October 1, 1919.] 



THE INDIA RUBBER WORLD 



21 



tion to the reaclion combining sulphur with rubber. Nitrogenous 

 compounds are the most active catalysts. 



The paper of G. D. Kratz, A. H. Flower and Cole Coolidge 

 on "The .\ction of Certain Organic Accelerators in the Vulcan- 

 ization of Rubber" treated on substances all of which have been 

 discarded in their practice for various reasons. The accelerating 

 effect was determined in percentage proportion for each catalyst 

 treated referred to that of aniline as standard, .\nhydrous 

 formaniline was rited at 75 and of para-phenyline-diamine at 

 17. .Accelerators should be used in proportions based on their 

 molecular weights. 



C. W. Bedford and Winfield Scott on "Reactions of .Acceler- 

 ators During Vulcanization" illustrated these reactions by 

 graphical formulae. The opinion was expressed that thiocar- 

 banilide is the most widely used accelerator in American prac- 

 tice today. The presence of zinc oxide has a very marked in- 

 fluence in aiding the action of thiocarbanilide. The effect of this 

 accelerator is not due to its splitting off aniline. 



D. F. Cranor spoke on "The Effect of Organic .Accelerators 

 on the Vulcanization Coefficient" with special reference to 

 he.xamethyl-tetramine and thiocarbanilide, using mixings of 

 smoked sheets 100; sulphur 6; zinc oxide 1. and one-half of 

 one per cent of hexamethyl-tetramine and thiocarbanilide. Brown 

 crepe will not cure satisfactorily without the use of accelerators. 

 The presence of zinc oxide is found desirable to activate the 

 accelerators. 



The discussion on the above papers on accelerators was very 

 brief. Dr. L. E. Weber asked if the action of the catalyzer on 

 the vulcanization of rubber with sulphur is considered as apart 

 from the polymerizing effect taking place in the rubber. To 

 this, J. H. Scott replied that a catalyst may take part in both 

 vulcanization and polymerization, but does not necessarily pol- 

 ymerize the rubber. 



G. D. Kratz in answer to a question explained that his views 

 were in substantial agreement with those of Ostromislensky on 

 vulcanization. 



The essentials of a procedure for the determination of cellu- 

 lose in rubber goods was considered by S. W. Epstein and R. L. 

 Moore and details of a proposed method given. This method 

 is conducted in three stages: (1) digestion for four hours in 

 cresol, (2) treatment with hot ten per cent solution of hydro- 

 chloride acid, (3) acetylation of the cellulose. The loss of 

 weight due to acetylation represents cellulose. 



Reviewing and summarizing the investigations of Eaton, 

 Grantham and Day: H. P. Stevens; and Philip Schidrowitz. 

 Dr. J. B. Tuttle in his paper on "The Variability of Crude 

 Rubber," stated that this variability is measured by the differ- 

 ences in effect of the accelerating substances natural to the 

 latex or formed in the crude rubber during preparation and 

 the retarding agencies introduced, as for example by smoking. 

 Such variations in curing quality are overcome in practice by 

 the use of two to four per cent of litharge or one-half to one 

 per cent of ordinary organic accelerators, such as aniline or 

 hexamethyline-tetramine. The work of Eaton shows the vari- 

 ation the natural accelerators present and not the variation of 

 the rubber itself. 



Dr. Tuttle expressed the view that tensile strength compared 

 to rate of cure determines the value of a rubber in practical 

 use. For example, a slow-curing rubber with low tensile strength 

 can be rendered satisfactory for use by the addition of an ac- 

 celerator which will increase its speed of vulcanization and raise 

 its tensile to that of a rubber naturally possessing these qualities. 



D. C. Cranor advocated the use of the load required to pro 

 duce a standard elongation as the determining factor in prac- 

 tical cvahiation of crude rubber under manufacturing conditions. 

