Why Today's Educated Consumer Chooses Natural Rubber:
Hevea milk contains an antibacterial substance that is a natural dust-mite repellent.
Natural rubber manufactured from this unique substance also breathes perfectly and is not temperature-sensitive. As a result, it never feels moist or warm to the touch.
Superior air circulation creates an environment which naturally prevents mold and mildew growth.
Retention of shape and firmness for even support year in and year out.
Superior durability and elasticity for mattress longevity.
Flexibility combined with stability for continuous sleep comfort.
Excellent natural heat and moisture regulation.
Natural rubber is an ideal choice for mattresses due to its inherent qualities of flexibility and resiliency with minimal compaction, combined with superior comfort and support. As with organic cotton and wool, natural rubber contributes to excellent heat and moisture regulation as well.
Sources:Sleeptek, Azom, High Beam Encyclopedia, UCLA Botanical Garden
A natural substance that had been used for centuries, Caoutchouc comes from the Indian word “cahuchu,” which means “weeping wood.” About 1770, the “cahuchu” was employed by artists for erasing black-lead pencil marks—the name "rubber" comes from the use of the natural substance as a pencil eraser that could “rub out” pencil marks. Natural rubber is harvested from the sap that oozes from the bark of the tree Hevea brasiliensis.
About our manufacturers, sourcing, harvesting and processing of organic cotton:
SLEEPTEK, the manufacturer of the Green Sleep and Oasis lines, uses only the finest grade A natural rubber for the support core at the centre of its mattresses.
Natural rubber mattress cores start as liquid latex, the sap or "milk" of Hevea brasiliensis, the common rubber tree is harvested by independent farmers in Northern Malaysia. These farmers have, for several years now, been perfecting their organic harvesting methods in cooperation with the National Rubber Institute in Kuala Lumpur. After many years of careful selection, the Malaysian plantation growers have succeeded in tapping Hevea milk that can be molded into mattress cores of varying degrees of firmness.
The trees growing in these North Malaysian plantations are selected for their high-quality Hevea milk production. No herbicides are used during the growing and harvesting process. Because the raw Hevea milk destabilizes when stored for too long, the milk is processed into rubber close to the harvesting plantations. In fact, by processing the raw Hevea milk on the day of harvest, the need for stabilization chemicals of any kind is avoided. Rubber milk harvested in the morning is molded into sheets by mid-afternoon, and those sheets are shipped to the Sleeptek Canadian mattress plant soon thereafter.
Having rubber manufactured where the tree's milk is harvested is both an environmentally conscious choice and an economically sustainable one. This method of production sustains the local economy, as jobs are created without depleting the natural resources.
A short history of natural rubber; the Hevea brasiliensis rubber plant is now grown on plantations in many wet tropical regions, but until the 1900s it was strictly grown in Brazil. European contact with the plant began when Christopher Columbus observed waterproof containers and watched ball games in Haiti. He returned from his second voyage in 1496, bringing the first rubber balls from the West Indies to Europe. There was, Spanish observers said, ‘nothing comparable in the world to the way that the balls bounced’. Previously only packed leather balls had been known in Europe, and this new rubber was a complete novelty.
Other New World explorers found rubberized items in Central and South America, but the source of this product remained completely unknown for a long time. In 1615, a book was published in which told that the natives obtained gum from trees. Rubber was used for waterproofing of clothing, shoes, and kitchen items. Finally in 1734, the French astronomer de la Condamine observed how natives collected and condensed the "juice" (latex) from the bark of a tree to produce rubber. The species then observed was probably the Panama rubber tree (Castilla elastica), which is a very common pioneer tree of forest succession and was then the rubber source for Central America and the West Indies. In his 1736 report sent back to France, de la Condamine called this product caoutchouc. The report on rubber making and the samples stirred great publicity in France and the rest of Europe, creating an immediate demand for rubber.
The name "rubber" was presumably coined in 1770 by the famous chemist Joseph Priestley (discoverer of oxygen), who realized that the substance could erase (rub out) pencil marks. But the uses of rubber were largely restricted to solid playthings and conversation pieces, because crude rubber had some disagreeable properties. First, Europeans had no solvent for rubber, so they could not change its form very well. Second, crude rubber was odorous, tacky, and perishable, and the hardness of the product fluctuated with temperature, being hard when cold and soft when warm.
