• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.461-469
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• 2010

Polyurethane adhesive is used in various fields as flexible packaging materials including a food packaging field. Therefore, the purpose of this study is synthesis of polyurethane adhesive which uses aliphatic isocyanate, and compares with aromatic isocyanate. The isocyanates for this test are toluene-2,4-diisocyanate(TDI), hexamethylene diisocyanate(HDI), 4,4-dicyclohexyl ethane diisocyanate($H_{12}MDI$), and isophorone diisocyanate(IPDI). And, the effect of any other diisocyanate are evaluated by several methods as for curing rate test, accelerate weathering test, and peel strength test. The polyurethane adhesive using curing catalyst and HDI has adhesion strength of about 560 g/15 mm between aluminium foil and nylon, about 1,520 g/15 mm between nylon and CPP. Those parameters are similar to polyurethane adhesive with TDI. Also, in case of curing rate, those are similar to TDI type polyurethane adhesive. Moreover, data of ${\Delta}E$ as color variation by QUV tester is equal to 4.12, as 48% against those of TDI type.

• International Journal of Industrial Entomology and Biomaterials
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• v.39 no.1
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• pp.9-13
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• 2019

In this study, 4 different types of GBR membrane were undergone for bio-degradability test; Silk mat from silkworm cocoon (TDI), silk mat from flatwise-spun (FS), collagen membrane (OssGuide), and dPTFE membrane (Cytoplast). Each material was segmented in 10.00 mm length and 0.3 mm thickness. The samples were put into the normal saline at $37^{\circ}C$ for 2 weeks. After that, yield strength and tensile strain were measured and compared them with those of before treatment. The morphology of the membranes was observed by SEM. Tensile strain of FS was significantly increased at 2 weeks' normal saline treatment (P=0.018). When compared to OssGuide, TDI and FS showed significantly higher tensile strain at 2 weeks' normal saline treatment (P<0.05). In the SEM images, there were no significant changes in Cytoplast, TDI, and FS after 2 weeks' treatment. However, OssGuide showed damaged surface after 2 weeks' treatment. In conclusion, both TDI and FS did not have any evidence of biodegradability at 2 weeks' observation in normal saline treatment. However, OssGuide showed more than 20 % decrease in yield strength and tensile strain.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.2
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• pp.95-102
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• 2013

Objectives: The aim of this study is to present an appropriate sampling method for individual exposure assessment based on a comparison of toluene diisocyanate (TDI) concentrations collected through different sampling methods by work process type. Methods: Two plants handling TDIs in the Incheon area were selected. The samplings were taken during respective processes of spray painting, drying, grinding, and foaming, in which the production of TDIs took on different forms. For the sampling methods for airborne TDIs, open-face cassette holder, modified 2-piece cassette holder, and impinger were used, and the sampling was performed simultaneously at the same locations. Results: The comparison of TDI collection concentrations by each process depending on the sampling method showed high concentrations in the order of the impinger, modified 2-piece cassette holder, and open-face cassette holder for spray painting and foaming. In all processes with the exception of drying, TDI collection concentrations were higher for sampling done with the modified 2-piece cassette holder than with the open-face cassette holder. Conclusions: Based on these results, the modified 2-piece cassette holder was found to be a more appropriate sampling method than the open-face cassette holder when taking individual samples of TDIs from spray painting, grinding, and foaming processes. In particular, for individual exposure assessment of the spray painting process, which features comparatively high collection concentrations compared to the other processes, the use of a modified 2-piece cassette holder is considered appropriate.

• Journal of the Korean Chemical Society
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• v.27 no.1
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• pp.58-65
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• 1983

The mechanical properties (tensile strength, 100% modulus and hardness) of the urethane elastomers prepared from hydroxyl terminated polybutadiene (HTPB), several low molecular weight diols (ethylene glycol, 1, 3-propane diol, 1,4-butane diol, 1,5-pentane diol and 1,6-hexane diol) and two kinds of diisocyanates(TDI: toluene diisocyanate, IPDI: isophorone diisomechanical properties were enhanced for the increases of the concentrations of the urethane group, as predicted. In case of TDI, when the mechanical properties of the elastomers were plotted patterns were observed, which can be explained by hydrogen bondings depending on the number of the methylene carbons. But the mechanical properties of the elastomers derived from IPDI had decreasing curves against the number of methylene carbons in low molecular weight diols, without the characteristic zigzag patterns.

