GB2402363A

GB2402363A - Moulded shower trays

Info

Publication number: GB2402363A
Application number: GB0310496A
Authority: GB
Inventors: David Grooms; Ken Grooms
Original assignee: ESL HEALTHCARE Ltd
Current assignee: ESL HEALTHCARE Ltd
Priority date: 2003-05-07
Filing date: 2003-05-07
Publication date: 2004-12-08
Also published as: GB0310496D0

Abstract

The present invention relates to shower trays, in particular to shower trays which are of a low height, and to processes for the production therefor. A process is disclosed to enable a low height shower tray 10 to be constructed with the strength to handle wheelchair access, obese people, low floor height or level access and achieve tray sizes in excess of the standard 1000 x 1000 tray available on the domestic market. The process includes the steps of i) applying a curable resin to the interior surface of a shower tray mould; ii) allowing the resin to at least partially cure; iii) applying a glass fibre mat to the resin layer, the mat being impregnated with a curable resin; iv) applying a dry layer of glass fibre mat to the mould such that a void is formed between the impregnated glass fibre mat and the dry layer glass fibre mat; v) forming an inlet aperture and at least one vent in the dry layer glass fibre mat; and vi) filling the void with a hardenable form material. A shower tray obtained by the process is also disclosed and comprises a hardened foamed core 14 with a dry layer of glass fibre mat 13 on a lower surface thereof and a resin impregnated glass fibre mat 12 on a top surface.

Description

1 2402363

SHOWER TRAY

The present invention relates to shower trays, in particular to shower trays which are of a low height, and to processes for the production therefor. s

Traditional shower trays are generally created from thernoformed plastics or glass reinforced plastics (GRP) supported by foam, resin and filler mixes or layers of GRP with or without timber or foam support.

When constructing a low floor height tray it becomes difficult to create strength and guarantee that the tray will remain straight. These trays are often sold for use by the disabled or less able population and therefore are much longer and wider than normal shower trays. Additionally, users are often wheelchair-bound adding to the weight supporting requirements of such trays. These requirements further increase the production problems when trying to achieve a low height without bowing.

The trays are often constructed from GRP to enable strength to be created over a large area with very little wall height. This process is labour intensive, expensive and has a tendency to bow. Shower trays of this type are often reinforced with sheet material such as foam or wood to add strength and keep the tray level.

Using materials such as polyurethane foam to fill the voids adds strength but creates stresses on the GRP which leads to the tray mix-shaping.

Accordingly, there is a need for an improved process to enable a low height shower tray to be constructed cheaply with the strength to handle wheelchair access, obese people, low floor height or level access and achieve tray sizes in excess of the standard 1000 x 1000 tray available on the domestic market.

In a first aspect, the present invention provides a process for the manufacture of a shower tray, the process comprising: i) applying a curable resin to the interior surface of a shower tray mould; ii) allowing the resin to at least partially cure; iii) applying a glass fibre mat to the resin layer, the mat being impregnated with a curable resin; iv) applying a dry layer of glass fibre mat to the mould such that a void is formed between the impregnated glass fibre mat and the dry layer glass fibre mat; v) forming an inlet aperture and at least one vent in the dry layer glass fibre mat; and vi) filling the void with a hardenable foam material.

Preferably, the curable resin is a polyester resin, more preferably an unsaturated polyester resin.

Preferably the curable resin has a gel coat formulation allowing hand or spray-gun application.

Preferably, the resin includes an anti-bacterial composition.

Preferably, the hardenable foam material is a polyurethane foam, more preferably a medium density polyurethane foam.

Preferably, the glass fibre mat is a chopped strand glass fibre mat.

In a second aspect, the present invention also provides a shower tray obtainable by the above method. The shower tray comprises a hardened foamed core having a cured resin-impregnated glass-fibre mat applied to an upper surface thereof, the resin impregnated mat having a cured resin layer applied thereto; the core further having a dry-layer glass fibre mat applied to a lower surface thereof The above and other aspect of the present invention will now be explained in further detail with reference to the following example.

Figure 1 shows a sectional view of an embodiment of a shower tray in accordance with the present invention; and Figure 2 is a schematic sectional view of the tray of Figure 1.

A shower tray 10 is produced using a mould manufactured to the desired dimensions and shape. An unsaturated polyester resin gel coat is applied by hand or with a spray B to form an outerskin. The gel coat m y also contain an anti-bacterial agent. Once the gel has started to cure a single layer of chopped strand glass fibre mat 12 is applied using an unsaturated polyester resin to wet it out.

