Patent Application
20080073849
The projectable targets of the invention are made from a composition comprising a filler material and a binder for the filler material as described below.
Filler Material
The composition can include any suitable filler material or combinations of different filler materials. Some examples include clay, calcium carbonate (limestone), other ground rocks such as mica powder, asbestos powder or pumice powder, metal powders, in particular metal sulfates or sulfites, non-metallic sulfates or sulfites, metal oxides, talc, silicates such as sand, gypsum, fly ash, glass powder, magnesium carbonate, and titanium oxide. The filler may be in any suitable form, such as powdered or granulated.
The filler material can be included in any suitable amount in the composition. In one embodiment, the composition includes from about 20 wt % to about 65 wt % filler material and from about 35 wt % to about 80 wt % binder.
Binder
The binder for use in the composition is a mixture of asphalt and an asphalt modifier selected from polymers, waxes, asphaltites, and combinations thereof. In one embodiment, the asphalt modifier is a combination of polymer and wax. In another embodiment, the asphalt modifier is wax or asphaltite. In a further embodiment, the binder is substantially free of pitch.
The binder has physical properties that in combination with the filler allow the production of a projectable target having desirable properties. For example, these properties may include the hardness (penetration), softening point and viscosity of the binder. In one embodiment, the binder has physical properties including at least one of a penetration within a range of from 0 dmm to about 5 dmm at 25° C., a softening point within a range of from about 80° C. to about 175° C., and a viscosity within a range of from about 1,000 centipoise to about 25,000 centipoise at 163° C. In another embodiment, the penetration, viscosity and softening point of the binder are all within the defined ranges.
In a particular example, the penetration of the binder is within a range of from 0 dmm to about 3 dmm at 25° C., or more particularly from 0 dmm to about 1 dmm at 25° C. The penetration can be measured by any suitable method, such as ASTM D-5.
In another example, the softening point of the binder is within a range of from about 90° C. to about 150° C., or more particularly from about 100° C. to about 120° C. The softening point of the binder can be measured by any suitable method, such as the ring and ball method, ASTM D-36
In a further example, the viscosity of the binder is within a range of from about 1,500 centipoise to about 10,000 centipoise at 163° C., or more particularly from about 2,000 centipoise to about 5,000 centipoise at 163° C. The viscosity of the binder can be measured by any suitable method, such as ASTM D4402.
Asphalt
The asphalt can be a naturally occurring asphalt or a manufactured asphalt, for example, a petroleum-derived asphalt produced by a petroleum refining operation. Any type of asphalt can be used, such as a straight run asphalt, an oxidized asphalt, or an asphalt cement.
In some embodiments, the asphalt is a relatively hard asphalt, e.g., an asphalt having a penetration of not greater than about 15 dmm at 25° C., not greater than about 5 dmm, not greater than about 2 dmm, or about 0 dmm depending on the particular embodiment. The penetration can be measured by any suitable method, such as ASTM D-5. A hardened asphalt can be obtained by oxidizing the asphalt and/or by the selection of the starting asphalt.
The oxidizing process comprises blowing air, oxygen or an oxygen-inert gas mixture through the asphalt at an elevated temperature for a time sufficient to increase the softening point and thereby harden the asphalt to the desired properties. In some embodiments, the oxidized asphalt has a softening point of at least about 100° C., at least about 120° C., at least about 140° C., or at least about 150° C. depending on the particular embodiment. The softening point of the asphalt can be measured by any suitable method, such as the ring and ball method, ASTM D-36.
In some embodiments, the asphalt is a solvent extracted asphalt. Solvent extraction techniques are well-known in the art and typically employ the use of a C3-C5 alkane, usually propane. These techniques are variously referred to in the art as deasphalting or as producing a propane deasphalted asphalt (PDA), a propane washed asphalt (PWA), or a propane extracted asphalt (PEA). Typically such techniques involve treating normal crude oil and/or vacuum residue feedstock with such alkanes whereby a treated asphalt is obtained in which the percentages of asphaltenes and resins are increased. Any suitable solvent extracted asphalt can be used in the invention. Exemplary of the solvent extracted asphalts are PDA's sold by Alon USA Energy, Inc., Dallas, Tex., by Cenex Asphalt, Laurel, Mont., and by Murphy Refining, Meraux, La.
