RUBBER

Rubber products are connected to almost every part of modern day life; from tyres and automotive components to industrial hoses, flooring, food and medical applications and adhesives rubber products can be found virtually everywhere.

Globally twenty five million tonnes (25,000,000 t) of natural and synthetic rubber are produced, traded and consumed every year. As the world economy grows with increasing industrialisation of emerging economies demand for rubber products and rubber continues to increase.

Natural rubber is the oldest type of rubber but still accounts for more than 40% of the total volume, currently a little more than ten million tonnes per year and its usage continues to grow. Natural rubber is produced from the cultivation of the Hevea Brasiliensis tree, which as the name suggests originated in South America.

Natural rubber is a naturally occurring high-cis poly-isoprene. In a sample of natural rubber approximately 94% will be poly-isoprene with the balance made up of some naturally occurring resins and proteins, together with small amounts of ash, dirt and water. It is the resins and proteins together with the high-cis poly-isoprene which give natural rubber its unique properties.

The main natural rubber producing countries are nowadays Thailand, Indonesia, Malaysia, India, Vietnam and China. Also West Africa is becoming a more significant Natural Rubber producing region. Natural rubber was originally processed into visually graded types, such as Ribbed Smoked Sheets (RSS), numbered 1 – 5, and Brown and Pale Crepes. The Technically Specified Rubber (TSR) scheme was introduced in Malaysia about 50 years ago in order to provide consumers with measurable data of rubber properties. Now TSR grades such as SMR-10, SIR-20 and SVR-CV60 account for roughly 80% of global production and consumption.

Synthetic rubber was first produced in Germany in the middle of the 20th Century and now synthetic rubber grades and types account for the majority of rubber demand. Synthetic Rubber is produced by the polymerisation of monomers typically Styrene and Butadiene which are polymerised to produce Styrene Butadiene Rubber, SBR and also Poly-Butadiene Rubber, BR. Subsequent developments have seen the introduction of other monomers such as ethylene and propylene which are used in the production of EPDM. Other types of synthetic rubber include: Butyl, more correctly know as Isobutylene Isoprene Rubber, and this can be modified with halogen atoms such as Chlorine or Bromine to produce Chlorobutyl and Bromobutyl, together known as Halo-Butyls and Nitrile (acrylonitrile butadiene). There is even a synthetic version of natural rubber called Polyisoprene.

Synthetic rubber is now produced all over the world, with the major producing countries being China, the United States of America, Japan, Republic of Korea and Germany.

Applications for both natural and synthetic rubber include a wide and diverse product range including tyres, tyre re-treading, adhesive and adhesive tapes and labels, rubber flooring, industrial hoses, gaskets, rubber to metal bonded parts and anti-vibration system components, pharmaceutical products, dipped goods such as latex gloves, condoms and catheters and many others.

 

 

Rubber type

Benefits

Limitations

Typical applications

Natural Rubber

Widest range of hardness
Very strong &
naturally self reinforcing
Good compression set
Good resistance to inorganic chemical

Lack of oil and organic fluids resistance
Max temperature 75 - 100°C
Poor ozone resistance

Sealing and shock absorption
Conveyor belting
Truck tyres

EPDM

Rubber with greatest water resistance
Very inert structure
Stable over long periods of time
Very good weather resistance
Easy to compound and process

Not resistant to oil and oil products
Relatively poor compression set

Automotive weather strips
Windows and doors sealing
Automotive hoses (not fuel)

SBR

Good physical strength
Good tear and abrasion resistance

Poor oil and fuel resistance
Poor weather resistance

Non-mechanical high volume products
Shoe soles and car tyres

Polybutadiene

Good abrasion resistance
Low glass transition temperature
High resilience

Very poor ozone resistance

Tyres
Conveyor belts
Polystyrene and ABS modification

Butyl Rubber
Isobutylene Isoprene

The highest performing rubber for impermeability
Good flexural properties
Good ozone resistance

Poor abrasion resistance

Tyre linings and inner tubes
Roofing products
Fuel and lubricant additive