Crosslinked Polyether Siloxane Block Copolymers for Foam Stabilization
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Solution Overview
Problem
SiOC-based polyether siloxane block copolymers used in mechanically foamed polyurethane foams have low stability to hydrolysis and complex production processes, limiting their molecular weight and effectiveness as foam stabilizers.
Innovation Solution
Crosslinked polyether siloxane block copolymers are produced using Si-C chemistry through hydrosilylation of alpha-omega modified hydrogen siloxanes and polyethers, allowing for higher molecular weights and improved hydrolysis stability, enabling the production of fine-celled and stable polyurethane foams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SiOC-based polyether siloxane block copolymers are used as foam stabilizers, then foam stabilization is achieved, but hydrolysis stability is low and production processes are complex
Solution Approach 1:
The patent changes the chemical bond parameter from SiOC (silicon-oxygen-carbon) to SiC (silicon-carbon), fundamentally altering the chemical structure to achieve both high hydrolysis stability and effective foam stabilization. This parameter change resolves the contradiction by eliminating the hydrolytically unstable SiOC linkage while maintaining the foam stabilizing functionality through the SiC-based block copolymer structure.
Solution Approach 2:
The patent employs composite block copolymer structures combining polyether blocks with siloxane blocks linked via SiC bonds. This composite material approach allows the molecule to exhibit both the hydrolysis resistance of SiC bonds and the foam stabilizing properties of the block copolymer architecture, simultaneously achieving reliability and compositional stability.
2Reliability
If SiOC-based polyether siloxane block copolymers are used, then foam stabilization is achieved, but production processes are complex and molecular weight is limited
Solution Approach 1:
The patent changes the bonding parameter from SiOC to SiC, which simplifies the production process. The SiC-based block copolymers can be produced in customary fashion by hydrosilylation, avoiding the complex production processes required for SiOC-based polymers. This parameter change enables access to higher molecular weights and more consistent quality.
3Reliability
If linear polyether siloxane block copolymers are used, then foam stabilization is achieved, but molecular weight is limited due to chain terminations
Solution Approach 1:
The patent transitions from linear one-dimensional block copolymers to three-dimensional crosslinked networks. By introducing crosslinking through SiC bonds, the system eliminates chain termination limitations and enables the formation of high molecular weight structures with extended network architecture, thereby achieving higher effective molecular weights and improved foam stabilizing performance.
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 crosslinked polyether siloxane block copolymers provide high molecular weights, enhanced storage stability, and efficient mechanical foaming, resulting in consistent quality and process engineering advantages for producing polyurethane foams with improved cell structure and stability.
Implementation Method 1
SiC-based polyether siloxane block copolymers can be produced in customary fashion by hydrosilylation of alpha-omega modified hydrogen siloxanes with alpha-omega modified di(meth)allyl polyethers
Data Source
AI summary
Crosslinked polyether siloxane block copolymers are obtained by reacting an alpha-omega hydrogen siloxane with at least one higher-order hydrogen siloxane and at least one polyether in the presence of a hydrosilylation catalyst. These are described, and also use thereof as additives for producing polyurethane foams, particularly mechanically foamed polyurethane foams.