April 1, 1914.] 



THE INDIA RUBBER WORLD 



379 



The India Rubber Trade in Great Britain. 



By Our Regular Correspondent. 



RECLAlMlil) KUIiUliR. 



UNDER the title of "Reclaimed Ruliber vs. Plantation Rul)- 

 l)cr," Mr. Maclarcn, who is a director of several rubber 

 plantation companies, contributed a lengthy and inter- 

 esting article to the "India Rubber Journal,'' of Fel)ruary 7. 

 No doubt many of my readers have seen it. and I shall not 

 attempt to refer to it here in detail. 1 should, however, like 

 to say that opinions expressed in my presence are by no means 

 unanimous as to his figures and general deductions. His estimate 

 that the amount of rubber in the reclaimed manufacture is 

 equivalent to about 56,000 tons is considered by some as too 

 low, 80,000 tons being suggested as nearer the mark. 



Reclaimers do not regard the future with much apprehension. 

 Old rublier, they contend, w'ill always be collected as old iron 

 always has been, whatever the market price may be. Again, 

 the greater the amount of new rubber used, the greater will 

 be the tonnage of scrap collected ; and as regards the selling 

 price of reclaimed, it is pointed out that prices will conform to 

 the market price of raw rubber and scrap. Thus motor tires, 

 which not long ago cost f40 per ton, are now being bought at 

 il8 to £20 per ton, and the selling price of reclaimed has been 

 reduced accordingly. Probably because the total amount pro- 

 duced is small, Mr. Maclaren does not refer to certain brands 

 of reclaimed rubber which correspond very closely to new raw 

 rubber, having been derived from unvulcanized scrap, as also 

 from scrap containing only one or two per cent, of mineral and 

 slightly vulcanized. 



If what I hear is correct a prominent reclaiming firm in Eng- 

 land is contemplating the erection of additional works at an- 

 other place in the country, wliich hardly looks as if it expected 

 an early collapse of its business. Other firms report a steady 

 business, though they are not as busy as they have been. Al- 

 though motor tires have fallen in price, other classes of scrap 

 show practically no reduction, this applying especially to reds, 

 grays and cab tires, these last still coming on the market in 

 spite of the growth of the taxicab in all large towns. 



ANALYSIS OF RUBBER INSULATION. 



The preliminary report of the joint rubber insulation com- 

 mittee, appointed by American manufacturers and users, is of 

 special interest to rubber analysts generally, and I may perhaps 

 be afforded space to make one or two observations thereon. It 

 must not be overlooked that the carefully defined details of 

 analytical work have for their main object the determination 

 as to whether or no the sample under analysis conforms to a 

 specified quality. There are certain limits given for the acetone, 

 chloroform and potash extractions, etc., and if these limits are 

 exceeded, the sample is presumably condemned. This sort of 

 work is always simpler than stating the actual composition of 

 an unknown sample. At the same time those who are frequently 

 confronted wMth the latter work, or rather problem, will no 

 doubt find the new analytical scheme a decided aid in their 

 labors. Perhaps in the case of those firms to which these speci- 

 fications apply the time occupied in analysis is of no great mo- 

 ment, but for factory use, or for the ordinary consultant, a 

 string of processes, each taking up many hours, is rather a 

 serious matter. A rubber analysis which occupies three days 

 is apt to defeat its main objective except in legal cases, or 

 where large and important contracts are concerned. 



It is interesting to note that the old method of estimating 

 the rubber by difference is adhered to, the various direct methods 

 being evidently considered insufficiently reliable. The difficult 

 problem of getting at the amount of asphaltic bodies has been 

 tackled to a limited extent. Extraction with chloroform, after 



the acetone extraction, is the procedure adopted, though this is 

 only meant to show the absence of asphalt, and does not claim 

 to give its exact quantity if present. A small amount of 

 extract is allowed as the chloroform is known to dissolve some 

 rubber. The inaccuracy of all these extraction methods for 

 asphalt pitch or mineral rubber lies in the fact that a consider- 

 able and variable proportion is always dissolved out by the 

 acetone, and unless allowance is made the figure obtained by 

 the asphalt solvent used later on is always too low. For the 

 determination of mineral matter ashing the sample is not recom- 

 mended, solution of the rubber and filtration off of the sediment 

 being the specified procedure. No doubt w^hcre time is no ob- 

 ject this is the better method, and in certain cases the only 

 method which can be adopted with any pretense to accuracy. 

 The more rapid ashing method, however, can, in capable hands 

 at any rate, for many rubber compounds be made to give suf- 

 ficiently accurate results, and it will still continue, I imagine, in 

 general use. By the qualifying clause, "capable hands," I mean 

 one who has a sufficient knowledge of rubber manufacture to 

 enable him to apply certain necessary corrections to the figures 

 obtained. 



Another, and a long standing problem, of ruliber analysis is 

 left unsolved ; that is the determination of lampblack. In the 

 present scheme carbon is to be tested for by the presence of a 

 black color on treatment with nitric acid, but the test is not 

 put forward as a quantitative one. Special attention is drawn to 

 the preparation of the sample for analysis. This is a more 

 important matter than is generally supposed, and the recom- 

 mendation to pass all the material through a definite mesh sieve 

 before analysis is a procedure which should be generally fol- 

 lowed. 



FINE HARD FROM EASTERN PLANTATIONS. 



More trouble seems in store for Brazilian finances — that is, 

 supposing that the Wickham Hard Cure Process comes up to 

 the confident anticipations of the promoters of the company 

 which is now engaged in exploiting it. I have not been fortunate 

 enough yet to obtain a sample of the smoked rubber, but from 

 what I have heard there is not exactly a unanimous opinion 

 among manufacturers as to the equality of this rubber with 

 Brazilian Hard Cure. Moreover the suggestion has been made 

 in certain quarters that Mr. Wickham, who is universally re- 

 spected, has lent his name and influence rather too readily to 

 the city element. Presumably the patent is a sound one, though, 

 as the treatment of rubber latex with wood smoke is of course 

 well known, the novelty must lie in the particular mechanical 

 contrivance for carrying it into effect. 



Briefly described the Wickham machine consists of a vertical 

 disc with a flange three or four inches wide, the liquid latex 

 being allowed to drip on the interior of the flange at a uniform 

 rate. The disc is revolved at about 90 revolutions per minute, 

 the centrifugal action causing the latex to spread, and carrying 

 it in a thin film round the interior of the flange, to where a 

 jet of hot smoke is allowed to impinge upon it. The resulting 

 effect is a continuous process of curing in the .'\mazonian 

 fashion, superimposed thin films of rubber being formed. When 

 a thick enough film has been formed it is removed and pressed 

 for transport. Prima facie, this process, which is quite distinct 

 from the Byrne patent process of smoking the already coagu- 

 lated latex, should give rubber equal to the Brazilian — always 

 supposing that the actual composition of the latex from the 

 youthful eastern trees is identical with that yielded by trees 

 of far greater age. Personally I am not at all satisfied that 

 the latices are similar, and if they are not I imagine that it is 



