US20110078851A1

US20110078851A1 - Surface composition and method of application

Info

Publication number: US20110078851A1
Application number: US12/996,726
Authority: US
Inventors: Lew Beale
Original assignee: Hydrawall Pty Ltd
Current assignee: Hydrawall Pty Ltd
Priority date: 2009-02-23
Filing date: 2009-12-23
Publication date: 2011-04-07
Also published as: AU2009340370B2; KR101850157B1; CA2752387C; US20110315064A1; WO2010094080A1; JP2012518689A; CN102325950B; EP2398978A4; MY160356A; CA2752392C; JP5600691B2; AU2009340370C1; AU2009340370A1; WO2010094056A1; EP2262961B1; EP2398978A1; NZ594588A; AU2010215081B2; CA2752392A1; CN102325949A

Abstract

A surface composition for reducing degradation and fading of surfaces subjected to extended periods of submersion in an aqueous liquid includes at least one clear barrier layer and at least one under layer, wherein the clear barrier layer is in use, disposed atop the under layer and in contact with the aqueous liquid whereby the clear barrier layer protects the structure and appearance of the under layer. The clear barrier layer provides structural protection against degradation from chemical attack and from fading due to UV exposure.

Description

FIELD OF THE INVENTION

The present invention relates to a surface composition for use in protecting surfaces subjected to extended periods of submersion from degradation and fading, such as protecting a surface layer finish of swimming pools and spa pools. The present invention also relates to a method of application of a surface composition and to products manufactured therefrom.

BACKGROUND TO THE INVENTION

Swimming pools and spa pools can be installed for private or public use and for a variety of different uses, such as competition, exercise, recreation, relaxation or therapy. Construction methods for pools can vary, though the in-ground version is most popular if the pool is to remain as a permanent fixture. The main types of in-ground pools are concrete, fibreglass reinforced plastic (FRP) and vinyl-lined pools.
Fibreglass pools are typically the most popular for private installations, such as those installed at a private residence. Fibreglass pools are made from fibreglass reinforced plastic which has been moulded into a basin shape, which is the final shape of the pool. The shape and configuration of the pool is dependent on that of the mould. Typically, any one pool manufacturer will have a set selection of moulds that a consumer can select their pool design from.
Selection of the shape and size of the fibreglass pool is one important decision that the consumer must make when selecting their pool. Arguably the other most important decision is selection of the pool surface finish, which dictates the appearance the pool will have when filled with water. Selection of surface finish can include selection of colour, sparkle or shimmer, the combination of which can match the appearance of the pool to its surroundings as well as give the appearance of colour depth and brilliance as well as capture marble or granite effects.
Regardless of the shape of the pool or the surface finish selected, it is common to all fibreglass pools that once installed, the surface is totally immersed in water and remains as such interminably. That is, the water is never completely discharged and remains within the pool structure at all times. This inevitably creates a two-fold problem. The first is that the water itself, which is typically of a temperature between 12 to 41° C., is a harsh solvent capable of dissolving any water soluble material (WSM) and hydrolysing any of the water soluble components used in manufacture of the pool.
The second problem is that the water must be sanitised in order to kill algae and pathogens such as bacteria and protozoa, since without sanitisation; the pathogens will otherwise thrive in the water, creating a perfect place for micro-organisms to transfer from one person to the next. Pool filter systems can assist in keeping the water clean; however, to properly take care of water pathogens, it is necessary to introduce a disinfecting agent into the water.
The most popular pool disinfectant is chlorine, which can be introduced in various forms, such as calcium hypochlorite or sodium hypochlorite. Chlorine is also produced by the electrolysis of salt, commonly called “salt water chlorinators”. When these compounds are added to water, the chlorine component reacts to form various chemicals, including hypochlorous acid, which acts to kill the pathogens. Alternative sanitizers such as bromide, ozone or hydrogen peroxide carry out essentially the same disinfecting function.
Since hypochlorous acid is not a particularly stable compound, it is usually necessary to add further chemicals to the pool water, including stabilising agents such as cyanuric acid. Further, pH level of the pool water is desirably maintained at generally neutral levels (a pH between 7 and 7.8), since water that is either too acidic or too alkaline will cause undesirable chemical reactions. Further chemicals are typically added to the pool water to maintain the pH, such as sodium carbonate or sodium bicarbonate to raise the pH and sodium bisulfate or liquid acids such as hydrochloric or sulphuric acid.
The combination of this chemical cocktail in an aqueous environment eventually causes bleaching and degradation of the pool surface. Over time, there are usually clear signs of fading and deterioration of the pool surface which significantly detracts from the aesthetic appearance of the pool. Fading and deterioration problems are increased by a variety of other factors such as:

- a) exposure to UV light, particularly when the pool is located outdoors;
- b) neglect and mismanagement of the pool, including incorrect application of chemicals by the consumer;
- c) elevation of water temperature due to heating and application of spa pools, which exacerbates the process of degradation by the water and chemicals; and
- d) use of automatic sanitisers, salt water chlorinators and pH controllers, which can lead to overdosing of the pool with acids, alkalis and oxidising agents outside the effective operational parameters of the products.
- e) continuous exposure to water and the hydrolysing effects of the water.

