BACKGROUND AND SUMMARY OF THE INVENTION As is well known, modern motor oils frequently include a variety of additives, including pour point depressants and viscosity index improvers. Pour point depressants are used to reduce the temperature at which the motor oil becomes solid and is therefore no longer pourable.

Viscosity index improvers broaden the temperature range over which the viscosity of the motor oil remains relatively stable.

The assignee of the present application is the exclusive licensee of co-pending application Serial Number 09/250,741 filed February 16,1999, and entitled METHOD OF REMOVING CONTAMINANTS FROM USED OIL. In accordance with the method of the co-pending application, used motor oil is processed and is thereafter distilled at high temperature and low pressure. This results in the separation of the processed used motor oil into light base oil, medium base oil, heavy base oil, and still bottoms.

The still bottoms contain the additives, particularly including the pour point depressants and the viscosity index improvers, that were present in the motor oil at the time it was originally sold and used.

It is also well known that asphalt is a residual product generated in the process of refining crude oil.

Asphalt is used literally worldwide in a variety of applications, including road paving materials, roof coatings and shingles, and industrial coatings. For example, when asphalt is mixed with aggregates, such as sand and/or gravel, the resulting mixture forms an ideal road paving material. In fact, over 35,000,000 tons of asphalt are used annually in the construction and repair of roads and highways in the United States alone.

The quality of asphalt is defined in terms of temperature range, that is, the range of temperatures over which the asphalt is neither too soft nor too brittle to perform successfully for the intended purpose.

Unfortunately, most straight run asphalts are of relatively poor quality. It has therefore become common practice to use asphalt modifiers such as synthetic rubbers and other chemicals, to improve asphalt quality. Although generally successful in raising the high end of the temperature range at which asphalt is useful, presently available asphalt modifiers also raise the low end of the temperature range, thereby causing the asphalt to become brittle at unacceptably high temperatures.

In accordance with the present invention it has been found that the still bottoms resulting from the practice of the above-identified co-pending application comprise an

asphalt modifier which is vastly superior to any currently available asphalt modifier in improving the quality of straight run asphalt by expanding the temperature range thereof both upwardly and downwardly. The asphalt modifier of the present invention can be used singlely, that is, without the addition of other materials. The asphalt modifier of the present invention can also be used as a solubilizer or compatibilizer to facilitate the use of other asphalt modifiers.

The present invention further comprises a method of manufacturing asphalt modifiers. In accordance with one embodiment of the method, used motor oil is processed in accordance with the method of the above-identified co- pending application during which the processed used motor oil is distilled at high temperature and low pressure to provide light base oil, medium base oil, heavy base oil, and still bottoms, with the still bottoms comprising the improved asphalt modifier of the present invention.

Preferably, the composition of the still bottoms, which includes the additives from the used oil, is supplemented by the addition of chemical agents selected from the group including: 1. Polymethacrylates; 2. Ethylene-Propylene copolymers;

3. Styrene-Diene copolymers; 4. Styrene-Ester copolymers; 5. Wax Alkylated Naphthalene; 6. Cross Linked Wax Alkylated Phenols; and/or 7. Vinyl Acetate/Fumaric Acid Ester Copolymers.

In accordance with a second embodiment of the method, petroleum products not having additives contained therein are distilled at high temperature and low pressure to provide various distillates and still bottoms. Chemical agents of the types and kinds which are utilized as additives in virgin motor oils are then added to the still bottoms to provide the asphalt modifier of the present invention.

Asphalt modifiers made in accordance with any of the foregoing embodiments can be used singlely, that is, without adding further materials. Alternatively, any of the foregoing embodiments can be used as a solubilizing agent or compatibilizer for other asphalt modifiers, such as ground or pulverized latex rubber.

DETAILED DESCRIPTION In accordance with the first embodiment of the invention, virgin motor oil is provided with one or more additives, including but not limited to, one or more pour point depressants and one or more viscosity index improvers. The virgin motor oil having the additives contained therein is utilized as a lubricant in automobile engines and similar applications. Following a predetermining period of operation of the engine or other apparatus in which the motor oil is used, the now-used motor oil is recovered.

The used motor oil still having the pour point depressant and viscosity index improver additives contained therein is accumulated, in some instances from a variety of sources. The used motor oil is then processed in accordance with the method of co-pending application Serial Number 09/250,741 filed February 16,1999, which is incorporated herein by reference. At the conclusion of the process of the co-pending application, the processed used motor oil is distilled under conditions of high temperature and low pressure. Preferably, the distillation takes place at a temperature of between about 325°C and about 375°C, and at a pressure of between about. 05mm and about. 001mm.