A base for the tray is then prepared which has a dry layer of chopped strand glass fibre mat 13 attached by tags, clips or double sided tape forming a void between the base and the impregnated glass-fibre mat. A mould top is placed on top of the bottom mould and secured. In the centre or the side of the top mould is a hole where medium density polyurethane foam is poured into the void. The foam expands and air is vented through a number of breather holes placed in the top of the mould. Once the foam has hardened 14 the mould sections are separated and the finished tray is removed. The foam impregnates the dry layer glass-fibre mat binding the mat to the tray.

We will now give more details of certain components of a preferred embodiment Resin Manufacturer: Cray Valley Product: Unsaturated polyester resin gel coat The gel coat is a specially formulated polyester resin with thixotropic agents and pigments to give the desired colour and finish. A catalyst (MEK Peroxide) is added to the resin to allow the polyester to cure.

The gel coat can be hand brushed or sprayed onto the mould (contact moulding). This provides the top surface of the shower tray. The gel coat has no structural strength and needs backing with fibreglass and polymer resin laminates. When the part is removed from the mould the gel coat will be the exterior side of the part. Polyesters will shrink approximately 6 to 9% by volume. This shrinkage will cause the products to bow or misshape if different shrinkage rates are present in the different layers.

Glass Fibre Laminate Manufacturer: Cray Valley Product: Unsaturated polyester resin chopped glass mat Alter the gel coat has been applied and cured, it is reinforced (laminated) by bonding a glass fibre mat with a polyester laminating resin to the gel coat for structural strength. The glass fibre mat is wetted out with the resin. Using brushes and rollers the fibreglass is fully impregnated with the resin and any air bubbles are removed.

Care is taken to ensure that only the required amount of resin is used to avoid any excess, which will decrease the strength and create uneven shrinkage.

Polyurethane Foam Manufacturer: Trident Foams Product: Tripor 217 The polyurethane foam is a 2 part liquid. The mould is closed. The 2 parts of the foam are mixed together and poured into a hole on the top of the closed mould. The mixture expands and exhausts air through vent holes. The foam composition then sets to create a solid foam block to the shape of the void.

Glass Fibre Mat Backing The above layers suffer from different shrinkage rates. To overcome this a sheet of glass fibre mat is placed onto the top mould by double sided tape or tags. The foam impregnates the glass fibre mat making it part of the foam core. The strength of the foam and this glass fibre mat restricts the tendency to bow with the shrinkage.

This manufacturing process enables the production of a thin tray that remains straight.

No longer are multiple layers of glass fibre needed to create strength. No sheet support product is needed such as wood to gain the rigidity required. By using a dry sheet of GRP matting on the top mould we eliminate all the bowing that usually results from use of GRP and polyurethane foam.

Claims

CLAIMS: 1. A process for the manufacture of a shower tray, the process

comprising: i) applying a curable resin to the interior surface of a shower tray mould; ii) allowing the resin to at least partially cure; iii) applying a glass fibre mat to the resin layer, the mat being impregnated with a curable resin; iv) applying a dry layer of glass fibre mat to the mould such that a void is formed between the impregnated glass fibre mat and the dry layer glass fibre mat; v) forming an inlet aperture and at least one vent in the dry layer glass fibre mat; and vi) filling the void with a hardenable form material.
2. A process claimed in claim 1, wherein the curable resin is a polyester resin.
3. A process as claimed in claim 2, wherein the curable resin is an unsaturated polyester resin.
4. A process claimed in any one of the claims 1 to 3, wherein the curable resin has a gel coat formulation allowing hand or spray-gun application.
5. A process claimed in any one of the claims 1 to 4 wherein the resin includes an anti-bacterial composition.
6. A process as claimed in any one of the claims 1 to 5, wherein the hardenable foam material is a polyurethane foam.
7. A process as claimed in claim 6, wherein the polyurethane foam is a medium density polyurethane foam.
8. A process as claimed in claims 1 to 7, wherein preferably, the glass fibre mat is a chopped strand glass fibre mat.
9. A shower tray obtainable by the above method, and comprising a hardened foamed core having a cured resin-impregnated glass-fibre applied to an upper surface thereof, the resin impregnated mat having a cured resin layer applied thereto; the core further having a dry-layer glass fibre mat applied to a lower surface thereof.