Cymel 370 Cytec Crosslinking / Coupling / Curing Agents Acrylic/Acrylate Resins Alkyd Resins Polyester Coatings >> Solventborne Coatings >> Waterborne Coil Coating General Industrial /Maintenance Wood & Furniture Coatings Isobutanol CYMEL 370, 373 and 380 resins are excellent crosslinking agents for hydroxyl and amide-containing polymers. They are less efficient with carboxyl-containing polymers. ADVANTAGES Fast cure response Very high gloss Good stability Higher solids Chemical resistance APPLICATION AREAS General purpose enamels Coil coating Exempt solvent coatings Wood conversion varnishes Water-based coatings These three crosslinking agents are similar in composition, but dissolved in different solvents at different solids levels. CYMEL 370 and 380 resins are reduced in isobutanol solvent, while CYMEL 373 resin is dissolved in water. Application areas and performance of these three products are, therefore, very similar. CYMEL 370 resins and CYMEL 380 resins can be utilized as crosslinking agents for both solvent and water-based coatings. CYMEL 373 resin was designed especially for water-based coatings, such as emulsions or solutions. CYMEL 370, 373 and 380 resins require only weak acid catalysis for cure; a low acid number in an alkyd or acrylic resin is sufficient. The cure reaction can be additionally catalyzed with weak organic or inorganic acids such as maleic, citric, phosphoric or alkyl phosphoric acids, such as CYCAT® 2296-9 catalyst, low levels of p-toluol sulfonic acid or CYCAT® 24040 catalyst. Acid catalyzed coatings may be cured as low as 215°F (102°C). These CYMEL resins cure similarly to butylated melamine - formaldehyde resins. They also have a tendency to selfcondense. Higher film hardness may therefore be easily obtained by raising the level of amino crosslinking agent. SOLVENT-BASED COATINGS CYMEL 370 and 380 resins may be used as a direct replacement for butylated melamine-formaldehyde resins in solvent-based coatings. To achieve optimum performance, a ladder study should be conducted. Because of their limited solubility in aliphatic hydrocarbons, the solvent composition needs some polar solvent. Typical application areas for CYMEL 370 and CYMEL 380 resins in solvent-based coatings include general purpose spray coatings, coil coatings and metal decorating enamels. WATER-BASED COATINGS CYMEL 370, 373 and 380 resins are compatible with most water-soluble resins, dispersions or emulsions. For optimum stability, it is essential that a t-amine such as triethylamine or dimethylaminoethanol be used for neutralization and pH adjustment. As with any amino crosslinking agent, a pH between 7.0 and 8.5 should be maintained to achieve stability. In water-based coatings, the high acidity of the resins used may catalyze the CYMEL 370, 373 and 380 resins to give hard films at 250°F (121°C). At 250°F (121°C), the reaction with only carboxyl-group containing polymers is incomplete. A temperature of at least 275°F (135°C) is required to achieve humidity resistance and exterior durability. A preferred water soluble polymer for CYMEL 370, 373 and 380 resins should contain, in addition to carboxyl groups, hydroxyl or amide groups for optimum reactivity. The enamel stability of CYMEL 370, 373 and 380 resins is poorer than that of a fully methylated resin such as CYMEL 303 hexamethoxymethylmelamine. However, CYMEL 373 resin will provide better stability in water reducible systems than will CYMEL 370 or 380 resins. CYMEL 370, 373 and 380 resins may be used in waterbased conversion varnishes to improve the water resistance of a methylated urea-formaldehyde such as BEETLE® 1 60 resin or BEETLE® 1 65 resin. A level of one (1) part CYMEL 370, 373 or 380 resin to four (4) parts BEETLE 60 resin or BEETLE 65 resin is sufficient. Such a combination will cure under the typical conversion varnish baking schedule. CYMEL 370, 373 and 380 resins provide better stability in emulsion systems in AEROTEX® 1M-3, CYMEL1 385 or CYMEL1 481 resins. SOLUBILITY IN ORGANIC SOLVENTS Alcohols CYMEL 370 Resin CYMEL 373 Resin CYMEL 380 Resin Methanol + + + Ethanol + + + Isopropanol + + + n-Butanol + - + Isobutanol + - + Glycol and Glycolethers Ethylene glycol + + + Propylene glycol + + + Ketones Methylethel ketone + + + Methylisobutyl ketone + - + Isophorone + - + Hydrocarbons Toluene + - + Xylene + - + Aromatic2 150 Solvent - - - VM & P Naphtha - - - Hexane - - - Other Solvents Water ± ± ± Symbols: + = Soluble ± = Partially Soluble - = Insoluble FDA STATUS CYMEL 370, 373 and 380 resins are FDA approved under Sections 175.300 and 176.170 of the regulations of the Food Additives Amendment to the Federal Food, Drug and Cosmetic Act. These sections should be consulted for data on extractives limitations. Excellent crosslinking agent for hydroxyl and amide-containing polymers. Less efficient with carboxyl-containing polymers. Provides fast cure response, very high gloss, good stability, high solids, chemical resistance. Reduced in isobutanol solvent. Can be utilized as crosslinking agents for both solvent and water-based coatings. Requires only weak acid catalysis for cure; a low acid number in an alkyd or acrylic resin is sufficient. Has a tendency to selfcondense. Higher film hardness may therefore be easily obtained by raising the level of amino crosslinking agent. May be used as a direct replacement for butylated melamine-formaldehyde resins in solvent-based coatings. Typical application areas for it in solvent-based coatings include general purpose spray coatings, coil coatings and metal decorating enamels. Compatible with most water-soluble resins, dispersions or emulsions. For optimum stability, it is essential that a t-amine such as triethylamine or dimethylaminoethanol be used for neutralization and pH adjustment. As with any amino crosslinking agent, a pH between 7.0 and 8.5 should be maintained to achieve stability. Can be used for general purpose enamels, coil coating, exempt solvent coatings, wood conversion varnishes, water-based coatings.