GB2171008A

GB2171008A - Baths

Info

Publication number: GB2171008A
Application number: GB08503628A
Authority: GB
Inventors: Neil Howard Pullman
Original assignee: LACONITE PLASTICS Ltd
Current assignee: LACONITE PLASTICS Ltd
Priority date: 1985-02-13
Filing date: 1985-02-13
Publication date: 1986-08-20
Also published as: GB8503628D0; GB2171008B

Abstract

A bath made of plastics material consists of an inner layer 1 of plastics material defining an inner surface of the bath and an outer layer 2 of a sheet material which together with the inner layer 1 defines a cavity of a desired shape, the cavity being filled by a substantially rigid foamed plastics material 3. The cavity may be shaped in any desired way to give greater thickness of the rigid foamed plastics material 3 where the inner layer 1 is of lesser thickness as a result of any moulding operation or where the inner layer 1 will support the greatest weight. The outer layer 2 may be shaped to give a desired visual appearance to the bath or to provide a functional support such as a continuous plinth or legs at the foot of the bath. <IMAGE>

Description

SPECIFICATION Baths This invention relates to baths and particularly to baths made of plastics materials.

Broadly speaking, there are two methods of making plastic baths. In one method a sheet of plastics material, commonly an acrylic material such as polymethylmethacrylate, is moulded to the required shape for the bath and the outer surface of the moulded shape is then sprayed with a mixture of polyester resin and glass fibre to form a layer which, when cured, provides the necessary strength for the bath. When the bath shape is moulded from relatively thin plastic sheets of 3mm or 5 mm thickness, the whole of the outer surface of the bath is sprayed with the glass fibre reinforced plastic, but if a thicker sheet, for example a sheet of 8 mm thickness, is used, only the lower part of the bath, where the sheet has been substantially reduced in thickness as a result of the moulding process, need be reinforced.In either case a further reinforcement is provided by sticking a sheet of chipboard to the underside of the floor of the bath, the chipboard being preferably adhered by pressing it to the glass fibre reinforced polyester resin while the resin is in the process of curing.

In this first method there is the necessity to apply the reinforcing layer of polyester and glass fibre which is done by hand and which is generally uneconomic as there is a tendency to use greater quantities of materials than are strictly necessary, in order to ensure that the necessary strength is imparted to the moulded plastics sheet.

In another method of making a plastic bath, the bath is formed from a composite sheet of material comprising a thin layer of acrylic adhered to a much thicker layer of acrylonitrile butadiene styrene (ABS). The composite sheet used is approximately 10 mm in thickness, of which the acrylic layer constitutes 1 mm or less. The bath is then moulded, for example by vacuum forming, from the composite sheet material to form a bath of which the inner surface is constituted by the acrylic layer. The plastic bath formed in this way is reasonably strong but liable to distortion when subjected to the weight of a human body.

The plastic baths made by both the above methods further include a reinforcing rectangular frame affixed beneath the rim of the bath in order to provide the necessary strength.

This reinforcing frame has to be applied as an additional step following the steps of the two methods described above.

It is an object of the present invention to provide a bath having a surface of plastics material which is of simpler construction and does not involve the necessity to include a rectangular wooden reinforcing frame.

According to the present invention there is provided a bath comprising an inner layer of plastics material, an outer layer of a sheet material, and a substantially rigid foamed plastics material adhered to both the outer surface of the inner layer and the inner surface of the outer layer and substantially filling the space between said surfaces.

The substantially rigid foamed plastics material filling the space between the inner layer of plastics material and the outer layer of sheet material provides stiffness to the bath shape as a whole with minimum additional weight.

The space between the inner layer of plastics material and the outer layer of sheet material may vary in thickness in order to provide for a greater thickness of the rigid foamed plastics material at portions of the bath where the plastics material is thinner as a result of being stretched in the moulding operation to form the essential bath shape. The thickness of the space may also be increased to provide any desired shaping of the exterior defined the outer layer of sheet material, and in particular to provide a supporting member or members such as a continuous plinth or legs at the foot of the bath.

Although it is preferred to use such a quantity of rigid foamed plastics material as to avoid the necessity for any additional reinforcing member,nevertheless the bath according to the present invention may include a reinforcing member, for example a piece of chipboard, within the foamed plastics material if desired.

