Polymer Substrate Impregnation via Aqueous Microemulsion

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Solution Overview

Problem

Existing methods for impregnating polymer substrates with organic additives face challenges such as high solvent usage, thermal degradation of additives, and increased process costs, particularly when using supercritical carbon dioxide, which requires high pressures and specialized equipment.

Innovation Solution

The use of an aqueous microemulsion comprising 50-70% water, 10-15% anionic surfactant, 10-30% co-surfactant, and 0.1-0.5% photoluminescent dyes, allowing for efficient impregnation of polymer substrates at low temperatures and pressures, reducing solvent usage, and enhancing additive interaction without the need for high quantities or specialized equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If bulk polymerization or solution polymerization methods are used to incorporate additives, then the additive can be integrated into the polymer matrix, but the high temperatures required cause thermal degradation of thermally labile additives

Engineering Contradiction:
Improveadditive stabilityVSAvoidpolymerization temperature
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The patent divides the additive incorporation process into two separate stages: (1) incorporating the additive into pre-formed polymer particles during emulsion polymerization, and (2) subsequent impregnation of the polymer substrate with additional additive. This segmentation allows the polymerization to occur at controlled temperatures while still achieving thorough additive integration, resolving the contradiction between temperature requirements and additive stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary incorporation of thermally labile additives into polymer particles during the emulsion polymerization process itself, before the polymer substrate is formed. This preliminary action ensures the additive is protected within the polymer matrix during subsequent processing, avoiding thermal degradation that would occur if additives were added after high-temperature processing.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If supercritical carbon dioxide is used for impregnation, then additive incorporation is achieved, but high pressures and specialized equipment are required

Engineering Contradiction:
Improveadditive concentrationVSAvoidequipment complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent changes the physical parameters of the impregnation process by using aqueous microemulsions at ambient temperature and pressure conditions, replacing the supercritical carbon dioxide method that requires high pressures (above 73 atm) and specialized equipment. The microemulsion system achieves effective additive delivery through its unique interfacial properties and ability to penetrate polymer matrices under mild conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces aqueous microemulsions as an intermediary carrier system that facilitates additive transfer to polymer substrates without requiring extreme conditions. The microemulsion acts as a mediator between the hydrophilic additive and the hydrophobic polymer matrix, enabling incorporation through gentle heating or stirring rather than high-pressure supercritical conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If conventional impregnation methods are used, then additive incorporation is achieved, but large quantities of solvent are required

Engineering Contradiction:
Improveadditive incorporationVSAvoidsolvent usage
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent creates local concentration of additives within the polymer matrix through microemulsion impregnation, where the additive is delivered in highly concentrated form at specific locations within the polymer substrate. This local quality approach reduces the total volume of solvent needed compared to conventional bulk impregnation methods, as the microemulsion droplets concentrate the additive at the polymer interface and within the matrix structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite aqueous microemulsion systems containing surfactants, co-surfactants, and additives that work synergistically to achieve effective impregnation with reduced solvent volumes. The composite nature of the microemulsion allows for optimized additive delivery efficiency, minimizing the total quantity of solvent required while maximizing additive incorporation into the polymer substrate.

Inventive Principle:
Principle #40Composite materials

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 achieves high concentrations of additives within the polymer substrate, operates at low temperatures and pressures, and eliminates the use of toxic solvents, thereby reducing environmental impact and process costs while maintaining additive stability.

Implementation Method 1

comprises completely immersing or partly immersing said polymer substrate in one aqueous microemulsion

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

achieves high concentrations of additives within the polymer substrate

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

wherein said aqueous microemulsion comprises: from 50% by weight to 70% by weight, of water

Methodology Applied
Scientific EffectMicroemulsion: Microemulsion

Data Source

PatentEP3131957B1Process for the impregnation of polymer substrates
Publication Date: 2024.07.10 ENI SPA

AI summary

Process for the impregnation of a polymer substrate including at least one polymer, which comprises putting said polymer substrate in contact with at least one aqueous emulsion, preferably an aqueous microemulsion, including at least one organic additive. The impregnated polymer substrate obtained from said process can be advantageously used for obtaining polymer end-products having improved aesthetic characteristics (for example, impregnation with at least one dye) or stability characteristics (for example, impregnation with at least one stabilizer), which can be used in various fields such as, for example, the optical field (e.g., advanced optical components, laser applications), the medical field (e.g., the release of pharmaceutical substances), the agricultural field (e.g., release of pesticides), fragrances (e.g., release of fragrances). More specifically, said polymer substrate can be used in luminescent solar concentrators (LSCs) which, in their turn, can be advantageously used together, for example, with photovoltaic cells (or solar cells), or photoelectrolytic cells, in solar devices (i.e. devices for exploiting solar energy). Furthermore, said luminescent solar concentrators (LSCs) can be advantageously used together, for example, with photovoltaic cells (or solar cells), in photovoltaic windows.