290 



THE INDIA RUBBER WORLD 



[March 1, 1916. 



The values for />» for some of the liquids as used in experi- 

 ments were: carbon disulphide, 0.916; chloroform, 0.940; toluene, 

 0.870; ether, 0.718; benzol, 0.840; xylene, 0.849; light petroleum 

 spirit, 0.763; oil of turpentine. 0.848; benzyl chloride, 0.841 ; nitro- 

 benzene, 0.639. 



It follows from the formula that the velocity of absorption in 

 any one experiment is proportional to (/>« — />)". 



SOLVENTS or 6UTTA PERCHA. 



Herman Prinz has found that oil of eucalyptus and oil of caju- 

 put dissolve gutta percha due to the presence of cineole. Oil of 

 cloves and oil of cinnamon do not contain cineole and apparently 

 have no solvent effect on gutta-percha. 



CHEMICAL TREATMENT OF RUBBER. 



THE UNITED STATES. 



El.\stic Prodlxts. 1.159,257 and 1,159,258. Georges Nuth.— 

 The process consists of producing from a sulphurized oil 

 factice by the action of a compound (amin) capable of removing 

 loosely combined chlorine, a resulting body more resistant to 

 heat, water and acids than natural gums, and with a greater 

 elasticity than the corresponding chlorinated factice. 



IsopRENE. 1,159,380. A. Heineman. Vapors of turpentine oil 

 are passed over silver heated to about 450 degrees F., giving a 

 yield of isoprene equal to 25 per cent, of the turpentine oil used, 

 together with about an equal amount of other depolymerization 

 products. About 2000 cc. of vapor per hour may be passed 

 through a silver tube of 6 mm. diameter, 4 meters long, wound 

 into a close coil. 



Pigment. 1,169,253. Henry A. Gardner. Process for making 

 a pigment containing lead and barium carbonates, which consists 

 in forming a basic carbonate of lead and precipitating barium 

 carbonate in intimate association therewith. 



Rubber Substitute. 1,171,187. Alfred A. Glidden, assignor 

 to Hood Rubber Co. The process consists of heating vulcanized 

 rubber waste with any unsaturated hydrocarbons of the series to 

 which butadiene is the lowest member, and stearic acid in defi- 

 lite proportion, the operation taking place in sealed vessels at 

 212 to 248 degrees F. for periods of one to three weeks. 



THE ITNITED KINGDOM. 



W.vTERPROOF Compositions. 24.106 (1914). C. L. E. Melsom- 

 Brixton. A resilient waterproof composition is obtained by 

 steeping gelatin or glue or both in skimmed or separated milk, 

 then mixing with glycerin, applying heat to produce liquefaction. 

 and finally adding potassium bichromate, ground leather, and 

 other ingredients, such as dextrin, paraffin wax, Venice turpen- 

 tine, linseed oil varnish, glucose, and a preservative with or with- 

 out coloring matter, the mixture being heated and stirred. 



THE DOMINION OF CANADA. 



Proofing F.\bric with Rubber. 165,820. William Muntz. The 

 process consists of impregnating with two solutions, successively 

 introducing with the second solution substances capable of form- 

 ing harmless compounds in the fabric by neutralizing the sul- 

 phurous and sulphuric acid present. 



Elastic Material. 166,177. Maurizio Baricelli. A combina- 

 tion of a gelatinous substance, water, glycerine, antimony pent- 

 oxide, acetic acid. Before using there is also added formalin 

 and a substance of high thermal conductivity such as powder of 

 aluminum. 



OTHER CHEMICAL PATENTS. 



© 



PATENTS 



477,586 (February 10. 



of natural o 



477,789 (February 24, 



THE FRENCH REPUBLIC. 

 ISSUED (With Dates of .Xpplication). 

 1915). Process for accelerating the vulcanization 



artificial rubber or similar materials. S. J. Peachy. 

 1915). .\ mastic filler for oneumatic tires, and 

 anufacture. S. Ephrussi and S. Bernstein. 



LABORATORY APPARATUS. 



MELTING POINT OF PARAFFIN WAXES. 



A X apparatus and method for studying the melting point 

 '*^ of paraffin waxes, as proposed by F. H. Small, will be of 

 interest in rubber laboratories. 



Commercial paraffin is not a chemical individual but a 

 mixture of related com- 

 pounds. Its so-called 

 melting point is merely 

 the average of the melt- 

 ing points of the nu- 

 merous waxes making 

 up the composite 

 whole. Two samples 

 of paraffin wax, desig- 

 nated as of the same 

 melting point, may be 

 of radically different 

 composition. A 

 so-called crude may 

 consist of individual 

 waxes whose melting 

 points cover a wide 

 range of temperatures, 

 while a refined wax may consist to the extent of over 90 

 per cent of waxes whose melting points lie within a range of 

 5 degrees. Naturally these two waxes will not behave in 

 the same way. will not show the same plasticity and physical 

 qualities. It was to secure a more definite idea of the com- 

 position of commercial paraffin wax than was afforded by a 

 simple melting point determination that the apparatus here 

 described was constructed. 

 In the accompanying diagram — 



A is a glass tube, the smaller part being of uniform bore 

 and graduated in equal divisions; B is a glass plunger the 

 disk pf which fits easily the bore part of the enlarged part 

 of A. C is a brass disk bored to fit the stem of B and of 

 the same external diameter as the disk of B. 



In use B is inserted in the upper part of A. Enough 

 of the wax is shaved and introduced into A so that when 

 melted it will nearly fill the graduated tube of A. The brass 

 disk C is then slipped on B and allowed to press down the 

 shaved wax. The lower end of the graduated tube A is 

 closed with a cork reaching just to the zero mark and the 

 apparatus as prepared is inserted in a tall one-liter breaker 

 filled with water to above the level of the wax as shown 

 in D. 



The water is warmed by a burner below and is stirred 

 at frequent intervals. The warming process is continued 

 until such time as the wax shows signs of softening. The 

 temperature is then raised very gradually, the plunger B 

 being moved slightly up and down to facilitate the flow of 

 any melted wax into the graduated tube. When some of the 

 wax melts and runs down, the temperature at which this 

 occurs is recorded. The temperature is then raised a degree 

 at a time and held at each degree for seven minutes, the 

 plunger B being moved slightly up and down at intervals, 

 as before, to free the melted wax. At the end of each seven- 

 minute period the temperature and scale reading are re- 

 corded. The process is continued until the wax is all melted„ 

 From the scale readings a simple calculation shows the 

 percentage of the wax melted at any given temperature. The 

 temperature at which 50 per cent was melted corresponds 

 to the melting point as usually determined. If the melted 

 wax is allowed to harden in the tube its inspection will usually 

 show whether the wax contains an appreciable amount of oil. 

 The apparatus and method have been found sufficiently 

 accurate for commercial purposes. 



