Thermal Decomposition Behavior of Blocked Diisocyanates Derived from Mixture of Blocking Agents

Lee Jung Min,Subramani Sankaraiah,Lee Young Soo,Kim Jung Hyun The Polymer Society of Korea 2005 Macromolecular Research Vol.13 No.5

To improve the performance and reduce raw material costs, blocked isocyanates were prepared with mixture of blocking agents in many industries. Three blocked isocyanates (adducts) namely $\varepsilon$-caprolactam/benzotriazole-blocked 4,4'-diphenylmethane diisocyanate (MDI), toluene-2,4-diisocyanate (TDI) and 4,4'-dicyclohexyl-methane diisocyanate ($H_{12}$MDI) were synthesized. Six reference adducts were also prepared by blocking MDI, TDI, and $H_{12}$MDI with $\varepsilon$-caprolactam ($\varepsilon$-CL) or benzotriazole. The reactions were carried out in acetone medium and dibutyltin dilaurate (DBTDL) was used as a catalyst. The progress of the blocking reaction was monitored by IR spectroscopy. De-blocking temperatures (dissociation temperatures) of these adducts were studied using DSC and TGA and the results were correlated. As expected, the thermal analysis data showed that de-blocking temperature of blocked aromatic isocyanates was lower than that of the blocked aliphatic isocyanates. The low de-blocking temperature of blocked aromatic isocyanate could be due to electron withdrawing benzene ring present in the blocked isocyanates. It was also found that benzotriazole-blocked adducts de-blocked at higher temperature compared with $\varepsilon$-CL-blocked adducts.

1액 경화형 하이브리드 폴리우레탄 탄성체의 열적, 물리적 특성에 관한 연구

목동엽 ( Dong Youb Mok ),김인수 ( In Soo Kim ),김동호 ( Dong Ho Kim ),김구니 ( Gu Ni Kim ) 한국고무학회 2012 엘라스토머 및 콤포지트 Vol.47 No.4

본 연구에서는 blocked isocyanate와 하이브리드 기술을 이용해서 1액 경화형 폴리우레탄 탄성체를 제조하였다. 1액 경화형 하이브리드 폴리우레탄의 제조를 위해서 hydroxyl group을 포함하는 실리카 하이브리드를 합성하고 입자크기, 형태 및 탄성체 내의 하이브리드 입자분포를 확인하였다. 또한, 열해리특성, 기계적 물성, 성형특성을 조사하였다. 1액 경화형 폴리우레탄 탄성체의 열해리 특성을 평가한 결과 온도가 높을수록, 열처리 시간이 길어질수록 blocking된 isocyanate의 해리가 더 잘 진행되었다. 합성된 실리카 하이브리드는 직경이 23~27 nm이고 구형이었으며 하이브리드 폴리우레탄의 단면을 FE-SEM과 EDS를 사용해서 분석한 결과 하이브리드 입자가 폴리우레탄 분자구조 내에 잘 분산되어있는 것을 확인하였다. 하이브리드 폴리우레탄의 경우에는 하이브리드를 포함하지 않는 폴리우레탄 탄성체에 비해 기계적물성, 내마모성 및 열적특성이 향상되었으며 가소제를 사용하는 경우에는 물성의 변화가 거의 없는 것으로 확인되었다. In this study, the one-component curable polyurethane resin was manufactured using blocked isocyanate and hybrid technology. To prepare the one-component curable hybrid polyurethane, silica hybrids including hydroxyl group was synthesized, and the size, shape and distribution of hybrid particle in polyurethane resin were confirmed. Then the dissociation property, mechanical property and molding property of blocked isocyanate were investigated. The dissociation property of blocked isocyanate in one-component curable polyurethane became better as the heating temperature and treatment time increased. The synthesized silica hybrid had spherical appearance and size of 23~27 nm in diameter, and it was observed that the hybrid particles were homogeneously distributed in polyurethane structure. In the case of hybrid polyurethane, the mechanical property, anti-abrasion and thermal property were higher than those of general polyurethane, and it was observed that the mechanical property was maintained when the plasticizer was introduced.

