Adhesion Primer for Cast Polymer Lenses
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Solution Overview
Problem
Current polarized ophthalmic lenses face issues with delamination during manufacturing and finishing processes due to inadequate adhesion between the polarizing film and the lens casting material, particularly with polyvinyl alcohol (PVA) films, which are fragile and prone to damage, and existing primers damage the optical quality of triacetyl cellulose (TAC) laminates while providing insufficient adhesion.
Innovation Solution
A primer composition comprising acrylic polymer, urethane acrylate oligomer, reactive monomer, and solvents is applied to the TAC-based polarizing laminate, allowing penetration into the TAC layer for enhanced adhesion, reacting with the casting monomer to form a strong bond, and is UV-cured for improved durability and resistance to aggressive surfacing and edging tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If current industrial primers are applied to TAC polarizing laminate, then adhesion is improved, but optical quality is damaged
Solution Approach 1:
The primer formulation uses specific parameter ranges: acrylic polymer (1-30%), urethane acrylate oligomer (1-30%), reactive monomer (0.5-15%), initiator (0.1-5.0%), and solvent (50-95%). These controlled parameters enable adequate adhesion while maintaining optical quality by preventing excessive primer penetration or reaction that would damage the TAC laminate
Solution Approach 2:
The primer is a composite material combining multiple components (acrylic polymer, urethane acrylate oligomer, reactive monomer, initiator, and solvent) that work synergistically. The acrylic polymer and urethane acrylate provide adhesion, the reactive monomer bonds to casting monomer, and the solvent controls penetration - together achieving both adhesion and optical quality without relying on a single aggressive component
2Ease of manufacture
If PVA polarizing films are used, then manufacturing cost is reduced, but handling durability is compromised
Solution Approach 1:
The PVA polarizing film is nested within protective TAC layers to form a TAC/PVA/TAC laminate structure. This nested configuration protects the fragile PVA film from damage during handling while maintaining manufacturing cost effectiveness, as the TAC layers serve as durable outer shells that withstand mechanical stress
Solution Approach 2:
Different layers of the laminate have different local qualities optimized for their specific functions: the TAC outer layers provide durability and handling strength, while the inner PVA layer provides polarizing functionality at low cost. This spatial differentiation of material properties resolves the contradiction between cost and durability
3Strength
If primer penetration into TAC layer is increased, then adhesion is improved, but optical quality may be compromised
Solution Approach 1:
The solvent acts as an intermediary that controls primer penetration into the TAC layer. It allows sufficient penetration for adequate adhesion bonding while being removable afterward, preventing permanent optical damage. The solvent mediates between the need for penetration (adhesion) and the need to preserve optical clarity
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 primer significantly reduces delamination risks during lens processing, enhancing production yields and productivity by providing robust adhesion that withstands mechanical stress and maintains optical quality.
Implementation Method 1
The primer reactive monomer may react with the casting monomer to provide a strong bond between the cast polymer and the polarizing laminate
Implementation Method 2
The primer is applied onto one or both sides of a polarizing laminate, dried, UV cured, then cast in a casting monomer formulation
Data Source
Figure 1~3
AI summary
Embodiments of the disclosure relate to a primer composition for increasing the adhesion of a polarizing film laminate to a cast-polymerized lens. The primer includes an acrylic polymer, polyurethane acrylate oligomer, a solvent, a UV curing agent, and a monomer which promotes adhesion to a cast-polymerized lens.