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THE INDIA RUBBER WORLD 



[May 1, 1915. 



What the Rubber Chemists Are Doing. 



a NEW \ i'i >RY. 



AX anonymous contributor signing himself "Rubber" in 

 I e i aoutchoiu & la Gutta Percha" of March 15. thinks 

 that vulcanization depends mi the colloidal state of rub- 

 ber, lli does not think Ostwald's absorption theory well 

 founded, but thinks Weber's combination theory better. 



Sulphur has seven or eight States, but the colloidal state is 

 the onh one adapted tor vulcanization, ami S s is the kej to 

 vulcanization. Pure gum ami sulphur will not vulcani i in 

 ol which Stevens and Weber are cited— but with resins 

 and proteins present the conditions are favorable. St 

 concluded that both resins and proteins had a role but did not 

 determine it. 



[f rubber and resin are heated together, hydrogen sulphide is 

 generated, as is shown bj the fact that paraft'nn and sulphur 

 produce hydrogen-sulphide. The insoluble matter in the rubber 

 ulphiir to SO : for example, free sulphur and litharge 

 heated in air, or an airy body as light magnesia, generate S< > . 

 The rub- of the re-ins, insoluble oxides and adjusters is to form 

 hydrogen sulphide and free sulphur. Various bodies transfer 

 S« to sulphur with formation of hydrogen-sulphidi and SO. 

 1 ate experiments on rubber show SO. diffused through gum. 

 Sulphurous-acid and hydrogen-sulphide will react to form water 

 and sulphur. The role of the earthj bodies is to absorb water. 



The transformation of S, into sulphur requires distribution 

 of certain methylene groups; instead of having all of di-methyl- 

 octadiene there is some octadiene. This reduces it from iso- 

 prene caoutchouc to butadiene. Heating in the open shows 

 hydrogen-sulphide, which proves decomposition of methylene. 

 As the heat of formation of hydrogen-sulphide is greater than 

 vulcanization, there is formation of free hydrogen-sulphide, 

 which is occluded, as can be determined by the acetone extract 

 reaction. The hydrogen-sulphide from the decomposition oi 

 methylene carries the combined sulphur of the rubber. The above 

 vulcanization theorj presents many novel points and probably 

 will not be accepted without considerable discussion 



\\ ENGLISH VIEW 01 CHEMICAL ANALYSIS. 



The "India Rubber Journal" of March 6, in an editorial, 

 criticizes adversely the practice of giving the chemical analysis 

 of rubber. I he Opinion is expressed that this is no criterion 

 either of its market value or its behavior. It is suggested that 

 the washing loss and usual physical attributes be stated. If the 

 technologists cannol agree what physical requirements an di 

 sired, they think the sooner that it is admitted the better. They 

 believe the chemical analysis should give the breaking strain, etc. 

 In this country a realization of the value of chemistry in the 

 rubber business is now shown by the general employment ol 

 chemists in all the prominent rubber works. A force of 40 

 ists is kept by one large company in a laboratory distinct 

 from any works, employed only on research work. 



While it is true that wi little yet about the chemistry 



of rubber that we cannot always determine by analysts the 

 of the sample, yet it is realized that many useful things can be 

 so determined. It is quite possible to determine by analysis 

 tin probable shrinkage, as this consists of water and dirt. Both 

 of these can be determined bj analysis, but the washing does 

 not always take out all the dirt, so that the analysis ran not 

 i with the washing. The analysis is perfect but the washing 

 is not. Tin- resin can also lie determined with accuracy and 

 its nature shown It is generally admitted that a large quantity 

 of resin is harmful to the rubber as stub, although its qualities 

 maj be desired for some work or purpose. The rubber itself 

 may also be determined as to amount but nol jO accurately as 

 to quality. Of late, however, it has been shown that small 



quantitii ol tin insoluble colloids found in some samples greatly 

 aiiect its quality— usually favorably. All this shows progress and 

 indicates that eventually we will be able to determine the value 

 of rubber bj analysis when we know more about rubber chem- 



SOME SYN I III II. r \ I ENTS. 



Matthews and Strange received British patent No. 24,790 in 

 1910 for tlu treatment oi synthetic caoutchouc with liquid SO* 

 This we have noted before, but patent No. 2,070, of 1914, has 

 been issued to them for a modification of the same process 

 and has seemed to attract considerable attention, as it has been 

 noted in many of our contemporary 



I'ritz Hoffman has assigned to the Synthetic Patents Co. — 

 which holds the American patents of the Beyer company, of 

 Elberfeld— a patent on treating certain synthetic rubbers with 

 piperidine or its homologues, and then vulcanizing with sulphur 

 as usual. 



EXPERIMENTS. 

 W. II. Caspari has contributed an article — published in the 

 "Journal of the Chemical Society" (England), for February, 

 1915, page 162 — which relates a number of experiments in pre- 

 cipitating rubber by alcohol or acetone from solution in benzol. 

 The experiments showed that one gram of caoutchouc when dis- 

 solved in 40 c.c. of benzol precipitated when 15 c.c. of alcohol 

 was added, forming 148 grams of precipitation. At higher tem- 

 perature, the necessary proportion of alcohol rises. Any little 

 moisture present produces precipitation much quicker. In 43 

 vols, alcohol tei 100 of benzine at 20 degrees C. caoutchouc was 

 practically insoluble. In Ml vols, acetone to 100 of benzine at 

 2(1 degrees ( . caoutchouc was practically insoluble. 



mi i ISION ON RE( LAIMING PATENTS. 



An important decision has been rendered by Judge Clark in 

 the federal court in Cleveland, Ohio, in a suit brought by the 

 Philadelphia Rubber Works Co. against the Portage Rubber Co. 

 for infringement of the Marks patent Xo. 635,141. 



It appears that in 1900 Arthur II. Marks assigned his patents 

 on reclaiming, which comprise what is usually known as the 

 "Alkali Process," to the 1 liamond Rubber Co. The Diamond 

 in turn assigned to the Alkali Rubber Co., reserving the right 

 of action and any awards in the suit against the Calumet Tire 

 & Rubber Co. then pending. The Alkali Rubber Co. assigned 

 to the Philadelphia Rubber Works Co. in 1911. 



The Portage Rubber Co, alleged first that the Marks patent 

 was invalid and secondly that it did not infringe, as it used the 

 Wildman and Christy process — patent No. 993,485. The de- 

 cision sustained the contentions of the Portage company on 

 both counts. 



Viewing patent Xo. 240,970 granted to X T . Chapman Mitchell, 

 of Philadelphia, the judge decided that it was an anticipation 

 of tin patent iii suit. Of course, this is the court of first in- 

 tan e and an appeal will probably be taken. 



mm PERMEABILITY 01 Rl BBER 'I'M CARBONIC ACID. 



In the "Chemiker Zeitung," 1914, page 1240, \", Rodt discusses 

 the diffusion of carbonic acid through rubber. He finds that 

 a pure vulcanized rubber tube filled with the gas will collapse 

 if kept in the air for from 12 to 24 hours and this collapsing is 

 greatly hastened if the tube is immersed in water. 



But if the gas inside and the air outside are perfectly dry there 

 collapse in one month's time. Carbonic acid is not absorbed 

 by rubber With water and carbonic acid in contact with rubber 

 only 6.3 per cent, was absorbed in 25 days, and the water 

 amounted to 6.12 per cent, so that only eighteen hundredths of 

 one per cent, of carbonic acid was absorbed. The rapid diffusion 



