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THE INDIA RUBBER WORLD 



[January i, 1910. 



Growth of the Rubber Reclaiming Industry. 



By Wilmer Dunbar. 



THE reclaiming of rubber from waste or scrap material has 

 made remarkable progress within the past two decades. 

 There is hardly any other branch of the business in which 

 so large a rate of growth has been shown. The improvement 

 in processes has been marked ; the extent of the business has 

 developed wonderfully; and the use of the product has increased 

 more rapidly than the consumption of crude rubber itself. The 

 reclaiming of rubber as a practical proposition originated in 

 America, and here is first developed to important proportions. 

 Naturally the use of reclaimed rubber was first adopted here, 

 while manufacturers in Europe were depending largely upon 

 substitutes. Today the use of reclaimed rubber has become uni- 

 versal in the industry, large plants for the purpose having been 

 installed in Europe, in addition to the product of which an im- 

 portant quantity is exported yearly from the United States. 

 Only recently a Japanese manufacturer has been making inquiries 

 in this country with reference to having a reclaiming plant built. 



The reclaiming business can be divided broadly into three 

 groups — the mechanical, the acid and the alkali processes. 



First in the order of development, and a process still largely 

 used, is that known as the mechanical, in which the old rubber 

 is first ground to a fine powder, and if fabric is present it is 

 blown or sieved out by the use of compressed air or screens. 

 It is then mixed with a given percentage of oil and devulcanized, 

 after which it can be put on a mill and sheeted or batched out. 

 In this description of the process for reclaiming rubber by me- 

 chanical means, probably, belongs the first attempts at reclaiming 

 old rubber scraps, which was by the use of water, the rubber 

 first being finely ground or shredded and then put into pans 

 filled with water and either boiled or put in a devulcanizer. 

 With some grades of old rubber this process was fairly suc- 

 cessful, although with the rubber then in use, which was as a 

 rule harder and, therefore, less easily acted upon than would be 

 the case with the present knowledge of compounding, it was not 

 extensively used. The next step was to use the finely ground 

 rubber in the batches while the mass was being mixed on the 

 mill and this is still being done very generally. The next 

 attempt at reclaiming, and this was especially true of old boots 

 and shoes, was to grind the stock to a fine powder, canvas and 

 all, and then mixing with a certain percentage of oil and devul- 

 canizing the entire mass, after which it could be batched or 

 sheeted out on a mill, although by many users no attempt was 

 made to do even this. 



Next in order of development is what is known as the acid 

 process. In this the rubber containing canvas is first cracked 

 in fine shreds and is then put in an acid tank, containing a bath 

 consisting of sulphuric acid and water. The stock is boiled in 

 the acid and water long enough to remove the canvas, after 

 which the rubber is washed in clean water to free it from the 

 surplus acid. It is then dried and sometimes ground to a powder 

 and run over a magnet to remove the iron, and by some manu- 

 facturers is run through what is known as a "rifHer" — a long 

 trough, containing obstructions through which a stream of water 

 is running, which contains the rubber, and the obstructions are 

 supposed to remove the sand and other metallic particles which 

 the magent does not remove. After the rubber is ground and is 

 ready to be used, it is mixed with a given amount of oil and 

 devulcanized. after which it is sheeted or batched out and by 

 some manufacturers run through mill refiner with a knife, and 

 by others through a strainer similar to a tubing machine. 



Third and last in the order of development is the alkali process, 

 in which the rubber and attached canvas is subjected to a treat- 



ment with caustic soda and water. Some of the apparatus for 

 the alkali process is very elaborate, although manufacturers are 

 beginning to use simpler methods than formerly. After devul- 

 canization, the old rubber is washed to free it from the alkali, 

 and after drying is then sheeted and refined in the same way as 

 described in connection with the acid process. 



In describing thus briefly and incompletely the reclaiming 

 industry, in which so many millions of dollars are invested, and 

 by which so many thousand tons of reclaimed rubber are pro- 

 duced, it seems proper to say that were it not for the use of this 

 reclaimed material, many rubber articles in common use would 

 be beyond the reach of people in ordinary circumstances. 



Reclaimed rubber is largely used in the boot and shoe trade, 

 in mechanical goods, and for insulated wire. Though not largely 

 used by the druggists' sundries trade and in the manufacture of 

 automobile tires, it is safe to predict that it will be used largely 

 by both in the near future, for experiments have already been 

 made by some large manufacturers along these lines and with 

 a great deal of success. 



It is impossible to state with any degree of accuracy the amount 

 of reclaimed rubber used in the United States, as many manu- 

 facturers do their own reclaiming, and the way in which the 

 old rubber is collected makes it absolutely impossible to do 

 any more than guess at the amount. There are people in the 

 trade, however, usually well informed, who estimate the amount 

 of reclaimed rubber used as twice the weight of new rubber. 



Yet the reclaiming of old rubber is in its infancy, as well as 

 its use in rubber goods, and it is destined to be the most neces- 

 sary feature of the rubber industry of the world, next to the 

 production of new rubber. The trade is coming every year more 

 and more to recognize its importance. After several attempts at 

 a permanent organization, a Rubber Reclaimers' Club has been 

 formed, which has systematized the business very much, and cor- 

 rected many abuses, especially in relation to the gathering of 

 old rubber. 



THE SINGAPORE RUBBER WORKS. 



THE Nederlandsche Gutta-Percha Maatschapii < Netherlands 

 Gutta-Percha Co.) have published a detailed report concern- 

 ing the business year 1908, in regard to the company's operations 

 in Singapore. The gutta-percha works, for making gutta-percha 

 from leaves, are located at a distance of 45 minutes (riding dis- 

 tance) from Singapore and measures 60x48 meters [=196 x 157 

 feet]. The management considered it necessary to have the 

 works inspected by one of the members of the board of director* 

 residing in Holland, and the same reports that the machinery 

 is in good condition. Operations in the works were started in 

 July, 1008, but the report states that it would be impossible to 

 operate the plant regularly and continually, the supply of leaves 

 being too irregular. The india-rubber factory, adjoining the 

 gutta-percha works, are also stated to be in a position to produce 

 a sufficient amount of goods for meeting all the demands that 

 could be made upon it at the present time. The company manu- 

 facture in their rubber factory tires for jinrikshas, gharries and 

 the like; mats and other automobile accessories and hose. The 

 director reports that the manufacture of these lines of goods is 

 carried on in a satisfactory manner. It was not considered neces- 

 sary to make any addition to the present stock of molds. 



The index to Mr. Pearson's book. "Crude Rubber and Com- 

 pounding Ingredients," will be sent free by mail on request. 