Despite these problems, consumer expectations demand a product which can withstand degradation and importantly, retain the original colour for extended periods of time and without necessitating costly and time consuming stripping and refurbishing of the pool surface or even replacement of the pool itself, which are the only permanent and consumer acceptable remedies once degradation of the pool surface has occurred. Similarly, manufacturers of pools, who generally provide some degree of guarantee with pools, do not wish to become liable for repair or replacement if the pool surface cannot withstand degradation for a prescribed period of time.
Since the problem of surface degradation, including colour fading, is such a widespread problem, there have been various attempts to remedy or at least alleviate the problem. Such remedies includes the use of inorganic colour pigments such as metallic salts and oxides in preference to organic pigments, since the organic pigments, although generally more vibrant, are less stable. Another remedy is to produce pools in colours such as white, creams or very pale blue colours that simply show only minimal effects of fading. The unfortunate outcome of such remedies is that colour and finishing options then become severely limited.
Some success has been achieved by the application of the colour and decorative surface finish in a polyester gelcoat, the gelcoat having some UV resistant properties. However, although known gelcoats are able to offer a certain degree of resistance and longevity to the pool appearance, after about 6 to 10 years, the surface finish pigment inevitably starts to fade and the appearance of the pool becomes compromised and looks washed out.
Further, whilst it may at first seem a viable solution to protect the aesthetic, particularly the colour, qualities of the pool surface with the application of an additional protective or barrier layer, to date no such application has been successful in the unique circumstances of pools, where the pool surface is subject to prolonged periods of submersion.
There is therefore a need for a product which can prevent discolouration and degradation of the pool surface finish without compromising the availability of selection of colours and finishes.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a surface composition for reducing degradation and fading of surfaces subjected to extended periods of submersion in an aqueous liquid, the surface composition comprising at least one clear barrier layer and at least one under layer, wherein the clear barrier layer is in use, disposed atop the under layer and in contact with the aqueous liquid whereby the clear barrier layer protects the structure and appearance of the under layer.
The surface composition is particularly useful in applications where the surface is subjected to extended periods of submersion in liquids containing hydrolysing or oxidising agents, exposure to ultra violet radiation, or combinations thereof, whereby the clear barrier layer provides structural protection against degradation from chemical attack and from fading due to UV exposure.
In a particularly preferred embodiment of the invention, the under layer is a decorative layer, containing one or more decorative or ornamental agents provided to impart a desired visual or aesthetic appearance. The decorative or ornamental agents can include, but are not limited to, pigments, particles and chips.
The surface composition finds particular application in the creation of a surface finish to swimming pools and spa pools; particularly fibre reinforced plastic (FRP) pools.
The surface composition provides strong interlaminar bonding between the barrier layer and the under layer. As such, the surface composition of the invention advantageously minimises delamination and prevents osmotic blistering.
In one embodiment the composition comprises one or more UV inhibitors, absorbers and/or stabilisers. Preferably, the clear barrier layer comprises one or more UV inhibitors, absorbers and/or stabilisers.
In another embodiment the clear barrier layer is a clear polyester gelcoat. Preferably, the clear polyester gelcoat comprises one or more phthalate containing polyesters, vinyl containing polyesters or methyl methacrylate containing polyesters. More preferably, the clear polyester gelcoat comprises a phthalate containing polyester particularly a phthalate containing polyester derived from an isophthalic neopentyl glycol (iso-NPG).
The iso-NPG is advantageously combined with additives, including promoters and UV inhibitors/absorbers, which are added prior to application of the iso-NPG to a pool mould.
In one embodiment the barrier layer comprises a triazine based UV absorber. Additionally or alternatively the barrier layer comprises a hindered amine light stabiliser.
In a yet further embodiment the barrier layer comprises one or more metal promoters preferably one or more metal promoters selected from the group consisting of zinc octoate, potassium octoate or cobalt octoate. Particularly preferred promoters are a mixture of zinc octoate and potassium octoate.
The under layer comprises one or more polyesters, vinyl esters or terephthalate based resins. Preferably the under layer comprises one or more epoxy vinyl esters, brominated epoxy vinyl esters, novolac epoxy vinyl ester resins or elastomer modified vinyl ester resins. A particularly preferred under layer is an epoxy vinyl ester resin comprising a bisphenol-A epoxy vinyl ester resin.
In one embodiment the under layer comprises one or more metal promoters.
The under layer is provided with decorative additives such as pigments, which can include organic or inorganic pigments and optionally, other decorative elements, such as small chips or particles, so as to impart a granite, marble, crystalline or quartz appearance.
According to a further aspect of the present invention, there is provided a method of manufacturing a pool surface composition, comprising application of a clear gelcoat liquid to a pool mould, permitting the gelcoat to cure and subsequently applying a coloured or decorative vinyl ester layer to the cured gelcoat.
According to a yet further aspect of the present invention there is provided a use of a surface composition according to any of the aforementioned embodiments in the manufacture of a swimming pool or spa pool.
According to a still further aspect of the invention, there is provided a swimming pool or spa pool, the pool having a surface composition comprised of at least one clear barrier layer and at least one under layer wherein the clear barrier is in use, disposed atop the under layer and in contact with liquid in the pool, whereby the clear barrier layer protects the under layer from degradation.
Throughout this specification, use of the terms “comprises” or “comprising” or grammatical variations thereon shall be 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 not specifically mentioned.

