• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.17-22
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• 2011

The conventional coated paper has many functional problems for printed RFID tag. This study was carried out in order to evaluate the effect of coating color components on conductivity of printed coated paper. It has been well known that the efficiency of printed RFID tag is influenced by surface properties of substrate. The required properties for suitable substrate of printed RFID tag are high smoothness and waterproof property. In this study high grammage base paper surface sized with PVA was used. Coated paper was manufactured with five different formulations. Types of coating pigments and dosage of latex were varied. It was obtained high smoothness and also less binder demand with clay than GCC. On the other hand, suitable surface resistance and smoothness of coated paper for RFID tag was obtained with 20% of latex. Besides it shows the possibility of using coated paper for printed RFID tag.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.16-24
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• 2012

To characterize the coating structure, diverse methods such as mercury intrusion, nitrogen adsorption and oil absorption methods have been developed and widely employed. These indirect techniques, however, have some limitation to explain the actual coating structure. Recently microscopic observation methods have been tried for analyzing structural characteristics of coating layers. Preparation of the undamaged cross section of a coating layer is essential for obtaining high quality image for analysis. In this study, distortion-free cross-section of the coating layer was prepared using a grinding and polishing technique. The coated paper was embedded in epoxy resin and cured. After curing the resin block it was ground with abrasive papers and then polished with diamond particle suspension and nylon cloth. Polished coating layer was sufficient enough to obtain undamaged cross sectional images with scanning electron microscope under backscattered electron image mode. In addition, the SEM images allowed distinction of the coating layer components. Also S/B latex film formed between pigment particles was visualized by osmium tetroxide staining. Pore size distribution and pore orientation were evaluated by image analysis from SEM cross-sectional images.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.185-194
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• 2009

The autogenous shrinkage of high-performance concrete, including very-early strength latex-modified concrete(VES-LMC), is generally bigger than that of normal strength concrete because of the low water/cement ratio, high binder contents, and usage of superplasticizer. Mix. proportion of VES-LMC has low water/cement ratio(0.38), high cement content(390kg/m$^3$), and aid of latex(15% of cement weight). Thus, these factors of VES-LMC, rapid water self-dissipation and evaporation within 3 hours of concrete placement would increase the autogenous shrinkage. The purpose of this study was to evaluate the early-age shrinkage, thermal deformation and autogenous shrinkages of VES-LMC with retarder contents(retarder solids-cement ratio, by weight) using to secure working time in field. The experimental results showed that retarder contents do not affect of the maximum hydration temperature. Early-age expansion of VES-LMC was mostly caused by thermal expansion and partly by autogenous expansion. The autogenous shrinkage is decreased by increasing the retarder contents within this study. On the other hand, the usage of retarder should be decided carefully considering the field conditions because an excessive usage of retarder can cause handful early-age expansion.

• Journal of the Korean Applied Science and Technology
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• v.27 no.2
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• pp.216-221
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• 2010

Polyvinyl acetate (PVAc) prepared by emulsion polymerization has broad applications for additive such as paint binder, adhesive for wood and paper due to its low glass transition temperature which help to plasticize substrate resins. Since emulsion polymerization has a disadvantage that surfactant and ionic initiator degrade properties of the product polymer, poly (vinyl acetate-eo-ethyl acrylate) (VAc-EA) was synthesized using potassium persulfate as catalyst and polyvinylalcohol (PVA) as protective colloid to prevent the degradation. The copolymer latex product was internally plasticized and has enhanced adhesion, water resistance during VAc-EA emulsion polymerization. No coagulation and complete conversion occur with the reactant mixture of 10 mmol/L potassium persulfate, 10 mmol/L poly ( vinyl alcohol) (PVA 17). As the concentrations of PVA increase, the viscosity becomes increase.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.339-347
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• 2011

This study was carried out in order to manufacture the high quality coated paper. High quality coated paper includes not only present state but also the state of the future. So in this study, acrylic-styrene emulsion which polymerized in laboratory was compared with SB(Styrene-butadiene) latex during thermal aging. The coated paper with three different formulations which controlled the dosage of acrylic-styrene emulsion were prepared. The coated paper were thermally aged at $105^{\circ}C$ for 18days and the optical properties were measured. Brightness, whiteness and CIE L value were higher during thermal aging with increasing amount of acrylic-styrene emulsion. CIE $a^*$ value was higher and CIE $b^*$ value decreased with increasing amount of acrylic-styrene emulsion. These results indicate that high quality coated paper which has anti -thermal aging property can be manufactured with acrylic-styrene emulsion.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.327-338
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• 2011

This study was carried in order to manufacture the high quality coated paper. High quality includes not only properties of coated paper but also final print quality. In this study, new acrylic-styrene emulsion was polymerized in laboratory and compared with styrene-butadiene latex. Low-shear viscosity of coating color was decreased with increasing acrylic-emulsion dosage. WRV was increased with addition and decreased with substitution of acrylic-emulsion. Paper gloss, brightness and whiteness were increased and PPS and opacity was slightly decreased with acrylic-emulsion. Ink gloss was increased with using No. 3 acrylic-emulsion due to lower ink setting properties. However No.1, 2 emulsion shows opposite situation. Surface strength of coated paper was increased with using No. 3 acrylic-emulsion These results indicate that high quality coated paper can be manufactured with using No. 3 acrylic-emulsion.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2008.04a
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• pp.60-74
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• 2008

