Predicting the water-sensitivity of film-forming coatings additives by water vapor sorption : with application to thickeners and rheology modifiers / Greg D. Shay in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 68, N° 854 (03/1996)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 68, N° 854 (03/1996) . - p. 51-63 Titre : Predicting the water-sensitivity of film-forming coatings additives by water vapor sorption : with application to thickeners and rheology modifiers Type de document : texte imprimé Auteurs : Greg D. Shay, Auteur ; Keith R. Olesen, Auteur ; Jeanne L. Stallings, Auteur Année de publication : 1996 Article en page(s) : p. 51-63 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Couches minces Epaississants Humidité -- Absorption Mesure Revêtements Revêtements -- Additifs Vapeur d'eau Index. décimale : 667.9 Revêtements et enduits Résumé : Although present in relatively low concentrations, additives such as thickeners, rheology modifiers, dispersants, and surfactants can contribute to the water sensitivity of coatings due to their inherent affinity for moisture. Because of the number of additives often present and the variable response possible within different formulations, a method was sought to examine the moisture affinity of individual additives in the absence of other coating components. A simple gravimetric procedure with high sensitivity and good repeatability was developed based on water vapor sorption (WVS). In this paper, the technique is applied to a variety of commercial thickeners and rheology modifiers commonly employed in waterborne coatings. Although alkali-swellable emulsions of the conventional (ASE) and associative (HASE) varieties are generally considered to be more water sensitive than nonionic thickener types, these carboxyl functional polymers in their acid form actually showed much lower moisture affinities. WVS for the anionic ASE and HASE thickeners was a function of polymer composition, type of counter ion, base volatility, dry time, and the state of neutralization prior to conducting the test. Note de contenu : - CONCEPTS/THEORY : Causes of water-sensivity - Moisture affinity methods - Water vapor sorption theory - EXPERIMENTAL DETAILS : Test method - Materials - RESULTS AND DISCUSSION : General observations - Test repeatablity - Effect of film weight - Effect of temperature - Comparative WVS thickener evaluations - Effect of neutralizing agents with ASE/HASE - Degree of neutralization with ASE/HASE - Estimation of diffusion and partition coefficients - Molecular weight - Other film properties Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18467 [article]

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
003524	-	Périodique	Bibliothèque principale	Documentaires	Exclu du prêt

Quantitative method for determination of thickener equilibration in coatings / Greg D. Shay in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 71, N° 890 (03/1999)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 71, N° 890 (03/1999) . - p. 51-59 Titre : Quantitative method for determination of thickener equilibration in coatings Type de document : texte imprimé Auteurs : Greg D. Shay, Auteur ; Keith R. Olesen, Auteur ; David L. Hardman, Auteur Année de publication : 1999 Article en page(s) : p. 51-59 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Epaississants Formulation (Génie chimique) Mélanges (chimie) Revêtements en phase aqueuse -- Additifs:Peinture en phase aqueuse -- Additifs Rhéologie Viscosimétrie Index. décimale : 667.9 Revêtements et enduits Résumé : A quantitative method for the determination of thickener incorporation rates and thickener equilibration times (TET) in coatings has been developed using a digital Krebs viscometer. Upon adding thickener to a coating sample, the viscometer simultaneously provides viscosity readout and continuous mixing at constant speed with degree of agitation simulating the relatively poor mixing conditions observed in some paint production equipment near the end of the process cycle. By plotting viscosity as a function of mixing time on the instrument, rates of incorporation and equilibration were obtained. The method proved to be reliable and generally reproducible in limited testing with apparent applicability to a variety of thickener types in both aqueous solution and in actual latex coating formulations. Meaningful comparisons of incorporation are now possible to facilitate appropriate thickener selection and to provide insight regarding optimal modes of incorporation or orders of addition for process cycle time reduction. Note de contenu : - INTRODUCTION : Thickener types and incorporation options - Thickener equilibration - EXPERIMENTAL : Detailed procedure for aqueous solutions - Detailed processus for pigmented coatings - RESULTS AND DISCUSSION : Effect of thickener concentration in paint - Effect of temperature - Procedure repeatability in aqueous solution - Effect of thickener addition rate - Effect of thickener type in aqueous solution - Instrument and viscosity stability in aqueous solution - Effect of thickener type in pigmented coatings - Effect of thickener dilution in paint - Effect of base addition order in a HASE thickener Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18029 [article]

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
009604	-	Périodique	Bibliothèque principale	Documentaires	Exclu du prêt

