US2915450A - Process for the preparation of hydrocarbon wax compositions comprising deoiling a blend of slack and soft waxes - Google Patents

Description

Dec. 1, 1959 PROCESS FOR THE PREPARATI OLSON ON OF HYDROCARBON WAX COM POSITIONS Filed Sept. 11, 1957 AROMATICS SOLVENT CUT A 2 3 5 HEATER CHILLER WAXY cum SEPARATOR A :9

on. 8 v

- PUMP cum 4 DISTILLATION A o A m c R M T s OLUMN ,7 FILTER lo SOLVENT RECOVERY DEWAXED on.

T0 STORAGE SLACK wAx HEATER CHILLER I '9 V, V/ SLACK WAX A8 SOLVENT SOFT RECOVERY SOFT wAx wAx MICROCRYSTALLINE LENDER 0R SOLVENT PARAFFIN WAX RECOVERY 40 SOLVENT RECOVERY HEATER DUCTILE 2| CHILLER 25 FILTER 0R LOW F 23 SOLVENT E TEMPERATURE 22 v v' 24 RECOVERY wAx INVENTOR= HIS AGENT ROBERT J. OLS N United States Patent PROCESS FOR THE PREPARATION OF HYDRO- CARBON WAX COMPOSITIONS COMPRISING DEOILING A. BLEND OF SLACK AND SOFT WAXES Robert J. Olson, Houston, Tex., assignor to Shell Development Company, New York, N.Y., a corporation of Delaware Application September 11, 1957, Serial No. 683,249

5 Claims. (Cl. 20831) This invention relates to the art of preparing hydrocarbon wax compositions. More particularly, it pertains to the preparation and recovery of hydrocarbon petroleum waxes showing improved ductility, flexibility and low temperature resistance to shock chilling. Still more specifically, it pertains to the preparation of such waxes by the inclusion of certain soft waxes normally eliminated during the dewaxing processes previously known in the art.

Various methods have been used and suggested for the recovery of paraflin waxes and microcrystalline waxes from mineral oil distillates and residues. Thus, it is known to dewax waxy mineral oils or fractions thereof by cooling, usually after addition of a solvent and/or diluent. Dependent upon the nature of the oil and the conditions of the operation, such as the lowest cooling temperature, rate of cooling, manner of cooling, etc., the waxes so obtained have certain shortcomings which it would be desirable to correct. Certain steps in this direction have been taken by the recovery of soft wax components in the soft wax fraction usually rejected during a deoiling step.

The separate deoiling of the soft wax fraction is normally attended by difiiculties due, for example, to the low melting point of the waxes involved and to the relatively low wax content inthe soft wax fraction. Because of this, it has been found that the wax cake produced during the dewaxing of a soft wax fraction is prone to crack and thereby present increased difficulties in washing out the oil from which it should be separated. Thus, deoiled soft waxes produced by previously known methods normally contain unduly great proportions of oil which cause a degradation in the quality of the wax. Moreover, during the deoiling of a soft wax by previously known methods, a number of the most desirable types of highly ductile low melting soft waxes are eliminated in the oil-containing solvent solution. Thus, the fractions which might be of greatest aid in increasing the ductility and low temperature characteristics of waxes are lost. Moreover, the soft wax fraction, due to ditficulty in satisfactory dewaxing thereof is normally sent to cracking or otherwise disposed of under such circumstances that its rated dollar value is extremely low as compared to commercial grade hydrocarbon waxes. Hence, any process which results in a usable recovery of soft waxes otherwise sent to cracking or otherwise disposed of results in a corresponding increment in the value of the dewaxing process.

In the deoiling of slack waxes steps have previously been taken to incorporate insofar as possible soft wax fractions by lowering the temperature of deoiling to such a point that the soft waxes crystallize with the higher ICC melting point wax fractions. While it is thus possible to segregate a certain proportion of the soft Waxes, the use of the low deoiling temperature also causes an increase in the viscosity of the oil from which the waxes must be separated. Because of this increase in viscosity the oil tends to be retained upon the surfaces of the wax crystals and thus the product so obtained is often found to have too great a proportion of oil present. Moreover, it will be seen that if the low temperature deoiling of slack waxes is utilized as a method for retaining insofar as possible the soft waxes normally disposed of in the filtrate of a deoiling operation, the result is limited by the proportion of soft waxes naturally occurring in the Waxy oil stock being treated. Hence, if the proportion of soft waxes is either unduly high or unduly low it will be found that the resulting mixture of hydrocarbon waxes will not meet specifications set out by users of the Waxes such as milk carton manufacturers, paper coating manufacturers and the like.

