

THE INDIA RUBBER WORLD 



[September I. 1915. 



the i Exhaustive experiments made by the note<l 



French scientist, Victor Henri, demonstrated tlini chrome yellow 

 (neutral chxom; inilin yellow absorb ultra- 



violet rays and nullifj thi ts. In France the first is most 



popular, wl Germany the second is most empl yed. fightlj 



"Parseval" (German Non-Rigid). 



woven fabrics help to prevent the penetrating effect of light, but 

 the yellow color is essential to save halloon fabrics from the 

 ultra-violet rays and their destructive effi 



As sulphur combines easily with the chromate, it is difficult 

 to vulcanize fabrics that are colored with lead chromate. the 

 combination of lead and sulphur producing lead sulphide, which 

 i< hlack. This inconvenience is overcome by simply coating the 

 ed layer of fabric with pure Para uncured and vulcanizing 

 the rubber coating of the second layer of fabric which is placed 

 underneath the colored one in making up the doubled fabric. 

 It is also possible to vulcanize chromed-colored fabric by heat 

 without seriously affecting its color, but great care must be 

 ised. Aniline yellow is also verj sensitive to \ ulcanization, 

 but it also can be easily handled. Unless treated with consider- 

 are aniline yellow-dyed fabrics turn to a greenish yellow 

 which affords no practical protection against ultra-violet rays. 

 Chrome-yellow fabrics will stand bright sunlight for months 

 without alteration, but it is very difficult to obtain a uniform 

 color with chrome yellow. 



METALLIZED FABRICS. 



A great step forward was made when "metallized" balloon 

 fabrics were introduced ["he outer surface of these is covered 

 with a thin coat of metal, which is Mown on to the fabric in a 



Mu \.\o" ( It vi.i v\ Semi-Rigid 



powder form as the latter comes out of the spreader which has 

 with a rubber solution. The powdered m< 



then rolled and smoothed in a calender. 



sclusivcly on account of its light 



ting the oxygen and the 



humidity of the air. Aluminum is not affected by sulphur or 

 anj of thi o ei illers usually employed in the manufacture of 

 rubberized fabrics. Water runs off metallized balloon fabric*, 

 which also throw off Sunlight, destroying the action of both 

 hi at .md of ultra-violet raj s. 



CHOII I ' 'I R1 BBER. 



Only the best of crude rubber can be used for balloon 

 fabrics and extra fine Para hard cure is best of all. For 

 this use the difference there is between fine Para soft cure 

 and hue Para hard cure is of very great importance. The 

 hard rurc is obtained by more intense smoking and is 

 easily recognized by the fact that its different layers are 

 Ij detachable from one another. Soft cure Para comes in 

 halls, the several layers of which it is very difficult to separate. 

 Para entrefine, Sernamby, negfoheads, as well as African rub- 

 ber, are not suitable for halloon fabrics. Well smoked planta- 

 tion sheet rubber and I eruvian ball rubber can be used in part, 

 but the) must not exceed 40 per cent, of the total, and great 



in must be exercised in \ulcanizing. for plantation as well as 

 Peruvian rubber requires a greater addition of sulphur. A 

 mixture of soft cure Para or weak Para, both irregular gums, 

 or a mixture of resinous rubber would create difficulties in 



Zeppelins in Their Shed (Rigid ). 



vulcanizing and the gumming would turn to resin in a very 

 short time. 



VARIOUS MIXINGS. 

 The washing and drying of rubber for the manufacture i I 



ball i fabrics does not present any peculiarities not known 



to rubber manufacturers. The same remark applies to the mix- 

 ing. Mr. Churret, a French chemist, recommends the following 

 compounds which have given g 1 practical results: 



MIXTURE A, for making f; tight: Kilos. Pi 



Fine Pari hard cure 4.000 8.8184 



Paraffin (point of fusion 132.8 Fahrenheit) 0.030 0.0661 



Sulphur (twice sifted) 0.400 0.8818 



• in. t. ,1 magnesia i twice sifted) 0.110 



MIXTURE B, to increase the tensile strength of the fabric: 



Fine Para hard cure 4.000 



si .: i ni 1 Fahrenheit) 0.040 0.0S8I 



Carbonate of magnesia I Mba magnesia) 2.600 5.7319 



Calcinated magnesia (twice sifted) 0.360 0.7936 



Fine sulphur 0.400 0.8818 



MIXTURE C, to I proof fabrics by cold vulcanization: 



Fine Para bard cure 4.000 



Paraffin (point of fusion 132. S Fahrenheit) 0.500 0.1102 



\- thesi compounds must be dissolved after mixing, the fol- 

 lowing rules laid down by Mr. Churret should he followed: 



"For mixing and massing, a mixer with cylinders about 1 

 meter (39.37 inches) will be used. The mixtures should never 

 contain more than S kilograms (17.64 pounds) of rubber, and 

 each of the ingredients should be weighed in clean containers. 



"For mixture A the Para should be worked \ l / 2 hours in the 

 mixing machine, then the rubber is wound around a mandrel 