내구성 향상을 위한 은나노와 이소시아네이트가 포함된 소프트 콘택트렌즈의 물성에 관한 연구

조선아,성아영 대한시과학회 2013 대한시과학회지 Vol.15 No.1

목 적 : 본 연구는 furfuryl isocyanate를 은 나노 물질(Ag nanoparticle)과 기존의 하이드로젤 콘택트렌즈 재료와 공중합 하였으며, 제조된 콘택트렌즈의 물리적 특성을 비교하고, 내구성이 높은 콘택트렌즈 고분자로서의 활용성을 알아보았다. 방 법 : 교차결합제인 EGDMA(ethylene glycol dimethacrylate)와 HEMA(2-hydroxyethyl methacry‐late), MMA(methyl methacrylate), MA(methacrylic acid) 그리고 개시제인 AIBN(azobisisobutyronitrile)과 함께 공중합 하였다. 결 과 : 생성된 고분자의 물리적 특성을 측정한 결과, 함수율 28.98~34.31%, 굴절률 1.441~1.453, UV-B 투과율 33.2~72.0%, 접촉각 57.65~79.00° 그리고 인장강도의 경우 0.340~0.713kgf 범위의 분포를 나타내었다. 또한 은 나노 물질 1%에 furfuryl isocyanate를 첨가할수록 UV-B 투과율 저하와 인장강도가 증가한 결과를 보였다. 결 론 : 본 실험결과로 볼 때 생성된 공중합체는 내구성이 좋고 자외선 차단 효과가 있는 렌즈 재료로 유용하게 활용될 것으로 기대된다. Purpose : In this study, we compared the copolymer produced with the furfuryl isocyanate and Ag nanoparticle with previous hydrogel contact lens materials and measured the properties of the produced contact lens in order to experiment whether the material is suitable for contact lens materials with high durability. Methods : For copolymerization, furfuryl isocyanate with the cross-linkerEGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), MMA(methyl methacrylate), MA(methacrylic acid), Ag nanoparticle and the initiator AIBN(azobisisobutyronitrile) were used. Results : Measurement of the physical properties of the copolymerized material showed that the water content, refractive index, UV-B transmittance, contact angle and tensile strength were in the range of 28.98~34.31%, 1.441~1.453, 33.2~72.0%, 57.65~79.00° and 0.340~0.713kgf, respectively. Conclusions : Based on the results of this study, the produced copolymer can be estimated to be suitable for use as hydrogel contact lens material for high durability and uv-blocking.

