Acrylic Pressure Sensitive Adhesive Formulation Without Isocyanates
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Solution Overview
Problem
Current acrylic-based pressure sensitive adhesive formulations rely on isocyanate cross-linking agents, which are toxic, expensive, and lack stability, restricting the types of acrylic bases that can be used and requiring on-site mixing, making them unsuitable for long-term storage and use in applications like screen protection.
Innovation Solution
A self-wetting adhesive formulation using pre-polymerized cross-linkable acrylic-based pressure sensitive adhesives with alternative cross-linking agents such as metal chelates, silanes, and polyols, eliminating isocyanates and allowing for longer work life, lower toxicity, and shelf-stable ready-to-use products with improved removability and expanded acrylic polymer options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isocyanate cross-linking agents are used in acrylic-based pressure sensitive adhesive formulations, then cross-linking and adhesion are achieved, but toxicity increases, cost increases, and stability at ambient conditions deteriorates
Solution Approach 1:
The patent removes isocyanate cross-linking agents from the adhesive formulation entirely, extracting the harmful component while maintaining the cross-linking function through alternative mechanisms (silane cross-linking or hydrogen bonding) that do not require toxic isocyanates
Solution Approach 2:
The patent introduces silane cross-linking agents as intermediaries to achieve cross-linking without isocyanates. The silanes serve as a mediator that provides the necessary cross-linking functionality while being non-toxic and stable at ambient conditions
2Reliability
If isocyanate cross-linking agents are used in acrylic-based pressure sensitive adhesive formulations, then cross-linking is achieved, but cost increases
Solution Approach 1:
The patent employs silane cross-linking agents and other alternative cross-linking mechanisms that are less expensive than isocyanates, making the adhesive formulation more cost-effective while maintaining performance
3Reliability
If isocyanate cross-linking agents are used in acrylic-based pressure sensitive adhesive formulations, then cross-linking is achieved, but stability at ambient conditions deteriorates, requiring on-site mixing
Solution Approach 1:
The patent pre-mixes all adhesive components including the silane cross-linking agent in a stable formulation that can be stored at ambient conditions. The cross-linking action is controlled to occur at the appropriate time through humidity activation or thermal curing, eliminating the need for on-site mixing
4Reliability
If isocyanate cross-linking agents are used in acrylic-based pressure sensitive adhesive formulations, then cross-linking is achieved, but the types of acrylic base polymers that can be used are restricted
Solution Approach 1:
The patent uses silane cross-linking agents that can work with a broader range of acrylic base polymers including functional acrylics beyond just hydroxyl-functional acrylics. The silane cross-linking mechanism provides universal compatibility with multiple polymer types, increasing formulation flexibility
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 formulation achieves low peel strength, self-wetting properties, and easy removability without residue, enabling cost-effective, environmentally friendly, and stable adhesive solutions for display screens and other devices, with a potential pot life of up to one year.
Implementation Method 1
The adhesive formulation, when cured, is self-wetting and has a peel strength less than 20 oz/in
Data Source
AI summary
An adhesive formulation is disclosed that includes (a) a pre-polymerized cross-linkable non-water soluble acrylic based pressure sensitive adhesive, (b) a cross-linking agent selected from the group consisting of metal chelates, silanes, epoxy-functional compounds, aziridine compounds, multifunctional amines, alkyl halide compounds, multifunctional acids, multifunctional mercaptans, multifunctional epoxy compounds, polyols in the presence of a catalyst, and combinations thereof and (c) a polyol having a weight average molecular weight in the range from 1,000 g/mol to 10,000 g/mol. When cured, the adhesive formulation is self-wetting and has a peel strength less than 20 oz/in.