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US 5,795,507 AGranted
Preparation of pigmented melamine-formaldehyde polymer beads
AssigneeMelamine Chemicals, Inc.
InventorsGeorge M. Crews, Ji Shen
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Abstract
Spherical porous polymer pigment beads of melamine formaldehyde resin with uniform diameter were prepared by a water-in-oil emulsion polymerization of colored methylolmelamine aqueous solution. The dyes combined with methylolmelamine to give an excellent hue stability. The pigmented melamine formaldehyde beads (PMFB) with mean size of 3-6 micron as an organic pigment showed excellent weather and heat stability, chemical resistant properties and disperability in an application medium.
Claims10
Method of producing pigment beads of melamine formaldehyde resin comprising the steps of
- (i) forming a mixture of formaldehyde, melamine and water,
- (ii) heating said mixture of (i) and adding a dye to form a colored methylolmelamine solution,
- (iii) adding an organic solvent and emulsifying agent to said methylolmelamine solution (ii), said emulsifying agent having an HLB of 8.5-9.3, and
- (iv) heating (iii) with stirring to provide pigmented spherical shaped particles of crosslinked melamine resin.
1 more element
Dependencies are inferred from the claim text.