이중경화형 blocked isocyanate를 활용한 클리어코트 소재의 열경화 거동 및 기계적 물성 분석

문호연,정인조,박준영,노승만,정현욱 한국공업화학회 2021 한국공업화학회 연구논문 초록집 Vol.2021 No.-

내구성 향상을 위한 은나노와 이소시아네이트가 포함된 소프트 곤택트렌즈의 물성에 관한 연구

조선아,성아영 대한시과학회 2013 대한시과학회지 Vol.15 No.1

목적: 본 연구는 furfuryl isocyanate를 은 나노 물질(Ag nanoparticler)과 기존의 하이드로젤 곤택트렌즈 재료와 공증합 하였으며, 제조된 콘택트렌즈의 물리적 특성을 비교하고, 내구성이 높은 콘택트렌즈 고분자로서의 활용성을 알아보았다. 방법: 교차결합제인 EGDMA(ethylene glycol dimethacrylate)와 HEMA(2-hydroxyethyl methacry-Late), MMA(methyl methacrylate), MA(merhacrylic acid) 그리고 개시제인 AIBN(azobisisobutyronitrile)과 함께 공증합 하였다. 결과: 생성된 고분자의 물리적 특성을 측정한 결과, 함수율 28.98~34.31%, 굴절률 1.441~1.453,UV-B투고율 33.2~72.0%, 접촉각 57.65~79.00° 그리고 인장강도의 경우 0.340~0.71kgf 범위의 분포를 나타내었다. 또한 은 나노 물질 1%에 furfuryl isocyanate를 첨가할수록 UV-B 투과율 저하와 인장강도가 증가한 결과를 보였다. 결론: 본 실험결과로 볼 때 생성된 공중합체는 내구성이 좋고 자외선 차단 효과가 있는 렌즈 재료로 유용하게 활용될 것으로 기대된다. Purpose: In this study, we compared the copolymer produced with the furfuryl isocyanate and Ag nanoparticle with previous hydrogel contact lens materials and measured the properties of the produced contact lens in order to experiment whether the material is suitable for contact lens materials with hugh durability. Methods: For copolymerization, furfuryl isocyanate with the cross-linkerEGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethel methacrylate), MMA(methyl methacrylate), MA(methacrylic acid), Ag nanoparticle and the initiator AIBN(azobisisobutyronitrile) were used. Results: Measurement of the physical properties of the copolymerized material showed that the water content, refractive index, UV-B transmittance, contact angle and tensile strength were in the range of 28.98~34.31%, 1.441~1.453, 33.2~72.0%, 57.65~79.00 ° and 0.340~0.713kgf, respectively. Conclusions : Based on the results of this study. The produced copolymer can be estimated to be suitable for usw as hydrogel contact lens material for high durability and uv-blocking.

Effect of isocyanate crosslinkers blocked with amine derivatives on rheological and crosslinking characteristics of automotive clearcoats

Young-Gun June,정인조,Tae Hee Lee,하미란,Seung Man Noh,정현욱 한국유변학회 2021 Korea-Australia rheology journal Vol.33 No.1

Isocyanate crosslinkers with blocking agents based on various amine derivatives were newly synthesized for automotive clearcoat applications. Amine-based blocking agents were prepared by varying the alkyl substituent attached on both sides of the main nitrogen atom (named DEA, DiPA, NtBEA, and NtBiA) to modify their deblocking feature in blocked isocyanates (BIs) and curing reaction under thermal curing conditions. Curing properties of clearcoats containing amine-based BIs were characterized at the normal curing temperature of 150°C and were compared with those by the commercialized BI, Desmodur® PL350. The dissociation ability of the amine-based BIs was interpreted using the density functional theory (DFT) simulation under their optimized geometric configurations. The urethane reaction between isocyanate group in BIs and hydroxyl group in a hydroxyl-functionalized polyol binder within clearcoats was confirmed from the OH stretching absorbance data via Fourier-transform infrared (FT-IR) spectrometer. The real-time crosslinking dynamics of various clearcoats with amine-based BIs were comprehensively investigated using rotational rheometer and rigid-body pendulum tester. The surface mechanical properties of fully-cured clearcoat films were measured by nano-indentation and nano-scratch testers to address the crosslinked network formation caused by amine-based BIs. It is demonstrated that the amine-based BIs could be favorably applied to thermal curing process of clearcoats, based on their reactivity and curing performance.

Synthesis and three dimensional pattern finishing properties of blocked isocyanate prepolymers

Hak Yong Kim,Fan-Long Jin,Un-Soo Lee,박수진 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.2

Two kinds of blocked isocyanate prepolymers (BIPs), BIP-S and BIP-H, were synthesized, and three dimensional pattern (3D) finishing properties of BIPs were investigated with several techniques. As a result, the BIP-H exhibited higher glass transition temperature, tensile strength, and tensile modulus than did BIP-S. The combination of two kinds of antioxidants resulted in good performance that prevented yellowing at high temperature and exposure to sunlight. 3D pattern finished cotton fabrics coated with BIP-S showed a higher transparency than that of non-coated cotton fabrics. Both cotton fabrics coated with BIP-S and those coated with BIP-H showed excellent repellency to alkali solution.

