14 августа, 2015 
Malyar Catalysts are used in a number of applications, the type and selection depend on the type of application and the crosslinking chemistry involved.
The reaction between an hydroxy acrylic and a butylated melamine formaldehyde resin normally proceeds most effectively at 120°C during a 30 minute bake cycle. Higher temperatures can be used, but in order to avoid deterioration in film performance due to overcure, the times are incrementally reduced as the temperature increases.
Curing temperatures below 120°C are obtained by additions of acids, such as para-toluene sulphonic acid, acid butyl phosphate, acid butyl maleate or special proprietory catalysts. The combination of acid catalysis and a highly reactive melamine formaldehyde resin can result in curing temperatures as low as 80°C. In such cases the paint formulator must pay careful attention to pigment and viscosity stabilities to ensure that flocculation of the pigment does not occur. Viscosity is normally controlled by primary alcohols in the solvent blend (at least 20% of total solvent).
Hexamethoxymethyl melamine (HMMM) resins are less reactive than butylated melamine resins and always require the incorporation of acid catalysts to cure the coating. Para-toluene sulphonic acid (1-2% on total resin) is used extensively in hydroxy acrylic/HMMM formulations.
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