Polymer
The asphalt modifier in the binder can include any suitable polymer, or a combination of different polymers. For example, a wide variety of different thermoplastic polymers known in the art may be suitable for use in the binder.
In some embodiments, the polymer is a hydrocarbon resin. The hydrocarbon resins are low molecular weight thermoplastic polymers synthesized via the thermal or catalytic polymerization of cracked petroleum distillates, coal-tar fractions, terpenes, or pure olefinic monomers. The hydrocarbon resins include aliphatic, aromatic and alicyclic resins.
Some examples of hydrocarbon resins include the LX® series of petroleum hydrocarbon resins sold by Neville Chemical Co., Pittsburgh, Pa. These hydrocarbon resins are mixed aromatic/alicyclic in content. For example, LX®-1035 has a softening point of about 170° C., an iodine number (Wijs) of about 170, a molecular weight (GPC) of about 605, and a viscosity (Gardner) at 25° C. of about 35 (70% in toluene).
Other examples of hydrocarbon resins include the modified hydrocarbon resins sold by Neville Chemical Co. These are aromatic hydrocarbon resins. For example, AG-12-28 has a softening point of about 150° C., an iodine number (Wijs) of about 145, a molecular weight (GPC) of about 710, and a viscosity (Gardner) at 25° C. of about 52 (70% in toluene).
In some embodiments, the polymer used in the binder has a relatively high softening point. For example, the softening point may be greater than about 100° C., greater than about 120° C., or within a range of from about 120° C. to about 180° C. depending on the particular embodiment.
Wax
The asphalt modifier in the binder can include any suitable wax, or a combination of different waxes. Some examples include synthetic waxes, petroleum waxes such as microcrystalline waxes and paraffin waxes, and polyolefin waxes such as polyethylene waxes.
For example, Fischer-Tropsch waxes are examples of suitable synthetic waxes. The Fischer-Tropsch waxes are polymethylenes made by polymerizing carbon monoxide in the presence of hydrogen, using high pressure and unique catalysts. Any suitable Fischer-Tropsch wax can be used, for example, a BARECO® PX-105 Polymer sold by Baker Petrolite Corp., Sugar Land, Tex. This wax has a softening point of about 105° C., a penetration of about 1 dmm (25° C., a viscosity of about 110 SUS@ 99° C., and a white color.
Petroleum waxes consist of mixtures of paraffinic, isoparaffinic and naphthenic hydrocarbons. The physical differences between various types of petroleum wax are due to the relative extent of the three types of hydrocarbons present and the molecular weight of the hydrocarbons. Microcrystalline waxes contain higher amounts of isoparaffinic hydrocarbons and naphthenic hydrocarbons than do paraffin waxes. Typical microcrystalline wax crystal structure is small and thin, making them more flexible than paraffin wax. Any suitable microcrystalline wax can be used, for example, any of the BARECO® microcrystalline waxes sold by Baker Petrolite Corp. Low melt brands of BARECO® Wax include BE SQUARE®, STARWAX®, VICTORY® AND ULTRAFLEX® Waxes. These waxes have softening points within a range of about 66° C. to about 93° C., a penetration≧6 dmm (25° C., 30-60% normal paraffins, and a dark brown to off white color. A particular example is a BE SQUARE® 185, Amber Wax having a softening point of about 91° C. and a penetration of about 10 dmm@ 25° C.
The wax can have any suitable physical properties. In some embodiments the wax has a softening point within a range of from about 65° C. to about 120° C. and a penetration within a range of from about 1 dmm to about 15 dmm@ 25° C.
The wax can be included in any suitable amount in the binder. When the binder includes asphalt and wax, in one embodiment the binder comprises from about 60 wt % to about 95 wt % asphalt and from about 5 wt % to about 40 wt % wax. When the binder includes asphalt, polymer and wax, in one embodiment the binder comprises from about 50 wt % to about 90 wt % asphalt, from about 5 wt % to about 30 wt % polymer and from about 5 wt % to about 20 wt % wax.
Asphaltite
The asphalt modifier in the binder can include any suitable asphaltite, or a combination of different asphaltites. The asphaltites are gilsonite, grahamite and glance pitch. These are naturally occurring hydrocarbon substances characterized by a high softening point (above 110° C.). They are mined much like other minerals and sold essentially in their native state. They are fully compatible with asphalt. In some embodiments of the invention, gilsonite is used as the asphalt modifier. Gilsonite is currently sold in the form of a dry bulk solid granular powder.
