Silicone Elastomer Stabilization Against Catalyst Blackening
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Solution Overview
Problem
Two-component polyaddition compositions catalyzed by platinum-based catalysts experience a slowdown in crosslinking kinetics during long storage, leading to extended curing times and degradation of physical properties, along with the issue of blackening of the catalyst-containing part, which affects the accuracy and usability of dental impression materials.
Innovation Solution
Incorporating a stabilizing agent, such as corn starch, in a specific concentration range within the composition to maintain the kinetics of the polyaddition reaction and prevent blackening, thereby ensuring stability and performance during storage and use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If two-component polyaddition compositions are stored for long periods, then the composition remains stable for use, but the crosslinking kinetics slow down and curing time extends
Solution Approach 1:
The patent applies preliminary action by incorporating a stabilizing agent into the composition before storage to prevent the degradation of crosslinking kinetics. The stabilizing agent is added in advance to counteract the natural slowdown of the platinum-catalyzed polyaddition reaction during long-term storage, ensuring that the curing time remains acceptable when the material is eventually used.
Solution Approach 2:
The patent changes the chemical parameter of the system by introducing a stabilizing agent that modifies the reaction kinetics. This agent interacts with the platinum catalyst or the reacting species to maintain the crosslinking rate at acceptable levels during storage, effectively changing the temporal behavior of the curing process without altering the fundamental chemistry.
2Duration of action of stationary object
If two-component polyaddition compositions are stored for long periods, then the composition remains available for use, but the physical properties of the elastomer degrade
Solution Approach 1:
The stabilizing agent is incorporated in advance to prevent the degradation of physical properties during storage. By being present before any degradation occurs, the agent protects the elastomer's mechanical and physical characteristics from deteriorating over time, ensuring reliable performance when the material is used.
Solution Approach 2:
The stabilizing agent acts as a sacrificial component that may undergo changes or be consumed during storage to protect the main elastomer system. This disposable-like approach allows the stabilizer to absorb degradation effects, preserving the reliability of the primary material.
3Productivity
If platinum-based catalysts are used for polyaddition reactions, then crosslinking efficiency is improved, but blackening of the catalyst-containing part occurs during storage
Solution Approach 1:
The stabilizing agent serves as an intermediary between the platinum catalyst and the environment during storage. It mediates the interaction by preventing the chemical or physical changes that cause blackening, while allowing the catalyst to maintain its crosslinking efficiency. The stabilizer protects the catalyst system from degradation without interfering with its primary function.
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 composition remains stable and functional during storage, maintaining the desired working and curing times, and preventing blackening, thus ensuring the quality and accuracy of dental impressions.
Implementation Method 1
Incorporating a stabilizing agent, such as corn starch, in a specific concentration range within the composition to maintain the kinetics of the polyaddition reaction
Implementation Method 2
prevent blackening, thereby ensuring stability and performance during storage and use
Implementation Method 3
The polymerization, crosslinking or hardening reaction of such compositions starts when the two parts are mixed, i.e. the platinum-based catalyst, the polyorganosiloxane having, per molecule, at least two hydrogen atoms linked to a silicon atom and polyorganosiloxane having, per molecule, at least two alkenyl groups
Implementation Method 4
elastomers or silicone materials obtained by crosslinking and/or hardening at room temperature... The resulting mass then loses its pasty consistency and takes on a 'rubbery' and elastic consistency during hardening
Data Source
AI summary
The field of the present invention is that of organopolysiloxane compositions that are capable of cross-linking and/or of hardening by polyaddition reactions so as to produce elastomers or materials made of silicone, which are useful in particular for making a dental impression in the context of the preparing of prostheses.