Decembkk 1, 1914] 



THE INDIA RUBBER WORLD 



131 



Rubber Solvents. 



WHILE the larger quantity of rubber is made into manufac- 

 tured products without having been brought into solu- 

 11-n. yet there are so many uses for rubber in solution 

 that the matter .if solvents becomes of great importance. Rubber 



being a hydrocarbon is soluble in the usual hydrocar! sol 



These ate usuall; those oluble in water and of an oily na- 



ture. A number of the more usual sulxents will he describi 

 thi I llowing paragraphs, beginning with those derived from 

 petri ileum. 



'i VENTS FROM PE1 Ri 



The petroleum oils are by far thi i oils in commi a 



and they tire solvents of rubber and are the most extensively 

 lass for that purpose. In defining petroleum ils 

 it is hard to make definite distinctions, for every oil is a mixture 

 .'i many separate chemical substances, and the names used to 

 designate them in the tradi and thi ti its used are indefinite and 

 the products of no two manufactui i in name or test. 



Petroleum oils consist in the main of hydrocarbons of several 

 -. and a large number of each series is found in each kind 

 i ii is taken from the ground. 



The first oils obtained from Pennsylvania and West Virginia 

 consisted i Is of the paraffine series exclusively having the 



ral formula, i' II 2. This series begins with marsh 

 with one carbon atom and goes up to the paraffine waxes with 

 many carbon atoms in each molecule, but each compound has 

 the same ratio of carbon .anil hydrogen as pointed out above. 



When this oil is distilled there first passes off a little marsh 

 gas which is dissolved in the oil, and following this i~ a serii 

 of products up to pentane, which boils at 36 degs. C, which are 

 mostlj lost, though products are sometimes made which will only 

 remain liquid under pressure and will rapidly evaporate in the 

 air. For example, there is a product known as cymogene which 

 boils at the temperature of melting ice and has a specific gravity 

 of 111) Be., and the next higher product is known as rhigolene, 

 which boils at al out 65 degs. F.. or ordinary temperature, and 

 lias a specific gravity of 100 Be. Sometimes a product known as 

 petroleum ether, boiling between thesi points, say about 50 degs. 

 C. is made. 



The next product obtained by distillation of Pennsylvania oil 

 is petroleum ether of 85 degs. Be., or gas machine gasoline, 

 which is very scarce now. It begins to boil at about 50 degs. C. 

 and contains some that boils at 1-0 degs C. This is sometimes 

 called benzine hut must not he confused with the coal tar benzol. 



Then there is a series of gasolines of different gravities and 

 boiling points. It was customary to use gasoline of 76 degs. Be., 

 but this product is now almost unobtainable, and that of 66 Be., 

 with a boiling point ranging up to 140 degs. C, is largely used. 

 After these products come the kerosenes, or burning oils, which 

 are not volatili enough to : '< used for solvents which have to 

 be later evaporated. 



The petroleum trade has clung to the use of the Baume hy- 

 drometer as a standard for grading oils, and usually no other 

 characteristic of the oil than its Be. gravity is used in the trade. 

 While all the oil used was of the paraffine series, the Re. gravity 

 was an indication of its relative volatility. This is now of no 

 value when other hydrocarbons an present 



When the oil of Pennsylvania became exhausted the oils of 

 Ohio assumed great importance, and these were found to differ 

 in many respects, While the ml of Pennsylvania was of a dark 

 greenish-red of from 49 to 34 Be., it was quite mobile and rathei 

 transparent, and had no impurities, such as sulphur or other 

 objectionable matter. Tin- ( Ihio -ils were found to contain large 

 quantities of sulphur and required special treatment, and there 

 were in them other hydrocarbons than the parafhncs. Now these 

 other hydrocarbons which correspond in boiling point with the 



fines have thi!' n nl vities and are usually heavier, 



so that a gasoline- or naphtha from them of a heavier gravity, 



say 70 Be., might have as low an average boiling point as one 



from Pennsylvania oil of 76 I i he products of the fields 



i Illinois. Texas, i Wyoming and Oklahoma came 



the market in turn, it was found that these oils consisted 



ries of hydi at ns and that in many cases 



they contained an asphalt base instead of a paraffine base. Many 



also contained much sulphur and some contained little or no 



ne or naphtha. 



These oils from the western part of the United States contain 

 1 i e amounts of oils of ries and some of the ace- 



tylen< oi aromatii I < latter, while having a dii 



m the paraffin- hen of the same boiling point, 



r rubber solvenl as the paraffine hydrocarbons, 

 and indeed often better. 



In purchasing petroleum naphthas, then-fore, at the present 

 time it is not sufficii i a naphtha of a certain gravity, 



but it must In- examined and tested as to its boiling point first. If 

 I I - gins to distil too low it is rather dangerous, as it will 

 he more inflammabh ; that is, the vapors given off at ordinary 

 temperatures will ignite easily and will carry a long way from 

 their source and will explode if they come into contact with a 

 >i flame. If there is much of a residue which distil- only 

 at a high temperature, the solvent will be too slow in drying 

 and the rul in it may remain tacky. The naphthas 



should also b( tested for their dissolving power, as it may vary 

 widely according to the hydi series present. 



Rubber manufacturers have been confronted for a number of 

 years with constantly rising prices for naphthas, and a constantly 



1 ii ■ grade has bei n rei eivi d. This situation had no connection 



with conditions in the rubber trade, but was due to the enormous 

 increase in demand for gasolines for motor vehicles. 



The demand created the supply, fi r it stimulated chemical ex- 

 periment, and methods have been invented whereby the heavy 

 oils can be "cracked" bj distillation under pressure to produce 

 light oils or gasoline, and this process is used on a very large 

 scale. Another influence that has lowered the price of gasoline 

 has been the discovery of oil in the "Cushing Pool" in Okla- 

 homa, where a well was drilled a short time ago that flowed 

 5,000 barrels daily, which was .allowed to go to waste for over 

 a week. This and other previous like samples of criminal neg- 

 ligence in wasting nature's lavish resources haw Compelled the 

 State of Oklahoma to make tin attempt to regulate the flow and 

 waste of oil. Gasolines have recently dropped from about 18 

 cents to 13 cents and even as low as 10 cents per gallon, and 

 disturbed European conditions will lower them still further, and 

 consumers should nm'. insist "ti being furnished a suitable 



naphtha. 



(' \KP.ON PI SU1 PHinE. 



This excellent rubber solvent is a chemical prepared by the 

 direct combination of carbon and sulphur under the influence 

 of high heat, and in America almost the entire aim tint i~ made 

 by heating by electrical means. Its solvent powers For i 

 an -ileal, and its great volatility makes it a most rapid dryer, 

 but it also makes it a most explosive compound. When mixed 

 with air and heated to 150 degs. C. it will explode, and cases are 

 known where it exploded by the friction of pouring it out of a 

 narrow glass tube. It must, therefore, be handled with great 

 care to prevent explosions. Its boiling point is 46 and 



its gravity is 1.29. It thet ighs 10 pounds per i lion. 



TURPENTINE AND TINE OIL. 



Turpentine is not much used as a solvent because of late years 

 it has' been high-priced. But still more- recently very low prices 

 have In en seen in this trade, and tin outlook is for low prices 



