Type C AC Hose Structure With Direct-Bond Barrier Layers
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Solution Overview
Problem
Existing Type C and Type E refrigerant hoses face challenges with permeation and extractible content, particularly due to the need for adhesives to bond elastomeric layers to thermoplastic layers, which can result in spotty adhesion and higher costs.
Innovation Solution
A novel Type C air conditioning hose design featuring a blended elastomer layer that directly bonds to a thermoplastic barrier material without the use of adhesives, achieving very low permeation and extractible content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to bond elastomeric layer to thermoplastic layer, then bonding strength is improved, but extractible content increases and adhesion becomes spotty
Solution Approach 1:
The invention removes the adhesive layer from the hose structure, eliminating the source of extractible content entirely. The elastomeric barrier tube is designed to bond directly to the thermoplastic barrier layer through molecular-level adhesion, achieving strong bonding without any adhesive material that could migrate or degrade.
Solution Approach 2:
The invention uses a composite structure where an elastomeric barrier tube with specific molecular structure (incorporating polar groups and functional additives) is directly bonded to a thermoplastic barrier layer. This composite design enables direct adhesion between dissimilar materials without requiring a separate adhesive layer.
2Reliability
If thermoplastic layer is incorporated to decrease permeability, then permeation resistance is improved, but flexibility deteriorates
Solution Approach 1:
The invention applies different material properties to different layers: the thermoplastic barrier layer provides high permeation resistance with thick continuous structure, while the elastomeric barrier tube provides flexibility and toughness. This localized functional differentiation allows the composite hose to achieve both low permeation and good flexibility simultaneously.
Solution Approach 2:
The invention creates a composite hose structure with alternating thermoplastic and elastomeric layers. The thermoplastic layers (such as PA6, PA66, or PVDF) provide excellent gas barrier properties, while the elastomeric layers (such as EPDM or CR) provide flexibility and mechanical robustness. The direct bonding between layers ensures structural integrity without compromising either property.
3Reliability
If Type E veneer hose design is used, then permeation is reduced, but cost increases and flexibility is limited
Solution Approach 1:
The invention changes the structural parameters of the barrier layers, using thicker continuous thermoplastic layers (0.5-2.0 mm) compared to traditional thin veneer coatings. This parameter change achieves equivalent or superior permeation resistance without requiring complex multi-layer veneer structures, textile reinforcements, or adhesive systems, thereby reducing manufacturing complexity and cost.
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 the lowest refrigerant gas permeation values in the industry, with very low extractible content, improved flexibility, and reduced costs, while maintaining high temperature capability and robustness.
Implementation Method 1
a novel blended elastomer layer that directly bonds to the thermoplastic barrier material without adhesive
Implementation Method 2
exhibits very low permeation ratings for a variety of refrigerant gases including RI 34a and RI 234yf
Data Source
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 an inner elastomeric tube layer capable of direct bonding to plastic without an intervening adhesive. The inner elastomeric layer is prepared from a first elastomeric composition comprising a blend of an ethylene propylene diene terpolymer rubber (EPDM) and a chloroprene rubber (CR), phenylenedimaleimide, and a maleated compound.