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	1. Who discovered rubber? The Indians of Central and South America were the first to utilize rubber's unique properties. Christhpher Columbus watched them play a game called "Tlacahtlic", a vigorous cross between basketball and football, with the object of directing a rubber ball through a stone ring.   2. What was the first practical use of rubber? In England, Joseph Priestley, best known for his discovery of oxygen, noted that pencil marks could be "rubbed out" by the substance. From this early use, rubber derived its name.   3. What discovery marked the beginning of modern rubber technology? Prior to 1839, the properties of rubber were dictated by the surrounding temperature. During the hot summer, rubber was sticky and malleable, while it became hard and brittle in the colder months. This was finally remedied by the discovery of the process of vulcanization. A mixture of rubber, white lead and sulphur was dropped accidentally upon a hot stove. When it was removed, the material was no longer affected by temperature. Despite stretching, it always returned to its original shape. This process of vulcanization made it possible to use rubber in raincoats, overshoes, and eventually many other products, including tires.   4. What are the two types of rubber? The two types of rubber in common use today are natural rubber and synthetic. Natural rubber come from the rubber tree(Hevea brasillinsis). When a tree natures at the age of six or seven years, the latex is collected from a diagonal incision in the tree trunk. The tapping process does not effect the health of the tree and the tree wound later heais itself. Synthetic is made by man from petrochemical deedstocks. Crude oil is the principal raw material.   5. Where is natural rubber produced? Today more than 90% of the natural rubber supply comes from Southeast Asia .... Thailand, Malaysia, Vietnam. As rubber tree require a hot, damp climate, they grow only in the "Rubber Belt", an equatorial zone that stretched around the world. In 1876, the English, in recognition of the difficulties of securing quality rubber from the jungle, hit upon the idea of growing rubber on plantations. From their efforts, the cultivated rubber tree plantations of Southeast Asia and Africa have developed.   6. What accelerated the development of synthetic rubber? Synthetic rubber is developed in Germany during war in 1930's in order to make up for a deficiency of supply of natural rubber and for its functional defects.  The US was cut off from virtually all sources of natural rubber in the Pacific during World War II. In order to meet the nation's needs for this vital material, the government built synthetic rubber plants and the industry operated them. Synthetic rubber production jumped from 8,000 tons in 1941 to 820,000 tons in 1945. After the war, the government sold the plants to the industry.   7. What is a Natural Rubber Latex (NRL)? Latex is the protective fluid contained in tissue beneath the bark of the rubber tree, Hevea brasiliensis. Natural rubber latex (NRL) is a cloudy white liquid, similar in appearance to cows milk. It is collected by cutting a thin strip of bark from the tree and allowing the latex to exude into a collecting vessel over a period of hours.   8. What is a Dried Natural Rubber Process (DNR) ? This involves compressing the natural rubber at a high temperature and pressure. The plant proteins, responsible for the allergy, are denatured at these temperatures and pressures and therefore pose a lower risk than rubber made by the NRL process.   9. What is a Ribbed Smoked Sheets (RSS) This material consists of deliberately coagulated rubber sheets, completely dried using smoke. These sheets are then graded into three main grades according to their color, consistency and observed impurities. The purest is 1RSS , then 2RSS then 3RSS, 4RSS, 5RSS. RSS are used when extra tough (due to extensive cross linking) rubber is needed. Some applications are tires, tank liners, industrial products, etc.   10. What is an  AIR DRIED SHEET (ADS)? This product looks like RSS (Ribbed Smoked Sheet), but it is more transparent than RSS because it is processed in smokeless room. It is widely used in Colored Rubber Products.   11. What is a SKIM BLOCK ? Skim Block is the by-product from the natural latex production.    DATA CENTER > RICE > RUBBER > CANNED FOOD >