• Toxicological Research
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• v.18 no.2
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• pp.175-181
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• 2002

Allergic contact dermatitis (skin sensitization) may be caused by a wide variety of chemicals. A murine local lymph node assay (LLNA) has been developed as an alternative to guinea pig models for assessing the contact sensitization potential of chemical. This study was carried out to evaluate the skin sensitization potential for chemicals in Balb/c mice by LLNA. Contact allergen, dinitrochlorobenzene (DNCB), respiratory allergen, toluene diisocyanate (TDI) and a weak allergen, $\alpha$-hexlycinnamaldehyde (HCA) were wed as positive chemicals and irritant, sodium lauryl sulfate(SLS) also wed as a reference chemical in this study. The weights of lymph node in the mice treated with DNCB, TDI, and HCA were increased compared to vehicle control. There was a significant increase in lymph node weight of mice treated with high concentration of SLS compared to vehicle control. The stimulation index (SI) of Lymph node cell in the mice treated with DNCB, TDI, and HCA revealed over three-fold increase compared to vehicle control by $3^H$-thymidine uptake. All allergens correctly identified in this LLNA study wing Balb/c mice. These results suggest that LLNA wing Balb/c mice could be a useful method for screening the allergenic potential of chemicals. The expression of IL-2 mRNA was slightly increased in draining auricular lymph node cell of the mice treated with TDI and HCA by RT-PCR. However the IL-2 levels in DNCB and SLS of treated animals were not significantly changed.

• Tuberculosis and Respiratory Diseases
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• v.39 no.6
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• pp.490-501
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• 1992

Background: Isocyanate is the most significant cause of occupational asthma in this country. The mechanism of isocyanate induced bronchoconstriction is unclear. Subjects and Method: To observe its immunologic and clinical findings, we performed methacholine bronchial challenge test (MBCT), toluene diisocyanate (TDI)-bronchoprovocation test (BPT) and RAST to TDI-, diphenylmethane diisocyanate (MDI)-, and hexamethylene diisocyanate (HDI)-human serum albumin (HSA) conjugate in 22 isocyanate-sensitive asthmatic workers. Results: BPT revealed early (11), dual (5), and late only (6) asthmatic responses. Their latent period ranged from 3 to 120 months (mean:45.9 months). Three cases (13.6%)showed a negative response on initial MBCT, but following MBeT performed 24 hours after TDI-BPT revealed the development of airway hyperresponsivenss. Twelve (54.5%) workers had increased specific IgE to TDI-HSA, seven (31.8%) had to MDI-HSA, and nine (40.9%) had to HDI-HSA conjugate. The prevalence of specific IgE was not associated with latent period, type of asthmatic responses, smoking, and atopic status. After 3 months' avoidance from workplace, airway hyperresponsiveness was improved in 10 (38.3%), among 12 followed cases. Conclusion: It is suggested that isocyanate can induce IgE-mediated bronchoconstriction in 59.1% of isocyanate-sensitive asthmatic workers. Isocyanate-induced asthma can occur even though MBeT showed a negative result, and measurement of the changes of airway hyperresponsivenss after isocyanate-BPT could be helpful to diagnose isocyanate-sensitive asthma.

• Journal of the Korean Applied Science and Technology
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• v.15 no.3
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• pp.77-84
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• 1998

Two-component polyurethane flame retardant coatings were prepared by blending phosphate-containing modified polyesters(PMPEs) and TDI-adduct. PMPEs were synthesized by polycondensation of dimethyl phenylphosphonate, a flame retardant component, with 1,4-butanediol, adipic acid, and trimethylolpropane. The content of dimethyl phenylphosphonate was varied 10, 15, and 20wt% for the reaction. Various physical properties of these new flame retardant coatings were comparable to non-flame retardant coatings. Coatings with 20wt% dimethyl phenylphosphonate did not burn during the vertical burning test.

• Journal of Environmental Science International
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• v.23 no.11
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• pp.1909-1918
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• 2014

In this experiment no solvent based polyurethane(PU) adhesives were prepared with the polyol, isocyanate, dioctyl phthalate(DOP), 2-hydroxyethylacrylate(2-HEA) and other acrylate monomers. The softenening point of the PU adhesives measured by Ring & Ball method were examined in the present study. And adhesion strength and mechanical properties such as tensile strength and 100% modulus of the PU adhesives were evaluated by Universal Test Machine. The experimental results showed that increase of both DPE-41, benzoylperoxide(BPO) and toluene diisocyanate(TDI) increased softenening point, adhesion strength, tensile strength and 100% modulus. However as DOP content increased sofenening point, adhesion strength decreased and tensile strength, 100% modulus also decreased.

• Journal of Environmental Impact Assessment
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• v.17 no.2
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• pp.143-151
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• 2008

As the NOAFL of copper based on liver toxicity in the human body is set and the TDI of copper is lower, it is necessary to strengthen the drinking water standard of copper according to toxic effects and the TDI of copper in humans. It is difficult to calculate the accurate drinking water standard because of the part of uncertainty for chronic effects of acute human with Wilson's disease and baby in the current studies. In order to improve the drinking water standard of copper considering of liver toxicity, it is desired to set the drinking water standard with concerning of the revising tendency in the foreign countries such as US, EC and WHO.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1734-1735
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• 2011

In case of inspection on aluminum castings, traditional RT (Radiographic Testing) method have been utilized for its advantages in interpretation, cost and perpetual storage. But it has disadvantages like time consumption in film processing, low efficiency in storage and environmental pollution. In this thesis, a DRS (Digital Radiography System) utilizing X-Ray TDI Camera (Time Delay and Integration Camera) is developed. Inspections on aluminum castings are performed using the developed Digital Radiography System, DRS and reviewed if newly developed system can substitute for the traditional method.