TREATMENT OF PARTICULATE SURFACES

Abstract: Methods and compositions for modifying recreational surfaces are disclosed. The method includes the step of combining a particulate surface material with a sprayable composition in an amount sufficient to bind the surface material. The composition comprises a synthetic polymer material dispersed or dissolved in a fluid oil component. The polymer material is selected from natural and synthetic rubbers, olefins, copolymers of olefins, polyolefins, copolymers of polyolefins, mixtures of olefins and polyolefins, and mixtures of one or more of these. The oil component may be petroleum based. The composition may be blended in-situ with the particulate surface material.

Description: TREATMENT OF PARTICULATE SURFACES The present invention relates to compositions and methods for modifying recreational surfaces, and more particularly to compositions and methods for modifying the characteristics of particulate recreational surfaces for human beings and/or animals such as training tracks, race tracks, golf course bunkers and so on. BACKGROUND OF INVENTION Substitute ground surface materials have been proposed and are generally known. These include a mixture of raw granulated plastics material with a bitumen emulsion and water described in Australian Patent Application No. 57764/86 to DENE-HUNT LTD, and U.S. Patent No. 3,708,319 to NIMERICK, which discloses the application of a drying oil optionally containing one or more particulated water-swellable polymers to the surface of fine particulate material to prevent the material from being blown about by wind or washed along by water. In addition, Australian Patent No. 625755 (30589/89) in the name of AYTON ASPHALTE LTD and NOONAWEENA LTD discloses a composition for mixture with a particular material such as sand to form the top layer of an exercise area, the composition comprising a resilient granular filler coated with an oil component. Another proposal for a material for use as a substitute soil material is that disclosed in Australian Patent Application No. 67541/87 in the name of EN-TOUT-CAS pic, which comprises sand or other particulate or granulate mineral material treated with a binder of synthetic polymer material in an oil, the oil being substantially non-fluid at ambient temperatures so as to produce an inert, discrete material permanently capable of being raked. The substitute soil material is said to provide a suitable surface for the training of horses. The most notable commercial embodiment of the above disclosures is that of the aforementioned EN-TOUT-CAS material, presently marketed under the trade mark EQUΓTRACK. The EN-TOUT-CAS composition however suffers from a number of shortcomings. These include the need for extensive pre-preparation to mix the particulate material with the binder prior to laying it on a surface. In addition, the EN-TOUT-CAS composition, being formed from ethyl vinyl acetate, has a tendency to form solid clods of earth which can create a hazard for horses when the earth is kicked up during running. Furthermore, the EN-TOUT-CAS composition tends to become very hard in wet or cold conditions, and very sticky in hot, dry conditions, leading to an inconsistency in the properties of the treated ground surface. In addition, it has been found that over a relatively short period (eg. 5 years), EQUITRACK treated surfaces tend to solidify and require replacement. This treatment is accordingly now considered to have a limited life span. There is therefore a need for a method of treating a recreational surface, composition which is capable of being applied in-situ to a recreational surface, to provide a treated surface whose properties will not vary unduly in varying weather conditions. There is also a need for a composition which will provide a substantially stable recreational surface during varying load conditions. SUMMARY OF INVENTION Accordingly, the present invention provides, in one embodiment, a method for treating a particulate recreational surface, the method including the step of combining the particulate surface material with a sprayable composition in an amount sufficient to bind the surface material, the composition comprising a synthetic polymer material selected from natural and synthetic rubbers, olefins, copolymers of olefins, polyolefins, copolymers of polyolefins, mixtures of olefins and polyolefins, and mixtures of one or more of the foregoing dispersed or dissolved in a fluid oil component whereby to form a treated particulate surface. In another embodiment, the present invention provides a composition for treating a particulate recreational surface, the composition comprising a synthetic polymer material selected from natural and synthetic rubbers, olefins, copolymers of olefins, polyolefins, copolymers of polyolefins, mixtures of olefins and polyolefins, and mixtures of one or more of the foregoing dispersed or dissolved in a fluid oil component. The oil component preferably has a viscosity selected