Release Coating Organopolysiloxane With Low-Platinum Cure
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Solution Overview
Problem
Existing addition-curable organopolysiloxane compositions require high amounts of platinum catalysts, leading to high costs and inefficiencies due to incomplete curing and migration of unreacted siloxane, which affects adhesive properties and release force.
Innovation Solution
An organopolysiloxane composition with alkenyl groups and (meth)acrylic groups, combined with a platinum group metal catalyst in a minor amount, ensures sufficient curing and maintains release force comparable to traditional compositions, even on substrates with catalyst poisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the amount of platinum catalyst is reduced below 60 ppm, then manufacturing cost decreases, but curing reaction becomes insufficient leading to soft cured film and high release force
Solution Approach 1:
The patent changes the chemical structure parameters of the organopolysiloxane by introducing specific alkenyl groups (vinyl, allyl, propenyl, butenyl) and controlling the ratio of Si-H groups to alkenyl groups within 0.5:1 to 5:1. This parameter optimization enables sufficient curing reaction even with reduced platinum catalyst amounts of 1-100 ppm, resolving the contradiction between cost reduction and curing sufficiency.
Solution Approach 2:
The patent creates a composite system combining organopolysiloxane with specific alkenyl groups and Si-H groups in controlled ratios, forming a synergistic composition that enhances curing efficiency. This composite approach allows the system to achieve complete curing with minimal platinum catalyst, addressing both cost and reliability requirements.
2Ease of manufacture
If the amount of platinum catalyst is reduced, then manufacturing cost decreases, but unreacted organopolysiloxane increases causing migration to adhesive surface
Solution Approach 1:
By optimizing the ratio of Si-H groups to alkenyl groups within 0.5:1 to 5:1 and selecting specific alkenyl group types, the patent ensures complete reaction of organopolysiloxane components even with reduced catalyst amounts. This prevents unreacted material from remaining in the cured film and migrating to the adhesive surface, while still achieving cost reduction through lower platinum usage.
3Adaptability or versatility
If nitrogen, sulfur, or phosphorus compounds are present on the substrate, then substrate functionality increases, but platinum catalyst activity is suppressed reducing curing progress
Solution Approach 1:
The patent optimizes the ratio of Si-H groups to alkenyl groups within 0.5:1 to 5:1 and selects specific alkenyl group types (vinyl, allyl, propenyl, butenyl) to enhance the reactivity and catalytic efficiency of the system. This parameter optimization compensates for the presence of catalyst poisons like nitrogen, sulfur, and phosphorus compounds, maintaining reliable curing progress even on substrates with these contaminants.
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 efficient curing with reduced platinum usage, lowering costs and maintaining adhesive properties while reducing unreacted siloxane migration, thus enhancing release performance.
Implementation Method 1
an addition-curable organopolysiloxane composition which cures with a minor amount of platinum catalyst
Implementation Method 2
an addition reaction between an alkenyl group-containing organopolysiloxane and an organohydrogenpolysiloxane in the presence of a platinum base compound catalyst
Data Source
AI summary
One of the purposes of the present invention is to provide an addition-curable organopolysiloxane composition which cures sufficiently with a minor amount of platinum group metal catalyst to exert satisfactory adhesion and provides a cured film having a release force comparable to the prior art cured film, and to provide an addition-curable organopolysiloxane composition which allows the sufficient progress of addition cure even on a substrate comprising a catalyst poison component so as to be suitable for providing a release coating for silicone rubber and release paper or release film. That is, the present invention provides an addition-curable organopolysiloxane composition comprising components (A) to (C): (A) an organopolysiloxane having two or more alkenyl groups each bonded to a silicon atom per molecule and having 0.01 to 2.9, as an average, (meth)acrylic groups, (B) an organohydrogenpolysiloxane having two or more hydrogen atoms each bonded to a silicon atom per molecule in such an amount that a ratio of the number of Si—H groups in component (B) to the number of alkenyl groups in component (A) is 1 to 5, and (C) a platinum group metal catalyst in an amount that a platinum group metal amount is 1 to 100 ppm by mass based on a total mass of the composition.