14 



THE INDIA RUBBER WORLD 



[October 1, 1913. 



The machine shown in Fig. 3, also made by David Bridge & 

 Co., is constructed after the Price patent and is similar in principle 

 to the machine described above. Instead of feeding the rubber 

 to the mandrel from a calender it is fed from a roll A and is 

 kept free from air by means of the roller B. It will be seen 

 that this roller is pressed down onto the rubber by the weighted 

 lever C, thus gaining a more solid mass entirely free from air 

 pockets. The same or a similar cutting apparatus D is employed 

 for shaping the tire to the required section to suit the mould. 



SOME RUBBER PROBLEMS. 



In his paper lately read before the Liverpool section of the 

 * Society of Chemical Industry Mr. H. E. Potts dealt with 

 various questions now engaging the attention of rubber manu- 

 facturers. He first gave some interesting particulars as to the 

 latex of Hevea Brasiliensis. Investigations as to the nature of 

 coagulation, he remarked, have not as yet reached a final stage, 

 although this subject is of extreme importance in connection 

 with the quality of the crude rubber to be produced. 



He furtlier treated in detail the difference between plantation 

 and wild Para rubbers, the latter seeming harder, more "nervy" 

 after rolling and, in many cases, more consistent in quality. 

 Among the causes to which this alleged superiority has been 

 attributed is the premature tapping of plantation Hei.'eas and 

 the use of acetic acid as a coagulant in place of smoking as with 

 wild Para. Byrne has, however, taken out a patent for smoking 

 plantation Para. 



With regard to testing rubber Mr. Potts urged that the present 

 custom of purchasing large quantities of crude rubber from a 

 small average sample was not an advisable method. He sug- 

 gested the establishment of a warehouse for all the arrivals of 

 plantation rubber, where experiments in vulcanization could be 

 carried out, the results of which, together with samples, being 

 accessible to the buyer. The manufacturer would thus be as- 

 sured of receiving a product which, under like circumstances, 

 would vulcanize in the same manner, and would be exempted 

 from the necessity of making new vulcanization tests of each 

 sample. In addition, it would be possible to ascertain the nature 

 of the factors which affect the quality of the crude rubber and 

 its vulcanization. 



Another subject dealt with was the chemical composition of 

 technically pure crude rubber. Under this head various 

 laboratory methods were discussed for the removal of the 

 protein. The constitution of rubber was then treated with 

 reference to the investigations of Harries and other experts. 



The problem of synthetic rubber was next discussed, Mr. 

 Potts distinguishing between the polymerization of isoprene into 

 rubber and the production of isoprene as the two stages in the 

 process. He further expressed the opinion that it was possible 

 to produce from isoprene a substance resembling natural rubber, 

 and that homologues of rubber could be obtained in the same 

 way. Oil of turpentine had been the original basic material, but 

 only had a yield of 10 per cent, in the first experiments, which 

 proportion has since been increased. Other substances had been 

 tried, Bayer of Ebcrfeld using Kresol and the Perkin group 

 fusel oil. The latter is now, however, dear. The best prospects 

 of success, Mr. Potts considered, lie with the process for the 

 production of isoprene homologues. He finally quoted the state- 

 ment of Dr. HofTmann, of Elberfeld, to the effect that a long 

 time would elapse before synthetic rubber became an article of 

 commerce. 



Next in order came the problem of vulcanization, the speed of 

 the process depending on the nature of the crude rubber em- 

 ployed and upon the method of vulcanization. If the co-efficient 

 of vulcanization ascends, the hardness of the vulcanized article 

 increases. Thus, it is added, the highest degree of vulcanization 

 represents ebonite or hard rubber. 



Reclaimed rubber is the last subject treated. In this connection 

 Mr. Potts states that it has so far been found impossible to 

 produce from waste rubber a substance equal to the crude 

 article, and equally free from sulphur. According to Hinrichsen 

 and others, a product containing a reduced proportion of bound 

 sulphur is obtained by treating the waste rubber with zinc and 

 with a mixture of benzine and alcoholic soda-lye. This conten- 

 tion has been criticized by Alexander. 



In conclusion Mr. Potts remarked that it is easy to distinguish 

 a good rubber article from an inferior one after several months' 

 wear. What the industry wants to know before compounding 

 and further treatment is whether a crude rubber is suited for 

 the manufacture of a given article. For this purpose it is 

 necessary to express differences in quality by chemical values. 



A NEW STICKING PROCESS. 



\ GREAT many processes are known that have for their ob- 

 •'*• ject the attaching of rubber to iron and steel. They are 

 all more or less faulty and only occasionally successful. When, 

 therefore, such an experienced and thoroughly practical rubber 

 manufacturer as John J. Voorhees claims to have a new process 

 by which a perfect adhesion between rubber and metal is at- 

 tained, respectful attention is at once accorded. What the 

 rubber trade has been vainly trying to do for the past forty 

 years is at last accomplished, if Mr. Voorhees says so; and that 

 is his statement. The Voorhees Co. calls the new process "Rub- 

 Steel Combination," and is offering it to all who are interested. 

 The illustrations accompanying show how thoroughly rubber 

 and metal may be joined by this process. 



The larger cut shows two flat pieces of steel, one-quarter of an 

 inch thick, vulcanized together witli a surface of rubber between 



Two Pieces of Steel With Intervening L.wer of Rubber. 



The Two Pieces Torn Ap.art. Showing the Rubber .-Xdhering 

 TO the Steel. 



them, one piece of steel projecting beyond the rubber in one 

 direction and the other piece of steel projecting beyond the rubber 

 in the other direction. The adhesion of the steel to the rubber 

 in this combination was given a very severe test, one steel end 

 being fastened in a vise while a large monkey wrench was ap- 

 plied to the other end, and it was necessary to exert a great 

 deal of force before the two were torn apart. 



In the other cut two steel discs are shown, vulcanized to a 

 round bar of rubber. The discs are furnished with rings, in 



Two Steel Discs Vulcanized to Round Piece of Rubber. 



which hooks are fastened, and in this way the tension is applied. 

 When the photograph was taken from which this cut was made 

 the rubber had been stretched to two and a half times its normal 

 length without any suggestion of parting from the steel. [The 

 Voorhees Rubber Manufacturing Co., Jersey City, New Jersey.] 



