A – History: Natural and synthetic rubber
The indigenous people of the Americas were using rubber long before the European arrival of Padre D’anghiera in 1525. In 1735, Charles De la condamine did the first scientific study of rubber. He decided that it was really just resinous oil. We believe that magelian, a relative of the famous explorer first used rubber as an eraser. Borrachia is a Portuguese word that means rubber and it was first used by the Portuguese to make jars to pack their wine in for export. It was Macquer that thought that rubber could be made into tubes. In 1820, an industrialist from England named Nadier made rubber threads and tried to incorporate them into clothing. Soon, England produced world exports of waterproof fabrics such as snow boots and jackets.
In 1825, Hancock, a leading manufacturer of rubber in England invented a rubber mattress. His friend, McIntosh produced the famous McIntosh rain jacket. He also developed a process to cut, roll, and heat and press rubber with a machine in order to mass-produce it. From these developments, Hancock acquired vulcanized rubber from Goodyear and discovered its secret which made him rich.
In 1845, R.W. Thomson invented the innertube, pneumatic tires and textured treads. By 1950, toys made of rubber being processed along with tennis and golf balls. Chemists soon tried to learn more about the various properties of rubber in order to exploit this raw material. The Russians and the Germans tried to synthesize the rubber, but with little success. Not until the First World War, did Germany by necessity develop synthetic rubber to compete with natural rubber in order to contribute from the war effort.
History: Natural Rubber
Latex is a product that is mainly collected from the Brazilian rubber tree (Helea Brasiliiensis) which is native to Amazonia. Brazil’s history of rubber is similar to the Gold Rush stories of North America. In the second half of the 19th century to the second decade of the 20th century was the most important boom in Brazil. It was incorporated into the industrial revolution.
Due to the many applications of rubber used worldwide, the latex from the rubber trees was in high demand. This led to one of the poorest parts of Brazil and the least inhabited to explode. With thousands of immigrants, foreign banks and many other companies that followed money. To become a flourishing community. The northern towns of Belem and Naus were booming.
Brazil hit an output of 42,000 tons of rubber produced per year and controlled the world’s market until about 1910. Their downfall was due mainly to the British smuggling of rubber trees out of Brazil in 1876 to London. In London, they were grafted (cloned) and were developed into a more resilient tree. From that point on, they were sent to the colonies of Malaysia, Ceylon, and Singapore where large plantations were created.
Brazil and the colonies differ in production mainly by the location of the rubber trees. In Brazil, the trees were far apart and took much longer to mature, therefore making them more expensive to collect than in the colonies. Because, the rubber trees in the colonies were planted about four meters apart, they were cheaper and more easily productive. Brazil’s government would not conform with the new harvesting methods and of course this led to their economic downfall.
When Henry Ford was producing 50% of the world’s automobiles, he needed a cheap source of rubber. He partnered with the Brazilian government, with Ford agreeing to plant 17 million rubber tree seedlings in Para state. The project was called Fortlandia by the locals. They were to produce 300,000 tons of rubber a year, or, about half of the world’s consumption, but the project failed mainly due to the hostile environment of the Amazon Jungle. Ford lost a huge amount of his investment.
Asia controlled 90% of the world’s natural rubber production. China and India were trying to evolve in an attempt to lead world production mainly because of their large cheap labour force and they also consumed 40% of the world’s demand of rubber.
B – Latex Facts
Natural latex rubber was made possible by the invention of vulcanization. Vulcanization was first patented in 1843, by a gentleman named Thomas Hancock. Vulcanization is a process by which sulphur is added as part of the chemical process of converting natural rubber into a more durable product.
Over the years there have been different processes developed to enhance the make-up of rubber, and this led to the Talalay and Dunlop processes.
In the Talalay process, the latex is aerated in order to give it a malleable feel. Right after this process, it is frozen to minus 20 degrees Fahrenheit. This makes the latex consistency even. After the freezing, high heat is introduced for about 60 minutes, the latex is cleaned and dried to remove residual moisture.
In the Dunlop process, it does not use the freezing or aerating process, therefore the latex is not as consistent as in the Talalay process.
Latex is a natural material that is harvested from a renewable resource from the rubber tree (Havea Brasilensis). This harvesting is done in a very similar way as to maple syrup where some bark is removed and a spigot is placed into the tree. The rubber then is dripped into a collection tub and then shipped off for processing. The spigot is removed periodically and the tree will replace the bark and continue to thrive and produce rubber.
The major producer of rubber up until 1910 was Brazil. It dominated the global market. Then Britain exported some seeds that were germinated in London. From there, the seedlings were exported to Ceylon (now Sri Lanka). The seedlings were then sent off to Malaysia, Singapore, Thailand, and Indonesia. These countries produce the vast majority of rubber today.
Commercial natural rubber latex exports originate in:
- Thailand (168,000)
- Indonesia (26,000)
- Malaysia (109,000)
- Sri Lanka (3,000)
These countries are all located in South-east Asia.
Brazil provided the world with the rubber tree, Hevea Brasiliensis, but that country no longer plays any significant part in the world NR (natural rubber) trade.
The seeds were germinated at the Tropical Herbarium in Kew Gardens, London later that year. From there seedlings were exported to Ceylon (Now Sri Lanka). In 1877, 22 seedlings were sent from Ceylon to Singapore, where they grew strongly, and the technique of tapping was developed.
Prior to this, the trees had to be felled before the latex could be extracted.
Latex is often described as the sap of the Hevea tree. This is not an accurate description. The sap runs deeper inside the tree, beneath the cambium. Latex runs in the latex ducts which are in a layer immediately outside the cambium.
Too much damage to the cambium, and the tree stops growing and stops making latex.
It starts its journey when the tree is tapped. Trees are rarely tapped more often than once every two days.
At each tree a sharp knife is used to shave off the thinnest possible layer from the intact section of bark. The cut must be neither too deep, nor too thick. Either will reduce the productive life of the tree. This starts the latex flowing, and the tapper leaves a little cup underneath the cut.
The tapper must add a stabilising agent to the cup. Usually this is ammonia, which prevents the latex from coagulating.
The tapper returns a few hours later and collects the stuff in the cup.
When latex is required – which covers about 10 percent of all NR produced – the material is gathered on the tapper's return journey, poured into containers and delivered to a processing station where it is strained and concentrated. At no stage in the process is the latex heated. This means most of the proteins remain in the latex.
The latex goes into a centrifuge to remove some of the water, and increase the rubber content of the latex. After centrifuging, the material is known as latex concentrate, and contains roughly 60 percent solid rubber and 40 percent other stuff (water, proteins etc.).