Silane Polymer Composition with Hybrid Catalyst System
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Solution Overview
Problem
Moisture-curing compositions based on silane-functional polymers with titanates exhibit superior mechanical properties but at the cost of reduced curing reactivity compared to organotin compounds, necessitating a solution that enhances mechanical properties while maintaining skin formation time.
Innovation Solution
A composition comprising silane-functional polymers, organotin compounds, and titanates in precisely defined parts by weight, optimizing mechanical properties in the cured state without altering skin formation time, using organotin compounds in the range of 0.01 to 0.15% and titanates in the range of 0.05 to 1% by weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If titanates are used as catalyst for crosslinking, then mechanical properties are improved, but curing reactivity is reduced
Solution Approach 1:
The patent combines two different catalyst systems (organotin compounds and titanates) into a single hybrid system. This merging allows the composition to benefit from both catalysts: organotin compounds provide high reactivity and fast skin formation, while titanates contribute to superior mechanical properties. The synergistic effect of the combined catalyst system resolves the contradiction by achieving both fast curing and excellent mechanical performance simultaneously.
Solution Approach 2:
The patent creates a composite catalyst system by combining organotin compounds and titanates in specific weight ratios. This composite approach allows the system to exhibit properties that neither catalyst alone could provide. The organotin compound ensures rapid initial curing and skin formation, while the titanate component enhances the final mechanical strength and durability of the cured composition.
2Speed
If organotin compounds are used as catalyst, then curing reactivity is improved, but mechanical properties are reduced
Solution Approach 1:
The patent merges the advantages of organotin compounds (high reactivity) with titanates (superior mechanical properties) in a single catalyst system. By combining these two catalyst types in optimized proportions, the composition achieves both fast skin formation and excellent mechanical strength, eliminating the need to choose between reactivity and mechanical performance.
3Strength
If titanates are used as catalyst, then mechanical properties are improved, but skin formation time is increased
Solution Approach 1:
The hybrid catalyst system combines the fast skin formation capability of organotin compounds with the mechanical property enhancement of titanates. The organotin compound rapidly initiates crosslinking and forms skin quickly, while the titanate ensures the final cured product achieves high mechanical strength, thus resolving the time-strength contradiction.
4Loss of time
If organotin compounds are used as catalyst, then skin formation time is reduced, but mechanical properties are reduced
Solution Approach 1:
The patent merges the rapid skin formation effect of organotin compounds with the mechanical property enhancement of titanates in a synergistic catalyst system. This combination allows the composition to achieve both fast processing (short skin formation time) and excellent final mechanical properties, eliminating the trade-off between speed and strength.
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 achieves improved mechanical properties in the cured state with a short skin formation time, demonstrating tensile strength of ≥2 MPa, elongation at break of ≥450%, and lap shear strength of ≥1.5 MPa, while maintaining processing efficiency.
Implementation Method 1
The silane groups have the property of hydrolyzing when they come into contact with moisture. Organosilanols are formed, i.e. organosilicon compounds containing one or more silanol groups (Si-OH groups), and, through subsequent condensation reactions, organosiloxanes
Implementation Method 2
through subsequent condensation reactions, organosiloxanes, i.e. organosilicon compounds containing one or more siloxane groups (Si-O-Si groups)
Implementation Method 3
Organotin compounds in particular are used as catalyst or accelerator systems for the crosslinking of compositions containing silane-functional polymers under the influence of water. The use of titanates for this purpose is also known.
Data Source
AI summary
The present invention relates to a composition comprising a) at least one silane-functional polymer P, b) at least one organotin compound, and also c) at least one titanate, where the proportion of organotin compound is from 0.01 to 0.15% by weight and the proportion of titanate is from 0.05 to 1% by weight, based in each case on the entire composition.