US2324473A - Method of preparing bituminous emulsions - Google Patents

Description

ll atenterl July 20, W43

METHOD OF PREPARING BITUMINOUS EMULSIONS John J. Allinson, El Dorado,- Ark., assignor to Lion Oil Refining Company, El Dorado, Ark., a corporation of Delaware No Drawing.

Application January 29, 1940,

Serial No. 316,214

3 Claims.

sions, and with regard to certain more specific features, to bituminous paving emulsions.

Among the several objects of the invention may be noted the provision of a bituminous paving emulsion of the class indicated, wherein the continuous phase is water and the dispersed phase is an asphaltic composition, which emulsion is of exceedingly stable character, and shows substantially no tendency whatsoever to form asphalt pellets therein: the provision of an emulsion of the class described which is simple and economical to manufacture; the provision of a simple and economical method of making emulsions of the class described; and the provision of a reliable method for preventing pellet formation in bituminous paving emulsions of the class indicated. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, the proportions thereof, steps and sequence of steps, and features of composition and manipulation, which will be exemplified in the substances, products, and methods hereinafter described, and the scope of the application of which will be indicated in the following claims.

Bituminous paving emulsions of the class heretofore indicated, when made from certain types of rosins, have heretofore been undesirably unstable in character, in that, probably due to the surface tension of the asphalt constituent, the dispersed asphalt phase tends to coalesce into pellets which not only settle out themselves but appear to promote the formation of more and more pellets until the entire emulsion is broken. This is also true when a standard rosin soap is used as an emulsify ng agent in the emulsion. This undesirable feature has heretofore caused the rejection of many readily available and cheap asphalts as raw materials for making paving emulsions.

The present invention also concerns a method of preparing emulsions using such asphalts, which do not exhibit the aforementioned tendency to form pellets.

Broadly speaking, the present invention is based upon the discovery that if the asphalt constituent of the emulsion prior to emulsification, is modified by the addition thereto of a small proportion of a lighter non-adjacent petroleum fraction, and the resulting modified asphalt is then emulsified with water, as in a colloid mill or any other type of dispersing machinery, the resulting emulsion will be smooth and will not This invention relates to bituminous emulexhibit the pellet formation phenomena heretofore described, but on the contrary will be stable over long periods of time.

Because the addition of the lighter fraction tends to reduce the hardness, or increase the penetration, of the asphalt constituent, it is desirable that such an asphalt constituent be reduoed, initially, to a lower penetration, or greater hardness, than would ordinarily be the case with that asphalt, In this way, the modified asphalt, containing the lighter fraction, as actually used for making the emulsion, has the desired penetration or hardness, and the final paving will likewise have the desired penetration or hardness.

Apparently th present invention applies to all petroleum asphalts which show the aforementioned tendency to form pellets. Among the various asphalts which show such tendencies, and which have satisfactorily been emulsified in accordanc with the present invention, are a Schuler (near El Dorado, Arkansas) vacuum reduced asphalt, of to rum/1o penetration (100 grams, 5 seconds) at 77 F., an Urbana asphalt of 85 to 250 mm. penetration (100 grams, 5 seconds) at 77 F., a Panuco Mexican asphalt of 55 to 100 mm./10 penetration (100 grams, 5 seconds) at 77 F., and certain asphalts from Oklahoma of penetrations up to 300 mar/1o (100 grams, 5 seconds) at 77 F. It will be understood, of course, that these asphalts are by way of example only, and that the penetration ranges for the various asphalts that may be satisfactorily treated in accordance with the present invention may be considerably in excess of those stated.

The added lighter non-adjacent petroleum fraction is usually a petroleum fraction between the boiling ranges of kerosene and of lubricating oil, inclusive, and 'thus includes ker'osenes, gas oils and lubricating oils. The particular lighter fraction selected depends upon the desired characteristics of the final emulsion, and the char acteristics of the asphalt raw material. Ordinarily, for best results, the lighter fraction should constitute from one-half to ten per cent, more or less, of the modified asphalt as it is prepared in condition to be emulsified.

The lighter non-adjacent petroleum fractions which have been used with greatest success are lubricating oil fractions which have universal viscosities at 100 F. of not less than '75 seconds and not more than 700 seconds. Distillation of such fractions cannot be obtained at atmospheric pressure, but on the average it is known that not over thirty per cent. will be distilled over at 680 F. when the American Society for Testing Materials procedure 1380-30 is followed. The fiash point is usually over 300' F.

Occasionally a lighter fraction such as a gas oil or even kerosene can be used. The lightest or most volatile material which has yet been used with satisfaction is a kerosene fraction which has an initial boiling point of 336 I". and an end point of 502 Ewhentested according to the the same crude oil as the asphalt used.

In finally emulsifying the modified asphalt, the usual procedure and substantially the usual proportions are used. That is to say, in the final emulsion, themodified asphalt content is usually from forty to seventy-five per cent., by weight, and the water is sixty to twenty-five per cent., by weight.

The emulsification may be facilitated, and the stability of the. resulting emulsion improved, if an emulisfying agent, such as a soap. be used in making the emulsion. Any suitable soap, the

types of which are well-known in the art, may be used. One satisfactory type of soap comprises that made by reacting a caustic alkali (either potassium hydroxide or sodium hydroxide) with a pine rosin. A typical soap is made by reacting test. The resulting emulsion is exceedingly smooth and stable.-

Emmple Z This is a so-called slow-break emulsion for paving.

