GB2087295A

GB2087295A - Making baths, basins etc from plastics material

Info

Publication number: GB2087295A
Application number: GB8035690A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-11-06
Filing date: 1980-11-06
Publication date: 1982-05-26

Abstract

A bath, basin or shower tray has an inner liner of thermoplastic material, conventionally formed. This is placed on part of a mould and its reverse side is coated with glass fibre, possibly with one or more rigid reinforcements. Another part of the mould is closed over this and resin and catalyst are impregnated into the glass fibre. This may be applied before the mould is closed, or injected after closure. The shell is cured, removed from the mould and trimmed, the reverse side presenting a smooth surface.

Description

SPECIFICATION Improvements relating to shell-like structures of plastics material This invention relates to the manufacture of shelllike structures of plastics material, and is particularly suitable for baths, shower trays and like toilet receptacles which have to sustain a considerable load.

Such receptacles are now commonly made of plastics material, and generally there is an inner skin or liner of smooth or glossy plastics, often coloured, such as acrylic resin. This is thermoplastic and readily moulded into an acceptable shape. However, it is not strong enough to sustain localised loads, and reinforcement has to be provided.

The usual strengthening is provided by glass-fibre reinforced plastics material (GRP). This can be laid up by hand or sprayed onto the reverse or nonexposed side of the liner. A timber based reinforcing board is also often required, for example along the bottom of a bath, and the rim may also be strengthened by a frame.

This technique has a number of drawbacks. The manually applied coating tends to vary in thickness and in strength, and is prone to delamination from the liner, and/or the baseboard. Flexing is never entirely eliminated and can be considerable. It leaves a a rough external surface to which water supply and waste fittings do not closely marry, without additional re-working, and which can leave projecting fibres hazardous to plumbers. During manufacture, this method releases excess styrene into the atmosphere, and the finished article still requires metal or wood frames for support. Even so, the flanges tend to yield under load more than the elasticity of any sealing compound between the flanges and adjacent walls can tolerate, and unless extra supports are provided the seal is broken and seepage may occur.

It is the aim of this invention largely to overcome these problems.

According to one aspect of the present invention there is provided a method of making a shell-like receptacle, such as a bath, vanity basin or shower tray, comprising the steps of: i) forming an inner liner of a synthetic plastics material; ii) placing the liner on one part of a mould with its reverse side exposed; iii) applying a controlled layer of glass fibre over this reverse side, with or without supplementary inserts; either iv) closing the mould and by bringing another part into co-operation with the first part, with the glass fibre occupying a space between this other part and the liner; and v) adding synthetic resin and catalyst into said space to permeate the glass fibre; orvi) adding a controlled quantity of resin and catalyst to the other part of the mould before closing the two parts of the mould, and vii) curing the resin and subsequently removing the new reinforced liner from the mould.

According to another aspect of the present invention there is provided a shell-like receptacle made by the above method.

The use of a closed mould practically eliminates the hazard of styrene release into the atmosphere.

When the shell emerges from the mould, its reverse side will be smooth and all that will be required is an edge trim or minor de-flashing operation and inspection. Plumbing fittings are easy to install with such an external surface and may even be incorporated into the tool and bonded in.

Reinforcement beyond the GRP will generally be needed in certain areas, such as the bottom of a bath. This can be included in the process by sandwiching a board between layers of glass fibre so that it will be totally encased.

The liner will preferably be an acrylic resin sheet, or any other suitable thermoformable plastic, heated and vacuum-formed into the desired shape in conventional fashion. When transferred to the mould used in the present process, it is important that it should fit accurately, within close tolerances. If it were substantially oversize, for example, the mould might not close properly without damaging the liner, and if it were distorted it might cause the GRP space to have zones of unacceptable thickness. Therefore this technique does require liners to be formed to definable tolerances. However, given that, the predetermined thickness achieved with the closed mould will make for a consistent product, and the process as a whole can offer speedier output at less cost than previously.

The accompanying drawing shows, by way of example, part of a bath (inverted) with GRP and board reinforcement, as parted from the mould (not shown).

CLAIMS (filed on 5/11/81) 1. A method of making a shell-like receptacle, such as a bath, vanity basin or shower tray, comprising the steps of: i) forming an inner liner of a synthetic plastics material; ii) placing the liner on a first part of a mould with its reverse side exposed; iii) applying a controlled layer of glass fibre over this reverse side; either iv) closing the mould by bringing a second part into co-operation with the first part, with the glass fibre occupying a space between this second part and the liner; and v) adding synthetic resin and catalyst into said space to permeate the glass fibre; or vi) adding a controlled quantity of resin and catalyst to the exposed side of the liner before closing the coated liner in the mould by bringing a second part into co-operation with the first part, and vii) curing the resin and subsequently removing the now reinforced liner from the mould.

