AU2013270530A1 - Artificial Surfaces and Methods for their Production - Google Patents

Abstract

A method for converting an existing surface to a base for a solid surface, the method comprising the steps of: applying a binder to form a bound surface, and applying a re surfacer to the bound surface.

Description

P/00/01 1 Regulation 3.2(2) AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Application No. Lodged: Invention Title: ARTIFICIAL SURFACES AND METHODS FOR THEIR PRODUCTION The following statement is a full description of this invention, including the best method of performing it known to: 2 ARTIFICIAL SURFACES AND METHODS FOR THEIR PRODUCTION FIELD OF INVENTION [0001] The present invention relates to the field of artificial surfaces, particularly artificial surfaces for sports and recreation, including artificial surfaces which can act as bases on which synthetic surfaces can be laid. [0002] In one form, the invention relates to a method of converting a synthetic grass surface to a solid artificial surface. [0003] In another form, the invention relates to a method of converting a particulate surface, such as compacted crushed rock, into a base for a solid artificial surface, or solid surface suitable for sports and recreation. [0004] In another form the invention relates to a robust base suitable for supporting installation of a solid artificial surface. [0005] In one particular aspect the present invention is suitable for converting existing synthetic grass tennis courts to solid surfaces such as hardcourt. [0006] It will be convenient to hereinafter describe the invention in relation to artificial sporting surfaces, however it should be appreciated that the present invention is not limited to that use only and can be applied to surfaces for a wide range of purposes. These include, for example, surfaces for architectural features such as vehicle parking, pathways, and so forth. [0007] Furthermore, while the present invention will be described with particular reference to artificial surfaces for tennis, it should be appreciated that the present invention is not limited to surfaces used for tennis but can be applied to surfaces for a wide range of sports.

3 BACKGROUND ART [0008] It is to be appreciated that any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the present invention. Further, the discussion throughout this specification comes about due to the realisation of the inventor and/or the identification of certain related art problems by the inventor. Moreover, any discussion of material such as documents, devices, acts or knowledge in this specification is included to explain the context of the invention in terms of the inventor's knowledge and experience and, accordingly, any such discussion should not be taken as an admission that any of the material forms part of the prior art base or the common general knowledge in the relevant art in Australia, or elsewhere, on or before the priority date of the disclosure and claims herein. [0009] There are many types of synthetic surfaces that are designed to provide the advantages of natural playing surfaces such as grass, clay, en tout cas etc in combination with the advantages of synthetic materials such as wearability and weatherability. Synthetic surfaces used for sport are broadly classified in two groups: (a) synthetic grass comprising tufted fibrous material, and (b) solid surfaces comprising a cushioned or stiff integral layer of a synthetic material, which can be further divided into (b)(i) cushioned surfaces, and (b)(ii) hard surfaces. [0010] Solid surfaces: A typical solid surface is described in Australian patent number 597484 (Rebound Ace). This patent describes a tennis court surface comprising a laminate of (1) a porous base layer formed from a matrix of liquid polyurethane mixed with resilient particles; (2) a polymeric sealant which seals the upper porous surface of the base layer; (3) a fibre reinforced adhesive layer on the upper surface of the sealant; and (4) an acrylic top coat which act as a wear layer on the upper surface of the sealant. [0011] These types of surfaces require a solid sub-base. During construction of the sub-base, bedding sand is placed over the sub-grade to level the base, permit moisture escape and allow movement of overlying layers. The bedding sand is covered with 4 construction film, then steel mesh, followed by concrete or asphalt which is kept to shape by boxing around the perimeter of the tennis court. [0012] Synthetic grass: In recent times, sand filled artificial grass (SFAG) have become popular for tennis and many natural grass, clay, en tout cas, asphalt courts and courts based on crushed, compacted road base have been replaced with synthetic grass courts. SFAG comprises a green outdoor carpet filled with sand so that only the tips of the tufts protrude, giving the appearance of natural grass. The outdoor carpet consists of a backing material with the 'pile' made of a propylene yarn inserted on a loom and manufactured in a manner similar to a normal indoor carpet. [0013] Synthetic grass surfaces are typically laid over compacted earth bases of materials such as crushed rock ('roadbase'), crusher dust or decomposed granite. Some are installed on a concrete overlay. [0014] There is a wide variation in structure and characteristics of synthetic surfaces. However one of the more popular versions of SFAG comprises 19mm pile height, 10,000 denier carpet with an average of 21 stitches to 100mm or 210 stitches to 1.00metre, a gauge of 10 mm, 19mm pile height and filled with a majority of 750 micron "rounded" particles, preferably of a dark coloured sand. [0015] The wide variation in synthetic surfaces matches the wide variation in player surface preferences. Different players favour different surfaces. With reference to SFAGs preferences exist for grip or slide, hard or soft, high sand levels or low sand levels, 'standard' pile height or short pile, etc. Furthermore tennis balls can often react quite differently on each of the various synthetic grasses available. [0016] Governing bodies can also influence the types of surfaces used. For example, at the current time, Tennis Australia will not sanction any professional tournament or elite junior tournament on synthetic grass or synthetic clay surfaces. In their opinion, hardcourts provide opportunities for a more tactical game where the court speed and foot grip encourage players to plan several strokes ahead of the winning shot. It is for this reason that Tennis Australia encourages the use of hardcourts for developing juniors. Conversely, synthetic grass properties encourage players to end a rally early.

