18 



THE INDIA RUBBER WORLD 



[October 1, 1912. 



The nature of mineral rubber being asphaltic means that they 

 are all of them hydrocarbon compounds. It is a well known 

 fact that any hydrocarbon will, when subjected to sufficient heat, 

 throw ofT gaseous matters. If the temperature at which a com- 

 pound will throw of? these gaseous products is below that which 

 is used in the vulcanization, it will be detrimental in such com- 

 pound. As these gases must of necessity secrete themselves 

 somewhere, and if the compound is one which is vulcanized in 

 a mold or any air-tight compartment, it naturally follows that 

 the gas will cause the compound to become porous. 



Now taking the same class of compound and using a hydro- 

 carbon therein that would not show any gaseous products at or 

 below the temperature at which the compound was vulcanized, 

 this result would not follow. 



Again there are those so-called mineral rubbers which are pro- 

 duced by the treatment of asphalts segregated in the fractional 

 distillation of petroleums. Subsequent to the segregation they 

 are treated to a heating and drying process, by pumping in a 

 current of air; sometimes accompanied by steam. This is pumped 

 into the com- 

 pound in the 

 process of the 

 so-called oxidi- 

 zation, or drying 

 up of the com- 

 pound. It is a 

 well established 

 fact that this 

 class of hydro- 

 carbons, exposed 

 to atmospheric 

 conditions do not 

 have the wearing 

 qualities that the 

 asphalts have, 

 which have not 

 been thus treat- 

 ed ; the theory, 

 which is founded 

 on practice, be- 

 ing that the life 

 of an asphalt de- 

 pends upon how 

 long it will re- 

 sist o.xidization 

 when exposed to 

 atmospheric con- 

 ditions. The 

 treating of the 

 asphalt for the 



purpose of oxidizing it, prior to use, simply shortens the life of 

 the same proportionately to the amount of oxygen which it 

 takes in and the amount of oxygen it takes to destroy it. 



It would follow that in the use of these qualities of hydro- 

 carbons in rubber compounds, the same result would be obtained, 

 i. e., a rubber compound which contained a mineral rubber, pro- 

 duced by the oxidizing process, would have a shorter life than a 

 rubber in which a mineral rubber was used which had not been 

 previously treated by an oxidizing process. It would therefore 

 seem reasonable for the rubber manufacturer to know and 

 determine the quality of his hydro-carbon as definitely as he does 

 the quality of his reclaimed rubber or other ingredients used in 

 his compounds. 



There are other grades of hydro-carbons which contain various 

 quantities of paraffine and sulphur, such elements being contained 

 in the natural asphalt which do not determine themselves until 

 sufficient heat has been applied for decomposition to take place 

 and free these elements. 

 It is of importance to know at what point such decomposition 



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takes place, as, should it take place at a temperature less than 

 that used in the vulcanization of a rubber compound, wliereiii 

 such hydro-carbon was used, it would have a very detrimental 

 effect upon the compound, and unless a maiuifacturer does know 

 at what point this decomposition will take place, he cannot de- 

 termine what this effect will be except through the channel of 

 experimenting. If he knew, he would then be able to determine 

 wherein he could use the hydro-carbon safely. 



Tliere is no doubt that this so-called mineral rubber can be 

 used advantageously when properly applied, and there is no 

 reason why a rubber manufacturer should not give to tlie pro- 

 ducer of mineral rubbers the same closse attention which he 

 does to the producers of the different grades of rubber, and 

 insist that the producer of the hydro-carbon give him delinite 

 information relative to its constituents. 



It is true that many of the rubber factories today have well 

 equipped chemical laboratories, but it is doubtful if there are 

 any of them that are equipped to properly test a hydro-carbon. 

 Chemical analysis means but little in this class of materials, the 



important ques- 

 tion being what 

 this chemical 

 process will do 

 under conditions 

 essential to use 

 in the manufac- 

 turing of rubber 

 compound. 



Too many 

 mineral rubbers 

 are sold based 

 solely upon the 

 question of price, 

 and too many 

 rubber manufac- 

 turers have at- 

 tempted to use 

 them from this 

 same standpoint, 

 subsequently de- 

 crying them be- 

 cause they did 

 not do all that 

 w a s expected ; 

 whereas if they 

 had known what 

 the action would 

 be w li e n the 

 mineral rubber 

 received the 

 trentmenl given it, they would have known as well that tiiey 

 could not secure satisfactory results. 



There is probably no other place in the world where hydro- 

 c:.rbons are given the close study which they receive in the 

 manufacture of the so-called rubber roolings. The surface of 

 these roolings is composed of a compound purely asphaltic. 

 and its life depends on the quality. 



This class of manufacturers must of necessity know what 

 the constituent elements of the compound are, and what are 

 its actions when treated under the processes which they use. 

 This means that practically every asphaltum that they use, is 

 tested by a fractional distillation process either in their own 

 laboratory, or by the firm which supplies them with the material 

 being able to satisfy them that their reports relative to the 

 products are correct. 



If the rubber manufacturer will insist upon having a knowledge 

 of his hydro-carbon along these same lines, he can without doubt 

 use various grades of them advantageously in the different quali- 

 ties of compounds which he manufactures; but for him to say 



