Molding Packaging Material Adhesive for Deep Forming
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Solution Overview
Problem
Existing molding packaging materials for lithium ion secondary batteries face challenges with delamination between the metal foil layer and the outer resin layer during deep forming, limiting the forming depth and durability under severe environments.
Innovation Solution
A molding packaging material with a heat-resistant resin layer, a metal foil layer, and a two-part curing type polyester polyurethane resin adhesive agent, which includes a specific composition of polyester resin and multifunctional isocyanate, providing high adhesive strength and formability to prevent delamination, along with a chemical conversion coating film for corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If deep forming is performed to heighten the side wall of the case, then the inner volume and formability are improved, but delamination between the metal foil layer and the outer resin layer occurs
Solution Approach 1:
The invention changes the chemical composition parameters of the adhesive agent, specifically using a two-part curing type adhesive with polyol and isocyanate that requires aging at several tens of degrees Celsius for several days to achieve proper curing. This parameter change in the adhesive system enables the laminate to withstand deep forming without delamination
Solution Approach 2:
The invention applies preliminary action by performing aging treatment at several tens of degrees Celsius for several days after bonding the metal foil and resin layer. This preliminary curing process strengthens the adhesive bond before the deep forming operation, preventing delamination during subsequent forming operations
2Reliability
If a two-part curing type adhesive agent is used to enhance adhesive strength, then bonding reliability is improved, but manufacturing time and process complexity increase due to aging requirements
Solution Approach 1:
The invention specifies particular parameter ranges for the polyol and isocyanate components, including the isocyanate index (NCO/OH molar ratio of 0.8-1.5) and molecular weights, which optimize the curing characteristics to achieve strong adhesion while reducing the required aging time compared to conventional adhesives
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 enables deeper forming without delamination, ensuring the heat-resistant resin layer remains intact, even under severe conditions, and provides a corrosion-resistant battery case with improved formability and durability.
Implementation Method 1
a first adhesive agent layer arranged between the heat resistant resin layer and the metal foil layer, wherein the first adhesive agent layer is constituted by an adhesive agent containing a two-part curing type polyester polyurethane resin made of a polyester resin as a main ingredient and a multifunctional isocyanate compound as a curing agent
Implementation Method 2
a two-part curing type polyester polyurethane resin made of a polyester resin as a main ingredient and a multifunctional isocyanate compound as a curing agent
Implementation Method 3
the adhesive agent containing a two-part curing type polyester polyurethane resin made of a polyester resin as a main ingredient and a multifunctional isocyanate compound as a curing agent
Implementation Method 4
along with a chemical conversion coating film for corrosion resistance
Data Source
AI summary
A molding packaging material includes a heat resistant resin layer as an outer layer, a metal foil layer, and a first adhesive agent layer arranged there between. The first adhesive agent layer is constituted by an adhesive agent containing a two-part curing type polyester polyurethane resin made of a polyester resin as a main ingredient and a multifunctional isocyanate compound as a curing agent. The polyester resin is made from dicarboxylic acid and dialcohol, the dicarboxylic acid contains aliphatic carboxylic acid whose number of methylene of a methylene chain is an even number and aromatic carboxylic acid, and a content rate of the aromatic carboxylic acid to a total amount of aliphatic carboxylic acid and aromatic carboxylic acid is 40 to 80 mol %. The polyester resin is 8,000 to 25,000 in number average molecular weight (Mn) and 15,000 to 50,000 in weight average molecular weight (Mw), and a ratio thereof (Mw/Mn) is 1.3 to 2.5.