\sim}2H$ in $50{\sim}60%$. The increase of hardness in high solids was depended upon not only the condensation of latexs but also the coagulation and adhesion of cement particle.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.160-161
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• 2021

To prepare polyurethane coatings for top coatings of automobiles, acrylic resins containing 75% of solids were synthesized by a radical polymerization. The viscosity of the acrylic resins was increased with increasing OH values. Crosslinked acrylic-urethane clear coatings were obtained by curing reaction between the synthesized acrylic resins and hexamethylene diisocyanate(HDI) trimer(Desmodur N-3600). The physical properties from the following studies were carried out : viscosity(Zahn cup #2), adhesion, pensil hardness, and 60° specular gloss. Various properties of the acrylic-urethane clear coatings as top coatings of mobile coat were evaluated on the coating specimens. Adhesion property to a substrate, 60° specular gloss, and pencil hardness of prepared paint showed quite good properties.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.127-130
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• 2011

The duplex waterproofing construction method has been investigated to improve various problems (how to fix the sheet, breaking, air/water pocket, and cracks caused by different materials) of the existing rooftop exposed waterproofing construction method. By using fiber sheet, Net PE fabric, and thixotropy urethane with high viscosity, the waterproofing construction method is to glue the ground and waterproof course by circular dot. The method is also to construct the waterproof course with high hardness by using waterproof membrane coatings in upper hybrid system. By gluing the ground and the waterproof course by circular dot, the study is expected to be useful to minimize the simultaneous breaking in the waterproof course as tensile stress is buffer in case of the ground crackling. Also, since the waterproofing construction method is good at moving and emitting vapor from the ground, it is considered to be effective to minimize any damages caused by air/water pocket and get loose of the waterproof course.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.689-696
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• 2017

The practical applications of ordinary high-fluidity concrete have been limited due to several drawbacks, such as high hydration heat, high amount of shrinkage, and non-economic strength development. On the other hand, due to its advantages, such as improvement of construction quality, reduction of construction cost and period, the development of high-fluidity concrete is a pressing need. This study examined the properties of high-fluidity concrete, which can be manufactured on the low binders using a viscosity agent to prevent the segregation of materials. The optimal viscosity agent was selected by an evaluation of the mechanical properties of high-fluidity concrete among six viscosity agents. The acrylic type and urethane type viscosity agents showed the best performance within the range where no material separation occurred. The mechanical properties were evaluated to examine the optimal amount of AC and UT viscosity agent added by mixing two viscosity agents according to the adding ratio and blending them together with high performance water reducing agent. When the ratio of the AC : UT viscosity agents was 5:5, it was most suited for high-fluidity concrete with low binders by increasing the workability and effect of the reducing viscosity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.12
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• pp.1033-1038
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• 2002

In this study, urethane acrylate macromer was synthesized and it was used in a gel polymer electrolyte (GPE), and then its electrochemical performances were evaluated. LiCoO$_2$/GPE/graphite cells were Prepared and their performances depending on discharge currents and temperatures were evaluated. The precursor consisting of urethane acrylate (UA), hexanediol dimethacrylate (HDDA) and benzoyl peroxide (BPO) had a low viscosity relatively ionic conductivity of the gel polymer electrolyte with UA at room temperature and -20$\^{C}$ was ca. 4.5 $\times$ 10$\^$-3/S$.$cm$\^$-1/ and 1.7 x 10$\^$-3/ S$.$cm$\^$-1/, respectively GPR was stable electrochemically up to potential of 4.i V vs. Li/Li$\^$+/. LiCoO$_2$/GPE/graphite cells showed good a high-rate and a low-temperature performance.

• Journal of the Korean Applied Science and Technology
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• v.38 no.2
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• pp.476-487
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• 2021