BRIEF DESCRIPTION OF THE FIGURES

The present invention will now be described with reference to the accompanying Figures, where:

FIG. 1 is a simplified diagram of layers of a surface composition according to the present invention; and

FIG. 2 is a photograph comparing effect of submersion and chemical exposure on a panel of FRP of known surface composition and of a surface composition of the present invention.

FIGS. 3 to 14 are photographs of a series of test panels comparing weathering resistance.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

The present invention as described hereafter is a description of preferred embodiments of the invention and should be understood as being a description for purposes of demonstrating non-limiting examples of possible embodiments of the invention. The embodiments and examples described do not define the overall broader scope of the invention.
The surface composition of the present invention finds particular application in the creation of a surface finish or layer in FRP swimming pools and pool spas, in which the surface is submersed within and in direct contact with water, particularly water containing hydrolysing and/or oxidising agents, such as from pool sanitising chemicals, for prolonged periods of time. The surface composition has the primary object of not only maintaining structural integrity of the FRP product whilst immersed in water, but also of protecting decorative elements such as pigmentation, from damage or fading caused by prolonged exposure to water, chemicals and UV radiation.
The surface composition includes a clear barrier gelcoat surface layer which is in use, in direct contact with the water and any chemicals that the water may contain. The purpose of the clear barrier layer is to protect the second gelcoat layer, this second, or decorative layer containing decorative components or additives, such as pigmentation and chips or particles, from degradation by the water, chemicals and UV light. That is, the clear barrier layer, applied to a pool or spa pool mould prior to application of the second, decorative or coloured gelcoat layer, has the purpose of protecting the decorative qualities within the second layer, the maintenance of which is essential in preserving the cosmetic or aesthetic qualities of the pool.
To date, there has been no successful application of a clear barrier layer to protect the qualities of a decorative under layer in the unique circumstances where the surface is subjected to prolonged periods of submersion and also often to prolonged UV radiation exposure. One of the main reasons as to why a clear gelcoat has not been successfully applied prior to the application of a second coloured gelcoat is that the application of two like gelcoat substances on top of each other will eventually fail when fully submersed in water and subjected to hydrolysis and osmotic pressure. Compounding the problem, the required heavy use of pigments and physical reagents prevents adequate bonding between the two surfaces. In previous attempts, osmotic blisters have developed at the interface of the two layers which not only detracts from the aesthetic quality of the pool but compromises structural integrity. To date, application of a clear polyester gelcoat over another, coloured or decorative polyester gelcoat has failed in any application to pool surfaces.
In other attempts, which have sought to use different materials, the inherent qualities of the selected materials, whilst possessing structural qualities suitable and necessary for use in a pool surface composition, have partly contributed to the failures. Base resins used to make gelcoats are often themselves not clear since the manufacturing process imparts a brown coloured quality to the resin. Further, the promoters or accelerators necessary for curing the resin at room temperature are generally cobalt based, which are purple in colour and therefore also alter the colour of the final resin. Also, the actual process of catalysation and setting of the resin similarly changes the colour. In short, once the resins are processed for spraying, they are no longer clear. It is generally undesirable to manufacture pools having surfaces of such colours. In any event, use of resins which turn brown or purple prevent the use of the full array of colours and cosmetic effects that are available and desired by the consumer.
Some other attempts at providing a clear protective layer over the coloured layer have failed since the clear layer, once exposed to UV light, turns opaque or cloudy and the clarity of the protective layer is permanently lost.
The composition of the present invention has solved these issues by utilisation of specific components and additives in each of the clear barrier layer and the coloured, decorative layer located underneath.
In the presently described embodiment of the invention, the clear barrier layer of the surface composition of the present invention is provided as a clear polyester gelcoat such as a clear isophthalic neopentyl glycol (iso-NPG). Preferably, the iso-NPG is a high quality, high molecular weight iso-NPG. A non-limiting example of a suitable iso-NPG is the commercially available Cray Valley (Cray Valley Korea Co. Ltd) formulated gelcoat, Polycor GPLY 9107-011, which is an unsaturated polyester resin in styrene monomer.
Whilst this is a preferred composition for the clear barrier layer, it is envisaged that a selection of other suitable products can also be used, such as, but not limited to, clear orthophthalic NPG based gelcoat, clear orthophthalic gelcoat, clear vinyl ester gelcoat or clear methyl methacrylate modified gelcoat.
Specific additives are added to the unpromoted iso-NPG to impart the qualities needed to protect the second, decorative layer. In this embodiment, the additives include specific promoters and UV inhibitors and/or UV absorbers.
The specific choice of added promoters (accelerators) is one of the chief factors in the success of the application of the clear barrier gelcoat layer and its inclusion in the present surface composition. It is usual in the art of FRP pool manufacture, that the promoter of choice is cobalt based, namely cobalt octoate, which is purple in colour. The addition of this component alone is sufficient to alter the colour of the resin, making it less than clear.
In the present invention, mixed metal promoters are added to the iso-NPG. Preferred metal promoters are zinc octoate (6%) and potassium octoate (12%), which, on being added to the iso-NPG, do not alter the colour. Further, even on catalysation and curing, they do not alter the clarity of the gelcoat.
Whilst zinc octoate and potassium octoate are preferred promoters, it is probable that others may also be suitable. Other products that can suitably be used in the process include, but are not limited to, SHEN catalyst PC-6, EFKA-2020 defoaming agent, dimethyl aniline and some small amounts of cobalt octoate (6%).
The selection of added promoters is important also in that the particular selection of mixed metal promoters have solved curing difficulties with the application of iso-NPG. Iso-NPG's, whilst having physical qualities that are ideal for the present application, being known to be more hydrolytically stable than other resins such as orthophthalic resins, are more difficult to apply and more difficult to process. For at least this reason, iso-NPGs have been considered as unsuitable for purposes of providing a clear barrier gelcoat or indeed, even for general widespread application in creation of FRP pools. High molecular weight iso-NPG's are more reactive and are prone to shrinkage from the mould if applied too thickly, or are over catalysed or promoted, or sprayed in less than ideal conditions. However, the selection of the mixed metal promoters such as zinc octoate and potassium octoate have overcome curing problems and permitted the creation of a clear layer having a strong positive cure.
So that the clear barrier gelcoat advantageously has qualities that will protect the coloured gelcoat layer from UV fading, at least one UV inhibitor and/or absorber or a light stabiliser is also added to the iso-NPG. In this particular embodiment, two UV absorbers are added, known commercially under the trade marks Tinuvin™ and Chimasorb™, each produced by Ciba™ Specialty Chemicals Inc. Preferred blends are Tinuvin™ 384-2 and Chimasorb™ 119FL. Particularly preferred blends are Tinuvin™ 400 and Tinuvin™ 123. These UV absorbers and stabilisers act to improve the resistance of the clear barrier gelcoat to UV exposure failures such as discolouration, cracking and fading.
Further additives are added to the iso-NPG as required, such as thixotropic agents. Selection of thixotropic agent is not of itself critical for the present surface composition to work, only to make the uncured components appropriately sprayable, which is necessary for the method of application of iso-NPG in creation of FRP pools known to the art. However, the thixotropic agent should be hydrophobic, so as to repel moisture. Elimination of moisture is necessary to maintain the clarity of the clear barrier gelcoat, since moisture will cause the gelcoat to become misty and detract from the aesthetic qualities.
