Attrition-resistant, controlled release fertilizers

• US 4,804,403 A
• Filed: 08/06/1987
• Issued: 02/14/1989
• Est. Priority Date: 08/18/1986
• Status: Expired due to Term

• Current Assignee: Agrium Polymer Coatings Corp.
• Original Assignee: Melamine Chemicals, Inc. (CF Industries Holdings Incorporated)
• Inventors: Moore, William P.
• Primary Examiner(s): Lander, Ferris H.
• Application Number:
  US07/082,236
• Time in Patent Office: 558 Days
• Field of Search: 71/1, 71/28-30, 71/64.12, 71/64.13, 71/64.11, 71/93
• US Class Current: 71/28
• CPC Class Codes: C05C 11/00 Other nitrogenous fertilisers
• CPC Class Codes: C05C 9/00 Fertilisers containing urea or urea compounds
• CPC Class Codes: C05C 9/02 containing urea-formaldehyde condensates
• CPC Class Codes: C05G 5/37 layered or coated with a polymer
• CPC Class Codes: C08G 18/3829 containing ureum groups
• CPC Class Codes: C08G 18/4213 from terephthalic acid and dialcohols
• CPC Class Codes: C08G 18/664 with compounds of group C08G18/3203

Abstract

An attrition-resistant, controlled release fertilizer comprising a water-soluble central mass containing nucleophilic reactive functional groups surrounded and chemically bonded to a base coating formed by reacting a molecular excess of a coupling agent with the nucleophilic groups of the central particles, and a water-insoluble layer, surrounding and chemically bonded with the base coating, formed by the reaction and polymerization of the excess functional groups of the coupling agent used in forming the base coating is described. A preparation method is provided.

Claims

1. An attrition-resistant, controlled release fertilizer composition comprising the reacted moieties of Component A which is a water-soluble central mass of plant food compound in particulate form containing reactive functional groups amounting to at least 10%;

Component B which is a monomer-type component having reactive functionality; and

Component C which is present as a water-insoluble polymeric sealing layer;

said Components A, B and C being selected in order that the reactive functionality of Component B will react with the reactive functionality of each of Components A and C, and with the ratios of said Components A, B and C being selected whereby Component B is present in an amount sufficient to provide reaction sites for reaction with substantially all of the reactive functionality at the surface of said particles of Component A and to react with the reactive functionality on Component C, thereby forming particles of Component A having a sealing layer of Component C thereon and with Components A and C being chemically linked together through Component B.

2. The composition of claim 1 wherein said reactive functionality of Components A and C are nucleophilic reactive groups.

3. The composition of claim 2 wherein the nucleophilic reactive groups of Component A are --NH₂ groups.

4. The composition of claim 3 wherein Component B is a polyisocyanate and Component C includes hydroxy groups.

5. An attrition-resistant, controlled release fertilizer particle composition, comprising:

(A) a water-soluble central mass of plant food compound containing nucleophilic functional groups amounting to at least 10 percent;

(B) a base component, surrounding and chemically bonded to the central mass formed by reacting a molecular excess of a liquid polyfunctional electrophilic monomeric or oligomeric compound with the nucleophilic functional groups of the central mass; and

(C) a water-insoluble sealing layer, surrounding and chemically bonded to said base component, formed by the reaction and polymerization of the excess polyfunctional electrophilic compound of the base component with an amount of anhydrous liquid organic nucleophilic monomeric or oligomeric compound.

6. An attrition-resistant, controlled release fertilizer particle composition, comprising:

(A) a water-soluble central mass of plant food compound containing reactive functional groups amounting to at least 10 percent, and

(B) a base component, surrounding and chemically bonded to the central mass formed by reacting a molecular excess of a polyfunctional monomeric-type compound with the reactive functional groups of the central mass, said base component having residual reactive functionality.

7. A stepwise method of producing an attrition-resistant particulate fertilizer comprising:

(A) surrounding and chemically bonding particles of water-soluble fertilizer material, containing at least 10 percent reactive functional groups, with a base coating, by applying a molecular excess of a polyfunctional coupling agent to a mobile mass of the particles of fertilizer at a temperature between 30°

C. and 160°

C., and holding for a period of time between one and 60 minutes; and

(B) surrounding and chemically bonding said base coating with a water-insoluble sealing layer by reaction and polymerization of the excess polyfunctional coupling agent of the base coating with a reactive material having functional groups reactive with the functional groups of said coupling agent to form a water-insoluble polymer, the ratio of functional groups on said reactive material and coupling agent being between 1 and 3, by applying the reactive material to a mobile mass of base coated particles at a temperature between 60°

C. and 160°

C., and holding for a period of time between one and 60 minutes.