Silicone Release Layer E-Beam Crosslinking Adhesive Tape
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Solution Overview
Problem
The use of electron beam radiation to crosslink double-sided adhesive tapes can alter the release properties of silicone release layers, leading to unpredictable adhesion and 'liner confusion' or 'liner blocking', where the release liner cannot be removed, especially when the exposed surface is treated before winding into a roll.
Innovation Solution
A method involving a backing with opposing silicone release layers, one of which is partially cured and hydrosilation-crosslinkable, with a specific molar ratio of Si—H to vinyl groups, allowing for crosslinking of the adhesive layer while maintaining controlled release properties, even after electron beam exposure in the presence of oxygen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If electron beam radiation is used to crosslink the adhesive layer, then crosslinking effectiveness is improved, but the release properties of the silicone release layer are altered in a deleterious fashion
Solution Approach 1:
The patent changes the chemical composition parameters of the silicone release layer by incorporating specific additives (extractables) that modify how the layer responds to electron beam radiation. This allows the adhesive to be crosslinked effectively while the release layer maintains its release properties despite exposure to E-Beam radiation.
Solution Approach 2:
The silicone release layer acts as an intermediary between the electron beam radiation and the adhesive layer. By carefully formulating the release layer with specific extractables, it mediates the radiation exposure to protect the release properties while still allowing the adhesive to be crosslinked underneath.
2Strength
If the exposed surface of the silicone release layer is exposed to E-Beam radiation before winding into a roll, then the adhesive bond increases over time, but this leads to liner confusion and liner blocking
Solution Approach 1:
The patent modifies the chemical parameters of the silicone release layer by adding specific extractables that change its reactivity to electron beam radiation. This ensures that even after E-Beam exposure, the release layer maintains sufficient release properties to allow easy liner removal, preventing liner confusion and blocking.
Solution Approach 2:
The release layer is pre-formulated with extractables that provide preliminary protection against the harmful effects of electron beam radiation. This preliminary anti-action prevents the radiation from creating excessive adhesive bonds between the liner and adhesive, thereby preventing future liner blocking issues.
3Reliability
If a temporary release liner is used and replaced after crosslinking, then E-Beam treatment problems are avoided, but process complexity and cost increase
Solution Approach 1:
The silicone release layer is designed to serve multiple functions simultaneously: it provides release properties, withstands electron beam radiation exposure, and maintains its integrity throughout the manufacturing process. This multi-functionality eliminates the need for separate temporary liners and replacement steps, simplifying the overall process.
Solution Approach 2:
The release layer is self-sufficient in handling the electron beam radiation exposure. By incorporating the right extractables, it automatically protects itself and the adhesive system during crosslinking, eliminating the need for external intervention through temporary liners or process modifications.
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
This approach ensures that the second silicone release layer releases from the adhesive layer before the first, maintaining differential release forces and preventing liner blocking, thus stabilizing the adhesion properties and simplifying the production process without the need for a temporary release liner.
Implementation Method 1
exposing at least the adhesive layer to electron beam radiation within a process chamber thereby providing a crosslinked adhesive layer
Implementation Method 2
the process chamber contains oxygen, wherein the second silicone release layer is exposed to the oxygen during crosslinking of the adhesive layer
Implementation Method 3
the silicone release layer comprises a partially cured hydrosilation-crosslinkable silicone mixture
Data Source
AI summary
A method of making an adhesive article comprises three steps. First, the method includes providing a liner having first and second opposed major surfaces with respective first and second silicone release layers disposed thereon. The second silicone release layer comprises a partially cured hydrosilation-crosslinkable silicone mixture comprises a first silicone polymer having at least three Si—H groups and second silicone polymer have at least two vinyl, and has an extractables content of 5 to 25 weight percent. Second, an adhesive layer is disposed onto the first silicone release layer. Third, the adhesive layer is exposed to E-beam radiation within a process chamber thereby providing a crosslinked adhesive layer. The second silicone release layer is exposed to oxygen during crosslinking of the adhesive layer. Adhesive articles made according to the method also disclosed.