Chemistry: natural resins or derivatives; peptides or proteins; – Natural resins or derivatives – Rosin or derivative used as starting material in process – or...
Reexamination Certificate
2000-11-15
2003-01-28
Acquah, Samuel A. (Department: 1711)
Chemistry: natural resins or derivatives; peptides or proteins;
Natural resins or derivatives
Rosin or derivative used as starting material in process, or...
C106S220000, C106S221000, C106S225000, C106S713000, C524S072000, C530S211000, C530S500000
Reexamination Certificate
active
06512090
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to asphalt emulsions and emulsifiers used in preparing asphalt emulsions.
BACKGROUND OF THE INVENTION
In the manufacture of pale wood rosin from southern pine stumpwood, crude rosin is extracted from the wood and then refined using solvent/solvent partitioning between aliphatic hydrocarbon and polar solvents. One of the by-products of this operation is a dark, high melting, largely aliphatic hydrocarbon-insoluble resin, hereinafter referred to as AHI resin. AHI resin is a thermoplastic resin that chemically is a complex mixture of high molecular weight phenolic compounds, rosin acids, neutral materials and several minor components. An AHI resin is produced as described in U.S. Pat. No. 2,221,540, which patent is incorporated herein by reference in its entirety. A preferred AHI resin is Vinsol® resin available from Hercules Incorporated, Wilmington, Delaware.
AHI resin, particularly Vinsol® resin from Hercules Incorporated, Wilmington, Del., is used in a wide variety of industrial applications including asphalt emulsions. Asphalt emulsions are used in a variety of applications such as road building, road sealing, soil stabilization, mulching, surface coating of asphalt pavements, and built-up roofs. Because the amount of wood rosin produced relative to tall oil and gum rosin is declining, the supply of AHI resin available for industrial applications is also declining. Consequently, there is a need for a material which will perform in asphalt emulsions in a manner similar to AHI resin.
U.S. Pat. No. 5,656,733 describes resinous compositions comprising lignin and polymerized rosin, and the use of such compositions as asphalt emulsifiers and air entraining agents for concrete.
SUMMARY OF THE INVENTION
This invention pertains to asphalt emulsions containing an emulsifier comprising an alkali metal or ammonium salt of solidified pyrolytic wood tar oil.
In another embodiment the invention comprises a resinous composition comprising a first component selected from the group consisting of solidified pyrolytic wood tar oil and salts thereof, and a second component selected from the group consisting of rosins and salts thereof.
In yet a third embodiment the invention pertains to a method for preparing a resinous composition comprising: combining solid ingredients comprising solidified pyrolytic wood tar oil and a rosin selected from the group consisting of natural rosin, fortified rosin, polymerized rosin, hydrogenated rosin, disproportionated rosin, modified rosin and esterified rosin; and milling the combined solid ingredients until a substantially homogeneous particulate blend is obtained.
In yet another aspect, the invention pertains to a method for preparing an asphalt emulsion comprising dissolving ingredients comprising a rosin and solidified pyrolytic wood tar oil in an aqueous solution of alkali metal or ammonium hydroxide in water to form an aqueous solution of emulsifier, mixing the aqueous solution of emulsifier with asphalt to form a mixture, and milling the mixture to form an emulsion of the asphalt.
DETAILED DESCRIPTION OF INVENTION
Solidified Pyrolytic Wood Tar Oil
The solidified wood tar oil for use in the current invention is produced by thermal destructive distillation, for example fast pyrolysis of biomass, e.g., wood. The controlled, rapid heating of the biomass material (e.g., wood) initiates depolymerization reactions in the lignin component while minimizing condensation reactions. In addition, the very short reaction times and rapid vapor quench employed in fast pyrolysis preserve the lignin polymer fragments by protecting them from prolonged exposure to high temperatures. In summary, the high intensity but very short “thermal shock” of fast pyrolysis causes the lignin component of the wood feedstock to depolymerize, yielding reactive polymer fragments in a molecular size range suitable for subsequent controlled crosslinking. Fast pyrolysis processes are described in U.S. Pat. Nos. 4,876,108; 5,792,340; 5,853,548 and 5,961,786, all of which are incorporated herein by reference in their entireties.
