Patent Application
20140317839
The present invention relates to coping elements, in particular to coping elements used around the edge of a swimming pool.
Conventional coping elements installed around the edge of swimming pools are made from materials such as stone, concrete and reconstituted stone. Such coping stones are often formed with a bull nose or rounded exposed edge so that corners are eliminated from their profile in order to minimise the danger associated therewith. However, such coping elements remain hazardous, since if a user of the swimming pool was to slip or misjudge his entry into the water, he could collide with the coping stone and receive an injury, potentially a serious injury.
It is known from WO2009050426 to provide coping elements having multiple portions. WO2009050426 discloses an arrangement in which the different portions are provided with interlocking means, to allow them to be secured together. However, the provision of interlocking components (e.g. protrusions or depressions at the surface of a first portion for mating with a corresponding depression or protrusion provided on the surface of a second portion) is time-consuming and increases the cost of manufacture.
Thus, it is an aim of the present invention to provide an improved method for joining the different portions of a coping element.
Therefore, at its most general, the present invention may provide a method of manufacturing a swimming pool coping element in which an outer layer portion and an infill portion are joined using pressure sensitive adhesive.
In a first aspect, the present invention may provide a method of manufacturing a swimming pool safety coping element comprising an outer layer portion and an infill portion, the outer layer portion at least partly bounding the infill portion, the method comprising the steps of:
Effectively, the method of the first aspect of the invention provides a coping element having at least two portions: the outer layer portion effectively providing a skin, having e.g. non-slip properties, while the infill portion provides the bulk mechanical properties required by the application, e.g. resilience, so as to reduce the possibility of injury arising from any collision with the coping element.
By Low Surface Energy is meant a material having a surface energy below 30 dynes/cm (0.03 Nm), preferably below 25 dynes/cm (0.025 Nm), most preferably below 23 dynes/cm (0.023 Nm). The Low Surface Energy material may comprise at least one of the following compounds: silicone, ethylene vinyl acetate, and/or a block copolymer. A suitable block copolymer may be Evoprene™. Preferably, the Low Surface Energy material comprises heat-cured silicone rubber.
The outer layer portion may be formed through e.g. pressing, extrusion, or injection moulding. This may be followed by a curing step, at a temperature of e.g. 130-180° C. Additionally, materials having luminescent properties may be embedded in the outer layer portion. Suitable materials may comprise phosphors such as strontium aluminate or zinc sulphide. The luminescent material may help to define the edge of the swimming pool in conditions of low ambient light.
The provision of a Low Surface Energy material may help to ensure that the coping element is not easily wet by water e.g. from the swimming pool. Thus, by providing a coping element having a Low Surface Energy outer layer portion, it may be possible to reduce the risk of slippage on the coping element.
It has been found that Low Surface Energy materials are not easily bonded to other materials, e.g. materials typically used for the infill portion. Surprisingly, it has been found that this problem may be at least partly alleviated by applying pressure sensitive adhesive across a first surface of the outer layer portion, whereby this surface then receives the flowable polymer composition that provides the infill portion.
Preferably, the first surface of the outer layer portion is cleaned using an organic solvent, before the pressure sensitive adhesive is applied. Typically, this cleaning step is carried out using an organic solvent, such as an aromatic hydrocarbon. In a preferred example, the organic solvent may be xylene.
As is well-known in the art, a pressure sensitive adhesive is an adhesive that forms a bond when pressure is applied between the adhesive and a contacting surface. Typically, no solvent, water, or heat is needed to activate the adhesive.
The pressure sensitive adhesive generally comprises an elastomer mixed with a suitable tackifier. The elastomer may be e.g. silicone rubber. The tackifier may be e.g. a silicate resin.
The pressure sensitive adhesive may be applied e.g. by brushing, painting, or spraying.
Typically, the flowable polymer composition is prepared from at least one of the following materials: vegetable oil, urethane, epoxy, latex, block copolymer, polyethylene foam, and/or polypropylene foam. A suitable vegetable oil is castor oil.
In a preferred example of the method, the flowable polymer composition is prepared from castor oil and a further polyol as starting materials. In a particularly preferred example, the further polyol is a polyether polyol. It is also preferred that the further polyol is ethylene oxide tipped. The molecular weight of the further polyol is preferably at least 3000, more preferably at least 6000.
It is possible (although less preferred) that the further polyol is a polyester polyol. Furthermore, in less preferred examples, the further polyol may be tipped with a different alkylene oxide, for example, propylene oxide.
Generally, castor oil and/or the further polyol may be mixed with an isocyanate compound, resulting in a polyurethane blend that, on setting, may provide the infill portion. Effectively, the isocyanate compound may be considered to function as a hardener for the polyol mixture.
Typically, the polyol mixture comprises equal parts by weight of castor oil and the further polyol.
Typically, the infill portion comprises a filler, such as rubber crumb.
The step of allowing the polymer composition to set may be carried out at ambient temperature. Alternatively, higher temperatures may be used (e.g. 50-60° C.), to decrease setting time.
In a second aspect, the present invention may provide: a swimming pool safety coping element comprising an outer layer portion and an infill portion, the outer layer portion at least partly bounding the infill portion, wherein:
The outer layer portion, the infill portion, and the layer of pressure sensitive adhesive of the coping element according to the second aspect of the invention may comprise one or more preferred features of the corresponding elements of the first aspect of the invention.
The invention will now be described by way of example with reference to the following FIGURE in which:
Referring to
The skin 12 is prepared using silicone rubber, which is pressed and heat-cured to provide the shape shown in
The pressure sensitive adhesive 16 is polydimethylsiloxane rubber, mixed with a silicate resin tackifier.
The skin 12 is prepared for the application of the pressure sensitive adhesive by cleaning the surface to which the PSA is to be applied, using a xylene solvent. The solvent is then allowed to evaporate. After this stage, the PSA is painted on to the cleaned surface and allowed to rest until it becomes tacky.
After this, a flowable polymer composition is poured onto the PSA-coated surface of the skin 12, and allowed to set, to provide the infill portion 14.
The flowable polymer composition is made by blending the following components:
Optionally, 8 parts by weight of a molecular sieve may be added (e.g. zeolite) and 5 parts by weight TiO2.
This blend is then mixed with an isocyanate polymer and allowed to react at ambient temperature and pressure, to provide a flowable polyurethane composition for pouring over the PSA-coated surface of the skin 12. The castor oil, the polyether polyol, and isocyanate polymer are mixed in stoichiometric amounts to provide a polyurethane blend, as is known in the art. For example, 21 parts by weight isocyanate polymer may be added to a blend comprising 50 parts by weight castor oil and 50 parts by weight of the polyether polyol.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1103259.6 | Feb 2011 | GB | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/GB12/50419 | 2/24/2012 | WO | 00 | 10/22/2013 |
