Amorphous Poly-alpha-olefins for Hot-melt Adhesive Sprayability
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Solution Overview
Problem
Amorphous poly-alpha-olefins (APAOs) used in hotmelt adhesives require higher application temperatures and suffer from poor sprayability, leading to inefficiencies and increased energy consumption, whereas SBS/SIS-based systems have lower application temperatures but come with resin content and odor issues.
Innovation Solution
Developing amorphous poly-alpha-olefins with specific viscosity and molecular distribution characteristics, achieved through free-radical degradation, allowing for lower application temperatures and improved sprayability without the need for additional resins or oils, thus enhancing the uniformity and stability of the adhesive composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If amorphous poly-alpha-olefins (APAOs) are used in hotmelt adhesives, then resin content and odor nuisance are reduced, but application temperature increases to >140°C and sprayability deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight distribution parameters (Mw/Mn ratio of 3-8, Mz/Mw quotient ≤3.0, Mz/Mn quotient <21.0) and viscosity (≤5000 mPa·s at 190°C) of the APAO polymer. These parameter optimizations enable the polymer to achieve both low odor nuisance and reduced application temperature, resolving the technical contradiction between these two features.
2Quantity of substance
If amorphous poly-alpha-olefins (APAOs) are used in hotmelt adhesives, then resin content is reduced, but sprayability and uniformity of spraying result deteriorate
Solution Approach 1:
The patent resolves this contradiction by optimizing the molecular weight distribution parameters of the APAO, specifically setting Mw/Mn between 3-8, Mz/Mw ≤3.0, and Mz/Mn <21.0. These parameter changes improve sprayability and uniformity while maintaining low resin content formulations.
3Temperature
If SBS/SIS-based systems are used, then application temperature is reduced to about 120°C and spray uniformity is improved, but resin content increases to more than 40% by weight and odor nuisance increases
Solution Approach 1:
The patent achieves lower application temperatures with reduced resin content by optimizing the APAO's molecular weight distribution (Mw/Mn of 3-8, Mz/Mw ≤3.0, Mz/Mn <21.0) and viscosity (≤5000 mPa·s at 190°C). This allows the polymer to flow and spray effectively at lower temperatures without requiring high resin formulations.
4Ease of operation
If SBS/SIS-based systems are used, then sprayability is improved, but odor nuisance and resin content increase
Solution Approach 1:
The patent improves sprayability while reducing odor nuisance by optimizing the APAO's molecular weight distribution parameters (Mw/Mn of 3-8, Mz/Mw ≤3.0, Mz/Mn <21.0) and viscosity (≤5000 mPa·s at 190°C). These parameter changes enable good spray performance with APAO-based systems without requiring styrene-based SBS/SIS materials that cause odor issues.
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 solution reduces spray temperatures to 100° C. to 140° C., improves spray uniformity, increases process stability, and allows for higher polymer content in formulations, reducing energy usage and substrate stress while minimizing odor nuisance and 'angel hair' formation.
Implementation Method 1
a process for producing degraded amorphous poly-alpha-olefins, especially the amorphous poly-alpha-olefins according to the invention
Data Source
AI summary
The invention relates to amorphous poly-alpha-olefins, which are characterized in that said amorphous poly-alpha-olefins have a viscosity at 190° C. of less than 5000 mPas, a molar mass distribution (Mw/Mn) of 3 to 8, a quotient Mz/Mw of less than or equal to 3.0 and a quotient Mz/Mn of less than 21.0. The invention further relates to a method for producing degraded amorphous poly-alpha-olefins, in particular the amorphous poly-alpha-olefins according to the invention, and to the use of the amorphous polyalpha-olefins according to the invention or produced according to the invention in hot-melt adhesive compositions.