Another disadvantage of the separate deoiling of soft Waxes (in order to be independent of this fixed naturally occurring ratio of soft waxes to other waxes) comprises the necessity for maintaining a multiplicity of storage facilities for the segregation of the various stocks.

It is an object of the present invention to improve the processes for the preparation of wax compositions. It is another object of this invention to improve the low temperature properties of hydrocarbon waxes. It is a particular object of the present invention to provide a process for the preparation of wax compositions exhibiting improved resistance to cracking upon shock chilling. It is another particular object of this invention to provide a process for the improvement in ductility of microcrystalline waxes. Other objects will become apparent during the following discussion.

Now in accordance with this invention, it has been found that improved wax properties, especially at low temperatures, may be obtained by including in the wax compositions wax components in essentially the same boiling range as ordinary paraffin waxes or microcrystalline waxes present in the compositions but which are normally lost in deoiling operation. More particularly, an improved process for the preparation of wax compositions having improved flexibility, ductility and resistance to cracking upon shock chilling comprises dewaxing a waxy petroleum oil to obtain a slack wax, deoiling the latter to obtain a deoiled wax and a soft wax, combining the soft wax with further proportions of the same slack wax and deoiling the combined mixture of waxes.

The foregoing objects and others as well as the process of the present invention will be better understood by reference to the accompanying drawing wherein Fig. 1 is a typical arrangement of apparatus for carrying out the process of the present invention in preparing an improved paraflin wax composition.

Referring now to Fig. 1, a waxy oil contained in a storage tank 1 is conveyed to a distillation column 2 wherein the oil is separated in fractions according to boiling point ranges, one of which may be designated cut A. This is conveyed by means of line 3, being pumped by pump 4 to a point where it is mixed with a selective solvent for aromatics coming from storage tank 5. The mixture is passed to a separator 6 wherein a solution of the aromatics is separated and removed, the waxy rafiiuate being mixed with a dewaxing solvent from the solvent recovery tank 7 and passed to a heater chiller 9 where waxes present in the mixture are crystallized.

The wax-solvent-oil mixture is passed to a filter 10 for the separation of the waxes from the remaining components of the mixture. The filtrate comprises a dewaxed oil dissolved in a solvent which is then passed to a solvent recovery system 7 from which a dewaxed oil is passed to storage. The slack wax remaining on the filter comprises a mixture of the waxes present in the waxy oil contaminated by 260% by Weight of oil. This mixture is conveyed by pump 11 to a point in line 12 where it is mixed with a deoiling solvent from a solvent recovery system 13 and then passed to a heater 14 to dissolve the slack wax in solvent. Thereafter, it is passed to chiller 15 for precipitation of wax and the wax so precipitated is recovered on the filter in filter 16.

The filtrate from filter 16 comprises a solution of a soft wax contained in the solvent. This solution is passed by means of pump 17 to the solvent recovery system 13 wherein the solvent is separated from the soft wax. The soft wax is then passed by means of line 18 to a blender 19 wherein it is blended in suitable proportions with further proportions of slack wax from the filter 10. Ordinarily the proportions of the blended materials will be 3-5 volumes of the slack wax and 1-5 volumes of the soft wax. Solvent-from the solvent recovery 13 or elsewhere is then added to the blend which is transmitted by means of line 20 to the heater 21 wherein the slack wax-soft wax blend is substantially completely dissolved in a deoiling solvent and passed by means of line 22 to a chiller 23 wherein the mixture of waxes and soft Waxes are precipitated from any oil present, the oil being dissolved in solvent. The mixture is passed through line 24 to the filter 25 to remove the precipitated waxes, the solution of oil and solvent being sent to solvent recovery system 26. Traces of solvent are removed from the filtered and separated waxes in the solvent recovery system 27, thus resulting in the production of a wax having improved low temperature properties or, in the case of microcrystalline waxes particularly, improved ductile properties.

In the case of microcrystalline wax compositions especially, it may be desirable to process this particular wax product still further such as by a high temperature Wax sweating or high temperature solvent deoiling operation to obtain a relatively high melting hard wax on one hand and a more ductile adhesive microcrystalline wax composition on the other. Applying the system of apparatus illustrated in Fig. 1 to the processing of microcrystalline wax compositions it will be understood that the microcrystalline waxes normally occur in residual oils and hence, would be derived from a point at the lower end of the distillation column 2 rather than from one of the distillate cuts, namely, cuts A or B indicated on distillation column 2.

