Functional Polysiloxanes for Low-Temperature Coating Adhesion
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Solution Overview
Problem
Existing silicone coatings exhibit poor adhesion to substrates such as paper and polymeric materials, particularly when using poly(dimethylsiloxane-co-methylhydrogensiloxane) copolymer crosslinkers, and the formation of silyl ethers is reduced at low catalyst loading and curing temperatures, limiting effective anchorage.
Innovation Solution
The use of functional polysiloxanes with anhydride functionality selectively located at the ends of the polymer chain and specific ratios of methylhydridosiloxane to dimethylsiloxane, enhancing adhesion through hydrosilylation reactions catalyzed by platinum-based catalysts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If poly(dimethylsiloxane-co-methylhydrogensiloxane) copolymer crosslinkers are used to improve adhesion, then adhesion performance is enhanced, but curing speed decreases and line-speed must be reduced
Solution Approach 1:
The patent changes the chemical structure parameters of the crosslinker by using poly(methylhydrogensiloxane) homopolymer instead of copolymer, and by controlling the molecular weight and functionality of the crosslinker to optimize both adhesion performance and curing speed, allowing maintenance of line-speed while achieving good adhesion
Solution Approach 2:
The patent uses composite crosslinking systems combining siloxane crosslinkers with other reactive components to achieve both strong adhesion and fast curing, creating a multi-component system that balances performance and productivity
2Reliability
If excess siloxane crosslinker bearing SiH moieties is added to improve anchorage, then adhesion to substrate is improved, but curing time increases and catalyst loading must be increased
Solution Approach 1:
The patent optimizes the concentration and functionality of SiH moieties in the crosslinker to achieve sufficient anchorage without excessive curing time, and adjusts catalyst loading to balance reaction speed and adhesion quality
Solution Approach 2:
The patent introduces silane coupling agents as intermediaries that facilitate bond formation between the siloxane coating and substrate, improving anchorage efficiency without requiring excessive crosslinker content or extended curing time
3Reliability
If silyl ether formation is promoted to enhance anchorage, then substrate adhesion is improved, but effectiveness is reduced at low catalyst loading and low curing temperatures
Solution Approach 1:
The patent modifies the chemical reactivity parameters of the crosslinking system by selecting crosslinkers with optimized SiH group reactivity and adjusting catalyst types to enable effective silyl ether formation across a broader temperature range, including low temperatures and low catalyst loading conditions
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
Improves adhesion properties of silicone coatings on paper and polymeric substrates, allowing for faster curing and maintaining effective anchorage without reducing line-speed, even at low catalyst loading and temperatures.
Implementation Method 1
enhancing adhesion through hydrosilylation reactions catalyzed by platinum-based catalysts
Implementation Method 2
enhancing adhesion through hydrosilylation reactions catalyzed by platinum-based catalysts
Data Source
AI summary
The present invention relates to a functional polyorganosiloxane and the use thereof, in particular, as adhesion promotor in curable silicone compositions.