Adhesive Tape Composition Using Frontal Cationic Polymerization
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Solution Overview
Problem
Existing adhesive and molding compositions require full-surface activation for polymerization, which is cumbersome and time-consuming, especially for large areas, and suffer from limited thickness, low adhesive strength, and poor storage stability due to radical curing systems.
Innovation Solution
A method using cationically polymerizable monomers with thermal or combined cationic/thermal initiators for frontal polymerization, allowing activation at a single location with thermal or radiation energy, eliminating the need for full-surface activation and enabling rapid polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymerization methods are used with full-surface activation, then complete curing of the adhesive mass is achieved, but the process becomes cumbersome and time-consuming
Solution Approach 1:
The patent introduces a localized initiator system where thermal or photo initiators are concentrated at the interface between the adhesive mass and the substrate. This creates a localized polymerization front that propagates through the adhesive layer, eliminating the need for full-surface activation while ensuring complete curing. The localized initiation simplifies the application process by requiring only contact with the substrate rather than external activation of the entire surface.
Solution Approach 2:
The adhesive composition is pre-formulated with embedded thermal or photo initiators and polymerizable monomers in a stable, non-cured state. This preliminary preparation allows the adhesive to be applied in its uncured form, maintaining ease of application, and then cured in situ through contact with the substrate or localized energy input, achieving complete curing without cumbersome post-application activation procedures.
2Reliability
If two-component polymerization systems are used, then curable composition is achieved, but pot life is limited to a short time
Solution Approach 1:
The patent segments the curing system into three components: polymerizable monomers, thermal or photo initiators, and inert fillers or modifiers. This segmentation allows the composition to remain stable during storage and application, with curing only initiated when thermal or photo energy is applied to the interface. This eliminates the short pot life problem of two-component systems while maintaining complete curability.
Solution Approach 2:
The patent changes the activation parameter from chemical mixing (two-component systems) to physical energy input (thermal or photo). By using thermally or photo-initiated polymerization of pre-formulated compositions, the system maintains stability during storage and application, with curing triggered by energy input rather than chemical reaction upon mixing. This extends the usable time significantly while ensuring complete curing.
3Reliability
If conventional activation methods are used, then polymerization is induced, but equipment complexity increases
Solution Approach 1:
The adhesive mass contains embedded thermal or photo initiators that enable self-curing when exposed to appropriate energy. For thermal initiation, the exothermic polymerization reaction itself provides the heat needed to propagate the reaction front. For photo initiation, ambient or simple UV light sources suffice. This eliminates the need for complex external activation equipment, achieving reliable polymerization induction through the material's own properties.
Solution Approach 2:
The patent replaces complex mechanical or chemical activation systems with simpler thermal or photo initiation mechanisms. Instead of requiring complex two-component mixing systems or elaborate activation equipment, the invention uses thermally or photo-initiated polymerization of pre-formulated compositions, which can be activated by simple heat application or ambient UV light, significantly reducing equipment complexity while ensuring reliable curing.
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
Facilitates rapid and efficient polymerization of adhesive tapes and molding masses without complex equipment, allowing bonding of large areas and complex shapes with high adhesive strength and improved storage stability.
Implementation Method 1
a thermal cationic initiator, or B) a combination of a cationic photoinitiator and a thermal free-radical initiator for inducing the polymerization of the cationically polymerizable monomers
Implementation Method 2
a combination of a cationic photoinitiator and a thermal free-radical initiator for inducing the polymerization of the cationically polymerizable monomers
Implementation Method 3
the heat energy released during polymerization is sufficient for causing cleavage of the thermal initiator
Data Source
AI summary
A polymerizable composition which may be used as an adhesive mass in a method for preparing an adhesive tape or as molding mass in a method for preparing molded articles is provided. The polymerizable composition contains: A) a thermal cationic initiator, or B) a combination of a cationic photoinitiator and a thermal free-radical initiator for inducing the polymerization of the cationically polymerizable monomers in such an amount that the heat energy released during polymerization is sufficient for cleaving the thermal initiator. The adhesive mass is curable via a local impulse a) of thermal energy orb) of thermal energy and/or radiation energy through frontal polymerization; or the molding mass is initially prepared by mixing all components and then molded into the desired shape, whereafter its frontal polymerization is induced by a local impulse a) of thermal energy and/or b) of radiation energy in order to prepare a cured molded article.