2. A method as claimed in claim 1, wherein a rigid insert is included in the glass fibre layer.

3. A method as claimed in claim 2, wherein the insert is sandwiched between layers of glass fibre so that it will be totally encased.

4. A method as claimed in Claim 1,2 or 3,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

SPECIFICATION Improvements relating to shell-like structures of plastics material This invention relates to the manufacture of shelllike structures of plastics material, and is particularly suitable for baths, shower trays and like toilet receptacles which have to sustain a considerable load.

Such receptacles are now commonly made of plastics material, and generally there is an inner skin or liner of smooth or glossy plastics, often coloured, such as acrylic resin. This is thermoplastic and readily moulded into an acceptable shape. However, it is not strong enough to sustain localised loads, and reinforcement has to be provided.

The usual strengthening is provided by glass-fibre reinforced plastics material (GRP). This can be laid up by hand or sprayed onto the reverse or nonexposed side of the liner. A timber based reinforcing board is also often required, for example along the bottom of a bath, and the rim may also be strengthened by a frame.

This technique has a number of drawbacks. The manually applied coating tends to vary in thickness and in strength, and is prone to delamination from the liner, and/or the baseboard. Flexing is never entirely eliminated and can be considerable. It leaves a a rough external surface to which water supply and waste fittings do not closely marry, without additional re-working, and which can leave projecting fibres hazardous to plumbers. During manufacture, this method releases excess styrene into the atmosphere, and the finished article still requires metal or wood frames for support. Even so, the flanges tend to yield under load more than the elasticity of any sealing compound between the flanges and adjacent walls can tolerate, and unless extra supports are provided the seal is broken and seepage may occur.

It is the aim of this invention largely to overcome these problems.

According to one aspect of the present invention there is provided a method of making a shell-like receptacle, such as a bath, vanity basin or shower tray, comprising the steps of:

i) forming an inner liner of a synthetic plastics material;

ii) placing the liner on one part of a mould with its reverse side exposed;

iii) applying a controlled layer of glass fibre over this reverse side, with or without supplementary inserts; either iv) closing the mould and by bringing another part into co-operation with the first part, with the glass fibre occupying a space between this other part and the liner; and v) adding synthetic resin and catalyst into said space to permeate the glass fibre; orvi) adding a controlled quantity of resin and catalyst to the other part of the mould before closing the two parts of the mould, and

vii) curing the resin and subsequently removing the new reinforced liner from the mould.

According to another aspect of the present invention there is provided a shell-like receptacle made by the above method.

The use of a closed mould practically eliminates the hazard of styrene release into the atmosphere.

When the shell emerges from the mould, its reverse side will be smooth and all that will be required is an edge trim or minor de-flashing operation and inspection. Plumbing fittings are easy to install with such an external surface and may even be incorporated into the tool and bonded in.

Reinforcement beyond the GRP will generally be needed in certain areas, such as the bottom of a bath. This can be included in the process by sandwiching a board between layers of glass fibre so that it will be totally encased.

The liner will preferably be an acrylic resin sheet, or any other suitable thermoformable plastic, heated and vacuum-formed into the desired shape in conventional fashion. When transferred to the mould used in the present process, it is important that it should fit accurately, within close tolerances. If it were substantially oversize, for example, the mould might not close properly without damaging the liner, and if it were distorted it might cause the GRP space to have zones of unacceptable thickness. Therefore this technique does require liners to be formed to definable tolerances. However, given that, the predetermined thickness achieved with the closed mould will make for a consistent product, and the process as a whole can offer speedier output at less cost than previously.

The accompanying drawing shows, by way of example, part of a bath (inverted) with GRP and board reinforcement, as parted from the mould (not shown).

CLAIMS (filed on 5/11/81) 1. A method of making a shell-like receptacle, such as a bath, vanity basin or shower tray, comprising the steps of:

i) forming an inner liner of a synthetic plastics material;

ii) placing the liner on a first part of a mould with its reverse side exposed;

iii) applying a controlled layer of glass fibre over this reverse side; either iv) closing the mould by bringing a second part into co-operation with the first part, with the glass fibre occupying a space between this second part and the liner; and v) adding synthetic resin and catalyst into said space to permeate the glass fibre; or vi) adding a controlled quantity of resin and catalyst to the exposed side of the liner before closing the coated liner in the mould by bringing a second part into co-operation with the first part, and vii) curing the resin and subsequently removing the now reinforced liner from the mould.
2. A method as claimed in claim 1, wherein a rigid insert is included in the glass fibre layer.
3. A method as claimed in claim 2, wherein the insert is sandwiched between layers of glass fibre so that it will be totally encased.
4. A method as claimed in Claim 1,2 or 3, wherein the inner liner is a thermoplastic sheet heated and vacuum formed to correspond to the shape of thefirst part of the mould.
5. A method of making a shell-like receptacle substantially as hereinbefore described with reference to the accompanying drawing.
6. A shell-like receptacle made by the method of any preceding claim.