Biodegradable Fertilizer Coating for Controlled Nutrient Release

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Solution Overview

Problem

Conventional coated granular fertilizers face issues with biodegradability and release controllability, with coatings either taking too long to decompose or releasing fertilizer components too quickly, leading to environmental fragmentation or inefficiency.

Innovation Solution

A coated granular fertilizer comprising a biodegradable resin and a wax with an ester group, where the wax is less than 80% of the coating, balanced with a specific mass ratio, to achieve both biodegradability and controlled release of fertilizer components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a coating layer containing biodegradable resin and polyolefin wax is used, then the coating has biodegradability, but it takes a long period of time for the coating layer to be decomposed in the natural environment and fragments remain

Engineering Contradiction:

Improvebiodegradability of coatingVSAvoiddecomposition time of coating

Core Design Contradiction:

Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical composition parameters of the coating by selecting specific biodegradable resins (polylactic acid, polyhydroxyalkanoate, polybutylene succinate, or their copolymers) and controlling their molecular weight and composition ratios to achieve optimal decomposition rate while maintaining coating integrity during fertilizer release

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating material by combining biodegradable resins with specific ratios (5-80 wt% biodegradable resin with 20-95 wt% other components) to achieve both sufficient mechanical strength for fertilizer containment and controlled biodegradation rate for complete environmental decomposition

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If polyhydroxyalkanoate or polybutylene succinate is used as coating material, then the coating has disintegrability and can be easily decomposed in the natural environment, but the permeability of moisture into the inside of the fertilizer is too high and fertilizer components are released for a long period of time

Engineering Contradiction:

Improvedecomposition time of coatingVSAvoidrelease period of fertilizer

Core Design Contradiction:

Duration of action of stationary objectVSDuration of action of moving object

Solution Approach 1:

The patent applies different functional properties to different aspects of the coating: the coating provides high moisture permeability for rapid biodegradation and environmental decomposition, while simultaneously providing controlled fertilizer release through the granular structure and coating thickness optimization, allowing local variation in performance characteristics

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes the inherent porous structure of biodegradable resin coatings to allow moisture penetration for rapid decomposition, while the controlled porosity and coating thickness (3-20 mass% of total fertilizer) regulate the diffusion rate of fertilizer components, achieving both fast decomposition and controlled release

Inventive Principle:

Principle #31Porous materials

3Duration of action of stationary object

If biodegradable plastics are used as coating material, then the coating has high water vapor permeability, but the release rate of fertilizer components is high and release suppression is insufficient

Engineering Contradiction:

Improvedecomposition time of coatingVSAvoidrelease rate of fertilizer

Core Design Contradiction:

Duration of action of stationary objectVSQuantity of substance

Solution Approach 1:

The patent applies preliminary coating treatment to the granular fertilizer surface, creating a barrier layer that initially suppresses fertilizer release. The coating is designed to maintain this barrier function during the critical early period, then progressively degrade over time as moisture penetrates and biodegradation begins, providing time-dependent release control

Inventive Principle:

Principle #10Preliminary action

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 solution provides a coated granular fertilizer with excellent biodegradability and controlled release of fertilizer components, ensuring minimal environmental impact and sustained nutrient availability.

Implementation Method 1

the coating contains a biodegradable resin (A) and at least one wax (B) selected from the group consisting of a natural wax (b1) having an ester group and a modified product thereof (b2)

Methodology Applied

Scientific EffectBiodegradation: Decomposition (biological)

Implementation Method 2

release controllability of the fertilizer components

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 3

release rate of the fertilizer components is high

Methodology Applied

Scientific EffectErosion: Erosion

Data Source

PatentEP4703340A1Coated granular fertilizer

Publication Date: 2026.03.04 JCAM AGRI

Figure 1

AI summary

One embodiment of the present invention is a coated granular fertilizer including a granular fertilizer and a coating that covers a surface of the granular fertilizer, in which the coating contains a biodegradable resin (A) and at least one wax (B) selected from the group consisting of a natural wax (b1) having an ester group and a modified product thereof (b2), and the wax (B) is contained in an amount of less than 80 mass% in 100 mass% of the coating.