Cross-linked polyol coated fertilizer release control
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Solution Overview
Problem
Current controlled release fertilizers are expensive to manufacture and lack the ability to customize release rate profiles effectively, often requiring significant amounts of coating materials and not being suitable for all fertilizer compositions.
Innovation Solution
A controlled release fertilizer composition using a particulate plant nutrient coated with a reaction product of an isocyanate and a modified polyol, where the modified polyol comprises castor oil cross-linked with sulfur, optionally including an unsaturated wax, to achieve a more controlled and customizable release rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional polymer coatings are used to control nutrient release, then release control is achieved, but manufacturing cost increases and coating material quantity required increases
Solution Approach 1:
The invention changes the chemical parameters of the coating material by using cross-linked polyols instead of traditional linear polymers. This structural modification alters the degradation kinetics, enabling controlled nutrient release with reduced coating material quantity while maintaining manufacturing efficiency
Solution Approach 2:
The invention employs a composite coating system comprising cross-linked polyol, isocyanate, and optionally wax. This composite structure combines the benefits of controlled degradation (from cross-linked polyol) with enhanced barrier properties (from isocyanate and wax), achieving effective release control with reduced overall coating material quantity
2Reliability
If traditional polymer coatings are used, then fertilizer encapsulation is achieved, but manufacturing cost increases
Solution Approach 1:
The invention modifies the chemical structure parameters by introducing cross-linking bonds in the polyol component, which enhances encapsulation integrity while using more cost-effective materials and processes compared to traditional synthetic polymers
Solution Approach 2:
The invention uses naturally derived cross-linked polyols that provide sufficient encapsulation functionality at lower cost than conventional synthetic polymers, accepting that the coating will degrade over time as part of the controlled release mechanism
3Reliability
If standard coating formulations are used, then fertilizer coating is achieved, but release rate customization is limited
Solution Approach 1:
The invention introduces dynamic adjustability to the coating system by varying the cross-linking degree, polyol molecular weight, and wax content. These dynamic parameter adjustments enable customization of release rates while maintaining reliable coating formation through the fundamental cross-linked polyol-isocyanate reaction mechanism
Solution Approach 2:
The invention enables release rate customization by changing key parameters including cross-linking density, polyol-to-isocyanate ratio, and wax addition levels. Each parameter adjustment fine-tunes the degradation and barrier properties to achieve desired release profiles for different agricultural applications
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 use of cross-linked polyols in the fertilizer coating results in a more controlled release rate, reducing the amount of coating materials needed and allowing for customizable release profiles, thereby enhancing efficiency and cost-effectiveness.
Implementation Method 1
the modified polyol comprises castor oil which is cross-linked with sulfur
Implementation Method 2
a reaction product of an isocyanate and a modified polyol
Data Source
AI summary
A controlled release fertilizer material comprising a particulate plant nutrient surrounded by a coating including a mixture of a cross-linked polyol and an isocyanate, and optionally a wax, is described. In some embodiments, the cross- linked polyol can be cross-linked with sulfur, oxygen, and/or a peroxide cross- linking moiety. In one embodiment the cross-linked polyol is castor oil cross-linked with sulfur.