January 1, 1921 



THE INDIA RUBBER WORLD 



263 



The Problem of Gutta Percha Cultivation Solved 



MORE than twenty years ago gutta percha was successfully 

 extracted from the leaves of the Palaquium or gutta 

 percha tree. The product, "however, was very soft and 

 usually of a greenish color. It was not particularly valuable and 

 what promised to be a valuable process was therefore abandoned. 

 Taking a hint from the mechanical extraction of rubber from 

 dried shrubs and vines, experiments were undertaken by Dr. 

 Tromp de Haas in the Government Botanical Gardens in Java. 

 Dried leaves were used and the process is so far successful that 

 the gutta percha is now extracted in commercial quantities at a 

 profit. The fact that leaves from yoimg plants in tlic nursery, 

 as well as leaves frcm mature trees may be used, greatly in- 

 creases the available supply and indeed makes gutta percha cul- 

 tivation on a 

 large scale 

 possible. The 

 history of the 

 leaf extraction 

 e X p eriments 

 that follows 

 i s extremely 

 interesting. 



E X tracting 

 gutta percha 

 from the 

 leaves of gutta- 

 yielding trees 

 was first ac- 

 complished by 

 R i g o 1 e^ in 

 1892. He used 

 carbon bisul- 

 phide as a sol- 

 vent on finely 

 ground green 

 leaves. In 

 1896 Serullas' 

 obtained a 





sible, they do not scruple to mix any kind of leaves with those 

 from true gutta-yielding trees. 



The Tromp de Haas system is in vogue at the Experiment Sta- 

 tion at Tjipetir, Java, where tlie government has large gutta 

 plantations. Among the advantages of collecting leaves on a 

 plantation as against collecting in a forest, is the obvious one — 

 that coolies cannct mix valueless leaves with the useful ones. 

 So successful is the mechanical process that a second gutta 

 percha plantation lias already been started at Tjitarik, Preanger 

 Regency, Java. 



As for yields obtained by the mechanical process, it has been 

 found that a 10-year-old tree gives 15 i)ounds of dry leaves per 

 annum, from which is obtained 9 to 10 ounces of gutta percha. 



The annual 

 production by 

 this means at 

 Tjipelir i s 

 given as fol- 

 lows : about 38 

 tons in 1914, 

 47 in 1915, 51 

 in 1916, 67 in 

 1917, and 68 

 in 1918. 



While it 

 w a s a t first 

 thought that 

 the leaf gutta 

 percha would 

 Ik- inferior to 

 tli.it obtained 

 liy tapping 

 methods, the 

 process has so 

 far been im- 

 proved that 

 leaf gutta is 

 now used for 





. .ir^i-f- ■ 



patent' for a process in which hot toluol was used for extraction, 

 and the solution precipitated with acetone. Rosin oil was some- 

 times used instead of acetone but with indifferent success. 



The method named after Obach' is based (,n the soluliility of 

 gutta in petroleum ether at boiling point and the capacity to 

 precipitate when cooling at 15 degrees. 



All of the above produced a soft inferior product, and experi- 

 menters turned to mechanical extraction as the only solution, 



Mechanical extractors embody grinding mechanisms for pul- 

 verizing the leaves, rolls for agglutinating, sieves and water for 

 separating the woody matters from the gum. Guayule and grass 

 rubber extraction machines' such as the Abbe pebble mill, the 

 De La Cortc crusher, the Bridge crusher, the Guiget crusher and 

 the Valour crusher may all be adapted to this sort of work. There 

 are in use today two systems of mechanical extraction in the 

 Dutch East Indies, the Ledeboer, and the Tromp de Haas. 



The advantage of the mechanical process over the chemical is 

 that much more material can be handled at one time, making 

 the exploitation of an estate easier. The Ledeboer method is em- 

 ployed with success by the Nederlandsche Getah Perchafabriek, 

 Singapore. Natives collect the leaves in the forest and bring 

 them to the factory where the gutta is extracted. Since the na- 

 tives are anxious to bring in as large a r|uantity of leaves as pos- 



<'iUTT.\ Percha Nursery 



insulating submarine cables and many other purposes 



•Rubber Machinery. By H. C Pearson. 

 •British patent No. 11,166. 1892 



Paucs 257-270. 



TRADE-MARKED BRANDS OF BELTING. HOSE AND PACKING 



Rrcent rubber products of interest include an oil-resisting 

 packing, grain and ore-elevator beltings, and steam hose — all 

 made by the same manufacturer. 



"Volunteer" packing is a black, oil-resisting sheet packing, 

 specially compounded for use in contact with oil. 



"Kohincor" elevator belt is made of a special heavy duck and 

 high-grade friction rubber, the outstanding feature being the 

 unique way in which the rubber cover is anchored to the body 

 111 the belt. This is done by the application of a layer of coarse 

 meshed fabric known as "cider cloth" between the outside ply and 

 the rubber cover. The rubber compound used for the cover is 

 forced through the meshes of this cider cloth and thus anchored to 

 the body of the belt. The cover cannot blister or pee! ofT, thus 

 making the "Kohinoor" an ore-elevator belt suitable for severest 

 service. 



"Grainvey" is a very strong, rubber-covered belting, made of 

 closely woven, rubber-impregnated duck, especially for conveying 

 grain horizontally or on an incline, troughing easily without 

 spilling. 



"Elevay" belting is made of heavy, woven duck, impregnated 

 with rubber, and is intended especially for bucket elevators and 

 wherever extra strength is required. — The Diamond Rubber Co., 

 .Akron, Ohio. 