5 [0017] Synthetic grass tennis courts became extremely popular in the 1980's and proliferated in tennis clubs at that time. [0018] However, due to various factors such as changing player preferences or a desire to hold higher level tournaments, a large number of tennis clubs have converted from SFAG surface to hardcourt. Furthermore, some councils have had a need to convert SFAG surfaces used for tennis and other sports to a harder surface suitable for other uses. [0019] Furthermore, although SFAG courts are low maintenance, the cost of maintenance is comparatively high. [0020] Replacing an SFAG surface with a solid surface requires a large amount of labour to remove the SFAG from the sub-base. Once torn off its sub-base the SFAG surface is extremely expensive to dispose of. Removing the SFAG often damages the sub-base, particularly if the sub-based includes poor quality concrete, and many SFAGs have been laid on sub-bases that were not very robust. Accordingly it is often necessary to remove and replace the existing sub-base before a hardcourt surface can be installed. This is an added expense and the added work to remove the sub-base extends the period of time that the court is out of action. [0021] The demolition, disposal and replacement of the sub-base typically costs between US$20,000 and $40,000 in addition to the cost of laying the new hardcourt surface. This is often cost prohibitive for tennis clubs and other organisations. [0022] Accordingly there is a need for a more efficient and economic method of replacing synthetic grass surfaces with solid sub-bases or artificial surfaces. SUMMARY OF INVENTION [0023] An object of the present invention is to provide a method of producing an artificial surface or base suitable for laying an artificial surface.

6 [0024] Another object of the present invention is to provide a method of converting a synthetic grass surface to a solid surface. [0025] Another object of the present invention is to provide a method of converting a particulate sub-layer once used to support synthetic grass to a solid surface or base suitable for installation of a solid surface. [0026] A further object of the present invention is to alleviate at least one disadvantage associated with the related art. [0027] It is an object of the embodiments described herein to overcome or alleviate at least one of the above noted drawbacks of related art systems or to at least provide a useful alternative to related art systems. [0028] In a first aspect of embodiments described herein there is provided a method for converting an existing surface to a base for a solid artificial surface, the method comprising the steps of: (i) applying a binder to form a bound surface, and (ii) applying a re-surfacer to the bound surface. [0029] Typically the existing surface is a synthetic grass surface comprising polymeric, typically polyethylene tufts, and particulate filer material such as sand. Alternatively the existing surface may be a particulate surface on which the synthetic grass surface had been laid such as crushed compacted blue metal (also know as basalt) or blue metal dust. [0030] The method may optionally include the further step of applying a filler coat, preferably an acrylic filler coat. [0031] In a second aspect of embodiments described herein there is provided a base made according to the aforementioned method. In a particularly preferred embodiment the base provides a surface suitable for playing sports.

