Co-Extruded Rubber Seals Factory | OEM Supplier

If you are sourcing co-extruded rubber seals for a project that demands a rigid mounting base bonded to a soft sealing lip—such as automotive door seals, window glazing gaskets, or appliance cabinet gaskets—you need a factory that controls both the polymer matrix blend and the die flow balance during co-extrusion. At Hunan Zhouxin Sealing Technology Co., Ltd., we have run over 500 overseas co-extrusion projects across EPDM, silicone, and TPV materials. This guide walks you through the procurement process step by step.

Factory Capability Comparison for Co-Extruded Rubber Seals

Not every extrusion line can handle co-extrusion. A true co-extruded rubber seals factory must have dual-extruder heads, a shared vulcanization tunnel, and precise temperature control at the bonding interface. Below is a capability matrix we use internally when qualifying new tooling for overseas buyers.

Capability	Standard Extrusion	Co-Extrusion (Our Factory)
Number of durometer zones	1	2-3 (e.g., 70 Shore A rigid base + 40 Shore A soft lip)
Material combinations	Single elastomer	EPDM/EPDM, EPDM/silicone, TPV/EPDM, silicone/silicone
Bond strength (peel test)	N/A	> 4 N/mm (ASTM D903)
Max cross-section width	120 mm	80 mm (due to dual-flow balance)
Tolerances (critical dimensions)	±0.30 mm	±0.20 mm
Color options	Black only	Black base + colored lip (any RAL)

In our Hunan factory experience, the most common overseas rejection we see is delamination between the hard and soft layers—usually caused by an insufficient bonding window during vulcanization. We solved this by adding a third temperature zone in the curing oven, which increased our bond consistency from 87% to 99.2% in 2022.

MOQ, Tooling Cost, and Sample Lead Time

Minimum Order Quantity (MOQ)

For standard co-extruded profiles (cross-section < 40 mm), our MOQ is 500 meters per durometer zone. For complex profiles with metal inserts or flocking, MOQ rises to 1,000 meters. We can negotiate lower MOQs for first-time buyers if you cover tooling cost.

Tooling Cost

A co-extrusion die costs $800–$2,500 depending on cross-section complexity and number of flow channels. This includes one round of sampling at no extra charge. Tooling is amortized over the first three production orders.

Sample Lead Time

After CAD approval, sample production takes 7–12 working days. Air freight (DHL/FedEx) takes 3–5 days to most global destinations. We provide dimensional inspection reports (ISO 3601) with every sample.

How to Send Proper CAD Drawings to Reduce Back-and-Forth

A poor drawing adds 3–5 email loops before tooling starts. Follow this checklist:

1. Export as .STEP or .IGES – These preserve 3D geometry without proprietary layers. Avoid .PDF for critical dimensions.
2. Call out tolerances per ISO 3302-1 – For co-extruded seals, specify Class E1 (±0.30 mm) for mounting grooves and Class E2 (±0.60 mm) for sealing lips.
3. Indicate durometer zones – Use cross-hatching or color layers to show where hard (70–80 Shore A) and soft (40–50 Shore A) material should be.
4. Mark the bonding interface – A simple dashed line where the two flows meet ensures we align the die correctly.
5. Include a material specification sheet – Reference ASTM D2000 line callouts (e.g., 2AA-715 for EPDM) or your own performance targets.

We provide a free drawing checklist PDF upon request. If you send a .STEP file, we return a tooling design review within 48 hours.

Material Selection for Co-Extruded Profiles

Co-extrusion allows you to combine properties that a single durometer cannot achieve. Common pairings:

Base (Rigid)	Lip (Soft)	Typical Application	Temperature Range
EPDM 80 Shore A	EPDM 45 Shore A	Door sealing strips for vehicles	-40°C to 150°C
Silicone 70 Shore A	Silicone 30 Shore A	Cabinet seals for ovens	-60°C to 230°C
TPV 75 Shore A	TPV 50 Shore A	Window glazing (PVC-free)	-40°C to 125°C
EPDM 85 Shore A	Silicone 40 Shore A	Appliance gaskets (flame retardant)	-40°C to 200°C

Key Performance Metrics

• Tensile strength: > 7 MPa for EPDM base, > 5 MPa for silicone lip (ASTM D412)
• Compression set: < 25% for EPDM (22 h @ 70°C, ASTM D395 Method B)
• Ozone resistance: No cracks after 72 h @ 50 pphm, 40°C (ASTM D1149)
• Flame retardancy: UL 94 V-0 for silicone compounds
• Thermal aging: < 15% change in tensile after 168 h @ 100°C (ASTM D573)

Packing and Export Logistics

Co-extruded seals are packed on wooden spools or in cardboard coils, depending on profile stiffness. Standard packing:

• Spools: 100–300 meters per spool, wrapped in stretch film, with edge protectors
• Coils: 50–100 meters per coil, polybagged, then in corrugated cartons
• Export pallets: 1.2 m x 1.0 m, fumigated (ISPM 15), shrink-wrapped with corner guards

We ship FOB Shanghai or Shenzhen. For air freight, profiles are cut to 2-meter straight lengths and packed in plywood cases. All shipments include a packing list, commercial invoice, and material test certificate.

Frequently Asked Questions

What is your MOQ for co-extruded rubber seals?

Our standard MOQ is 500 meters per durometer zone. For profiles under 20 mm cross-section, we can reduce to 300 meters on the first order. Contact us with your profile cross-section and annual volume for a custom MOQ.

What is the typical lead time for tooling and samples?

Tooling fabrication takes 7–12 working days after CAD approval. Samples ship within 3–5 days via air freight. Production lead time for first order is 15–20 working days after sample approval.

What extrusion tolerances can you hold?

We hold ±0.20 mm on critical mounting dimensions and ±0.40 mm on non-critical sealing lips, per ISO 3302-1 Class E1/E2. For profiles with metal reinforcement, tolerances widen to ±0.50 mm.

How do you pack co-extruded seals for export?

Profiles are wound on spools (100–300 m) or coiled (50–100 m), then packed on fumigated pallets. Each pallet is stretch-wrapped and labeled with part number, quantity, and heat number. We also offer cut-to-length options for air freight.

Can I get free samples before placing a production order?

We provide one free sample set (3 meters) after tooling approval. Shipping is at your cost. For standard profiles from existing dies, we send free samples within 48 hours—you pay only shipping.

Send Your CAD Drawing for a 24-Hour Quote

Parameter	Our Capability
Max cross-section	80 mm
Min wall thickness	0.8 mm
Durometer range	30–90 Shore A
Material options	EPDM, silicone, TPV, NR, CR
Certifications	ISO 9001:2015, IATF 16949 (pending)
Export markets	North America, Europe, Middle East, Southeast Asia

Email your .STEP drawing with material and durometer requirements to our engineering team. We will respond with a full quotation—including tooling cost, MOQ, and lead time—within 24 business hours.