Natural Rubber Basics | Technically Specified Rubber

Raw Natural Rubber can be more or less broadly divided into the following 4 categories: Visually Graded Rubber, Technically Specified Rubber, Natural Rubber Latex, and other forms of natural rubber. In this post, let us shine a spotlight on Technically Specified Rubber (TSR).

What is Technically Specified Rubber?

Technically Specified Rubber (TSR) is a relatively new type of natural rubber. The world only produced what is now called Visually Graded Rubber, up until 1960s when rubber in the form of crumbs pressed into bale form were developed. This new form of rubber could not be graded visually, so a scientific method of analysis was first developed, in Malaysia, in order to grade each rubber type and thus TSR was born. Out of the 4 main categories of Natural rubber, this type is now the most produced, and is used for a wide range of products from tires and anti-vibration rubber to raw material for tape adhesives.

The main characteristic of TSR is that its specification is determined by a scientific method of analysis

For example, the Vietnamese TSR SVR-3L is specified under the following specifications:

Because the TSR has it specifications defined technically, we can hope that it will make it easier for potential users to choose between the different grades, and also that the quality and physical properties will be more stable. Also all TSRs are below 35kg per bale and palletized… so the handling is much easier compared to big bales of some Visually Graded Rubbers (over 100kg per bale!).

Naming of Technically Specified Rubber

There is an international rule to the way each TSR grade is named. By remembering this simple rule, one can determine the country of origin and the specs just from the name of the grade.

Lets take the SVR-3L again as an example:

SVR ⇒ Standard Vietnamese Rubber

The middle letter can tell us the country of origin.

SIR = Indonesia

STR = Thailand

SMR = Malaysia

3L

The letters/numbers following the SVR part is the grade of the rubber. Each grade is made from differing materials, processes and uses, and is sorted by different HS codes (See below for reference).

Production Method: Latex Grade

This grade is relatively of higher quality. When harvesting the rubber tree sap, the trunk of the tree is cut and the sap that drips down (field latex) is collected in a small cup. After a couple of hours, the cup is filled and all the field latex is taken to the factory, where it is processed in to various different latex grades.

Production Method: Cuplump Grade

The quality of this grade is relatively lower. After the latex collection process as written above, there is a small amount of field latex left inside the cup after collection. After a while this residue dries and hardens. This is what is called a cuplump and the various solid rubber grades that are made from this are called Cumlump grades. Compared to the latex grade rubbers, cuplump grades are relatively darker, smell stronger, and the quality tends to be unstable.

Our Products

We mainly handle TSR from Vietnam. If you are interested, please look through Main Products page, and casually send us any inquiries from our contact form at the bottom of our website.