Silicone Seal Bonding with PSA Tape and Structural Adhesive
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Solution Overview
Problem
The existing methods for fixing silicone seals to aircraft, trains, or motor vehicles using RTV silicone adhesive are inefficient due to long curing times, requiring significant storage space and reducing productivity, and struggle to achieve strong adhesive bonds between silicone surfaces and pressure-sensitive adhesive (PSA) tapes.
Innovation Solution
A process involving surface treatment of the silicone part to increase its surface energy, followed by application of a non-silicone-based structural adhesive and a double-sided adhesive tape with PSA layers, which enhances the peel strength of the adhesive bond by acting as a tie layer or primer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RTV silicone adhesive is used to bond silicone seals, then adhesive bonding is achieved, but curing time is very long (several hours to tens of hours) and productivity is reduced
Solution Approach 1:
The patent introduces an intermediate adhesive tape with PSA layer between the silicone seal and the final substrate. This intermediary enables instantaneous bonding while the structural adhesive cures slowly in the background, resolving the contradiction between reliable bonding and productivity by separating the immediate bonding function from the long-term structural function.
Solution Approach 2:
The adhesive tape with PSA layer is prepared in advance and applied to the silicone seal before the structural adhesive is applied. This preliminary action allows the seal to be immediately bonded and positioned, enabling continuous production while the structural adhesive cures over time.
2Reliability
If oxidizing surface treatment is applied to silicone surface, then surface energy is increased for better adhesion, but the effect is not stable over time and material becomes hydrophobic again
Solution Approach 1:
The surface treatment is applied in advance before adhesive application, maximizing the surface energy during the critical bonding phase. The adhesive is applied immediately after treatment while the surface is still highly reactive, ensuring strong bonding before hydrophobic recovery occurs.
Solution Approach 2:
The adhesive tape with PSA layer acts as an intermediary that bonds to the treated silicone surface during its high-energy state. The PSA formulation is selected to maximize bonding to the oxidized surface, creating a stable intermediate bond that persists even as the surface recovers hydrophobicity.
3Productivity
If adhesive tape with PSA is applied to silicone surface, then instantaneous bonding is achieved, but peel strength is insufficient
Solution Approach 1:
The patent merges two adhesive systems: the PSA layer for instantaneous bonding and the structural adhesive for long-term strength. The PSA provides immediate peel strength for productivity, while the structural adhesive cures over time to provide sustained high strength, combining the benefits of both adhesive types.
Solution Approach 2:
The adhesive system is composite, consisting of the PSA layer and structural adhesive layer working together. The PSA layer provides immediate adhesion and positioning, while the structural adhesive provides long-term structural strength, creating a composite adhesive system that achieves both instantaneous bonding and high peel strength.
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 process significantly increases the peel strength of the adhesive bond between the silicone part and the adhesive tape, achieving values up to ten times higher than without the PSA, allowing for instantaneous and strong bonding.
Implementation Method 1
treating at least one region of the surface of a silicone part so as to increase the surface energy of the region treated
Implementation Method 2
a first layer of a pressure-sensitive adhesive (PSA) on a first face of the support tape, intended to be brought into contact with the silicone part
Data Source
AI summary
An assemblage including a silicone part; and a double-sided adhesive tape including a support tape, a first layer of a pressure-sensitive adhesive (PSA) on a first face of the support tape, a second layer of a PSA on a second face of the support tape, and where the silicone part and the double-sided adhesive tape are adhesively bonded to one another using a non-silicone-based structural adhesive.