Epoxide-Amine Crosslinker for Polyacrylate Adhesives
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Solution Overview
Problem
Current thermal crosslinking methods for polyacrylate hotmelts face challenges such as short processing life, inhomogeneous coating, and limited crosslinking depth, particularly when using radiation-based methods or isocyanate crosslinkers, which can lead to rapid and extensive crosslinking, gel formation, and adverse effects on adhesive properties.
Innovation Solution
A crosslinker-accelerator system comprising a specifically substituted amine and an epoxide compound, allowing for controlled thermal crosslinking of polyacrylates, providing a comfortable processing life and rapid secondary crosslinking at low temperatures without the need for actinic irradiation, ensuring uniform and blister-free coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If radiation-based crosslinking methods (UV or EBC) are used, then crosslinking speed is improved, but crosslinking homogeneity deteriorates and processing versatility worsens
Solution Approach 1:
The patent replaces radiation-based crosslinking (UV or electron beam) with thermal crosslinking using a specifically designed crosslinker-accelerator system. This substitution eliminates the penetration depth limitations of radiation methods, enabling homogeneous crosslinking throughout thick adhesive layers while maintaining fast crosslinking speed through the accelerator-catalyzed reaction mechanism.
Solution Approach 2:
The patent changes the crosslinking activation parameter from radiation energy to thermal energy with catalyst acceleration. By using a substantive accelerator that catalyzes the crosslinker reaction at lower temperatures and shorter times, the system achieves both fast crosslinking and homogeneous reaction throughout the adhesive layer, resolving the contradiction between speed and homogeneity.
2Strength
If isocyanate crosslinkers are used for thermal crosslinking, then crosslinking effectiveness is improved, but processing life shortens and gel formation increases
Solution Approach 1:
The patent changes the chemical nature of the crosslinking system from isocyanate-based to epoxide-based with a specific accelerator. This parameter change in the reaction mechanism provides controlled reactivity that maintains long processing life while achieving effective crosslinking, eliminating the rapid gel formation problem associated with isocyanate crosslinkers.
Solution Approach 2:
The patent introduces a specifically designed accelerator as an intermediary that mediates between the crosslinker and the polyacrylate. This accelerator enables controlled crosslinking by catalyzing the epoxide crosslinker reaction, providing both long processing life and effective crosslinking without the harmful side effects of isocyanate systems.
3Strength
If high molecular weight polyacrylates are used, then adhesive strength is improved, but coating processability worsens
Solution Approach 1:
The patent applies preliminary thermal crosslinking to the high molecular weight polyacrylate adhesive before coating. This preliminary crosslinking modifies the polymer structure to improve flow and coating characteristics, making high molecular weight adhesives easier to process while maintaining their inherent strength advantages.
Solution Approach 2:
The patent uses thermal crosslinking as a parameter change to modify the physical state and flow properties of high molecular weight polyacrylates. By controlling the degree of crosslinking, the system achieves optimal balance between coating processability and adhesive strength, enabling easy coating while preserving the strength benefits of high molecular weight polymers.
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 system enables long processing life and rapid crosslinking at room temperature, achieving high elastic fractions and stable adhesive properties, with the ability to crosslink without further thermal energy, resulting in high cohesion and shear strength for polyacrylate compositions.
Implementation Method 1
a crosslinker-accelerator system based on the combination of a substance containing epoxide groups with a specifically substituted amine
Implementation Method 2
the polyacrylate, accordingly, is crosslinked
Data Source
AI summary
Crosslinker-accelerator system for the thermal crosslinking of polyacrylates having functional groups capable of entering into linking reactions with epoxide groups, comprising at leastone substance having at least one epoxide group as crosslinker andat least one substance of the formulaR12N—CR2R3—CR4R5—(CR6R7)n—Xin which the R1 independently represent hydrogen, a substituted or unsubstituted alkyl or cycloalkyl radical or together with the nitrogen atom form a 5-7-membered ring;R2, R3, R4, R5, R6 and R7 independently represent hydrogen or an alkyl radical having 1 to 8 carbon atoms or form a 5-7-membered cycloalkylene group;n=0; andX represents —OH, —OR, —SH, —SR and —PR2, in which R independently represents C1-C18 alkyl radical, C2-C18 alkenyl radical or C2-C18 alkynyl radical, an aryl group or an aliphatic or aromatic heterocycle, as accelerator.