June 1, 1917.] 



THE INDIA RUBBER WORLD 



519 



the lactic fermentation in competition with other organisms; 

 hence the addition of sugar is necessary. For large quantities, 

 Gorter and Swart recommend 400-450 grams of sugar in SO 

 liters of water for each 175 liters of latex. The disadvantages 

 of the process due to discoloration of the rubber, and the fact 

 that only crepe can be prepared, are discussed. It is pointed 

 out that sugar is cheaper than acetic acid. 



B. J. Eaton ["Agricultural Bulletin Federated Malay States," 

 Vol. 5, 52 (1916), through "Chemical .\bstracts"] has demon- 

 strated that rubber prepared by coagulation in the presence of 

 sugar is in every respect equal to acetic acid coagulated samples, 

 and has a tendency to vulcanize faster. Crepe of e.xcellent color 

 can be prepared by coagulation in the presence of sugar in a 

 closed vessel, and subsequently soaking the coagulum for 24 

 hours in a five per cent solution of bisulphite of soda, as is done 

 in the case of "lump" rubber or cup coagulation. The e.Kclusion 

 of the air during coagulation prevents any preHminary darken- 

 ing due to oxidation. 



COAGULATING AGENTS FOR SHEET RUBBER, 



Coagulating agents for sheet rubber are discussed by Gorter 

 and Swart in Bulletin No. 6, West Java Rubber Testing Station 

 (through "Chemical .Abstracts" ). The work relates to the use 

 of various acids and salts for coagulating and the possibility of 

 their ultimate effect on the rubber. Hydrofluoric acid, sulphuric 

 acid and alum are not recommended, especially in the manu- 

 facture of sheet, where a portion of the acid or salt is retained 

 in the rubber. Experiments with the milk of young coconuts 

 show a content of five per cent sugar and an acid content of 

 only 0.4 per cent after seven days and of 0.46 per cent after 15 

 days. About half of the acid content was lactic acid, which 

 probably inhibited the development of the acetic acid fermen- 

 tation, and explains the low acetic acid content. 



should be nii.xed before filtration with alcohol or acetone. The 

 method is sufficiently accurate for technical purposes. 



METHODS OF ANALYSIS. 



DETERMINATION OF MINERAL MATTER IN VULCANIZED RUBBER. 



J P. PERHGRIX in "-Xnnales de Chimie -\nalytique" (Febru- 

 • ary 15, 1917), refers to the inaccurate results obtained b}' 

 direct incineration of rubber, due to losses of zinc, antimony and 

 lead in the process, stating his method as follows : 



One or two grams of finely rasped vulcanized rubber is heated 

 with 50 to 100 grams of anisol for six hours at 100 degrees C. 

 with frequent agitation until the rubber ceases to swell. Pure 

 benzene is then added in large excess and after standing several 

 days the mineral matters in the mixture are separated by cen- 

 trifugal force. 



The author prefers anisol to salol because the latter is too 

 expensive. Cresol is not favored because it affords unsatisfac- 

 tory results. 



CELLULOSE IN ETTBBER. 



A method for the determination of cellulose in rubber by 

 G. H. Hillen ["Gummi Zeitung," 670-1 (1916)] is given as fol- 

 lows, through "Chemical .\bstracts" (May 10, 1917) : 



Regenerated rubber and rubber freed of fabric by the me- 

 chanical process may contain cellulosic residues. For their deter- 

 mination Hillen recommends treating 0.2 grams of the finely di- 

 vided material with 30 cc. of Schweitzer's reagent, allowing the 

 mixture to stand six to ten hours without stirring ; filter through 

 a gooch and wash with ammoniacal water until the wash water 

 shows no color; acidify the united cellulose solution and wash 

 waters with dilute sulphuric, filter the precipitated cellulose on 

 a gooch, dry and weigh. The following points are of special im- 

 portance: (1) The sample must be carefully selected and pre- 

 pared by rasping with a file or similar means ; (2) the Schweitzer 

 reagent must be carefully prepared ; (3) the beaker containing 

 the sample and reagent must be well covered to avoid loss of 

 ammonia; (4) the precipitated cellulose must not be left long 

 in contact with the dilute acid, lest inversion occur; (5) since the 

 voluminous cellulose easily clogs the filter, the moist precipitate 



CHEMICAL PATENTS. 



the united states, 



Process of Tke.\tinc Automobile Tires and Inner Tubes. 

 Thickened neats' foot oil is applied to the inner wall of the tire 

 shoe for impregnation of the shoe and surface coating the inner 

 tube. [Frank S. Walton. Philadelphia, Pennsylvania. United 

 States patent No. 1,223,302.] 



Rubber Substitute. A composition of matter for use in the 

 manufacture of vehicle tires and like purposes, including Para 

 rubber, 8 parts; Kieselguhr, 2 parts; fuller's earth, 2 parts; as- 

 bestos, 3 parts ; oxide of lead, 5 parts ; sulphur, 1 part ; aluminum 

 wool. 2 parts ; cotton, 2 parts, and wood pulp, 4 parts. [Francis 

 A. Halsey, Philadelphia, Pennsylvania^ assignor of one-fourth to 

 Charles Hamilton, Philadelphia, Pennsylvania. United States 

 patent No. 1,223,692.] 



THE UNITED KINGDOM. 



P.VCKTNG. A composition of about equal parts of rubber and 

 mineral oxides, siKh as zinc oxide or silica, is used as a pack- 

 ing for steam, air or hot water. [E. T. Williams, 11 The Drive, 

 Golder's Green, London. British patent No. 103,776 (1917).] 



Recl.\imed Rubber. A plastic mass made by heating such 

 salts as aluminum, calcium or magnesium stearate, or iron, cal- 

 cium or magnesium palmitate with an oxidizing oil. In an ex- 

 ample, 1 part of aluminum stearate, dissolved in the same or a 

 smaller quantity of ozokerite or the like,: is' mixed witlj"4 to 10 

 parts of oxidized linseed oil at 20O to, :2S0 degrees €,^ The 

 product rnay be vulcanized, with addrfion of rubber, asphalt, 

 magnesia. Kieselguhr, chalk, red lead; etc. [E. S. Ali-Cohen, 

 43 Stadhoudersplein, The Hague. British patent No. 103,824 

 (1917).] 



THE FRENCH REPUBLIC. 



Co.^GULATioN. Process and apparatus to determine the volume 

 of acid needed to coagulate a given volume of rubber late.x. [T. 

 Cockerill. French patent No. 482.020.] 



LABORATORY APPARATUS. 



RUBBER EXTRACTOR. 



A PIECE of apparatus known as the New York Testing Labo- 

 ^*- ratory Extractor, wliile originally designed for the extrac- 

 tion of asphaltic materials, is a valuable acquisition to the rubber 

 laboratory, particularly for the chemist whose work requires the 



The Various Parts and the Assembled Extractor. 



extraction of large samples of rubber with volatile and inflam- 

 mable organic solvents. It can be used with any solvent com- 

 monly used in rubber analysis. The extractor combines safety, 

 capacity, efficiency, durability and economy of solvent. It is made 

 entirely of metal and is electrically heated, and was designed by 

 Charles P. Fox. [Howard & Morse, 1197 DeKalb avenue, Brook- 

 lyn. \ew York,] 



