Rubber Extrusion Manufacturers in China – Leading Supplier of EPDM Rubber Extrusions with IATF 16949 Certificate
Get to know rubber extrusion process
Rubber extrusion products have a constant cross-section along the entire length of the product. Typical extruded rubber products include tubing, seals and gasket profiles and weather stripping.
In the extrusion process, the rubber compound sheet is fed into an extruder. The extruder consists of a rotating screw inside a close-fitting heated barrel. The purpose of the extruder is to soften, mix and pressurize the rubber as it is continuously conveyed to a shaping die at the extruder exit.The die is a metal disk with a machined opening in the desired shape of the extruded part. The pressure built up by the rotating screw forces the rubber, which has been softened by the heating, through the die opening—shaping it into the profile cut in the die.
When the rubber shape (extrudate) exits from the die, the material swells so that the part cross-section is larger than the die cross-section. This phenomenon is called “die swell”; depending on the rubber formulation and the extrusion conditions, the dimensions of the extrudate may be increased by several percent to several hundred percent beyond those of the die. Furthermore, except for circular cross-sections (i.e., circular cords), the rubber does not swell uniformly in all directions. For example, in order to extrude a square cross-section, the die must be cut so that the sides of the square are curved inward. After leaving the die, the rubber extrudate must be cured or “vulcanized” to maintain its shape and acquire the physical properties necessary for the application.
After leaving the die, the rubber extrudate must be cured or “vulcanized” to maintain its shape and acquire the physical properties necessary for the application. This is accomplished by a chemical reaction (the cross-linking of molecules) from peroxides or sulphur curing agents. Vulcanization is initiated when the extrudate temperature is raised by passing it through a curing media, such as a microwave and/or a hot air process.
Curing is the final step in the rubber extrusion process, although the extrudate frequently undergoes secondary processing such as slitting, splicing, cutting to specified lengths etc.
What are the advantages of Rubber Extrusion and Rubber Extruded Products?
- A continuous extrusion process can produce finished products in different lengths
- Raw materials can be formed into unique profiles with a variety of lengths and shapes
- Extruded rubber products or “extrudates” have flexible characteristics and are highly resistant to chemicals and heat
What are the Common Profiles of Rubber Extruded Products?
Rubber extruded profiles may vary depending on the application. They are commonly applied to industrial applications that require sealing.
Although many other profiles can be made, there are also profiles that are readily available on the market.
- Door Seal Profiles. Also known as extruded top and side seals, these profiles are designed to fill the gaps between doors and door frames to prevent wind and water from entering a vehicle or building. Door seals are typically rectangular. They are used in cars and trucks, as well as in many commercial and industrial facilities. Door seals such as hatch seals can also be found in fuel tanks, rooftop HVAC systems and in electronic enclosures.
- PVC Edge Trim Profiles. PVC edge trim profiles are used to cover rough edges made from plastics and steels. These types of rubber extruded profiles are made from flexible PVC and have gripping tongues that allow them to provide a much stronger hold. PVC edge trim profiles are usually found in automotive and marine industries and are used for applications such as decorative trims for boats, cars and buildings.
- Boot Seal Profiles. Boot seals are used as a coating for the sharp metal edges of the boot of a car/vehicle. Preventing dust and water from entering the vehicle, they also prevent noise and vibration when travelling.
Whether by extrusion or any other rubber processing methods, there is no denying that rubber is an excellent material for many everyday applications.
Rubber Extrusion Manufacturers in China – EPDM Rubber Extrusion Suppliers
Hebei Shida Seal Group is a well-recognized manufacturer of rubber extrusions and extruded rubber products produced in China in our facility in Qinghe, Hebei. We produce custom rubber profiles in all standard and custom engineered configurations from all basic elastomers, including dense and sponge materials. We use the finest rubber polymers that offer top of the line products, excelling in rubber extrusion, splicing, die tooling and product development. Our custom rubber extrusion profiles are manufactured to exact specifications from your print or sample and can be produced with no Minimum Order Quantity.