THE RUBBER INDUSTRY — GIBBONS 209 



mentioned as an important class of accelerators. It was fomid that 

 they can be prepared in such a way as to have nonaccelerating prop- 

 erties and yet give substantial improvement in resistance to aging. 



The original purpose of antioxidants was to prolong what might 

 be called the ordinary life of rubber goods — that is, to make them 

 less likely to soften or become brittle with time. Later, however, 

 it was found that they conferred other beneficial properties on cer- 

 tain types of rubber compounds. Kesistance to abrasion and to 

 cracking on repeated bending, known as flex cracking, were also 

 improved. 



We have discussed the aspects of that department of rubber tech- 

 nology commonly known as rubber compounding. The work re- 

 lating to the acceleration of vulcanization was initiated in order to 

 reduce the time and therefore the cost of vulcanizing. We have 

 seen that the use of compounding materials originated from motives 

 still more mercenary — namely, the desire to make a pound of rubber 

 go farther; but as a result of these two developments and from the 

 work on retarding deterioration, enormous sums have been saved 

 to the consumer. Tliis is not because the investigators merely 

 achieved their original objectives, but because in attacking problems 

 which were worth while in themselves and which were fundamental 

 to the industry, they obtained unexpected and unlooked-for quality 

 advantages far in excess of the original goals toward which they 

 worked. 



INDUSTRIAL USB OF LATEX 



The Indians manufactured ponchos and crude forms of footwear 

 directly from latex, but there was no industrial application of latex 

 in the rubber manufacturing countries until after the World War. 

 The plantation industry had meanwhile developed to the point where 

 it was feasible to ship rubber in this form on a large scale. By the 

 direct use of latex, an improvement has been made in the manu- 

 facture of certain types of rubber goods. Also, industries which 

 have heretofore been unable to use rubber now find it feasible to 

 incorporate it in the form of latex in certain products. 



In the manufacture of rubber goods, latex is frequently used in 

 place of organic dispersions of rubber for the manufacture of dipped 

 goods, such as gloves, and of spread-sheet products. It is also em- 

 ployed for treating tire cords and other textiles used in the manu- 

 facture of rubber goods. 



One of the most interesting applications is the direct manufacture 

 of rubber thread from latex. We have already referred to the 

 methods used by Hancock, whereby threads were cut direct from 

 biscuits of fine Para. After the discovery of vulcanization this 

 method was superseded by one in which the rubber, sulfur, and other 



