Type C A/C Hose With Direct-Bond Barrier for Low Refrigerant Permeation
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Solution Overview
Problem
Existing automotive refrigerant hoses face issues with permeability to refrigerants and require adhesives for bonding thermoplastic and elastomeric layers, leading to spotty adhesion and increased extractible content.
Innovation Solution
A novel Type C air conditioning hose design featuring a blended elastomer layer that directly bonds to a thermoplastic barrier without adhesives, using a composition of ethylene propylene diene monomer (EPDM) and chloroprene rubber, phenylenedimaleimide, and maleated compounds, allowing for strong adhesion and low permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermoplastic layer is incorporated to decrease permeability, then permeation resistance is improved, but adhesion becomes spotty and extractible content increases
Solution Approach 1:
The patent uses a primer layer as an intermediary substance between the thermoplastic barrier layer and the elastomeric tube layer. This primer promotes adhesion without requiring additional adhesives, thereby maintaining low extractible content while ensuring proper bonding between the thermoplastic and elastomeric layers.
Solution Approach 2:
The patent modifies the chemical composition and surface properties of the thermoplastic barrier layer to enhance its adhesion characteristics. By changing the parameters of the thermoplastic material itself, the patent achieves both low permeation and reduced extractible content without compromising bonding quality.
2Strength
If adhesive is used to bond thermoplastic layer to elastomeric layer, then adhesion strength is improved, but extractible content increases
Solution Approach 1:
The patent replaces traditional adhesives with a primer layer that serves as a bonding intermediary. This primer is specifically formulated to promote adhesion between the thermoplastic barrier layer and elastomeric tube layer without contributing to extractible content, thus maintaining both strong bonding and low extractible content.
Solution Approach 2:
The patent extracts and eliminates the adhesive component from the hose construction by using a primer-based bonding system instead. This removal of adhesive eliminates the source of extractible content while maintaining adhesion strength through the primer's bonding properties.
3Reliability
If Type E veneer hose design is used, then permeation is reduced, but flexibility is limited and cost increases
Solution Approach 1:
The patent applies the thermoplastic barrier layer locally as a veneer coating on the inner surface of the elastomeric tube, rather than using a thick multi-layer construction. This localized application provides sufficient permeation resistance while preserving the flexibility of the underlying elastomeric material.
Solution Approach 2:
The patent creates a composite structure combining a thermoplastic barrier layer with an elastomeric tube layer, where each material contributes its superior properties. The thermoplastic provides low permeation while the elastomer provides flexibility, achieving a balance that neither material could provide alone.
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 hose exhibits very low permeation to refrigerants R1234yf and R134a, with minimal extractible content and improved flexibility, meeting SAE J2064 and J3062 standards.
Implementation Method 1
The refrigerant hose includes an elastomeric tube layer and an elastomeric backing layer that are directly bonded to an inner surface of the thermoplastic barrier layer
Implementation Method 2
Incorporation of a thermoplastic layer may help decrease permeability
Data Source
Figure 1~2B
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AI summary
An improved Type C air conditioning hose is provided that meets or exceeds SAE J2064 and J3062 requirements, offers good flexibility and fracture resistance, and exhibits improved permeation ratings for refrigerants including R134a and R1234yf. The multilayer type C barrier air conditioning hose includes a novel inner elastomeric tube layer capable of direct bonding to plastic without an intervening adhesive.