so as to be substantially fluid at ambient temperatures. The composition is preferably capable of being combined in-situ with a particulate recreational surface. It has been surprisingly found that, in contrast to particulate surface treatments of the prior art, particulate surfaces treated with compositions according to the present invention do not tend to form hard agglomerates, or do not tend to form such agglomerates to any significant extent. This enables the treated surface and any agglomerates formed therein to break down readily when a shear force is applied to the surface, such as for example a horse's hoof landing on the surface. As noted above, polymer materials for use in compositions according to the present invention may include natural and synthetic rubbers, olefins, copolymers of olefins, polyolefins, copolymers of polyolefins, and mixtures of olefins and polyolefins. More specific examples include dienes, polyisobutylene, copolymers of ethylene/propylene, copolymers of styrene/butadiene, and copolymers of styrene/butylene. The polymer material is preferably selected so as to be water-imbibing to varying degrees depending on environmental conditions. The molecular weight of the polymer material is preferably reasonably high. A suitable molecular weight of a polymer material for compositions according to the present invention is at least about 20,000 and preferably in the range of about 70,000 to about 400,000. The proportion of synthetic polymer to oil component may vary within the above molecular weight ranges depending on the desired characteristics of the composition. These include dryness, stickiness, permeability and so on. At a selected constant molecular weight, a minor proportion of polymer may be combined with a major proportion of a heavy oil component, to yield a sticky composition. Alternatively, at approximately the same selected constant molecular weight, a major proportion of polymer may be combined with a minor proportion of light oil, to yield a dry composition. Still further, a low molecular weight polymer combined with an oil component of high viscosity is likely to yield a composition which is relatively permeable. Other variation ' s in molecular weight and proportions of components are envisaged as being within the scope of the present invention. The polymer material may be present in the composition in any suitable amount by weight. Preferably, the polymer material is present in amounts in the range of about 1 to about 20% by weight, and most preferably about 3 to about 6% by weight. In one embodiment according to the present invention the polymer material employed in compositions according to the present invention preferably comprises a copolymer of ethylene and propylene. It is presently preferred that the ethylene/propylene copolymer contains about 50% ethylene by weight. A presently preferred copolymer material of ethylene and propylene is VISTALON 404 (trade mark) produced by Exxon Corporation, which is a solid copolymer of ethylene and propylene. The oil component of a composition according to the present invention preferably has a viscosity selected such that the oil is substantially fluid at ambient temperatures. The viscosity of the oil component may be in the range of up to about 2500 centistokes and preferably about 10 to about 1000 centistokes at 40 °C. The oil component may be selected from organic oils, petroleum based oils, bitumen or gas oil, siliconised oils, molasses, latexes, and alginates. The oils preferably contain low aromatics, and in the case of petroleum based oils are preferably predominantly paraffinic. The oil component may be present in the composition in any suitable amount. Preferably, the oil component is present in the composition in amounts in the range of about 80 to about 99% by volume, and most preferably about 94 to about 97% by volume. The composition provided in accordance with the present invention may also contain one or more U.V. stabilisers to reduce the effect of ultraviolet light on the treated particulate surface. Whilst not considered essential to the invention, the addition of U.V. stabilisers assists in maintaining the composition fluid longer. It has also been found in one preferred embodiment that the use of a U.V. stabiliser comprising a thiodipropionic acid surprisingly produces a synergistic U.V. stabilisation and antioxidation effect. One such suitable stabiliser is IRGANOX (a trade mark of Ciba-Geigy), which is a dialkyl ester of thiopropionic acid. Another suitable U.V. stabiliser comprises benzophenone. One or more antioxidants to stabilise the composition, may also be added to compositions according to the present invention. Any antioxidant present in the composition may be present in amounts in the range of about 0.5 to about 3% and preferably about 1 to about 2% by weight of the composition. One example of suitable antioxidants are those based on phenol, such as a phenol-based IRGANOX. For aesthetic purposes, one or more