MELCROSS-21 is designed as good crosslinker for most polymers which contained hydroxyl and amide groups.  But there is a little limit on carboxyl groups.  High methylol group derives good reactivity and water soluble properties for the coating formulations.This resin is reduced in isobutanol and can be utilized as crosslinking agents for both solvent and water based coatings.

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Introduction

MELCROSS-21 crosslinking agent is a commercial grade of methylated melamine-formaldehyde resin with a high methylol  functionality content  and insolved in the isobutanol solvent. The advantages of MELCROSS-21 are rapid cure,  higher solids enamels,  gloss and gloss retention,  good stability, chemical resistance in coating areas.

This resin requires only weak acid catalyst for cure at normal baking schedules.   Used in both aqueous and solvent-born coatings due to excellent balance between compatibility and cure response.  Showing a high tendency towards self condensation . To control the stability, you can use tertiary amins for neutralisation and PH adjustment. 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, low levels of para toluene sulfonic acid catalyst.
Acid catalyzed coatings may be cured as low as 100°C.

MELCROSS-21 cure similary to butylated melamine resins.
They also have a tendency to self-condense.  Higher film hardness may be easily obtained by raising the level of amino crosslinking agent.