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THE INDIA RUBBER WORLD 



[May 1, 1920. 



The Rubber Trade in Great Britain. 



/)'v Our Regular Correspondent. 



BUSINESS in practically all ck-partnicnts of the trade contin- 

 ues to be brisk enough as far as the order book is con- 

 cerned. This, howe-ver, does not mean that everything is 

 proceeding smoothly and that there are no worries to contend 

 with. In fact, if all troubles were enumerated it would form 

 a long list, what with labor demands for higher wages and 

 shorter hours, the rise in the price of textiles, transport diffi- 

 culties, etc., to say nothing of the impending levy on war wealth. 

 Judging by resolutions recently adopted by certain workers' 

 unions it would seem that the day wage in most industries will 

 be replaced by the piece-work system. This should tend to in- 

 crease output, which on the day wage system usually remains at 

 the level of the slowest worker. 



This year has been remarkable for the appeal to the public 

 to invest in all sorts of industrial concerns which, owing to the 

 increased expense of commodities and wages, require a larger 

 capital to carry on. To date — the middle of March — there has 

 been an issue of about one hundred millions, of which about 

 fourteen million pounds was for the rubber trade, including 

 eight millions issued by the Dunlop Rubber Co., Limited. Un- 

 derwriting has been easy to obtain as the public seems prepared 

 to go in for everything which offers. This pace, however, cannot 

 be kept up and we may expect to see a considerable slowing 

 down. 



THE PROOFING TRADE. 



The use of coal tar products as petrol substitutes is on th'j 

 increase, owing to the rise in price of petrol, and the solvent 

 naphtha position is causing perturbation in the minds of proofers. 

 So far, not much has been done in the way of installing re- 

 covery plants, but engineers are quite alive to the possibilities in 

 this direction and a good many specifications are now before 

 proofing firms. Of course the initial expense is now somewhat 

 heavy and, moreover, specifications and estimates are not worth 

 much nowadays, as they all contain clauses to the effect that 

 extra may have to be charged if materials and labor go up be- 

 fore the work is completed. However, the matter of the in- 

 stallation of recovery plants is receiving more serious attention 

 now than has ever been the case in the history of the proofing 

 trade. 



Now that business has got back into normal channels there 

 is plenty of competition for the work given out and proofers are 

 not finding it too easy to get customers to agree to the high 

 prices now ruling on account of the increased costs of materials, 

 except rubber. Many firms are still busy on old contracts, and 

 where they have covered themselves for cloth they are all right 

 and are, of course, in a very good position if they have excess 

 cloth in stock at old prices. Those who have to buy their cloth 

 at to-day's prices can only compete w'ith the utmost economy 

 in other directions, hence they do not turn a deaf ear to the 

 advocates of naphtha recovery. The rain coat business is de- 

 cidedly flat and in some cases where there is a stock of cloth 

 rain-proofed but not cut up, it is being turned over to the proof- 

 ers to be rubbered where they are found willing to take the 

 business on. 



DETERMINATION OF SUBSTITUTE IN RUBBER. 



-^ communication on this subject has recently been published 

 by P. Dekker, of the Netherlands Government Rubber Institute, 

 at Delft. There will be many rubber analysts who will agree 

 with his statement that the determination is by no means so 

 easy as is often supposed. One cause is the incomplete abstrac- 

 tion of the substitute by alcoholic potash, and another is the 

 fact that substitutes have van'ing composition, this being more 



pronounced to-day than it was ten or twenty years ago. It 

 should be noted that the alcoholic potash extraction test, as laid 

 down in British Government specifications, is not a process for 

 the estimation of substitute so much as the determination of 

 organic matter not rubber, and as the acetone extract is also 

 taken into account it does not matter if 50 per cent of the 

 substitute goes into the acetone extract. In the case, however, 

 of a commercial analysis, where the object is to ascertain the 

 amount of substitute used, the proportion soluble in acetone is of 

 prime importance. No recognized correction can be made for 

 this, as the amount soluble in acetone varies within such wide 

 limits. Especially is this the case with brown substitutes con- 

 taining non-oily matters, such as paraffine wax. Mr. Dekker 

 experimented with a brov^n substitute containing 38 per cent 

 soluble in acetone. In my experience the figure has varied from 

 15 to as high as 70 per cent, though the latter figure may be 

 considered as exceptional. 



An interesting part of the paper refers to the determination 

 of substitute in the presence of asphalt, and it is shown that 

 the varying amounts of asphalt dissolved by acetone and al- 

 coholic potash entirely vitiate any attempt to gage the amount 

 of substitute dissolved by the same solvent and the author 

 comes to the conclusion that the determination of substitute is 

 not feasible in rubber compounds containing asphalt. As the 

 two are but rarely to be found in the same rubber compound, 

 the matter is not of great importance. 



The method he advocates for determining substitute in rub- 

 ber is to add to the alcoholic potash extract the acetone extract 

 minus rubber resins and sulphur, and to call the combined ex- 

 tract substitute. The chief draw-back to this conclusion seems 

 to be in the fact that where paraffine wax is present it is im- 

 possible to say whether it was used in addition to the ordinary 

 quality substitute or whether it formed a component part of 

 the substitute. Of course, if only the fatty acid, dissolved by 

 alcoholic potash and the fatty portion of the acetone extract 

 are added together and returned as substitute, a correct figure 

 is obtained for substitute as commonly understood, but not 

 necessarily for the commercial substitute as used by the rubber 

 manufacturer in his formula. 



PEACHEY'S NEW VULCANIZATION PROCESS. 



Peachey's process has been patented for most parts of the 

 world, the British patent being No. 129,826.' and its exploitation 

 is in progress by strong financial interests in England. It cer- 

 tainly does not lack the element of novelty as so many rubber 

 patents do, and its advent cannot fail to excite great interest 

 among rubber chemists and manufacturers. Stated briefly, the 

 vulcanization is effected by sulphur without the aid of heat, 

 and therefore certain organic fillers and a wide range of coloring 

 matters, the use of which has hitherto been barred, may be util- 

 ized in vulcanized rubber goods. The sulphur is got into the 

 rubber by employing the well-known inter-action of sulphureted 

 hydrogen and sulphur dioxide gases, which leads to the forma- 

 tion of free sulphur. Rather surprisingly, this sulphur acts upon 

 the rubber to vulcanize it in the cold. If a solution, say a 10 

 per cent solution of raw rubber in benzene, is saturated with 

 sulphur dioxide and is then mixed with another similar solution 

 saturated with sulphureted hydrogen, a jelly is formed after the 

 lapse of a short time and on evaporation of the solvent the rub- 

 ber is found to be well vulcanized. 



