RIOMIRUBBER KNOWLEDGE BASE
Home / Industrial Applications

Which Layer in a Hose Uses Natural Rubber?

Updated: 2026-10-08 · RIOMI Editorial · Industrial Applications
Quick AnswerHoses must be assessed layer by layer—inner tube, inter-ply compound, and outer cover: oil-resistant inner tubes typically use NBR/HNBR, cooling water hoses use EPDM, while NR more commonly appears in general-purpose hoses or inter-ply compounds; the key issue is not "whether you produce hoses," but "in which specific layer is natural rubber applied."

Three-Layer Construction

The inner tube is in direct contact with the conveyed medium and is selected based on media compatibility: NBR and HNBR are standard for oil-resistant service, EPDM is common for cooling water and steam applications, while natural rubber is limited to certain general-purpose media.

Inter-ply rubber must adhere to fiber or steel wire reinforcement and withstand flexural fatigue; natural rubber provides superior adhesion and fatigue resistance in this layer.

The outer cover protects the hose body and faces more stringent requirements for weathering, abrasion, and ozone resistance; it is often blended with or replaced by CR, EPDM, and similar polymers.

Verification Points

Critical hose performance criteria include burst pressure, impulse life, inter-ply adhesion, and media resistance; ISO 8033 defines test methods for adhesion between component layers. When switching to a new raw rubber source, inter-ply adhesion and impulse testing reflect real-world risks more accurately than individual raw rubber properties.

hoseinner tubereinforcement layerouter coverNBREPDM

Sources & Further Reading

Related Topics