The combination of specific components as described above advantageously provides a clear barrier gelcoat that can be sprayed onto the pool mould prior to the application of the second coloured gelcoat. The combination of components is clear prior to application and remains clear after application and curing. However, the successful creation of the clear barrier gelcoat cannot be successful in the intended application as a pool surface composition unless it also facilitates application of the second coloured gelcoat without wrinkling of the clear coat. It is also necessary that a strong interlaminar bond between the first and second gelcoats be created so as to eliminate possibility of delamination between the adjacent gelcoat layers.
In order to achieve these advantages and arrive at the surface composition of the present invention, the composition of the second coloured gelcoat is critical. In the present embodiment, the second colour gelcoat is comprised essentially of a vinyl ester resin.
Vinyl ester resins have properties which advantageously lend themselves to the present application, in that they are extremely strong, have great hydrolytic stability, offer excellent tensile and flexural strengths and have a high heat distortion temperature and are therefore able to resist osmotic blistering. In addition, they have excellent adhesive and bonding characteristics and are very chemically resistant. However, despite having these qualities, vinyl esters have never been used as a carrier for decorative agents such as pigment and texturising agents in pool surface compositions or in any application where the surface is exposed to water for prolonged periods. Vinyl esters are known to degrade when subjected to constant water submersion and continuous UV radiation. As such, any gelcoat made from a vinyl ester and applied to a pool surface will change colour on manufacture, on application and particularly after aging and exposure to water and UV light.
Further, vinyl esters have been thought to be inherently unsuitable for application in pool surfaces due to the fact that when used as a gelcoat, they characteristically cure softer than a polyester resin. That is, using a Barber Coleman impresser to test for Barcol hardness, a vinyl ester resin can test at about 25% lower than the hardness of an iso-NPG or ortho-NPG based gelcoat. As such, despite having many positive attributes, vinyl ester gelcoats are generally unable to withstand the rigors of pool usage, particularly from abrasion from cleaning products, cleaning methods and automatic pool cleaners.
However, the concept of the present invention, where the pigmented vinyl ester is protected from exposure to such elements by the clear barrier gelcoat, solves these difficulties and permits the advantageous qualities of the vinyl ester to be employed in the present application.
The vinyl ester resin selected for the present invention is one that is formulated to be clear and importantly, not show the distinguishing brown tones of conventional vinyl ester resins. Standard vinyl ester resins are brown and thus do not provide a good base for application of the available variety of different pigmentations. Since one of the objectives of the present invention is to permit the use of not only standard colours in pools, but an expanded array of colours as well as culturing and texturizing of colours with the addition of small chips or particles, it is desirable that the vinyl ester selected can remain as clear as possible, even after application and curing. Therefore, whilst it is not necessary that the vinyl ester resin remain as clear as the clear barrier gelcoat, a dark vinyl ester will have the effect of overpowering the effect of some colours and also of chips and particles and is therefore undesirable. The base vinyl ester is therefore preferably maintained as clear as possible, even after application and curing.
A non-limiting example of a vinyl ester that has been found to be suitable for application in the present invention is bisphenol-A epoxy vinyl ester resin, such as Cray Valley Epovia Kayak™ KRF-1001MV, which is a clear transparent liquid resin. Any suitable vinyl ester can be utilised, as long as it is able to provide excellent cure of the vinyl ester gelcoat and can enable the coexistence of the highly water and chemical resistant vinyl ester resin behind the clear barrier gelcoat.
Similarly to selection of the composition for the clear barrier gelcoat, it is envisaged that other products may also be suitable for use in the coloured gelcoat layer. Possible non-limiting examples are a selection of polyester, vinyl ester or terephthalate based resins or gelcoats that can incorporate pigments and/or texturising components, including any bisphenol-A epoxy vinyl ester resin, brominated epoxy vinyl ester resin, novolac epoxy vinyl ester resin or elastomer modified vinyl ester resin.
As with the iso-NPG, the selection of additives added to the vinyl ester is significant for imparting desired qualities to the overall surface composition. In order to maintain the near clear qualities of the vinyl ester, it is desirable to again avoid the use of cobalt octoate as a promoter. It is again preferred that mixed metal promoters be used, such as zinc octoate and potassium octoate. However, further examples of suitable additives include Shen Catalyst PC-6, dimethyl aniline, EFKA-2020 defoaming agent and styrene monomers. In applications where the final colour of the coloured layer is relatively dark, it may be appropriate to add cobalt octoate (6% and 8%).
A suitable thixotropic agent is also added to enable sprayability.
The present invention also includes a method of manufacture of a surface composition and manufacture of a FRP product, such as a swimming pool or spa pool. The method essentially comprises the application of a clear polyester gelcoat liquid, in this case, the clear high molecular weight iso-NPG, to the surface of a mould. The iso-NPG, containing additives as described above, is sprayed evenly onto the mould in a manner known to the art, achieving a minimal wet thickness of 0.65 mm. The cured gelcoat preferably achieves a minimum Barcol hardness of 35 within 24 hours of application. As such, the clear barrier layer is able to provide the durability and abrasion resistance to withstand normal daily use of a swimming pool, including the use of automatic pool cleaners and in the case especially of spa pools, to water temperatures of up to 41° C.
Once the iso-NPG has appropriately cured so as to form the clear barrier layer, the vinyl ester, in this case, bisphenol-A epoxy vinyl ester resin, with additives as described above, is sprayed onto the gelcoated mould to give the product its coloured and optionally, textured appearance. The vinyl ester is then also permitted to cure as required.
Further structural and chemical and/or corrosion barrier layers are added as required and as dictated by the specific intended use of the product. For example, in manufacture of a swimming pool or spa pool, further layers may comprise a further vinyl ester corrosion barrier to improve impact resistance and thermal insulation, an isophthalic corrosion and structural layer, fibreglass lamination and also further reinforcing layers. The cured finished product is released from the mould, trimmed and transported to its place of service.
The creation of a product, such as a swimming pool, with the surface composition of the present invention confers quality and resilience of product that has not yet been achieved in the art. The present surface composition provides a clear barrier layer or gelcoat that will not discolour or fail under the harmful effects of UV radiation, such as is experienced when the pool is situated outdoors and therefore exposed to long periods of sunlight, or the combination of water and chemicals. Further, this clear barrier layer provides such an increased degree of protection that the second coloured or decorative layer disposed beneath can last for even longer periods of time than previously possible without fade or discolouration of pigmentation. Importantly, the degree of protection conferred by the clear barrier layer is such that a wider range of pigments can be employed in the coloured layer. That is, organic pigments, which would otherwise be destroyed or compromised upon exposure particularly to UV and oxidising agents, can be included in the coloured gelcoat layer.
It is proposed that application of the surface composition according to the present invention in swimming pools and the like will permit manufacturers to offer consumers longer guarantee of product without risking themselves to paying for pool refurbishments and replacements. That is, the products will look better and retain their new and vibrant appearance for much longer periods of time.
The durability and resilience of the surface composition of the present invention is evidenced by experimental data, testing the resistance of the surface composition to chemical degradation, as set out below:

EXAMPLES

Example 1

Chlorine Discolouration Tests

A series of tests were conducted on panels of fibreglass reinforced plastic (FRP), manufactured using known manufacturing techniques, procedures and formulations, as applicable to FRP pool manufacture, in order to compare the effectiveness of a known surface composition, known to be well above industry standard, with the surface composition according to embodiments of the present invention.
A series of square panels, measuring approximately 200 mm×200 mm were cut from two variations of FRP with a known surface composition (control panels) and also from two variations of FRP having the surface composition of an embodiment of the present invention applied thereon. The variations are as recited in Table 1 below:

TABLE 1

Panel Types and Identification

Panel				Control
Code	Barrier Layer	Under Layer	Colour/Effect	or Test

PAC	isophthalic	bisphenol-A	“Paramount”	Test
	neopentyl	epoxy vinyl	(marblestone effect)
	glycol	ester resin
PBC	isophthalic	bisphenol-A	“Light sapphire blue”	Test
	neopentyl	epoxy vinyl	(light blue colour, no
	glycol	ester resin	textured effect)
PC	isophthalic	None	“paramount” (marble	Control
	neopentyl		stone effect)
	glycol
PD	isophthalic	None	“light sapphire blue”	Control
	neopentyl		(light blue colour, no
	glycol		textured effect)

