25 сентября, 2015 
Malyar The various aminoplastic resins are the most important class of adhesives in the wood — based panels industry, especially for the production of particleboards and medium density fibreboard (MDF), and partly also for oriented strandboard (OSB), plywood, block — boards, and some other types of wood panels. They are also used in the furniture industry as well as in carpenters’ shops.
Aminoplastic adhesive resins are formed by the reaction of urea and/or melamine with formaldehyde. Based on the raw materials that are used various types of resins can be prepared, namely:
urea-formaldehyde resin melamine-formaldehyde resin melamine-urea-formaldehyde cocondensation resin melamine fortified UF resins mixture of an MF and a UF resin
melamine-urea-phenol-formaldehyde cocondensation resin.
The most important parameters for the aminoplastic resins are:
(a) The type of monomers used.
(b) The relative molar ratio of the various monomers in the resin:
F/U molar ratio of formaldedhyde to urea F/M molar ratio of formaldehyde to melamine F/(NH2)2 molar ratio of formaldehyde to amide or amine groups, whereby urea counts for two NH2 groups, and melamine for three NH2 groups.
(c) The purity of the different raw materials, e. g., the level of residual methanol or formic acid in formaldehyde, biuret in urea, or ammeline and ammelide in melamine.
(d) The reaction procedures used, e. g.
the pH variation sequence
the temperature variation sequence
the types and amount of alkaline and acidic catalysts
the sequence of addition of the different raw materials
the duration of the different reaction steps in the cooking procedures.
The production of aminoplastic adhesive resins is usually a multistep procedure where both alkaline and acidic steps occur. Aminoplastic resins can be prepared in a variety of different types for all the different needs in wood bonding. This can be achieved by just using the three main monomers mentioned above and varying the preparation procedure.
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