By the above description, it can be seen that the principal object of the present invention is to incorporate soft waxes normally lost in the filtrate from filter 16 of Fig. 1. The same object cannot be accomplished to nearly the same extent by sending the soft waxes back to a point in the apparatus prior to the preparation of the slack wax since these soft wax fractions then would be removed in large part in the dewaxed oil, thus, undesirably raising the pour point of the oil and preventing utilization of the soft waxes in the wax compositions where they are desirable. While the conditions well known in the art for dewaxing may be employed, it is preferred that relatively low dewaxing temperatures be utilized. However, the benefits of the present invention are also obtained when ordinary dewaxing temperatures are present.

The waxy petroleum oils which may be treated according to the process of the present invention comprise 2,915,450 Y e e either distillate petroleum fractions, particularly the distillate lubricating oil fractions, as well as residual oils such as short residues and the like. It is well known that the paraffin waxes exist largely in the distillate fractions (with the exception of the high melting point paraffins which may be present in the residues), while the microcrystalline waxes are normally found in the residual oils either alone or in combination with any melting point parafiins which may be present. The proportions of waxes in these fractions are well known in the art. The major components of the present compositions insofar as they are paraffin wax-containing petroleum oils comprise normal, iso-paraffin and cycloparafiin hydrocarbon waxes having individual melting points within the usual range from about l10165 F., more normally between about -145 F. The distillate paraffin waxes usually predominate in normal paraflins and may comprise a single wax but ordinarily will be a mixture of relatively closely related paraffin waxes. The general practice is to distill a broad lubricating oil fraction which may be dearomatized either prior to or subsequent to redistillation for the preparation of relatively narrow boiling range waxy oil cuts.

The residual oils normally comprise what is known as bright stock which is a high viscosity residual lubricating oil combined together with microcrystalline waxes, any high melting point paratfin Waxes which may occur and, if a mixed base crude is being treated, asphaltic fractions. Asphalts may be removed by propane extraction or by other means prior to dewaxing operations.

The initial dewaxing operation is by means of selective solvents which are well known in the art. In carrying out the improved process of the present invention, the dewaxing and deoiling operations are accomplished by chilling the Waxy oils together with oil solvents or diluents including, for example, ketones of less than about 8 carbon atoms per molecule such as acetone, methylethyl ketone, methyl propyl ketone, methyl isobutyl ketone, etc.; alcohols having less than about 8 carbon atoms per molecule such as ethyl alcohol, isopropyl alcohol, normal propyl alcohol and the like. Petroleum naphthas, halogenated hydrocarbons, such as ethylene dichloride and dichloroethylene; hydrocarbons having less than about 8 carbon atoms per molecule such as benzene, toluene, ethane, ethylene, propane, propylene, butane, isobutane, etc. Mixtures of solvents or diluents such as benzene together with methyl ethyl ketone may be employed as disclosed in prior art dewaxing processes.

Solvent dewaxing and deoiling may be carried out at temperatures which are well known and with proportions of solvent to waxy oil or oily wax which are known in the art. Dewaxing temperatures when using polar solvents are usually in the range from about l5 F. to +15 F., the dewaxing solvents (polar or non-polar) being present in amounts from about 1 volume to 5 volumes per volume of waxy oil. The dewaxing temperature range when utilizing lower molecular weight alkanes only (e.g. propane) are usually between about 40 F. to about 0 F. Dewaxing usually results in the formation of a dewaxed oil and a slack wax, the latter term being applied to the wax product contaminated with a greater or lesser amount of oil or oil-like constituents. The slack wax normally contains from about 2 to about 60% by weight of oil but this figure may vary broadly. In deoiling operations the proportion of solvent is normally increased to between about 2 and 7 volumes of solvent per volume of oily wax, deoiling temperatures being usually between about 32 F. and 65 F.

The soft wax fractions are normally eliminated in the filtrate from the deoiling of slack waxes insofar as they apply to distillate wax production.

The soft waxes comprise mixtures of highly branched or naphthenic waxes having substantially lower melting points and other more plastic properties than those of the more nearly straight chain waxes of the same molecule weight. Consequently, within a given narrow boiling range there may be high melting waxes which are typical paraffin waxes as well as low melting waxes which approach the subject wax fractions normally eliminated as the filtrate from the deoiling of a slack Wax. Consequently, the boiling range of the waxes in the soft wax fraction are roughly co-extensive with the boiling range of the parafiin waxes or microcrystalline waxes naturally existing within the same petroleum oil fraction being processed.

