Radiation-Cured Sealant for Uneven Automotive Surfaces
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Solution Overview
Problem
Conventional automotive sealants used in vehicle roof ditches are prone to deformation due to uneven substrate surfaces and external forces, leading to blow-through and compromised sealing effectiveness, while less deformable sealants fail to effectively seal the substrate.
Innovation Solution
A sealant article with a deformable composition that can be partially cured by radiation, creating a stable, non-deformable surface for external resistance while maintaining deformability for substrate conformance, using a thermoplastic composition with (meth)acrylate-functionalized monomers, thermally activatable initiators, and fillers, allowing for controlled flow and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft and flexible sealant composition is used to conform to uneven substrate surfaces, then the sealant can effectively seal the substrate, but the outer surface becomes highly susceptible to deformation due to trapped air, irregularities, or external forces
Solution Approach 1:
The sealant composition is segmented into two distinct surfaces with different properties: a first surface that remains soft and deformable for conforming to the substrate, and a second surface that is radiation-cured to be rigid and resistant to deformation. This segmentation allows each surface to independently fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the sealant article are given different mechanical properties. The first surface maintains high deformability locally to conform to substrate imperfections, while the second surface is locally cured to provide a rigid, deformation-resistant exterior. This local differentiation of material properties resolves the contradiction between needing softness for sealing and rigidity for surface stability.
2Shape
If a less easily deformable sealant composition is used to resist deformation, then the outer surface maintains its shape, but the ability to effectively seal the substrate surface is interfered with
Solution Approach 1:
The sealant is divided into two functional surfaces: a first surface that remains uncured and soft to effectively conform to and seal the substrate, and a second surface that is radiation-cured to provide shape stability. This segmentation allows the sealant to simultaneously achieve both surface stability and effective sealing without compromise.
Solution Approach 2:
The physical and chemical parameters of the sealant composition are changed selectively across different surfaces. The second surface undergoes radiation curing that fundamentally changes its parameter of deformability from high to low, while the first surface maintains its original high deformability parameter. This parameter differentiation enables the sealant to exhibit both rigidity and flexibility in the same article.
3Shape
If the entire sealant composition is radiation cured to provide a deformation-resistant surface, then the outer surface becomes stable, but the ability to conform to the substrate surface is lost
Solution Approach 1:
The radiation curing process is segmented to affect only the second surface of the sealant article, leaving the first surface uncured and soft. This selective segmentation of the curing process allows the sealant to achieve surface stability where needed while preserving substrate conformance capability where required.
Solution Approach 2:
Instead of applying radiation curing to the entire sealant composition, the action is applied partially to only the second surface. This partial action is sufficient to achieve the desired surface stability for the exterior while avoiding excessive curing that would compromise the conformability of the first surface to the substrate.
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 sealant article provides a durable, aesthetically pleasing seal that resists deformation and effectively covers substrate imperfections, ensuring a reliable and cosmetically acceptable seal on uneven surfaces.
Implementation Method 1
The second surface of the sealant article has been at least partially cured by exposing the surface to an amount of radiation effective to induce at least partial curing of the second surface
Implementation Method 2
at least one thermally activatable free radical initiator
Data Source
AI summary
A sealant article useful for sealing a substrate surface having a first surface and a second surface is provided. The first surface comprises a deformable composition that is capable of conforming to a substrate surface when subjected to heat and/or pressure. The second surface of the sealant article has been at least partially cured by exposing said surface to an amount of radiation effective to induce at least partial curing of the second surface of the sealant article. Prior to such curing, the second surface also is comprised of the deformable composition. Such at least partial curing is effective to render the second surface less deformable than the first surface.