The behavior of MEKO-blocked isocyanate compounds in aluminum flake pigmented, polyester–polyurethane can coating systems

Jiang, Chao; Driffield, Malcolm; Bradley, Emma; Castle, Laurence; Oldring, P. K. T.; Guthrie, James T.

doi:10.1007/s11998-009-9174-4

Cited by 8 publications

(8 citation statements)

References 5 publications

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“…This observation confirms that isocyanate groups were completely reacted with aromatic secondary amines. Similar to FTIR spectra 1 H and 13 C-NMR spectra also show identical peaks for all blocked isocyanates (1)(2)(3)(4)(5). A typical example of proton and carbon NMR is given in Figures 3 and 4, respectively.…”

supporting

confidence: 61%

“…2-5 mg of blocked isocyanates (1)(2)(3)(4)(5) were sealed in hermetic aluminum pans and the experiments were carried out from ambient temperature to 350 C at a heating rate of 10 C/min under nitrogen atmosphere.…”

Section: Methodsmentioning

confidence: 99%

“…Fourier Transfer Infrared (FTIR) spectra for the blocked isocyanates (1)(2)(3)(4)(5) were recorded on a Bruker Tensor 27 spectrometer (Bruker Optik GMbH, Ettlingen, Germany) by KBr pellet method. Thirty-two scans at a resolution of 4 cm ¡1 were set to produce a FTIR spectrum.…”

Section: Methodsmentioning

confidence: 99%

“…The blocked isocyanate systems is used in many applications, including coatings (3)(4)(5)(6), adhesives (7)(8)(9), sealants (10,11), and elastomers (12,13). Traditional heat-curable blocked isocyanate systems had deblocking temperatures of 160 C or higher (1,2).…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and Deblocking Studies of Low Temperature Heat-Curable Blocked Polymeric Methylene Diphenyl Diisocyanates

Sankar

Yan

2014

Journal of Macromolecular Science, Part A

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One package heat curable polyurethane system typically requires blocked isocyanates with a relatively low deblocking temperature. In this study, a series of new aromatic secondary amines blocked polymeric methylene diphenyl diisocyanate (pMDI) was synthesized and characterized. Hot-stage FTIR, DSC and TGA spectroscopic methods were used to determine the deblocking temperatures of the blocked isocyanates. Cure reaction between the blocked isocyanates and a commercial polyl (PPG-2000) were carried out to establish structure and property relationship. Deblocking temperature and gel time of the blocked isocyanates based on N-methylaniline and N-methyl-o-toludine were lower than the blocked isocyanates with imidazole and methyl 4-methylaminobenzoate. Unexpected high deblocking temperature of imidazole and methyl 4-methylaminobenzoate was due to intra molecular hydrogen bonding. Solubility behavior of the blocked isocyanates was also studied using a series of polyols (PEG-400, Terathane-2000, PPG-2000, and castor oil).

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supporting

confidence: 61%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis and Deblocking Studies of Low Temperature Heat-Curable Blocked Polymeric Methylene Diphenyl Diisocyanates

Sankar

Yan

2014

Journal of Macromolecular Science, Part A

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“…[1][2][3] In order to meet the demand of various applications, the types of diisocyanates play a very important role during the synthesis of polyurethanes. As is known, most established diisocyanates based on isophorone diisocyanate (IPDI) or toluene diisocyanate (TDI) lead to high toxicity and carcinogenicity, as well as rather high activity due to their free isocyanate groups, which readily react with the functional groups.…”

Section: Introductionmentioning

confidence: 99%

Kinetic and Thermodynamic Studies of the Urethane Reaction Based on 1,3-diazetidine-2,4-dione and 4-(Tetrahydro-Pyran-2-yloxy)-butan-1-ol

Gong

Yang

Tao

et al. 2014

International Journal of Polymer Analysis and Characterization

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The urethane reaction of symmetrical diisocyanate 1,3-diazetidine-2,4-dione (uretdione) with 4-(tetrahydro-pyran-2-yloxy)-butan-1-ol (mono-THP ether) was carried out in chlorobenzene with 1,4-diazabicyclo [2.2.2] octane (DABCO) or dibutyltin dilaurate ( DBTDL) as catalyst. Analysis of the second-order rate constants of those systems indicated that k followed the order of DABCO > DBTDL. Then the kinetics of the urethane reaction was studied by means of in situ FT-IR. Due to a greater distance apart of the two isocyanate groups in the molecule, there was no significant reactivity difference between them. Finally, activation energy, activation enthalpy, and activation entropy for the catalyzed reaction were also determined, followed by a discussion of the reaction mechanism.

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Catalysis of Forward and Reverse Reactions of ϵ-Caprolactam-Blocked Polyisocyanate: Double Arrhenius Plots and Equilibrium Temperatures of a Thermally Reversible Reaction

Libni

Nasar

2017

ChemistrySelect

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ϵ‐Caprolactam blocked‐polyisocyanate is a commercially valuable raw material used mainly in the single‐package polyurethane coatings. In this study, kinetics of forward (blocking) and the reverse (deblocking) reactions of ϵ‐caprolactam‐blocked polyisocyanate catalysed by DABCO ‐ a tertiary amine, bismuth neodecanoate, calcium(II) 2‐ethylhexanoate – both non‐tin organometallics and a tin catalyst were studied using a hot stage FT‐IR spectrophotometer. It was found that calcium(II) 2‐ethylhexanoate showed highest catalytic activity in the forward reaction whereas this catalyst showed lowest activity in the reverse reaction. DABCO and bismuth neodecanoate showed same catalytic activity and that activity was high compared to that of tin(II) 2‐ethylhexanoate in the forward reaction whereas only DABCO showed high activity in the reverse reaction. As these reactions were carried out adapting neat condition, the rate constants obtained were used to construct the double Arrhenius plots for this thermally reversible reaction. All the double Arrhenius plots showed intersection, from the intersection point, equilibrium temperature and equilibrium rate constants of these reactions were determined. Compared to uncatalysed reaction, DABCO reduced the deblocking temperature 25 °C and shifted the equilibrium temperature 6 °C. The data such as time required for 60% conversion into product, deblocking temperature and equilibrium temperature reported in this paper are vital in the manufacturing and in the application of ϵ‐caprolactam‐blocked polyisocyanate.

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The behavior of MEKO-blocked isocyanate compounds in aluminum flake pigmented, polyester–polyurethane can coating systems

Cited by 8 publications

References 5 publications

Synthesis and Deblocking Studies of Low Temperature Heat-Curable Blocked Polymeric Methylene Diphenyl Diisocyanates

Synthesis and Deblocking Studies of Low Temperature Heat-Curable Blocked Polymeric Methylene Diphenyl Diisocyanates

Kinetic and Thermodynamic Studies of the Urethane Reaction Based on 1,3-diazetidine-2,4-dione and 4-(Tetrahydro-Pyran-2-yloxy)-butan-1-ol

Catalysis of Forward and Reverse Reactions of ϵ-Caprolactam-Blocked Polyisocyanate: Double Arrhenius Plots and Equilibrium Temperatures of a Thermally Reversible Reaction

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