GB2212098A

GB2212098A - Methods for moulding structures

Info

Publication number: GB2212098A
Application number: GB8826243A
Authority: GB
Inventors: Anthony Joseph Rowett
Original assignee: Radiant Stellite S A
Current assignee: Radiant Stellite S A
Priority date: 1987-11-11
Filing date: 1988-11-09
Publication date: 1989-07-19
Also published as: GB8826243D0; GB8726429D0

Abstract

A method for moulding a structure comprises a panel of a first reinforced plastics material and a body of a second plastics material, which may be any unfilled or a reinforced plastics material which body projects out of a surface defined by the panel except at an edge region of the body that meets the panel. The panel and the body are moulded one after the other using a common mould by which an interface is defined between the two moulds and the first to be moulded of the panel and the body is less than fully hardened when material to form the second to be moulded of the panel and the body is applied to the mould so that the plastics materials of the panel and the body become chemically bonded at their interface. <IMAGE>

Description

METHODS FOR MOULDING STRUCTURES This invention relates to a method of moulding a two part structure with a clean well-adhered interface line.

More specifically, the invention provides a method for moulding a structure comprising a panel of a first reinforced plastics material and a body of a second plastics material which may be an unfilled or a reinforced plastics material which body projects out of a surface defined by the panel except at an edge region of the body that meets the panel, wherein: (a) the panel and the body are moulded one after the other using a common mould by which an interface between the panel and the body is defined; and (b) the first to be moulded of the panel and the body is less than fully hardened when material to form the second to be moulded of the panel and the body is applied to the mould so that the plastics materials of the panel and the body become chemically bonded at the interface between the panel and the body.

In particular it can provide a method for moulding a panel having an insert which comprises: providing a mould formed with a base region defining said panel and an upstanding region defining said insert; introducing a first flowable polymerisable reinforced resin composition into the base region of said mould, levelling said composition or allowing said composition to level so that said composition covers said base region up to said insert and allowing said composition to harden;; after said first resin composition has hardened but before hardening is complete covering the upstanding region protruding above the insert with a second hardenable reinforced resin composition so that as said second composition hardens it defines the insert which is joined to the panel defined by the first composition and so that resin of the first composition becomes copolymerised across a line of junction with resin of the second composition to join the insert monolithically to the panel.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a view of a washbasin and surround made according to the invention, the view being taken in longitudinal vertical section; and Figure 2 is a diagrammatic perspective view of a mould for making a washbasin and surround according to the invention.

In Figure 1, a washbasin structure to be made by the method of the invention includes a panel-like surround 10 formed with an aperture 12 beneath which is attached a washbasin 14. The material of the surround 10 is typically a synthetic marble made using a polymerisable resin filled with an inorganic filler. The material of the washbasin 14 which is usually of a contrasting colour is typically glass reinforced polyester. A problem arises at the interface between the bowl 14 and the surround 10. If the bowl 14 and surround 10 are made separately and then adhered together it is difficult to obtain a clean line of junction. The product exhibits weakness and a potential for delamination along the join line which further provides a route for potential water ingress and a locus for contamination by growth of microorganisms that is unhygienic.Accordingly it is an object of the invention to eliminate a join line between separately moulded parts and to produce a quality of better appearance, strength and hygiene properties.

According to the invention the surround 10 and basin 14 are moulded in a single mould 15, the parts 10, 14 being designed so that they can be made sequentially at separate regions 17, 19 of the mould 15 but in a continuous operation so that a monolithic product is obtained. Thus the mould 15 has a generally planar base region 17 defining the surround 10 and an upstanding plug 19 defining the shape of the basin 14.

In use, the regions 17, 19 are first coated with wax or other suitable release agent, after which, assuming that a gel coat is required over the whole product surface, the mould 15 is sprayed or otherwise coated with a gel coat to give a clear gel coat 10-20 thousandths of an inch thick. The gel coat is allowed to gel, after which the base region 17 is filled with a flowable self-levelling settable filled plastics composition. The composition suitably contains resin to filler in a proportion of from 1 to 2 to 1 to 4 by weight, the proportion being selected to give the desired combination of product quality and flow characteristics.

