AlNiCo Magnetic Particle Shells for Secure Infrared-Reflective Ink
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Solution Overview
Problem
Conventional magnetic particles face challenges in achieving uniform composition and size, leading to difficulties in distinguishing them from paramagnetic particles using high-priced recognition equipment, and they struggle with printability and infrared reflectivity, which compromises security features in security materials.
Innovation Solution
AlNiCo-based magnetic particles with a core particle composition of Al, Ni, and Co, coated with an inorganic shell, produced using a water-based atomization process to ensure uniformity and a specific particle size distribution, achieving coercivity, saturation magnetization, and infrared reflectance for enhanced security features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic particles have high magnetization density, then security is improved, but it becomes difficult to measure a unique signal by high-priced recognition equipment
Solution Approach 1:
The patent optimizes the magnetization density parameter to a specific range (0.3-1.5 emu/g) that balances security requirements with detectability by recognition equipment. This parameter change resolves the contradiction by finding the optimal value that satisfies both security and measurement needs
2Ease of manufacture
If magnetic particles have large size, then it is easier to produce, but they cannot effectively reflect sunlight to conceal original dark colored particles
Solution Approach 1:
The patent specifies an optimal particle size range (3-15 μm) that balances manufacturability with sunlight reflection capability. This parameter optimization resolves the contradiction by identifying the size range where both production ease and optical concealment are satisfied
3Reliability
If coercivity of magnetic particles is too high, then security is improved, but it becomes difficult to form uniform composition and size
Solution Approach 1:
The patent optimizes coercivity to a specific range (50-200 Oe) that maintains security while enabling uniform composition and size formation. This parameter optimization resolves the contradiction by finding the coercivity range where both security and manufacturing precision are achieved
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 AlNiCo-based magnetic particles provide improved security by ensuring uniform magnetic properties, enhanced printability, and high infrared reflectivity, making them distinguishable only by high-priced recognition equipment and effectively concealing dark colors, thus improving the security of security materials.
Implementation Method 1
an atomization process is known as a method of producing magnetic particles having a certain size. The atomization process is classified into a gas atomization process, a water atomization process, and a mixed spraying process, depending on the kind of cooling media. Generally, in the atomization process, a molten alloy is sprayed into a cooling medium through a nozzle to allow a molten alloyalloy and the cooling medium to collide with each other to cool the droplets of the molten alloy
Implementation Method 2
in the water atomization process, water (H 2 O) is used as a main cooling medium
Implementation Method 3
The AlNiCo-based magnetic particles provide improved security by ensuring uniform magnetic properties, enhanced printability, and high infrared reflectivity
Implementation Method 4
when ferromagnetic particles having a relatively large coercivity and soft-magnetic particles having a relatively small coercivity are mixed and formed into a certain shape or pattern
Data Source
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AI summary
AlNiCo-based magnetic particles according to the present invention are hard magnetic particles each comprising: a core particle containing Al, Ni, and Co; and an inorganic shell enclosing the core particle, wherein the core particle is an ultra-fine particle having D50 of smaller than 12 µm, D50 being particle size corresponding to 50% in the core particle diameter cumulative distribution, and wherein the core particle has a composition uniformity of equation 1, equation 2, and equation 3 below: 10≤UNFAl 10≤UNFNi 10≤UNFCo In equation 1, UNF (Al) is the value obtained by dividing the average Al composition among core particles by the standard deviation of the Al composition on the basis of weight% of the composition. In equation 2, UNF (Ni) is the value obtained by dividing the average Ni composition among core particles by the standard deviation of the Ni composition on the basis of weight% of the composition. In equation 3, UNF (Co) is the value obtained by dividing the average Co composition among core particles by the standard deviation of the Co composition on the basis of weight% of the composition.