Each panel was placed in a separate tank of water and a trichlorisocyanurate swimming pool disinfection tablet was placed in direct contact with the surface of each panel, with both panel and tablet being fully submerged in the water. The tablet was placed directly on each panel to simulate the effect of many years degradation and bleaching of a pool surface by water and disinfectant. The tablet in each tank was weighed down to prevent migration of the tablet across the surface of the panel due to the release of gases and surface interactions.
The water in each tank was emptied daily and replaced with clean fresh tap water to ensure that the chlorine residual in the test water was not excessively high and did not contribute to early fading of the panels. Upon drainage of the water, each panel was washed, photographed and inspected for signs of colour or surface degradation. After replacement of the water and panel in each tank, the same tablet was replaced in exactly the same location upon the panel surface. Each panel was checked after two hours to ensure that the tablet had not moved from its position.
This process was repeated daily for up to 7 days. The observed appearance of each panel is outlined in Table 2 below:

TABLE 2

Observed Results after Exposure to Chlorine Tablet

Day	Panel PAC	Panel PBC	Panel PC	Panel PD

1	Good appearance.	Very faint	Slight tablet outline	Distinct circle shape of
	Faint tablet outline	tablet outline	visible	tablet
2	Good. Slight	No change	Fair, with slight etched	Extremely faded and
	discolouration		surface	gelcoat surface etched
3	No visible change	—	No visible change	—
4	Slight discolouration	—	Tablet area fading &	—
			slight etched surface
5	Slight discolouration	—	Faded and significant	—
			etching of surface
6	—		Surface badly etched
7	—	—	Slightly more fading of	—
			colour

Panels PBC and PD were removed from the testing program after two days of exposure since panel PD (without the inventive surface composition) had faded and deteriorated beyond repair.
After the fifth day of exposure, panel PAC was removed, cleaned and finely sanded by mild, gentle rubbing of the surface (600 grit wet and dry). This action, which was almost effortless, caused immediate removal of the discolouration. The panel was then polished and returned to the testing process.
A further PAC panel was subjected to the testing process without any intermediate polishing or cleaning.
At the conclusion of the testing process, panel PC was examined, where it was established that the surface was significantly degraded, showing extreme pitting and oxidation of the surface in contact with the tablet. The degree of damage caused to the surface was such that it was irreparable and irreversible.
In contrast, panel PAC showed little change to the surface, other than slight staining from the chlorine (green colour of free available chlorine) and extremely slight surface pitting. No degradation of the actual pigmentation in the panel itself was observed. After mild abrasion with 600 grit wet and dry, the surface pitting and the majority of chlorine discolouration was removed.
The above results demonstrate the ability of the surface composition of the present invention to protect the integrity and colour of the overall structure from degradation by water and chemicals.

Example 2

Advanced Accelerated 80° C. Testing

Panels PAC and PBC as described in Example 1 were subjected to water resistance tests in accordance with “AS/NZS 1838-1994 Swimming pools—premoulded fibre-reinforced plastics—design and fabrication” Standards. This Standard requires that the panels are able to pass 30 days at 80° C. in accordance with the prescribed Degradation Rating (Table E1 from the Standard). Both panels were subjected to the required conditions and passed the test with exceptional results. There was no degradation of the surface and no osmotic blistering. After 75 days there was still no osmotic blistering visible and negligible internal surface degradation.
It is therefore clear that the surface composition of the present invention advantageously enables the manufacture of FRP swimming pools and spa pools that are essentially completely fade resistant, exceeding current industry standards, and which comply with AS/NZS 1838-1994 with regard to blister resistance, chemical resistance and hydrolytic stability.

Example 3

Product Testing for Weathering and Ultra Violet Resistance

Twelve separate panels were manufactured and tested using the ASTM G154-06 “Standard practice for operating fluorescent light apparatus for UV exposure of non-metallic materials”. Control panels manufactured as part of the same sample were also supplied for the purposes of comparison.
Tests were performed by the Polymer Testing Laboratory of the Chisholm Institute in Dandenong Victoria 3175, Australia which is a NATA approved laboratory.
Each panel was exposed to 4 hours of condensation at 50° C. followed by 8 hours of UV-A exposure at 60° C. This pattern was repeated for the duration of a 2000 hour test.
Each panel was given a different identification letter being panels G, H, I, J, K, L, M, N, O, P, Q and R.
Each panel was intrinsically different. Ten panels were manufactured using a surface composition according to an embodiment of the present invention and two panels were made from what may be considered to be industry best practice.
All twelve panels had varying amounts and/or utilised different ultra violet inhibitors and absorbers.
This particular aspect of the testing was undertaken to address which additives would impart a beneficial effect to the surface composition in relation to the following:

- a) Ability to be used within the resin matrix and be sprayable and not effect the rheology of the gel coat.
- b) Not inhibit the curing process.
- c) Not import any characteristic hue or discolouration to the clear gel coat.
- d) Not increase the aeration of the gel coat as minute or microscopic air bubbles in sufficient proliferation will cause cloudiness or milkiness in the gel coat.
- e) Not inhibit the barcol harshness of the gel coat thus reducing the abrasive resistance and overall durability of the product.
- f) Provide the optimum weathering resistance and UVA resistance after 2000 hours on ASTM G 154-06.
- g) To establish optimum additive concentrations.
- h) Establish the most suitable ratio of UV light absorbers to stabilizers with the gel coat.

