Modified Olefin Adhesive Composition for Battery Packaging
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Solution Overview
Problem
Adhesive layers formed from existing adhesives lack sufficient bond strength to substrates like aluminum foil or polypropylene films, particularly when cured at low temperatures, leading to reduced durability and chemical resistance.
Innovation Solution
A composition comprising a modified olefin polymer, a crosslinking agent, and a catalyst with a pKa of 11 or more, along with a hydrocarbon synthetic oil, which forms an adhesive layer with excellent bond strength and chemical resistance, even under low-temperature aging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional adhesives containing modified olefin resin and epoxy compound are used, then the adhesive layer can be formed, but the bond strength to substrate and adherend is insufficient, particularly under low-temperature aging conditions
Solution Approach 1:
The patent changes the chemical parameters of the adhesive system by introducing a catalyst with pKa≥11 (such as DBU or phosphazene base) to accelerate the crosslinking reaction. This parameter change enables the adhesive to achieve sufficient bond strength and crosslinking degree even at low curing temperatures (80°C or lower), resolving the contradiction between forming an adhesive layer and achieving adequate bond strength under low-temperature aging conditions.
Solution Approach 2:
The patent creates a composite adhesive system combining modified olefin polymer (with carboxyl or acid anhydride groups), epoxy crosslinking agent, and strong base catalyst. This composite material formulation enables simultaneous achievement of good adhesion to polypropylene substrates, sufficient crosslinking density, and excellent bond strength even under low-temperature curing conditions, which conventional single-component adhesives cannot achieve.
2Use of energy by stationary object
If the adhesive is cured at low temperature, then the processing cost and energy consumption are reduced, but the bond strength and chemical resistance of the adhesive layer deteriorate
Solution Approach 1:
The patent introduces a catalyst with high basicity (pKa≥11) as a key parameter change that dramatically accelerates the crosslinking reaction kinetics. This allows the curing process to proceed efficiently at low temperatures (reducing energy consumption) while still achieving the necessary crosslinking density and bond strength, thus resolving the contradiction between low curing energy and sufficient bond strength.
Solution Approach 2:
The patent replaces thermal energy activation with chemical catalysis activation. Instead of relying solely on high temperature to drive the crosslinking reaction, the strong base catalyst (chemical mechanism) substitutes for thermal activation (physical mechanism), enabling low-temperature curing while maintaining adequate crosslinking degree and bond strength.
3Ease of manufacture
If the adhesive layer is formed with conventional formulations, then the application process is simple, but the chemical resistance and long-term durability are insufficient
Solution Approach 1:
The patent develops a composite adhesive formulation that maintains the simplicity of conventional two-component mixing while incorporating modified olefin polymer with reactive groups (carboxyl or acid anhydride), epoxy crosslinking agent, and strong base catalyst. This composite system achieves excellent chemical resistance and long-term durability through effective crosslinking, without significantly complicating the manufacturing process.
Solution Approach 2:
The patent modifies the chemical composition parameters by selecting specific catalysts with pKa≥11 and controlling their concentration (0.1-10 parts by weight per 100 parts modified olefin polymer). This parameter optimization ensures complete crosslinking reaction for superior chemical resistance while maintaining a straightforward manufacturing process that only requires mixing and low-temperature curing.
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 provides a strong and durable adhesive layer that effectively bonds aluminum foil and polypropylene films, maintaining bond strength and chemical resistance over time, suitable for use in battery case packaging materials and lithium ion secondary batteries.
Implementation Method 1
a catalyst (C) having a pKa of 11 or more
Implementation Method 2
a crosslinking agent (B) comprising at least one of an epoxy compound and an oxazoline compound
Data Source
Figure 1
AI summary
The present invention relates to a composition, a laminate, a packaging material, a battery case packaging material, and a battery, and the composition includes: a modified olefin polymer (A) that is a modified olefin polymer, the modified olefin polymer being a polymer (a) of a C2 to C20 α-olefin modified by a monomer (b) having a functional group reactive with an epoxy group or an oxazoline group; a crosslinking agent (B) including at least one of an epoxy compound and an oxazoline compound; and a catalyst (C) having a pKa of 11 or more, the modified olefin polymer (A) satisfying the following requirements (i) and (ii): Requirement (i): the polymer (a) contains a structural unit derived from a C4 to C20 α-olefin, and Requirement (ii): a heat of fusion of the polymer (A), as measured according to JIS K7122, is 0 to 50 J/g.