Multilayer Polyester Film for Metal Laminate Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multilayer polyester films used in laminates for food and beverage containers face issues with adhesion, feathering, migration, corrosion resistance, heat treatment resistance, tensile strength, and formability, while organic solvent-based coatings pose environmental and toxicological concerns.
Innovation Solution
A multilayer biaxially oriented polyester film with specific layer compositions and combinations, including copolyesters with Ethylene Glycol and CycloHexaneDiMethanol units, and filler particles, enhances adhesion, reduces feathering, and improves resistance to acid corrosion and heat treatment, while avoiding organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic solvent-based coating compositions are used, then adhesion and chemical resistance are improved, but environmental and toxicological aspects deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by replacing organic solvent-based formulations with water-based or solvent-free polyester coatings. This parameter change maintains adhesion and chemical resistance while eliminating harmful organic solvents, thereby resolving the contradiction between reliability and environmental impact.
Solution Approach 2:
The patent employs composite material structures with multiple polyester layers having different compositions and properties. The coating comprises a first layer with specific polyester materials for adhesion to metal, and a second layer with crystallizable polyester for barrier properties. This composite structure achieves the required performance without organic solvents.
2Strength
If the film provides high adhesion to metal substrates, then bonding strength is improved, but feathering increases
Solution Approach 1:
The patent applies local quality by creating different layer structures with specific properties in different locations. The first layer (5-40% thickness) is optimized for adhesion to the metal substrate, while the second layer (60-95% thickness) provides feathering resistance. This localized optimization resolves the contradiction between adhesion strength and feathering control.
Solution Approach 2:
The patent uses composite polyester materials with specific compositions in each layer. The first layer comprises polyester materials selected from specific groups for metal bonding, while the second layer uses crystallizable polyester for dimensional stability and feathering resistance. This composite approach simultaneously achieves high adhesion and low feathering.
3Strength
If the film uses crystallizable polyester layers, then mechanical strength is improved, but heat treatment resistance deteriorates
Solution Approach 1:
The patent carefully controls the crystallinity parameters and melting temperature ranges of the polyester layers. The second layer uses crystallizable polyester with specific melting temperature characteristics that allow it to provide mechanical strength while maintaining stability during heat treatment processes. This parameter optimization resolves the contradiction between strength and heat resistance.
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 film provides improved adhesion to metal substrates, reduces feathering, and maintains integrity during heat treatment, ensuring high tensile strength and formability, with reduced migration and environmental impact.
Implementation Method 1
a first adhesive and amorphous layer adjacent the metal sheet comprising one or more polyester materials
Implementation Method 2
resistance to corrosion, especially acid corrosion
Implementation Method 3
heat-bonded to at least one major surface of the metal sheet
Data Source
AI summary
A multilayer transparent film with successively: an amorphous layer C of copolyester PET-G-which the diol units include Ethylene Glycol -EG- units and CycloHexaneDiMethanol -CHDM- units; a crystalline/crystallizable layer B with: a copolyester PET-X which the diol units include Ethylene Glycol -EG- units and which the acid units include Terephtalic Acid -TA- units and units of at least one Dicarboxylic Acid Different From Terephtalic Acid [DADFTA units], the DADFTA units being chosen in the group consisting of Isophtalic Acid -IA-units, Sebacic Acid -SA-units, Adipic Acid -AA-units, and mixtures thereof; and possibly a polyester PolyEthyleneTerephtalate PET; optionally a layer A, identical or different from the layer B, wherein the concentration of the CHDM units in the layer C is between 15 and 34 mol % and the melting temperature of layer B is between 180 and 245° C. Also a manufacturing method of the film and its applications for the manufacture of containers.