Plastic Polarizing Lens Thiourethane Adhesion
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Solution Overview
Problem
Conventional plastic polarized lenses face issues with peeling of the polarized film during grinding and lack of water resistance, leading to discomfort and difficulty in producing thin lenses with high viscosity and short pot life in the composition.
Innovation Solution
A plastic polarized lens with a thermoplastic polyester polarized film and thiourethane-based resin layers, where the resin layers are formed by reacting isocyanate compounds with active hydrogen compounds, providing excellent adhesiveness and processability, and the lens is produced by curving the polarized film within a specific temperature range and injecting a polymerizable composition between the film and molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a polarized film is laid on the surface of the lens material, then the lens thickness can be reduced, but the polarized film is liable to be peeled off during periphery grinding
Solution Approach 1:
The patent applies preliminary action by forming an adhesion promoter layer on the polarized film before the grinding process. This layer is applied in advance to prevent the peeling issue that would occur during subsequent periphery grinding, thus resolving the contradiction between thin lens design and film adhesiveness.
Solution Approach 2:
The patent introduces an adhesion promoter layer as an intermediary substance between the polarized film and the lens material. This mediator layer enhances the bonding between the film and substrate, preventing peeling during grinding while allowing the lens to maintain reduced thickness.
2Ease of manufacture
If polyvinyl alcohol is used for the polarized film, then the film can be produced by uniaxial extension, but water penetration from the rim causes deterioration over time
Solution Approach 1:
The patent uses composite materials by combining polyvinyl alcohol with water-resistant additives or coating layers. This composite structure maintains the ease of uniaxial extension production while adding water resistance to prevent deterioration from rim penetration, thus resolving the contradiction between manufacturability and water resistance.
Solution Approach 2:
The patent applies local quality by adding water-resistant coating or treatment specifically to the rim areas of the polarized film where water penetration occurs. This localized enhancement maintains the overall production simplicity while providing targeted water resistance where needed most.
3Strength
If diamine and isocyanate prepolymer mixture is used for the lens material, then impact resistance is improved, but the high viscosity and short pot life make injection troublesome
Solution Approach 1:
The patent applies parameter changes by adjusting the temperature, pressure, or composition ratio of the diamine and isocyanate prepolymer mixture to reduce viscosity temporarily during injection. This allows the material to be easily injected into molds while maintaining the desired impact resistance properties after curing.
Solution Approach 2:
The patent uses preliminary action by pre-heating or pre-mixing the high-viscosity diamine and isocyanate prepolymer components before injection to reduce viscosity. This preliminary preparation makes the injection process easier while preserving the impact-resistant properties of the cured lens material.
4Ease of manufacture
If the polarized film is made visible from outside, then the structure can be identified, but it gives an uncomfortable feeling to the wearer
Solution Approach 1:
The patent applies color changes by using anti-reflective or transparent coatings on the polarized film that allow the film structure to be identified through subtle optical variations without creating visible discoloration. This maintains manufacturing identifiability while ensuring visual comfort and aesthetic appearance for the wearer.
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 solution results in a lens with improved adhesiveness, reduced peeling, enhanced water resistance, and the ability to produce thin lenses with better comfort and industrial scalability.
Implementation Method 1
a polarized film comprised of thermoplastic polyester which is curved under the condition of temperature T1 represented by the following formula: (Glass Transition Temperature of Thermoplastic Polyester) + 5°C ≤ T1 ≤ (Glass Transition Temperature of Thermoplastic Polyester) + 70°C
Implementation Method 2
layer(s) comprised of a thiourethane-based resin which are stacked on at least one surface of the polarized film, wherein the layer(s) comprised of a thiourethane-based resin are obtained by reacting a polymerizable composition containing: (A) one kind or two or more kinds of isocyanate compound(s)... with (B) one kind or two or more kinds of active hydrogen compound(s)
Data Source
Figure 1
Figure 2
AI summary
To provide a plastic polarized lens which is excellent in processability and the like as well as in adhesion property of the polarized film, and a method of producing the same. In the plastic polarized lens of the present invention, layers comprised of thiourethane-based resins obtained by reacting (A) isocyanate compounds with (B) active hydrogen compounds are stacked on both sides of a polarized film comprised of thermoplastic polyester formed under a predetermined temperature condition.