The following additives were added to the clear gelcoat barrier layer applied to each panel:
CIBA TINUVIN™ 400
A liquid hydroxyphenyl-triazine (HPT) UV absorber.
CIBA TINUVIN™ 384-2
A liquid UV absorber of the hydroxyphenyl-benzotriazole class.
CIBA TINUVIN™ 123
A liquid HALS stabilizer based on hindered aminoether functionality.
The panels were set up and tested according to ASTM G 154-06 and evaluated after 500 hours, 1000 hours, 1500 hours and 2000 hours.
Table 3 summarises the colour, coatings, additives and results of tests on the twelve panels.

TABLE 3

Results of Weathering and Ultra Violet Testing

Results

TINUVIN ™ additives

500 hr

1000 hr

1500 hr

2000 hr

Barrier

Under

wt. %

Appear-

Panel

Colour

Layer

123

384-2

400

ance

Texture

ance

Texture

ance

Texture

ance

Texture

G

Stirling

Iso-

VE

0.33

0.67

No

Smooth

Slight

No

Slight

No

NPG

change

but

yellow

change

loss

change

increase

tinge

in

gloss

surface

friction

H

Stirling

Iso-

VE

0.50

1.00

No

Smooth

Slight

No

Slight

No

NPG

change

but

yellow

change

loss

change

increase

tinge

in

gloss

surface

friction

I

Stirling

Iso-

VE

0.67

1.33

No

Smooth

Slight

No

Slight

No

Slight

No

NPG

change

but

yellow

change

loss

change

cloudy

change

increase

tinge

in

appear-

in

gloss

ance

surface

friction

J

Stirling

Iso-

VE

0.33

0.67

No

Smooth

Slight

No

Slight

No

NPG

change

but

yellow

change

loss

change

increase

tinge

in

gloss

surface

friction

K

Stirling

Iso-

VE

0.5

1.00

No

Smooth

Slight

No

Slight

No

Slight

No

NPG

change

but

yellow

change

loss

change

cloudy

change

increase

tinge

in

appear-

in

gloss

ance

surface

friction

L

Stirling

Iso-

VE

0.67

1.33

No

Smooth

Slight

No

Slight

No

Slight

No

NPG

change

but

yellow

change

loss

change

cloudy

change

increase

tinge

in

appear-

in

gloss

ance

surface

friction

M

Light

Iso-

none

0.98

Pale,

Smooth

Paler,

Slightly

Signifi-

Rough

Signifi-

No

Sapphire

NPG

small

but

small

rough

cantly

with

cantly

change

Blue

white

increase

white

surface

paler

chalky

paler

dots

in

dots

residue

surface

friction

N

Baltic

Iso-

VE

0.67

1.33

No

Smooth

Slight

No

Slight

No

Cloudy

No

Blue

NPG

change

but

yellow

change

loss

change

appear-

change

increase

tinge

in

ance

in

gloss

surface

friction

O

Stirling

Iso-

VE

1.00

No

Smooth

Slight

No

Slight

No

Cloudy

No

NPG

change

but

yellow

change

loss

change

appear-

change

increase

tinge

in

ance

in

gloss

surface

friction

P

Stirling

Iso-

VE

0.75

No

Smooth

Slight

No

Slight

No

Cloudy

No

NPG

change

but

yellow

change

loss

change

appear-

change

increase

tinge

in

ance

in

gloss

surface

friction

Q

Stirling

Iso-

VE

0.5

No

Smooth

Slight

No

Slight

No

Loss

Slightly

NPG

change

but

yellow

change

loss

change

of

rough

increase

tinge

in

gloss/

in

gloss

cloudy

surface

appear-

friction

ance

R

Silver

Iso-

none

0.98

Dull

Smooth

Dull,

Slightly

Signifi-

Slightly

Signifi-

Rougher,

Mediter-

NPG

with

but

with

rough

cantly

rough

cantly

with

ranean

yellow

increase

yellow

surface

paler

with

paler

tinge

in

tinge

chalky

surface

residue

friction

Panels M and N were almost identical in colour

Panel R, of Silver Mediterranean colour was almost identical in colour to the Sterling panels.

The description “no change” indicates that there was no change in appearance of the panel from its original state or from the previous inspection

Iso-NPG = isophthalic neopentyl glycol

VE = bisphenol-A epoxy vinyl ester

As illustrated in FIGS. 3 to 14 the ten panels with the inventive composition clearly and significantly out performed the two comparative test panels M and R. The following conclusions can be made:

- 1. Panels M and R showed significant degradation to surface appearance and texture over the course of the tests.
- 2. The best performing panels were panels G, H, J and K. All showed only slight loss of gloss and a slight yellow tinge. An initial change in surface friction was evident across all panels however panels G, H, J and K all showed no change from the previous test indicating a very slight initial change followed by longer periods of stability and no further change.
- 3. The panels with higher concentrations of TINUVIN™ additives under performed those with lower concentrations of additives. Accordingly, panels with 1.5% additive outperformed panels with 2.0% additives
- 4. Panels with 2% additive rate showed a foggy/cloudy appearance.
- 5. The panels with the ratio of two parts absorber to one part stabilizer out performed the panels with one part absorber to one part stabilizer.
- 6. There were negligible differences between panels G, H and K.
- 7. Panel G outperformed panel J indicating that TINUVIN™ 400 offered superior performance to TINUVIN™ 384-2.

