Multilayer Polyamide Hose for Compressed Air
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Solution Overview
Problem
Existing flexible polyamide hoses for compressed air suffer from mechanical property weaknesses due to insufficient HDPE mechanical resistance and delamination issues caused by plasticizer exudation, leading to inconsistent performance and reduced durability.
Innovation Solution
A multilayer flexible hose design featuring an outer layer of polyamide, an intermediate layer of low modulus polymer, and an inner layer of high modulus polymer, with optional additional layers and binders to enhance adhesion and maintain flexibility, replacing traditional reinforcing braids and crosslinked polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If HDPE layers are used in the hose structure, then adhesion between polyamide layers is improved, but mechanical resistance to bursting is insufficient
Solution Approach 1:
The patent employs a composite structure combining polyamide layers with a polyolefin adhesive layer containing 5-20% crosslinked polyethylene. This composite approach allows the adhesive layer to provide both bonding function and enhanced mechanical strength through crosslinking, resolving the contradiction between adhesion and bursting resistance
Solution Approach 2:
The patent modifies the polyethylene parameters by applying crosslinking through irradiation or chemical agents, transforming it from a simple thermoplastic adhesive into a crosslinked network structure. This parameter change (crosslinking degree) simultaneously improves both adhesion properties and mechanical resistance to bursting
2Ease of operation
If polyamide 6 layers with plasticizer are used, then flexibility is improved, but delamination occurs due to plasticizer exudation
Solution Approach 1:
The patent introduces a polyolefin adhesive layer as an intermediary between the polyamide layers. This intermediate layer prevents direct contact between plasticized polyamide layers, thereby preventing plasticizer exudation and delamination while maintaining the flexibility provided by the plasticized polyamide layers
Solution Approach 2:
The patent extracts the problematic plasticizer-containing polyamide 6 layer and replaces it with a plasticized polyamide 12 layer in contact with compressed air, while using a polyolefin adhesive layer to provide the necessary flexibility and bonding without plasticizer exudation issues
3Strength
If reinforcing braid is added to the hose structure, then mechanical strength is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the reinforcing function with the adhesive layer by incorporating crosslinked polyethylene into the polyolefin adhesive layer. This combination eliminates the need for a separate reinforcing braid, providing mechanical strength while simplifying the manufacturing process through coextrusion of integrated layers
4Strength
If crosslinked polymer layer is added, then mechanical resistance is improved, but number of manufacturing operations increases
Solution Approach 1:
The patent applies crosslinking to the polyethylene component during the adhesive layer formation process itself, rather than as a separate subsequent step. This preliminary action integrates the crosslinking operation into the existing manufacturing workflow, improving mechanical resistance without adding separate manufacturing steps
Solution Approach 2:
The patent combines the adhesive function and the crosslinked reinforcement function into a single polyolefin adhesive layer containing crosslinked polyethylene. This merging eliminates the need for separate crosslinked polymer layers, maintaining mechanical resistance while simplifying manufacturing operations
Data Source
AI summary
The present invention relates to a multilayer hose for compressed air, comprising, in this order, a polyamide outer layer (1); optionally, an intermediate layer (2) of a polymer having a flexural modulus of less than 500 MPa; and an inner layer (3) of a polymer having a flexural modulus greater than 1100 MPa, the inner layer (3) being in contact with the compressed air.