Mold-Surface Catalysis for Fast Room-Temperature Lens Curing
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Solution Overview
Problem
Existing methods for manufacturing transparent plastic substrates for optical articles like ophthalmic lenses require thermal activation, which is complex and environmentally unfriendly, and the shelf life of fast room-temperature polymerizable compositions is limited, necessitating rapid mixing and filling to avoid premature gelation.
Innovation Solution
A method involving a fast room-temperature polymerizable composition is used, where a catalyst composition is deposited on the inside surfaces of molds or a light filtering element, forming a mold assembly, and the composition is filled into the cavity to polymerize at room temperature, followed by a post-curing step to form a transparent solid substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a catalyst solution is added to monomers or prepolymers to enable fast room-temperature polymerization, then the polymerization speed is improved, but the shelf life of the composition decreases due to premature gelation
Solution Approach 1:
The system is divided into separate components: a polymerizable composition and a catalyst composition, which are kept apart during storage. The catalyst is deposited on the mold surface rather than being mixed with the monomers, allowing the composition to be stored for extended periods without premature polymerization. When ready for use, the catalyst is activated by contact with the polymerizable composition at the mold interface, enabling fast polymerization only where needed.
2Reliability
If thermal activation is used for polymerization, then the polymerization process is reliable, but the manufacturing complexity increases and environmental friendliness decreases
Solution Approach 1:
The patent replaces thermal activation (mechanical/thermal system) with a chemical catalysis system operating at room temperature. The catalyst composition, when contacted with the polymerizable composition on the mold surface, triggers polymerization without requiring external heating equipment or thermal control systems, thereby simplifying the manufacturing process while maintaining reliability.
3Reliability
If the remaining monomer or prepolymer is added quickly after catalyst addition, then premature gelation is avoided, but the manufacturing process complexity increases
Solution Approach 1:
The catalyst is pre-deposited on the mold surface in a stable form before the polymerizable composition is applied. This preliminary positioning of the catalyst eliminates the need for rapid mixing and filling operations, as the catalyst and monomers remain separate during storage and handling. The polymerization is initiated only when the composition contacts the catalyst-coated mold, allowing for extended preparation time without compromising stability.
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 simplifies manufacturing by avoiding thermal activation, extends the shelf life of the composition, and produces defect-free transparent substrates without convection or filling-induced striations, suitable for optical articles.
Implementation Method 1
a first step for polymerizing said composition at room temperature to obtain a gel
Implementation Method 2
polymerization of a polymerizable composition comprising monomer and/or oligomer which are able to polymerize under thermal activation to form a polymer
Data Source
AI summary
The present application relates to a method of fast curing transparent casted substrate, usable for making optical articles such as ophthalmic lenses, which comprises the steps of:—providing a fast room-temperature polymerizable composition:—providing a catalyst composition;—providing a casting mold assembly containing two unsealed molds each having an inside surface and an outside surface; and optionally providing a light filtering element placed or configured to be placed between the two molds—depositing the catalyst composition:—on the inside surfaces of at least one of the molds; and/or—on at least one of the surfaces of the light filtering element which is thereafter positioned in the mold assembly;—closing the casting mold assembly so that the inside surfaces of the molds form together the molding cavity:—filling the fast room-temperature polymerizable composition in the molding cavity of the casting mold assembly already containing the catalyst composition deposited on the inside surface of at least one of the molds:—curing the filled mold assembly to obtain a transparent solid substrate, said curing step comprising: a) a first step for polymerizing said composition at room temperature to obtain a gel; and b) a second step of post-curing the gel to obtain the transparent solid substrate; and—recovering the transparent solid substrate from the casting mold assembly.