May 1, 1919.] 



THE INDIA RUBBER WORLD 



423 



not cured to its maximum tensile strength showed an mcrease 

 in tensile strength in aging, but the increase was smaller than 

 in continued vulcanization. After-vulcanization, as in ordinary 

 vulcanization, brought the curves at last into the brittle state. 



3. The coefficient of vulcanization by aging at temperatures 

 below 80 degrees C, equivalent to 176 degrees F., increased 

 only little. A curve obtained by aging showed a much lower 

 coefficient than when obtained by ordinary vulcanization. 



4. By prolonged aging these changes continued in the same 

 manner without stop, though in diminishing degree. A definite 

 final stage can in no case be reached before the rubber becomes 

 brittle. 



CHEMICAL PATENTS. 



THE UNITED STATES. 



COMPOUNDING Rubber with Powdery Substances. — An im- 

 palpable powder, such as lampblack, is mixed with a 

 concreting and binding liquid such as starch paste, producing a 

 granular condition ; the water is evaporated and the dry granu- 

 lar lampblack incorporated with rubber. (Wilbur Clark Knowl- 

 ton, and Harry A. Hoffman, Akron, Ohio, assignors to The 

 B. F. Goodrich Co., New York City. United States patent No. 

 1,286,024.) 



Coating Material for Handles of Sporting and Trade 

 Implements and Method of Applying. — A coating comprising 

 material including gutta percha and balata soluble in a suitable 

 solvent and when applied readily drv'ing out and leaving the 

 material in the form of an adherent, elastic, non-absorptive 

 surface free from stickiness under ordinary temperatures and 

 use. (William S. Sellars, Brooklyn, and Wyatt W. Taylor, 

 Spuyten Duyvil — both in New York. United States patent No. 

 1,293,949.) 



.•\dhesive Rubber Composition. — A process for producing an 

 adhesive material which comprises mixing thickened castor oil, 

 dissolved in a volatile solvent, with rubber-containing latex, and 

 coagulating the mass. (Edward Mark Slocum, Medan, Province 

 of Deli, Sumatra, Dutch East Indies, assignor to General Rubber 

 Co., New York Citj-. United States patent No. 1,293.957.) 



Producing Substances Resembling Caoutchouc. — The pro- 

 cess of producing substances resembling caoutchouc but insolu- 

 ble in benzene, by polymerizing a hydrocarbon of the butadiene 

 series in the presence of about three per cent of an oxidized but 

 undecomposed terpene containing at least ten carbon atoms in 

 the molecule, otherwise described as an organic substance con- 

 sisting of an ozonide containing oxygen in a loosely combined 

 state and active chemically, said organic substance being soluble 

 in the hydrocarbon and capable of mixing with and reaching 

 every part of it. (Henry S. A. Holt and Gerhard Stemmig, 

 assignors to Badische Anilin & Soda Fabrik — all of Ludwi 

 Germany. United States patent No. 1,294,662.) 



shafen, 



Regenerating India Rubber. — Vulcanized rubber is regener- 

 ated by grinding, dissolving under mechanical action in the 

 smallest possible quantity of oil, such as linseed or castor oil, 

 which is vulcanized into factice, and exposed to a temperature 

 of 150 degrees C. The solution is subsequently heated with as 

 much sulphur, at such a temperature, and for such a period, as 

 will convert the oil into factice. The product may, witli or 

 without the addition of new rubber, be vulcanized or otherwise 

 treated as new rubber is treated. (S. van Raap, 102 Wees- 

 perzijde. .Vmslerdam, Holland. British patent No. 122,188.) 



THE UNITED KINGDOM. 



India Rubber Compositions. — \ mixture of pure rubber, flour 

 from waste vulcanized rubber, and sulphur with which may be 

 mixed other material such as Pontianak, a clear sticky gum, 

 castor oil, ground fiber, white lead and dissolved resin. The 

 composition is intended for use in making artificial leather, floor 

 cloth or tires, vulcanized by hot or cold process. (W. Stocks, 

 334 George street, Fitzroy, Victoria, Australia. British patent 

 No. 121,136.) 



Waterproof Compositions. — A composition for waterproofing 

 boots, shoes, and other leather articles, consisting of grease, gum, 

 wax, oil, and rubber in the proportion of 25, 5, 30, 35 and 5 per 

 cent, respectively. The grease, gum, and wax are first mixed 

 together under heat, the oil is then added and finally the rubber. 

 (H. C. Trenaman, 56 Catherine Street North, Hamilton, Ontario, 

 Canada. British patent No. 121,587.) 



I 



Po 



LABORATORY APPARATUS. 



IMPROVED SPIRAL BALANCE. 



THE well-known Jolly's spiral spring balance, useful in the 

 rubber laboratory for determining the specific gravity of 

 compounded rubber, has been improved to facilitate the reading 

 of the instrument. The improvement 

 consists of a small mirror attached to 

 the sliding index, bearing a horizontal 

 line etched upon it, and a device for 

 limiting the motion of the spring. The 

 indicator attached to the end of the 

 spring is a small metal disk which may 

 be set very accurately in line with its 

 own image and the etched line on the 

 glass. 



REGISTERING DOUBLE CALIPER. 

 The registering double caliper shown 

 in the cut will be found a decidedly 

 convenient tool for the testing labora- 

 tory for measuring the diameter of 

 hose under test for expansion. Hose 

 makers and inspect- 

 ors will also find this 

 caliper a handy tool/i 

 in their departments, 

 as it is adapted for 

 measuring both ex- 

 ternal and internal 

 diameters. The di- 

 mensions may be read 

 to sixteenths of an 

 ..iSifRSN ""^'^ °" ^^^ graduated I 



jillfir A 'iik. « a'"'^- Central Scientific 

 ^mJ^ V3^ Co., 460 East Ohio 

 _^ " street, Chicago, IIH- 



P.alance. 



FGIsTl KIM 

 L \LIItR 



RUBPRON MINERAL RUBBER. 



is a recently perfected hydrocarbon product designed 



Rubp: 



for use as a preservative and filler in rubber compounding. It 

 is a combination product based on pure asphaltum. It possesse.s 

 great ductility and freedom from hardening or oxidizing effect. 

 Its melting point is 315 degrees F., specific gravity 1.058, and it 

 contains two per cent of sulphur. 



LIQUID CAUSTIC SODA. 



Liquid caustic soda in water solution of different strengths is 

 available to the rubber reclaiming trade. It is shipped in tank 

 cars and used according to strength. The object is to effect a 

 saving in manufacturing cost by avoiding complete evaporation 

 and the use of the drums in which the solid caustic is packed. 

 The liquid caustic is extensively used where the freight rate is 

 not high enou.gh to offset this saving. 



Replete with inform.'\tion for rubber manufacturers — H. C. 

 Pearson's "Crude Rubber and Compounding Ingredients." 



