• Clean Technology
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• v.10 no.1
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• pp.19-25
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• 2004

The leather was fixed with various colors through the dyeing process in leather manufacturing. During the dyeing process, the amount of 30~50% dyestuff which were not bonded with leather drained with waste water. These dyestuff raise lots of environmental problems, so technology for improving the fixing effect, levelling effect and penentration effect with the use of small amount of dyestuff has been required. Also, insufficient color fastness level 2~3 grade for common natural leather needs to be improved at the same time. Accordingly, the use of ultrasound(us) in dyeing process has decreased the amount of dyestuff and obtained the smooth permeability effect. So, we could find that the reduction of amount of dyestuff in wastewater led to decrease in environmental trouble caused by leather waste water with severe contamination degree and improved fastness up to 0.5 grades.

• Journal of Adhesion and Interface
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• v.20 no.3
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• pp.96-101
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• 2019

In this study, the flame retardant and physical properties of the expandable graphite/polyurethane foam composites were considered by the addition of expandable graphite. The tensile strength of expandable graphite/polyurethane foam composites decreased with the content of the expandable graphite and the analysis of cell shape by SEM has shown that as the expandable graphite content increases, the cell becomes uneven and collapses. As the results of the compressive strength, density and air permeability tests, it was found that density and as the content of the expandable graphite increased, the compressive strength of the composites increased but air permeability decreased. When the amount of expandable graphite was added at 10 phr or higher, the foam has excellent flame retardation performance. Analysis of the degree of diffraction by X-ray diffraction (XRD) showed that as the content of the expandable graphite increased, the crystal peak of the graphite appeared near $2{\theta}=26^{\circ}$.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.2
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• pp.77-85
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• 1996

The study on the ripening of leather waste sludge was performed to vemistabilize the sludge effectively using a laboratory scale darkened wood box reactor ($10{\times}10{\times}20cm$). The acceptable feed conditions for earthworm of Eh, alkalinity were obtained in the 30th and 35th days, respectively. The value of pH was gradually decreased from 7.8 to 7.1 through the ripening time. The contents of heavy metals of the ripened sludge were estimated as lower levels compared to the other regulatory standards for compost. After the ripening time for 50days, the physico-chemical properties of the sludge were estimated as pH 7.1, water content 72%, redox potential 85mV, electrolytic conductivity $2,620{\mu}mhos/cm$ and alkalinity 450 ppm as $CaCO_3$, respectively. In the ripened sludge, survival rate of the earthworms for 50 days was about 75%, and the live weight increase rate was about 230% at the temperature range of $20{\sim}25^{\circ}C$. Moreover, hatching rate of the earthworm cocoons was about 87% and the highest value was obtained in the 20~30th days. From the above results, it was evaluated that leather waste sludge could be vermistabilized effectively by earthworms, when the sludge was ripened during 50 days.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.371-376
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• 1982

An experiment was conducted to determine the effects of sludges from leather and paper processing as sources of fertilizers on the rice. The results obtained are summarized as follows; 1. When 1,000kg of composts, 500kg of leather sludges and 500kg of leather sludge plus 100kg of $CaCO_3$, were applied per 10a, there were 7 to 10% of yield increase overthe non-treatment (check). When 1,000kg of paper sludge and 1,000kg of leather sludge plus 100kg of $CaCO_3$ were applied per 10a, there were 22 to 23% of yield increase over the check plot. 2. It was apparent that one of the reasons for increased yield. components such as number of spike and ripening ratio was due to the promotion of sludge decomposition by the $CaCO_3$. 3. The reason for the high ripening ratio and increased number of spike when paper sludge was applied might be due to the effects of high amount of nitrogen and phosphorous contained in paper sludge. 4. Effects of leather or paper sludges on the rice as organic fertilizer were highly appreciable, but further studies will be necessary for the effects of heavy minerals contained in the paper or leather sludges.

• Journal of Adhesion and Interface
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• v.23 no.2
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• pp.33-38
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• 2022

In this study, we report on the synthesis and properties of eco-friendly waterborne polyurethane (WPU) according to bio-polyol contents. It was successfully synthesized by the different polyester polyol (DT-1040) and castor oil based polyol (COP) ratios. The glass transition temperature (Tg) of the synthesized bio polyol based waterborne polyurethane was around -70 ℃ and -30 ℃, and it was confirmed that the Tg range was widened as the COP content increased. In addition, as the COP content increased, the tensile strength decreased, and optimum adhesive strength showed when DT-1040:COP ratio was 7:3.

• 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.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.3
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• pp.134-139
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• 2004

A study was made on the synthesis of a carbonate base nitrogen-free deliming agent using a non-phosgene compound applicable to the deliming process, which is one of the biggest sources of pollutant increasing the T-N concentration in the effluent from the leather making processes. And also studied on the possibility of using the agent in the deliming process. Through measurement of T-N, BOD, COD and SS in the effluent after the agent is used, contents of Ca and Cr and TS in the leather after the deliming process were measured, by which deliming efficiency, influences to the physical properties of the chromium tanned leather and reducing effects of T-N, BOD, COD and SS concentrations in the effluent could be confirmed. Thus an eco-friendly study has been conducted.

• Applied Biological Chemistry
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• v.44 no.4
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• pp.257-261
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• 2001

Leather (skin & hide) is a body organ, comprising 3 to 5% of the animals weight. The cross-section of a leather is composed of two major divisions: the epidermis or grain layer and the corium or split layer. The leather is naturally covered with bacteria and fungi, because it is a particularly rich source of a wide variety of microorganisms. Stains or coatings of different colours occur in patches or over large areas, depending on the type of mould spore infestation. We examined the antibiotic effect of leather after washing. Upon applying equal fungicide, antibiotic effects increased as follows: grain layer>middle layer>flesh layer. Antibiotic effect decreased with increasing frequency of washing. Decrease in antibiotic effect was lower in OITZ fungicide than in TCMTB and CMK fungicides. Sulfated fatliquor showed higher antibiotic effect than phosphated fatliquor.

• Clean Technology
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• v.14 no.3
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• pp.193-203
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• 2008

A surfactant is used to assist the effect of cleaning, dispersibility and adhesion during leather manufacturing process. Existing surfactant for that process includes many hydrophilic groups that may cause problem such as stain, bad water resistance and poor durability, etc. It is potential problem to make high-performance property for future leather market. In this study, we have synthesized the fluorinated surfactant of which property decreases surface tension, increases dispersion, cleaning effect and the better chrome absorption by the high bond energy of C-F to complement weakness that the present alkyl derivative surfactants have. Using fluorinated surfactant, we can confirm that dispersion is increased, chrome absorption ratio is augmented with high osmosis and coherence, chrome content in the tanning waste water is reduced, BOD and COD contents are diminished and physical characteristics are improved.

• Journal of Adhesion and Interface
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• v.23 no.3
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• pp.80-86
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• 2022

In this study, water-based acrylic tackifier with different contents of 1-dodecanethiol(n-DM), a chain transfer agent(CTA), were synthesized to improve the performance and adhesive properties of water-based acrylic pressure sensitive adhesive(PSA). In order to investigate the change in physical properties according to the amount of water-based acrylic tackifier added, 10/20/30 phr of water-based acrylic tackifier was added to the water-borne acrylic emulsion to measure the physical properties. The molecular weight and glass transition temperature(T_g) of the synthesized water-based acrylic tackifier tended to decrease as the content of n-DM increased. When a water-based acrylic tackifier was added to the water-borne acrylic emulsion, the peel strength and heat-resistance were increased. Also, when the water-based acrylic tackifiers were added at 10 phr or 20 phr, the best value was shown.