• 접착 및 계면
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• 제24권2호
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• pp.69-75
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• 2023

최근 자기복원(self-recovery) 코팅층을 가진 자동차용 도장면 보호필름의 적용이 증대되고 있다. 본 연구에서는 poly(urea-urethane) hybrid 자기복원 코팅층을 가진 poly(vinyl chloride) 기재 보호필름에 대한 기본 물성에 대한 평가 결과를 보고한다. Poly(urea-urethane) 기반 코팅층을 구성하고 있는 주요 화합물의 비율과 코팅층의 두께 변화에 따른 자기복원성능을 확인하였으며, 색차 값 측정을 통해 내오염성능을 정량화 하였다. 또한, 소수성 첨가제로 외부 오염에 대한 표면특성을 향상시키기 위하여, 소량의 실리콘계 반응형 첨가제를 코팅 조성물에 함량에 따른 easy-cleaning 효과와 접촉각을 확인하였다. 마지막으로, poly(urea-urethane) 자기복원 코팅층을 가진 보호필름의 장기간 사용에 따른 변색 및 변형에 대한 가능성을 확인하고자 촉진 내후성 평가를 진행하였다.

• Macromolecular Research
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• 제14권6호
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• pp.634-639
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• 2006

Waterborne polyurethane (WBPU) adhesive with varying amounts of dimethylol propionic acid (DMPA) was synthesized by prepolymer process and blended with polyisocyanate hardener. The mean particle size of the WBPU dispersion decreased with increasing DMPA content. $^1H$ NMR spectroscopy confirmed the formation of allophanate bonds and biuret bonds due to the reaction of hardener NCO with urethane/urea groups. The optimum NCO content with the greatest adhesive strength was dependent on the total content of urethane/urea groups in the WBPU molecules. The optimum NCO content increased with increasing number of urethane groups (DMPA content). The adhesion strength of WBPU adhesives was maximized at a molar ratio of hardener NCO to urethane/urea of about 0.28.

• Fibers and Polymers
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• 제3권3호
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• pp.97-102
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• 2002

A series of waterbome poly(urethane-urea) anionomers were prepared from isophorone diisocyanate (IPDI), polycaprolactone diol (PCL), dimethylol propionic acid (DMPA), ethylene diamine (EDA), and triethylamine (TEA), NaOH, or Cu($(COOCH_3)_2$) as neutralizing agent. This study was performed to decide the effect of neutralizing agent type on the particle size viscosity, hydrogen bonding index, adhesive strength, antistaticity, antibacterial and mechanical properties. The particle size of the dispersions decreased in the following order: TEA based samples (T-sample), NaOH based samples (N-sample), and Cu($(COOCH_3)_2$) based sample (C-sample). The viscosity of the dispersions increased in the order of C-sample, N-sample, and T-sample. Metal salt based film samples Of and C-sample) had much higher antistaticity than TEA based sample. By infrared spectroscopy, it was found that the hydrogen bonding index (or fraction) of samples decreased in the order of T-sam-pie, N-sample, and C-sample. The adhesive strength and tensile modulus/strength decreased in the order of T-sample, N-sam-pie, and C-sample. The C-sample had strong antibacterial halo, however, T- and N-samples did not

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1997년도 추계총회 및 학술발표회 논문집
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• pp.135-139
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• 1997

• Elastomers and Composites
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• 제53권2호
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• pp.86-94
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• 2018

The effect of the NCO index and catalyst type on the thermal stability of poly(urethane-isocyanurate) (PUIR) foams was investigated to identify a method for enhancing the flame resistance of PUIR. PUIR foams were prepared using 4,4-diphenylmethane diisocyanate (MDI) and [(diethylene glycol)adipate]diol, which were synthesized by esterification of adipic acid and diethylene glycol. Dabco K-15, Dabco TMR-30, and Toyocat RX-5 were used as the catalysts for trimerization and gelation. The amount of urea and isocyanurate groups in PUIR was semi-quantitatively determined by normalizing their absorbance with the phenyl absorbance measured by FT-IR. The normalization data showed that Dabco TMR-30 effectively generated isocyanurate groups in PUIR. As a result, Dabco TMR-30 effectively raised the decomposition temperature and increased the 800 K and 900 K residues of the PUIR foam synthesized with an NCO index of 200.

