Optical Article Antifog Coating Edging via Silica Temporary Layer
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Solution Overview
Problem
Optical articles with hydrophobic and/or oleophobic coatings present challenges during edging due to poor adhesion, leading to slipping and offsetting issues, and existing solutions for antifog coatings with excess precursor layers are not industrially viable due to complex cleaning requirements and handling difficulties.
Innovation Solution
A temporary layer with at least 50% silica by weight is applied between the precursor antifog coating and the fixing device, allowing for effective edging by improving adhesion and being easily removable post-processing, while maintaining antifog properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydrophobic and/or oleophobic coating is applied to the optical article, then dirt-repellent and antifog properties are improved, but adhesion during edging deteriorates causing slipping and offsetting
Solution Approach 1:
A temporary layer comprising at least 50% silica by weight is introduced as an intermediary between the hydrophobic/oleophobic coating and the fixing device during edging. This temporary layer provides the necessary adhesion for stable fixing during the edging operation, while being easily removable afterward to preserve the antifog properties of the underlying coating.
2Reliability
If a precursor coating for antifog is deposited in excess, then antifog properties are improved, but manufacturing complexity increases due to cleaning requirements
Solution Approach 1:
The temporary silica-based layer serves as a mediator that simplifies the overall process. Instead of requiring complex cleaning procedures to remove excess precursor coating, the temporary layer is deposited over the precursor coating and provides a stable surface for edging. After edging, the temporary layer is easily removed, leaving the precursor coating intact for antifog functionality.
Solution Approach 2:
The temporary layer acts as a disposable intermediary that is deposited, used for the edging operation, and then easily removed. This approach avoids the need for complex cleaning processes to remove excess precursor coating, as the temporary layer is designed to be simply removed after serving its purpose during edging.
3Ease of operation
If a temporary layer is applied for edging, then adhesion and ease of edging are improved, but an additional processing step is required for removal
Solution Approach 1:
The temporary layer is designed as a disposable intermediary that is easily deposited and easily removed. Although it adds a processing step, the simplicity of its removal (compared to removing excess precursor coating) makes it a practical solution for enabling stable edging operations on hydrophobic/oleophobic coatings.
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 temporary silica-based layer ensures reliable edging operations with minimal offsetting and easy removal, preserving the antifog properties of the optical articles without affecting their transparency or durability.
Implementation Method 1
A temporary layer with at least 50% silica by weight is applied between the precursor antifog coating and the fixing device, allowing for effective edging by improving adhesion
Implementation Method 2
a group capable of establishing a covalent bond with a silanol group
Implementation Method 3
by grafting an organosilane compound having a polyoxyalkylene group and at least one silicon atom carrying at least one hydrolyzable group
Implementation Method 4
These permanent antifog coatings, the hydrophilic properties of which result from hydrophilic compounds permanently bonded to another coating or support, act as sponges with regard to the fogging and make it possible for the water droplets to adhere to the surface of the support by forming a very thin film
Implementation Method 5
an external part, which can be removed by washing and/or wiping, resulting from the deposition of the compound A
Data Source
AI summary
The present invention concerns an optical article comprising a substrate, at least one of the main surfaces of which is coated with a first coating comprising, at its surface, silanol groups and, in direct contact with this coating, a second coating which is a precursor for an antifog coating, the second coating being formed by deposition, on the first coating, of at least one compound A having a polyoxyalkylene group, and at least one group capable of establishing a covalent bond with a silanol group, wherein the second coating comprises an internal part, in which compound A is grafted to the first coating, and an external part, which can be removed by washing and/or wiping, resulting from the deposition of the compound A, and wherein the second coating is coated with at least one temporary layer comprising at least 50% by weight of silica.