Urethane coating components catalysts

Raw Materials for Urethane Coatings Isocyanate Components Di- and Polyhydroxy Components Chain Extenders and Cross-linkers Catalysts... 

There are two specific groups in this series of products (a) neutral urethane polyethers (112) that have to be activated with catalysts when used as second components in urethane coatings, which can be easily transformed into isocyanate-terminated polymers when reacted with additional isocyanate (b) basic urethane polyethers (113. 114) having hydroxyls activated by tertiary amine nitrogen present in the chemical chain of the product and that are very reactive second components of urethane coatings. They can also be converted into isocyanate-terminated polymers, but their stability is very limited (12-24 h). They are stable when immediately blocked by means of phenol, alcohols, or other suitable blocking agents. 

Two-Package Polyol Urethane Coatings (ASTM Type 5). Two-package polyol urethane coatings consist of isocyanate-terminated adducts of polymers that are cured by reaction with di- or polyfunctional hydroxyl-containing materials. The latter may consist of low- to medium-weight polyols with a polyester, polyether, polyether urethane, or castor oil backbone. When the two components (OH- and NC0-) are mixed together, they have only a limited pot life. Therefore, the components are mixed prior to application. Catalysts may be used to speed up the cure either for room temperature or oven cure. 

Chem. Descrip. Bismuth carboxylate in 2-ethylhexanoic acid Uses Catalyst for blocked isocyanate and two-component urethane coatings, coil coatings, aerospace, automotive, urethane coatings for plastics... 

Chem. Descrip. Zirconium chelate in 2,4-pentanedione Uses Catalyst for two-component urethane coatings (automotive topcoats, high performance maintenance coatings, aerospace coatings, coatings for structural plastics)... 

Urethane An important resin in the coatings industry. A true urethane coating is a two-component product that cures when an isocyanate (the catalyst) prompts a chemical reaction that unites the components. 

Two-Package Coatings with Aminoformaldehvde Cure. One component consists of a hydroxyl-terminated urethane prepolymer while the other component is an alkyl ether (usually methyl or butyl ether) of a methylolmelamine or methylolurea derivative (melamine- or urea-formaldehyde condensation products or derivatives thereof) (140, 141). Various catalysts may be employed to accelerate the heat cure (. 125 C) and to lower the curing temperature. Curing results by splitting off of the respective alcohol, as shown ... 

Acrylic urethanes are used widely in the coating of plastic components, primarily as a clear or pigmented topcoat for basecoated or primed plastics. Clearcoats are formulated with aliphatic polyisocyanates. The addition of a UV absorber and a hindered amine light stabiliser further improve the photostability. Catalysts for the reaction fall into two categories, namely metallic salts and tertiary amines. 

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