Structured Adhesive Articles via Embossing Tool
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Solution Overview
Problem
Existing methods for forming microstructured laminating adhesive articles often introduce stresses during lamination, leading to defects in adhesive properties and optical quality due to the collapse of microstructured features, which can result in bubbles and pinholes in the bond line.
Innovation Solution
A method involving a multi-layer article construction with an embossing tool and a support surface tool, where the embossing tool imparts structures to both the liner and adhesive layer, allowing the structures to distort and retain their shape upon pressure release, enabling air egress without immediate collapse, thus minimizing bond line defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If applied pressure is used to collapse the microstructured features during lamination, then air can escape from the bonding interface, but stresses are introduced into the adhesive that create defects and adversely affect adhesive and optical properties
Solution Approach 1:
The adhesive is pre-applied to a microstructured release liner, creating a stable microstructured surface before lamination. This preliminary structuring allows air egress pathways to be established in advance, eliminating the need for pressure-induced collapse during bonding and preventing stress-related defects.
Solution Approach 2:
A microstructured release liner serves as an intermediary carrier that temporarily holds the adhesive in a structured state. The liner's microstructure provides stable air egress pathways during lamination without transferring stress to the adhesive, and is subsequently removed to leave the adhesive bonded to the substrate.
2Object-affected harmful factors
If the adhesive surface is contacted to a structured tool or release liner to form a structured pattern, then air egress is enabled during lamination, but the structures may flatten out and create stresses in the adhesive
Solution Approach 1:
The adhesive is pre-applied to a microstructured release liner, creating a stable microstructured surface before lamination. This preliminary structuring allows air egress pathways to be established in advance, eliminating the need for pressure-induced collapse during bonding and preventing stress-related defects.
Solution Approach 2:
The microstructured pattern is copied from the release liner to the adhesive surface through direct contact and curing. This copying process creates a stable, permanent microstructure in the adhesive that maintains its shape without requiring pressure-induced collapse, thereby preventing stress-related defects.
3Reliability
If the microstructured features are allowed to remain stable without collapse, then adhesive and optical properties are maintained, but air egress pathways may be insufficient during lamination
Solution Approach 1:
A microstructured release liner serves as an intermediary carrier that temporarily holds the adhesive in a structured state. The liner's microstructure provides stable air egress pathways during lamination without transferring stress to the adhesive, and is subsequently removed to leave the adhesive bonded to the substrate.
Solution Approach 2:
The adhesive is applied in a flowable state to the microstructured release liner, allowing it to conform to the microstructure. After curing, the adhesive maintains this structured form with stable air egress pathways, enabling air to escape during lamination without requiring pressure-induced collapse.
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 reduces stress in the adhesive layer, allowing for stable air egress and improved adhesive and optical properties by preventing bubble formation and enhancing the structural integrity of the bond line.
Implementation Method 1
applying pressure or a combination of pressure and heat to the construction such that at least some of the structures on the surface of the embossing tool distort the liner and the adhesive layer. The distortion in the liner is retained upon release of the applied pressure.
Implementation Method 2
the microstructured features created in the adhesive surface allow air to escape from the bonding interface, thereby minimizing or preventing the formation of bubbles and pinholes.
Implementation Method 3
applying pressure or a combination of pressure and heat to the construction such that at least some of the structures on the surface of the embossing tool distort the liner and the adhesive layer.
Data Source
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AI summary
Methods of forming laminating adhesive articles include providing a multi-layer article, an embossing tool with a structured surface, and a support surface tool. The multi-layer articles include a substrate, an adhesive layer, and a liner or may just include an adhesive layer and a liner. The multi-layer article is placed between the structured surface of the embossing tool and the support surface tool. The embossing tool is pressed against the liner and the support surface tool is simultaneously pressed against the substrate by applying pressure or a combination of pressure and heat. The pressing causes the structures on the surface of the embossing tool to distort the liner and the adhesive layer and the support surface tool modifies the surface of the substrate. The distortion in the liner is retained upon release of the applied pressure. Upon removal of the liner from the adhesive layer, the structures on the adhesive layer are unstable, but do not immediately collapse.