Polyamide-EVOH Metal Laminate for Humid Bonding Stability
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Solution Overview
Problem
Existing laminates for aircraft, automobile, and boat construction suffer from poor tensile strength and fluctuating moisture absorption, leading to unstable bonding properties, especially in humid environments.
Innovation Solution
A laminate comprising a first metal layer, a polymer composition layer made of polyamide with specific copolymers derived from C2-C20 alkenes and acrylic acid derivatives, and optionally a second metal layer, which enhances peeling characteristics and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymer layers (nylon-6,6, polyolefins) are used in laminates, then the laminate structure is simple and easy to manufacture, but the tensile strength is poor and the bonding properties fluctuate in humid environments
Solution Approach 1:
The patent employs a composite polymer layer consisting of polyamide and ethylene-vinyl acetate copolymer in a weight ratio of 95:5 to 50:50. This composite structure combines the high strength and stiffness of polyamide with the flexibility and adhesion properties of EVOH, achieving superior tensile strength and bonding stability while maintaining processability.
Solution Approach 2:
The patent optimizes the weight ratio parameters of the polymer components (polyamide:EVOH from 95:5 to 50:50) and controls the layer thickness (0.02-2 mm) to achieve the desired balance between tensile strength, moisture resistance, and peeling characteristics. By adjusting these parameters, the laminate maintains stable bonding properties in humid environments.
2Strength
If polyamide layers are used to improve strength, then tensile strength increases, but moisture absorption fluctuates leading to unstable bonding properties
Solution Approach 1:
The patent creates a composite system where polyamide provides tensile strength while ethylene-vinyl acetate copolymer contributes moisture resistance and bonding stability. The synergistic combination mitigates the moisture absorption fluctuations inherent in polyamide alone, maintaining stable bonding properties in humid conditions.
Solution Approach 2:
The patent assigns different functional properties to different components: polyamide primarily provides structural strength and stiffness, while the ethylene-vinyl acetate copolymer component provides moisture barrier properties and bonding stability. This functional differentiation allows each material to excel at its specific role, resolving the contradiction between strength and moisture stability.
3Strength
If the polymer layer composition is optimized for strength, then tensile strength improves, but peeling characteristics deteriorate
Solution Approach 1:
The patent utilizes the complementary properties of polyamide (high strength) and ethylene-vinyl acetate copolymer (good peeling characteristics) in a composite structure. The EVOH component's flexibility and adhesion properties enable easy peeling and forming operations while the polyamide matrix maintains high tensile strength, resolving the contradiction between strength and peeling characteristics.
Solution Approach 2:
The patent exploits the different mechanical responses of the two polymer components under different stress conditions: polyamide provides rigidity and strength under tensile loading, while the ethylene-vinyl acetate copolymer provides flexibility and conformability during peeling and forming operations. This dynamic behavior allows the laminate to exhibit both high strength and good peeling characteristics.
Data Source
AI summary
Described herein is a laminate including at least one first layer of at least one first metal and at least one further layer of a polymer composition (PC). Also described herein is a process for producing the laminate.