Motor Insulation Sheet Adhesive Composition for Wrinkle Control
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Solution Overview
Problem
Conventional insulation sheets for oil-cooled drive motors in automobiles face issues with thickness accuracy and wrinkle generation in resin film layers, which affect adhesive strength and appearance.
Innovation Solution
An insulation sheet comprising a first resin film layer and a second resin film layer laminated via an adhesive layer containing an acrylic polymer and trimethylolpropane-tolylenediisocyanate trimer adduct, with a gel fraction of 70% or less, is used to suppress wrinkle formation and improve adhesive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a resin film layer is disposed on the surface layer part of the insulation sheet to improve thickness accuracy, then thickness precision is improved, but wrinkles are generated in the resin film layer
Solution Approach 1:
The invention changes the chemical composition parameters of the adhesive layer by specifying it contains an acrylic polymer and a trimethylolpropane-tolylenediisocyanate trimer adduct with a gel fraction of 70% or less. This parameter change in the adhesive layer's molecular structure and crosslinking density prevents wrinkle generation while maintaining the resin film layer's thickness accuracy benefits.
Solution Approach 2:
The invention uses a composite adhesive layer combining an acrylic polymer with a trimethylolpropane-tolylenediisocyanate trimer adduct. This composite material approach creates synergistic effects where the polymer provides flexibility and the isocyanate adduct provides controlled crosslinking, preventing wrinkles while maintaining adhesive strength and thickness precision.
2Strength
If the adhesive layer is thermally cured to improve adhesive strength, then adhesive strength is improved, but wrinkles are generated in the resin film layer
Solution Approach 1:
The invention changes the curing parameter by controlling the gel fraction to 70% or less, which limits the extent of crosslinking. This parameter control allows sufficient adhesive strength development while preventing excessive shrinkage and stress that would cause wrinkles in the resin film layer.
Solution Approach 2:
The invention creates local quality differences in the adhesive layer by using a partially crosslinked structure (gel fraction ≤70%). This localized control of crosslinking density allows the adhesive to maintain strength at the interface while remaining flexible enough to prevent wrinkle formation in the overlaid resin film layer.
3Strength
If a paper-like sheet layer is used in the insulation sheet, then adhesive strength is maintained, but thickness accuracy is insufficient due to large thickness variation
Solution Approach 1:
The invention changes the material parameter from paper-like sheet to resin film layer, which inherently provides better thickness control. The resin film layer's uniform thickness (±5 μm) compensates for the loss of adhesive strength by working synergistically with the specially formulated adhesive layer.
Solution Approach 2:
The invention creates a composite structure combining the resin film layer's thickness precision with the adhesive layer's strength-providing chemistry. This composite approach allows the resin film to provide dimensional stability while the adhesive layer provides bonding strength, achieving both requirements simultaneously.
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 effectively prevents wrinkles and maintains adhesive strength in the resin film layers, ensuring precise thickness and improved durability under heating conditions.
Implementation Method 1
an insulation sheet comprising a first resin film layer and a second resin film layer that are laminated on at least one surface of the first resin film layer via an adhesive layer
Implementation Method 2
a gel fraction of the adhesive layer is 70% or less
Data Source
AI summary
An insulation sheet for a motor according to present invention includes a first resin film layer and a second resin film layer that is laminated on at least one surface of the first resin layer via an adhesive buyer, in which the adhesive layer includes an acrylic polymer and a trimethylolpropane-tolylenediisocyanate trimer adduct, and has a gel fraction of 70% or lead.