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Further development of low-viscosity polyester polyols for high-solids 2K polyurethane coatings in COATINGS WORLD, Vol. 24, N° 3 (03/2019)  

[article]  inCOATINGS WORLD > Vol. 24, N° 3 (03/2019) Titre : Further development of low-viscosity polyester polyols for high-solids 2K polyurethane coatings Type de document : texte imprimé Année de publication : 2019 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Absorbeurs de rayonnement ultraviolet Adhésion Décoloration Dureté (matériaux) Epoxydes Formulation (Génie chimique) Haut extrait sec Polyaspartiques Polyesters Polyols Polyuréthanes Résistance au rayonnement ultraviolet Résistance aux conditions climatiques Résistance chimique Revêtements -- Propriétés mécaniques:Peinture -- Propriétés mécaniques Revêtements bi-composant:Peinture bi-composant Test d'immersion Index. décimale : 667.9 Revêtements et enduits Résumé : Formulators are required to comply with increasingly stringent VOC regulations and, at the same time, maintain the performance characteristics expected from the coating system. Traditionally, there have been three ways to reduce VOCs in coatings: by moving toward waterborne formulations, making higher solids coatings, or using “exempt” solvents. Waterborne technology greatly reduces the VOC content, but commonly lags behind the performance of solventborne coatings, while high solid systems are typically less economical per gallon. Systems containing exempt solvents can only be used from a regulatory point of view in specific areas of the globe. In order to overcome these challenges, we developed a new set of polyester polyols with low room temperature viscosities that reduce VOC content in coating formulations and provide excellent coating characteristics. This work demonstrates the use of these polyols in 2K polyurethane solventborne low VOC systems and describes their performance characteristics in preventative maintenance and floor coatings. This paper includes discussion of the adhesion to various metals and plastics, extended weatherability performance and starting point formulations. Note de contenu : - Picture 1 : Chemical immersion resistance test of a composite formulation sample. - Fig. 1 : Calculated VOC levels for standard developmental resin coating formulations - Fig. 2 : Shore D coating hardness for standard and developmental resin coating formulations - Fig. 3 : Pencil hardness for standard and developmental resin coating formulations - Fig. 4 : Abrasion resistance for standard and developmental resin coating formulations - Fig. 5 : Total weight change of the standard and developmental resin coating formulation composites after four weeks immersion in various chemicals - Fig. 6 : QUV-A gloss stability of coating formulations without UV absorbers - Fig. 7 : QUV-A gloss stability of coating formulations with UV absorbers - Fig. 8 : QUV-A color change, δE of coating formulations without UV absorbers - Fig. 9 : QUV-A color change, δE of coating formulations with UV absorbers - Table 1 : Commercial resin standards - Table 2 : Developmental high-functional, low-viscosity polyols - Table 3 : 2K polyurethane formulations - Table 4 : 2K aspartic resin formulations - Table 5 : 2K epoxy resin formulations - Table 6 : ASTM standards used - Table 7 : Cross Hatch adhesion summary - Table 8 : Polyurethane coating mechanical properties - Table 9 : Coating formulations weathering studies - Table 10 : Developmental resin compatibility En ligne : https://www.coatingsworld.com/issues/2019-03-01/view_technical-papers/further-de [...] Format de la ressource électronique : Html Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32508 [article]

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Fumed metal oxide dispersions expand aqueous inkjet printing substrates / Tianqi Liu in COATINGS WORLD, Vol. 24, N° 3 (03/2019)  

[article]  inCOATINGS WORLD > Vol. 24, N° 3 (03/2019) Titre : Fumed metal oxide dispersions expand aqueous inkjet printing substrates Type de document : texte imprimé Auteurs : Tianqi Liu, Auteur ; Koen Burger, Auteur Année de publication : 2019 Langues : Américain (ame) Catégories : Alcool polyvinylique Alumine Couche de base Dispersions et suspensions Encre en phase aqueuse Floculation Impression jet d'encre Liants Matières plastiques -- Revêtement Oxydes métalliques Polyéthylène téréphtalate Polyuréthanes Potentiel zeta Revêtements organiques Silice La silice est la forme naturelle du dioxyde de silicium (SiO2) qui entre dans la composition de nombreux minéraux. La silice existe à l'état libre sous différentes formes cristallines ou amorphes et à l'état combiné dans les silicates, les groupes SiO2 étant alors liés à d'autres atomes (Al : Aluminium, Fe : Fer, Mg : Magnésium, Ca : Calcium, Na : Sodium, K : Potassium...). Les silicates sont les constituants principaux du manteau et de l'écorce terrestre. La silice libre est également très abondante dans la nature, sous forme de quartz, de calcédoine et de terre de diatomée. La silice représente 60,6 % de la masse de la croûte terrestre continentale. Index. décimale : 667.9 Revêtements et enduits Résumé : As aqueous inkjet continues to take market shares from traditional printing techniques, it must expand its substrates from traditional office paper to a broader spectrum of substrates used for packaging, signage and labels. CAB-O-SPERSE® silica and alumina dispersions can help prime difficult substrates to work with aqueous inkjet inks because of the porosity they generate and their surface charge characteristics. These dispersions enable the formulation of precoats that can greatly enhance optimized image quality such as high color saturation, less mottle and wet smudge resistance. They also offer stability and flexibility in the waterborne coating systems. Note de contenu : - Fumed metal oxide dispersions - key component in an aqueous inkjet receptive coating - Dispersions offer stability and flexibility in waterborne coatings - Fig. 1 : Examples of aqueous inkjet printing issues due to slow liquid removal from the printing surface - Fig. 2 : Pore volume distribution in coatings made with fumed metal oxide dispersions - Fig. 3 : Kyocera test bed printing at 250 feet/min of an aqueous inkjet ink sets on PET substrates. A: original PET film ; B : PET film precoated with PG003 dispersion and a polyurethane binder ; C : timed finger smear test on cyan color printed on the precoated PET - Fig. 4 : Kyocera test bed printing at 250 feet/min of an aqueous inkjet ink set on a porous substrate. Three secondary colors (blue, red and green) and one composite black (cyan, magenta and yellow) are printed. A : original paper liner for corrugated board ; B : paper liner precoated with PG003 dispersion and a polyurethane binder - Fig. 5 : Schematic illustration of an inkjet receptive coating made using a silica dispersion and a polymer binder - Fig. 6 : Zeta potential curves for two representative silica dispersions - Fig. 7 : Stability of a fumed silica dispersion (2020K) on the left vs a surface modified calcium carbonate dispersion (on the right) in the presence of a polyvinyl alcohol binder after overnight - Fig. 8 : Photos of an image under films coated on PET. A : coating made using dispersion 4012K ; B : coating made using dispersion 1030K - Fig. 9 : Flocculation in a cationic coating system with low charge density cationic silica and a cationic polymer latex - Fig. 10 : Coating solution stability at t=1hr and t= 1 month when cationic silicas are mixed with a cationic charged polyurethane binder. Vial on the left : low charge density cationic silica; vial on the right : higher charge density cationic silica En ligne : https://www.coatingsworld.com/issues/2019-03-01/view_technical-papers/fumed-meta [...] Format de la ressource électronique : Html Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32509 [article]

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Coatings world Vol. 24, N° 3 URL