Cellulose Fibres With Layered Silicates for Controlled Active Release
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Solution Overview
Problem
Existing methods for incorporating active ingredients into cellulose molded bodies fail to achieve controlled release and are prone to phase separation and solvent washout during high-shear processes, especially when using aqueous media, and do not support the incorporation of volatile or chemosensitive ingredients.
Innovation Solution
A multi-stage process involving pulp dispersion in an aqueous solvent, homogenization of layered silicates, stabilization of active ingredient compositions, and controlled exfoliation to create a finely dispersed, stable mixture within the cellulose matrix, followed by spinning into shaped bodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If active ingredients are strongly encapsulated in cellulose matrix using hydrophobically modified pyrogenic silica, then encapsulation strength is improved, but controlled release capability deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the silica surface by using unmodified or differently modified silicas instead of hydrophobically modified silica. This parameter change alters the interaction mechanism between silica and active ingredients, enabling both strong encapsulation and controlled release through mechanisms other than hydrophobic interactions, such as hydrogen bonding or electrostatic interactions that can be tuned for controlled release.
Solution Approach 2:
The patent introduces nanoscale silica particles as intermediary structures that mediate between the cellulose matrix and active ingredients. These silica particles provide a controlled interface that allows both strong binding during processing and controlled release during use, acting as a bridge that reconciles the conflicting requirements of strong encapsulation and controlled release.
2Stability of the object's composition
If high-shear mixing is used to homogenize the mixture, then mixing homogeneity is improved, but phase separation and solvent washout increase
Solution Approach 1:
The patent performs preliminary stabilization of the active ingredient composition before high-shear mixing by incorporating stabilizing agents or pre-forming stable emulsions/suspensions. This preliminary action ensures that the active ingredients are protected against phase separation and solvent washout even when subjected to high-shear mixing conditions, allowing homogenization without the harmful effects.
Solution Approach 2:
The patent creates composite structures by combining cellulose, silica particles, and active ingredients into a multi-phase system where each component performs a specific function. The cellulose provides the matrix structure, silica provides stabilization and controlled release, and the composite nature of the material prevents phase separation during high-shear processing while maintaining homogeneity.
3Productivity
If volatile or chemosensitive active ingredients are incorporated during production, then production efficiency is improved, but ingredient stability deteriorates due to high temperatures and shear forces
Solution Approach 1:
The patent uses the cellulose matrix and silica particles as sacrificial protective structures that temporarily protect volatile or chemosensitive active ingredients during the high-temperature and high-shear production process. These protective structures are designed to be stable during processing but can be easily removed or degraded after production, allowing the active ingredients to survive the production process intact.
Solution Approach 2:
The patent provides beforehand cushioning by incorporating the active ingredients into a protected state before exposure to harsh production conditions. The cellulose-silica composite structure acts as a cushion that absorbs the mechanical and thermal stress during production, protecting the active ingredients from degradation while allowing efficient production processes to be used.
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
Enables controlled release of active ingredients and stable incorporation of volatile or chemosensitive substances, overcoming phase separation and solvent washout issues, allowing for targeted delivery of active ingredients in textile applications.
Implementation Method 1
controlled exfoliation of the layered silicate in the spinning solution
Implementation Method 2
the active ingredient composition is incorporated into the cellulose matrix in a finely dispersed form
Data Source
Figure 1
AI summary
Disclosed is a method for producing shaped cellulose articles from which an active ingredient is released with control. This is done by dispersing pulp in an aqueous direct solvent for cellulose to form a slurry. In parallel an organically modified or ion-exchange-activated phyllosilicate is homogenized in a direct solvent for cellulose with accompanying exfoliation by shearing and is then mixed with the slurried pulp. Separately a mixture of active ingredient and a lipophilic matrix material or a water-in-oil emulsion containing active ingredient is stabilized with inorganic or organic thickener and converted into a gel-like paste, which is then likewise mixed with the slurried pulp. Water is stripped from the mixture until all of the cellulose is dissolved. Then the mixture is formed into shaped articles in a solution spinning process and dried. The active ingredient is for example a cosmetic active ingredient, a fat-soluble vitamin or an apolar plant extract. Present in fine division within the shaped articles produced by the method are domains of active ingredient and matrix material or emulsion containing active ingredient. The shaped articles lend themselves to use particularly as functional fibres in knitted, woven and nonwoven fabrics, in paper and also in foils and membranes.