Polyurethane Encapsulated Fertilizer Prevents Pesticide Transfer
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Solution Overview
Problem
Conventional encapsulation methods for granular fertilizers with herbicides, such as pendimethalin, result in transfer issues due to volatility, adhesion problems, and incomplete coverage, leading to waste and health risks, with existing methods causing herbicides to sublime, melt, or vaporize, and inhibiting controlled release.
Innovation Solution
An encapsulated particle comprising a fertilizer core coated with a polyurethane layer formed from a reaction mixture of isocyanate and polyol, which inhibits pesticide transfer and ensures controlled release, with the reaction occurring at a temperature below the volatility point of the pesticide, preventing transfer and agglomeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encapsulation methods are used to prevent herbicide transfer, then the herbicide is enclosed, but the herbicide sublimes, melts, and/or vaporizes during the encapsulation process
Solution Approach 1:
The patent changes the temperature parameter of the encapsulation process by using a polyurethane formation reaction that proceeds at ambient or controlled low temperatures, preventing the herbicide from reaching its sublimation, melting, or vaporization points while still achieving effective encapsulation
Solution Approach 2:
The patent introduces polyurethane as an intermediary material that forms a protective layer around the herbicide-coated fertilizer granules. This polyurethane layer acts as a mediator that prevents direct contact between the herbicide and external surfaces, thereby preventing transfer while maintaining herbicide integrity
2Reliability
If conventional encapsulants are used to prevent herbicide transfer, then encapsulation is achieved, but controlled release of the herbicide and fertilizer is inhibited
Solution Approach 1:
The patent modifies the chemical and physical parameters of the encapsulant by using polyurethane with specific molecular weight, functionality, and crosslinking density. These parameter changes create a matrix that is sufficiently stable to prevent transfer but sufficiently permeable or degradable to allow controlled release of the herbicide and fertilizer over time
Solution Approach 2:
The patent creates a composite structure where the polyurethane encapsulant is combined with the herbicide and fertilizer granules. This composite material system integrates the protective properties of polyurethane with the functional properties of the agrochemicals, enabling both transfer prevention and controlled release
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The polyurethane layer effectively prevents pesticide transfer to surfaces and ensures consistent, controlled release of both the fertilizer and herbicide, reducing waste and production costs while maintaining the herbicide's effectiveness.
Implementation Method 1
The polyurethane layer comprises the reaction product of the isocyanate and the polyol
Implementation Method 2
The polyurethane layer inhibits the transferrable-pesticide from transferring to a surface different from the core particle when the encapsulated particle physically contacts the surface
Data Source
AI summary
An encapsulated particle comprises a core particle, a transferrable-pesticide disposed about the core particle, and a polyurethane layer disposed about the transferrable-pesticide. The core particle comprises a fertilizer, such as urea. The transferrable-pesticide can comprise a dinitroaniline, such as pendimethalin. The polyurethane layer is generally formed from a reaction mixture having a maximum temperature of no greater than about 30° C. The polyurethane layer inhibits the transferrable-pesticide from transferring to a surface different from the core particle when the encapsulated particle physically contacts the surface. A method of forming the encapsulated particle comprises the steps of encapsulating the core particle with the transferrable-pesticide to form an intermediate-particle, combining an isocyanate and a polyol to form the reaction mixture, and encapsulating the intermediate-particle with the reaction mixture to form the polyurethane layer of the encapsulated particle. The polyurethane layer comprises the reaction product of the isocyanate and polyol.