The modified asphalt constituent of the emulsion consists of ninety-five per cent., by weight, of an asphalt having a penetration of 87 mmJie (100 grams, 5 seconds) at 77 F., and five per cent., by weight of a lubricating oil fraction having a universal viscosity of 605 seconds at 100 F. The penetration of the resultant modified asphalt (100 grams, 5 seconds).is 160 mmJm at 77 F. Prior to the emulsification procedure, this modified asphalt constituent is preferably brought to a. temperatur of 260 F.

The water phase for the emulsion is preferably modified by the addition thereto of five per cent.

one part of pine rosin with about 0.18 part of potassium hydroxide. The soap so made is ordinarily diluted with water, and then is added to the water to be used for emulsification, in proportions amounting to between one-half per cent. and five per cent. by weight of this emulsification water. Naphthenic soaps may also satisfactorily be used. I

It is tobe understood, however, that the soap is not an essential, albeit desirable, constituent of the emulsions of the present invention.

The following are typical but non-limiting examples of emulsions made in accordance with the present invention:

Example 1 This is a so-called "fast-break" emulsion, pav n purposes.

The modified asphalt constituent for the emulsion comprises a thorough mixture of 97.5 per cent., by weight, of an asphalt having a penetration of 77 mm./io (100 grams, 5 seconds) at 77 F.; and two and one-half per cent., by weight, of a lubricating oil fraction having a universal viscosity of 275 seconds at 100 F. The penetration of the resultant modified asphalt is 160 mm./m (100 grams, 5 seconds) at 77 1''.

The water for the emulsion is modified by the addition thereto of approximately 1.2 per cent. of its weight of a soap consisting of the reaction products of potassium hydroxide and the socalled "Hercules F. F." rosin, which is a distillate for ' of pine rosin having a melting point of about of the weight of the water, 'of a soap made by reacting Hercules Vinsol rosin with potassium hydroxide. The Hercules Vinsol" rosin is the still residue from a pine rosin distillation. It has a melting point of approximately 111 C., and a saponification number of about 150. The soapcontaining water phase is preferably brought to a temperature of F. for the emulsification.

Emulsification is brought about in a colloid mill which is set to 0.005 inch. The modified asphalt phase of the emulsion constitutes about sixty per cent., by weight, of the total emulsion. The universal viscosity of the finished emulsion, at 77 F., is about 20 seconds. About 0.1 per cent., by weight, of the emulsion is retained on the screen in the standard American Society for Testing Materials sieve test. The emulsion is smooth and stable, and eminently satisfactory for road building purposes.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above methods and substances and products without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. The method of preventing pellet formation in bituminous paving emulsions of the asphaltin-water type, which comprises reducing an asphalt of relatively high penetration, which in aqueous emulsions tends to form pellets through coagulation of previously dispersed particles, to a penetration not substantially below approximately 77 mm./io (100 grams, 5 seconds) at 77 F., and then mixing with said asphalt prior to its emulsification, substantially to 10 per c nt, by weight of a petroleum fraction of boiling range substantially between the lower boiling point limit of kerosenes and the upper boiling point limit of lubricating oils, said asphalt being of such nature that, if emulsified in the absence of said reduction and mixing, pellet formation will occur through coagulation of previously dispersed particles.

2. The method of preventing pellet formation in bituminous paving emulsions of the asphaltin-water type, which comprises reducing an asphalt of relatively high penetration, which in aqueous emulsions tends to form pellets through coagulation of previously dspersed particles, to a penetration of approximately 77 mm./1o (100 grams, 5 seconds) at 77 F., and then mixing with said asphalt prior to its emulsification, approximately 2 /2 per cent. of a petroleum fraction of boiling range substantially between the lower boiling point limit of kerosenes and the upper boiling point limit of lubricating oils, said asphalt being of such nature that, if emulsified in the absence of said reduction and mixing, pellet formation will occur through coagulation of previously dispersed particles.

3. The method of preventing pellet formation in bituminous paving emulsions of the asphaltin-water type, which comprises reducing an asphalt of relatively high penetration, which in aqueous emulsions tends to form pellets through coagulation of previously dispersed particles, to a penetration of approximately 87 mm./ia (100 grams, 5 seconds) at 77 F., and then mixing with said asphalt prior to its emulsification, approximately 5 per cent. of a petroleum fraction of boiling range substantially between the lower boiling point limit of kerosenes and the upper boiling point limit of lubricating ols, said asphalt being of such natur that, if emulsified in the absence of said reduction and mixing, pellet formation will occur through coagulation of previously dispersed particles.

J. J. ALLINSON.

Certificate of Correction Patent N 0. 2,324,47 3.

July 20, 1943.

JOHN J. ALLINSON It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, second column, line 13, claim 3, for 015 read oils; and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 7th day of October, A. D. i947.

THOMAS F. MURPHY,

Assistant Uommiss'o'ner of Patents.

Certificate of Correction Patent No. 2,324,473. July 20, 1943.

JOHN J. ALLINSON It is hereby certified that error appears in the printed specification of the above numbered patent requirin correction as follows: Page 3, second column, line 13, claim 3, for 01s read 0' s; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 7th day of October, A. D. 1947.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.