The resin may be a polyester, an epoxy or an acrylic resin, and suitable fillers include dolomite or other forms of calcium carbonate, alumina trihydrate which is preferred on account of its combination of translucence and fire-retardent properties, talc, plaster of paris, silica sand, marble chips or quartz, crushed polyester or other plastic material chips. An organic filler such as wood flour may also be used for some effects. The resin composition is applied to the region 17 to give a layer typically about one inch thick which may be pigmented both homogeneously to give a background colour and inhomogeneously to give marble-like pigment veins through the thickness of the surround 10. A curing catalyst such as methyl ethyl ketone peroxide is also present.The composition to form the surround 10 is allowed to level either simply by gravity or with vibration to assist levelling and remove trapped air.

For moulding the bowl 14, after the surround 10 has hardened, but before full hardness has been reached, the plug 19 is coated with a second hardenable composition such as glass-reinforced polyester. The bowl 14 is monolithically adhered to the surround 10 with the active radicals present in the material of the surround 10 achieving copolymerisation with the molecules of the material of the bowl 14 across the interface 16 giving rise to a structure in which the two materials are chemically interlinked across the interface 16. For this result to be achieved the surround 10 should be incompletely hardened, and the bowl 14 is made typically from 4 hours or less to 10 hours after the surround 10.

Any suitable matrix may be used for the compositions to form the bowl 14 and surround 10 and any suitable reinforcing materials such as carbon or glass fibre may be used. The bowl matrix may be filled or unfilled, the only compatibility requirement being that of the fillers or reinforcers with the resins used.

In a modification the invention may use a surround 10 of natural marble granite, natural stone or other naturally occurring material having an aperture therein, the aperture being treated with a plastics resin and the resin being incompletely hardened before the bowl is made.

Claims

CLAIMS:

1. A method for moulding a structure comprising a panel of a first reinforced plastics material and a body of a second plastics material which may be any unfilled or a reinforced plastics material which body projects out of a surface defined by the panel except at an edge region of the body that meets the panel, wherein: (a) the panel and the body are moulded one after the other using a common mould by which an interface between the panel and the body is defined; and (b) the first to be moulded of the panel and the body is less than fully hardened when material to form the second to be moulded of the panel and the body is applied to the mould so that the plastics materials of the panel and the body become chemically bonded at the interface between the panel and the body.

2. A method according to Claim 1, wherein the mould includes a female portion for moulding the body.

3. A method according to Claim 1, wherein the mould includes a male portion for moulding the body.

4. A method for moulding a panel having an insert which comprises: providing a mould formed with a base region defining said panel and an upstanding region defining said insert; introducing a first flowable polymerisable reinforced resin composition into the base region of said mould, levelling said composition or allowing said composition to level so that said composition covers said base region up to said insert and allowing said composition to harden;; after said first resin composition has hardened but before hardening is complete covering the upstanding region protruding above the insert with a second hardenable reinforced resin composition so that as said second composition hardens it defines the insert which is joined to the panel defined by the first composition and so that resin of the first composition becomes coplymerised across a line of junction with resin of the second composition to join the insert monolithically to the panel.

5. A method according to Claim 4, wherein the insert is a bowl and the panel is a surround for the bowl.

6. A method according to Claim 4 or 5, wherein the first composition is a polyester, epoxy or acrylic resin filled with an inorganic filler.

7. A method according to Claim 6, wherein 2-4 parts by weight of filler are present per part by weight of resin.

8. A method according to Claim 3 or 4, wherein filler is selected from marble chips, calcium carbonate, alumina trihydrate, talc, plaster of paris, quartz, silica sand and crushed polyester and other plastic material chips.

9. A method according to any preceding claim, wherein the second resin composition is a glass reinforced polyester.

10. A method according to any preceding claim, wherein the first composition is levelled by gravity.

11. A method according to any of Claims 4 to 10, wherein the first composition is levelled by being vibrated.

12. A method according to any preceding claim, wherein the first composition includes veins of pigment dispersed therein.

13. A modification of the method of Claim 4, wherein the surround is of natural marble granite, natural stone or other naturally occurring mineral material having an aperture therein, resin being applied to the marble or other material and partly cured before the bowl material is applied to an upstanding plug protruding through the aperture.