NZ329586A - A thermally insulated tub comprises fibreglass reinforced resinous material surface layer and a core of settable polyurethane foam - Google Patents

Abstract

Tub 10 has inner shell 12 nested within outer shell 14. The shells form a cavity filled with a settable foam plastic which bonds the shells.

Description

NEW ZEALAND PATENTS ACT, 1953 No: 329586 Date: 15 January 1998 COMPLETE SPECIFICATION A THERMALLY INSULATED TUB We, COLONIAL BATHS NZ LIMITED, a New Zealand company, of 7/35 Guthrie Street, Lower Hutt, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: INTELLECTUAL PROPERTY OFFICE OFN.Z. "1" 1 5 JAN 1999 RECEIVED The present invention relates to a thermally insulated tub and to a method of making such a tub. In the preferred embodiment of the invention, the tub is a bath-tub. In the most preferred embodiment of the invention, the bath-tub is a free-standing bath-tub where usually both the inner and outer surfaces of the bath-tub will be visible.

In the specification, tubs are described as having a concave inner surface and a convex outer surface. The words "concave" and "convex" are used in a general sense referring to the general shape of a tub. While the inner and outer surfaces of the tub may be continuously curved, that is not an essential requirement of the invention. Therefore, tubs within the ambit of this invention may have straight sides and a flat bottom in cross-section. In this case, the connection of a side with the bottom may be by a curved portion though again that is not an necessary requirement of the present invention.

So-called "old fashioned" bath-tubs were usually made from cast iron, that is, iron or steel cast to the required shape. Modern bath tubs may also be made of cast iron but are usually made from pressed steel or from a sheet of a suitable plastics material which is moulded to shape, for example, either by vacuum or injection moulding. These bath-tubs comprise a single layer of material, either metal or plastics material. In the case of metal bathtubs the relatively high-thermal conductivity of the metal contributes to a relatively high rate of heat loss from hot water contained in the bath-tub in use. This can even be a problem with bath-tubs made from plastics materials even though plastics materials have lower coefficients of thermal conductivity than metals. Another problem that can be encountered with plastics bath-tubs is that they may flex slightly under the weight of a user and therefore may not give the same sense of solidity and stability to the user as metal bath-tubs.

In this specification, unless the context requires otherwise, the term "plastics material" includes settable resinous materials, such as those commonly used in fibreglass reinforced resins, such as epoxy resins, for example. When a fibreglass reinforced resin is applied to a mould, for example, by spraying, the resulting layer of material that is formed has one smooth surface, that being the surface in contact with the mould, that assuming that the mould itself has a smooth surface, but the other surface of the layer is somewhat uneven. A single layer of fibreglass reinforced resin is therefore not entirely satisfactory for use in making a freestanding bath-tub in that while the inside surface of the bath-tub may be a smooth surface, the outside of the bath-tub, which is also visible, is not such a smooth surface, that detracting from the aesthetic appearance of the bath-tub.

It was with problems such as these in mind that the present invention was devised.

In a first aspect, the present invention broadly consists in a method of making a thermally insulated tub having plastics foam-filled cavity between inner and outer shells of plastics material, the method requiring at least the steps of: applying a plastics material to a female mould having a smooth concave inner surface to form the outer shell of the tub having a smooth convex outer surface; applying a plastics material to a male mould having a smooth convex outer surface to form the inner shell of the tub having a smooth concave inner surface; nesting the inner shell in the outer shell, the inner shell generally having smaller dimensions than those of the outer shell whereby the inner shell is nested substantially entirely within the outer shell with a substantial portion of the inner shell spaced from the outer shell to provide said cavity between them; injecting a settable plastics foam material into the cavity to foam within and substantially fill the cavity and to bond with the shells to make a unitary tub having the smooth concave inner surface of the inner shell on the inside of the tub and the smooth convex outer surface of the outer shell on the outside of the tub.

