August i, 1905.] 



IHE INDIA RUBBER WORLD 



867 



THE "GUAYULE" RUBBER PLANT— II. 



By Rudolf Endlich, Ph. D* 



T [IE industrial use of the Guayule plant dates only from 

 . the last few years, although several interested parties 

 have been experimenting with methods of extraction 

 during the past 15 years. The delay is principally due 

 to the fact that men possessing a thorough knowledge of the 

 rubber industry were not consulted. 



Only one Guayule factory, a branch of the Compafua Anglo- 

 Mexicana at Jimulco, near Torreon (Coahuila), is at present 

 in operation. The success thus far attained by these works has 

 recently caused the relatively small enterprise to be reorganized 

 into a new company with German capital, the Compania Ex- 

 plotadora de Caucho Mexicano, which is to enter upon the pro- 

 duction of Guayule rubber on a large scale. For this purpose- 

 four more factories have been planned, and will be located at 

 Gomez Palacio, at Torreon, at Saltillo, and at San Luis Potosi. 



A competing firm at Monterey (Nuevo Leon) has discontinued 

 the extracting of rubber before the enterprise had progressed 

 beyond the experimental stage. However, an American syndi- 

 cate has already completed the erection of its buildings at Sal- 

 tillo. A short time ago, moreover, the firm of E. Madera Her- 

 manos at Parras, commenced the building of a Guayule factory 

 on their ranch " EI Venado." 



The Cedros company, furthermore, whose plantation " Ced- 

 ros " has an area of 438 sitios (at 1755.61 hectares) on one- 

 seventh of which, or 60 sitios ( 105,366 hectares), Guayule plants 

 are said to grow, intends to establish a large plant on which 15 

 to 20 tons of crude material are to be handled daily. Two 

 American companies, the Continental Rubber Co. and a Cali- 

 fornia syndicate likewise intend to erect rubber works in the 

 neighborhood of Torteon. 



As the various methods of extraction are covered by Mexi- 

 can patents attempts have been made to extract the rubber in 

 foreign countries. It is stated, however, that only a few indi- 

 vidual shipments of Guayule plants have been made to Glasgow 

 and other ports. There is considerable doubt as to whether 

 this exportation will prove profitable, for not only the relatively 

 high freight rates of Mexican railways must be taken into con- 

 sideration, but likewise the probability of a future high export 

 duty, such as is at the present time being levied on other Mex- 

 ican crude vegetable materials. 



It is said that an enterprising genius has already undertaken 

 the production of Guayule rubber on a large scale of chewing 

 the bark, in the same way as toy rubber balls are now made in 

 the state of Durango. But even if we do not consider the fact 

 that this method can hardly prove successful, because it takes 

 a Guayule chewer two days to produce a toy rubber ball, the 

 enterprise is considered to be doomed to failure, as the persons 

 engaged in it are soon attacked by lockjaw and have to aban- 

 don the work. 



There are several more or less practical methods for extract- 

 ing the Guayule rubber. 



By the " Bergner " process (Mexican patent No. 2147, Aug- 

 ust, 1901) the plants are crushed in a Krupp crusher, and ground 

 in a ball mill (Krupp patent) until the larger part of the wood 

 is separated, and the rubber forms granules in conjunction with 

 the remaining wood particles. These are separated from the 

 wood either by sifting or by means of a suction device. For 



'Translated for The India Rui.ber World from Der Tropenpflanzer (Berlin), 

 IX Jahrg., Nr. 5. 



purifying the rubber, the granules are placed in an iron vessel 

 having a double bottom and heated by steam. As soon as the 

 mass boils a certain specified quantity of a sodium salt is added, 

 although this addition is not absolutely requisite. 



After boiling, the mass is transferred to a wooden vessel 

 where it is precipitated by the addition of cold water. After 

 removing the water, the mass is passed through drum sieves 

 having double bottoms. The rubber, which now contains only a 

 few particles of wood, is thereupon boiled with sodium hydro 

 oxide, and precipitated by a solution of calcium chloride. 

 This product is then compressed into thin flakes by means of 

 special devices. 



There are, however, simpler and more practical processes, in 

 which the crude material, ground to a fine powder, is mixed 

 with alkaline substances, and boiled in steam so as to separate 

 the particles of wood. 



These processes are probably similar to those used in the 

 manufacture of wood pulp, which consists in heating ciushed 

 wood, after a lo to I2' Baume solution of soda has been added, 

 during 5 to 6 hours with steam under a pressure of 6 to 14 at- 

 mospheres. This operation serves the purpose of dissolving the 

 binding substances, thereby liberating the minute particles of 

 wood. 



After the pulp has been removed, the mass is washed in 

 water and the alkaline substances are neutralized by diluted 

 acids. The rubber thus obtained is dried in the shape of large 

 flakes either in the sun or in rooms especially adapted to the 

 purpose. The residue, consisting of wood and bark, is used as 

 fuel for the steam boilers. 



The details of the rubber extracting processes are, of course, 

 kept secret by the manufacturers. It is said, however, that bi- 

 sulphide of carbon is used in the extraction process of the 

 American Guayule works at Saltillo. 



Guayule rubber extracted by the ordinary methods soon 

 blackens on the surface, while the inside of the flakes retains 

 its original greenish gray color. Its disadvantage consists in 

 the percentage of foreign substances it contains — 27 per cent, of 

 gum and aromatic matters, for instance, besides a variable 

 quantity of wood particles. The gum is especially harmful, as 

 the resinous quality of the rubber, which impairs its elasticity, 

 is attributed to its presence. 



The fact that Guayule rubber is easily vulcanized may be 

 called a good quality. Its smell, which is not disagreeable, is 

 due to the aromatic substances contained in the bark. 



By the introduction of a new process at Jimulco, Guayule 

 rubber has been so far improved that it usually contains no 

 more than 10 or at most 15 per cent, of foreign matter. This 

 rubber, which is very dark brown on the surface, but lighter in 

 color in the interior of the flakes, is at the present sold at a 

 price of more than 5 marks per kilogram, while only 3 marks 

 per kilo were obtained for it before the introduction of the im- 

 proved method. 



The rubber extracted at a chemical laboratory in Germany, 

 to which we have before referred, showed only 5 per cent, loss 

 by washing, and is said to have been appraised in Germany and 

 England at from 7 to 8.20 marks [per kilogram = 75'+ to 8334" 

 cents per pound]. If the method of obtaining a product of 

 such purity is practicable, it might become possible to use the 

 gum for technical purposes, after separating it from the rubber. 



