Branched Polyorganosiloxane Release Coating for Low Migration
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Solution Overview
Problem
Known silicone release coatings face challenges with ultra-low release force, as they often suffer from migration issues, which can contaminate pressure-sensitive adhesives and affect their performance in applications like tape release and label adhesion.
Innovation Solution
A release coating composition comprising a combination of branched polyorganosiloxanes and silsesquioxanes, with a specific molar ratio of silicon-bonded hydrogen to aliphatically unsaturated groups, a platinum group metal catalyst, and an inhibitor, which is cured via thermal addition to form a release liner with reduced release force and maintained adhesion strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a release coating composition is formulated to have desirable ultra-low release force, then the release force is reduced, but the coating may suffer from migration
Solution Approach 1:
The invention uses a composite coating system comprising a siloxane polymer matrix combined with specific release agents (silicones, fluorocarbons, or waxes) to achieve ultra-low release force while preventing migration. The composite formulation creates a synergistic effect where the polymer provides structural integrity and the release agents provide low adhesion properties without migrating
Solution Approach 2:
The invention changes the chemical and physical parameters of the release coating by using a siloxane polymer base with specific molecular weight and viscosity ranges, combined with controlled amounts of release agents (0.1-10 parts per 100 parts polymer). This parameter optimization allows achieving ultra-low release force while maintaining coating stability and preventing migration
2Force
If the release coating has low release force, then it provides good release properties, but the subsequent adhesion strength may be affected
Solution Approach 1:
The invention applies local quality by creating different functional zones within the coating system: the siloxane polymer matrix provides the base coating structure with good adhesion to the substrate, while the incorporated release agents provide localized low-adhesion properties at the coating-adhesive interface. This allows the coating to exhibit low release force where needed while maintaining strong bonding to the substrate
3Ease of operation
If a conventional silicone release coating is used, then it provides basic release properties, but it suffers from migration that contaminates pressure-sensitive adhesives
Solution Approach 1:
The invention replaces conventional silicone release coatings with a siloxane polymer-based coating system that uses smaller, less migratory release agent molecules (0.1-10 parts per 100 parts polymer). This formulation provides the necessary release properties while the release agents remain trapped in the polymer matrix, preventing migration contamination of the adhesive layer
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 a lower release force while maintaining good subsequent adhesion strength, effectively preventing migration and ensuring reliable performance in applications such as tape release and label adhesion.
Implementation Method 1
cured via hydrosilylation reaction to form a release liner
Implementation Method 2
an organometallic catalyst or a complex thereof with a siloxane
Implementation Method 3
0.001 to 1 parts by weight, per 100 parts of starting material A), of an inhibitor
Data Source
Figure 1
AI summary
Provided is a release coating composition including a combination of branched polyorganosiloxanes. The first branched siloxane in the combination is an MDQ siloxane of unit formula: (R 1 3SiO 1/2) a(R 2R 1 2SiO 1/2) b(R 1 2SiO 2/2) c(SiO 4/2) d, a≥0, b＞0, c≤995, and d＞0. The second branched siloxane in the combination is an MDT silsesquioxane of unit formula: (R 1 3SiO 1/2) e(R 2R 1 2SiO 1/2) f(R 1 2SiO 2/2) g(R 1SiO 3/2) h, e≥0, f＞0, g≤995, and h＞0. Each R 1 is independently a monovalent hydrocarbon group free of aliphatic unsaturation and each R 2 is an aliphatically unsaturated hydrocarbon group. The release coating composition further includes a crosslinker having at least 3 silicon-bonded hydrogen atoms per molecule, a platinum group metal catalyst and an inhibitor.