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Novel concept for low temperature curing powder coatings based on hyperbranched polyesters / Mats Johansson in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 906 (07/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 906 (07/2000) . - p. 49-54 Titre : Novel concept for low temperature curing powder coatings based on hyperbranched polyesters Type de document : texte imprimé Auteurs : Mats Johansson, Auteur ; Eva Malmström, Auteur ; Andreas Jansson, Auteur ; Anders Hult, Auteur Année de publication : 2000 Article en page(s) : p. 49-54 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Basses températures Copolymères greffés Peinture poudre -- Séchage sous rayonnement ultraviolet Polyesters Polymères aliphatiques Polymères cristallins Polymères ramifiés Réticulation (polymérisation) Revêtements poudre:Peinture poudre Index. décimale : 667.9 Revêtements et enduits Résumé : The concept of using hyperbranched polymers as scaffolds for solid thermoset resin applications is described. A series of semi-crystalline methacrylate-functional aliphatic polyesters has been synthesized and characterized for applications as solid thermoset resin, e.g., powder coating resins. The polyester resins have been crosslinked by UV irradiation producing either amorphous or semi-crystalline crosslinked films depending on the initial structure. The resins are based on hyperbranched aliphatic polyesters onto which crystalline linear aliphatic polyester chains have been grafted and end-capped with methacrylate moieties. The resins exhibit a rheological behavior suitable for low temperature curing powder coatings, i.e., films that can be readily formed and UV cured at temperatures below 80°C. Note de contenu : - SYNTHESIS : General procedure for grafting of poly(epsilon-caprolactone) (epsilon-PCL) polyesters 1 and 2 exemplified by synthesis of P2G-epsilonPCL(DP=10),3 - General procedure for methacrylation of the hydroxy-functional polymers 3-6 exemplified by the synthesis P2G-epsilonPCL(DP=10)-MA - UV curing (crosslinking) of polyesters 7-10: - CHARACTERIZATION TECHNIQUES : Rheology - Thermal characterization - Residual unsaturation - Microscopy - Photo DSC - Dynamic mechanical properties - SYNTHESIS : Graphting of epsilon-caprolactone onto the hyperbranched polyesters - Methacrylate functionalization - Rheological and physical properties of polyesters 7-10 before crosslinking - Curing performance of resins 7-10 - Mechanical propertier of UV-cured films of resins 7-10 Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17985 [article]

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Effect of acid groups in hydroxyl functional resins on the properties of polyester-urethane powder coating / Bin Wu in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 906 (07/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 906 (07/2000) . - p. 55-62 Titre : Effect of acid groups in hydroxyl functional resins on the properties of polyester-urethane powder coating Type de document : texte imprimé Auteurs : Bin Wu, Auteur ; Sanjay Padaki, Auteur Année de publication : 2000 Article en page(s) : p. 55-62 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acidité Couches minces Essais de brouillard salin Formulation (Génie chimique) Groupement carboxyle Hydroxyle En chimie organique, un hydroxyle (ou oxhydryle) peut désigner deux entités. Un groupement -OH, appelé aussi hydroxy, qui se rencontre en particulier dans les alcools et les phénols. Un radical : HO^{\bullet}. Il est produit par exemple lors de réactions de dissociation de peroxydes, en présence d'ions de métaux de transition (Fe(II), Cu(I), réaction de Fenton), de chauffage ou de rayonnement. Liants Polyesters Polyuréthanes Résistance aux conditions climatiques Réticulation (polymérisation) Revêtements -- Propriétés mécaniques:Peinture -- Propriétés mécaniques Revêtements poudre:Peinture poudre Index. décimale : 667.9 Revêtements et enduits Résumé : Hydroxyl-terminated polyester resins with different acid numbers were synthesized and used in powder coating formulations. Coatings were formulated with isophorone diisocyanate (IPDI)-based hardeners and tested for mechanical performance, appearance, and weathering. This study found that resins containing a high concentration of residual acid groups (also referred to as undercondensed resins) had to be formulated according to their total reactive number, the sum of acid and hydroxyl numbers, in order to achieve complete cure. High acid numbers also caused poor overbake and salt spray resistance. The addition of adipic or benzoic acids to the powder formulation accelerated cure. Note de contenu : - RESULTS AND DISCUSSION: Resins - Powder formulation - Curing chemistry - Effect of AN and crosslinker stoichiometry on curing - Acid catalysis - Effect of residual acid groups on coating properties - Overbake resistance - Salt fog testing (ASTM B 117) - Curing residual carboxyl groups Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17986 [article]

