Polyamide-Polyolefin Laminate for Burst Strength and Cold Impact
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Solution Overview
Problem
Current piping systems for automotive applications, particularly those using polyamide-based resins, face challenges in achieving high temperature resistance, mechanical strength, and barrier properties against chemical solutions like LLC and refrigerants, especially when the polyolefin layer thickness is increased, leading to issues with bursting pressure and low temperature impact resistance.
Innovation Solution
A laminate structure comprising an aliphatic polyamide composition and a modified polyolefin with specific mechanical properties, where the modified polyolefin includes units derived from α-olefins and unsaturated compounds with functional groups, enhancing low temperature impact resistance and bursting pressure strength even with a thick polyolefin layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the polyolefin layer is increased to improve chemical solution barrier properties and long-term resistance, then the barrier property and chemical resistance are improved, but the bursting pressure strength and low temperature impact resistance deteriorate
Solution Approach 1:
The invention changes the physical and chemical parameters of the polyolefin layer by introducing specific additives (antioxidants, UV absorbers, processing aids) and controlling molecular weight and composition. This allows the polyolefin layer to achieve both thick-layer chemical resistance and maintained mechanical strength through optimized material parameters rather than simply increasing thickness
Solution Approach 2:
The invention creates a composite material system where the polyolefin layer is enhanced with multiple functional additives and potentially combined with other polymer layers. This composite approach allows the polyolefin to provide chemical barrier properties while the additive system maintains or enhances mechanical properties like bursting pressure strength
2Reliability
If the thickness of the polyolefin layer is increased to improve chemical resistance, then the long-term resistance to chemical solutions is improved, but the low temperature impact resistance deteriorates
Solution Approach 1:
The invention modifies the polyolefin's physical parameters through additive incorporation and compositional control to maintain flexibility and impact resistance at low temperatures even when the layer is thick. The additives prevent embrittlement and maintain ductility across temperature ranges
Solution Approach 2:
The invention applies different functional properties to different aspects of the polyolefin layer - the base polyolefin provides chemical resistance while the additive system specifically addresses low-temperature mechanical properties. This local optimization allows simultaneous achievement of chemical barrier function and low-temperature toughness
3Strength
If a single layer tube using polyamide-based resin is used to achieve mechanical strength and flexibility, then the strength and flexibility are improved, but the barrier property to chemical solutions and long-term durability deteriorate
Solution Approach 1:
The invention divides the tube structure into multiple functional layers: a polyamide-based outer layer providing mechanical strength and flexibility, and a polyolefin inner layer providing chemical solution barrier properties. This segmentation allows each layer to specialize in its optimal function without compromising the other
Solution Approach 2:
The invention creates a composite tube structure combining polyamide and polyolefin materials, each contributing their superior properties. The polyamide provides tensile strength and flexibility while the polyolefin provides chemical resistance, achieving overall superior performance to either material alone
4Reliability
If fluorine-based resins are used to achieve excellent chemical solution resistance and water vapor barrier property, then the chemical resistance and barrier property are improved, but the specific gravity and cost increase
Solution Approach 1:
The invention replaces expensive fluorine-based resins with a more economical polyolefin-based composition that achieves comparable chemical solution resistance. The polyolefin system provides cost-effective alternative with lower specific gravity while maintaining the required barrier properties through optimized formulation
Data Source
AI summary
Provided is a laminate that has excellent low-temperature impact resistance and bursting pressure strength at high temperatures despite having a thick modified polyolefin layer. The laminate has two or more layers including an (a) layer and a (b) layer, the (a) layer includes an aliphatic polyamide composition (A), and the (b) layer includes a modified polyolefin (B). The modified polyolefin (B) includes a unit derived from a monomer based on an α-olefin having 2-10 carbon atoms, and a unit derived from an unsaturated compound having at least one functional group selected from the group consisting of: unsaturated compounds having at least one group selected from the group consisting of a carboxyl group, a hydroxyl group, an epoxy group, an amino group, an amide group, an imide group, a nitrile group, a thiol group, and an isocyanate group; and derivatives of unsaturated compounds having a carboxyl group. The Shore hardness (D scale) of the modified polyolefin (B) as measured according to ASTM D2240 is 30-61.