7 [0032] Typically the binder is a water-based epoxy, such as a two-part epoxy. Most binders to not readily bind to synthetic materials such as the polyethylene used to make tufts of synthetic grass, however the presence of filler material such as sand aids binding and imparts rigidity. The binder is preferably comparable with low level moisture on application and imparts characteristics of water impermeability to the surface when cured. Optimally it has low viscosity and strong adhesion at least to the filler material. [0033] Typically the re-surfacer creates a hard surface and may be in the nature of a final sealer. Typically the re-surfacer comprises an epoxy and is applied subsequent to application of the binder. The re-surfacer may comprise any suitable liquid curable polymer capable of bonding to the synthetic surface to seal against ingress of liquid. [0034] The re-surfacer may be applied to the synthetic surface by any convenient means. In a particularly preferred embodiment the re-surfacer includes microspheres which enable the re-surfacer to be applied using a squeegee which is particularly advantageous for large surface areas. [0035] The solid surface thus formed is suitable for application of any convenient solid surface including cushioned and hard surfaces. [0036] In a third aspect of embodiments described herein there is provided a method for converting an existing surface to a solid surface, the method comprising the steps of: (a) forming a base by applying (i) a binder, and (ii) a re-surfacer, and subsequently (b) applying surfacing material to the base. [0037] The surfacing material may be chosen from a wide range of substrates including asphalt, concrete, a solid cushioned surface or a solid hard surface. Typically the surfacing material will be an acrylic based layer, or a liquid based rubber layer, or a mat system.

8 [0038] For example, suitable surfacing materials may be chosen from the following hardcourt systems: * acrylic non-rubberised hardcourt such as those sold under the trade mark Rebound SynpaveTM or Plexipave T M * cushioned acrylic hard court including a liquid based rubber such as those sold under the trade mark Rebound Ace ProTM; or * cushioned acrylic hard court including pre-formed particulate rubber cushioning such as those sold under the trade mark Rebound Ace HSA ClubTM or Ace GS 8TM or Air Cushion TM [0039] In a fourth aspect of embodiments described herein there is provided a method for converting an existing surface to a solid surface, the method comprising the steps of: (a) forming a base by applying (i) a binder, and (ii) a re-surfacer to the synthetic surface, (b) applying a hardcourt system to the base. [0040] Typically the hardcourt system includes a layer of particulate rubber, or a cured liquid rubber layer or a mat system. [0041] In a further aspect of embodiments described herein there is provided a method for converting an existing artificial surface to a solid surface, the method comprising the steps of: (a) forming a base by applying (i) a binder, and (ii) a re-surfacer to the artificial surface, (b) applying a porous layer to the base, 9 (c) applying a sealant to the porous layer, (d) applying a fibre reinforced adhesive layer to the sealant; and (e) applying a top coat to the upper surface of the sealant. [0042] Typically the porous base layer is formed from a matrix of liquid polyurethane mixed with resilient particles. [0043] Typically the sealant applied to the porous layer is polymeric. Preferably the sealant comprises a cross-linkable liquid polyurethane. [0044] The fibre reinforced adhesive material may be formed by applying to the sealed surface a liquid polymer containing chopped strand fibres. Alternatively, the layer of fibre reinforced adhesive material may be formed by adhering to the sealed surface a layer of woven or non-woven fibrous cloth impregnated with polymeric adhesive. The polymeric adhesive may comprise a liquid polymer such as an aqueous latex and suitably the liquid polymer is comprised of flexible cross-linkable polyurethane or acrylic polymer or copolymer. [0045] Typically the top coat is a pigmented acrylic polymer which acts as a playing surface or wear layer. The acrylic wear layer may comprise a conventional acrylic paving compound. [0046] In another aspect of embodiments described herein there is provided a hard surface comprising: (a) a base comprising a synthetic grass encapsulated by a binder, and a re surfacer, (b) a porous layer adjacent the base, (c) a sealant adjacent the porous layer, 10 (d) a fibre reinforced adhesive layer adjacent the sealant; and (e) a top coat adjacent the upper surface of the sealant. [0047] The hard surface thus formed may be suitable for a wide range of applications such as sport, recreational activities, garden landscaping, interior and exterior architectural features, pathways and roadways. In particular it is anticipated that the present invention will be utilised in the conversion of synthetic grass tennis courts to hardcourts. Typically this type of conversion of a tennis court would be approximately 1

