Retroreflective Traffic Signs with Adhesive Cell-Wall Air Gaps
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Solution Overview
Problem
Current methods for manufacturing retroreflective traffic signs involve combining separate components such as retroreflective sheeting and aluminum panels, which are costly and labor-intensive, requiring additional layers like protective backing, adhesive, and release liners.
Innovation Solution
A process and apparatus for directly laminating a polymeric retroreflective microprismatic thin film to an aluminum backing, eliminating the need for a protective backing layer, adhesive, and release liner, by using cell walls formed from adhesives to create an air gap between the microprismatic elements and the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional multi-layer reflective sheeting with backing layer, adhesive layer, and release liner is used, then the retroreflective sign can be manufactured and assembled, but the material cost and manufacturing complexity increase significantly
Solution Approach 1:
The patent removes the protective backing layer, adhesive layer, and release liner from the traditional multi-layer reflective sheeting structure. Only the essential retroreflective film with microprismatic elements is retained, eliminating unnecessary components while preserving the core retroreflective function.
Solution Approach 2:
The patent combines the retroreflective film directly with the substrate using a simplified single-sided adhesive application method. The adhesive is applied only to specific areas where bonding is needed, merging the bonding function into the manufacturing process rather than requiring separate adhesive layers and release liners.
2Strength
If traditional lamination process with release liner removal and separate adhesive application is used, then the retroreflective film can be bonded to the substrate, but the labor cost and production time increase
Solution Approach 1:
The adhesive is pre-applied to the substrate in the desired pattern before the retroreflective film is positioned and bonded. This preliminary adhesive application eliminates the need for subsequent adhesive application steps and release liner removal, streamlining the manufacturing process while ensuring proper bond strength.
Solution Approach 2:
A single-sided adhesive pattern serves as an intermediary between the retroreflective film and the substrate, providing sufficient bond strength while allowing for simplified handling and positioning during the manufacturing process. The adhesive pattern enables direct bonding without requiring complete surface coverage or complex lamination procedures.
3Strength
If complete surface adhesive coverage is used for bonding, then strong adhesion is achieved, but material cost and processing complexity increase
Solution Approach 1:
The adhesive is applied in a localized pattern rather than as a complete surface coverage. The adhesive pattern is concentrated in specific areas where bonding is required, providing sufficient adhesion strength while minimizing adhesive material consumption and simplifying the application process.
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 method reduces material and labor costs, enabling the production of fully functional traffic signs with reduced overall costs and simplified manufacturing processes, while maintaining retroreflective properties.
Implementation Method 1
a retroreflective film with retroreflective elements on one surface
Implementation Method 2
adhering the film directly to the substrate
Data Source
AI summary
A retroreflective sign comprising a rigid substrate with a pattern of cell walls formed of a polyurethane adhesive or two-part polyurea adhesive, and a polymeric sheet having a front face and a rear face, the rear face facing the substrate, the rear face comprising microprismatic reflective elements is disclosed. The polymeric sheet is adhered directly to the cell walls formed of the polyurethane adhesive or two-part polyurea adhesive while leaving an air gap between the microprismatic retroreflective elements and the rigid substrate in the cells. A method of making the retroreflective sign includes applying a polyurethane adhesive or two-part polyurea adhesive to a front side of a rigid substrate in a pattern defining cell walls; and prior to full curing of the polyurethane adhesive, laminating the front side of the rigid substrate a rear side of a polymeric sheet via the cell walls, the polymeric sheet comprising microprismatic elements.