Reactive Plasticizer for Silane Sealants
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Solution Overview
Problem
Existing one-component moisture curable compositions based on silane-terminated polymers face challenges in reducing the use of conventional plasticizers like phthalates, which can cause bleeding and negatively impact the mechanical and application properties of sealants.
Innovation Solution
The use of reactive plasticizers based on monofunctional alkoxy silane-terminated polymers, which react with silane-terminated polymers to improve flexibility and mechanical properties while reducing viscosity and the need for conventional plasticizers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional plasticizers like phthalates are used to improve flexibility and reduce viscosity, then the mechanical and application properties are improved, but health hazards and bleeding issues occur
Solution Approach 1:
The patent changes the chemical composition parameters by replacing conventional phthalate-based plasticizers with reactive plasticizers containing silane groups. This substitution maintains the desired flexibility and viscosity reduction while eliminating the harmful bleeding effects and health hazards associated with phthalates. The reactive plasticizers undergo crosslinking reactions that fundamentally alter the chemical structure and behavior of the plasticizer component.
Solution Approach 2:
The patent converts the potential harm of plasticizer migration (bleeding) into a benefit by using reactive plasticizers that crosslink with the polymer matrix. The crosslinking reaction prevents migration while the silane groups provide reactive functionality that enhances adhesion to substrates and overcoats, turning what would be a harmful migrating component into a beneficial bonded component.
2Object-affected harmful factors
If reactive plasticizers based on high molecular weight monools are used to reduce bleeding, then health hazards are reduced, but mechanical properties and application properties deteriorate
Solution Approach 1:
The patent optimizes the molecular weight parameter of the monool used to synthesize reactive plasticizers. By selecting monools with specific molecular weights and adjusting the synthesis conditions, the patent achieves a balance where the reactive plasticizer provides sufficient crosslinking to prevent bleeding while maintaining adequate chain length to preserve mechanical properties like tensile strength and elongation.
Solution Approach 2:
The patent creates a composite system where reactive plasticizers with optimized molecular characteristics are combined with silane-terminated polymers. The composite structure allows the reactive plasticizer to contribute to crosslinking density (preventing bleeding) while the polymer matrix maintains the bulk mechanical properties. The synergistic interaction between the two components resolves the contradiction between bleeding reduction and mechanical strength.
3Ease of operation
If reactive plasticizers are used to reduce viscosity and improve flexibility, then application properties are improved, but molecular weight optimization becomes critical
Solution Approach 1:
The patent systematically varies and optimizes multiple parameters including monool molecular weight, silane group type, and reaction conditions to achieve the desired viscosity reduction while maintaining flexibility. By establishing specific parameter ranges and relationships, the patent simplifies the synthesis process despite the multiple variables involved, providing a clear framework for producing reactive plasticizers with consistent 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 reactive plasticizers enhance the mechanical and application properties of the sealants, improve adhesion with paints, and reduce delamination, while minimizing bleeding and the use of health-hazardous plasticizers.
Implementation Method 1
Polymers containing reactive silane groups are in particular organic polymers containing reactive silane groups, which are also referred to as 'silane-functional polymers', 'silane-modified polymers' (SMP) or 'silane-terminated polymers' (STP). Compositions containing these polymers harden via crosslinking reactions of the reactive silane groups on the polymers, which hydrolyze under the influence of moisture
Implementation Method 2
condense with one another as silanol groups and thus form a covalently bonded network
Implementation Method 3
Compositions containing these polymers harden via crosslinking reactions of the reactive silane groups on the polymers, which hydrolyze under the influence of moisture, condense with one another as silanol groups and thus form a covalently bonded network
Data Source
AI summary
The invention relates to a one-component moisture-curable composition, comprising at least one organic polymer containing on average at least two reactive silane end groups, at least one reactive plasticizer containing on average 1 to 1.5 reactive silane end groups, optionally a filler and optionally at least one additive. The one-component moisture curable composition can be formulated to show excellent properties for application in non-bleed sealants. The invention also reduces the amount of hazardous phthalate-containing plasticizers.