반응성 작용기를 갖는 마이크로 캡슐의 제조 및 분석

박연흠,고성욱,김영준 한국섬유공학회 2000 한국섬유공학회지 Vol.37 No.12

Functional polyurea microcapsules were prepared by the conventional interfacial addition polymerization utilizaing 2,4-toluenediisocyanate dimer. The inner-blockedisocyanate(isocyanate dimer) can be used to prepare microcapsules having latent functionality that can be cleaved at high temperature to generate isocyanate functional groups. The particle size of the microcapsules obtained was a function of the agitation speed and the concentration of surfactants. Average particle diameters were in the range of 10 to 30 ${\mu}{\textrm}{m}$. The oil-containing polyurea microcapsules of which average particle size of 10${\mu}{\textrm}{m}$ were obtained at 4000 rpm and 3% surfactant concentration. Both the DSC thermogram and FTIR spectroscopic data showed that the uretdione ring was opened and then blocked isocyanates were reactivated at an elevated temperature of 25$0^{\circ}C$.

Characteristics of dual-curable blocked isocyanate with thermal radical initiator for low-temperature curing of automotive coatings

Jung, Kevin Injoe,Kim, Beomjin,Lee, Dong Geun,Lee, Tae-Hee,Choi, Seo Yeon,Kim, Jin Chul,Noh, Seung Man,Park, Young Il,Jung, Hyun Wook Elsevier 2018 Progress in organic coatings Vol.125 No.-

<P><B>Abstract</B></P> <P>Dual-curable blocked isocyanate with a thermal radical initiator (BL-Tri-cHD) was designed and synthesized to perform low-temperature curing of automotive coatings. BL-Tri-cHD can simultaneously react with both unsaturated CC double bonds for free-radical polymerization and hydroxyl groups for the urethane reaction in hydroxyl-functionalized urethane methacrylate oligomers (HFUMO) under mild thermal curing conditions. The dual crosslinking behavior and mechanical properties of HFUMO-based coatings using BL-Tri-cHD were compared with those of a commercial blocked isocyanate thermal crosslinker (Desmodur® BL-PL350). The onset temperature for initiating cured by BL-Tri-cHD was about 68 °C, confirming faster crosslinking at relatively lower temperature than BL-PL350, which initiated curing at 140 °C. To quantitatively evaluate the properties of cured coatings, a nano-indentation was made in the surfaces of clearcoat films cured at 150 °C, 130 °C, and 120 °C. Films cured using BL-Tri-cHD and BL-PL350 at 150 °C exhibited similar indentation patterns. The indentation curves for the films with BL-Tri-cHD cured at lower curing temperatures such as 130 °C and 120 °C showed favorable penetration depth profiles similar to the sample cured at 150 °C, whereas the films with BL-PL350 cured below 150 °C had a less dense network structure, resulting in a deeper penetration depth than the sample cured at 150 °C. Therefore, we report that dual-curable BL-Tri-cHD demonstrates promising performance in automotive coating applications and possesses the ability to form highly crosslinked networks, even at low curing temperatures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dual-curable blocked isocyanate with a thermal radical initiator was synthesized. </LI> <LI> New crosslinker assists the crosslinked network in coatings at lower temperature. </LI> <LI> New crosslinker can be usefully applied in low-temperature curing technologies. </LI> </UL> </P>

Synthesis of Wood Adhesive Derived from the Milk Protein and the Blocked Isocyanate

Yuna Ha,Sang-Min Lee,Hyang-Yeol Lee 한국유화학회 2013 한국응용과학기술학회지 Vol.30 No.3

To investigate the adhesion effect of sodium bisulfite content in making blocked isocyanate, wood adhesive PB-1, PB-2, PB-3 and PB-4 containing sodium bisulfite content of 15%, 22.5%, 30% and 37.5% were synthesized respectively. As a result, when the amount of sodium bisulfite increased in adhesives, the tensile strength was found to be proportionally increased. The final adhesive mixtures were manufactured using a two-components system which are prepared by mixing two separate protein and BI solutions due to the precipitate in the adhesives. As PVA was added to adhesives to increase tenacity, the plywood dehiscence phenomenon after cold pressing process was declined. By addition of PVA, the tensile strength was improved up to 6.5~7kgf/cm2 with BI/protein ratio from 1:6 up to 1:8. Phase separation between milk fat and aqueous layer was disappeared after addition of emulsifier, Tween 20. Additon of Tween 20 showed tensile strength up to 5 ~ 6.5 kgf/cm2 at NCO/protein ratio of 1:12 ~ 1:14 without phase separation.