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Epoxy Nucleophile catalyzed transesterification / Gary P. Craun in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 67, N° 841 (02/1995)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 67, N° 841 (02/1995) . - p. 23-30 Titre : Epoxy Nucleophile catalyzed transesterification Type de document : texte imprimé Auteurs : Gary P. Craun, Auteur Année de publication : 1995 Article en page(s) : p. 23-30 Note générale : Blibliogr. Langues : Américain (ame) Catégories : Catalyseurs Cinétique chimique Copolymères Epoxydes Esterification Haut extrait sec Polyacryliques Polyesters Réactions chimiques Réticulation (polymérisation) Revêtements poudre:Peinture poudre Index. décimale : 667.9 Revêtements et enduits Résumé : Epoxy nucleophile catalyzed transesterification (ENCAT) is a new cure technology, which is particularly well-suited for coatings application. Acrylic and acrylic-polyester blends in high-solids paints self-cure with ENCAT under normal bake conditions to give an excellent balance of hardness, flexibility, and solvent resistance. Powder paints prepared with ester derivatives of epoxy resins self-cure, and likewise give an excellent balance of properties. The ENCAT catalyst is formed during cure by the combination of a nucleophile with an epoxide moiety. A strong base alkoxide, which is produced when the epoxide ring opens by nucleophilic attack, initiates transesterification. This mechanism is supported by 13C NMR and gas chromatographic studies. rate of transesterification is related to the structure of the hydroxyl and ester group undergoing transesterification. Transesterification rate is directly related to the concentrations of the nucleophile and epoxy co-catalysts, as well as to the basicity and nucleophilicity of the nucleophile Note de contenu : - EXPERIMENTAL : Model compound studies - Transesterification rate by gas chromatography - Polymer synthesis - Paint preparation and testing - RESULTS AND DISCUSSION : Model compound studies - TRANSESTERIFICATION RATE STUDIES : Evidence of transesterification by gas chromatography - Transesterification rate : nucleophile and epoxy co-catalyst effects - Transesterification rate : ester and hydroxyl structure effects - Paint properties Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18490 [article]

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Initiators for high-solids polyacrylates resins : selection guidelines and performance review / Ginger G. Myers in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 67, N° 841 (02/1995)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 67, N° 841 (02/1995) . - p. 31-37 Titre : Initiators for high-solids polyacrylates resins : selection guidelines and performance review Type de document : texte imprimé Auteurs : Ginger G. Myers, Auteur Année de publication : 1995 Article en page(s) : p. 31-37 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Amorceurs (chimie) Haut extrait sec Peroxydes Polyacrylates Polyaddition Index. décimale : 667.9 Revêtements et enduits Résumé : This paper covers the selection criteria for choosing an effective free-radical initiator for the polymerization of acrylic monomers. Two basic systems have been used to evaluate a large number of organic peroxides, including an original equipment manufacturer (OEM) model system. The systems and resin characterization procedures are described. Results of approximately 100 polymerizations using different initiators and conditions are presented. Table 6 summarizes all of the results obtained and can be used for initiator selection screening. Resin characterization, cost performance, and conversion are used as guidelines in all the initiator evaluations Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18502 [article]

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Novel organosilane crosslinking agents for powder coatings / S. F. Thames in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 67, N° 841 (02/1995)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 67, N° 841 (02/1995) . - p. 39-45 Titre : Novel organosilane crosslinking agents for powder coatings Type de document : texte imprimé Auteurs : S. F. Thames, Auteur ; K. G. Panjnani, Auteur ; S. D. Pace, Auteur ; Michael D. Blanton, Auteur ; B. R. Cumberland, Auteur Année de publication : 1995 Article en page(s) : p. 39-45 Note générale : Blibliogr. Langues : Américain (ame) Catégories : Epoxydes Organosilanes Polyesters Réticulants Revêtement poudre -- Additifs:Peinture poudre -- Additifs Index. décimale : 667.9 Revêtements et enduits Résumé : Organosilane dicarboxylic acids have been substituted for a portion of the carboxyl-terminated polyesters in conventional epoxy-polyester powder coatings and provide improvements in a number of performance characteristics. For instance, environmental scanning electron microscopy (ESEM) studies confirm improvements in flow and leveling ; the modified powders permit lower cure temperatures ; and chemical and weather resistance properties are improved as is their thermal stability. Adhesion and pencil hardness are essentially unchanged, but minor improvements are noted in some formulations. However, impact strength and flexibility are lowered for most silane-containing formulations, probably a consequence of higher aromatic content in the silane diacids Note de contenu : - Materials - Synthesis of monosubstituted organosilane dicarboxylic acids--Scheme 1 - Synthesis of monosubstituted organosilane dicarboxylic acids--Scheme 2 - Powder coating formulation - Testing equipment Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18503 [article]