pigments may be added to the composition. Any pigments as are generally presently known in the art are suitable for addition to compositions of the present invention. Pigments may be added to compositions according to the present invention as required during blending of the synthetic polymer and oil components. A composition according to the invention may be blended with one or more particulate materials such as sand, soil, clay, sawdust, wood fibre, plastics, which may or may not comprise fillers and/or re-enforcing fibres of plastics, waxes, rubber, cork, wool, shredded carpet or like materials. Blending may occur either in-situ or prior to laying on a particulate surface. The polymer material may be added to the oil component in particulate form to facilitate dispersion. In the case of a solid polymer, the polymer is preferably cut into pieces to promote dispersion or dissolution in the oil. A composition according to the invention may be further characterised by reference to its viscosity. Preferably the viscosity of the composition is at least about 300 centistokes, and more preferably will range from about 300 centistokes to about 8000 centistokes. For some applications, such as the floor of golf course bunkers, the viscosity more preferably ranges from about 600 to about 1000 centistokes, while for such uses as race tracks the viscosity more preferably ranges from about 1500 to about 3500. Compositions according to the present invention have generally been observed to possess a tackiness quality whilst being both cohesive and adhesive. One presently preferred composition according to the present invention comprises the following: mineral oil about 2175 parts by weight synthetic rubber about 59 parts by weight antioxidant (phenol-based Irganox) about 50 parts by weight stabilizer (thiodipropionic acid-based Irganox) about 21 parts by weight The particulate surface material is preferably selected from materials which will not tend to agglomerate so as to form substantially solid clods, or will not tend to so agglomerate to any significant extent when combined with compositions according to the present invention. One suitable surface material consists of or includes sand. Particle sizes up to about 6mm in diameter have been found to be particularly suitable for the practice of the present invention. It has been observed that the more similar the particle size, the less compaction is likely to occur, whilst the more variable the particle size, the greater the compaction obtainable. A composition according to the present invention may be combined with the particulate surface material either in-situ, or in a pre-preparation step by mixing the composition with the particulate surface material. We presently prefer to spray the composition directly onto a particulate surface to be treated. However, pre-treatment of the particulate surface material and subsequent laying of the particulate surface material onto a suitable surface is also envisaged as being within the scope of the present invention. For in-situ application of a composition according to the present invention, the composition is preferably blended with the particulate surface to be treated, such as by mechanical methods, including harrowing and/or raking to the desired depth. The composition is preferably applied to the particulate surface material in an amount which is sufficient to bind the surface material. The amount of composition applied to a surface varies with the type and composition of the particulate it is blended with, and the desired result. Whilst it is not generally intended for the composition according to the present invention to constitute the entire binder surface, it can perform such a function. It is generally intended that a composition according to the invention complements or improves the binding of a surface that is already bound or compacted by normal standards. Put another way, it is preferred that the composition of the present invention improves the natural binding of the surface achieved by materials constituting the surface, namely clays, compost and a variety of particulate sizes. Accordingly, whilst the composition of the present invention can be blended with a particulate surface material prior to laying it on a suitable surface, it has been found to be more convenient to spread the composition of the invention directly on to the already laid particulate surface and blend it in-situ. The particles of the particulate surface material are preferably coated with a composition according to the present invention. The particulate material is preferably selected so as to have limited air entrainment, thus producing a soft cushioned feel to the surface of the ground. As noted above, a composition according to the present invention may be combined with the particulate surface material to be treated by in-situ treatment, such as by spraying or other application. In one particularly preferred embodiment for particulate surfaces such as training