Silane-Functional Polymer Composition for Rapid Moisture Curing
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Solution Overview
Problem
Current silane-functional polymers used in moisture-curing adhesives and coatings have high viscosity, slow curing rates, and require harmful catalysts like organotin compounds and DBU, which are environmentally hazardous and less effective.
Innovation Solution
A composition of two different silane-functional polymers with varying reactivity levels, where one polymer's high reactivity is transmitted to the other, allowing for rapid curing without the need for hazardous catalysts, resulting in a strong, elastic, and thermally stable material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If silane-functional polymers with high urethane groups are used, then crosslinking speed is improved, but viscosity increases and processability deteriorates
Solution Approach 1:
The invention divides the silane-functional polymer system into two separate components: a low-viscosity silane-functional polymer (P1) providing processability and a high-activity polymer (P2) providing crosslinking speed. This segmentation allows each component to optimize its function without compromising the other, resolving the contradiction between viscosity and crosslinking speed.
Solution Approach 2:
The invention creates a composite system combining two different silane-functional polymers with complementary properties. Polymer P1 (low viscosity) and polymer P2 (high activity) work together synergistically, where P1 provides the bulk material properties and processability while P2 accelerates crosslinking, achieving both low viscosity and high crosslinking speed simultaneously.
2Productivity
If organotin compounds are used as catalysts, then curing rate is improved, but harmful effects increase
Solution Approach 1:
The invention replaces harmful organotin catalysts with a benign water-based curing mechanism. The high-activity polymer P2 enables rapid curing through moisture reaction alone, converting a potentially harmful catalytic process into a safe environmental process while maintaining high curing rates.
Solution Approach 2:
The invention eliminates the need for persistent harmful catalysts by using a self-limiting moisture-curing mechanism. The curing reaction consumes water from the environment and stops when complete, avoiding the environmental persistence and accumulation issues associated with organotin catalysts.
3Productivity
If DBU is used as catalyst, then curing rate is improved, but harmful effects and separation tendency increase
Solution Approach 1:
The invention extracts and removes the harmful DBU catalyst from the system entirely. Instead of relying on strong base catalysts, the high-activity polymer P2 enables curing through moisture reaction alone, eliminating the source of separation, odor, and environmental harm while maintaining rapid curing.
4Ease of operation
If low-viscosity silane-functional polymers are used, then processability is improved, but crosslinking speed deteriorates
Solution Approach 1:
The invention segments the functional requirements into two separate polymers: P1 provides low viscosity and processability, while P2 provides high crosslinking activity. This division of labor allows each polymer to optimize its specific function without compromising the other's performance.
Solution Approach 2:
The invention creates a composite polymer system where low-viscosity P1 and high-activity P2 work together. The combination achieves both low viscosity (from P1) and fast crosslinking (from P2), resolving the contradiction that plagues single-component systems.
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 rapid curing with good mechanical properties and thermal stability, eliminating the need for harmful catalysts and reducing viscosity, making it suitable for construction and industrial applications.
Implementation Method 1
a composition of two different silane-functional polymers... which cures surprisingly rapidly with moisture to give an elastic material
Data Source
AI summary
A composition containing two different silane-functional polymers, only one of the two polymers having terminal groups of formula (I). The composition has a surprisingly rapid skin forming time and low viscosity, crosslinks quickly even without the use of EHS-critical catalysts such as organotin compounds or DBU, and cures to a non-sticky material with good strength and elasticity. Also relates to a method for accelerating the curing of a silane-crosslinking composition by adding to it a further silane-functional polymer having terminal groups of formula (I).