AU772058B2

AU772058B2 - Removable ground marking system

Info

Publication number: AU772058B2
Application number: AU71927/00A
Authority: AU
Inventors: John Woodhouse
Original assignee: SUPATURF AUST Pty Ltd
Current assignee: SUPATURF AUST Pty Ltd
Priority date: 1999-11-30
Filing date: 2000-11-30
Publication date: 2004-04-08
Anticipated expiration: 2020-11-30
Also published as: AU7192700A

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant: SUPATURF AUST PTY LTD Invention Title: REMOVABLE GROUND MARKING SYSTEM The following statement is a full description of this invention, including the best method of performing it known to me: 2 REMOVABLE GROUND MARKING SYSTEM FIELD OF THE INVENTION The present invention relates to a system for marking a ground surface and removing the markings, and to the paint and remover of the system. The invention also relates to a method of removably marking a ground surface, and methods for making the paint and remover.

BACKGROUND OF THE INVENTION Line markings on athletic grounds are imperative in defining boundaries and other game markings in sports.

One ground is often used for multiple sporting disciplines, each requiring different line markings. The old line markings therefore need to be removed to allow marking of new lines for a different sport. It is important that the old lines are removed as much as possible to avoid confusion with the new lines. Lime powder has for years :been used for marking lines on outdoor playing fields, but takes some effort to remove requiring brushing or rinsing with water. One problem with lime powder is that it is not water resistant and is susceptible to washing away in the rain.

More recently, grounds are being marked with water based and water resistant paint, or regular house paint, which can be applied with a smooth roller, transfer 30 marker or by being sprayed onto the ground. Whilst the paint is water resistant it cannot be removed easily or without damage to the surface. This has forced the practice of "greening out" old lines, by applying a green paint over the old lines to camouflage the lines with the grass. While the colour of the line marking is removed, this practice does not remove all trace of the line because the green colour of the paint rarely matches the exact colour of the grass. Further, the smoother texture of the H:\dregel\Keep\P40465 REMOVABLE GROUND MARKING SYSTE.doc 30/11/00 3 green paint reflects more light than grass thereby highlighting the old lines.

A further concern is the environmental affect the paint has on the grass and surrounding soil. The constant greening out of old lines kills turf by smothering the grass and results in paint chemicals such as solvents, bactericides and fungicides infiltrating the grass root zone in the soil. Once the soil is contaminated, it is no longer suitable for growing grass.

The problem is even greater with the recent move to mark grounds with team logos and advertising logos.

Removing the logos requires greening out of a larger area and of a variety of colours. A considerable amount of green paint is needed for the greening out and the results are often less than satisfactory. The dead grass killed by repeated marking must be replaced with expensive replacement patches of grass farmed off-site.

Environmentally friendly starch, or the like, based paint has been tried as an alternative line marker, but unsuccessfully as this type of paint dissolves in water, and is therefore not suitable as a line marking in 25 wet conditions.

There is therefore a need for a line and logo marking medium that is water resistant, can be easily removed and has minimal impact on the environment.

SUMMARY OF THE INVENTION ""According to the present invention there is •go provided a method of applying and removing markings on a ground surface comprising the application of a removable paint at one stage and the removal of the paint at a later stage; H;\lauraw\Keep\Speci\71927-00dOC 18/02/04 4 the application including applying the paint to a ground surface to create a marking, wherein the paint contains pigment and an alkali removable binder, and is water resistant when allowed to dry on the surface; and the removal of the paint including treating the dry paint with an aqueous alkali remover which dissolves the paint into a water soluble state so that the paint can be easily removed from a ground surface without scrubbing.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT The present removable ground marking system comprises a removable paint and a paint remover. The removable paint is suitable for marking ground surfaces including natural and synthetic grass, bitumen, packed soil, and the like. Special reference to application on natural grass is made in the present description.

The paint is an alkali removable paint composition containing pigment and an alkali removable binder. Specifically, the binder is an alkali soluble polymer, and more particularly, a styrene acrylic polymer or an acrylic polymer. The paint composition also :contains a thickener and other standard paint components 25 or additives.

In the preferred embodiment of the removable ground marking system the paint comprises approximately 40%-70% thickener, 10%-30% alkali soluble polymer, 10%-25% white pigment and 1%-10% other additives such as defoaming agents, coloured pigment and pH neutralisers. The alkali oooo soluble polymer is a styrene acrylic polymer emulsion that is mixed with pigment, thickener and other additives to make the removable paint. The polymer comprises 42% 35 solids, has a pH of 6.3 and a viscosity of less than 100 ooooo H:\lauraw\Keep\Speci\71927-OO.doC 18/02/04 THIS PAGE IS INTENTIONALLY LEFT BLANK H.\lauraw\Keep\Speci\71927-OO.doc 12/11/03 6 cps (centipoise). Given that the removable paint of the present invention is intended to be applied to ground substrates with the view of removal in the short term, the paint components need not have high adhesion and durability usually required of paint compositions for standard surface applications, such as paints for building exteriors. The present paint constituents are, however, capable of withstanding for a suitable period of time wear from underfoot trampling, precipitation and other weather conditions.

