PVC Gasket Extrusion Line
Product Overview
The PVC Gasket Extrusion Line produces precision gasket profiles for refrigerator doors, oven doors, windows, and industrial equipment. These gaskets provide airtight, watertight, and thermal seals critical for energy efficiency in appliances and building products.
The line features a single-screw extruder with precision die, optional steel strip co-extrusion unit for magnetic gaskets, hot air vulcanization tunnel, and cutting/winding system. It handles both standard PVC gaskets and magnetic gaskets with embedded flexible magnetic strips used in refrigerator door seals.
Refrigerator gaskets represent the largest application segment. These gaskets typically feature a magnetic strip embedded in a PVC bulb that magnetically adheres to the refrigerator steel door frame, creating an airtight seal that prevents cold air loss. The steel strip co-extrusion unit enables this integrated production.
PVC gaskets require excellent compression set resistance — the ability to return to original shape after prolonged compression. Our formulation guidance includes specific compound recipes optimized for low compression set, ensuring gaskets maintain their sealing performance over years of door opening and closing cycles.
Key Features
Single-screw extruder with precision die
Steel strip co-extrusion unit
Magnetic gasket forming station
Hot air vulcanization tunnel
Cutting and winding system
Production Process
From raw material to finished product — each step is engineered for quality and efficiency.
Compound Preparation
Flexible PVC compound with low compression set formulation, food-grade stabilizers for refrigerator applications, and appropriate plasticizer for target Shore A hardness.
Extrusion & Die Forming
The extruder produces the gasket profile through a precision die. For magnetic gaskets, a magnetic strip is fed into the die and co-extruded within the PVC bulb.
Steel Strip Co-Extrusion
For magnetic gaskets, a flexible steel strip is simultaneously co-extruded into the gasket base, creating the magnetic attraction surface for refrigerator door adhesion.
Vulcanization Tunnel
The gasket passes through a hot air vulcanization tunnel (180-220°C) that completes the cross-linking process, improving elasticity and compression set resistance.
Cooling & Haul-off
Controlled cooling finalizes the gasket properties. A caterpillar haul-off maintains consistent speed for dimensional accuracy.
Cutting & Winding
The gasket is cut to specified lengths or wound onto spools for subsequent corner-welding into finished gasket frames.
Technical Specifications
| Extruder Model | SJ-45/25 or SJ-65/25 |
|---|---|
| Gasket Type | Magnetic / Standard |
| Co-extrusion | Steel strip integration |
| Production Speed | 8-20 m/min |
| Total Power | ~20-40 kW |
| Line Length | ~15m |
Why Choose Wings Plastic
Magnetic Gasket Capability
Integrated steel strip and magnetic strip co-extrusion system enables production of refrigerator magnetic door gaskets — a high-value, high-volume product category.
Low Compression Set
Formulation guidance includes recipes optimized for compression set below 25% (70°C, 22h), ensuring gaskets maintain sealing force over years of service.
Food-Grade Compliance
Line and formulation support food-grade PVC compounds (FDA 21 CFR 178.3740) for refrigerator and food processing equipment gaskets.
Precision Die Design
Custom dies produce exact gasket cross-sections including bulb profiles, mounting grooves, and magnetic strip channels — all with ±0.1mm dimensional tolerance.
Vulcanization Tunnel
Hot air vulcanization improves cross-link density, elasticity, and heat resistance — critical for oven gaskets and high-temperature applications.
Quality Assurance
Every production line undergoes rigorous quality verification before delivery:
- Magnetic strip pull-out force tested to verify embedment security
- Compression set tested per ASTM D395 Method B at 70°C for 22 hours
- Gasket cross-section dimensions verified under optical comparator
- Food-grade certification testing for refrigerator gasket compounds
Typical Applications
Frequently Asked Questions
A magnetic gasket has a flexible magnetic strip embedded in the PVC bulb. When installed on a refrigerator door, the magnet adheres to the steel door frame, creating an airtight seal without mechanical latches. This is the standard sealing method for modern refrigerators.
Properly formulated PVC gaskets last 8-15 years in normal use. The main failure mode is plasticizer migration causing hardening. Low-migration plasticizers (DOTP, TOTM) extend lifespan significantly.
Yes, with heat-resistant formulations (using TOTM or polymeric plasticizers) and the vulcanization tunnel, the line can produce gaskets rated for continuous use up to 150°C — suitable for oven and industrial equipment applications.
Yes, we provide food-grade formulations compliant with FDA 21 CFR 178.3740 and EU 10/2011 for refrigerator and food processing equipment gaskets. Migration testing is supported.
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