The exposed surfaces of the tub are smooth in appearance and to touch. To enhance the smoothness a gel coat is preferably applied to each mould, preferably by spraying, before the plastics material is applied to that mould. The gel coat will usually be coloured. The colour may be white. Different colours may be used for the inside and the outside of the tub.

The plastics material is preferably a fibreglass reinforced resinous material. It is preferably applied to the moulds by spraying. After the plastics material has been sprayed onto a respective mould, the exposed surface of the shell thus formed may be evened out before the plastics material has set.

When the inner shell is nested within the outer shell the two shells are preferably joined together, and are more preferably sealed together, substantially about their respective peripheral edges. It is preferred that each of the moulds has an outwardly directed flange substantially about its peripheral edge so that each shell formed by a respective mould also has an outwardly directed flange substantially about its peripheral edge. The shells are preferably joined or sealed together by their flanges.

When the shells are nested together, the cavity is preferably provided between substantially the whole of the inner and outer shells except where they are joined together.

The preferred plastics foam material used to provide a core filling the cavity is a polyurethane foam material. Preferably the plastics foam material is injected into the cavity through a plurality of apertures in the outer shell and following foaming any surplus foam expressed back through the apertures is removed and at least one of the apertures is sealed. Preferably one of the other apertures is not sealed, that aperture being used, together with an aligned aperture provided in the inner shell, to receive a drain hole fitting.

The shells may be removed from their moulds prior to being nested together. Alternatively, it is preferred that the shells remain mounted to their moulds when they are nested together, and during foaming of the cavity the moulds are clamped together and released and removed from the shells only after the foam filling the cavity has set.

In a preferred embodiment of the invention, feet are attached to the tub on the outside of the outer shell. For each foot, a plate which is preferably a metal plate is secured in position against the inner shell prior to the shells being nested together, the plate having an elongated member projecting outwardly from it which member passes through a hole provided for it in the outer shell to project from the outside of the outer shell when the shells are nested together, and a foot is attached to the member on the outside of the outer shell. The elongated member projecting from the gate is preferably a bolt member which passes through a bolt hole in the foot, a nut then being screwed onto the bolt member to attach the foot to the tub.

The preferred tub is a bathtub.

The method of the invention may include the steps of making the female mould and the male mould, the female mould being formed on a male plug and the male mould being formed on a female plug. Each mould may be formed on its respective plug in a manner similar to that used for forming each shell on its respective mould. Thus, in making each mould a gel coat may be first applied to the respective plug and, whether or not that is done, a plastics material may be applied to the respective plug to form the mould. The plastics material is again preferably a fibreglass reinforced resinous material and is preferably applied to the plugs by spraying.

A male mould may be made which is used to form the male plug, whether or not that male mould is also used to make the female shell. The male mould forming the male plug preferably has plastics material applied to its outer surface and finished to provide a smooth outer surface of the plug, the thickness of the plastics material applied determining the size of the female mould that is made from the male plug and hence the size of the male shell that is made from the female mould and hence the width of said cavity when the shells are nested together. The male plug when formed may be separated from the male mould, that facilitating the use of the male mould in making a female shell though in another embodiment the male mould becomes a permanent part of the male plug. In that case the male plug/mould may be used to make female shells or else a separate male mould can be used for that purpose.

The method of the invention may therefore include the steps of making or providing a female plug having a smooth concave inner surface; making a male mould having a smooth convex outer surface by applying a plastics material to the smooth concave inner surface of the female plug then separating the male mould from the female plug; making a male plug having a smooth concave inner surface by applying a plastics material to the smooth convex outer surface of the male mould and building up the thickness ~ 4 - of the plastics material to suit the desired width of said cavity, and providing a smooth convex outer surface to the applied plastics material; making a female mould having a smooth concave inner surface by applying a plastics material to the smooth convex outer surface of the male plug then separating the female mould from the male plug; and using the male and female moulds to complete the making of the tub as defined above.

The moulds are reusable to make more shells to make more tubs.

