Temperature-Sensitive Magnetic Composition Using PVB Net Structure
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Solution Overview
Problem
Existing temperature-sensitive compositions for monitoring refrigerated or frozen products are prone to sensitivity loss over time, have a pasty appearance, and low encapsulation yield, making them costly and ineffective for long-term use.
Innovation Solution
A magnetizable chemical composition comprising a polar solvent, ferromagnetic particles, and a polymeric component like PVB or PVB-vinyl alcohol-vinyl acetate copolymer, which forms a net structure to stabilize and uniformly distribute particles, maintaining sensitivity and stability over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVP or polystyrene copolymer is used to stabilize magnetite nanoparticles, then the composition can be formed, but sensitivity decreases significantly over time due to particle agglomeration
Solution Approach 1:
The patent changes the chemical parameter of the stabilizing polymer from PVP/polystyrene copolymer to polyvinyl butyral (PVB), which fundamentally alters the stabilization mechanism. PVB maintains nanoparticle dispersion through different chemical interactions that prevent agglomeration over time, thus maintaining sensitivity stability throughout the product shelf-life without the degradation seen with PVP-based systems.
Solution Approach 2:
The patent creates a composite system combining PVB polymer with magnetite nanoparticles and fatty alcohol. This composite material provides synergistic effects where PVB stabilizes the magnetic particles while fatty alcohol provides additional surface coverage and prevents particle-particle interactions that lead to agglomeration, ensuring long-term sensitivity stability.
2Stability of the object's composition
If the composition has high polymer content to stabilize particles, then particle distribution improves, but the material becomes pasty and difficult to emulsify
Solution Approach 1:
The patent changes the polymer type from high-viscosity PVP to PVB, which has different rheological properties. PVB provides effective particle stabilization at lower concentrations, maintaining fluidity and emulsifiability. The molecular structure of PVB allows for adequate steric stabilization without forming the dense network that causes pasty consistency in PVP-based systems.
Solution Approach 2:
The patent applies different functional components in specific proportions: PVB for particle stabilization, fatty alcohol for surface activity and fluidity maintenance, and water as continuous phase. This localized functional assignment ensures that each component performs its specific role optimally without interfering with the overall emulsification process.
3Productivity
If water and PVP are used together, then the composition can be formed, but encapsulation yield is low due to water-PVP affinity
Solution Approach 1:
The patent changes the polymer from PVP to PVB, which has different hydrophilicity characteristics. PVB's hydrophobic nature reduces unwanted interactions with water during encapsulation, allowing for more efficient incorporation of the magnetic composition into capsules or matrices without significant material loss to the aqueous phase.
4Measurement precision
If thermochromic labels are used for temperature monitoring, then temperature threshold detection is achieved, but they are costly, disposable, and cannot provide time interval information
Solution Approach 1:
The patent replaces the thermochromic chemical system with a magnetic system. Instead of relying on color-changing dyes that require disposal, the invention uses magnetite nanoparticles whose magnetic properties change with temperature. This allows for reversible, reusable monitoring where the same sensor can be magnetized, read, reset, and used again, eliminating the need for disposable labels.
Solution Approach 2:
The magnetic composition inherently provides both temperature detection and time information through its magnetic relaxation properties. The composition self-registers temperature exposure history through progressive demagnetization, eliminating the need for external power sources, electronics, or replacement mechanisms that would add system complexity.
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 composition provides a stable, non-pasty, and highly emulsifiable solution for monitoring temperature variations, ensuring accurate detection of temperature excursions and extended shelf-life of products by maintaining sensitivity and stability, even after long-term storage.
Implementation Method 1
a ferromagnetic component, including a plurality of magnetizable particles of Stable Single Domain (SSD) type selected from the group comprising magnetite, substituted magnetite and/or ferrite
Implementation Method 2
measuring the residual magnetization of the composition, it thereby being possible to determine the maximum temperature reached
Implementation Method 3
the sensitivity, caused by the partial incapacity of the PVP network to stabilize the nanoparticles of magnetite, which after a certain time period are progressively agglomerated together and can no longer be demagnetized due to the Brownian mechanism
Implementation Method 4
a polymer component including PVB or PVB-vinyl alcohol-vinyl acetate copolymer in a percentage from 3 to 15% by volume of solvent, the polymeric component being shaped as a net or mesh and delimiting a plurality of housing cells or zones, in each of which one of the particles is housed
Implementation Method 5
By measuring the residual magnetization of the composition, it thereby being possible to determine the maximum temperature reached in the preserving zone of the product
Data Source
AI summary
A magnetizable chemical composition including at least one polar solvent (4) selected from the group comprising an alcohol with a number of carbon atoms from C8 to C14, polytetrahydrofuran, or a mixture thereof; a ferromagnetic component, including a plurality of magnetizable particles (1) of Stable Single Domain (SSD) type selected from the group comprising magnetite, substituted magnetite and/or ferrite in an amount from 5 to 15% by volume of solvent and having a diameter from about 20 nm to 50 nm; and a polymer component (2) including polyvinyl butyral (PVB) or polyvinyl butyral-vinyl alcohol-vinyl acetate copolymer in a percentage from 3 to 15% by volume of solvent, the polymeric component being shaped as a net or mesh and delimiting a plurality of housing cells or zones (3), in each of which one of said particles (1) is housed immersed in the polar solvent (4). A method of obtaining such a composition, a microcapsule comprising the composition, an ink comprising the microcapsules and a method of testing a product marked with such ink.