Three-Layer Preservative Film with Temperature-Controlled Release
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Solution Overview
Problem
Existing controlled-release antimicrobial packaging systems face issues with uncontrollable diffusion direction and insufficient release power for antimicrobial agents, leading to waste and poor preservation effects.
Innovation Solution
A three-layer film comprising a temperature-sensitive inner layer, a deformation intermediate layer, and a mechanical outer layer, assembled using layer-by-layer technology, which controls the direction and enhances the release power of antimicrobial agents through temperature and mechanical driving forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional antimicrobial packaging uses concentration difference for mass transfer, then the antimicrobial agent can be released to kill microorganisms, but the release direction is uncontrollable and causes waste of the antimicrobial agent
Solution Approach 1:
The packaging system is segmented into multiple functional layers: an inner layer containing antimicrobial agents, an intermediate layer with temperature-responsive pores, and an outer layer. This segmentation enables directional control of agent release toward the food surface rather than random diffusion into the environment.
Solution Approach 2:
The invention introduces temperature as an additional control dimension beyond concentration difference. By using temperature-responsive materials in the intermediate layer, the release direction and rate are controlled through thermal stimulation, creating a directed release pathway from the packaging toward the food surface.
2Reliability
If traditional antimicrobial packaging relies on concentration difference for release, then the agent can diffuse to food surface, but the mass transfer power is insufficient and decreases over time
Solution Approach 1:
The packaging system is pre-loaded with antimicrobial agents in the inner layer during manufacturing. The intermediate layer with temperature-responsive pores is pre-configured to open pathways when thermal stimulation is applied, enabling rapid agent release when needed without relying solely on gradual concentration-driven diffusion.
Solution Approach 2:
The invention changes the control parameter from concentration difference to temperature. By using temperature-responsive materials that undergo phase transitions or structural changes at specific temperatures, the mass transfer power is amplified and can be activated on-demand to overcome the insufficiency of concentration-driven release.
3Ease of operation
If controlled-release packaging uses temperature-sensitive polymer to reduce path resistance, then the antimicrobial agent can be released when stimulated, but the release direction remains uncontrollable
Solution Approach 1:
Different layers of the packaging are assigned different local qualities: the inner layer contains the antimicrobial agents, the intermediate layer has temperature-responsive pore structures for directional transport, and the outer layer provides structural support. This local differentiation ensures that when temperature stimulation occurs, agents are released in a controlled direction toward the food rather than diffusing randomly.
Solution Approach 2:
The intermediate layer with temperature-responsive pores acts as an intermediary between the inner layer containing agents and the outer environment. This intermediary layer controls both the timing and direction of release by opening pathways only when thermal stimulation is applied, preventing unordered diffusion while enabling controlled transport toward the food surface.
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 three-layer film effectively directs and amplifies the release of antimicrobial agents, optimizing preservation by ensuring timely and controlled release to the surface of fruits and vegetables, thereby improving storage efficacy and reducing microbial growth.
Implementation Method 1
a temperature-sensitive polyurethane (TSPU) antioxidant composite film with gas phase-controlled release, where a temperature is controlled to change a size of a free-volume hole and reduce a resistance for the release of an antimicrobial agent
Implementation Method 2
The intermediate layer is a deformation layer with an expansion and contraction property, which will expand with the rise of temperature and directly produce an extrusion stress on the inner and outer layers
Implementation Method 3
the antimicrobial active ingredient can be released from the surface of a polymer to the inside of a packaging system in the form of diffusion
Data Source
AI summary
In the present disclosure, a temperature-sensitive inner layer solution, a deformation intermediate layer solution, and a rigid outer layer solution are first prepared and spray-coated layer by layer on a surface of a fruit or vegetable, such that three preservative film layers are produced successively and can be used for the preservation of the fruit or vegetable.