Patent Number: 6,166,204

Title: Crystalline melamine

Abstract: Multicrystalline melamine powder having the following properties: specific surface area: 0.7-5 m.sup.2 /g level of oxygen-containing components <0.7 wt % color APHA less than 17 melamine: >98.5 wt % melam: <1.3 wt % Multicrystalline melamine powder obtainable via a high-pressure process in which solid melamine is obtained by the melamine melt being transferred to a vessel where the melamine melt is cooled with an evaporating cooling medium, the melamine melt having a temperature between the melting point of melamine and 450.degree. C. being treated with 0.1-15 mol of ammonia per mole of melamine and then being sprayed via spraying means and cooled with an evaporating cooling medium within a vessel in an ammonia environment at an ammonia pressure of 0.1-25 MPa, the melamine melt being converted into melamine powder having a temperature between 200.degree. C. and the solidification point of melamine, the melamine powder then being cooled to a temperature below 50.degree. C., the powder being set in motion mechanically over at least part of the cooling range and being cooled directly or indirectly, and the ammonia pressure being released at a temperature below 270.degree. C.

Inventors: Tjioe; Tjay T. (Sittard, NL)

Assignee: DSM N.V.

International Classification: C07D 251/62 (20060101); C07D 251/00 (20060101); C07D 251/60 ()

Expiration Date: 12/26/2017