Benzoguanamine Formaldehyde (BF) Resins

Properties and Applications

Benzoguanamine formaldehyde resins (BF) are crosslinkable triazine-type aminoplasts. They contain alkoxymethyl functional groups which readily react with resins containing hydroxyl, amide or carboxyl functional groups yielding three-dimensional thermoset polymer networks. The average functionality is lower than that of melamine resins because there are only two amino groups instead of three per triazine ring. Thus functional polymers cured with BF resins have typically a lower crosslink density than polymers cured with (etherified) melamine-formaldehyde (MF) and therefore have improved film flexibility and toughness.

Highly methylated/ethylated/butylated benzoguanamine resins are compatible with a large number of resins including many acrylics, alkyds, polyesters and epoxies.¹ Reactive polymers crosslinked with BF resins have typically higher chemical resistance to alkalines and better adhesion properties than polymers cured with MF resins. On the downside, they have lower UV light resistance and thus are not recommended for exterior applications.^1,2 They are also more expensive than MF resins.

Etherified benzoguanamine-formaldehyde resins are widely employed to crosslink industrial thermosetting resins, including alkyds, epoxies, and polyester-polyols. They are often blended with MF resins to lower cost. Important applications include flexible and chemical-resistant primers; can, coil and container coatings; as well as appliance finishes.

Manufacturers & Distributors

¹Allnex Amino Crosslinker Product Guide - Cymel and Setamine Resins (2017)
²BF resins have UV-absorbing phenyl groups attached to the triazine ring which makes the polymer more sensitive to UV degradation.