A Complete Guide About Calendering Rubber

How the calendar can improve the properties of rubber? No, we are not talking about the 12-month calendar on the wall. Calendering is actually a finishing process that improves the rubber and makes it high-performing. These rubbers are predominantly used in making products like gaskets, o-rings, seals etc. Most of the manufacturing companies prefer calendered rubber than the standard rubbers.

The high-tech rubber calendering services use different kinds of machines to carry out the ironing process that smoothens the rubber by placing it between the rollers and maintaining pressure. Over 500 pounds per square inch (psi) pressure is exerted on the rubber. Apart from pressure, even heat is used in making the calendered rubber. 

Though the basic materials present in the standard rubber and calendered rubber is the same, however, this processed form of rubber certainly possesses many advantages as compared to the counterpart.

Here are the basic advantages of calendered rubber:

Much stronger:

The calendering process increases the strength of the rubber. As mentioned before, the rubber is processed by exerting extreme pressure (almost up to 500 psi), hence the rubber is compressed and which eventually makes the calendered rubber much robust and extremely durable.

Rubber with smooth finishing:

Yes, calendering improves the properties of the rubber by making it smooth. The smooth finishing is obtained by the heat and pressure used while calendering the rubber. The cutting edge machines used for calendering remove the lumps and eliminate the imperfections thus giving a smooth finishing to the calendered rubber.

After the process in the calendering machine is completed and the rubber is cooled off, it automatically develops a smooth texture which probably is not attainable with any other finishing processing techniques.

Manage rubber thickness as per need:

One of the biggest advantages of calendered rubber is that you can manage the thickness of the rubber as per the specific need of a product. It is very critical to have a proper rubber for products like seal or gasket as there are chances of leakage.

With the calendering process, the rubber can be made of a specific thickness that is required by manufacturing companies to create gaskets or seals. The thickness of the rubber is managed by managing the distance between rotating rollers. When the rotating rollers are brought close together then it leads to a thin type of calendered rubber while the rotating rollers are moved apart from each other, then thicker calendered rubber is created.  

In rubber industries, calendering is also used for purposes like:

1. Manufacturing rubber sheets with one side patterns
2. Creating double-coated rubber surfaces
3. For textile coating with rubber

Different types of rubber calenders

The types of rubber calenders depend upon the number of rolls and the position of rolls.

Their varied types include 2, 3 and 4-Horizontal Type Calender, 2, 3 and 4-Vertical Type Calendar, 2-Roll Inclined Type Calender, 3-Roll Offset Stack Calender, 4-Roll Offset Stack Calender (Inverted ‘L’ Type), 4-Roll Offset Stack Calender (‘S’ Type) and 4-Roll Offset Stack Calender (‘Z’ Type).

Initially, the calendering process was only limited to rubber but now the process is commonly used in manufacturing thermoplastic sheets, films and coatings.