Release Coating Composition for Low-Temperature Silicone Curing
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Solution Overview
Problem
Conventional release liners formed from silicone compositions face challenges in cure speed and substrate compatibility due to high curing temperatures, limiting the types of substrates that can be used.
Innovation Solution
A composition comprising an organopolysiloxane with carbinol functional groups and a polyisocyanate is used to form a release coating, which can be cured at lower temperatures without forming a foam, allowing for faster curing and broader substrate compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional addition-curable silicone compositions are used to form release liners, then the release coating can be formed with good adhesive release properties, but the curing requires elevated temperatures that cause substrate softening or other undesirable effects
Solution Approach 1:
The patent changes the chemical parameters of the silicone composition by using carbinol-functional organopolysiloxane instead of conventional vinyl-functional polysiloxane. This parameter change enables the composition to cure at lower temperatures (below the substrate's softening point) while maintaining reliable adhesive release properties, thus resolving the contradiction between reliability and temperature requirements.
2Reliability
If elevated temperatures are used for curing conventional release liners, then the silicone composition cures adequately, but substrates susceptible to softening or other undesirable effects cannot be used
Solution Approach 1:
The invention changes the chemical composition parameters to use carbinol-functional organopolysiloxane with specific molecular weight and functionality ranges. This enables curing at lower temperatures, expanding substrate compatibility to include temperature-sensitive substrates while maintaining adequate cure reliability.
Solution Approach 2:
The new composition achieves universal applicability across diverse substrates by eliminating the temperature constraint. The carbinol-functional silicone composition can now be used on both temperature-resistant and temperature-sensitive substrates, including papers, films, and foams, making the release coating system universally adaptable.
3Productivity
If conventional release liners are formed at high speeds via coating process, then productivity increases, but cure speed becomes particularly important and may be limited by temperature requirements
Solution Approach 1:
The patent changes the chemical reactivity parameters of the silicone composition. The carbinol-functional organopolysiloxane reacts with polyisocyanate at lower temperatures and faster rates compared to conventional vinyl-functional polysiloxanes. This enables high-speed coating processes to be followed by rapid curing even at reduced temperatures, maintaining productivity while reducing cure time.
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 new composition enables faster curing and broader substrate compatibility, overcoming the limitations of conventional release liners by allowing for the use of substrates that are sensitive to high temperatures.
Implementation Method 1
The composition comprises (A) an organopolysiloxane having an average of at least two carbinol functional groups per molecule and (B) a polyisocyanate
Data Source
AI summary
A composition for forming a release coating comprises (A) an organopolysiloxane having an average of at least two carbinol functional groups per molecule. The organopolysiloxane (A) is present in the composition in an amount of from 50 to 99 wt. % based on the total weight of the composition. The composition further comprises (B) a polyisocyanate. The release coating formed with the composition is not a foam. A release coating formed with the composition is also disclosed. In addition, a method of preparing a coated substrate comprising a release coating disposed on a substrate, as well as the coated substrate formed in accordance with the method, are disclosed.