• Textile Coloration and Finishing
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• v.24 no.1
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• pp.79-90
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• 2012

This study surveys the characteristics of the PU/MWNT foaming film according to foaming conditions. For this purpose, firstly, 16 kinds of PU/MWNT forming films were prepared with 4 kinds of dispersion solutions (IPA/MWNT, DMF/MWNT, MEK/MWNT, and Toluene/MWNT) and 4 kinds of blowing agents (organic I, organic II, capsule, and inorganic). The electrical resistivity of these PU/MWNT foaming films according to the dispersion solutions and blowing agents were analysed and discussed with surface profile and cell morphology of measured by SEM. And secondly, 24 kinds of PU/MWNT foaming films were also prepared with 2 kinds of IPA dispersion solution contents and 3 kinds of blowing agents with variation of the blowing temperatures and film thickness. The physical properties of the PU/MWNT foaming films such as electrical resistivity (surface and volume) and triboelectricity with cell morphology were measured and discused through the quantities of IPA, blowing agent added and also physical conditions(temperature, thickness so on) for establishing optimum foaming conditions with good electrostatic dissipation.

• Journal of the Korean Wood Science and Technology
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• v.26 no.4
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• pp.43-49
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• 1998

The availability of large quantities of waste woods provides an impetus for investigating woody biomass potential uses. Polyurethane (PU) foams are prepared with reacting isocyanates and polyols, and are used. in various industry fields. Thus, lignocellulosic waste raw-materials are proposed as replacement for synthetic polyol to PU foam formulation. In this study PU foams were manufactured from liquefied woods, methanediisocyanate(MDI), catalyst, foaming stabilizer, and viscosity aids. The polyol content, isocyanate.hydroxyl group (NCO/OH) ratio, and water content were varied to evaluate their effects on the foaming and water absorption of the PU foams. Less than 400 Molecular weight. of polyethylene glycol(PEG) and 1 to 3 solvent to woody raw-material ratio were desirable for liquefying woody materials. Liquefying rate was increased with more than 3 % addition of inorganic and organic catalysts and raising reaction temperature more than $150^{\circ}C$. Addition of starch enhanced liquefying of woody materials. Fourty percents of starch resulted in about 90% liquefying rates. Foaming rates were increased with increasing moisture contents of liquefied wood. Moisture contents of 0.6% resulted in 5 time-foaming rates, and seven percents of moisture contents more than 30 time-foaming rates. But, an increase in water content may result in a decrease in cross-links between wood polyol and isocyanate, because the NCO/OH ratio is constant. Increasing moisture contents have significantly decreased density of PU foams. The optimum water content should be about 2.5% or less in this adopted condition.

• Polymer(Korea)
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• v.34 no.5
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• pp.442-449
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• 2010

Polyurethane(PU) prepolymer was synthesized from ethylene oxide/propylene oxide(EO/PO) random polyether polyol, toluene diisocyanate and chain extender such as ethylene glycol and 1,4-butanediol. PU foams having various compositions were fabricated from PU prepolymers with different hard segment contents(%) and mixed foaming solution of different compositions. PU foam from chain extender-introduced PU prepolymer and mixed foaming solution containing glycerin showed better mechanical property than other groups. Various PU foams were tested on their mechanical property, moisture vapor transmission rate, absorption speed, absorptivity, morphology and cell culture test. According to the test, the PU foam fabricated from chain extender-introduced PU prepolymer and mixed foaming solution containing optimum composition of F-68, glycerin and CMC was found to have the best property for wound dressing materials. From in vivo animal study, it was confirmed that above PU foam showed rapid wound recovery.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.281-292
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• 2014

Objectives: The aim of this case study is to verify the chemical exposure reductions for various chemicals by substituting the ingredients of raw materials in a polyurethane(PU) foaming industry. The PU foaming process was making various passenger car seats from chemicals such as toluene diisocinate(TDI), methylene bisphenyl isocyanate(MDI) and polyols. Methods: Basic process data and workers' health effects could be gathered by interviewing managers and reviewing previous exposure monitoring data. Amine, aldehyde and isocyanate chemicals were analyzed following the NIOSH-NMAM. Area sampling methods rather than personal sampling were introduced for this field investigation. Results: Two amines, triethylene diamine(TEDA) and N,N,N',N'-Tetramethyl-1,6- hexanediamine(TMHDA) were identified in raw polyol, cured PU foam and air. The average concentrations of TEDA and TMHDA showd less than 1 ppm by area sampling; however, that caused halovision among workers in PU-PAD process. Aldehydes and isocyanates were detected in the air while the concentrations were relatively low compare to occupational exposure limits. Successful raw material substitution from nonreactive amine to reactive amine could reduces air-borne amine and aldehyde levels by about 70%. Halovision had been disappeared successfully in the process. Conclusions: Several amines caused halovision among workers in PU-PAD process, especially during summer season in spite of relatively low levels. Combination of reactive amines into urethane foam could reduced vapor generation into air, which resulted in the elimination of eye troubles in the process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.607-612
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• 2019

The softness of the crashpad part is one of the important factors which affect the interior perceived quality of the vehicle interior. And while improving the softness of the crashpad part, every effort to lower the production cost has been going on. The PU foaming process for the crashpad part depends on the understanding of a lot of processes, tools and material properties. Therefore, to achieve the requirement of the customer for the interior part's visual quality, the integrated design techniques are investigated to correlate the processes, tool design, material design and the computer aided analysis. In this paper, IMG (In Mold Grain) designed concept is firstly developed to integrate the skin preforming, plastic injection molding of the substrate and the foaming process in a tool within reduced processes. Through the application of this technology, softness of crashpad is improved by 40% compared to the conventional vacuum molding method, and the existing process is reduced by 50% by integrating the injection process and the manufacturing process. And by integrating the injection mold and the skin mold and removing the foaming mold, the number of molds are reduced from 3 to 1, resulting in 20% reduction in the cost of applying a medium-sized passenger car.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.3
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• pp.81-87
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• 2009