The rapid destructive distillation or fast pyrolysis involves the rapid heating of biomass material. Reaction temperatures of 500° to 550° C. allow maximization of the production of desired product vapors while minimizing byproduct gas and char. The product vapors are rapidly condensed and collected. This product, referred to as whole oil, bio-oil or pitch is used as a feedstock for further processing to produce solidified pyrolytic wood tar oil.
The subsequent processing of the whole oil involves the non-destructive distillation and evaporative treatment of the material. The non-destructive techniques for distillation-evaporation include wipe film evaporation, roto-evaporation, agitated film evaporation, vacuum distillation, falling film, etc. These non-destructive techniques remove or reduce the content of water, acids, odors and non-resin components by heat and/or vacuum distillation. In addition, the carefully controlled temperatures used during evaporation allow a controlled polymerization of the feedstock to occur while maintaining the reactive sites in the final product. In summary, distillation/evaporation can be controlled to product an optimized degree of crosslinking or polymerization, resulting in a solidified pyrolytic wood tar oil.
In the case of the solidified pyrolytic wood tar oil for this invention, the distillation/evaporation conditions are controlled to produce product with the following preferred property ranges: softening point (Fisher-Johns), from about 100° to about 170° C.; acid number, from about 10 to about 50; glass transition temperature (T
g
) of from about 30° to about 100° C.; weight average molecular weight (size exclusion chromatography) of from about 1,500 to about 4,500; and number average molecular weight of from about 500 to about 1,000. More preferred property ranges are: softening point, from about 140° to about 160° C.;
acid number, from about 20 to about 30; glass transition temperature (T
g
) of from about 70° to about 100° C.; weight average molecular weight (size exclusion chromatography) of from about 3,000 to about 4,000; and number average molecular weight of from about 750 to about 1,000.
Preferably, the solidified pyrolytic wood tar oil will contain from about 40% to about 60% of material of number average molecular weight less than about 1,000, and from about 20% to about 30% less than about 500.
Rosins
The rosins useful for the present invention can be any thermoplastic rosin, including unfortified rosin, fortified rosin, extended rosin, rosin esters, acid modified rosin esters, polymerized rosin, dimerized rosin, disproportionated rosin, hydrogenated rosin, hydrogenated rosin esters and mixtures and blends thereof. Preferred rosins for use in the invention are fortified rosins and polymerized rosin.
The rosin used in this invention can be any of the commercially available types of rosin, such as wood rosin, gum rosin, tall oil rosin, or mixtures of any two or more in their crude or refined state. Partially hydrogenated rosins and polymerized rosins, as well as rosins that have been treated to inhibit crystallization, such as by heat treatment or reaction with formaldehyde, can also be employed. Rosins for the invention preferably will have an acid number of at least about 100, more preferably at least about 150, and most preferably at least about 200.
Fortified rosin useful in this invention is the adduct reaction product of rosin and an acidic compound containing the
group and is derived by reacting rosin and the acidic compound at elevated temperatures of from about 150° C. to about 210° C.
The amount of acidic compound employed will be that amount which will provide fortified rosin containing from about 1% to about 16% be weight of adducted acidic compound based on the weight of the fortified rosin. Methods for preparing fortified rosin are well known to those skilled in the art. See, for example, the methods disclosed and described in U.S. Pat. Nos. 2,628,918 and 2,6
Kennedy Norman Leroy
Suchanec Richard Robert
Acquah Samuel A.
Edwards David
Hercules Incorporated
LandOfFree
Asphalt emulsion containing solidified pyrolytic wood tar oil does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Asphalt emulsion containing solidified pyrolytic wood tar oil, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Asphalt emulsion containing solidified pyrolytic wood tar oil will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3071572