The substantially rigid foamed plastics material may be a body consisting of the foamed plastics material, for example a rigid foamed polyurethane,a foamed polyester resin, or a foamed phenolic formaldehyde resin. Alternatively, however, the substantially rigid foamed plastics material may consist of pre-expanded beads of a plastics material such as polystyrene in an adhesive binder uniting the inner layer of plastics material to the outer layer of sheet material in a rigid structure.

The outer layer of sheet material may be a rigid or semi-rigid material, for example a moulded polystyrene sheet. In using the term "semi-rigid" in this context it is intended to denote that the material of the rigid sheet is modified by the inclusion of a small percentage of a resilient material, for example 5-7% of latex rubber,in order to render the rigid material less liable to becoming cracked as a result of accidental impact.

The outer layer may however also comprise a woven cloth sheet or, in cases where the bath is designed to be freestanding without any additional decorative features, such as bath panels, the outer layer may comprise plastics material similarly tinted to the plastics material forming the inner layer and the water containing surface of the bath.

The inner layer of plastics material may con sist of a layer of polymethylmethacrylate or it may comprise a moulded acrylonitrile butadiene styrene sheet having a surface layer of polymethylmethacrylate.

According to another aspect of the present invention there is provided a method of manufacturing a bath comprising the steps of moulding a sheet of plastics material to the shape desired for the interior surface of the bath, defining a cavity of a desired shape adjacent the external surface of the moulded plastics sheet, and uniting the outer surface of the moulded plastics sheet to the inner surface of the layer of material defining the outer wall of the cavity by means including a rigid foamed plastics material.

The outer surface of the moulded plastics sheet may be united to the inner surface of the layer of material by forming a foamed plastics material within the cavity and causing the foamed plastics material to set and adhere to both the said outer surface and the said inner surface, or by introducing pre-expanded beads, for example of polystyrene, into the cavity and then filling the cavity with adhesive which is caused to set and adhere to both the said outer surface and the said inner surface as well as to the pre-expanded beads.

The present invention will be further understood from the following description of embodiments thereof which is made, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a transverse cross-sectional view of a first bath shape in accordance with the present invention, and Figure 2 is a transverse cross-sectional view through a modified bath shape in which a supporting plinth is formed integrally with the bath.

Referring first to Figure 1, there is shown a bath comprising an inner layer 1 of a plastics material joined to an outer layer 2 of a sheet material with the space between the inner layer 1 and the outer layer 2 filled by a rigid foamed plastics material 3. The thickness of the rigid foamed plastics material 3 is greater at the base of the bath where the inner layer 1 of plastics material is thinner as a result of being stretched during moulding of the plastics material to the bath shape.

The bath of Figure 1 will need to have a separate support structure when the bath is installed. However, in Figure 2 there is shown a design of bath in accordance with the present invention which does not require a separate support structure.

Referring now to Figure 2 the bath is again constructed of an inner layer 4 of plastics material, an outer layer 5 of sheet material with a rigid foamed plastics material 6 filling the space between the inner layer 4 and the outer layer 5. The rigid foamed plastics material 6 is bonded to the outer surface of the inner layer 4 and the inner surface of the outer layer 5.

However, in the embodiment of Figure 2 the sheet material forming the outer layer 2 is shaped so as to provide a continuous supporting plinth 7 on which the whole bath structure stands with the rigid foamed plastics material 6 providing all the necessary strength for the bath.

As shown in the accompanying drawings the distance between the inner layer 1 or 4 of plastics material and the outer layer 2 or 5 of sheet material is variable. The distance between these layers may vary from 5 to 25 mm in thickness or may at some points be as much as 100 mm in thickness. In every case however, the space between the layers is substantially filled by the rigid foamed plastics material 3 or 6 in order to provide the strength for the bath.

As already indicated the materials for the inner layer and the outer layer and for the rigid foamed plastics material may be selected from a fairly wide range of known materials.

Some examples of specific combinations are given below: 1. A layer of polymethylmethacrylate (PMMA) to provide an internal decorative (i.e.

coloured) surface with an outer layer of polystyrene sheet, andthe foamed layer consisting of rigid polyurethane.

