Polycarbonate Polyurethane Primer Layer for Eyeglass Lens Adhesion and Impact Resistance
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Solution Overview
Problem
Spectacle lenses with primer layers struggle to achieve excellent crazing resistance, impact resistance, and adhesion between the lens base and coating layers, particularly due to limitations in the properties of existing polyurethane resins and inorganic particles used in primer layers.
Innovation Solution
A spectacle lens with a primer layer composed of a polycarbonate polyurethane resin and inorganic oxide particles, where the resin has a tensile strength greater than 40 N/mm² and elongation of not less than 300%, and inorganic oxide particles constitute 10 to 40 vol% of the primer layer, enhancing adhesion and resistance properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a primer layer is formed using conventional polyurethane resins and inorganic particles, then adhesion between the lens base and coating layers is improved, but crazing resistance and impact resistance deteriorate
Solution Approach 1:
The patent changes the key parameter of the polyurethane resin by specifying a tensile strength greater than 40 N/mm² and elongation of not less than 300%. This parameter change transforms the resin from conventional weak formulations to a high-performance material that simultaneously provides adhesion and resistance to crazing and impact
Solution Approach 2:
The patent creates a composite primer layer by combining the high-tensile-strength polycarbonate polyurethane resin with inorganic oxide particles. This composite structure leverages the resin's toughness and the inorganic particles' hardness to achieve both adhesion and resistance properties
2Use of energy by moving object
If inorganic oxide particles are added to the primer layer to improve adhesion, then adhesion between layers is enhanced, but crazing resistance deteriorates
Solution Approach 1:
The patent formulates a composite primer layer containing both inorganic oxide particles and a high-tensile-strength polycarbonate polyurethane resin. The resin matrix with tensile strength >40 N/mm² and elongation ≥300% provides toughness that prevents crazing, while the inorganic oxide particles provide adhesion, resolving the contradiction between these two properties
Solution Approach 2:
The patent changes the mechanical parameters of the resin component in the composite to have exceptionally high tensile strength (>40 N/mm²) and elongation (≥300%). This parameter change ensures that the resin matrix can absorb stress and prevent craze formation even in the presence of inorganic oxide particles
Data Source
Figure 1~3
AI summary
This eyeglass lens is outstanding in anti-crazing properties, impact resistance properties, and adhesion. The present invention comprises: a lens substrate; a primer layer disposed on the lens substrate; and at least one layer that is disposed on the primer layer and that is selected from the group consisting of a hard-coat layer and a reflection-preventing layer. The primer layer contains a polycarbonate-based polyurethane resin and inorganic oxide particles. The tensile strength of the polycarbonate-based polyurethane resin is over 40 N/mm2. The expansion rate of the polycarbonate-based polyurethane resin is at least 300%, and the inorganic oxide particle content is 10-40% by volume with respect to the total volume of the primer layer.