Process for the production of polyurea encapsulated fertilizer particles and the encapsulated fertilizer particles produced by this process

A process for producing encapsulated, slow release, fertilizer particles comprising:

• 1) applying b) an organic polyisocyanate component onto fertilizer particles containing at least one water soluble plant nutrient, to form isocyanate coated fertilizer particles,
• 2) applying a) a gaseous isocyanate-reactive component which contains at least two amine groups, onto the isocyanate coated fertilizer particles from step 1) by contacting the isocyanate coated fertilizer particles with a volatilized amine group containing isocyanate-reactive compound to yield polyurea encapsulated fertilizer particles,
• and, optionally,
• 3) repeating steps 1) through 2) as many times as necessary, wherein the encapsulated fertilizer particles from step 2) are substituted for the fertilizer particles in step 1) above,
• so as to form encapsulated fertilizer particles which contain from about 0.5% to about 15% by weight of polyurea, based on the total weight of the encapsulated fertilizer particles.

A process for producing encapsulated, slow release, fertilizer particles comprising:

• 1) sparsely applying a) water to fertilizer particles containing at least one water soluble plant nutrient, to form water coated fertilizer particles,
• immediately followed by:
• 2) applying b) an organic aromatic diisocyanate component which contains isocyanate-groups onto the water coated fertilizer particles from step 1) to yield polyurea encapsulated fertilizer particles,
• and, optionally,
• 3) repeating steps 1) through 2) as many times as necessary, wherein the encapsulated fertilizer particles from step 2) are substituted for the fertilizer particles in step 1) above,
• so as to form encapsulated fertilizer particles which contain from about 0.5% to about 15% by weight of polyurea, based on the total weight of the encapsulated fertilizer particles.

A process for producing encapsulated, slow release, fertilizer particles comprising:

• 1) applying b) an organic aromatic diisocyanate component which contains isocyanate-groups to fertilizer particles containing at least one water soluble plant nutrient, to form isocyanate coated fertilizer particles,
• immediately followed by:
• 2) applying a) water onto the water isocyanate coated fertilizer particles from step 1) to yield polyurea encapsulated fertilizer particles,
• and, optionally,
• 3) repeating steps 1) through 2) as many times as necessary, wherein the encapsulated fertilizer particles from step 2) are substituted for the fertilizer particles in step 1) above,
• so as to form encapsulated fertilizer particles which contain from about 0.5% to about 15% by weight of polyurea, based on the total weight of the encapsulated fertilizer particles.