قراءة كتاب Paint Technology and Tests

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Paint Technology and Tests

Paint Technology and Tests

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دار النشر: Project Gutenberg
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industry.

The analyses of samples of whale oil tested by the writer are as follows:

  Sp. Gr. Iodine
Value
Saponification
Number
Free Fatty
Acid
Light Refined .924 148 190 .2 1.2
Dark Yellow .920 142 187   7.0
Dark Brown .910 140 184   18.0

Sunflower Oil. Sunflower oil is produced largely in Russia and Hungary, finding favor in those countries as an edible oil. The ripe seeds of the sunflower plant contain over 30% of oil which is very pale in color and of a pleasant smell. It has been found that sunflowers may be grown to advantage in dry parts of the United States, and if suitable yields are obtained from a few experimental acres now being cultivated, the industry may receive encouragement in this country. The oil should be well suited for varnish making, and although the iodine number is not very high, it dries quite rapidly.

Russian Sunflower Seeds

Russian Sunflower Seeds

Constants of Sunflower Oil
Sp. Gr. Iodine No. Saponifica-
tion No.
Acid
No.
.929 128 188 4

Cottonseed Oil. This oil is expressed from the seed of the cotton plant, varying in color according to the time of its pressing and degree of refinement. Being edible as well as highly suited for soap making, very little of it comes into the market as a paint oil. It contains large quantities of stearin and has a low iodine value, making it a slow drying oil. Some samples are extremely light in color and contain less mucilaginous matter and foots than is present in ordinary varieties.

Constants of Cottonseed Oil
Sp. Gr. Iodine No. Saponifica-
tion No.
Acid
No.
.922 106 190 2.4

Corn Oil. As a by-product in the manufacture of starch and alcoholic liquids, this material comes into the market having a golden yellow color, and an odor resembling fermented grain. It has a lower drying value than cottonseed oil, and its use in the paint industry will probably be limited to color grinding, where an oil with a semi-drying value is often desired. Like cottonseed oil, it belongs more properly to the soap oil class. It contains glycerides of linoleic and especially palmitic acid.

Analysis of Corn Oil
Sp. Gr. Iodine No. Saponification No. Acid No.
.925 118 191 9.5

Rosin Oil. By the dry distillation of rosin, there is yielded a series of heavy dark oils consisting principally of hydrocarbons, resinous bodies, and free acid. These oils vary in their saponification number from 10 to 60, while their unsaponifiable value averages about 80. Of the grades termed first, second, third, and fourth run, the latter two are superior for use in paints, as a rule containing less free acid than the preliminary runs. Treatment with steam and alkali serve to neutralize the acid nature of the oils and to remove impurities. Refined oils are lighter in color and are often blown and bodied to fairly rapid drying products, especially when treated with manganese driers. Rosin oils are seldom used with lead pigments, on account of the presence of sulphur in the oils, which would result in darkening. Rosin oil paints work very smoothly, even when they are curdled, producing glossy surfaces. The rapid checking of rosin oil paints on wooden surfaces bars the use of this oil for such purposes.

Analyses of Rosin Oils
  Sp. Gr. Iodine
Value
Saponifica-
tion No.
Acid No.
A .96 6 41 27 16.7
B .99   48 38 10.0

Hydrocarbon Oils. Several grades of neutral or mineral oils, varying somewhat in gravity, color, and quality, are produced as the last distillate in the refining of petroleum. These oils when mixed with drying oils and strong driers find application in the manufacture of some freight-car, barn, and other paints which sell at a low price. A small percentage of mineral oil is said to be valuable in structural steel paints, acting as a preventative of hard drying and thus keeping the film soft and elastic. Streaking and sweating is apt to ensue if any great quantity is used. Mineral oils have a characteristic bloom, showing a greenish fluorescence when examined by transmitted light. This bloom is due to the presence of some strongly fluorescent material which is shown up with intensity when mineral oils are exposed to ultraviolet rays such as emanate from an enclosed arc light. Outerbridge[1] first proposed this test for mineral oils, and he has worked out a “fluorescent scale,” by which very small percentages of hydrocarbon oils may be detected in other oils. Several types of so-called debloomed oil have been placed upon the market, and although such oils appear under ordinary light conditions to be free from bloom, they

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