Amino resins.

Amino resins

• Amino resins are condensation products obtained by reaction of formaldehyde with nitrogen bearing compounds such as aniline, amides. For example urea formaldehyde, melamine formaldehyde.
• Urea formaldehyde is prepared by condensation reaction between urea and formaldehyde in acidic or alkaline medium.
• The first product formed during the formation of resin is monomethylol and dimethylol ureas.

  

  Synthesis of amino resins step 1.

• Polymerisation can take place from mono or di methylol urea or possibly through both with the formation of long chain.

  

  Synthesis of amino resins step 2

• The formation of melamine formaldehyde resin is similar to formation of urea formaldehyde.
• Amino resins are clear and colourless.
• They are harder and have high strength but lower heat and moisture resistance than phenolics.
• The melamine formaldehyde resins have high moisture, heat and ageing resistance than urea formaldehyde resins but are usually costly.
• Both urea formaldehyde and melamine formaldehyde resins are used as adhesives.
• Amino resins are also used as coatings and laminates. Next

  

  Uses of amino resins.