In a second aspect, the present invention broadly consists in a tub made by the method as defined above.

In a third aspect, the present invention broadly consists in a thermally insulated tub having: an outer shell made from a plastics material, the outer shell having a smooth convex outer surface; an inner shell made from a plastics material, the inner shell having a smooth concave inner surface; the inner shell being nested substantially entirely within the outer shell with a substantial portion of the inner shell being spaced from the outer shell to leave a cavity between them; and a plastics foam material substantially filling the cavity and bonding the shells to make a unitary tub.

The tub may have additional features selected from the preferred features or options set out above.

The above broadly defines the present invention, a preferred embodiment of which will now described with reference to accompanying drawings, in which: Figure 1 shows a perspective view of an "old-fashioned" style of free-standing bath-tub; Figure 2 shows a cross-section through the peripheral flange about the top edge of the bath-tub; Figure 3 shows a cross-section through a bottom portion of the bath-tub showing a drain hole fitting mounted to it; and Figure 4 shows a cross-section through a bottom portion of the bath-tub, in an upside down position, showing the attachment of a foot to the bathtub.

The preferred bath tub of the present invention is a free-standing bath-tub 10 such as shown in Figure 1. The bath-tub may have any suitable shape, whether that be an old or new shape.

The bath-tub has a sandwich construction. In particular, the bath-tub has an inner shell 12 made from a suitable plastics material, an outer shell 14 also made from a suitable plastics material, usually the same as that from which the inner shell is made, and a plastics foam material 16 located between the shells 12 and 14 over a substantial portion of the bath-tub. The shells 12 and 14 are bonded to the core to make a unitary tub.

In the preferred embodiment of the invention, each of the shells 12 and 14 is made from a suitable settable fibreglass reinforced resinous material and the core comprises a settable polyurethane foam material.

The inner shell 12 is formed by spraying fibreglass reinforced resin over a male mould having a smooth surface so that the inner surface of the bath-tub will also be a smooth surface. The exposed outer surface of the sprayed layer on the mould is a somewhat uneven surface. It may, when the layer has gelled but before it has set hard, be rolled so as to improve the evenness of the thickness of the layer. That layer may be about two millimetres thick, for example. When the layer has set, it may or may not be removed from the mould. The outer shell 14 is formed in a similar fashion, but using a smooth-surfaced female mould so that what will be the outer surface of the bath-tub is a smooth surface.

According to the preferred embodiment of the invention, the smoothness of the inner surface of the inner shell and the outer surface of the outer shell is improved by first applying a gel coat to each mould, preferably by spraying, and when the gel coat has gelled then applying the fibreglass reinforced resin over it. The gel coats may be coloured, for example, white, but may have other colours and a different coloured gel coat can be used to provide the inner surface of the inner shell from that used to provide the outer surface of the outer shell.

After the outer shell 14 has set it may or may not be removed from its mould. In either case the inner shell 12 is nested within it. The outer shell 14 has dimensions which are generally larger than those of the inner shell 12 so that when these shells are fitted together they are separated from each other over a substantial portion of the bath-tub to leave a cavity 18 between them. There are various ways in which shells 12 and 14 may be spaced from each other, including the use of spacer elements. However, the preferred bath-tub is provided with a flange 20 about its upper peripheral edge. This is made up of a flange portion 20A about the upper peripheral edge of the inner shell 12 and a flange portion 20b about the upper peripheral edge of the outer shell 14. The dimensions of the inner and outer shells 12 and 14 are such that when they are fitted together, it is just the flange portions 20a and 20b that make contact, as shown in Figure 2. The inner and outer shells 12 and 14 are joined together by their flange portions 20a and 20b and are preferably sealed together, for example, by means of resin. The cavity 18 therefore exists elsewhere between the inner and outer shells 12 and 14. This cavity may have a width of about 16 millimetres, for example.

