Benzoguanamine-formaldehyde polymer

For the purposes of this chapter, aminopolymers are defined as polymers formed by the interaction of amines or amides with aldehydes. Of the various polymers of this type which have been investigated, only two are currently of appreciable commercial importance, namely urea-formaldehyde and melamine-formaldehyde polymers. In addition, melamine-phenol-formaldehyde and benzoguanamine-formaldehyde polymers find limited application. In the past there has been some commercial interest in thiourea-formaldehyde and aniline-formaldehyde polymers but these products are now of little importance. The aforementioned polymers form the contents of this chapter. 

Alkylated melamine-, urea-, and benzoguanamine-formaldehyde resins are the principal cross-linking agents in many industrially applied baked coatings. They are combined with acrylic, alkyd, epoxy, and polyester resins. The amide, hydroxyl, or carboxyl groups of these backbone polymers are used as functional sites for reaction with the amino resin. 

The term aminoplastics has been coined to cover a range of resinous polymers produced by interaction of amines or amides with aldehydes. Of the various polymers of this type that have been produced there are two of current commercial importance in the field of plastics, the urea-formaldehyde and the melamine-formaldehyde resins. There has in the past also been some commercial interest in aniline-formaldehyde resins and in systems containing thiourea but today these are of little or no importance. Melamine-phenol-formaldehyde resins have also been introduced for use in moulding powders, and benzoguanamine-based resins are used for surface coating applications. 

Amino polymers are derived from various amines and formaldehyde. Example amines used for these polymers are urea, benzoguanamine, melamine, and aniline, with the most common forms being urea and melamine resins. The formation of amino resins is complex, because the addition and condensation products of the amine and formaldehyde take multiple pathways involving by-products and side reactions. There is no general formula for a urea-based resins. The early reaction products are similar to those formed in phenolic resins or polyurethanes, but these early reaction products react further to form the final high polymer. Only the final reaction products will be considered in this section. 

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