Polyurethane Adhesive Composition for Lithium-Ion Battery Lamination
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Solution Overview
Problem
Existing lamination adhesive compositions used for lithium-ion battery (LIB) applications fail to achieve sufficient bond strength, moldability, and heat resistance, particularly in deep draw and high-temperature applications.
Innovation Solution
A two-component (2K) solvent-based polyurethane adhesive composition is developed, comprising an isocyanate group-containing component and a polyol component with a high molecular weight polyester polyol and a phosphate ester polyol, where the phosphate ester polyol is present in the range of 0.3% to 2%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional lamination adhesive compositions are used, then the adhesive can be applied to substrates, but the bond strength at high temperature (120°C) is insufficient (cannot achieve >2 N/15mm)
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by incorporating specific polyols (polyester polyol with Mn≥10,000, phosphate ester polyol at 5-20 phr, and hydroxyl-functional silicone oil at 3-10 phr) and controlling the NCO:OH ratio between 0.8-1.2. These parameter changes enable the adhesive to achieve bond strength >2 N/15mm at 120°C while maintaining heat resistance.
Solution Approach 2:
The patent creates a composite adhesive system by combining multiple polyol types (polyester polyol, phosphate ester polyol, and hydroxyl-functional silicone oil) with isocyanate compounds. This composite material approach synergistically improves both bond strength and heat resistance, resolving the contradiction between these two properties.
2Shape
If conventional adhesive compositions are used, then the adhesive can be applied, but moldability in deep draw applications is insufficient
Solution Approach 1:
The patent modifies the adhesive's rheological parameters by adding hydroxyl-functional silicone oil (3-10 phr) which improves flow characteristics and moldability during deep draw. The viscosity and curing behavior are optimized through controlled NCO:OH ratio (0.8-1.2) and selection of high molecular weight polyester polyol (Mn≥10,000), enabling both good moldability and deep draw reliability.
3Strength
If the adhesive is designed for high bond strength, then bonding performance improves, but the formulation complexity increases
Solution Approach 1:
The patent achieves high bond strength through precise control of key formulation parameters: NCO:OH ratio (0.8-1.2), phosphate ester polyol content (5-20 phr), and hydroxyl-functional silicone oil content (3-10 phr). This parameter-based approach provides a systematic method to achieve consistent performance without excessive formulation complexity.
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 adhesive composition exhibits enhanced bond strength, moldability, and heat resistance, enabling successful deep draw and high-temperature applications, such as in the manufacturing of foil-based composite structures for LIB packaging.
Implementation Method 1
When the two components are mixed, the polyisocyanates and polyols react to form a cured polyurethane adhesive; and the reaction can form a strong adhesive bond to many types of substrates
Implementation Method 2
heating the combined first substrate, second substrate, and the adhesive of step (I) to a temperature sufficient to cure the adhesive composition
Data Source
Figure 1
AI summary
A polyurethane adhesive composition, such as a two-component polyurethane adhesive, including (A)at least one isocyanate group-containing component including at least one isocyanate group-containing compound; and (B) at least one polyol component including: (Bi) at least one polyester polyol compound; and(Bii) at least one phosphate ester polyol compound; and aprocess for making the above composition.