Ionizing Radiation Bonding of Substrates via Phosphor Down-Conversion
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Solution Overview
Problem
Conventional adhesives require direct line-of-sight access to light sources or thermal activation, which limits their efficiency and can cause thermal expansion mismatches when bonding dissimilar materials, and they often necessitate additional steps and tools, increasing cycle time and complexity in manufacturing.
Innovation Solution
Development of novel reactive chemistries that form free radicals under X-Ray energy, alone or in combination with UV radiation and heat, allowing for bonding of substrates without line-of-sight access or thermal heating, using down-converting energy converters like phosphors to generate reactive moieties for direct interface bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional photoinitiators are used for adhesive bonding, then polymerization can be initiated by light, but direct line-of-sight access to the light source is required which limits application flexibility
Solution Approach 1:
The patent introduces an intermediary substance (phosphor or scintillator material) that absorbs ionizing radiation and converts it to light, enabling photopolymerization without direct line-of-sight to the radiation source. This mediator allows the adhesive to cure through opaque or thick substrates that would block direct light access.
Solution Approach 2:
The patent replaces the conventional light-based activation system with an ionizing radiation-based system. Instead of using UV or visible light that requires direct line-of-sight, the system uses ionizing radiation (X-rays or gamma rays) that can penetrate substrates, combined with phosphor materials that convert the radiation energy into light for photopolymerization initiation.
2Productivity
If thermal activation is used for adhesive curing, then polymerization can occur, but the poor thermal conductivity of materials results in long process times
Solution Approach 1:
The patent replaces thermal activation with ionizing radiation activation. Instead of heating the adhesive and substrates to initiate polymerization (which is limited by thermal conductivity), the system uses ionizing radiation to directly activate phosphor materials that generate light, which then initiates rapid photopolymerization at ambient or reduced temperatures, dramatically reducing process time.
3Strength
If thermal heating is applied for adhesive curing, then polymerization is achieved, but thermal expansion mismatch occurs when bonding dissimilar materials
Solution Approach 1:
The patent changes the activation parameter from thermal energy to ionizing radiation energy. By using radiation-induced phosphor activation instead of thermal heating, the process can achieve strong adhesive bonds without subjecting dissimilar materials to thermal stress, thereby avoiding thermal expansion mismatch problems that occur when materials with different expansion coefficients are bonded together.
4Strength
If conventional adhesive processes are used, then bonding is achieved, but additional tools and process steps are required increasing cycle time
Solution Approach 1:
The patent merges multiple process steps into a single integrated operation. The adhesive application, positioning, and curing steps are combined into one process where the adhesive is applied and immediately cured by exposing the assembly to ionizing radiation, eliminating the need for separate heating equipment and extended curing cycles required by conventional thermal processes.
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
Enables efficient bonding of substrates at ambient temperature without the need for thermal heating, reducing cycle time and tool utilization, while minimizing thermal expansion issues and eliminating the requirement for an additional adhesive layer, thus streamlining manufacturing processes.
Implementation Method 1
the reactive chemistries react by way of a mechanism including, but not limited to, chain scission, photo-initiation, and a combination of chain scission and photo-initiation
Implementation Method 2
one or more down-converting energy converters, such as a phosphor or scintillator material
Implementation Method 3
photo-initiation, and a combination of chain scission and photo-initiation
Data Source
Figure 1~2
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AI summary
A reactive polymer composition is provided, containing a (co)polymer that forms one or more reactive moities, either directly or indirectly, upon application of an ionizing radiation; and a multifunctional curing coagent, along with systems and methods for bonding substrates to one another using such a composition. The present invention relates to the activation of suitably reactive chemistries across an interface after initiating a chemical reaction using a deeply penetrating form of ionizing energy including x-rays, gamma radiation, and e-beam.