The paint is coloured with pigment as desired, then diluted with an approximately equal volume of water to enable the paint to be more easily applied onto grass. The paint is applied to the grass surface with a smooth roller, transfer marker, airless spray machine or by any other suitable means, and then allowed to dry. The paint can also be sprayed onto grass surfaces with a regular spraying machine but first requires a greater dilution at an approximate proportion of 1:2. This method of application is particularly suitable for marking lines in wet S" conditions where it is more difficult to achieve line markings with direct transfer.

The styrene acrylic polymer binder-containing paint is insoluble and therefore water resistant when dry.

When water in the paint marking evaporates the alkali soluble binder forms a film on the ground surface binding the pigment to the surface. It will not wash away or discolour in rain.

The paint remover is an aqueous alkali solution which removes the dried alkali soluble paint. Removal is preferably by dissolution of the paint, as opposed to merely softening the paint, thereby allowing it to be rinsed away from the surface or rinsed then lifted off the surface. The remover additionally contains a surfactant that aids in dissolving the paint. The surfactant can be H:\dregel\Keep\P40465 REMOVABLE GROUND MARKING SYSTEM.doc 30/11/00 7 any suitable known surfactant. Coloured dye is also added to the remover so that application of the remover can be visibly monitored.

In the preferred embodiment, the alkali solution contains ammonia or a substituted or unsubstituted amine.

Ammonia-based alkali solutions are not preferred on natural grass surfaces as they can damage the grass. Suitable remover solutions contain a non-toxic substituted or unsubstituted amine, such as 2-amino-2-methyl-l-propanol (an amine including alkyl and hydroxy substituents).

Preferably the alkali remover has a pH of between 8 and 11, and more typically about 9 or 10. This pH level is both sufficient to effect removal of the paint and is at the same time not likely to damage the ground surface at the concentration used. In particular, the remover solution is innocuous on the grass blades, unlike other forms of paint removers. Rather, the present nitrogen based remover solution is more likely to assist grass fertilisation.

To remove the line or logo marking, the remover is diluted with water at about 1:20 then sprayed onto the dry marking where it is allowed to penetrate the marking for approximately 2-5 minutes. The alkali base in the remover dissolves the polymeric binder in the paint causing the paint to become water soluble, such that it can be removed with a water hose or a water spray machine. The 30 paint has an overall low solid content at application and contains no solvents, bactericide or fungicide. Hence, the paint is environmentally friendly and dissipates into the soil profile and leaving minimal residue. The remover too is water based and thus friendly to the soil or grass when applied under the specified conditions.

Examples of paint and remover compositions of the present ground marking system are provided in Tables 1 and H:\dregel\Keep\P40465 REMOVABLE GROUND MARKING SYSTEM.doc 30/11/00 8 2 below.

Table 1: r PAINT

PERCENTAGE

Water 63.15 Hydroxy ethyl cellulose 0.50 thickener Titanium dioxide 10.00 Alkali soluble polymer 20.00 (styrene acrylic) De-foaming agent 00.10 Acrylic thickener 06.00 Alkali solution 00.25 Application dilute 1:1 with water Table 2: REMOVER PERCENTAGE Water 47.75 Alkali solution 50.00 Surfactant 02.00 Dye 00.25 Application: Dilute 1:20 with water Table 1 shows that water makes up more than half of the paint mixture with the styrene acrylic polymer amounting to 20% of the paint content prior to dilution for application. Titanium dioxide, or white pigment, constitutes 10% of the mixture whilst thickener constitutes A de-foaming agent and an alkali solution make up a small amount of the total mixture. The alkali solution neutralises the pH giving the paint a pH of approximately H: \dregel\Keep\P40465 REMOVABLE GROUND mARKINCSySTEM.doc 30/11/00 9 7-8, which is common in providing a stable paint composition.

Table 2 illustrates the remover comprising mostly water and alkali solution with 2% surfactant, and a trace of dye.

Removal of the paint from a grass field is made easier if the removable paint is only applied to the leaf area of the grass and any application to the soil surface is avoided. This is achieved by using a foam paint (smooth) roller, transfer marker or an airless spray unit.

