US2443322A - Emulsification of coal tar pitch - Google Patents

Description

Patented June 15, 1948 UNITED STATES ATENT OFFICE EMULSIFICATION OF COAL TAR PITCH of Great Britain No Drawing. Application February .6, 1945, Se-

rial 1943 2 Claims.

This invention relates to the controlled preparation of aqueous emulsions of coal tar pitch.

Heretofore it has not been considered to be commercially practicable to emulsify unselected coal tar pitch having a melting point above 50 C., and having a working fluidity only at a temperature above 100 0., notwithstanding that such coal tar pitch has a wide field of application in the coating or impregnation of paper and paper board.

In seeking to emulsify coal tar pitch from different sources by the process described in the specification of British Patent No. 462,111, we have occasionally obtained irregular results, due to variations in the chemical and physical properties of such pitches even when of substantially the same melting point and comparable fluidity.

As the result of experimental research we have now found that the irregular results mentioned above can be largely eliminated by using natural asphalt, such as Trinidad asphalt, as an assistant emulsifier in the emulsification of coal tar pitch, it may be in conjunction with a proportion of fatty acid pitch or fatty acid, and dispersing the blend in a hot dilute aqueous solution of an alkali, preferably a fixed alkali, employing as an additional assistant emulsifier a protein compound, with or without the presence of an organic salt or salts, for example, sodium oleate, with or without the presence of a colloidal clay such as bentonite.

For the purpose of our invention the Trinidad asphaltmay be blended (a) with the coal tar pitch before the addition of fatty acid or fatty acid pitch, or (b) with fatty acid or fatty acid pitch before its addition to the coal tar pitch.

Emample the alkali refining of linseed oil. When linseed oil is treated with hot aqueous alkali, the free fatty acids present in the linseed oil are saponi- It is a by-product of Lil No. 576,512. In Great Britain December 2,

2 fled and are dissolved in the aqueous medium in which the alkali was dissolved. On standing, the aqueous and oleaginous phases resolve into lower and upper layers, respectively. The aqueous phase after being separated is acidified with sulfuric acid to precipitate the free fatty acids and two layers again form. The oleaginous layer is linseed acid oil, the approximate composition of which is:

Per cent Linseed-oil-free fatty acids Tcontained in the original linseed oil) Entrained linseed oil 40 Mucilage and water 10 We claim: 1. The process of producing an aqueous emulsion of a coal tar pitch having a melting point above 50 C. and a working fluidity only at a temperature above C., which comprises blending the coal tar pitch with an assistant emulsifier comprising Trinidad asphalt and linseed acid oil, and dispersing the blend of coal tar pitch, Trinidad asphalt and linseed acid oil in a hot dilute aqueous alkaline solution.

2. The process of producing an aqueous emulsion as defined by claim 1, in which 10 parts by weight of Trinidad asphalt and 7.5 parts by weight of linseed acid oil are blended with each 100 parts by weight of coal tar pitch.

JOHN ALEXANDER MONTGOMERIE. PE'IER KENNEDY ARCHIBALD. LEONARD CHARLES BRADSHAW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,190,604 Montgomerie et al. Feb. 13, 1940 1,734,437 Kirschbraum Nov. 5, 1929 1,725,648 Kirschbraum Aug. 20, 1929 FOREIGN PATENTS .Number Country Date 462,111 Great Britain Mar. 2, 1937 421,269 Great Britain Dec. 6, 1934 332,591 Great Britain July 22, 1930 28,178 Great Britain 1910 670,870 France Aug. 26, 1929 665,060 France Apr. 30, 1929 134,983 Austria Oct. 25, 1933