The settable polyurethane foam is injected through an aperture in the bath-tub and into the cavity 18 wherein foaming occurs to form the foamed core 16 located between and bonded to the shells 12 and 14. To ensure that the foam does fill all parts of the cavity, it is preferred that the foam material is injected into the cavity through a plurality of apertures in the outer shell, for example, three apertures spaced at intervals along the length of the bath-tub. Furthermore, because it is the inner shell of the bath-tub that will be holding water in use and it is important to maintain the integrity of the inner shell for that reason, the apertures used for injection of the foam material into the cavity are preferably provided in the outer shell. While the foam material is foaming within the cavity, the apertures are closed to some extent to help ensure that the foam fills the cavity rather than escaping through the apertures, though air being forced from the cavity by the expanding foam is permitted to escape through the apertures. When the foaming has been completed, any surface foam which has been expressed back through the apertures is removed. The apertures are then sealed, preferably by fibreglass reinforced resin which may have an outer gel coat layer so that where the apertures were is no longer visible. In case it should not be possible to conceal the locations of the apertures completely, the apertures are preferably located along the bottom of the outer shell of the bathtub. One aperture may be left open to be used for a drain hole.

Most bath-tubs have drain hole 22 in a bottom portion of the tub. In the preferred embodiment of the invention so far described, each of the inner and outer shells 12 and 14 is formed with an aperture 24 and 26 respectively in its bottom portion, these apertures being aligned as shown in Figure 3 when the inner and outer shells 12 and 14 are nested together. In the finished bath-tub, a drain hole fitting 28 is fitted in these apertures 24 and 26 but prior to that the apertures provide access to the cavity 18 between the shell 12 and 14. Therefore, the liquid polyurethane, prior to foaming, can be injected into the cavity 18 through either one or both of the apertures 24 and 26. When the foam has set any excess foam is cleared away from around the apertures 24 and 26 so as to leave an aperture through the foam core too. The drain hole fitting 28 is then inserted through these aligned apertures and secured in place. The fitting is preferably sealed in place to prevent water from leaking into the foam. The drain hole fitting 28 may be a standard drain hole fitting or one specially designed for the bath-tubs of the present invention. That fitting shown by way of example in Figure 3 has an upper flange 30 which seats within an annular recess 32 formed about the aperture 24 in the inner shell 12 provided for that purpose. The body 34 of the fitting is shown as being secured by a nut 36 screwed onto a threaded portion of the body. Beyond the nut the body extends at 38 to be connected to a drain pipe in any suitable manner.

According to one embodiment of the invention, the shells are removed from their moulds prior to being nested together. They are preferably clamped together by their flanges during foaming of the cavity. However, depending on the thickness of the shells, the strength of the material from which they are made, the amount of foam material injected into the cavity and the degree to which it foams, the pressure of the expanding foam within the cavity can cause parts of the inner shell to bow inwardly and parts of the outer shell to bow outwardly. The shells can be placed in jigs during foaming to prevent such bowing. However, in another embodiment of the invention, the shells remain mounted to their moulds when they are nested together, and the moulds are clamped together by their flanges. The female mould carrying the outer shell of the bath-tub has apertures in it which are aligned with the apertures in the outer shell through which the foam material is injected into the cavity. The moulds help prevent the pressure of the expanding foam in the cavity from causing unwanted deformation of the shells. Only after the foam filling the cavity has set are the clamps released and the moulds removed from the shells.

If the free standing bath-tub has a sufficiently large flat bottom it may be designed to rest directly on a floor. However, in most cases the bath-tub has four feet attached to it, for example by means of settable resin so that the bath is supported by the feet above the floor.