It is important in this case that the paint is of a sufficient viscosity at application so as to minimise paint flowing down the blades of grass and entering the root zone of the grass. A high pressure, low volume water jet system will successfully remove almost all the marking. Direct agitation, for example with a rotary brush, can be used in conjunction with the water jet system for total removal.

20 An alternative to using high pressure water to remove markings is to use a water vacuum, super sopper or the like. This also minimises any chemicals from entering the soil profile.

The paint contains white pigment (titanium dioxide) but can be coloured as desired by simply adding the appropriate colour pigment.

To coat the ground with the paint, a quantity of 30 water is added to an equal part of paint and the mixture is applied to the ground using the appropriate means described above. Applying the paint to only the leaf area of the grass will make removal of the marking easier. When the paint is allowed to dry it becomes water resistant and suitable for use on any grass field in any conditions. It is understood that the term "grass" includes synthetic grass as well as natural grass.

H:\drege\Keep\P40465 REMOVABLE GROUND MARKING SYSTEM.doc 30/11/00 10 To remove a line or logo marking from a grass field, the alkali remover solution is sprayed on top of the dried marking and allowed to stand until the alkali dissolves the paint marking into a soluble form. This takes approximately 2-5 minutes. The liquid paint is then removed from the field by either rinsing into the soil with a hose or extracting it from the grass using a vacuum-type machine. -Removal is assisted by emulsifying the paint with the surfactant.

The present system provides a friendly water based, water resistant line marking which is able to be removed at will. This allows the grass to "breathe" between line applications rather than being "smothered" by greening out markings which are no longer needed.

The paint is removed with minimal effort, yet can confidently withstand any weather conditions. Any residue that does enter the soil is minimal and will not destroy 20 the soil's capacity to nurture grass.

ooo o The present removable ground marking system allows efficient and effective application and removal of markings to accommodate different sporting disciplines.

Whilst it is envisaged that the marking system will be largely used for marking sports grounds, it is understood that it may be equally applicable for decorative purposes or any other purpose where ground surface markings may be required. It is envisaged that in addition to marking 30 natural and synthetic grass surfaces, the removable ground marking system can also be used on other suitable substrates such as bitumen, concrete, en tout cas, packed soil, etc.

It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention.

H:\dregel\Keep\P40465 R4OVABLE GROUND MARKING SYSTEM.doc 30/11/00 11 In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

00..i

Claims

2. The method claimed in claim 1 including diluting the removable paint with water before applying it to the ground surface.
3. The method claimed in claim 1 or 2 including applying the paint to the ground surface by way of a smooth roller, a transfer marker, a broom, an airless spray machine or the like. 25 4. The method claimed in any one of the preceding claims including diluting the remover with water before coating the dry paint to achieve a water content of approximately 30 5. The method claimed in any one of the preceding o:oo °o claims wherein the step of removing the paint includes the steps of applying the aqueous alkali remover to the paint to solubilise the paint and washing the dissolved paint °ooo away with water. S• 6. The method claimed in claim 5 further including the step of removing the dissolved paint by lifting it off the H:\lauraw\Keep\Speci\71927-OO.doc 18/02/04 13 ground with a vacuum apparatus.
7. The method claimed in any one of the preceding claims including applying the removable paint to natural or synthetic grass.
8. The method claimed in claim 7 including applying the paint only to the leaf area of the grass.
9. The method claimed in any one of the preceding claims wherein the binder is an alkali soluble polymer. The method claimed in claim 9 wherein the polymer is a styrene acrylic polymer or an acrylic polymer.
11. The method claimed in any one of the preceding claims wherein the paint additionally contains thickener.
12. The method claimed in any one of the preceding claims wherein the paint additionally contains a pH neutraliser and de-foaming agent.
13. The method claimed in any one of the preceding claims wherein the alkali remover has a pH of between 25 8-11.
14. The method claimed in claim 13 wherein the alkali remover has a pH of between 9-10. 30 15. The method claimed in any one of the preceding claims wherein the alkali remover contains a substituted or unsubstituted amine which dissolves the binder. 0*
16. The method claimed in claim 15 wherein the alkali 35 remover contains 2-amino-2-methyl-l-propanol. 0 H.\lauraw\Keep\Speci\71927-OO.doc 18/02/04 14
17. The method claimed in claim 2 wherein the remover contains at least 80% water.
18. The method claimed in any one of the preceding claims wherein the remover contains a surfactant.
19. A method of applying and removing markings on a ground surface substantially as hereinbefore described with reference to the accompanying examples. Dated this 18 t h day of February 2004 SUPATURF AUST PTY LTD By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia V. 0:0 *see o...oo g *go oo H\lauraw\Keep\Speci\71927-OO.doc 18/02/04