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10 th to 1

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5 th of the cost of demolishing, disposing and replacing a synthetic grass tennis court. [0048] In yet a further aspect of embodiments described herein there is provided a synthetic sporting surface made in accordance with the method of the present invention. [0049] Other aspects and preferred forms are disclosed in the specification and/or defined in the appended claims, forming a part of the description of the invention. [0050] In essence, embodiments of the present invention stem from the realization that existing synthetic grass surfaces can be transformed into a solid base suitable for supporting other types of surfaces. [0051] Advantages provided by the present invention comprise the following: * an economic alternative to demolishing, disposing and replacing a synthetic grass tennis court with a new hard court, * does not disturb the existing sub-base structure of a synthetic grass, hence no need to replace or rebuild same, * conversion of an existing artificial surface to a solid base can be carried out in about 2 to 3 days, reducing the time the court is out of action.

11 [0052] Further scope of applicability of embodiments of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure herein will become apparent to those skilled in the art from this detailed description. BRIEF DESCRIPTION OF THE DRAWINGS [0053] Further disclosure, objects, advantages and aspects of preferred and other embodiments of the present application may be better understood by those skilled in the relevant art by reference to the following description of embodiments taken in conjunction with the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the disclosure herein, and in which: Figure 1 illustrates a cross sectional view of a surface according to the present invention having a base comprising a synthetic grass (3) encapsulated by a binder (5), and a re-surfacer (7) on a compacted earth sub-base of crushed rock or the like (2). The sub-base is undisturbed by this embodiment of the process of the present invention and can comprise any suitable sub-base known in the art including crushed rock or concrete. The synthetic grass includes tufts of polyethylene (3a) woven into a synthetic backing material (3b) with particulate filler (3c). This surface can be used as a base onto which other surfacing materials may be laid. Alternatively the surface of Figure 1 can be used for recreation or sport, preferably after the application of an acrylic top coat and optional line markings. Figure 2 illustrates an existing surface comprising particles of compacted crushed blue metal and blue metal dust (10) which had previously provided the base for a synthetic grass surface (now removed). A binder (12), and a re-surfacer (14) have been applied according to the method of the present invention. This surface can be used as a base onto which other surfacing materials may be laid. Alternatively the surface of Figure 1 can be used for recreation or sport, preferably after the application of an acrylic top coat and optional line markings.

12 Figures 3 to 6 illustrates the known types of surfacing materials that can be applied to a base created according to the method of the present invention and include well known surfacing systems known as Rebound ClubTM (Figure 3), Rebound Ace Pro T M (Figure 4), Synpave T M (Figure 5), and Ace T M (Figure 6). DETAILED DESCRIPTION [0054] Conversion of a SFAG surface tennis court to an artificial solid surface requires consideration and preparation of the relevant area. For example the court is preferably configured so that when it is sealed it has a 1% slope from one side for water/rain run off. In most cases the court will have such a fall to a natural drainage point. [0055] It is important to consider drainage needs before the surface is sealed. For example: * storm water points may need to be installed, * where multiple courts exist, division of drainage or installation of spoon drains should be considered, * critical court polarity should be measured and low points/ponding areas identified for building up, * where alterations for drainage are made, it is important that the synthetic grass be maintained, typically by rolling back the carpet and re-laying it over the altered sub-base. [0056] It is also important that the condition of the court with regard to mould and sand is considered. For example it may be necessary to: * treat the court for mould, 13 * top up the sand to an optimum level that is consistent over the entire court and surrounds, allowing sufficient time for good compaction, and * ensuring that the court is not overly moist. [0057] Binder: Once the SFAG is appropriately prepared, the binder may be applied. Preferably a clear water-based epoxy binder (5) is applied over the entire court surface at an even rate of about 3 to 5 litres/m 2 to a depth of about 2mm and saturating the particulate filler (3c). The surface should remain undisturbed and not walked upon while it cures for a period of about a day. After curing the court should be inspected to ensure a hard, consistent finish. In any areas whether the particulate (3c) filler saturated with binder (5) is not hard and compact, the binder (5) should be re-applied and allowed to cure for a further day. [0058] Re-surfacer: The next step is to apply an epoxy re-surfacer (7), which is trowelled onto the surface using a squeegee at a rate of 3 litres/m 2 then allowed to cure for a day. The cured re-surfacer should be inspected for polarity and any protruding tufts (3a) of polyethylene 'grass'. The entire surface should be lightly sanded to reduce raised areas and eliminate protruding tufts. Further re-surfacer (7) should be applied to any depressions in the surface. [0059] Figure 2 illustrates an existing surface comprising particles of compacted crushed blue metal and blue metal dust (10) which had previously provided the base for a synthetic grass surface (now removed). A binder (12), and a re-surfacer (14) have been applied according to the method of the present invention. This surface can be used as a base onto which other surfacing materials may be laid. Alternatively the surface of Figure 1 can be used for recreation or sport, preferably after the application of an acrylic top coat and optional line markings. [0060] Figures 3 to 6_illustrates the known types of surfacing materials that can be applied to a base created according to the method of the present invention and include well known surfacing systems. Typical surfacing materials and constituent layers are described in International patent publication WO 88/06971.

