CHAPTER II 

 A STUDY OF DRIERS AND THEIR EFFECT 



THE proper drying of oils and their behavior with various 

 siccatives in varying quantity is an interesting problem, and ob- 

 viously of considerable importance from a practical standpoint. 

 Unfortunately there is a decided scarcity of reliable literature 

 dealing with the subject for the guidance of those concerned 

 in the manufacture or application of siccative products. Further- 

 more, when the problem is investigated, it is not difficult to see 

 why this is so. 



Uniform Conditions. At a glance it is evident that a decided 

 obstacle in experimentation on the drying properties of oils is 

 the difficulty in obtaining identical conditions for comparative 

 purposes. Inasmuch as a multitude of factors, such as uni- 

 formity and homogeneity of the driers and the oils themselves, 

 intensity and source of light, temperature, uniformity of applica- 

 tion, and many others, play a decisive part in the siccative 

 tendencies of oils, the resources and ingenuity of the chemist 

 engaged in the research are severely taxed. 



Oxygen Absorption. It is a well-known fact that linseed oil, 

 when applied to a clean surface, such as a glass plate, will undergo 

 oxidation and take up oxygen to the extent of about 16%, 

 forming a hard, elastic, non-sticky product which has been 

 called linoxyn. This material, unlike the oil from which it 

 has been formed, is insoluble in most solvents. Other oils, 

 such as cottonseed, hemp, rape, olive, etc., are more fully satisfied 

 in nature and have not the power to absorb the amount of oxy- 

 gen taken up by linseed oil. 



In carrying out the following tests, on the drying of oils, a 

 quantity of pure linseed oil of the following analysis was secured: 



Specific gravity at 15 C 0.934 



Acid number 5 



Sappnification number 191 1 



Iodine number 188 



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