Tailoring HASE rheology through polymer design : Effects of hydrophobe size, acid content, and molecular weight / Wenjun Wu in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 2, N° 6 (04/2005)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 2, N° 6 (04/2005) . - p. 423-433 Titre : Tailoring HASE rheology through polymer design : Effects of hydrophobe size, acid content, and molecular weight Type de document : texte imprimé Auteurs : Wenjun Wu, Auteur ; Greg D. Shay, Auteur Année de publication : 2005 Article en page(s) : p. 423-433 Note générale : Bibliogr. Langues : Américain (ame) Tags : Polymère  associatif  Viscosité  cisaillement  nul  Matériau  revêtement  Modélisation  Propriété  rhéologique  Etude  expérimentale  Dispersion  aqueuse  Peinture  Application  Solution  Relation  masse  moléculaire  propriété  Ecoulement  cisaillé  Modèle  composition  Latex  Epaississant  Polyélectrolyte  Terpolymère  Groupe  hydrophobe  latéral  Méthacrylique  acide  copolymère  Acrylate  d'éthyle Index. décimale : 667.9 Revêtements et enduits Résumé : Hydrophobically modified alkali-soluble emulsion (HASE) polymers are an important class of rheology modifiers for waterborne coatings applications. They are typically prepared as terpolymers by emulsion polymerization of ethyl acrylate (EA), methacrylic acid (MAA), and an associative macromonomer. The viscosity development and shear responses of HASE solutions depend on a number of factors. This article presents rheological data reflecting the impacts of three key variables: hydrophobe size, acid content, and molecular weight, on model HASE thickening and rheological performance. The relative contributions of hydrophobic association, chain expansion, and polymer chain length are discussed. In steady shear flow, all thickener solutions approached some constant low-shear viscosity at small deformation rates. At the same molar composition, larger hydrophobe size resulted in higher viscosity development and greater shear thinning behavior. The amount of acid monomer in HASE polymers can influence the balance between hydrophobic attraction and electrostatic repulsion forces. It was found that a minimum of 15 wt% MAA was required to effect dissolution and thickening of the model HASE polymers. Increasing the MAA level yielded higher zero-shear viscosity and storage modulus G' with maximal values being obtained at 40% MAA. The molecular weight of the model thickeners was controlled by the amount of chain transfer agent (CTA) added during polymerization. When the CTA level was below 0.1 wt% based on total monomers, the polymer solutions displayed shear-thinning behavior. A small increase in CTA concentration beyond 0.1% resulted in a dramatic change to Newtonian flow, and the solution viscosity was nearly two orders of magnitude lower. The model thickeners were also tested in a vinyl acrylic architectural paint formulation. The effects of each individual factor on paint thickener efficiency, high-shear, and low-shear properties are discussed and compared with solution rheology for predictive relationships. DOI : 10.1007/BF02733885 En ligne : https://link.springer.com/content/pdf/10.1007%2FBF02733885.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3837 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
001483	-	Périodique	Bibliothèque principale	Documentaires	Disponible

The effects of neutralizing bases on the water sensitivity of HEURASE rheology modifiers and their performance in low VOC paints / Greg D. Shay in SURFACE COATINGS INTERNATIONAL, Vol. 80, N° 6 (06/1997)

[article]  inSURFACE COATINGS INTERNATIONAL > Vol. 80, N° 6 (06/1997) . - p. 285-293 Titre : The effects of neutralizing bases on the water sensitivity of HEURASE rheology modifiers and their performance in low VOC paints Type de document : texte imprimé Auteurs : Greg D. Shay, Auteur ; J. L. Stallings, Auteur ; P. J.-M. Manus, Auteur Année de publication : 1997 Article en page(s) : p. 285-293 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Peinture  eau'  Adjuvant  Epaississant  'Propriété  rhéologique'  'Composé  hydrophobe'  Uréthane  Ethoxylate  Sorption  'Vapeur  d'eau'  Neutralisation  'Base  chimique' Index. décimale : 667.9 Revêtements et enduits Résumé : Thickeners and rheology modifiers (TRMs collectivity) are necessary ingredients in nearly all architectural and industrial water-borne coatings formulations. The majority of these coatings additives are organic polymers of either the associative or the non-associative variety depending on the primary mode of thickening. As such, they are film-formers to varying degrees and technically could be considered part of the binder system in a coating. When they are viewed in this capacity, they comprise a minor though important fraction of the total binder in a typical paint formulation. Based on a recent survey of some 250 architectural interior and exterior coating formulas obtained from supplier literature, the average concentration of TRMs on an active weight basis was approximately 2,5% on latex binder solids. Though the amount is relatively small, most of these TRMs are inherently water soluble and considerably lower in molecular weight than the most latex binders, and because of this, these TRMs tend to impart some degree of water sensitivity to the coating formulations in which they are incorporated. Among the properties that may be affected are scrub resistance, wet adhesion, blister resistance and corrosion resistance. Note de contenu : - HEURASE TRMs - Determining the moisture affinity of additives by water vapour sorption - Hydrophilicity for HEURASE relative to other TRMs - Effect of ionization and base volatility on WVS of HEURASE films - Effect of base type on WVS - WVS on paints containing HEURASE with different neutralizing bases - HEURASE neutralizing bases in a low VOC coating formulation - HEURASE neutralizing agents in low VOC paints - HEURASE relative to commercial and cellulosic thickened paints Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17191 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
006583	-	Périodique	Bibliothèque principale	Documentaires	Disponible

---

1 (1 - 4 / 4)