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قراءة كتاب Paint Technology and Tests
تنويه: تعرض هنا نبذة من اول ١٠ صفحات فقط من الكتاب الالكتروني، لقراءة الكتاب كاملا اضغط على الزر “اشتر الآن"
specific gravity is observed. The following analyses of various types of linseed oil were recently made by the writer:
| Pure Raw Linseed Oil |
Boiled L. O. (Linoleate) |
Boiled L. O. (Resinate) |
Blown L. O. |
Litho. L. O. |
Old Treated Oil |
|
| Color | Amber | Dark | Reddish | Pale | Dark | Amber |
| Clear | Brown | Brown | Brown | Clear | ||
| Sp. Gr. at 15° C. | .933 Average |
.941 | .930 | .968 | .970 | .943 |
| Iodine No. | 180 | 172 | 176 | 133 | 102 | 172 |
| Saponification No. | 191 | 187 | 186 | 189 | 199 | 197 |
| Free Fatty Acid | 3.2 | 2.7 | 2.2 | 2.8 | 2.7 | 6.9 |
| Unsaponifiable | 1.4 | — | — | — | — | 1.8 |
| Maumene | 111 | — | — | — | — | 96 |
| Moisture | .2% | — | — | — | — | none |
Soya Bean Oil. The soya plant which is extensively cultivated in Asia produces a seed bearing up to 22% and over of a golden colored oil having a peculiar leguminous odor. The oil, which probably consists of the glycerides of oleic, linoleic, and palmitic 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
| Sample No. | Specific gravity | Acid No. | Saponification No. |
Iodine No. | Per cent. of foots |
| 1 | 0.9233 | 1.87 | 188.4 | 127.8 | 3.81 |
| 2 | 0.9240 | 1.92 | 188.3 | 127.2 | — |
| 3 | 0.9231 | 1.90 | 187.8 | 131.7 | — |
| 4 | 0.9233 | 1.91 | 188.4 | 129.8 | — |
| 5 | — | — | — | 130.0 | — |
| 6 | — | — | — | 132.6 | — |
| 7 | — | — | — | 136.0 | — |
| Average | 0.9234 | 1.90 | 188.2 | 130.7 | — |