Referring to the embodiment shown in Figure 4, which shows a partial cross-section through a bottom corner portion of the bath-tub in an upside down position, an arcuate metal plate 40 is secured in position against the inner shell 12. That is done prior to the shells being nested together. The plate can be secured to the inner shell by means of resin. The plate has an elongated member 42 projecting outwardly from it. This member passes through a hole provided for it in the outer shell 14 to project from the outside of the outer shell when the shells are nested together as is shown in Figure 4. A foot 44 made, for example, of cast aluminium alloy is attached to that member 42 on the outside of the outer shell. The elongated member is preferably a bolt member which passes through a bolt hole provided in a flange 46 in the foot. A nut 48 is screwed onto the bolt member to attach the foot to the tub. The plate 40 helps distribute the load applied by the foot to the bath-tub.

The method of the invention may also include the steps of making the female mould and the male mould, the female mould being formed on a male plug and the male mould being formed on a female plug. To help reduce costs, a male mould may be used to form the male plug.

At the start of this process, a female plug is made, for example, of customwood. Its internal shape defines the basic shape of the bath-tub. The internal surface of the plug is coated with a suitable material to provide a smooth release surface. For example, Durotech (TM), a product from Durall Plastics of California, USA may be used for that purpose. The Durotech layer is sanded and polished.

This female customwood plug having a smooth coated concave inner surface is used to make the male mould which, in turn, is used to make the inner shell of the bath-tub. A gel coat is applied to the smooth concave inner surface of the plug and allowed to set. Fibreglass reinforced resin is then sprayed onto the gel coat to a thickness of about 10mm for adequate strength and allowed to set. The thus formed male mould is then removed from the plug.

That male mould or another male mould may, as already indicated, also be used to make the male plug which is in turn used to make the female mould for making the outer shell of the bath-tub. To achieve this, a gel coat is applied to the outside of the male mould followed by a fibreglass reinforced resin spray to a thickness of about 3mm. The resin is allowed to set then more glass and resin are applied to make an adhesive outer surface. Pieces of polyurethane foam sheet are then adhered to that surface to completely cover it. The polyurethane foam sheet is then sanded and shaped to the required shape when it has a thickness of about 15-20mm, that being the desired width of the cavity to be provided between the shells for the foam to be injected. Fibreglass reinforced resin is then sprayed over the shaped foam sheet, sanded when set and then coated with a Durotech spray coat which is in turn sanded and polished to complete the formation of the male plug. This male plug has a smooth convex outer surface which is what is used to make the female mould.

The female mould is made in much the same way as the male mould. To the smooth convex outer surface of the male plug a gel coat is applied and allowed to set. That is followed by a fibreglass reinforced resin spray to a depth of about 6-8mm. When that resin has set the thus formed female mould is removed from the male plug and its smooth concave inner surface is sanded and polished. Holes and apertures are then provided in the female mould, the holes to allow the bolt members 42 to pass through and the apertures are provided for injection foaming of the cavity as previously described.

At this stage, with both the male and female moulds formed, the making of the inner and outer shells can proceed as previously described. The moulds are reused to make other shells for other bath-tubs.

The above describes the preferred embodiment of the present invention and indicates some possible modifications. As will be appreciated by those skilled in the art to which the invention relates, other modifications may be made without departing from the scope of the invention as has been broadly defined.

In one embodiment of the invention, one or both of the shells 12 and 14 may be made from vacuum moulded plastics sheeting or from an injection moulded plastics material, though in this case both surfaces of the or each shell, including the surface which in the completed bath-tub is bonded to the core will be smooth, unlike the case of a sprayed fibreglass reinforced resinous shell. In another modification, one or both of the shells 12 and 14 may be shaped about its aperture 24 and 26 so as to be in direct contact with the other shell, the two shells being joined together at that point. In this case one or more apertures would be provided elsewhere in one of the shells, for example in the bottom of the outer shell 14, for injection of the polyurethane foam material following which the aperture(s) would be closed and preferably sealed.

The invention has been described particularly with respect to its preferred embodiment, that being a bath-tub and most preferably a free standing bath-tub. However, the tub need not necessarily be a bath-tub and, in that case, need not necessarily have a drain hole provided.

