8 



PAINT TECHNOLOGY AND TESTS 



acids, is secured by crushing, steaming and pressing the seed. 

 There are several varieties of the plant, and they are said to be 

 the best annual legume for forage, the straw and fruit being rich 

 in nitrogen and very fattening as a cattle food. Soya may be 

 grown in nearly any country and is a great carrier of nitrogen 

 to land deficient in this element. Although the oil has been 

 used abroad for many years for soap-making purposes, its use as 

 a drying oil is comparatively recent; being introduced into the 

 paint industry of the United States during the year 1909, when 

 linseed oil started on its phenomenal rise in price. 



The oil has given fair service in some paints when mixed with 

 upwards of 75% of pure linseed oil. It is of a semi-drying nature, 

 but may be made to dry rapidly when mixed with manganese 

 and lead linoleate driers. By compounding it under heat with 

 tung oil and rosin, a substitute for linseed oil is produced, which 

 some claim to be quite valuable. 



Table I gives the constants of several samples of soya oil examined by the 

 writer. Table II shows the iodine value of mixtures of soya and linseed oils. 

 Table III shows the results of drying experiments on soya oils containing 

 different percentages of lead and manganese driers. 



TABLE I 



CHEMICAL CHARACTERISTICS OF SOYA BEAN OIL 



TABLE II 

 IODINE VALUES OF LINSEED OIL AND MIXED OILS 



