High-Index Plastic Lens Dyeing With Low-Water Sublimation Ink
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Solution Overview
Problem
Existing methods for dyeing plastic lenses with high refractive indices, such as those above 1.7, often result in uneven dyeing due to pigment crystallization and temperature variations, particularly when using sublimation dyes, which can lead to non-uniform color distribution.
Innovation Solution
A process involving coating a substrate with a sublimation dye ink at 60°C or lower, reducing the water content to 50% or less, and sublimating the dye under vacuum conditions to ensure uniform dyeing of plastic lenses with refractive indices above 1.7.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sublimation dye process is used to achieve uniform dying on high refractive index plastic lenses, then the density of dyeing is improved, but pigment crystallization occurs on the lens surface causing uneven dying
Solution Approach 1:
The patent changes the water content parameter of the sublimation dye ink from conventional high levels (70-90%) to a controlled low level (50% or less). This parameter change prevents pigment crystallization while maintaining uniform dyeing density on high refractive index plastic lenses (1.7 or greater). The reduced water content ensures proper surfactant-dye-pigment interaction during sublimation without causing harmful crystallization effects.
Solution Approach 2:
The patent uses a composite ink formulation containing sublimation dye, surfactant, and pigment in specific proportions with controlled water content (50% or less). This composite material structure ensures that the surfactant remains effective at low water content to prevent pigment crystallization while the sublimation dye provides uniform coloring on high refractive index lenses, resolving the contradiction between dyeing density and crystallization prevention.
2Ease of operation
If a high water content ink is used in the coating process, then the ease of coating is improved, but the uniformity of water distribution deteriorates causing non-uniform dyeing
Solution Approach 1:
The patent optimizes the water content parameter to 50% or less of the entire ink composition. This parameter change maintains sufficient coating processability while ensuring uniform water distribution throughout the ink. The controlled water level prevents the segregation and uneven distribution that occurs in high water content inks, thereby achieving both ease of coating and manufacturing precision.
3Ease of manufacture
If the water content in the ink is not controlled, then the simplicity of the process is maintained, but the quality of dyeing uniformity deteriorates
Solution Approach 1:
The patent establishes a specific water content parameter (50% or less of entire ink) that balances process simplicity with dyeing uniformity. This parameter control is straightforward to implement in manufacturing while dramatically improving dyeing quality by preventing pigment crystallization and ensuring uniform surfactant distribution. The simplicity of controlling water content during ink preparation makes this precision achievable without complex additional process steps.
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 process enables uniform and dense dyeing of plastic lenses with refractive indices between 1.7 and 1.8 without unevenness, improving the consistency and quality of the dyeing process.
Implementation Method 1
sublimating the sublimation dye in the ink comprising a sublimation dye coating the substrate by heating the substrate obtained after Step (2)
Implementation Method 2
decreasing content of water in the ink comprising sublimation dye coating the substrate to 50% by mass or less of the entire ink
Data Source
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AI summary
A process which enables a plastic lenses having a refractive index of 1.7 or greater and, in particular, plastic lenses having a refractive index of 1.7 to 1.8 to be dyed uniformly to a great density without unevenness, which is, specifically, a process for producing a dyed plastic lens which comprises conducting following steps (1), (2) and (3) in this order: Step (1): a step comprising coating a substrate at 60°C or lower with an ink comprising a sublimation dye; Step (2): a step comprising decreasing content of water in the ink comprising sublimation dye coating the substrate to 50% by mass or less of the entire ink; and Step (3): a step comprising, after placing a plastic lens in a manner such that a face for dying of the lens and a face of the substrate coated with the ink comprising a sublimation dye face each other, sublimating the sublimation dye in the ink comprising a sublimation dye coating the substrate by heating the substrate obtained after Step (2) under a degree of vacuum of about 1×104 Pa or smaller to dye the plastic lens.