The sandwich construction of the tub provides an article which is relatively strong and which, particularly because of the foamed core, is a thermally insulated tub, these features making it particularly suitable for supporting at least one body weight and for holding hot liquids, such as hot water, as in a bath-tub.

Claims (43)

WHAT WE CLAIM IS:

1. A method of making a thermally insulated tub having plastics foam-filled cavity between inner and outer shells of plastics material, the method requiring at least the steps of: applying a plastics material to a female mould having a smooth concave inner surface to form the outer shell of the tub having a smooth convex outer surface; applying a plastics material to a male mould having a smooth convex outer surface to form the inner shell of the tub having a smooth concave inner surface; nesting the inner shell in the outer shell, the inner shell generally having smaller dimensions than those of the outer shell whereby the inner shell is nested substantially entirely within the outer shell with a substantial portion of the inner shell spaced from the outer shell to provide said cavity between them; injecting a settable plastics foam material into the cavity to foam within and substantially fill the cavity and to bond with the shells to make a unitary tub having the smooth concave inner surface of the inner shell on the inside of the tub and the smooth convex outer surface of the outer shell on the outside of the tub.

2. A method according to claim 1 wherein a gel coat is applied to each mould before the plastics material is applied to that mould.

3. A method according to claim 2 wherein the gel coat is coloured.

4. A method according to claim 2 or 3 wherein the gel coat is applied to each mould by spraying.

5. A method according to any one of the previous claims wherein the plastics material is a fibreglass reinforced resinous material.

6. A method according to any one of the previous claims wherein the plastics material is applied to the moulds by spraying.

7. A method according to claim 6 wherein after the plastics material has been sprayed onto the respective mould, the exposed surface of the shell thus formed is evened out.

8. A method according to any one of the previous claims wherein when the inner shell is nested within the outer shell the two shells are joined together substantially about their - 11 - 4 # respective peripheral edges.

9. A method according to claim 8 wherein each of the shells when formed has an outwardly directed flange substantially about its peripheral edge and the shells are joined together by their flanges.

10. A method according to claim 8 or 9 wherein the inner and outer shells are sealed together about their respective peripheral edges.

11. A method according to any one of claims 8-10 wherein when the shells are nested together the cavity is provided between substantially the whole of the inner and outer shells except where they are joined together.

12. A method according to any one of the previous claims wherein the plastics foam material is a polyurethane foam material.

13. A method according to any one of the previous claims wherein the plastics foam material is injected into the cavity through a plurality of apertures in the outer shell and following foaming any surplus foam expressed back through the apertures is removed and at least one of the apertures is sealed.

14. A method according to any one of the previous claims wherein the shells are removed from their moulds prior to being nested together.

15. A method according to any one of claims 1-14 wherein the shells remain mounted to their moulds when they are nested together, and during foaming of the cavity the moulds are clamped together and are released and removed from the shells only after the foam filling the cavity has set.

16. A method according to any one of the previous claims wherein the tub has a drain hole provided in a bottom portion of the tub.

17. A method according to claim 16 wherein each of the shells is provided with an aperture in a bottom portion thereof, which apertures are aligned when the shells are nested together, which apertures also open to the cavity so that either one or both may be used for injecting the foam material into the cavity, and subsequently these apertures in the shells, - 12 - t together with a corresponding aperture provided through the foamed material receive a drain hole fitting.

18. A method according to any one of the previous claims wherein feet are attached to the tub on the outside of the outer shell.

19. A method according to claim 18 wherein for each foot a plate is secured in position against the inner shell prior to the shells being nested together, the plate having an elongated member projecting outwardly from it which member passes through a hole provided for it in the outer shell to project from the outside of the outer shell when the shells are nested together, and a foot is attached to the member on the outside of the outer shell.

20. A method according to claim 19 wherein the elongated member is a bolt member which passes through a bolt hole in the foot, a nut then being screwed on to the bolt member to attach the foot to the tub.