tracks, it has been found that application rates in the range of about 0.2 to about 5 litres of the composition per square metre of particulate surface, followed by in-situ blending by harrowing or raking to a depth of approximately 75 mm generally achieve the desired characteristics of the treated surface. Preferably the composition is initially applied at a rate in the range of about 1 to about 2 litres per square metre, and more preferably approximately 1.5 litres per square metre of surface to be treated. Subsequent applications in the range of about 0.2 to about 1 litre per square metre per year blended by harrowing or raking to a depth of approximately 75 mm have been found to be adequate to maintain the surface in the desired condition. For other applications eg. golf course bunkers, these application rates may generally be at the lower end of the application rates noted. One preferred method of treating a particulate surface material according to the present invention comprises contacting the surface to be treated with a composition according to the invention, preferably by spraying, and harrowing or raking the surface to the desired depth. It is preferred if the surface is allowed to settle/consolidate to the desired firmness before use or rainfall occurs. The surface may be consolidated by compaction, rolling or other known methods. Advantageously, the composition is applied to the surface to be treated without the application of heat. However, if accelerated blend times are required, the composition may be heated. Compositions according to the invention have been found to impart to the surface the ability to retain a greater amount of air which assists in producing a cushioned or springy feel about the surface. This springiness can be further improved by the addition of fibres or particulates of other substances such as cork, rubber, shredded carpet, polymers and so on. In the case of a person, animal or object changing direction, a particulate surface treated according to the present invention has been found to conform to the weight and shape of the object pressing on it, to form a firm full bank of surface at the angle in which the movement is going. This has been found to result in a reduced likelihood of slipping on the surface. BRIEF DESCRIPTION OF PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in relation to the following non-limiting example relating to the treatment of a horse training surface. It will be readily appreciated that compositions according to the present invention are not in any way limited to the treatment of surfaces for horses, but include other particulate surfaces such as golf course bunkers and so on. EXAMPLE 1 An ethylene/propylene copolymer containing about 50% ethylene was placed in a blender with a petroleum oil component having a viscosity of about 100 centistokes at about 40° C at a ratio of about 1 part copolymer to about 1 part oil component by weight. The composition was heated to about 170°C while it was dissolved by stirring. The resultant composition was found to have a kinematic viscosity of 2600 centistokes. The composition was then sprayed through a perforated plastic three metre tube (similar equipment to a water laying truck) onto an existing dry particulate sand surface at an application rate of one litre per square metre, and thoroughly blended by harrowing down to a depth of 75 mm. The surface was then compacted by rolling (tamping can also be used in some situations) to a race ready state. The thus-treated surface was found to exhibit a considerable degree of spring cushioning, aeration and resilience, whereby a horse's hoof did not sink into the sand to the same degree as would be expected with untreated sand. The hoof was also found to have a much firmer takeoff point than it would normally have on other surfaces, thus allowing the animal to move across the surface with less effort. In addition, it was observed that, whilst the treated particulate sand surface was firm, it did not pack so hard as to form hard agglomerates or clods when thrown up by the hooves, but instead separated into a fine granular spray. The edges of the divots were soft and easily conformed to a flat surface again when the next hoof landed on that area, instead of being hard as with existing surfaces and causing stress to the leg joints by making them roll on the uneven surface. There was found to be no dust generation whatsoever, and droppings were found to be easily removed. On-going maintenance of a particulate surface treated in accordance with the present invention has been found to be straightforward in that it only requires very light watering (during dry periods), harrowing and rolling so as to tune it to the desired firmness or fluffiness. In addition, by having a reasonable camber of 10 to 40 degrees of flat rolled surface, the surface will become substantially water proof, as the water will drain off the slope. During trials a composition according to the foregoing description