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Styrenation of oils based on secondary esters of castors oil / O. S. Kabasakal in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 67, N° 841 (02/1995)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 67, N° 841 (02/1995) . - p. 47-51 Titre : Styrenation of oils based on secondary esters of castors oil Type de document : texte imprimé Auteurs : O. S. Kabasakal, Auteur ; F. Seniha Güner, Auteur ; A. Tuncer Erciyes, Auteur ; Yusuf Yagci, Auteur Année de publication : 1995 Article en page(s) : p. 47-51 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Esterification Huile de ricin et constituants Huiles et graisses végétales Liants Revêtements 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). Styrénation Index. décimale : 667.9 Revêtements et enduits Résumé : The synthesis of styrenated oils based on secondary esters of castor oil is described. The steps of the process are as follows : 1) esterification of castor oil with fatty acids of drying and semidrying oils ; 2) splitting of castor oil ester, and 3) conversion of the splitting mixture to either triglyceride or partial glyceride. While the triglyceride samples were styrenated by a conventional process, the partial glycerides' thermally labile azo groups were initially inserted into the oil molecule, and then this intermediate was reacted with styrene. The obtained styrenated oils showed good film properties Note de contenu : - Materials - Preparation of castor oil esters and their splitting - Preparation of tri and partial glycerides Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18504 [article]

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VOC testing comparison : EPA method 24 versus the cal poly method / V. C. Bud Jenkins in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 67, N° 841 (02/1995)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 67, N° 841 (02/1995) . - p. 53-59 Titre : VOC testing comparison : EPA method 24 versus the cal poly method Type de document : texte imprimé Auteurs : V. C. Bud Jenkins, Auteur ; Joseph C. Reilly, Auteur ; Bob Sypowicz, Auteur ; Max T. Wills, Auteur Année de publication : 1995 Article en page(s) : p. 53-59 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chimie analytique Composés organiques volatils Etudes comparatives Revêtements en phase aqueuse:Peinture en phase aqueuse Index. décimale : 667.9 Revêtements et enduits Résumé : The Cal Poly distillation modification of the Karl Fischer water determination of ASTM D 4017 gives accurate and precise water content of coatings and consequently better VOC values on waterborne paints. The precision appears to be substantially better than that obtained with previous methods. A relative reproductibility of 2.85% at the 95% confidence level was obtained on four coatings with water contents ranging from 32 to 72%. Azeotropic distillation of water with 1-methoxy-2-propanol followed by Karl Fischer titration of the distillate appears to be applicable to many different coatings types. The distillation offers several advantages, including the elimination of numerous potential interfering materials which are known to react with Karl Fischer reagent, the prevention to electrode fouling by polymer, and allows the use of the more general and extensively documented ASTM E 203 Karl Fischer titration method for water determination. Mathematical modeling shows that waterborne coatings with greater than 60% water content or VOC contents lower than about 160 g/L are extremely difficult to analyze using the existing ASTM methods for VOC analysis from a precision standpoint in which 10% or better reproductibility is desired. The 10% allowance presently in use by many air quality agencies should be replaced by a sliding tolerance scale which reflects the specific parameters of coating formulations. We suggest that the EPA and ASTM consider round-robin testing of the Cal Poly distillation method to confirm the results obtained in this study and to test the potential broader applicabillity of the method. We also suggest that Cal Poly evaluate extraction-dissolution water analysis (e.g., the Golton Method) and compare it against the distillation method in terms of accuracy, precision, and ease of use. The LASCT intends to initiate further studies to determine if the Cal Poly water method will reduce inaccuracies potentially caused by substances such as ammonia, ionic compounds, and additives, such as melamines and certain pigments. Note de contenu : - CAL POLY WATER METHOD : Procedure - Sample - Standard - Analysis and calculation - VOC VALUES OBTAINED WITH KNOWN SAMPLES - PREPARATION OF SAMPLES FOR ROUND-ROBIN ANALYSIS - ROUND-ROBIN DISCUSSION - CALCULATION OF THE VOC CONTENT - FORMULA FOR CALCULATION OF COATING VOC CONTENT Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18513 [article]

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