To prepare acrylic resin coatings containing 70% of solids, we used n-butyl methacrylate(BMA), methyl methacrylate(MMA), 2-hydroxyethyl methacrylate(2-HEMA), and acetoacetoxyethyl acrylate(AAEA), caprolactone acrylate(CLA) as raw materials, the glass transition temperature(T_g) of acrylic copolymer was adjusted around 50 ℃. The viscosity and molecular weight of the acrylic resins was increased with increasing OH values. Di-tert-amyl peroxide was found to be the suitable initiator to get high-solids acrylic resins. The optimum reaction conditions found in the study are 5 wt% of initiator, 4 wt% of chain transfer agent, 4 hrs of dropping time, and 140 ℃ of reaction temperature. The structure of the synthesized resins were characterized by FT-IR and ¹H-NMR spectroscopy. Number average molecular weight of 1900~2600 and molecular wight distribution of 1.4~2.1 were obtained. Crosslinked acrylic urethane clear coatings were obtained by curing reaction between the synthesized acrylic resins and hexamethylene diisocyanate trimer(Desmodur N-3300), the equivalent ratio of NCO/OH was 1.2/1.0. The physical properties from the following studies were carried out: viscosity(Zahn cup #2), adhesion, drying time, pot-life, pensil hardness, and 60° specular gloss. Various properties of the acrylic urethane clear coatings were also evaluated on the coating specimens. Adhesion property to a substrate, drying time, pot-life, pencil hardness, and 60° specular gloss of prepared paint showed quite good properties. Futhermore, prepared paint containing 10% of CLA showed quite good properties for adhesion, low viscosity and high hardness.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.586-592
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• 2017

In this study, acrylic resins with solids content of 75% were prepared by addition polymerization of n-butyl acrylate (BA), methyl methacrylate (MMA), 2-hydroxypropyl methacrylate (HPMA) and acetoacetoxyethyl methacrylate (AAEM) monomers. At this time, the glass transition temperature ($T_g$) of the acrylic resin was changed to 20, 30 and $40^{\circ}C$, and the hydroxyl value (OH value) was changed to 60, 90 and 120. As a result, the viscosity of acrylic resin increased with increasing $T_g$ and hydroxyl (OH) value. The synthesized acrylic resin was designed to have a high cross-link density to maintain high elasticity and high durability. The crosslinked acrylic resin was used to prepare an acrylic urethane clear coating by curing reaction with a block isocyanate (Desmodur BL-3175). The physical properties of the clear paints were analyzed by measuring viscosity, adhesion, pencil hardness and $60^{\circ}$ specular gloss. Acrylic urethane clear coatings were prepared as specimens and evaluated for various properties to be applied as top coatings for coil coating. The prepared coatings were excellent in adhesion, excellent in $60^{\circ}$ specular gloss and pencil hardness, and eco-friendly.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.628-634
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• 2014

In this study, a new paint which is able to resist the cavitation erosion is tried to be developed by using urethane added with polyol such as poly propylene glycol(PPG), poly carbonate diol(PCD), polycaprolactone polyol (PCL-1), and poly caprolactone-tetramethylene gylcolether polyol(PCL-2). The new paint synthesized by adding polyol was characterized with physical properties and resistivity to cavitation erosion. Among polyol, the prepolymer added with PCD showed high hardness and wear resistance. However, due to too high in viscosity, the prepolymer added with PCL-1 was selected as a paint. The paint added with PCL-1 showed high resistivity to cavitation erosion and its surface was monitored by using Scanning Electron Microscope.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.236-237
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• 2021

In the waterproofing of the rooftop of reinforced concrete buildings, it is difficult to solve perfectly according to the proficiency of waterproofing materials, methods, and mechanics. Therefore, this study applies a Tricot Fabric Mesh to the behavior of the bottom concrete. In addition, it responds to the behavior of the concrete cracking, and the waterproofing and protective layer has developed a method to provide convenience for rooftop floor use by adhesion between the base and the waterproof layer with the use of high viscosity urethane to effectively move the surface deformation and surface vapor and install a airvent device on the wall.

• Journal of Conservation Science
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• v.22
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• pp.77-86
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• 2008

The pre-treatment for conservation must be needed for the exhumed historic sites. So, the study of conservation and restoration of historical sites has progressed favorably with using various polymers for solving upper problems. The problems which should be essentially solved for conservation of the exhumed historic sites are, however, using reinforcing agents that don't impair their original forms and sorting reinforcing agents on the lines of the historic sites' soil. These agents should be able to use without the effect of outer environments like marsh, winter time or temperature. In this work, we synthesized Epoxy resin and Epoxy hardener for the restoration of historical sites. These products have very good tension strength and adhesion strength and various physical properties that the users want. Particularly, these epoxy with high viscosity have good separation of between Epoxy final product and Urethane pre-surface.