Hybrid Polysiloxane Block Copolymer Adhesive for Low Energy Surfaces
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Solution Overview
Problem
Existing silicone pressure-sensitive adhesives (PSAs) face challenges in achieving high adhesion to low surface energy surfaces, solvent-based processing, and high volatile organic compound (VOC) content, which limits their environmental sustainability and processing costs.
Innovation Solution
A radiation-crosslinked blend of nonfunctionalized polysiloxane and styrenic block copolymers, combined with tackifiers, is used to create a hybrid PSA that eliminates the need for solvents and complex condensation reactions, enabling robust adhesion to various substrates and reducing VOC emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional silicone PSA is produced by bodying process with functionalized silicone gum and MQ resin, then adhesion to low surface energy surfaces is improved, but VOC content increases and processing complexity increases
Solution Approach 1:
The invention changes the chemical parameters by using nonfunctionalized polysiloxane instead of functionalized silicone gum, eliminating the condensation reaction and catalyst requirements. This parameter change maintains adhesion performance while eliminating VOC emissions from solvents and catalysts
Solution Approach 2:
The invention creates a composite adhesive system combining nonfunctionalized polysiloxane with styrenic block copolymer and silicate-based tackifier. This composite approach achieves both adhesion to low surface energy surfaces and elimination of VOC content by using a multi-component system that doesn't require solvent-based processing
2Reliability
If traditional silicone PSA uses functionalized silicone gum and MQ resin with condensation reaction, then adhesion performance is improved, but manufacturing complexity increases due to catalysts and solvent coating processes
Solution Approach 1:
The invention extracts and eliminates the problematic components from the traditional bodying process - specifically removing the need for catalysts, solvents, and complex condensation reactions. The nonfunctionalized polysiloxane formulation allows direct use without these additional components
Solution Approach 2:
The invention replaces the chemical condensation reaction system with a physical blending and radiation curing system. Instead of using catalysts and solvents in a complex chemical reaction, the adhesive is formed by blending components and then crosslinking through electron beam or UV radiation
3Ease of operation
If solvent-based coating processes are used for traditional silicone PSA, then ease of application is improved, but environmental sustainability worsens due to high VOC emissions
Solution Approach 1:
The invention converts the traditional approach that relied on solvents for ease of application into a solvent-free system that uses radiation curing. The harm of VOC emissions is eliminated while maintaining ease of application through the same coating processes, now without harmful byproducts
4Object-generated harmful factors
If nonfunctionalized polysiloxane is used instead of functionalized silicone gum, then VOC content is reduced, but adhesion to low surface energy surfaces may be compromised
Solution Approach 1:
The invention creates a composite system where nonfunctionalized polysiloxane is combined with styrenic block copolymer and silicate-based tackifier. This composite formulation compensates for the lack of functional groups in nonfunctionalized polysiloxane while maintaining adhesion to low surface energy surfaces and eliminating VOC content
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 hybrid PSA exhibits excellent adhesion and shear resistance, simplifies processing, and reduces environmental impact by minimizing solvent use and VOC content, while maintaining performance across a wide range of substrates and temperatures.
Implementation Method 1
The blends are prepared by melt-processing, and pressed or extruded films thereof are crosslinked by electron beam or UV radiation
Implementation Method 2
The blends are prepared by melt-processing, and pressed or extruded films thereof are crosslinked by electron beam or UV radiation
Data Source
Figure 1~2
AI summary
There is provided a pressure sensitive adhesive demonstrating adhesion to low energy surfaces which is a radiation-crosslinked mixture of a first component comprising a blend of a nonfunctionalized polysiloxane and a silicate-based tackifier; and a second component comprising a blend of a styrenic block copolymer and a tackifier compatible with the styrenic block copolymer. In some embodiments the weight ratio of nonfunctionalized polysiloxane to styrenic block copolymer.in the mixture is between 0.20 and 1.15. In some embodiments the tackifier compatible with the styrenic block copolymer is a blend of hydrogenated hydrocarbon resin tackifier and terpene-based tackifier in a weight ratio of greater than 0.75 hydrogenated hydrocarbon resin tackifier to terpene-based tackifier.