The Science Of Rubber Calendering

Rubber calendering is a mechanical process that utilizes multiple rollers to reduce the thickness of the rubber material. It converts the raw rubber material into a sheet-like formation. With these rollers’ help, you can blend more than two materials.

Rubber Calendering
Rubber Calendering

Step-by-Step Calendering Process for Rubber

The step-by-step process that you need to follow to accomplish the rubber calendering is as follows:

1. Selection of Polymer Granules

The first step in the rubber calendering process is the selection of rubber polymers. There are different material exist to choose from. You can select anyone. An option exists to select more than one polymer material. Please note that the material you select greatly affects the properties you desire in the end product.

2. Preheating

The next step after selecting the appropriate rubber material is preheating. In this stage, the specific polymer is subjected to heat to melt it appropriately. It also refers to controlled heating. The heating does not convert the material to liquid but to semi-liquid. This stage is also optional in some processes because the rollers heat some material during extrusion.

3. Blending

This step is optional. You can follow this step or leave it depending on the end material requirement. The option exists to blend another polymer with the existing one after the preheating stage. This step will increase both materials’ properties and strength, and durability.

4. Feeding & Conveying

When the mixing or bending ends up, there comes feeding and conveying. The semi-liquid material is then put directly into the rollers. These rollers follow clockwise as well as anticlockwise movements. This way, they convey the rubber material to other rollers.

5. Extrusion

When the particular material is conveying, the heated rollers extrude that material to reduce the thickness. They do this by further softening the particular rubber material. The distance between the series of rollers decreases as the material moves on from one roller to another. This further reduces the thickness and results in better extrusion.

6. Cooling

After the end of the extrusion process, there comes the cooling stage. In this process, the heated rubber material gets cooled. The cooling takes place by passing the material through cooled water. This solidifies the particles of rubber.

7. Collection

In the final stage, the finished rubber material wounded over the cylinder for later usage. Or you can collect it from subjecting for a particular application.

Types of Rubber Calendering

Rubber calendering has three main types. These types are:

I-Type

In this type, the rubber calender machine’s rollers follow an arrangement of one over another. This way, they consume up very low floor spacing. Three rollers exist.

I type Calendering
I type Calendering

The upper and lower roller rotates anticlockwise among these rollers, while the middle roller rotates clockwise. In this type, the material first moves through the upper two rollers. Then from the lower two rollers, achieve an optimum thickness reduction. You can get a better level of visibility when using these rollers.

L-Type

As the name reflects in this type, the rollers have an L shape arrangement. There are a total of four rollers present in this formation. Three rollers follow an arrangement, while the fourth roller is perpendicular to the first three rollers.

 L type Calendering
L type Calendering

This type has the formation of inverted L type and non-inverted L type. The non-inverted type you can use for rigid materials calendering, while the inverted type is for flexible materials. The fourth roller, perpendicular to the other three, follows a clockwise rotation. While the remaining three follow a rotation similar to that of I-type.

Z-Type

The name Z-type reflects that this type follows the Z-shape arrangement. In this type, each roller pair is perpendicular to the other pair within the chain. You can face a lower level of heat in this type compared to the other two roller arrangements above.

Z type Calendaring
Z type Calendering

Each roller facing the other roller horizontally follows a different direction of rotation. One rotates clockwise, and the other one rotates anticlockwise. This arrangement of roller leads you to experience a better thickness level.

Material That Is Compatible With Rubber Calendering

There are various materials you can use when it comes to rubber calendering. The main two classes are elastomers and fabric materials. Rubber sheets form due to a combination of both elastomer and fabric materials. At the same time, rubber fabrics contain only fabrics that follow multiple operations of smoothening, glazing, and embossing.

Some of the key materials are:

Sr. No. Elastomers
1 Neoprene Viton
2 Urethane Fluoroelastomer
3 EPDM Natural
4 Nitrile SBR
5 Butyl Hypalon
6 Silicone

 

Sr. No. Fabric Material
1 Rayon Nylon
2 Cotton Polyester
3 Polyester Blends Fiberglass
4 Kevlar Nomex
5 Fiberglass Square Woven Cotton
6 Monofilament Blends

 

Applications of Rubber Calendering

Rubber calendering covers a variety of industries. Some of the key products that you can make using rubber calendering are here for your reference:

Floor Tiles

You can use rubber calendering to manufacture rubber floor tiles. These tiles are widely adapted for playgrounds, gymnasiums, or high-traffic areas. You can cut them to meet custom flooring needs.

Rainwear

The commingled fabric and rubber polymer result in the formation of raincoats or jackets. They completely prevent you from rainwater.

Luminous Ceilings

The term luminous represents illumination. You can use Rubber calendering to form very thin rubber sheeting that you can use in your ceilings. The light filters out through these sheets, producing a calm and relaxing environment.

Wall Coverings

You can use rubber calendering in making wall covers. You can hide moisture or distorted paint on your walls with these sheets. Embossed sheeting gives you a variety of surface textures that make your vicinity pop up.

Pressure Sensitive Tapes

By rubber calendering, you can also form pressure-sensitive tapes. As the name reflects, you can stick them to any surface you want with just a slight pressure. These tapes are popular in a variety of industries.

Furniture Upholstery

Rubber webbing replaces jute webbing because of unmatchable strength, flexibility, and durability. You can use it on various furniture accessories to make them aesthetically pleasing.

Benefits of Rubber Calendering Process

Wondering what adds up to the worth of rubber calendering investment. These are the benefits similar to these in the true sense.

Complete Thickness Control

You can control the end thickness of the sheet or material used for rubber calendering. An option exists to adjust the distance between the rollers for the optimum level of thickness. Considering this, you can cope with the various products’ production needs.

Seamless Finish

As in rubber calendering, the material passes through multiple rollers. This results in a seamless and smoother end finish. The level of finish is such that you don’t need to further subject it to finishing processes.

Higher Strength

By receiving constant compression from a series of rollers. The number of molecules within the structure drives closer so that no spacing remains behind. This improves overall strength and durability.

Things That Need Your Attention During Rubber Calendering

Suppose you don’t pay attention to the following things. Then you can experience a waste of time, cost, and material.

Melting Temperature

Before extrusion, adjust the temperature of the heating element within the roller. While doing so, consider the melting point of the specific material if you fail to do or set it at a lower or higher number. Then the results are devastating. Either you will face a complete melting or no optimum melting. The optimum temperature allows your rubber material to adopt effective shaping and thinning.

Roller Speed

The higher roller speed indeed increases the overall production. But the plasticity of the rubber compound matters while tweaking the overall roller speed. Set the speed of the roller to an optimum level. Not too high or not too low.

Rubber Plasticity

The higher level of plasticity can lead you to good fluidity, which effectively obtains a smooth film. If plasticity increases beyond an optimum level, it can lead to sticking. This, in turn, affects the surface finish because of the enhancement in shrinkage rate.

Conclusion

Now you have complete information about calendering rubber. You can either set up your plant or improve your calendering process accordingly. Feel free to share this masterpiece with your friends or colleagues.

If anything confuses you or you need assistance in this regard. Feel free to reach out for quality assistance services. We would love to help you out!

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