THE INDIA RUBBER WORLD 



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Possibilities of the Peachev Process. 



IN CONSIDEKIKG an invention that appears to be revolutionary 

 it is interesting and always well to know the source. The 

 inventor of the Peachey process, S. J. Peachey, is a well- 

 known English chemist, who since 1902 has been lecturer in 

 chemistry in the Manchester College of Technology and lec- 

 turer also in the faculty of technology of the University. 

 For many years he has devoted much attention to rubber, 

 has produced a number of valuable compounds and has done 

 much toward the development of accelerators. 



BRIEF OF THE PROCESS AND GASES. 



The process, briefly, is the exposure of rubber compounded 

 or pure in sheet form without sulphur, exposed first to sul- 

 phur dioxide gas, followed by exposure to hydrogen sulphide 

 gas, all without heat; or saturation of rubber solution with 

 the same gases. Sulphur dioxide, one of several oxides of 

 sulphur, is a colorless gas resulting from the burning of sul- 

 phur. It was first obtained in the pure state and recognized 

 by Priestley in 1775. It occurs in nature in the gas issuing 

 from volcanoes and in solution in waters of some springs. 

 Enormous quantities of sulphur dioxide are used in the man- 

 ufacture of sulphuric acid by the combustion of sulphur or a 

 metallic sulphide. 



Sulphur dioxide is colorless and has the peculiar irritating 

 odor observed when sulphur is burned. It is 2.2 times heavier 

 than air and under standard conditions one volume of water 

 dissolves about 80 volumes of the gas. It is easily liquefied. 

 a freezing mixture of ice and salt being sufficient to effect 

 condensation under atmospheric pressure. The resulting 

 liquid is colorless and is a commercial product, being stored 

 in strong glass syphon bottles or metal containers. 



Hydrogen sulphide is a colorless gas of very oflfensive 

 odor, familiar as the odor of rotten eggs. It is 1.18 times as 

 heavy as air and may be readily condensed to a colorless 

 liquid. One volume of water at ordinary temperature dis- 

 solves three volumes of the gas, which may be expelled 

 completely by boiling. In pure form the gas acts as a violent 

 poison and even when diluted largely with air produces 

 headache, dizziness and nausea. Fortunately its extremely 

 disagreeable odor gives warning of its presence. It is not an 

 article of commerce but may readily be prepared by the 

 action of hydrochloric acid on iron sulphide and may be 

 stored in glass or metal containers. 



PRECURSOR OF VULCANIZATION IMPROVEMENT. 



No doubt the Peachey process is of value, of great value, 

 but it is probably not the last word in this line of vulcaniza- 

 tion. Just as aniline came into use as an accelerator and 

 was later dispossessed by other better catalyzers, so will 

 the dual gases be superseded by compounds, liquid, solid 

 and gaseous, that will produce vulcanization within the rub- 

 ber compound and be so graded and governed that e.xact time 

 limits and varying results be accurately obtained. This is 

 assured by the general interest in this line of work and the 

 searching experiments that have long been carried on in 

 many of the great rubber laboratories. 



That curing by quick and high heats is often a detriment is 

 freely conceded. Fabrics are certainly not improved; indeed 

 certain of them are weakened. Animal substances like 

 leather are burned unless specially prepared to withstand 

 the heat and even then suffer a loss of original strength. 

 Where the Peachey process is adaptable, therefore, fabrics 

 and strengtheners of all sorts may be expected to preserve 

 their original integrity. 



The possibility of getting rid of chloride of sulphur and 

 bisulphide of carbon will appeal to those who use the cold 



cure. To be sure, ihroiiyh modern safeguards the ill effects 

 of both the solvent and curative agent are guarded against, 

 but neither are pleasant ingredients either in store or in use. 

 Of the claims to superiority in result some attract instant 

 attention and some do not. The claim that porosity will be 

 much lessened is doubtless sound, but with a very definite 

 knowledge of the cause of porosity, both chemical and me- 

 chanical, the evil is rarely present. Anti-porous ingredients 

 and the pressure cure make gas bubbles almost an impos- 

 sibility even in the greenest of stocks. 



ON THE RELATIVE IMPORTANCE OF COLORS. 



The importance of color or .-hades of color in soft rubber 

 goods is generally overestimated. In ninety-eight per cent 

 of the manufactured product it is of absolutely no importance. 

 .A very little reflection will make it evident that pink belting, 

 robin's-egg blue wire covering, old-rose valves, or Titian 

 truck tires would be of no interest to users. Not only is 

 this true in mechanical lines, but in footwear and clothing 

 as well, where the bulk of the product will always be black 

 by preference. Furthermore, in all of the important lines 

 where reds, tans, blues or whites are demanded they are suc- 

 cessfully produced at reasonable cost. In druggists' sun- 

 dries and notions, as bathing caps, color, however, is of 

 value. Ten years ago the announcement that any desired 

 shade could be obtained in rubber would have interested 

 manufacturers exceedingly. Today, however, so great a 

 variety of colored compounds is produced that the actual 

 necessity does not exist. This does not mean that other 

 shades would not be used if available, but the void of past 

 years no longer exists. 



However, in light rubber surfaced clothing, particularly 

 for ladies' wear, there seems to be a considerable field. In 

 the past some beautiful effects in color have been obtained, 

 but with difficulty. Peachey's process, however, would seem 

 to open the door to the production of a great variety of 

 colors, shades and effects rivaling the finest fabrics, and such 

 as would appeal irresistibly to the decorative sex. 



In toy balls also, solid colors in cheap compounds would 

 obviate the necessity of painting the surfaces. It is quite 

 probable further that balloon fabrics colored to resist the 

 effect of sunlight might be more effective than under exist- 

 ing methods. 



In the cases of dipped goods and spreader goods when 

 cured by acid or vapor, manufacturers may and doubtless 

 will find in the new process a surer way of securing a greater 

 variety of colors than at present and it is in those lines that 

 a considerable development is probable. 



.\n advantage would seem to lie in the complete vulcaniza- 

 tion that the process insures, something that neither the hot 

 process nor the sulphur chloride cure accomplishes. Another 

 is the freedom from efflorescence of sulphur (bloom) on the 

 surface of finished goods. 



CURING METHODS CONJECTURED. 



Just how one would cure rubber goods by the Peachey 

 process is a very interesting subject upon which to speculate. 

 In spreader work, for example, the gas impregnated com- 

 pound would be applied as usual. The first coat as soon as 

 the solvent was evaporated would, unless we err, at once 

 cure itself. The second coat would therefore be spread upon 

 a coating already vulcanized. Not that this would matter 

 probably, but it is a bit startling. Or the goods could be 

 spread with the ordinary compound minus the sulphur and 

 exposed to the action of the gases in an ordinary dry heater, 



