238 



THE INDIA RUBBER WORLD 



Januakv 1, 1921 



pelled by the horizontal dn-ing apparatus, Fig. 9, which is essen- 

 tially a horizontal multiple-deck steam-pipe dryer, through which 

 the fabric is run and the solvent expelled. 



Final thorough dr>iiig and cooling require that the coated 

 fabric be passed also through a vertical dryer and lastly on an 

 overhead, open drying and cooling apparatus. Fig. 10. From the 

 latter apparatus the coated duck issues ready for the belting mak- 

 ing-up processes. 



IMPREGNATION BY SPREADING MACHINE 



The French system of impregnating duck with balata is by 

 the use of the ordinan,- spreader. As in the case of spreading 

 rubber composition, this method involves a preparation in solvents 

 of the pure or compounded gum to a fairly thick consistency 



Fig. 13. Soiling and Marking 



TTtoi 



Machine 



Fig. 14. Dry Masticating llaoMne 



^^- 



l,£r 



Pig. is. Belting Trlrmlng Machine 



Fig. IS, Belt Cutting and Measuring Machine 



Daz-id Bridge & Co.. I.imitcJ 



which admits of even distribution on tlie warm duck as the latter 

 passes through the plastic mass between the roller and spreading 

 knife. As in ordinary spreading of rubber stock, the solvent is 

 eliminated from the fabric by evaporation as the goods pass over 

 a drying table warmed by a steam heating system. 



IMPREGNATING BY FRICTION CALENDER 



During the Great War, owing to the scarcity of solvents, the 

 French makers of balata belting found it feasilile to use the 

 ordinary three-roll friction calender for applying balata to warm 

 duck, thus saving both time and solvent. 



BALATA BELT-MAKING MACHINERY 



By whatever method of impregnation the balata-coated duck 

 may be prepared, it is made up into belting in specially designed 

 machines here illustrated. 



The first operation is cutting the fabric to the widths necessary 

 to make the desired plies. This is rapidly 'and accurately done 

 by a special slitting machine, Fig. 11. The fabric is next folded 

 back upon itself and passes through the rolling machine. Fig. 12. 

 In these machines the balata stock is kept sufficiently warm to in- 

 sure the strongly adhesive condition of the balata compound 

 necessary to bind the plies into a homogeneous body under the 

 rolling pressure of the building machines. After having been 

 rolled two-ply thick the duck passes over a conveyor and is 

 again folded, heated and rolled, and so on until the desired num- 

 ber of plies is completed. 



The warm belt is then ready for stretching lietwccn the strain- 

 ing heads in connection with a stretching machine. The belt is 

 cooled while under strain so that the stiflF balata may fix the 



warp of the fabric at the stretched length which will not further 

 elongate under the service strains of power transmission. 



After stretching and cooling, the belt is ready to receive a final 

 wOvering of balata. This is applied to one side only as the belt 

 goes through the rolling and marking machine. Fig. 13. On the 

 opposite or driving contact side the surface is left as impreg- 

 nated. The composition used as a cover is generally inferior in 

 quality to that used in impregnating the duck and is prepared 

 without solvent in the dry masticating machine shown in Fig. 14. 



The belt is finally finished in the trimming machine, Fig. IS, 

 which trims and finishes the edges, stamps the surface with the 

 maker's trade mark, and delivers the goods in a finished roll 

 ready for measurement and cutting to specified lengths as re- 

 quired by orders for shipment. 



COMPOSITION AND TESTS" 

 TYPICAI. COMPOUNDS 

 Xo. 1. Exterior Coating: 

 Specific gravity. 0.989. 

 Ash, 2.5.1 (iron and magnesia). 



Adhesive coating: 

 Ash, 1.29 per cent. 



Weight of duck. 852 grams per squ.-ire meter. 

 Weight of gum, 425 grams per square meter. 

 Weight of exterior coating, 500 grams per square meter. 

 Adhesive temperature of the gum, 50 degrees C. 



No 2. ExTERi iR Coating: 

 Specific gravity. I.C56. 

 Ash, 12.09 ('ron an.i magnesia). 



Adhesive coating: 

 Ash, 1.38 per cent. 



Weieht of ducl\, 745 grams per square meter. 

 Weight of gum, 300 grams per square meter. 

 Weight of exterior coating 550 grams per square meter. 

 Adhesive temperature of the gum, 54 degrees C. 



ANALYSIS OF BALATA BELTING MIXTUHES 



Sam- Percentage Specific 



pie Composition Gravity 



Washed balata floating 



Deresinated balata 



1 Washed balata 50 



Organic fillers 50. 



8 Washed balata 66 1.186 



Mineral fillers A-34. 



13 Washed balata 50% 1.350 



Mineral fillers A-50. 



14 Washed balata 50 1.350 



Mineral fillers B-50. 



15 Washed balata 50 1.570 



Mineral fillers C-50. 



33 Washed halata 66 1060 



Mineral fillers B-34. 



114 Washed batata. 50 floating 



Reclaimed balata 50 



0.630 

 0.350 



0.650 

 0.650 



0.650 

 0.580 



35 



120 



210 



45.5 

 45.5 



46. 



41. 



40. 

 43. 



ADHESION TESTS OF PLIES 



"Friction" Test or 

 Resistance to Separation 



r- —^ ^ 



Adhesion Between Plies Between Plies 



Temperature One and Two Two and Three 



Samples Degrees C. Kilos. Kilos. 



Washed balata 56 4.986 4.686 



No. 1 50 1.936 1.286 



No. 2 54 2.236 2.336 



No. 14 58 2.032 1.934 



No. 33 47 3.259 3.114 • 



No. 114- 50 2.307 2.180 



^From article bv Gustave Bernstein in T.e Caoutchouc et la Gutta Percha, 

 March 15, 1920. 



NEW STYLES AND MATERIALS IN BRITISH WATERPROOFS 



From England comes a good-looking line of waterproof cloth- 

 ing made of rubberized cloth in various colors and materials. 

 This company makes a specialty of ladies' high-class garments 

 and capes of silk lined with pure rubber. Others are made of 

 rubberized cotton and cotton-and-wool mixtures. ' The styles 

 shown are nobby and becoming, and perfectly appropriate for 

 stormy weather. Motor jackets, motor suits, cycling capes and 

 children's capes with hoods are included in this line of rubber- 

 ized clothing.— The Crown Court Waterproof & Rainproof Co., 

 Limited. Crown Court, Ashley Lane, Manchester, England. 



