Foamable Silane-Modified Polymer Gasketing Without Isocyanates
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Solution Overview
Problem
Conventional chemically foamed gasketing and sealing materials rely on isocyanate reactions, which produce harmful residues, and alternative physical foaming methods use problematic propellants like fluoro-compounds, posing health and environmental risks.
Innovation Solution
A two-component foamable silane-modified polymer composition that generates hydrogen gas upon mixing, comprising silane-modified polymers, aminosilanes, and a reactive system, avoiding isocyanates and harmful propellants, with a catalyst system that forms siloxane bonds for strength and includes optional fillers and additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isocyanate reactions are used for chemical foaming, then foam structure and sealing properties are achieved, but harmful isocyanate residues remain
Solution Approach 1:
The patent changes the chemical composition parameters by replacing isocyanate-based systems with silane-modified polymer systems that cure through moisture-induced hydrolysis and condensation reactions, eliminating harmful isocyanate residues while maintaining foam structure and sealing properties
Solution Approach 2:
The patent converts the typically harmful moisture that causes premature curing into a beneficial curing agent by using silane-modified polymers that specifically react with atmospheric moisture to form stable siloxane crosslinks, enabling controlled foam expansion without harmful byproducts
2Reliability
If physical foaming with fluoro-compounds is used, then foam structure is achieved, but health and environmental risks increase
Solution Approach 1:
The patent changes the foaming mechanism from physical expansion using harmful fluoro-compound propellants to chemical expansion through controlled hydrogen generation from silane-water reactions, achieving identical foam structure without health and environmental risks
Solution Approach 2:
The patent substitutes the mechanical/physical foaming system (using compressed gas propellants) with a chemical reaction system that generates gas in-situ through controlled hydrolysis and condensation reactions, eliminating the need for harmful propellant storage and dispensing
3Ease of operation
If single-component systems are used, then application simplicity is improved, but control over foaming process and final properties deteriorates
Solution Approach 1:
The patent segments the formulation into two separate components: Component A containing the silane-modified polymer and Component B containing the crosslinker and catalyst, which are mixed immediately before application. This segmentation prevents premature reaction while enabling precise control over the foaming process through controlled mixing ratios and timing
Solution Approach 2:
The patent incorporates all necessary reaction components (silane groups, crosslinkers, catalysts) into the two components in advance, pre-configured so that upon mixing, the moisture-cure reaction proceeds automatically with optimal kinetics, combining application simplicity with process control
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 provides easy handling, excellent adhesion, high impermeability, effective sound and vibration damping, and a homogeneous cell structure, suitable for industrial applications without harmful by-products or substrate contact, particularly in automotive and mobility industries.
Implementation Method 1
The final strength of the material is initiated by the formation of siloxane of the SMPs
Implementation Method 2
The SMP is comprised of an hydrolysable silane group
Implementation Method 3
a reactive system which releases a gas upon mixing
Data Source
AI summary
The invention relates to a two-component foamable silane-modified polymer composition comprising: a component A comprising (a-1) at least one silane modified polymer, (a-2) at least one aminosilane or aminosilane oligomer, and (a-3) at least one foam stabilizer, (a-4) optionally at least one plasticizer, (a-5) optionally surface treated calcium carbonate, (a-6) optionally surfaced treated silica, (a-7) optionally at least one catalyst, (a-8) optionally at least one wax, a component B comprising (b-1) water, (b-2) at least one hydride organopolysiloxane, preferably at least one poly(methylhydrosiloxane), and (b-3) foam stabilizer, (b-4) optionally at least one plasticizer, (b-5) optionally surface treated calcium carbonate, (b-6) optionally surfaced treated silica, (b-7) optionally at least one phyllosilicate, (b-8) optionally at least one catalyst, (b-9) optionally at least one wax. The invention also relates to a method for preparing a silane-modified polymer foam attached to a part of assembly in situ, comprising the steps: I. preparing a two-component foamable silane-modified polymer composition according to any of claims 1 to 12; II. mixing the component A and component B at a reaction temperature from 15 to 100°C, preferably from 20 to 80°C, to form a reaction mixture; and III. applying the reaction mixture to at least one surface of part; to a silane-modified polymer foam obtained by said method, and to use of said two-component foamable silane-modified polymer composition or said silane-modified polymer foam in gasket, sealant or adhesive.