Silicone Adhesive Composition for Optical Clear Adhesives
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Solution Overview
Problem
Conventional silicone adhesives for optical clear adhesives (OCAs) have low adhesive strength, are not suitable for permanent adhesion, and exhibit varying adhesiveness depending on peeling speed, making them unsuitable for applications requiring strong and consistent bonding.
Innovation Solution
A silicone adhesive composition comprising a condensation product of diorganopolysiloxanes with hydroxy or alkoxy groups and organohydrogenpolysiloxanes, along with a platinum group metal catalyst, which provides high adhesive force and excellent release properties from fluorine-containing silicone release compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional silicone adhesive is used for OCA, then good weather resistance and flexibility are achieved, but adhesive strength is low and peeling force varies with peeling speed
Solution Approach 1:
The patent modifies the chemical composition parameters of the silicone adhesive by incorporating specific ratios of vinyl-containing diorganopolysiloxane (0.1-10 mass%), organohydrogenpolysiloxane (1-20 parts by mass per 100 parts polysiloxane), and platinum catalyst (0.01-5 ppm), which changes the curing mechanism and molecular structure to achieve consistent adhesive strength across different peeling speeds
Solution Approach 2:
The patent creates a composite adhesive system by combining multiple polysiloxane components with different functions: base polysiloxane for flexibility, vinyl-containing polysiloxane for crosslinking sites, and organohydrogenpolysiloxane for permanent bonding, resulting in a material that maintains both weather resistance and speed-independent adhesion
2Strength
If acrylic adhesive is used for OCA, then high adhesiveness is achieved, but transparency decreases and yellowing occurs at high temperature
Solution Approach 1:
The patent changes the chemical composition from acrylic-based to specifically formulated silicone-based adhesive with controlled vinyl group content (0.001-0.1 mol/100g) and specific organohydrogenpolysiloxane ratios, which maintains adhesive strength while preserving optical transparency and preventing thermal yellowing
Solution Approach 2:
The patent replaces the conventional acrylic adhesive (which degrades at high temperature) with a thermally stable silicone adhesive system that resists yellowing and maintains performance under thermal stress, extending the service life in high-temperature applications
3Ease of operation
If silicone adhesive with high release property is used, then easy peeling from release liner is achieved, but adhesive strength to adherend decreases
Solution Approach 1:
The patent creates different local properties within the adhesive system: the adhesive layer composition is optimized for strong bonding to the adherend (with specific vinyl and hydrogen polysiloxane ratios for permanent crosslinking), while the interface with the release liner maintains appropriate release properties through controlled surface characteristics and composition gradients
4Strength
If double-sided adhesive tape with substrate is used, then structural support is provided, but total thickness increases which is inconvenient for miniaturization
Solution Approach 1:
The patent removes the substrate component from the double-sided adhesive structure, creating a substrate-free adhesive sheet that provides structural support through its own optimized composition and crosslinking network, thereby eliminating the thickness contribution of the substrate while maintaining mechanical strength
Solution Approach 2:
The patent creates a self-supporting composite adhesive structure using the cured silicone adhesive composition with crosslinked polymer network that provides both adhesive functionality and structural integrity without requiring a separate substrate 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 silicone adhesive composition achieves strong and consistent adhesion independent of peeling speed, with improved release properties and adhesion strength, making it suitable for applications in miniaturized electronic devices and appliances.
Implementation Method 1
a condensation product of a specific diorganopolysiloxane having a hydroxy group and/or an alkoxy group with an organopolysiloxane having an R13SiO0.5 unit and an SiO2 unit and having a hydroxy group and/or an alkoxy group
Implementation Method 2
The silicone adhesive composition achieves strong and consistent adhesion independent of peeling speed
Implementation Method 3
along with a platinum group metal catalyst
Implementation Method 4
excellent release properties from fluorine-containing silicone release compositions
Data Source
AI summary
Provided is a silicone adhesive composition having (A) a condensation product of a linear or branched diorganopolysiloxane having a silicon atom-bonded hydroxy group and/or a silicon atom-bonded alkoxy group having 1 to 10 carbon atoms at a terminal and having no alkenyl group, a linear or branched diorganopolysiloxane having at least two alkenyl groups, and an organopolysiloxane comprising an R13SiO0.5 unit and an SiO2 unit and having a silicon atom-bonded hydroxy group and/or a silicon atom-bonded alkoxy group having 1 to 6 carbon atoms, (B) an organohydrogenpolysiloxane having at least three SiH groups and an average polymerization degree of 80 or less in an amount of 0.1 to 5 parts by mass, relative to 100 parts by mass of component (A), and (C) a platinum group metal catalyst in a catalytic amount.