• Journal of the Korean Applied Science and Technology
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• v.17 no.4
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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.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.257-260
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• 2000

The composite composed of glass fabric and BMI resin was fabricated using resin transfer molding(RTM) process. it will be used as a supporting plate of transformer coil for high speed train. To develop a RTM process, permeability of preform was measured and resin properties like a viscosity and gellation time were checked. A resin pre-heating system and a mold system were also designed and developed. Using a vacuum-assisted RTM process, the composite supporting plate was successfully fabricated.

• Journal of Integrative Natural Science
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• v.12 no.2
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• pp.29-34
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• 2019

In dental resin cement studies, viscosity is also an important factor in the adhesion of tooth defects and implants. This study used BisGMA and HPMA as the main ingredients, triethylene glycol dimethacrylate (TEGDMA) as a diluent, and benzoyl peroxide (BPO) as a photoinitiator. The physical properties of graphene oxide used as an additive for functionality were evaluated, and its use as a dental resin cement material was investigated.The rupture strength has the tendency to increase along with the increase of the ratio of graphene oxide that was added, which seemed to reflect the effect of the high strength property of graphene oxide. The flexural strength also has the tendency to increase when about 0.5% of graphene oxide was added the same as the increase of rupture strength.When graphene oxide was added, according to viscosity use, the utilization as high-quality dental resin cements will increase.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.147-148
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• 2006

A research on scaffold fabrication has been progressed in many research groups. However, the mechanical properties of existing biodegradable materials are still not satisfactory. But, PPF (poly (propylene fumarate)) has a good mechanical property in comparison to other biodegradable materials. Nevertheless, the viscosity of the synthesized PPF is too high to fabricate structures using micro-stereolithography. Therefore, the viscosity of the resin was made low by adding the diethyl fumarate and this material could be used in micro-stereolithography apparatus. Then, a photoinitiator was added for photo crosslinking of the DEF/PPF resin. 2.5D and 3D scaffolds were fabricated our system and curing characteristics of the resin were analyzed through the experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.738-742
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• 2005

Rapid Prototype has been used to design and Production of part in a variety of fields ; Car, Electronic products, Aviation, Heavy industry etc. Moreover development of hardware gave rise to use the method of Rapid Prototype more and more at high precision and complicated shapes. Expecially, to be using process of products that shapes of Micro-hole ; Cellular phones, Antennas, Jewels, Semi conductor cases. In case of Micro-shape, precision of the shape turns on various condition ; Laser size, Laminate height, scanning speed, overcure, viscosity of resin, etc. Sometimes breaks out the case that interner hole of shape is blocked by viscosity of resin. The phenomenon has solved easily to reduce viscosity of resin. But, in case of the method brings about the problem that strength goes down in actuality products hardening. This study on verify to change of shape of Micro-hole and makes the semiconductor case which has shape of Micro-hole by using resin of higher viscosity, scanning speed and overcure

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.269-272
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• 2005

Epoxy resins are gradually becoming some of the most important and versatile polymers in modem civil engineering. Because epoxy resins have some unigue properties, such as toughness, versatility of viscosity and curing conditions, good handling characteristics, high adhesive strength, inertness, low shrinkage compared to most other thermo-setting resins and concrete, and resistance to chemicals, they have found many applications in construction castings, repair materials, road or bridge deck pavements, coatings, and as structural or non structural adhesives. In this applications, epoxy resins are widely used for polymer concretes, grouting materials, injection glues, and sealants. In this paper, characteristics of deformation of repair material after repaired have been investigated by viscosity of repair material and the width of crack. It is believed that flexural strength of epoxy resin with low viscosity is high because tensile strength is high and elongation at break is low, fracture energy is low.

• 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.

• Transactions of Materials Processing
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• v.23 no.1
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• pp.41-48
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• 2014

The light guide plate has become the major component for the backlight module in general information technology products (e.g. mobile phones, monitors, etc.). High speed injection molding has been adopted for thin walled LGP giving advantages such as weight, shape, size, and reduction in production costs. In the current study, the rheological characteristics of high liquidity plastic resin PC(HL8000) were measured using a capillary rheometer to improve the reliability of the numerical analysis for high speed injection molding. With the measured viscosity and PVT of PC(HL8000), numerical analysis of injection molding was conducted using the simulation software(Moldflow). Filling time and deflection were predicted and compared with those of traditional PC resins(H3000, H4000). The results show that PC(HL8000) has significantly different rheological characteristics during high speed injection molding. Hence proper properties of the resin should be used to improve the accuracy of numerical predictions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1322-1329
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• 2018

In this paper, the reliability test of three kinds of epoxy resin for GIS Spacer, which is a high voltage based heavy electric machine, AC electrical treeing experiments were performed. Three types of epoxy resins, Araldite B41, CT 5531 CI and B46, have slight viscosity differences. An non-uniform electric field, E = 1149.4 kV/mm, as the needle to plate electrode, a power source with a frequency of 1 kHz was applied to the tree electrode for accelerated deterioration. The treeing phenomena of the three kinds of epoxy resin all initiated, propagated, and destroyed by the branch tree. Epoxy Resin B46 was 145 times longer than B41 and 53 times longer than CT 5531CI. I think that the choice of epoxy resin is very important in choosing high voltage heavy electric machine insulation materials.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.47-48
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• 2003

Dilute bubble suspensions are prepared by introducing carbon dioxide bubbles into polyol resin. The apparent shear viscosity is measured with a wide gap parallel plate rheometer. A numerical simulation for deformation of a single bubble suspended in a Newtonian fluid is conducted by using a finite volume method (FVM) where multigrid algorithms are incorporated. Transient and steady results of bubble deformation were obtained and were in good agreement with experimental results. At high capillary number, viscosity of the suspension increases as the volume fraction increases, while at low capillary number, the viscosity decreases as the volume fraction increases.