Technically Specified or Block Rubber (TSR)

Originally, most of the solid rubber used was in the form of ribbed smoked sheets or RSS rubber. By the early 1970s, however, TSR or rubber was introduced into the market.

TSR which is also known as block rubber is graded according to precise technical parameters such as dirt content, ash content, nitrogen content, volatile matter and properties of the rubber such as its Wallace Plasticity (PO) and its Plasticity Retention Index (PRI).

The TSR grades most widely used by the tyre and rubber industry are the TSR-20 and TSR-10 grades from Indonesia, Thailand and Malaysia which are known as SIR20, STR20 and SMR20 respectively. Block rubber can be produced both from field latex as well as from latex coagulum or what is commonly known as cup- lump. Tree lace and unsmoked sheets can also be used in producing block rubber.

The TSR grades such as grades 10 and 20 are most widely used by the tire industries and made from cup lump also known as field coagulum. These grades include SIR20, STR20, SMR20 which are produced from Indonesia, Thailand and Malaysia respectively. There are other block rubber grades such as SVR3L and SVR CV60 which are made from field latex. These are of more purity thus more expensive and they are mostly used for high-end precision rubber products.

Please see the Table below for a complete list of the all the major TSR grades commonly produced, the raw material from which they are produced and their properties.


Ribbed Smoked Sheet Rubber (RSS)

Ribbed Smoked Sheet Rubber is commonly known as RSS. It is made directly from latex which is treated and then made to coagulate. The coagulated latex sheets are then air dried or smoked in ovens.The smoked sheets are visually graded on the basis of certain parameters and then packed in bales. Please see the table below for specifications of the various RSS grades.

The size and weight of the bales differs according to country. In Thailand the standard packing for RSS is large bales of 111.11 kg per bale and 171 bales or 19 m/tons per 20′ FCL. In Indonesia RSS is packed in bales of 113 kg/bale and 162 bales or 18.306 m/tons per 20’ FCL. In Vietnam the standard packing is in small bales of either 33.33kg or 35kg per bale with 19.2 m/tons or 20.16 m/tons per 20’FCL. In India and Myanmar the standard packing size is bales of 50kg/bales with approximately 19-20 m/tons per 20’FCL.

Thailand still ranks as the largest producer and exporter of sheet rubber followed closely by Vietnam and Indonesia. Though India is a big producer of sheet rubber, all of its production is being primarily consumed by domestic markets.



Concentrated Latex is derived from Field Latex and is processed using centrifuge methods. It contains 60 percent Dry Rubber Content (DRC). There are two main  types of concentrated Latex available in the market and these are the High Ammonia or Standard Ammonia Concentrate (HA Latex) and the Low Ammonia Concentrate (LATZ).

High Ammonia Latex Concentrate (HA Latex) -This is the most common grade of latex used worldwide and after compounding has wide applications in manufacture of dipped products like medical gloves, industrial gloves, rubber thread, balloons, condoms etc. It is also used as an adhesive in many different types of industrial applications such as for carpet backing etc.

Low Ammonia Latex Concentrate (LATZ) – This is centrifuged natural latex concentrate which is preserved with low ammonia with other preservatives. The ammonia content of LATZ is not exceeding 0.29%. LATZ can replace HA Latex in all normal latex applications, with a little adjustment in compounding in certain cases. LATZ is preserved with 0.2% ammonia together with a suitable combination of zinc oxide (ZnO) and tetramethylthiuram disulphide (TMTD) of not more than 0.05% in total, based on latex weight. It is more commonly used whenever lower levels of ammonia content are preferred such as in enclosed spaces.

Concentrated Latex is packed or shipped in three main ways. The first is in steel drums of net weight 205kg/drum. A 20’FCL can carry 80 drums with a net weight of 16.4 m/tons. The second method of packing is in disposable or non-returnable flexi-bags in containers carrying approximately 20m/tons per 20’ container. A third method of transporting latex is through returnable or leased iso-tanks.

Vietnam has become a major producer as well as exporter of centrifuged latex in terms of volume and Vietnam is ranked second in the world after Thailand.


Cup Lump

For the past few years, Namazie international has been active in sourcing for Cup Lump from regions such as West Africa, Philippines and Cambodia. There is a growing demand for Cup Lump especially from countries like Malaysia which has a very big processing capacities but whose domestic production of rubber is insufficient to meet their needs.

We have buying agents in various parts of West Africa who collect the cup lump and ship to various destinations and factories all over the world. The cup lump is either dry before shipment or, if wet, is shipped in plastic bags and containers which are specially lined with plastic sheets to prevent water seepage.