Lightweight board has been used for manufacturing various fields of automotive interior trims for years. The GMPU board was constructed with glass fiber mat, honeycomb and polyurethane foamed using polyol and isocyanate materials which were sprayed by robot that is interlocked foaming machine. For more lightweight and cost reduction this paper shows how to optimize GMPU process parameters that related to foaming condition, robot position and robot velocity for polyurethane weight. The results show that flexural strength and modulus of board's specimens were evaluated by robot velocity and moving pattern. Based on that, a innovative process was developed for more lightweight and cost reduction.

• Journal of Adhesion and Interface
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• v.13 no.4
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• pp.163-170
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• 2012

Although ${\beta}$-cyclodextrin (${\beta}$-CD) has been used as medicine, agrichemical, food, cosmetic, antioxidant, anti-volatile agent, anti-hygroscopic agent, fading-protecting agent, and emulsifier due to its ability to form inclusion complex by enclosing another molecule (guest molecule), it has been restricted in practical application because of its low solubility in water and organic solvent. In this study, ${\beta}$-CD derivative as a new polyol with inclusion characteristics against Bisphenol A and cyclopropane, foaming agent for polyurethane (PU), and with improved solubility was synthesized, characterized and used to formulate rigid PU foam with better thermal conductivity and compressive strength compared to that from commercial polyols.

• Polymer(Korea)
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• v.25 no.4
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• pp.528-535
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• 2001

Polyurethane specimens were mainly composed of polyol, MDI, silicone surfactant, and water. The effects of ethylene glycol on the cell size, forming magnification, cream time, gel time, take free time, final free rising height, and reactive temperature were investigated. The cyclopentane was used for PU foam as a physical blowing agent. The components were hand-mixed at about 5000 rpm within 4 seconds at room temperature. The mixtures with various ethylene glycol contents were foamed in the wood mold. When the index of isocyanate was fixed, as the amount of ethylene glycol increased, cell size and thermal conductivity were decreased by about 5.1% and 14%, respectively.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.58-58
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• 2011

CNT 나노기술을 응용한 IT산업용 적층간지용 ESD(정전방전, Electrostatic Dissipation)PU 발포필름의 제조 가공기술 및 상품화 개발은 전자제품 패키지에 요구되는 쿠션성과 정전방전 기능을 갖는 폴리우레탄 발포 필름의 제조기술을 확립함으로써 가능 할 수 있다. 특히 IT산업용 필름제품이 개발되면 ESD 성능을 발휘하게 됨으로서 정전기 쇼크에 의한 각종 전자제품의 오작동이나 파손 방지가 가능하게 되어 포장재, 자동차, 전자제품의 하우징 등으로 사용될 수 있게 된다. 현재까지 ESD 기능을 부여하기 위해서 사용되는 충전재로는 금속섬유, 금속플레이크, 탄소섬유, 카본블랙 등이 있으며, 최근 탄소나노튜브를 응용한 연구가 많이 진행되고 있는데 탄소나노튜브는 직경이 수십nm, 종횡비 1000이상의 나노섬유형태로 서 전기전도성이 구리수준으로 알려져 있고 소량을 충전할 시 기계적 특성도 오히려 증대하는 장점을 가지고 있으며 전기적 특성으로는 상대적으로 낮은 나노튜브 함량에서는 ESD를 들 수 있고 높은 함량에서는 전자파 차폐성까지 기대되고 있다. 본 연구에서는 우수한 인장강도, 기계적 강도, 열적 안정성, 내약품성을 가지면서 습식 또는 용융공정을 통해 용이하게 시트, 필름, 코팅제를 제조할 수 있는 방수, 투습방수성을 가지는 유연재료인 폴리우레탄(PU) 1액형 PU에 MWNT 함량이 3wt%인 IPA/MWNT 분산용액을 PU 함량 대비 20, 30, 40파트로 함유시켜 $120^{\circ}C$에서 2분 건조시켜 제조한 그라운드 필름에 2액형 PU와 IPA/MWNT 분산용액에 발포제를 첨가하여 발포온도 140, 150, $160^{\circ}C$에서 5분간 건조시켜 시료 필름을 제조하였다. 제조된 필름의 전기전도성 측정은 부피저항과, 표면저항을 각각 측정하여 확인하였으며, 필름의 마찰 대전압은 E.S.T-7 마찰 대전압 시험기를 이용하여 표면 마찰 대전압과 반감기를 측정하여 확인하고, 필름의 물리적 특성은 인장시험기를 이용하여 breaking stress, breaking strain을 구하였다. 필름의 표면 특성은 영상 현미경 시스템을 사용하여 ${\times}1000$ 배율로 측정하여 분산특성과의 연관성을 확인하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.3089-3095
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• 2013

The headliner was made of polyurethane(PU) and glass fiber(GF) composite materials are widely used as a sound insulation material. A large amount of waste materials occurs as a by-product in the headliner manufacturing process. In order to efficiently reuse the headliner waste materials, separation process of the components are very necessary. According to the results of thermal analysis, weight loss showed increase in the order polyurethane foam> non-foaming polyurethane> non-woven fabric> 1st layer> glass fiber in the range of up to $400^{\circ}C$. Analysis of the DSC characteristics, HDPE, LLDPE, PP, and Master Batch by adding additives the wasted scrap. As a result, except for the PP, there was no exothermic transition due to the crystallization.