 Mr. Postmontier suggested that the executive committee of the 

 Rubber Division take under consideration and later report 

 practical methods of testing the variability of crude rubber 



under conditions prevalent in the manufacture of rubber 

 goods. 



H. P. Gurney, in considering "Some Methods of Testing the 

 Hardness of Vulcanized Rubber," compared the durometer of 

 Shore : the plastometer of Puscy and Jones ; the resiliometer 

 of Widney, and the densimeter of the Boston Belting Co. Hard- 

 ness of rubber was defined as the force required to displace a 

 unit volume of rubber and may be expressed bv the formula : 

 M 



UT' 



H, indicates hardness ; M, mass ; L. the load applied, and T, 

 duration of time of load application. 



"The Manufacture and Use of Crimson .Antimony" was briefly 

 treated by J. M. Bierer, who reported that the most practical 

 method found after extended study was by the formation of 

 antimony chloride by direct action of chlorine on the metal and 

 subsequent conversion of the product into antimony tri-sulphide. 



"Carbon Black— Its Properties and Uses," by G. St. J. Perrott, 

 read before the Division of Industrial Chemists and Chemical 

 Engineers, was by request of Dr. Tuttle read again before the 

 Rubber Division. General description of the manufacturing 

 process and machinery employed was given and illustrated by 

 lantern slides. Carbon black has many industrial uses, the 

 chief of which is the manufacture of printing inks and rubber 

 goods, 10,000,000 pounds annually being used in printing ink and 

 20.000,000 pounds annually in rubber goods, chiefly in tires. The 

 form of apparatus used in the condensation of the black from 

 the burning gas produces either "short" or "long" black, so 

 called because of the short buttery consistency of the prepara- 

 tion of oil and black in printer's ink or the opposite tendency 

 of the mixture to draw out when separated between the thumb 

 and finger. By microscopic examination the difference is seen 

 to he due to a tendency in the case of "long" black for the 

 particles of the pigment to agglomerate. The diameter of car- 

 bon black particles varies from 75 to 100 millimicrons. 



.A short descriptive paper, "Research on Zinc Products for 

 the Rubber Industry," was presented by P. R. CroU and I. R. 

 Ruby. 



Owing to the length of the program of papers and for other 

 reasons the following were omitted or read by title : C. Olin 

 North, "The Effect of Compounding Ingredients on the Physi- 

 cal Properties of Rubber." (Omitted.) "Symposium on the 

 Testing of Pigments." (Omitted.) C, P. Fox, "Laboratory 

 .Aprons." (Omitted.) H. E. Simmons, "The Value of a Li- 

 brary to the Rubber Laboratory." (By title.) 



.All papers read at the meeting are subject to the rules of the 

 .American Chemical Society and will not be published until 

 released by that body. 



The report of the Fruit-Jar Committee was filed. The efforts 

 of manufacturers and leading jobbers to educate jar-ring users 

 was endorsed and dependence on their guaranties advised. The 

 committee endorsed the recommendations of the ITnitcd States 

 Bureau of .Agriculture, States Relation Section, on jar rings, 

 with tests, adapted for use at the counter and in the kitchen for 

 determining jar-ring quality. Another test was added, namely, 

 pinching the flange of the ring folded each way. The rubber 

 should not show cracking under this treatment. 



The sessions of the Rubber Division closed with the election 

 of the following oflncers for the ensuing year. 



Ch.mrm.vn: Dr. \V. K. Lewis, Massachusetts Institute of 

 Technology. 



Vice-Ch.\trman: George D. Kratz, Falls Rubber Co. 



Secretary : Arnold H. Smith, The Goodyear Tire & Rubber Co. 



Executive Committee: J. M. Bierer, Boston Woven Hose & 

 Rubber Co.: W. W. Evans, The B. F. Goodrich Co.; C. W. 

 Sanderson, The Fisk Rubber Co. ; J. W. Scott, Plexus Tire & 

 Rubber Co.; George Oenslager, The B. F. Goodrich Co. 



