Curable Adhesive Precursor for Electric Motor Steel Lamination
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Solution Overview
Problem
Existing adhesive compositions for laminating steel sheets in electric motors face challenges such as low adhesive strength at high temperatures, tendency of curing failure at the edges, and long curing times, which hinder efficient mass production and performance.
Innovation Solution
A curable precursor adhesive composition comprising a radically (co)polymerizable compound, a vanadium compound, a beta-dicarbonyl compound, and a quaternary ammonium halide, which allows for rapid handling strength and high adhesive strength without the need for additional initiators or mixing steps, and can be cured at room temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If anaerobic adhesives comprising an accelerator are used to achieve fast curing speed, then curing speed is improved, but adhesive strength at high temperature deteriorates and curing failure occurs at edges
Solution Approach 1:
The patent changes the chemical parameters of the adhesive system by using a one-part composition with a specific initiator system (organometallic compound + beta-diketone) that enables fast curing at room temperature without the need for accelerators. This parameter change allows achieving both fast curing speed and high temperature durability simultaneously, resolving the contradiction between curing speed and high-temperature strength.
2Strength
If one-part thermosetting epoxy adhesive is used to achieve high adhesive strength, then adhesive strength is improved, but a heating process is required which increases process complexity
Solution Approach 1:
The patent employs a self-curing mechanism where the organometallic compound and beta-diketone components automatically react at room temperature to generate radicals that initiate polymerization. This self-service curing process eliminates the need for external heating equipment or complex curing cycles, thereby reducing process complexity while maintaining high adhesive strength.
3Strength
If two-part epoxy or acrylic adhesives are used to achieve high adhesive strength, then adhesive strength is improved, but a mixing step is required leading to long time to achieve handling strength
Solution Approach 1:
The patent segments the adhesive system into two separate parts that are mixed only at the moment of application: Part A containing the radically polymerizable compound and organometallic compound, and Part B containing the beta-diketone. This segmentation allows the components to remain stable separately while enabling fast curing upon mixing, achieving high adhesive strength within minutes without requiring prolonged mixing or waiting periods.
4Strength
If a primer layer is used for curing the curable composition, then adhesion to substrate is improved, but process time increases due to drying requirement
Solution Approach 1:
The patent extracts and eliminates the primer layer step from the traditional curing process. The adhesive composition is formulated to directly bond to the substrate without requiring a separate primer coating and drying step. The organometallic compound and beta-diketone system provides sufficient adhesion promotion within the adhesive matrix itself, removing the time-consuming primer application and drying process while maintaining strong substrate adhesion.
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 curable precursor achieves fast curing with good handling strength within 30 seconds and high adhesive strength of 2 MPa or higher at 180 °C after 48 hours, while maintaining thin bond-line thickness and high-temperature durability, suitable for cost-effective mass production of electric motor cores.
Implementation Method 1
an air-activatable initiator which generates a peroxide in situ. The initiator comprises a beta-dicarbonyl compound and a vanadium compound
Implementation Method 2
a curable precursor of an adhesive composition comprising a radically (co)polymerizable compound, a vanadium compound, a beta-dicarbonyl compound, and a quaternary ammonium halide
Data Source
AI summary
The present disclosure relates to a curable precursor of an adhesive composition, wherein the curable precursor comprises (a) a radically (co)polymerizable compound, (b) a vanadium compound, (c) a beta-dicarbonyl compound, and (d) a quaternary ammonium halide. The present disclosure further relates to a method of curing the said curable precursor.