experienced heavy rain at regular intervals over a 30 day period without loss of track surface or leaching of the product down into the substrate. Should rain seep into the surface substrate and is unable to drain away, it has been found that firm rolling will expel the water. EXAMPLE 2 In this Example, the polymer content of the composition of Example 1 was reduced by half. The viscosity of the resulting composition was approximately 770 centistokes. The composition was applied to a particulate surface at a rate of approximately 1 litre per square metre, and was found to have particularly desirable results for sections of golf courses bunkers, reducing water and wind erosion and binding the particulate surface. EXAMPLE 3 In this Example, the polymer content of the composition of Example 1 was increased to 300 parts by weight and the molecular weight and the viscosity of the oil component markedly reduced compared to that of example 1, to obtain a particulate surface having the desired characteristics at an application rate of approximately 2 litres per square metre. A particulate surface treated with this composition exhibited characteristics similar to those of a particulate surface treated with the composition of Example 1. EXAMPLE 4 In this Example, a blend of 75 parts by weight polyisobutylene and 25 parts by weight of an ethylene/propylene copolymer with a light oil and 50 parts by weight antioxidant was prepared and applied to a particulate surface at a rate of approximately 1.5 litres per square metre to a depth of 75mm, to achieve a treated surface having the desired characteristics. A particulate surface treated with this composition exhibited similar characteristics to a particulate surface treated with the composition of Example 1. EXAMPLE 5 In this Example, a blend of 184 parts by weight of a styrene/butadiene copolymer having 95% styrene and 92 parts by weight of an ethylene/propylene copolymer having 50% propylene with a light mineral oil and 1.5% by weight antioxidant/U.V. stabiliser was prepared. The resulting composition was applied to a dusty particulate surface at an application rate of approximately 4 litres per square metre. It was noted that the particulate surface absorbed a considerable amount of the composition. A particulate surface treated with this composition exhibited similar characteristics to a surface treated with the composition of Example 1, with the exception that it was drier. It was observed from the foregoing Examples that the higher polymer content of the compositions of Examples 3 and 5 generally produced a drier composition and hence a drier treated particulate surface. Compositions according to the present invention have been found to assist in stabilising the treated surface, usually but not always a particulate surface, and also serves to prevent dust generation and surface erosion. It also provides a surface cushioning effect. It has also been found that a surface treated with a composition according to the present invention, unlike compositions of the prior art, does not generally form a solid clod but enables the treated surface to re-break. The combination of the synthetic polymer material and oil component has been found to impart a considerable degree of firmness to the treated surface so that displacement of the surface is limited on impact. This causes buoyancy in the surface or less sinking in the surface, and a greatly improved pad for moving off. Whilst the foregoing description has been principally directed to training or race tracks for horses, it is to be noted that compositions according to the present invention are suitable for treating many other surfaces, including any surface which requires a degree of stabilisation to counter prevailing weather conditions such as wind or rain, heavy traffic areas, golf course bunkers and so on. SUBSTTTUTE SHEET (Rule 26) While it has been convenient to describe the invention herein in relation to particularly preferred embodiments, it is to be appreciated that other constructions and arrangement are also considered as falling within the scope of the invention. There is modifications, alterations, variations and/or additions to the constructions and arrangements described herein are also considered as falling within the scope and ambit of the present invention. SUBSTrrUTE SHEET (Rule 26)