The soft wax members can best be described by reference to a particular example wherein the soft waxes were deoiled to obtain what may be referred to as plastic wax. A waxy lubricating oil distillate boiling within the range from about 650 F. to about 950 F. (at atmospheric pressure) is subjected to solvent dewaxing by means of known selective dewaxing solvents. Preferably this comprises the combination of a low molecular weight aliphatic ketone and an aromatic hydrocarbon such as benzene or toluene in volume proportions of 3:1 to 1:3 (preferably 2:1 to 1:2). More specifically, a preferred pair of dewaxing solvents comprises methyl ethyl ketone and toluene in proportions of between about 2:1 to 1:2 by volume. A suflicient amount of the de waxing solvent is employed to completely dissolve the waxy lubricating oil at temperatures in excess of about 120 F after which the solution is cooled to a dewaxing temperature, preferably in the order of between about to +15 F. when using polar solvents or -40 F. to 0 F. for lower alkane dewaxing solvents. At about the dewaxing temperature, the slack wax is filtered or centrifuged from the dewaxed oil. The slack wax is in turn subjected to a solvent deoiling procedure, preferably using the same type of deoiling solvents. The slack wax is dissolved in the solvents, preferably methyl ethyl ketone mixed with toluene usually at an elevated solution temperature and cooled to a temperature between about 35 F. and about 50 F., at which point the refined paraffin wax is filtered. This paraflin wax is treated in accordance with known procedures, such as by repulping or washing on a filter in order to obtain a fully refined paraflin wax having a melting point between about 135 and about 145 F.

The soft wax mixture left in solution in the solvent is in turn subjected to a deoiling treatment either by cooling the existing solution down to a point where the plastic waxes crystallize or by removing a sufficient amount of the solvent to provide a more concentrated solution of the soft wax, so that more easily attained deoiling temperatures may be employed. Preferably, the soft wax is dissolved in between about 2 and about 6 parts by volume of deoiling solvent per part of soft wax, heated .to a temperature in the order of ll60 F., and cooled to a temperature between about and 40 F., at which point the plastic waxes separate and are removed by mechanical separation such as by centrifuging or filtration. In order to remove the maximum amount of contaminating oil from the precipitated waxes, it is a preferred practice to subject the waxes so obtained to washing or repulping or both within the filtration temperature range in order to obtain the desired plastic wax.

The product so obtained has unique properties not found in any wax described in the prior art. It has a melting point within the range from about 108 to about 117 F., a viscosity between about and 45 SSU at 210 F., a refractive index at 70 C., between about 1.4365 and 1.4500 and an oil content, as determined by the standard ASTM method, of less than about 0.5%. The penetration of the wax at 77 F. is between about and 80 mm./ 10 by ASTM Method D1321-54T.

It will be understood that this constitutes a single example of the plastic waxes to be obtained from the soft waxes rejected in the deoiling of slack wax. It will also be understood that theseplastic waxes are not isolated per se in the process of the present invention but are recycled for combination with further proportions of slack wax from the same petroleum oil out after which the combination of slack wax and soft wax is then deoiled to obtain the wax compositions found to have superior ductility, flexibility and resistance to low temperature shock chilling.

In order to illustrate the process of the present invention the following examples are presented but it will be understood that the invention is not to be limited thereto. In these comparative tests a slack wax was utilized which had been obtained from the dewaxing of an intermediate boiling lubricating oil distillate (from a Texas crude oil) which had been solvent extracted prior to dewaxing operations. The slack wax contained about 8% by weight of oil. In the operation utilized for the comparative testing, the slack wax was subjected to a dewaxing operation using a mixture of methyl ethyl ketone and toluene, the dewaxing temperatures being either 35 F. or 15 F., as indicated in Table 1 which follows. The combination of soft wax so derived when mixed with further proportions of the same slack wax in varying ratios as defined in Table 1 resulted in the production of waxes having improved low temperature properties, also, as indicated in the table.

Sample A represents the process of deoiling a slack wax from an intermediate boiling range lubricating oil out wax at an ordinary temperature (35 F.), yielding a 139.5 F. melting point wax which is relatively hard, relatively inflexible, and tends to crack excessively when shock chilled by cold liquids. The latter property in particular makes this wax unsuitable for coating cardboard containers intended to be filled with cold liquids, as for example, milk.