일반적으로 종이 도공의 바인더로 사용되는 라텍스는 입자경이 작을수록 도공층이 부동화 되기 전에 도공층 내에서 원지 혹은 도공층 표면으로의 이동 특성이 강해져서 최종 도공지의 인쇄적성에 다양한 품질의 변화를 보일 수 있다. 라텍스는 원지와 접촉하는 순간부터 원지의 특성에 따라 원지 방향으로 1차 마이그레이션이 일어나고 건조공정의 건조조건(IR-Infra Red 혹은 Hot Air Dryer)에 따라 도공층 표면으로의 2차 마이그레이션이 일어나며 이로 인해 도공층 내에서 Z-방향으로 바인더 분포가 불균일하게 분포하게 됨으로서 인쇄 모틀 현상에도 영향을 미치게 된다. 따라서 본 논문에서는 도공액의 농도와 라텍스의 입자경 그리고 건조조건에 따른 도공층의 구조변화가 최종인쇄적성에 미치는 상관성을 검토하였다.

• Textile Coloration and Finishing
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• v.35 no.3
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• pp.151-158
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• 2023

In this study, we investigated the durability properties of the recycled leather using shaving scrap with antioxidant. Recycled leather sheets were manufactured by mixing shaving scrap and NB latex as a binder. HALS(Hindered Amine Light Stabilizer) and UVA(UV absorbers) were used as antioxidant. Mechanical properties such as hardness, tensile strength, elongation, tear strength and abrasion resistance were measured. Light aging resistance was evaluated using UV lamp and the degree of discoloration of the recycled leather sheets using a gray scale. In addition, to evaluate heat aging and UV aging, the degree of discoloration of the recycled leather sheets over time was measured using colorimeter. Washing fastness was evaluated on the degree of dyeing of recycled leather sheets for six type of multi-fiber woven fabrics (Acetate, Cotton, Nylon-66, Polyester, Acryl, Wool). To determine whether hazardous substances were detected in recycled leather sheets, the contents of arylamine and Cr 6⁺ were evaluated. As a result, when used in combination with antioxidant, the heat aging and light aging of recycled leather were improved and hazardous substance were not detected.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.129-137
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• 2017

PURPOSES : The purpose of this study is to develop bridge deck concrete materials based on ordinary Portland cement concrete, and to evaluate the applicability of the developed materials through material properties tests. METHODS : For field implementation, raw material (cement, fine aggregate, and coarse aggregate) properties, fresh concrete properties (slump and air content), strength (compressive, flexural and bond strength) gain, and durability (freeze-thaw resistance, scaling resistance, and rapid chloride penetrating resistance) performance were evaluated in the laboratory. RESULTS : For the selected binder content of $410kg/m^3$, W/B = 0.42, and S/a = 0.48, the following material performance results were obtained. Considering the capacity of the deck finisher, a minimum slump of 150 mm was required. At least 6 % of air content was obtained to resist freeze-thaw damage. In terms of strength, 51.28 MPa of compressive strength, 7.41 MPa of flexural strength, and 2.56 MPa of bond strength at 28 days after construction were obtained. A total of 94.9 % of the relative dynamic modulus of elasticity after 300 cycles of freeze-thaw resistance testing and $0.0056kg/m^2$ of weight loss in a scaling resistance test were measured. However, in a chloride ion penetration resistance test, the result of 3,356 Coulomb, which exceeds the threshold value of the standard specification (1000 Coulomb at 56 days) was observed. CONCLUSIONS : Instead of using high-performance modified bridge deck materials such as latex or silica fume, we developed an optimum mix design based on ordinary Portland cement concrete. A test construction was carried out at ramp bridge B (bridge length = 111 m) in Gim Jai City. Immediately after the concrete was poured, the curing compound was applied, and then wet mat curing was applied for 28 days. Considering the fact that cracks did not occur during the monitoring period, the applicability of the developed material is considered to be high.

• Journal of Adhesion and Interface
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• v.21 no.3
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• pp.81-85
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• 2020

Shaving dust is a collagen fiber that is the leather waste occurred for thickness adjustment during the natural leather manufacturing process, and causes problems such as an environmental contamination because of a chromium (Cr) contained when it comes to reclaiming process. Various studies applying the shaving dust are currently being conducted in many countries across the world with an initiative by the EU. Of those applications, the bonded leather is being highlighted as a substitute for natural leather. Since the bonded leather, however, uses latex as a binder, accordingly it entails a high weight and a poor ventilation, which are deemed as disadvantages due to its dense internal tissues compared to other synthetic leathers. To address such disadvantages, this study employed the thermally expandable micro sphere to improve its air permeability and light weight by alleviating the internal structure. This is a study on the manufacturing of light bonded leather using the shaving dusts. In the study, the shaving dusts were forced to foam under 100~120℃ considering the heat resistance of collagen fiber after applying the thermally expandable micro sphere, and then the tendency was analyzed. In the analysis results, the most excellent foaming rate was exhibited when the shaving dusts were treated under 120℃ for 8 minutes and the variation of internal structure according to a foaming was observed through SEM analysis for the cross-section of the bonded leather.