Polyamide Film Primer Layer Adhesion
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Solution Overview
Problem
Polyamide-based films used as cover windows for flexible display devices face challenges in securing adhesiveness with functional layers such as hard coating and optically clear adhesive layers, lacking sufficient adhesive strength and optical/mechanical properties.
Innovation Solution
A multilayer film comprising a polyamide-based base layer with a primer layer containing 60% to 95% polyester-based resin, enhancing adhesive strength and optical/mechanical properties by improving surface energy and adhesion with functional layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyamide-based film is used as a cover window without surface treatment or with conventional primer treatment, then the film maintains its transparency and flexibility, but the adhesive strength with functional layers such as hard coating and OCA layers is insufficient
Solution Approach 1:
The patent applies preliminary action by introducing a primer layer before the functional layers are applied. This primer layer is specifically designed to enhance adhesion between the polyamide-based base layer and subsequent functional layers (hard coating, OCA layer, etc.). The primer layer is applied in advance to prepare the surface for better bonding, thereby resolving the adhesive strength issue without requiring complex surface treatments.
Solution Approach 2:
The patent uses an intermediary approach by inserting a primer layer between the polyamide-based base layer and the functional layers. This primer layer acts as a mediator that improves interfacial adhesion. The primer layer contains specific components (such as polyester-based resin, acrylic-based resin, or urethane-based resin) that are compatible with both the base layer and the functional layers, facilitating strong bonding while maintaining simplicity.
2Strength
If surface treatment is applied to improve adhesion, then adhesive strength with functional layers is improved, but the optical and mechanical properties may be compromised
Solution Approach 1:
The patent applies parameter changes by carefully controlling the composition and properties of the primer layer. The primer layer is formulated with specific resin types (polyester-based, acrylic-based, or urethane-based) and weight ratios to optimize both adhesion and optical/mechanical properties. By adjusting these parameters, the primer layer achieves strong bonding while maintaining the transparency and flexibility of the underlying polyamide-based film.
Solution Approach 2:
The patent employs composite materials by combining multiple resin components in the primer layer (e.g., polyester-based resin, acrylic-based resin, and urethane-based resin in specific ratios). This composite approach allows the primer layer to simultaneously provide adhesion enhancement and preserve optical/mechanical properties. The synergistic effect of different resins ensures both strong bonding and maintained film properties.
Data Source
AI summary
In the multilayer film provided with a primer layer of a specific composition comprising a polyester-based resin on a polyamide-based base layer, the adhesive strength with a hard coating layer and an OCA layer to be coated on the surface thereof is excellent, as well as the optical and mechanical properties are also excellent.