

THE INDIA RUBBER WORLD 



I'HIKl'ARY 1, 1915. 



What the Rubber Chemists Are Doing. 



BULLETIN No. 96 of the United States Hygienic Laboratory 

 contains accounts of a number of analyses of rubber goods 

 made to determine whether there were any substances 

 present of a nature injurious to persons coming in contact with 

 them. Nursing nipples were particularly examined. The report 

 says: "Bearing in mind the conditions of the infant's mouth, 

 it is undesirable that antimony be present. Lead, arsenic and 

 mercury should be absent. Magnesium zinc and clay are less 

 undesirable, and barytes are probably harmless.'' Antimony and 

 Venetian red were noted, in addition to zinc oxide. No lead, 

 arsenic £>r mercury were found. Generally speaking, the samples 



were found I" be quite harmless. 



ii rERMINING THE CHEMICAL COMPOSITION OF ( VOl rCHOUC. 



C. Harries, of the University of Kiel, and Otto Lichtenberg, 

 working quite independently, have been studying this question 

 by producing halides with hydrochloric acid and regenerating 

 the rubber by use. of pyridine, then forming the ozonides. Vari- 

 ous Other compounds have been produced. Harries concludes 

 from tbis and previous work (see "Berichte," Vol. 46, pages 733 

 and 2590; "Chemical Abstracts," 1914, page 260; "Journal of 

 the Society of Chemical Industry." 1913, page 983; "Annalen," 

 Vol. 406, 1914, page 173, and 1913, page 395; "Gummi-Zeitung," 

 November, 1913, page 168; "Journal of the Society of Chemical 

 Industry," 1913, pages 203 and 264; also "Chemical Abstracts" 

 of 1913, pages 346, 1502. 1986 and 2860; that the theory of the 

 8 carbon ring must be abandoned and that raw rubber is not 

 1.5 di-metbyl clyclo-octadiene, but that the molecule must be 

 much larger, with at least 20 carbon atoms. 



Lichtenstein seems to get about the same results ("Chemischer 

 Zeitung," 1914, page 124 i. The work of both these authors is ab- 

 stracted in "Chemical Abstracts," January 20, 1915, as is that of 

 Caspari on osmosis, referred to in The India Rubber World, 

 October, 1914, page 17. An abstract of an article on vulcanizing 

 rubber shoes, from the "Gummi Zeitung." will be found in the 

 same volume, and also a description of a friction testing machine 

 by J. M. Bieber. 



R. B. Rice has obtained Canadian patent No. 158.899 for vul- 

 canizing under pressure. Later we refer to other patents along 

 this line. 



In the "Journal of the American Chemical Society" for De- 

 cember. 1914. page 2468, there is a record of studies by G. N. 

 Lewis and M. Randal on "The Free Energy of the Various 

 Forms of Sulphur." The article begins with the statement that 

 "no other element is known to occur in so many forms as 

 sulphur." 



This seems to be largely made up of calculations based on the 

 experiments of others, who are quoted. It will he of interest to 

 those who are studying the functions of sulphur in vulcanization. 



The January issue of the "Journal of Industrial and Engi- 

 neering Chemistry" contains, on page 21, an article by Morris 

 Weiss, of the Barrett laboratories, on "The Determination of 

 itic Gravities of Tars, Oils and Pitches'' On page 34 is art 

 article describing a method of determining the unsaponifiable 

 matter in ether extracts. This was developed by the Texas 

 experimental station. 



SOME NEW PATENTS RELATING TO RUBBER. 

 David Spencc, of Akron, Ohio, who assigns to The B. F. 

 Goodrich Co., has received United States patent No. 1,122.653 

 for dyeing rubber. The claim is for "treating rubber with an 

 aromatic amin in aqueous solution, then subjecting to a dye- 

 forming bath." That is, the raw rubber is treated with aniline 

 oil till some of the oil has been absorbed ; then, by use of nitrites, 

 the aniline is fixed on the fibre, and ■vhen treated with beta- 

 naphthol-sodium salt, for example, will develop a blood-red 



color. Recently (The India Rubber W'uri.u, November, 1914. 

 page 67, and December, 1914, page 130) comprehensive patent- 

 for the Use of coal tar dyes have been granted Beyer & Co. 



Lewis Carter Warner, who assigns to the Beacon Falls Rubber 

 Shoe Co., of Beacon balls, Connecticut, has received United 

 State-, patent No, 1,122,824, which claims the vulcanization of 

 rubber shoes by subjecting them first to a vacuum, then to 

 pressure-, and afterwards vulcanizing. Quite recently (The 

 India Ri bbeh World, November, 1914, page 95) a patent was 

 issued which comprised a system of vulcanizing under vacuum. 



Herbert W. Kugler, of Akron, Ohio, who assigns to the Fire- 

 stone Tire & Rubber Co., has obtained United States patent No. 

 1,124,920 for a process of reclaiming rubber, which consists in 

 heating under pressure with alkali and aniline (The India 

 Rubber World, October, 1913, page 37, and August, 1914. 

 page 622). 



Leo Dart, who assigns to the Electro-Chemical Rubber & Man- 

 ufacturing Co., has dbtained United States patent No. 1,120,795 

 for rubber-coated articles and method of producing the same. 

 The essence of the invention seems to be in putting bismuth or 

 its alloys on the surface of the metal, which allows the rubber 

 to be vulcanized thereon. In United States patent No. 1,120,794 

 the same inventor makes the above claims for antimony. 



Otto Rohm, of Darmstadt, has obtained United States patent 

 No. 1,121,134 for process of making rubber substitute, which 

 consists in vulcanizing any acrylic acid ester. 



ANALYSIS OF RUBBER. 



In the November, 1914, issue of the "Chemical Engineer," the 

 methods used by the Armour Institute of Technology for the 

 analysis of rubber are detailed in full. 



The analysis of raw rubber is first taken up and the sampling 

 methods used are described. While it is recommended that large 

 samples be made by mixing a great number of small samples 

 taken from various parts of the whole lot, no definite process 

 of procedure is outlined. 



Moisture: The rubber is dried in a vacuum desiccator over 

 sulphuric acid, with weighings extending over several days, but 

 it is recommended that for technical work, drying in a stream 

 of gas be used, notwithstanding that gas is absorbed by the rub- 

 ber to some extent, ft is maintained that concordant results 

 are what is required rather than absolute exactness. 



Estimation of Resins: This is made by acetone extraction in 

 a modified Wiley-Soxhlet apparatus, first wrapping the samples 

 in cheese-cloth in which it is afterwards weighed after five 

 hours' drying at 90 degrees C. in hydrogen. The extract, after 

 driving off acetone, is saponified. The unsaponifiable matter is 

 extracted in a separatory funnel with ether. The ether extract 

 of unsaponifiable matter is dried and taken up in alcohol, and 

 the waxy hydrocarbons are frozen out with ice and salt. They 

 are dissolved in chloroform, dried and weighed. This is called 

 the resins. 



Determination of Insoluble Matter: A sample of one-half 

 gram to one gram is weighed and dissolved in a graduated 

 cylinder with benzol in about two days. The solution is made up 

 to 200 C. C, and after settling, an aliqudt part of solution is 

 taken off, evaporated to dryness and weighed. The difference 

 between this weight and the same proportion of the original 

 sample represents the same proportion of insoluble matter which 

 is thus calculated and determined. 



N*itr*ogen. This is determined by the ordinary Kjeldahl 

 method. 



Estimation of Ash: Gentle incineration in a muffle is used, 

 the residue being weighed. By examining the ash some con 

 elusions can be drawn as to the origin of the rubber. 



