Natural Rubber
Natural rubber, in its milky sap, is tapped from the Hevea Brasiliensis tree. Most of the latex is either processed into sheets or solid crumb rubber. It can also be kept in its liquid form through use of chemicals to prevent the latex from coagulation. In the solid form, the rubber sheets or crumbs are used in the manufacture of solid rubber based products, e.g. tyres etc, while the liquid form is used for dipping products such as gloves, balloons and condoms.
Technically Specified Rubber (TSR)
Rubber grading under TSR was established in the early 1970s. The rubber is graded by its dirt, ash, nitrogen content, volatile matter content and plasticity retention index.
They have good processing characteristics and physical properties. Usually, such grades of rubber are high in green strength, tack, easy to mix and has low viscosity.
Common sources of TSR include Malaysia, Indonesia, Thailand, India, Vietnam etc. Depending on the countries the rubber is from, the rubber labeled accordingly. SMR, Standard Malaysia Rubber, is from Malaysia. SIR, Standard Indonesia Rubber, is from Indonesia.
These are used in high performance passenger tyres, motorcycle and bicycle tyres, heavy load truck tyres, conveyor belt, inner tubes and hose.
There are other grades of rubber which are not listed here. R1 trades all these other grades of rubber too.
A Typical Technical Specification of Standard Malaysian Rubber (SMR):
| SMR10 | SMR20 | |
|---|---|---|
| Dirt % wt max | 0.08 | 0.16 |
| Ash % wt max | 0.75 | 1.00 |
| Nitrogen % wt max | 0.60 | 0.60 |
| Volatile matter % wt. max | 0.80 | 0.80 |
| Acetone extract % wt max | 5.00 | 5.00 |
| Copper content max | 8 PPM | 8 PPM |
| Manganese content max | 10 PPM | 10 PPM |
| Po Min (Plasticity) | 30.00 | 30.00 |
| PRI % min | 50.00 | 40.00 |
| Mooney Viscosity | 70.00 - 90.00 | 70.00 - 90.00 |