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Drying of alkyd emulsion paints / P. K. Weissenborn in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 906 (07/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 906 (07/2000) . - p. 65-74 Titre : Drying of alkyd emulsion paints Type de document : texte imprimé Auteurs : P. K. Weissenborn, Auteur ; A. Motiejauskaite, Auteur Année de publication : 2000 Article en page(s) : p. 65-74 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Agents dispersants (chimie) Cobalt Dioxyde de titane Pigments inorganiques Polyalkydes Revêtements -- Additifs Revêtements en phase aqueuse:Peinture en phase aqueuse Siccatifs Un siccatif est une substance qui joue un rôle de catalyseur en accélérant le séchage ou durcissement (polymérisation) d'un matériau tel une huile ou une peinture à base d'huile (pour le bâtiment ou les artistes). Tags : 'Matériau  revêtement'  'Peinture  eau'  émulsion'  'Alkyde  résine'  'Formation  film'  Séchage  Siccatif  'Cobalt  Composé'  'Pigment  minéral'  'Titane  Oxyde'  Adjuvant  Dispersant  'Etude  expérimentale' Index. décimale : 667.9 Revêtements et enduits Résumé : The drying and film formation of long oil alkyd emulsions was investigated with emphasis on loss of dry upon storage. The main reason for loss of dry was adsorption of the cobalt (drier) on pigment surfaces as a precipitated hydroxide. Titanium dioxides with alumina surface treatment and organic pigments were most detrimental to drying. Acrylate- and phosphate-based dispersants also deactivated the cobalt, presumably due to complexation and precipitation of the cobalt. Emulsions prepared with an emulsifiable cobalt drier containing 2,2'-bipyridyl (complexing agent for cobalt) showed the best resistance to loss of dry. Atomic force microscopy of films formed from the emulsions showed that the emulsifier migrated to the film surface which, when washed with water, leaves holes or pits in the film. The pits were arranged in a hexagonal pattern characteristic of Bénard cells, which form due to surface tension and/or temperature gradients generated in the film during evaporation of water. Note de contenu : - MATERIALS: Alkyd resins - Emulsifiers - Driers - Dispersants - Pigments - Other Reagents - METHODS: Alkyd resin emulsification - Addition of dispersants to LO83 alkyd emulsions - Addition of pigments to LO83 Alkyd emulsions - Storage stability and loss of dry tests - BK drying tests - Emulsion characterization - Film formation studies - DRYING PROPERTIES OF PURE ALKYD EMULSIONS: Effect of emulsion pH - Effect of cobalt form and location - Other variables - DRYING PROPERTIES OF EMULSIONS CONTAINING PIGMENT DISPERSANTS - DRYING PROPERTIES OF EMULSIONS CONTAINING PIGMENTS - FILM FORMATION Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17987 [article]

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Weather-stable low-gloss powder coatings / P. Thometzek in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 906 (07/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 906 (07/2000) . - p. 75-79 Titre : Weather-stable low-gloss powder coatings Type de document : texte imprimé Auteurs : P. Thometzek, Auteur ; U. Freudenberg, Auteur ; U. Meier-Westhues, Auteur ; Ken Yonek, Auteur Année de publication : 2000 Article en page(s) : p. 75-79 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Alliages polymères Brillance (optique) Couches minces Formulation (Génie chimique) Polyesters Polyuréthanes Résistance aux conditions climatiques Réticulants Réticulation (polymérisation) Revêtements poudre:Peinture poudre Rugosité Index. décimale : 667.9 Revêtements et enduits Résumé : Manufacturing weather-stable powder coatings with a matte surface and consistent quality is a challenge to the powder coatings industry. Technically acceptable results are achieved using the dry blend process, but one-shot formulations based on polyurethane raw materials or the use of a bifunctional polyurethane matte hardener offer interesting alternative solutions. Investigation of the powder coating films using a perthometer and an electron microscope provides a deeper understanding of the matte powder coating systems. Note de contenu : - METHODS OF MATTING POWDER COATINGS : Matting additives - Dry blend process - One-shot matte formulations - Powder coating raw materials with different functional groups - EXPERIMENTAL : Materials - Processing - Application, curing, and testing - DISCUSSION : Dry blend process with polyesters of different hydroxyl numbers - Influence of OH 300 polyester on coating properties - Investigations of the surface structure during baking - One-shot matte formulations - Crosslinkers with two different functional groups - Applications for the matte hardener - Correlation between surface roughness and gloss Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18022 [article]

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Effect of turnover rate on the change of concentration of an unstable compound in a dip coating bath / Tatsuo Sato in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 906 (07/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 906 (07/2000) . - p. 81-83 Titre : Effect of turnover rate on the change of concentration of an unstable compound in a dip coating bath Type de document : texte imprimé Auteurs : Tatsuo Sato, Auteur Année de publication : 2000 Article en page(s) : p. 81-83 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Dip-coating Tags : Peinturage  'Au  trempé'  'Composition  chimique'  Modification  'Composé  instable' Index. décimale : 667.9 Revêtements et enduits Résumé : The effect of turnover rate on the change of concentration of unstable (degradable) compounds in a dip coating bath during a continuous coating process was theoretically calculated as a function of the degradation rate of the compound. It is assumed that the bath is replenished by the same coating material as that in the original bath to maintain the volume of the material in the bath constant. The results show that the fraction of the unstable compound in the bath at the end of the nth day is given by formula math where t is the number of days for one turnover and formula math where P is the fraction of the compound remaining undegraded in the bath per day. The equilibrium fraction of the compound after infinite coating days is given by formula math The concentration of the compound in the replenishing material (Cr) to maintain the original concentration in the bath (Co) constant is given by formula math. Note de contenu : - COMPUTATION : Change of the concentration of unstable compounds in a dip coating bath with time - Equilibrium concentration of the compound - Concentration of the compound - Concentration of the compound in replenishing coating material to maintain the concentration in the bath constant - RESULTS AND DISCUSSION Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18023 [article]

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