2K waterborne clearcoat—a competition between crosslinking and side reactions

Collong, W.; Göbel, A.; Kleuser, B; Lenhard, W; Sonntag, MH Michael

doi:10.1016/s0300-9440(02)00052-8

Cited by 27 publications

(13 citation statements)

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“…It can be seen that pH is decreasing to the 67 % conversion, followed by a constant value afterwards. As reported 17,18 , the pH drop is attributed to the formation of carbon acid from CO 2 which is a side product of the NCO reaction with water. 3,5,7,[15][16][17][18] A pH of (7.00 ± 0.05) seems to be the equilibrium value in this system and is close to the reported value of 6.9.…”

Section: Molecular Massmentioning

confidence: 54%

“…As reported 17,18 , the pH drop is attributed to the formation of carbon acid from CO 2 which is a side product of the NCO reaction with water. 3,5,7,[15][16][17][18] A pH of (7.00 ± 0.05) seems to be the equilibrium value in this system and is close to the reported value of 6.9. 17 Due to the fact that new ions are formed, it is quite clear that the conductivity increase is practically a mirror image of the pH curve.…”

Section: Molecular Massmentioning

confidence: 54%

“…5,12,16 Due to the system complexity, where many principles are in place but only a few have an important influence on the final macroscopic material properties, this field of research is rather more of an industrial importance. 17,18 In recent studies, the main focus was put on hardening two-component aqueous polyurethane coatings where the reactions and the mechanism itself are similar to those of a bulk PUD. However, the conditions (e.g., the water content) for coating hardening are significantly different.…”

Section: 2mentioning

confidence: 99%

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Monitoring of polyurethane dispersions after the synthesis

Ocepek¹,

Zabret²,

Kecelj³

2015

Mater. Tehnol.

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Chemical and physical parameters of the aqueous polyurethane dispersion (PUD) were studied after the synthesis. A prepolymer mixing process with a limited-chain extension step was used in order to examine the polymer and dispersion behavior with respect to the ageing time. Measurements of free isocyanate groups were performed with the aid of Fourier transform infrared spectroscopy (FT-IR). The pseudo-first-order kinetics of NCO disappearance was proposed and the value of the corresponding constant was determined. Additionally, particle size, particle size distribution, pH, conductivity and molecular mass were monitored and compared. Keywords: polyurethane dispersion, colloid, FT-IR V raziskavi smo preu~evali spreminjanje kemijskih in fizikalnih parametrov vodne poliuretanske disperzije (PUD) po sintezi. Disperzijo smo sintetizirali po postopku vme{avanja prepolimera z omejenim podalj{evanjem verig za preu~evanje polimerne disperzije z ozirom na~as po sintezi. Merjenje prostih izocianatnih skupin smo izvedli z metodo Fourierjeve transformacijske infrarde~e spektroskopije (FT-IR). Predpostavili smo kineti~ni model psevdoprvega reda z ozirom na reakcije izocianatnih skupin ter dolo~ili vrednost kineti~ne konstante. Dodatno smo spremljali in primerjali povpre~ne velikosti delcev, porazdelitev velikosti delcev, pH, prevodnost in molekulsko maso.

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Section: Molecular Massmentioning

confidence: 54%

Section: Molecular Massmentioning

confidence: 54%

Section: 2mentioning

confidence: 99%

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Monitoring of polyurethane dispersions after the synthesis

Ocepek¹,

Zabret²,

Kecelj³

2015

Mater. Tehnol.

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“…Those side reactions bind reaction partners for the original reactions. This lead to an unfavorable share of hardener to resin components and therefore in a slower curing [31] due to a reduced number of reaction starting points, which finally increases the gel time.…”

Section: Influence Of Autoclave Vacuummentioning

confidence: 99%

A qualitative, process-parameter-based model for the release agent transfer during CFRP-part production: an approach to increase the initial bondability

2017

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“…Firstly, isocyanate reacts with alcohols to form urethane linkages (R1), with amines to form urea groups (R2), and with water to form carbamic acid, which is subsequently converted to amines and carbon dioxide (R3) [13,14].…”

Section: Introductionmentioning

confidence: 99%