• 폴리머
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• 제38권6호
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• pp.720-725
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• 2014

Hydride terminated polydimethylsiloxane과 allyl amine을 hydrosilylation 반응으로 aminopropylpoly-dimethylsiloxane을 합성하고, 이를 hexamethylenediisocyanate(HDI)의 고리화 반응으로 제조된 cyclic HDI trimer와 반응시켜 urea결합으로 결합된 polydimethylsiloxane 변성 urea을 제조하였다. Polydimethylsiloxane 변성 urea의 말단에 있는 isocyante기와 2-hydroxyethylmethacrylate를 반응시켜 말단에 multi acrylate기가 도입된 polydimethylsiloxane 변성 urea/acrylate(PUA)를 제조하였다. 제조한 화합물의 구조를 FTIR, $^1H$ NMR로 확인하였으며, PUA에 아크릴계 단량체, 광 개시제, 용매 등을 여러 가지 조성비로 혼합하여 코팅 액을 제조하였으며 이를 PET 필름에 도포하고 UV을 조사하여 고경도의 유연성을 갖는 코팅 막을 제조하였다. 제조한 코팅 막의 연필 경도는 3H, 접촉각은 $82^{\circ}$, bendability는 $7{\phi}$까지 scratch가 발생하지 않았다.

• Journal of Photoscience
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• 제10권1호
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• pp.97-104
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• 2003

The excitation wavelength dependence of laser ablation dynamics of an azobenzene-containing urethane-urea copolymer film was investigated by measuring the laser fluence dependence of etch depth, transient absorbance change at each excitation wavelength, and transient absorption spectra. Moreover expansion/contraction dynamics was studied by applying nanosecond time-resolved interferometry. The threshold was determined at several excitation wavelengths from etch depth measurement, while time-integrated absorbance was obtained under excitation conditions. The photon energy required to remove the topmost of surface layer of the film did not .depend on excitation wavelength, and the penetration depth of excitation pulse dominated the etch depth. When the excitation wavelength was longer than 500 nm, permanent swelling was clearly observed but not for shorter wavelength excitation. In the latter case, photoisomerization occurred during excitation and the following photoreduction may play an important role. On the basis of the observations made in this study, a photochemical and photothermal mechanisms can explain mostly the short and long wavelength excitation results, respectively.

• Journal of the Korean Wood Science and Technology
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• 제47권2호
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• pp.200-209
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• 2019

To improve the water resistance of melamine-urea-formaldehyde (MUF) resins, different levels of blocked polymeric 4,4 diphenyl methane diisocyanate (B-pMDI) were blended with MUF resins to prepare B-pMDI/MUF hybrid adhesives, and their adhesion performances were evaluated for the surface lamination of fancy veneer on plywood. FT-IR spectra showed that the de-blocked -NCO groups reacted with the -OH of hydroxymethyl groups of the MUF resins to form urethane bonds at 2% B-pMDI/MUF, which was detected before and after their hydrolysis. The mass loss after the hydrolysis consistently decreased as the B-pMDI level increased, indicating an improvement in the water resistance. As the B-pMDI level increased, the activation energy of hybrid adhesives decreased, which improved the reactivity of the hybrid adhesives. Additionally, the water resistance improvement of the hybrid adhesives increased the tensile shear strength of the surface laminated plywood in semi-water proof and water-proof by 23 % and 8 %, respectively, at 2% B-pMDI level. This was likely due to the urethane linkages in the hybrid adhesives. However, the formaldehyde emission from plywood panels bonded with the hybrid adhesives increased in the dry state, indicating incomplete curing of the hybrid adhesives.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2009년도 학술발표대회
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• pp.63-64
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• 2009

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1998년도 가을 학술발표회논문집
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• pp.162-165
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• 1998

Characteristics of microcapsule wall depend on chemical and physical condition in procedure such as type and concentration of constituent and microencapsulation methods, thus, if the other process conditions are same, they depend on mainly types of wall-forming materials. Isocyanates used in this study are very important constituent as hard segments preparing urethane or urea by reaction with alcohol or amine. (omitted)