14 [0061] In particular, Figure 3 illustrates the surfaces known as Rebound Club T M (Figure 3) laid on a base (20) according to the present invention. The base (20) is overlaid with mat adhesive (22), a rubber shock pad (24), two coats of a mat sealer (26), then a layer (28) of high impact material (in the case of the Impact T M system) or two layers of flexible filler coat (in the case of the Club T M system). Finally the surface is finished off with two coats of acrylic (30) to which line markings can be applied. [0062] Figure 4 illustrates the surface known as Rebound Ace ProTM laid on a base (20) according to the present invention. The base (20) is overlaid with two layers of base coat (32), two to six coats of a liquid rubber (34, 36), two layers of filler coat (38). Finally the surface is finished off with two coats of acrylic (40) to which line markings can be applied. [0063] Figure 5 illustrates the surface known as Synpave T M laid on a base (20) according to the present invention. The base (20) is overlaid with a base coat (42), two layers of acrylic filler (44, 46) and finally two top coats of acrylic (48) to which line markings can be applied. [0064] Figure 6 illustrates the surface known as Ace T M laid on a base (20) according to the present invention. The base (20) is overlaid with a mat adhesive (52), a rubber shock pad (54), two layers of mat sealer (56), a reinforced layer (58), two layers of filler coat (60) and finally two layers of acrylic (62) forming the playing surface to which line markings may be applied. [0065] While this invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification(s). This application is intended to cover any variations uses or adaptations of the invention following in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth. [0066] As the present invention may be embodied in several forms without departing from the spirit of the essential characteristics of the invention, it should be understood 15 that the above described embodiments are not to limit the present invention unless otherwise specified, but rather should be construed broadly within the spirit and scope of the invention as defined in the appended claims. The described embodiments are to be considered in all respects as illustrative only and not restrictive. [0067] Various modifications and equivalent arrangements are intended to be included within the spirit and scope of the invention and appended claims. Therefore, the specific embodiments are to be understood to be illustrative of the many ways in which the principles of the present invention may be practiced. In the following claims, means-plus-function clauses are intended to cover structures as performing the defined function and not only structural equivalents, but also equivalent structures. [0068] "Comprises/comprising" and "includes/including" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. Thus, unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', 'includes', 'including' and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

Claims (6)

1. A method for converting an existing surface to a base for a solid surface, the method comprising the steps of: (i) applying a binder to form a bound surface, and (ii) applying a re-surfacer to the bound surface.

2. A method according to claim 1 wherein the binder and re-surfacer are applied to a compacted crushed rock surface.

3. A method according to claim 1 wherein the binder and re-surfacer are applied to a synthetic grass surface and particulate filler.

4. A base made according to the method of claim 1.

5. A method for converting an existing surface to a solid surface, the method comprising the steps of: (a) forming a base by applying (i) a binder, and (ii) are-surfacer, and (b) applying surfacing material to the base.

6. A method according to claim 1 and substantially as herein disclosed with reference to the drawings.