Deoiling the same slack wax at a relatively low temperature (sample B) yields a product wax which is somewhat softer, more flexible and improved in low temperature fracture resistance properties as compared to the product from sample A. However, the improvement in these properties is limited.

The process of this invention is illustrated in its preferred form by deoiling runs resulting in samples C, D and E. In those experiments 1, 3, and 5 parts of soft wax were added to 4 parts of slack wax and the combination deoiled at a relatively low deoiling temperature (15 F.). The product waxes were relatively soft paraffin waxes showing increased flexibility and little or no cracking in the low temperature fracture test. The product wax would be useful in applications where increased flexibility is advantageous, i.e. in coated bread wrappers or as a coating for frozen food wrappers. It would also be useful as a coating for cardboard cartons to be used for holding cold liquids such as milk or other beverages.

The process is not limited to low deoiling temperatures but is also applicable at ordinary deoiling temperatures, such as 35 F. Deoiling runs producing samples A, F, G and H show how the process is effective at a deoiling temperature of 35 F. As the proportion of soft wax in the feed to deoiling increases from 0 to 1 to 3 to 5 parts of soft wax per 4 parts of slack wax, the product wax from the deoiling operations decrease in melting point and hardness, increases somewhat in flexibility and shows improved low temperature fracture resistance.

This principle, of adding a soft wax back to a slack Wax of the same boiling range, and deoiling the combination together, is applicable to the manufacture of flexible waxes from streams other than the intermediate boiling range stock illustrated here. For example, it is applicable to the lower boiling wax distillate stream where it is desirable to produce a wax having an increased concentration of low melting components. It is applicable to the high boiling distillate stream to produce higher melting point, flexible waxes. It also is applicable to the residual stream, to produce microcrystalline waxes of greater ductility and improved sealing quality.

TABLE 1 Samnle A B C D E F G H Charge Stock Composition:

Slack Wax, Parts 1 1 4 4 4 4 4 4 Soft Wax, Parts 0 1 3 1 3 5 Congcaling Point, F, ASTM D938 131 131 128 124 120 128 124 120 Oil Content Tercent w. ASTM D721 8 8 18 17 21 Laboratory Deoiling Conditions N grmal Lprw Lol w La w L ri w N rli rmal N tl rmal Ng rmal 9111 em em m m Solvent, MEX/Toluene. 50/50 50/5) 50/50 50/5 0 50250 Primary Dilution Ratio 4 4 4 4 4 4 4 4 Secondary Dilution Rati 2 2 2 2 2 2 2 2 Recrystallization Filter Feed Temp, 111. 35 15 15 15 15 35 35 35 Recrystallization Wash Ratio 3 3 3 3 3 3 3 3 Repulp Dilution Ratio a 3 3 3 3 3 3 3 Rcpulp Filter Feed Temp, F. 35 15 15 15 15 35 35 35 Repulp Wash Ratio 2. 5 2. 5 2. 5 2. 5 2. 5 2. 5 2. 5 2. 5 Yield, Percent w.:

Cake 76.8 85.2 74. 3 68. s 68.6 68. 5 57. 7 55. 5 Properties of Product Wax:

Melting Point, F., ASIM D87 139. 5 136.5 135. 3 131.0 127.8 137. a 134. 5 131.8 011 Content, Percent w., ASTM D721 Nil 0.1 0.1 0.4 0.4 Nil Nil 0.1 Hardness, Needle Penetration at 77 mm./10 ASTM D1321 11 13 15 21 13 15 19 Flexibility at 73 F., Angle o Degrees 8 12 17 23 33 16 17 17 Low Temperature Fracture Resistance,

