Adhesive-Free Rubber-Polyamide Hose for Low Permeation
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Solution Overview
Problem
Existing automotive refrigerant hoses face issues with temperature stability, permeation, and adhesion, particularly due to the use of adhesives in bonding rubber and plastic layers, which can lead to spotty adhesion and increased permeability to refrigerants.
Innovation Solution
A hose design featuring a direct bonding of an EPDM rubber backing layer to a polyamide layer without an intervening adhesive, utilizing a rubber backing composition comprising ethylene propylene diene monomer (EPDM), phenylenedimaleimide, and a maleated compound, which enhances adhesion, temperature stability, and reduces permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to bond rubber layer to plastic layer, then bonding between layers is achieved, but adhesion becomes spotty and permeability increases
Solution Approach 1:
The patent removes the adhesive layer entirely from the hose structure, eliminating the source of spotty adhesion and permeation problems. The rubber and plastic layers are bonded directly through molecular entanglement and chemical bonding mechanisms inherent in the material interface, without any intervening adhesive substance.
Solution Approach 2:
The patent employs a composite material structure where the rubber backing layer and plastic veneer layer are directly interfaced. The composite nature of the materials themselves provides the bonding mechanism through compatible surface chemistry and molecular interdiffusion at the interface, replacing the need for separate adhesive materials.
2Ease of manufacture
If standard rubber composition is used, then manufacturing is simplified, but temperature capability is limited
Solution Approach 1:
The patent modifies the chemical composition parameters of the rubber backing layer by incorporating specific compounds (polyamide, polyester, or acrylic) that alter the material's thermal properties. These compositional changes enable the rubber to maintain flexibility at low temperatures and resistance at high temperatures while remaining compatible with standard manufacturing processes.
Solution Approach 2:
The patent creates a composite rubber formulation by combining base rubber materials with functional polymers (polyamide, polyester, or acrylic). This composite approach enhances the temperature capabilities of the rubber without fundamentally changing the manufacturing process, as the composite materials can be processed using conventional extrusion and vulcanization methods.
3Strength
If adhesive layer is inserted between rubber and plastic layers, then bonding is achieved, but hose complexity increases
Solution Approach 1:
The patent eliminates the adhesive layer from the hose structure, reducing the number of components and simplifying the overall construction. The direct interface between rubber and plastic layers reduces structural complexity while maintaining bonding integrity through material-compatible interfaces.
Solution Approach 2:
The patent merges the bonding function directly into the material interface between rubber and plastic layers, eliminating the need for a separate adhesive component. The bonding mechanism is inherent in the material pairing rather than being provided by an additional layer, thereby simplifying the hose structure.
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 solution provides improved adhesion, increased high and low temperature capabilities, and decreased permeation, with the hose exhibiting superior performance compared to standard automotive refrigerant hoses, as demonstrated by reduced permeation values for refrigerants R-134a and R-1234-yf.
Implementation Method 1
the rubber backing layer is directly covalently bonded directly to the polyamide layer without adhesive
Implementation Method 2
utilizing a rubber backing composition comprising ethylene propylene diene monomer (EPDM), phenylenedimaleimide, and a maleated compound
Data Source
AI summary
A hose is provided comprising a rubber backing layer directly bonded to a continuous polyamide layer without an intervening adhesive layer, wherein the hose exhibits increased low and high temperature capability and decreased permeation compared to standard automotive refrigerant hoses.