21. A method according to any one of the previous claims wherein the tub is a bath-tub.

22. A method according to any one of the previous claims, the method including the steps of making the female mould and the male mould, the female mould being formed on a male plug and the male mould being formed on a female plug.

23. A method according to claim 22 wherein in making each mould a gel coat is first applied to the respective plug.

24. A method according to claim 22 to 23 wherein in making each mould a plastics material is applied to the respective plug to form the mould.

25. A method according to any one of claims 22-24 wherein a said male mould is used to form said male plug.

26. A method according to claim 25 wherein said male mould forming said male plug has plastics material applied to its outer surface and finished to provide a smooth outer surface of the plug, the thickness of the plastics material applied determining the size of the female mould that is made from the male plug and hence the size of the male shell that is made from the female mould and hence the width of said cavity when the shells are nested together. - 13 - « I

27. A method of making a thermally insulated tub having a plastics foam-filled cavity between inner and outer shells of plastics material, the method requiring at least the steps of: making or providing a female plug having a smooth concave inner surface; making a male mould having a smooth convex outer surface by applying a plastics material to the smooth concave inner surface of the female plug then separating the male mould from the female plug; making a male plug having a smooth concave inner surface by applying a plastics material to the smooth convex outer surface of a male mould and building up the thickness of the plastics material to suit the desired width of said cavity, and providing a smooth convex outer surface to the applied plastics material; making a female mould having a smooth concave inner surface by applying a plastics material to the smooth convex outer surface of the male plug then separating the female mould from the male plug; and using the male and female moulds to complete the making of the tub according to any one of claims 1-21; said moulds being reusable to make more tubs.

28. A method according to claim 1 and substantially as herein described with reference to any embodiment disclosed.

29. A tub when made by the method of any one of the preceding claims.

30. A thermally insulated tub having: an outer shell made from a plastics material, the outer shell having a smooth convex outer surface; an inner shell made from a plastics material, the inner shell having a smooth concave inner surface; the inner shell being nested within the outer shell with a substantial portion of the inner shell being spaced from the outer shell to leave a cavity between them; and a plastics foam material substantially filling the cavity and bonding the shells to make a unitary tub.

31. A tub according to claim 30 wherein the plastics material is a fibreglass reinforced resinous material.

32. A tub according to claim 31 wherein the outer surfaces of outer shell and the inner - 14- surface of the inner shell comprise a gel coat layer.

33. A tub according to any one of claims 30-32 wherein the shells are joined together by their respective peripheral edges.

34. A tub according to claim 33 wherein each shell has an outwardly directed flange about its peripheral edge and the shells are joined together by their flanges.

35. A tub according to claim 32 or 33 wherein the shells are sealed together about their peripheral edges.

36. A tub according to any one of claims 33-35 wherein the cavity is defined between substantially the whole of the shells except where they are joined together.

37. A tub according to any one of claims 33-36 wherein the plastics foam material is a polyurethane foam material.

38. A tub according to any one of claims 33-37 wherein the tub has a drain hole fitting mounted in a bottom portion of the tub.

39. A tub according to claim 38 wherein the tub is a bath-tub.

40. A tub according to any one of claims 33-39 wherein feet are attached to the tub on the outside of the outer shell.

41. A tub according to claim 40 wherein for each foot a plate is secured in position against the inner shell, the plate having an elongated member projecting outwardly from it which member passes through a hole provided for it in the outer shell to project from the outside of the outer shell and a foot is attached to the member on the outside of the outer shell.

42. A tub according to claim 41 wherein the elongated member is a bolt member which passes through a bolt hole in the foot, a nut then being screwed on to the bolt member to attach the foot to the tub.

43. A tub substantially I:\LIBRARY\KCT\SPECS\379609. as herein described with reference to the accompanying^drawings. INTELLECTUAL PROPERTY OFFICE X , r t ' V ■ 'C OFN.Z. 15 JAN 199g> -RECEIVED ^ . v«- By the authorised agents A. J. PARK & SON Per