2. An acrylonitrile Butadiene Styrene (ABS) sheet coextruded with a surface layer of PMMA for the internal decorative surface with an outer layer of woven glass cloth, the foamed layer consisting of expanded polyester resins.

3. A bath consisting of gel coat (for example PMMA) and a thin layer of polyester resin reinforced with fibre glass for the decorative internal layer with an external layer formed on the same mould as used for the decorative layer in polystyrene sheet, and with the foamed layer consisting of pre-expanded polystyrene spheres or beads bonded with adhesive to give stiffness and insulation to the whole bath.

4. A bath consisting of a PMMA inner layer and a similar layer of PMMA forming an outer layer shaped to provide a supporting plinth as in Figure 2 with the rigid foamed layer consisting of rigid polyurethane.

In addition to providing the essential strength for the structure of the plastic bath the rigid foamed plastics material also provides some insulation preventing heat loss through the walls of the bath during use thereof.

In this Application the term "foamed plastics material" is used to mean not only the products obtained by the use of one or more gas-producing chemicals (foaming agents) in a molten plastics material, but also a product formed by including gas-filled objects in a molten plastics material. The gas-filled objects may be gas-filled glass spheres, an expanded mineral substance such as perlite, or pre-ex panded spheres of plastics material.

When gas-filled spheres are used these are preferably bonded with an epoxy resin adhesive, which is the molten plastics material in which thespheres are dispersed before the plastics material is cured to form the rigid structure.

Claims

1. A bath comprising an inner layer of plastics material, an outer layer of a sheet material, and a substantially rigid foamed plastics material adhered to both the outer surface of the inner layer and the inner surface of the outer layer and substantially filling the space between said surfaces.

2. A bath according to Claim 1, wherein the foamed plastics material is of different thicknesses at different parts of the bath.

3. A bath according to Claim 1 or Claim 2, wherein the outer layer is shaped to form a supporting member or members for the bath.

4. A bath according to any one of Claims 1 to 3, wherein a reinforcing support member is included within the foamed plastics material.

5. A bath according to any one of Claims 1 to 4, wherein the foamed plastics material comprises pre-expanded beads of plastics material in a cured resin binder.

6. A bath according to any one of Claims 1 to 4, wherein the outer layer comprises a rigid or semi-rigid material.

7. A bath according to any one of Claims 1 to 5, wherein the outer layer comprises plastics material.

8. A bath according to any one of Claims 1 to 5, wherein the inner layer comprises a layer of polymethylmethacrylate.

9. A bath according to any one of Claims 1 to 5, wherein the inner layer comprises a moulded acrylonitrile butadiene styrene sheet having a surface layer of polymethylmethacrylate.

10. A bath according to any one of Claims 1 to 5, 8 and 9, wherein the outer layer comprises a moulded polystyrene sheet.

11. A bath according to any one of Claims 1 to 5, 8 and 9, wherein the outer layer comprises a woven glass cloth.

12. A bath according to any one of Claims 1 to 4, wherein the foamed plastics material comprises rigid foamed polyurethane.

13. A bath according to any one of Claims 1 to 4, wherein the foamed plastics material comprises foamed polyester resin material.

14. A bath according to any one of Claims 1 to 11, wherein the foamed plastics material comprises pre-expanded beads of polystyrene adhered to one another and to both the said outer surface and the said inner surface by an adhesive binder.

15. A bath substantially as hereinbefore described with reference to the accompanying drawings.

16. A method of manufacturing a bath comprising the steps of moulding a sheet of plastics material to the shape desired for the interior surface of the bath, defining a cavity of a desired shape adjacent the external surface of the moulded plastics sheet, and uniting the outer surface of the moulded plastics sheet to the inner surface of a layer of material defining the outer wall of the cavity by means including a rigid foamed plastics material.

17. A method according to Claim 16, wherein the outer surface of the moulded plastics sheet is united to the inner surface of the layer of material by forming a foamed plastics material within the cavity and causing the foamed plastics material to set and adhere to both the said outer surface and the said inner surface.

18. A method according to Claim 16, wherein the outer surface of the moulded plastics sheet is united to the inner surface of the layer of material by an adhesive containing pre-expanded beads of polystyrene.

19. A method of manufacturing a bath substantially as hereinbefore described with reference to the accompanying drawings.