Aqueous Silicone Dispersion Tacky Layer Formation
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Solution Overview
Problem
Existing aqueous silicone dispersions fail to form a tacky layer effectively on drying, which is essential for adhesive applications, and there is a need for a method to create a stable and efficient adhesive for both cosmetic and pharmaceutical uses.
Innovation Solution
Aqueous silicone dispersion is prepared by mixing an alkenyl-containing organopolysiloxane with an SiH-containing siloxane, a hydrosilylation catalyst, and a polymeric film former, along with a surfactant, to form a colloidal emulsion that reacts to create a tacky, elastomeric silicone layer upon drying, suitable for adhesive applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing aqueous silicone dispersions are used, then the composition can be applied to skin, but they fail to form a tacky layer effectively on drying
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific crosslinking agents and adhesion promoters alongside the silicone emulsion, transforming the formulation from a simple silicone-based product to a multi-component system with optimized chemical ratios that enable effective tacky layer formation upon drying
Solution Approach 2:
The invention creates a composite adhesive system combining silicone emulsion particles with crosslinking agents and adhesion promoters in an aqueous phase, where the interaction between these different material components produces the desired tacky layer properties that neither component could achieve alone
2Reliability
If crosslinking agents and catalysts are added to form a stable adhesive layer, then adhesion improves, but the formulation complexity increases
Solution Approach 1:
The patent introduces adhesion promoters as intermediary substances that mediate between the silicone emulsion and the substrate, facilitating strong adhesion without requiring complex crosslinking chemistry. These promoters act as bridging molecules that simplify the overall formulation while maintaining reliable adhesive performance
3Ease of operation
If a tacky layer is formed for adhesive applications, then dressing adhesion to skin is achieved, but the formulation requires multiple components
Solution Approach 1:
The patent merges multiple functional components (silicone emulsion, crosslinking agents, adhesion promoters, and aqueous phase) into a single integrated aqueous dispersion formulation that can be applied as one homogeneous composition, simplifying the application process despite the multi-component nature of the formulation
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
The resulting tacky silicone layer is effective for adhering dressings to skin and delivering pharmaceutical or cosmetic active ingredients topically, offering a stable and efficient adhesive solution with low platinum catalyst requirements and fast curing properties.
Implementation Method 1
a hydrosilylation catalyst is added simultaneously with the aqueous polymeric film former and surfactant or is added to the aqueous silicone emulsion subsequently, and the alkenyl-containing organopolysiloxane (a) and the SiH containing siloxane (b) being reacted together in the aqueous silicone emulsion
Implementation Method 2
emulsifying the resulting mixture in an aqueous solution of a polymeric film former and a surfactant of molecular weight below 1600 to form an aqueous silicone emulsion
Implementation Method 3
allowing a sufficient amount of water in the aqueous phase to evaporate from the coating on the substrate so as to form a tacky layer on the dressing
Data Source
AI summary
An aqueous dispersion comprises a silicone composition dispersed in an aqueous phase. The silicone composition comprises a product of a reaction of (a) an alkenyl-containing organopolysiloxane having an average per molecule of at least 2 alkenyl groups and (b) an Si H containing siloxane having an average per molecule of at least 2 Si H moieties. The dispersion also comprises a hydrosilylation catalyst, a polymeric film former and a surfactant of molecular weight below 1600. The composition is stabilised in dispersion form by the surfactant dissolved in the aqueous phase and the polymeric film former, and is capable of forming a tacky layer on drying.