MicroencapsulationR.T.Dodge Co.R.T.Dodge Co.

Coacervation

Coacervation: The phenomenon of forming a liquid rich in polymer phase in equilibrium with another liquid phase. This involves the classic method developed by National Cash Register (NCR) for carbonless copy paper as well as many other applications. For simplicity’s sake we will describe this method as it might relate to applying a gelatin wall.

First the gelatin is dissolved in water forming a ‘sol’. The solution is then heated to solubilize the gelatin. A liquid or solid core is then stirred in at a rate which will produce the desired droplet size and/or the proper dispersion. The dispersion is then treated by one of a number of means so as to cause the gelatin to come out of solution in a highly swollen, solvated state.

Further treatment of our slurry causes the liquidous gelatin “coacervate” to deposit around the core material. The formed capsules can then be treated to harden the gelatin walls.

Besides gelatin we us other wall materials to encapsulate liquid or solid materials. Some of those wall material include but are not limited to Urea Formaldehyde (UF), Melamine Formaldehyde (MF), Poly-vinyl Alcohol (PVA) and other proprietary methods which Dodge utilizes.

Phase Separation

Even though this is one of the most popular encapsulation methods, there are certain variables that this method is subjected to. Some of those variables are, but are not limited to the solubility of the core material, whether the final product should be dried and isolated or left in a slurry and the application in which the capsules will be used.

Wall Materials include but not limited to,

 

 

 

 

Coacervation/Phase Separation

 


Insitu Polymerization

Wall Material include but not limited to,

  • Aminoplast / Thermoset & Variations
  • Poly (methyleneurea) PMU
  • Poly (oxymethyleneurea) POMU
  • Poly (oxymethylenemelamine) POMM
Coacervation/Insitu Polymerization
   

Poly Condensation

Basic Process

Coacervation/Poly Condensation