Claims: CLAIMS 1. A method for treating a particulate recreational surface, the method including the step of combining the particulate surface material with a sprayable composition in an amount sufficient to bind the surface material, said composition comprising a synthetic polymer material selected from natural and synthetic rubbers, olefins, copolymers of olefins, polyolefins, copolymers of polyolefins, mixtures of olefins and polyolefins, and mixtures of one or more of the foregoing dispersed or dissolved in a fluid oil component, whereby to form a treated particulate surface. 2. A method according to claim 1, wherein said polymer material is selected from dienes, polyisobutylene, copolymers of ethylene and propylene, copolymers of styrene and butadiene, copolymers of styrene and butylene, and mixtures of one or more of the foregoing. 3. A method according to claim 2, wherein said polymer material comprises a copolymer of ethylene and propylene. 4. A method according to claim 1, wherein the molecular weight of the polymer material is at least about 20,000. 5. A method according to claim 1, wherein the viscosity of the composition is at least about 300 centistokes. 6. A method according to claim 1, wherein the polymer material is present in said composition in an amount in the range of 1 to 20% by weight. 7. A method according to claim 1, wherein said fluid oil component is a petroleum based oil. 8. A method according to claim 1, wherein the fluid oil component is present in the composition in an amount in the range of 80 to 99% by volume. 9. A method according to claim 8, wherein the viscosity of the fluid oil component is at least about 2500 centistokes at 40°C. 10. A method according to claim 1, wherein said composition contains one or more U.V. stabilisers. 11. A method according to claim 1, wherein said composition contains one or more antioxidants. 12. A method according to claim 1, where.r said compo. c in contains one or more pigments. 13. A method according to claim 1, wherein said composition is combined with the particulate surface at a rate in the range of about 0.2 to 5 litres per square metre of particulate surface. SUBSTΠT TE SHEET (Rule 26) 14. A method according to claim 1, wherein the composition is blended in-situ with the particulate surface material. 15. A method according to claim 14, wherein said blending includes harrowing and/or raking the treated surface to the desired depth. 16. A method according to claim 15 and further including the step of consolidating the treated surface by rolling and/or tamping. 17. A method for treating a particulate recreational surface, the method including the steps of spraying the particulate surface material with a sprayable composition in an amount sufficient to bind the surface material, said composition comprising a copolymer of ethylene and propylene dispersed or dissolved in a fluid petroleum based oil component, harrowing and/or raking the surface material to the desired depth and consolidating the surface material by rolling and/or tamping, whereby to form a treated particulate surface. 18. A recreational surface treated according to the method of claim 17, wherein said recreational surface is on a golf course or a track, such as a track for race horses. 19. A sprayable particulate surface treatment composition comprising a synthetic polymer material dispersed or dissolved in a fluid oil component, wherein said polymer material is selected from natural and synthetic rubbers, olefins, copolymers of olefins, polyolefins, copolymers of polyolefins, mixtures of olefins and polyolefins, and mixtures of one or more of the foregoing. 20. A composition according to claim 19, wherein said polymer material is selected from dienes, polyisobutylene, copolymers of ethylene and propylene, copolymers of styrene and butadiene, copolymers of styrene and butylene, and mixtures of one or more of the foregoing. 21. A composition according to claim 20, wherein said polymer material comprises a copolymer of ethylene and propylene. 22. A composition according to claim 19, wherein the molecular weight of the polymer material is at least about 20,000. 23. A composition according to claim 19 having a viscosity of at least about 300 centistokes. 24. A composition according to claim 19, wherein the polymer material is present in said composition in an amount in the range of 1 to 20% by weight. 25. A composition according to claim 19, wherein the fluid oil component is present in the composition in an amount in the range of about 80 to 99% by volume. 26. A composition according to claim 19, wherein said fluid oil component is petroleum based. 27. A composition according to claim 19, wherein the viscosity of the fluid oil component is at least about 2500 centistokes at 40°C. SIΓBSTΓΓUTE SHEET (Rule 26) 28. A composition according to claim 19, and further including one or more U.V. stabilisers. 29. A composition according to claim 19, and further including one or more antioxidants. 30. A composition according to claim 19, and further including one or more pigments. 31. A drum of material containing a polymer material selected from natural and synthetic rubbers, olefins, copolymers of olefins, polyolefins, copolymers of polyolefins, mixtures of olefins and polyolefins, and mixtures of one or more of the foregoing dispersed in a fluid oil component, for treating a particulate surface material.

Inventors: CRAWFORD ROBERT MURRAY, CRAWFORD, ROBERT, MURRAY
Applicants: BACLOW GARDENS PTY LTD, CRAWFORD ROBERT MURRAY, CRAWFORD, ROBERT, MURRAY
Application year: 1995
Main classification: C09D107
IPC codes: A63C19, B05D7, C09D121, C09D123, E01C13