The first innovative use of rubber was in 1823 by an English inventor (Hancock) and a Scottish chemist (Macintosh), who found that naphtha is a solvent of rubber. These investigators were able to dissolve crude rubber and then laminate a thin layer of rubber to a fabric, and thereby manufacture the first waterproof cloa--the raincoat, aka the macintosh. At the same time, "gumshoes" were imported to New England as footwear for seafarers; unfortunately, the shoes were too small for the Yankees, because they were shaped to fit smaller Amazonian, and not U.S., feet.
In 1839, Goodyear revolutionized the rubber industry by inventing vulcanization, which eliminated the disagreeable physical properties of rubber by combining natural rubber with sulfur and lead through a heat curing process. Henceforth, rubber products have been able to remain homogeneous under many different temperatures. The rubber industry got its biggest business boost by the development of tires, for bicycles and especially for automobiles. Dunlap marketed the pneumatic tire in 1888, and the automobile was invented in 1895.
During the 19th century, nearly all crude rubber came out of the jungles of Brazil from native plants of Hevea brasiliensis, although natural rubbers from guayule (Parthenium argentatum) and Castilla plus a few other plants were also used. All rubber is produced as a liquid latex in sacs or canals called laticifers, which are generally found in the phloem (inner bark). When the bark is cut, the white latex of Hevea escapes from the laticifers and can be collected in a cup. Natives formerly collected the latex and took it to their villages, where they made 200-pound balls of crude rubber. The ball was made by slowly coagulating the latex on a pole that was turned over a smoky fire. The acid from the smoke caused the latex to polymerize and thereby harden. Smoked balls were then floated downstream to market. Natives who did the work were very poor, but the "rubber barons" became extremely wealthy. In Manaus, Brazil, for example, which is located in the central Amazon, the wealthy marketers of rubber built elaborate cities, including a European-style opera house.
Rubber suppliers could not meet commercial demands in the mid-1800s; this need eventually led the British, then running a vast British Empire with one-quarter of the world's population, to search for a way to break the Brazilian monopoly. Sir Joseph Dalton Hooker, Director of the Royal Botanic Garden at Kew in England, and Markham of the (British) Indian Office, recommended the establishment of British rubber plantations in tropical Asia. To do this, seeds or living plants had to be smuggled out of Brazil. The seeds have a very short life, and several attempts to get the seeds to germinate in England failed. Finally in 1876, Henry A. Wickham, an English adventurer, succeeded in delivering 70,000 seeds of Hevea to the Kew Gardens for propagation, of which 2397 seeds germinated. From the Wickham seeds, 1900 plants went to Ceylon, and most of the rest went to the Singapore Botanical Gardens. From there Hevea plants were introduced to Malaysia, Sumatra, and West Java (only two plants). Wickham was knighted, of course, for his illegal activities.
The development of rubber plantations in British Asia was not an overnight success; until 1910, Asian production was essentially nil. However, over the 30-year period the British had studied and found ways to obtain maximum yields from Hevea, and the production eventually went into high gear and surpassed Brazilian production. One British achievement was the development of high-yielding, double-grafted plants. The British also devised ways of harvesting latex to maximize its flow by unclogging the laticifers through successive removal of bark tissue. The transport of Hevea to Asia was probably what really saved rubber production, because the plant escaped its fungus enemy. However, the plants Wickham took from Brazil (Tapajoz) were not as productive or disease-resistant as those from other areas upstream from Tapajoz.
Natural rubber can now be processed in stages. Bulk latex (liquid) is strained at a processing plant. Then gaseous ammonia is added, so that the latex can be shipped without the fear of coagulation. Coagulation can later be produced by adding formic or acetic acid.
Rubber plantations in Asia were seized by the Japanese in World War II; hence, the Allies frantically tried to establish New World plantations and to invent synthetic rubber. During the war, the U.S. Congress passed the Emergency Rubber Project Act to solve the rubber shortage problem. With this, government used lands in the western states for the production of rubber from another rubber-producing plant, the shrubby guayule, Parthenium argentatum. Much rubber was produced from guayule during the war. However, after World War II, production levels of both hevea rubber and guayule dropped, because U.S. chemists had developed (1944) synthetic rubber by polymerizing butadiene and styrene. Nowadays, much of the rubber that we use is synthetic. But because natural rubber has different polymer lengths and side chains and therefore different characteristics than synthetic rubber, some natural rubber is still added to products. Car tires have 12.5-28% natural rubber (higher in radial tires), truck and bus tires 50-75%, and aircraft tires 90-100%, whereas soft bicycle tires are synthetic only. The world still consumes about 4 million tons of natural rubber every year.