Friday, April 11, 2008

Melamine Formaldehyde Adhesive

A melamine formaldehyde adhesive (also commonly called a melamine glue or an MF) is a condensation product of unsubstituted melamine and formaldehyde.

Melamine formaldehyde resin have much in common with urea formaldehyde resin; they were, however, introduced many years after urea resin and have not attained great importance as adhesives. Melamine resin is, however, widely used as textile finished and in the manufacture of decorative laminates and plastic molding.

The melamine formaldehyde reaction in its relation to adhesives.

The reaction between melamine and formaldehyde has been studied by Kohler, and by Gams, Widmer and Fisch. The process of resinification are analogous to those of urea formaldehyde, that is related to urea resins therefore applied broadly to melamine resins, the reaction being similarly governed by the five factor; molecular ratio, pH value, temperature, concentration and time.

In the preparation of adhesives, melamine and formaldehyde in a molecular ratio 1 : 2.5 to 1 : 3.5, are reacted at a pH of between 8.0 to 9.0 and a temperature at or near to the boiling point. As with the urea reaction, condensations follows the formation of methylol compounds, and as resinification proceeds the solution become more and more hydrophobic. The reaction is continued until water toleration at room temperature is such that at least an equal volume of water can be added without precipitation occurring.

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