Track-Etched Membrane Dyeing for Dark Shades Without Pore Change
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Solution Overview
Problem
Existing methods for dyeing microporous track etched membranes with large pores and low porosity struggle to achieve dark shades without altering membrane parameters or affecting cell culture applications, as they often require high temperatures and difficult-to-remove solvents.
Innovation Solution
A method involving an aqueous dispersion dye system with azo and anthraquinone dyes, heated between 90 to 100°C, followed by exposure to 110 to 150°C for dye fixation, and subsequent use of sulfite-containing or alkaline solvents to remove residual dye, maintaining membrane integrity and suitability for cell culture systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high temperatures exceeding glass transition temperature are employed to achieve dark shade dyeing, then dye penetration and dyeing effect are improved, but membrane structural changes occur resulting in altered pore diameter or surface roughness
Solution Approach 1:
The patent modifies the chemical composition parameters of the dyeing system by introducing carrier substances (carboxylic acids or their derivatives) and specific additives that enable effective dyeing at reduced temperatures. This parameter change allows achieving dark shade dyeing effects without exceeding the membrane's glass transition temperature, thereby preventing structural degradation while maintaining desired color intensity.
Solution Approach 2:
The patent employs carrier substances (such as carboxylic acids or their derivatives) as intermediary agents that facilitate dye penetration into the membrane at lower temperatures. These carriers act as mediators between the dye and membrane polymer chains, enabling effective dyeing without requiring high temperatures that would compromise membrane structural stability.
2Illumination intensity
If solvents with higher boiling alcohols or hydrocarbons are used to achieve dark shade dyeing, then dye penetration is improved, but solvent removal becomes difficult and negatively influences cell culture applications
Solution Approach 1:
The patent fundamentally changes the solvent system parameter from high-boiling alcohols or hydrocarbons to water-based aqueous systems. This parameter change enables easy solvent removal through evaporation or drying without leaving harmful residues, while still achieving dark shade dyeing effects when combined with carrier substances and optimized dyeing conditions.
Solution Approach 2:
The patent employs water as a disposable, easily removable solvent that leaves no harmful residues. Water serves as a temporary medium during the dyeing process that can be completely eliminated through simple drying, unlike persistent organic solvents that require complex removal procedures and contaminate the final membrane product.
3Illumination intensity
If disperse dyes in aqueous/alcoholic systems are used for small pore membranes, then dark shades are achieved through dyed pore walls, but this approach is insufficient for large pore membranes with fewer pores
Solution Approach 1:
The patent changes the fundamental parameter of the dyeing mechanism by introducing carrier substances that enable dye molecules to interact with and penetrate the bulk membrane material itself, rather than relying solely on pore wall adsorption. This parameter change makes the process adaptable to large pore membranes where the limited number of pores cannot provide sufficient light blocking, as the dye now colors the entire membrane matrix.
Solution Approach 2:
The patent creates a universal dyeing method that works effectively for both small pore and large pore membranes by combining carrier substances with disperse dyes. This multi-functional approach allows the same dyeing system to achieve dark shades through different mechanisms: pore wall dyeing for small pore membranes and bulk material dyeing for large pore membranes, providing broad adaptability across different membrane types.
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
Achieves dark shade dyeing with significant light transmission reduction without altering membrane parameters, ensuring compatibility with sensitive cell culture applications and allowing for continuous roll-to-roll processing.
Implementation Method 1
heating the membrane by exposing it to a temperature between 110 and 150°C for 20 to 90 minutes thereafter
Implementation Method 2
contacting the membrane with an aqueous dispersion dye system at a temperature between 90 to 100°C for a time period sufficient to produce a desired transmission spectra
Implementation Method 3
heating the membrane by exposing it to a temperature between 110 and 150°C for 20 to 90 minutes thereafter
Implementation Method 4
removal of residual dye from the membrane surfaces by reducing with sulfite-containing solutions
Data Source
AI summary
Methods for dyeing of microporous track etched membranes are provided. In particular, these methods are suitable for dark shade dyeing of membranes having large pores with low porosity. Desirably, such methods provide dyed membranes wherein the membrane parameters are not significantly changed as compared to those prior to dyeing. Likewise, the resultant dyed membranes exhibit no negative influence on sensitive cell culture system applications.