Sulfide containing polyester coatings for agrochemical composition
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Solution Overview
Problem
Existing controlled release fertilizers (CRFs) lack biodegradability and effective moisture protection, failing to meet regulatory requirements and providing inconsistent nutrient release.
Innovation Solution
A biodegradable coating composition formed by the chemical reaction of monomers A and B, comprising GDMA, TMPTMA, PETMA, PETMP, TMPTMP, or GDMP with monomers having 5- or 6-membered cycloalkyl moieties and (meth)acrylate end groups, offering controlled nutrient release and biodegradability over 10-24 months.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymer coatings (alkyd, polyolefin, polyurethane) are used for controlled release fertilizers, then controlled nutrient release is achieved, but biodegradability is poor and regulatory requirements are not met
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by using sulfide-containing polyesters with specific molecular structures (containing -S- bonds and ester groups) that enable both controlled release and biodegradability, resolving the contradiction between release control and environmental compatibility
Solution Approach 2:
The invention uses composite coating materials combining sulfide groups with polyester backbones, creating a new material class that integrates the moisture barrier properties needed for controlled release with the biodegradability required by regulations
2Reliability
If thiol ester compositions are reacted with isocyanates to form polythiourethane coatings, then controlled release properties are achieved, but the thiourethane bond is resistant to hydrolysis and biodegradation
Solution Approach 1:
The patent extracts the isocyanate component from the thiol ester-isocyanate reaction system and instead uses sulfide-containing polyesters that can be hydrolyzed by microorganisms, eliminating the biodegradation resistance problem while maintaining coating stability
Solution Approach 2:
The invention adopts a coating material designed to be temporarily stable during fertilizer release but ultimately degradable, replacing the permanent stable polythiourethane with a biodegradable sulfide-polyester system that serves its function and then breaks down
3Object-generated harmful factors
If polyester dispersions based on aliphatic and aromatic units are used for coating, then some biodegradability is achieved, but barrier properties are poor and nutrient release is too rapid
Solution Approach 1:
The patent optimizes the polyester structure by incorporating sulfide groups and controlling molecular weight and composition to achieve the right balance between moisture barrier properties for controlled release and biodegradability for environmental compatibility
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 coating composition achieves at least 16% biodegradation within 10-24 months and controlled nutrient release, ensuring not more than 15% release in the first 24 hours and complete release within 30 days, meeting regulatory standards and providing sustained nutrient supply.
Implementation Method 1
the coating composition or the coated agrochemical composition has desired biodegradability behavior
Implementation Method 2
providing controlled nutrient release, ensuring not more than 15% release in the first 24 hours and complete release within 30 days
Data Source
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AI summary
A coating composition comprising an adduct formed by chemical reaction of a monomer containing poly-thiol with a monomer containing one or more unsaturated carbon - carbon bond; more particularly relates to coated agrochemical compositions coated with said coating composition.