The asphaltite can be included in any suitable amount in the binder. In one embodiment, the binder comprises from about 60 wt % to about 95 wt % asphalt and from about 5 wt % to about 40 wt % asphaltite.
Other Additives
In addition to the above-described materials, the composition for making the projectable targets may also optionally include one or more additives. For example, such additives may include sulfur, surfactants, release agents, set-controlling agents, antioxidants, pigments, lubricants and/or fire retardants.
Projectable Target
The projectable target may be useful for trap or skeet shooting, for competition or sport shooting, or for any other type of activity using a projectable target.
The projectable target can have any shape and size suitable for its intended use. As known in the art, clay pigeons include various shapes and sizes, including standard clay pigeons, a slightly different set of dimensions for “Olympic” targets, both of which are generally saucer-shaped, and a “running rabbit” target which has much different dimensions and shape (essentially a flat-disc). The projectable target is usually shaped so that its trajectory is stable when it is propelled, and is manufactured to a specified size and weight.
After the projectable target has been formed and hardened, the outside of the targets may optionally be coated with any suitable coating. In some embodiments, the coating is a colored coating such as a paint, finish or stain. Any suitable type of paint can be used, such as an enamel or lacquer paint.
Properties of the Projectable Target
The projectable target is strong enough to avoid breaking apart when it is launched into the air and also during normal transportation and handling. At the same time, the target has sufficient brittleness enabling it to disintegrate when hit by shotgun pellets. The brittleness can be measured by any suitable method. For example, the target may have sufficient brittleness and dimensions such that when shot at with bird shot from a twelve gauge shotgun from a distance of 25 meters by shooters skilled enough to hit about 98% of the targets from that distance, less than about 10% of targets hit by at least one pellet will remain unbroken.
Method of Manufacture
The projectable target can be manufactured by any suitable method. Some examples of manufacturing methods that may be used, depending on the particular composition, include molding, casting or pressing. Clay pigeons are often formed by mixing together the materials of the composition and then molding the mixture into the desired shape. For example, the materials may be mixed by using machines such as mixers, mixing rolls or kneaders. The materials may be mixed under heated conditions to facilitate the mixing, for example by using a mixer having a heating device. The mixed materials may then be molded using any suitable molding method, such as injection molding or compression molding. The mixed materials may be powdered, granulated or pelletized before it is fed into the molding machine. Further, the heating and blending step may be accomplished in the molding process by using an injection molding machine having a premixing-preplasticizing device such as an injection molding machine with a blend-feeder. After the projectable targets have been formed and hardened, the outside of the targets may be coated with any suitable coloring material.
A projectable target is made by molding a composition including a filler material and a binder. The binder is a mixture of asphalt, hydrocarbon resin and wax. The asphalt is a solvent extracted asphalt which is oxidized to a softening point within a range of from about 140° C. to about 180° C., and more particularly from about 140° C. to about 160° C. The asphalt has a penetration of about 0 dmm at 25° C. The hydrocarbon resin has a softening point within a range of from about 120° C. to about 175° C. The hydrocarbon resin is included in an amount within a range of from about 5% to about 40% by weight of the binder, more particularly from about 10% to about 30%. The wax is included in an amount within a range of from about 1% to about 10% by weight of the binder, more particularly about 5%.
A projectable target is made by molding a composition containing 45 wt % bentonite clay and 55 wt % binder. The binder contains 75 wt % PDA asphalt (from Alon) oxidized to a softening point of 149° C., 20 wt % hydrocarbon resin (LX-1035® from Neville), and 5 wt % Fischer-Tropsch wax (BARECO® PX-105 from Baker Petrolite).
Another projectable target is made by molding compositions containing 45 wt % bentonite clay and 55 wt % binder. The binder contains 90 wt % PDA asphalt and 10 wt % Fischer-Tropsch wax.
Another projectable targets is made by molding compositions containing 45 wt % bentonite clay and 55 wt % binder. The binder contains 90 wt % PDA asphalt and 10 wt % gilsonite.
In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiments. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.
