[article]
| Titre : |
Development of low-temperature self-curable water soluble polyepoxide coatings for cathodic electrodeposition |
| Type de document : |
texte imprimé |
| Auteurs : |
Pramod Kumar, Auteur ; M. K. Trivedi, Auteur |
| Année de publication : |
2002 |
| Article en page(s) : |
p. 45-66 |
| Note générale : |
Biliogr. |
| Langues : |
Anglais (eng) |
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
Epoxidised phenol-novolac (EPN) type of polyepoxide resin was used for developing water-soluble cathodically electro-depositable coatings which could be self-curable without using any external/additional cross-linking agent. The self-curing of cathodically deposited films could be effected at a low temperature of 80°C in 30 min, as compared to 150-170°C in 30 min practised presently in many commercial cathodic electro-deposition (CED) installations. In this work, effect of varying molar ratio of secondary amines such as diethanol amine (DEtOA) and diethyl amine to epoxidised phenol-novolac (EPN) on the solubility of EPN-secondary amine adducts prepared at 80, 60 and 30°C for varying reaction times was investigated. Self-curing characteristics of EPN-DEtOA (1:2 moles) adduct at 30-160°C were studied. Kinetics of film growth during CED was investigated by using aqueous solutions of acetic acid neutralised EPN-DEtOA (1:2 moles) adduct. Variables for kinetic studies were deposition time (30-600 s), applied voltage (5-250 V) and solution concentration (1-20% (w/w)). By carrying out CED of polyepoxide films, values of electro-deposition (ED) characteristics found were: ED yield as 5.89 mg/cm2, Coulombic yield as 19.78 mg/C and dry film thickness (DFT) as 52.12 μm. Plots of DFT vs. deposition time (t), DFT vs, t1/2 and current density vs. field strength were drawn to calculate the values of Coulombic efficiency of the process and film conductivity. Cathodically electro-deposited films were finally characterised for physical properties, chemical resistance and corrosion protection performance. |
| Note de contenu : |
- Equipments - Reactor assembly - Electrodeposition cell
- EXPERIMENTAL PROCEDURES : modifications of EPN resin for cathodic electrodeposition - Determination of Tertiary Amine Value (TAV) of the prepared adduct - Infrared spectroscopy - Cathodic Electrodeposition of films - Determination of degree of cure - Physical examination of film properties - Chemical resistance of films - Protection by films against corrosion
- RESULTS AND DISCUSSION : Effect of molar ration of EPN to DEtOA on the characteristics of adduct - Effect of molar ration of EPN to DEA on the characteristics of adduct - Effect of reaction temperature and time on the characteristics of EPN-DEtOA (1:2 Moles) adducts - Curing characteristics of adduct films - Cathodic Electrodeposition of adduct films - Effect of deposition time on ED characteristics - Effect of applied voltage on ED characteristics - Effect of solution concentration - Effect of solution pH - kinetics of film growth during cathodic electrodeposition - Dry film thickness - Current density - Specific conductivity of the deposited film - Physical properties of films - Chemical resistance of films - Acid resistance - Methanol resistance - Corrosion resistance of films
- CONCLUSIONS : Based on the findings of this work, following conclusions can be drawn
- TECHNOLOGICAL CONTRIBUTION TO COATING INDUSTRY |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12364 |
in PAINTINDIA > Vol. LII, N° 6 (06/2002) . - p. 45-66
[article]
|
Aller sur edunet
Accueil
Development of low-temperature self-curable water soluble polyepoxide coatings for cathodic electrodeposition in PAINTINDIA, Vol. LII, N° 6 (06/2002)