Panel H contained 1.5% additives in comparison to Panel G with 1%. As there were not any derogatory effects on Panel H after 2000 hours it was concluded that Panel H would in all probability out perform Panel G under the conditions of ASTM G154-06 for periods longer than 2000 hours.
Overall, it was concluded that the inventive composition offers the following major improvements and benefits over standard coatings particularly when combined with the advantageous characteristics of TINUVIN™ 400 and TINUVIN™ 123 absorbers and stabilizers.
The collective results indicate the following improvements and advantages may result from the use of the surface composition of the present invention.

- 1. A swimming pool that does not fade and which retains its vivid, brilliant colour for many, many years.
- 2. No bleach marks, yellowing or chalking.
- 3. The pool colour is separated from the bleaching effects of chlorine, bromine or other oxidants by application of the barrier layer.
- 4. Brilliant and lasting gloss finish that resists algae, staining and is easier to clean, resulting in less maintenance of the pool.
- 5. The aesthetic and structural laminates are fully protected from the aggressive nature of water.
- 6. Excellent inter-laminar adhesion, ensuring all the specific applications of the inventive coating composition and the swimming pool laminates are structurally, mechanically and chemically bonded together, giving the swimming pool greater strength, durability and blister resistance.
- 7. Improved hydrolytic stability.
- 8. Chances of “osmotic blistering” are dramatically minimized.
- 9. Resists degradation by UV light radiation and eliminates a tendency to crack from UV exposure. Has a high thermal stability and is suitable for extreme environmental conditions.

Whilst the surface composition of the present invention finds particular application in the manufacture of swimming pools and pool spas, it is equally applicable and useful for any product, particularly FRP product, which spends any significant period of time submerged in water and/or subjected to UV radiation.

Claims

1. A surface composition for reducing degradation and fading of surfaces subjected to extended periods of submersion in an aqueous liquid, the surface composition comprising at least one clear barrier layer and at least one under layer, wherein the clear barrier layer is in use, disposed atop the under layer and in contact with the aqueous liquid whereby the clear barrier layer protects the structure and appearance of the under layer.

2. The surface composition according to claim 1, wherein the under layer is a decorative layer comprising one or more decorative or ornamental agents.

3. The surface composition according to claim 1, wherein the composition comprises one or more UV inhibitors, absorbers or stabilisers.

4. The surface composition according to claim 1, wherein the clear barrier layer comprises one or more UV inhibitors, absorbers or stabilisers.

5. The surface composition according to claim 1, wherein the clear barrier layer is a clear polyester gelcoat.

6. The surface composition according to claim 5, wherein the clear polyester gelcoat comprises one or more phthalate containing polyesters, vinyl containing polyesters or methyl methacrylate containing polyesters.

7. The surface composition according to claim 6, wherein the clear polyester gelcoat comprises a phthalate containing polyester.

8. The surface composition according to claim 7, wherein the clear polyester gelcoat is derived from an isophthalic neopentyl glycol.

9. The surface composition according to claim 8, wherein the clear polyester gelcoat is derived from greater than 70 mole % neopentyl glycol based on the total mole % of dihydroxy compounds in the polyester.

10. The surface composition according to claim 3, wherein the barrier layer comprises a triazine based UV absorber.

11. The surface composition according to claim 3, wherein the barrier layer comprises a hindered amine light stabiliser.

12. The surface composition according to claim 1, wherein the barrier layer comprises one or more metal promoters.

13. The surface composition according to claim 1, wherein the one or more metal promoters is selected from the group consisting of zinc octoate, potassium octoate or cobalt octoate.

14. The surface composition according to claim 1, wherein the under layer comprises one or more polyesters, vinyl esters or terephthalate based resins.

15. The surface composition according to claim 14, wherein the under layer comprises one or more epoxy vinyl esters, brominated epoxy vinyl esters, novolac epoxy vinyl ester resins or elastomer modified vinyl ester resins.

16. The surface composition according to claim 15, wherein the epoxy vinyl ester resin comprises a bisphenol-A epoxy vinyl ester resin.

17. The surface composition according to claim 1, wherein the under layer comprises one or more metal promoters.

18. A method of manufacturing a surface composition, the method comprising applying a clear gel coat liquid to a mould, permitting the gelcoat to cure and subsequently applying a coloured or decorative vinyl ester layer to the cured gelcoat.

19. The method according to claim 18, wherein the clear gel coat is derived from an isophthalic neopentyl glycol.

20. The method according to claim 18, wherein the vinyl ester layer comprises a bisphenol-A epoxy vinyl ester resin.

21. (canceled)

22. A pool, the pool having a surface composition comprised of at least one clear barrier layer and at least one under layer, wherein the clear barrier is in use, disposed atop the under layer and in contact with liquid in the pool, whereby the clear barrier layer protects the under layer from degradation.