Inches of Cracks 35 25 4. 5 6 lone 2. 5 0. 5

Tests utilized in obtaining the data given in Table l 25 istics which comprises distilling a waxy lubricating oil above may be described as follows: into a plurality of waxy lubricating oil fractions, solvent L I I extracting a fraction having a boiling range between about 0w temperature fracture reszstance test 0 R and F at 760 mm Hg pressure Solvent Five (5) ml. of molten wax at 230 F. is placed in dcwaxing the extracted fraction to produce a slack wax, an unwaxed quart milk carton bottom, allowed to solidify 30 solvent deoiling said slack wax to produce a substantially and the waxed carton bottom conditioned for one hour deoiled paraffin wax and an oil-containing soft wax, at 73 F. and 50% relative humidity. The waxed car- Combining 3 t0 5 Volumes of further Portions fi ton bottom is then shock chilled byimmersion in F. same l k w wi 1 to 5 m s f the oll-contalmns water for one minute, which tends to induce the forma- 9 f and deoiling the mixture to obtain a substantion of cracks. The number of inches of cracks is de- 35 y Oil-free 60111130519011 havlng P 10W termined by measurement with a map mileage gauge. A temperature P p the Wax COmPOYIFmS of said d wax Shows li l or no ki i hi test position derived from the further portions of the slack wax having a boiling range substantially coextensive Wax fl y test with the wax components of the composition derived A specimen of wax 2 inches x 0.5 inch x 0.020 inch from the Soft is cut from a sheet of wax which had been prepared T Process of Waxy lubncatmg 011 previously by solidification on water. The specimen is Stock f dewaxcd lubflcatmg 011 components of 9 conditioned at test temperature for one hour, then mount- P Pomt and Substamlany Parafiin Wax ed in the flexibility testing instrument. The flexibility Improved 10W temPHamIePIOWFtWS Whlch compnses tester consists of two parts, one, a pair of rotatable jaws the Slap? of solvent dewaxmg Bald Stock to Produce a in which one end of the wax specimen is fastened and, sltbstanuauy Wax free 011 and a slack solvent two, a fixed arm to prevent movement of the opposite 011mg f Wax to a Parafiin Wax and an end of the wax specimen in the direction of rotation oll'comemmg soft combmmg 3-5 volumes of the when the jaws are rotated one end at the specimen is latter with 4 volumes of the same slack wax and solvent mounted in the jaws and the jaws rotated to bring the fieolhng the mlxmre whereby a cpmposmor} having opposite end of the Specimen to just touch the fixed improved low temperature characteristics is obtained, the arm. This position is considered the zero point. The f Wax components. Present .composmon havmg a jaws are then rotated at a rate of 0 per minute caus boiling range only w1th1n the boilmg range of the slack ing the wax specimen to bend. The angle at which the Th f specimen cracks is measured by means of a protractor e Proms? Segregatmg a Substantially fee fastened to the jaws. The results of tests on five speci- P i f havmg.1mprqv.d.l0W temperature mens are averaged and reported as the angle of fracture. i Whlch .compnses d1sun mg. a luiancatmg 011 I claim as my invention: into a plurality of waxy lubrlcatmg oil fractions, solvent L The process of segregating a Substantially oiHree extracting one of said fractions solvent dewaxing the expetroleum wax having improved properties which comtracted fractlon to produce .fi t w 011 prises the steps of solvent dewaxing a waxy petroleum oil a a g g Solvent deolhng sald slack ph stock to produce a substantially wax-free oil and a slack uce 2? parafiinlwax and an t i i wax, solvent deoiling a portion of the slack wax to sep- Pg i 3-5 v0 of the Oll'contammg 9 t arate a substantially oil-free petroleum wax from an oily i wlt .volumes of the Same Slack wax and i i soft wax, combining the oily soft wax with 3-5 volumes t e mixture whereby paraffin of the same slack wax and solvent deoiling the mixture, haymg Improved temperature characterisilcs 15 Ohwhereby a wax composition having improved properties t the FPmPOsltlOn so phepfired conigimmg waxes is obtained, the soft wax components of the composition q bolhng range only Wlthlfl I116 oiling range of having a boiling range substantially within the boiling t e S ac range of the slack wax components of the composition.

2. A process according to claim 1 wherein the waxy petroleum oil stock is a residual oil containing microcrystalline waxes.

3'. The process of segregating a substantially oil-free parafiin wax having improved low temperature character- References Cited in the file of this patent UNITED STATES PATENTS 2,248,668 Gee July 8 1941 2,670,318 Halamka et a1. Feb. 23, 1954 2,761,814 Post Sept. 4, 1956

Claims (1)

1. THE PROCESS OF SEGREGATING A SUBSTANTIALLY OIL-FREE PETROLEUM WAX HAVING IMPROVED PROPERTIES WHICH COMPRISES THE STEPS OF SOLVENT DEWAXING A WAXY PETROLEUM OIL STOCK TO PRODUCE A SUBSTANTIALLY WAX-FREE OIL AND A SLACK WAX, SOLVENT DEOILING A PORTION OF THE SLACK WAX TO SEPARATE A SUBSTANTIALLY OIL-FREE PETROLEUM WAX FROM AN OILY SOFT WAX, COMBINING THE OILY SOFT WAX WITH 3-5 VOLUMES

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