Ultra-High Solid Polyurethane Dispersion Adhesive
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Solution Overview
Problem
Current pressure sensitive adhesive compositions lack an optimal balance of shear, tack, and peel properties, and have long drying times, necessitating the development of a composition with improved performance in these areas.
Innovation Solution
A pressure sensitive adhesive composition comprising an ultra-high solid polyurethane dispersion, made from a polyurethane prepolymer and a seed latex, with a chain extender, and optionally including surfactants, thickeners, and fillers, achieving a solid content of at least 60% and viscosity less than 5 Pa.s, which enhances the balance of shear, tack, and peel properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pressure sensitive adhesive compositions are used, then they can provide basic adhesive functionality, but they lack optimal balance of shear, tack, and peel properties and have long drying times
Solution Approach 1:
The patent applies parameter changes by formulating an ultra-high solid polyurethane dispersion with solid content of at least 60% by weight and controlling viscosity to less than 5 Pa.s. This specific composition parameter optimization enables the adhesive to achieve improved balance of shear, tack, and peel properties while reducing drying time through enhanced evaporation kinetics.
Solution Approach 2:
The patent employs composite materials by creating a polyurethane dispersion system that combines polyurethane prepolymer with seed latex particles. This composite structure integrates the adhesive properties of polyurethane with the emulsion stability of latex, achieving superior balance of mechanical properties and reduced drying time compared to conventional single-component adhesives.
2Loss of time
If ultra-high solid polyurethane dispersion with high solid content is used, then drying time is reduced, but viscosity control becomes more challenging
Solution Approach 1:
The patent resolves the viscosity control challenge by precisely optimizing the solid content parameter to at least 60% by weight and controlling the viscosity to less than 5 Pa.s. This parameter optimization allows the ultra-high solid dispersion to maintain processability and proper flow characteristics despite the high solid content that accelerates drying.
3Reliability
If polyurethane dispersion with optimized adhesive properties is formulated, then shear, tack, and peel properties are improved, but the formulation complexity increases
Solution Approach 1:
The patent manages formulation complexity by using a composite polyurethane-latex dispersion system. This approach consolidates multiple adhesive functions into a single integrated formulation, achieving improved shear, tack, and peel properties without proportionally increasing formulation complexity compared to using multiple separate adhesive components.
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 provides improved balance of shear, tack, and peel properties, along with reduced drying time, making it suitable for various applications such as adhesives and coatings.
Implementation Method 1
a first polyurethane prepolymer comprising the reaction product of a polyol and polyisocyanate
Implementation Method 2
a chain extender, wherein the chain extender comprises a diamine
Data Source
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AI summary
The instant invention is a pressure sensitive adhesive composition comprising an ultra-high solid polyurethane dispersion. The ultra-high solid polyurethane dispersion comprises (1) a first component comprising a first polyurethane prepolymer comprising the reaction product of a polyol and polyisocyanate, (2) a second component comprising a media phase selected from the group consisting of a second polyurethane prepolymer emulsion, a low solid content polyurethane dispersion, a seed latex, and combinations thereof; and (3) optionally a chain extender. The ultra-high solid polyurethane dispersion has at least a solid content of at least 60 percent by weight of solid content, based on the total weight of the ultra-high solid polyurethane dispersion, and a viscosity of less than 5000 cps at 20 rpm at 21° C using spindle #4 with Brookfield viscometer.