March i, 1907. 



THE INDIA RUBBER WORLD 



179 



The India-Rubber Trade in Great Britain. 



liy Our Regular Corrcsfondent. 



IT is interesting to note that the system of vulcanizing in a very 

 short space of time at a high temperature, according to the 



Doughty patent, has amply fulfilled expectations. The patents 

 connected with the process are in the sole possession of the Dun- 

 lop company, and it is only in the various works of this company 

 HIGH in England, on the Continent, and in Aus- 



TEMPERATUHE tralia that the process is in operation. With- 

 VULCANIZATION. q^i Committing myself to the exact accuracy 

 of my figures, I may say that the actual time of vulcanizing is 

 three minutes at, I understand, 370° F. In the case of cycle tire 

 covers, to which it is practically restricted, the whole operation 

 of putting in vulcanizing and taking out occupies only five min- 

 utes, and in this matter of saving time the Dunlop company have 

 a decided "pull'' over their competitors. When the process was 

 first mooted there were plenty who prophesied disaster, but ex- 

 perience has shown that in the case of such comparatively thin 

 rubber as cycle covers, uniform vulcanization can be effected. 

 For thicker goods it is obviously unsuitcd, as the outside would 

 be burnt before the inside was vulcanized. I have no knowledge 

 as to whether the utilization of the high temperature process has 

 gone beyond the cover. Of course, in the patents owned by the 

 Dunlop company special reference is made to tires, the plant be- 

 ing designed to produce the cover in the exact form required 

 without its having to be shaped in a ring, as when cured in the 

 ordinary way in a flat mold or on a drum. Whether thft com- 

 bined application of high temperatures and short time generally is 

 protected by the Doughty patent is a point on which I am not 

 clear. 



Rubber gas tubing is largely used in chemical laboratories, and 

 in the majority of cases the quality is the point which is con- 

 sidered before the price. Very few chemical 

 operators know anything at all about the na- 

 ture of the tubing, and are entirely in the 

 hands of the laboratory furnisher. It is generally recognized that 

 the red tubing is superior to the black, chiefly because the latter goes 

 hard in cold weather and has to be thawed on commencing work on 

 a winter's morning. Evidently such tubing has only been cold cured ; 

 when a more desirable process has been adopted it can be made quite 

 equal to the red tubing as regards being affected by changes of 

 temperature. The other day, when in the laboratory of a chemist 

 holding a highly paid and important post, he told me that the 

 red gas tubing which he bought for best quality was not as good 

 as it used to be, soon becoming hard and inelastic. An inspection 

 of the tubing in question aroused my suspicions as to quality, 

 which were amply borne out by a rough analysis showing 68 

 per cent, of mineral matter. It is very unsatisfactory that tub- 

 ing like this should be sold as best quality, especially where the 

 purchaser goes to a dealer of repute and is willing to pay for the 

 best article. It is quite probable that the laboratory furnisher 

 knows no more about the nature of rubber goods than his cus- 

 tomers do. but as in various other businesses dealers are being 

 held responsible for their statements as to the quality it would 

 seem advisable for those who profess to sell difTerent qualities 

 of rubber goods to be able to distinguish between them. I am 

 not prepared to say what should be the exact limit of mineral 

 matter in best quality gas tubing, but the coloring 7natter 

 should certainly he antimony sulphide, and not red oxide of iron, 

 nor need there be any barytes present. As regards the diffusion 

 of coal gas through the tubing, it has been shown that this is 

 less in the case of moderately compounded rubber than in the 

 pure rubber and sulphur tubing; so. all things considered, the an- 

 timony red steam cured tubing, with a reasonable proportion of 

 zinc oxide, seems to be the ideal tubing. 



LABOHATORY 

 TTTBING. 



.•\n analyst writes to the editor of our London contemporary to 

 a.~k what substances he is to look for, as he has to make some 

 WHAT TO analysis of rubber goods. The editor in his 



LOOK FOR reply evidently shirks the amount of work 



IN RUBBER. involved in making out a list, and rightly ad- 

 vises the applicant to purchase a book on rubber. I think the an- 

 alyst in question is in for rather a tough time; evidently he knows 

 nothing about the trade and so will not be able to tell by the class, 

 quality, or look of the goods what substances may certainly be 

 taken as absent. If he tests religiously for all the substances he sees 

 iientioned in rubber literature as regular or suggested components 

 lit rubber goods he will have a herculean task calling for a fee which 

 liis client would doubtless consider beyond all reason. Without 

 ' inting at tiie prolial)ility ot iuccirrcct results being fibtained by 

 tiiose who undertake rubber analysis for the first time, there can 

 be no doubt of the advisability of employing an expert in such 

 analysis. It is strange how little trouble people will take in the 

 selection of a chemical consultant, though as in medicine so in 

 chemical analysis there are numerous specialists thoroughly fa- 

 miliar with one particular branch of chemistry and whose fees 

 are often less than those of men who do the work possibly for 

 the first time in their lives. It is impossible for a general analyst 

 to be up to date in the technology of all manufactures, or to lay 

 himself out to undertake every class of work, and the remedy 

 for ineflicient work is a greater recognition on the part of in- 

 dividuals of their own limitations. This obtains to some extent 

 at present, analysts engaged more particularly in one branch of 

 work having agreements with others to pass on to them certain 

 other classes of work. What is wanted is an extension of this 

 spirit of cooperation, which is undoubtedly advantageous to the 

 client and in many cases tends to relieve the inexpert chemist 

 from much mental worry. 



Of considerable interest is the table showing the resinous con- 

 tents of raw rubber in the December issue of this Journal, as given 

 THE RESIN by Mr. L. M. Bourne. The author remarks 

 CONTENT OF that the amount of resin in nearly every 

 iNDiA-RtlBBER. brand of rubber has increased during the last 

 two or throe years. Without wishing in any way to dispute this 

 statement, which prima facie is supported by the figures, it should 

 be borne in mind that analysts very often differ even when em- 

 ploying identical methods of procedure. I presume that the fig- 

 ures in question were got from the washed and dried rubber, and 

 as the rubber was weighed after precipitation from the benzol 

 solution by alchohol, the latter will contain as well as resin any 

 saccharine and nitrogenous matteres the rubber contained. I am 

 not prepared to say to what extent these other bodies would aug- 

 ment the resins when weighed with them, but in some brands, at 

 any rate, I am sure they are not negligible. Again, some rubbers 

 are very difficult to wash entirely free from fine sand, which un- 

 less special precautions were taken would be weighed with the 

 resins. However, leaving out of account any possible sources of 

 error in the analysis, how are we to account for an increase in 

 resinous constituents all round the globe in the same period of 

 time. Is the solution to be found in the higher prices prevailing 

 and a consequent rush to get the product to market, without the 

 usual amount of care being taken in the collection and transport? 

 Of course it must not be overlooked that in the case of a good 

 many rubbers great discrepancies are observable in the figures 

 given in the previously published tables, and it does not admit 

 of doubt that the resin in many brands of rubber varies con- 

 siderably not only in different consignments, but in parts of the 

 same consignment. In giving the name of a rubber it is also 

 necessary to say whether it has been graded. A striking figure 