The distillation process yields one or more relatively low

viscosity products, and results in a high viscosity product known as still bottoms which contain the pour point depressant and viscosity index improver additives of the virgin motor oil.

The still bottoms resulting from the method of the co- pending application are then employed as an asphalt modifier. The asphalt modifier of the present invention is added to straight run asphalt at levels of between about . 5% and about 5% depending upon the requirements of particular applications of the invention. In the actual practice it has been determined that the use of the asphalt modifier of the present invention is significantly superior to currently available asphalt modifiers in improving the performance of straight run asphalt. For example, the United States Department of Transportation established a program, known as the Strategic Highway Research Program, which in turn created a program known as Superpave.

Superpave was designed to develop better and longer lasting asphalt pavements. One of the primary aspects of Superpave was the establishment of a series of analysis procedures, by which asphalt binders could be objectively tested to predict the performance of the binder as a road pavement ingredient. Using the Superpave test procedures the

asphalt modifier of the present invention has been shown to improve the performance qualities of asphalt binders.

Asphalt modifiers produced in accordance with the method of the first embodiment of the invention may be utilized singlely, that is, without incorporation of other materials. Asphalt modifiers produced in accordance with the first embodiment of the invention can also be used as solubilizers or compatibilizers for other asphalt modifiers. For example, the pulverized latex materials which are currently used as asphalt modifiers are sometimes insoluble in asphalt. However, when first combined with the asphalt modifier of the present invention and then combined with straight run asphalt, pulverized latex and other currently used asphalt modifiers are thoroughly dissolved in the straight run asphalt and do not separate therefrom during use.

In accordance with a variation of the first embodiment of the invention, the still bottoms resulting from the practice of the method of the above-identified co-pending application are enhanced by the incorporation of additional chemical agents therein. For example, one or more chemical agents selected from the group including: 1. Polymethacrylates; 2. Ethylene-Propylene copolymers;

3. Styrene-Diene copolymers; 4. Styrene-Ester copolymers; 5. Wax Alkylated Naphthalene; 6. Cross Linked Wax Alkylated Phenols; and/or 7. Vinyl Acetate/Fumaric Acid Ester Copolymers may be added to the. still bottoms prior to utilization thereof as an asphalt modifier. Other variations in the practice of the first embodiment of the invention will readily suggest themselves to those skilled in the art.

In accordance with the second embodiment of the invention, one or more petroleum products not having motor oil additives contained therein are distilled in conditions of high temperature and low pressure. The distillation process is preferably carried out at a temperature of between about 325°C and about 375°C, and at a pressure of about. 05mm and about. 001mm. The distillation process separates the petroleum product or products into at least one component having relatively low viscosity and still bottoms having relatively high viscosity.

In accordance with a variation of the second embodiment of the invention, the still bottoms resulting from the distillation process are enhanced by the addition of pour point depressants and/or viscosity index improvers thereto. The pour point depressants and/or viscosity index

improvers which are utilized in the enhancement of the still bottoms comprise the same materials which are presently utilized as motor oil additives, including: 1. Polymethacrylates; 2. Ethylene-Propylene copolymers; 3. Styrene-Diene copolymers; 4. Styrene-Ester copolymers; 5. Wax Alkylated Naphthalene; 6. Cross Linked Wax Alkylated Phenols; and/or 7. Vinyl Acetate/Fumaric Acid Ester Copolymers.

Such materials are added to the still bottoms in percentages which are within the ranges at which the additives are added to virgin motor oils.

Regardless of which of the foregoing variations are employed, the enhanced still bottoms are then utilized as an asphalt modifier. Preferably, the enhanced still bottoms are added to straight run asphalt in percentages of between about. 5% and 5% depending on the requirements of particular applications of the invention. The improvements in the quality of straight run asphalt deriving from use of the asphalt modifier prepared in accordance with the process of the second embodiment of the invention are comparable with those achieved in the use of

the asphalt modifier prepared in accordance with the first embodiment of the invention.

The asphalt modifier of the second embodiment of the invention may be used singlely, that is, without the addition of other chemical agents thereto. The asphalt modifier of the second embodiment of the invention may also be utilized as a solubilizer or compatibilizer for currently used asphalt modifiers. For example, when the asphalt modifier of the second invention is used as..a. solubilizer or compatibilizer for pulverized latex materials of the type currently used as asphalt modifiers, such materials are fully dissolved in the straight run asphalt and do not separate therefrom during use.

Although preferred embodiments of the invention have been described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions of parts and elements without departing from the spirit of the invention.