GB2340062A

GB2340062A - Water container moulded with an anti-bacterial agent

Info

Publication number: GB2340062A
Application number: GB9912343A
Authority: GB
Inventors: Simon Osbourne
Original assignee: Glynwed Consumer and Building Products Ltd
Current assignee: Glynwed Consumer and Building Products Ltd
Priority date: 1998-05-26
Filing date: 1999-05-26
Publication date: 2000-02-16
Also published as: GB9912343D0; GB9811298D0; GB2340062A8

Description

2340062 DOMESTIC WATER CONTAINERS WITH ANTI-BACTERIAL PROPERTIES This

invention relates to domestic water containers with anti-bacterial properties, and in particular to such containers which are fixtures adapted to be regularly filled with water and later emptied, and which are subject to contamination, particularly sinks, washbasins, baths and shower trays.

It is known that there is an increasing consumer demand for the environment in which the consumer lives and works to be as clean and bacteria-free as possible. This is particularly the case in the areas of perceived high risk such as the parts of the kitchen and the bathroom that are both regularly wetted and which come into contact with bacterial nutrients such as human food, or bodily fluids. A particular problem is that although the surfaces of kitchen and bathroom fittings may be subject to regular and indeed effective cleaning, for example by wiping over with a bactericidal solution, there are areas, for example around overflow outlets and plugholes, which cannot be easily reached and where bacterial contamination may remain.

It is known that bacterial cleanliness of a sink can be achieved by applying a permanent surface film of antibacterial agent to the sink (see for example the disclosures of JP 07331017 A, JP 06065507, and JP

08026805). This approach has the advantage over applying a bactericidal cleaner that maintaining the surface free of bacteria does not rely an the person wiping or washing the sink, and doing so on a sufficiently regular basis, and indeed completely. The approach of providing a surface coating is, however, disadvantageous in that abrasion or cutting of the surface can damage the antibacterial film and leave areas of the surface on which bacteria can grow. Also the cost of providing the surface film or coating adds materially to the cost of manufacture, and the efficacy of the film decreases over time. This last factor is of particular importance when considering that the service life of such fixed installations is often many years.

We have now found that if such items are manufactured by a method which incorporates an anti-bacterial agent into the material of which the item is made prior to forming the material into the item itself, the resulting item exhibits anti-bacterial properties over a long period, and does so over its entire surface, even parts which cannot easily be accessed once the item is installed.

According to the present invention there is provided a method of manufacturing a domestic water container which comprises incorporating into a moulding or casting composition an effective amount of an anti-bacterial agent and subsequently forming the composition into a water container for installation in a domestic environment, for example a sink, washbasin, bath or shower tray.

The invention may be used in particular with moulding or casting compositions based on epoxy resin systems. The epoxy system is mixed with an anti-bacterial agent in appropriate form to form a composite system, that composite system is liquefied, the liquefied composite system is cast into a mould, allowed to set and the casting then is removed from the mould and cured. The form of the anti-bacterial agent used is determined by the form of the epoxy system. For example, if the epoxy system was in powder form, then the anti-bacterial agent used would be in powder form.

In a particularly preferred embodiment of the present invention the base material for the manufacture is a powder epoxide resin/anhydride hardener mixture and the method of manufacture is as described in British patent specification 2216841A, the contents of which are incorporated into this text by reference.

Other possible base materials for the present invention are acrylic based materials, polypropylene or polybutylene terephthalate. Using these materials, the method of the present invention may be performed using known techniques once the anti-bacterial agent has been incorporated. The actual forming of the container may take place by a variety of known moulding or casting techniques, e.g. injection moulding.

The most preferred anti-bacterial agent for use in the present invention is 2,4,41-trichloro-21-hydroxy diphenyl ether which is known by the common name of triclosan. Preferably, the anti-bacterial agent is present in quantities of greater than 0.1%, preferably in the range of 0.2 to 1.0%, and most preferably in the range 0.2 to 0.4%, all percentages being given as percentages by weight of the total weight of the composite mixture.

The method of the present invention has the considerable advantage that an item made by the method of the present invention incorporates the antibacterial agent throughout its structure. It has been found that the anti-bacterial agent incorporated into the structure will slowly diffuse to areas of low concentration of antibacterial agent. This has the effect that if any antibacterial agent is lost from the surface of the item, it is replaced from within the structure of the item.

It is often the case that when installed sinks, baths, shower trays and the like, only have one face or surface that is exposed to contact with the user of the item, for example a sink unit for building into a work top. In accordance with a particularly preferred feature of the present invention, after the main moulding or casting step has been effected, the face(s) of the item which will normally not be contacted by the user once installed, or which are normally concealed or inaccessible, are coated with a film or layer of a material substantially impervious to the anti-bacterial agent. This has the effect that no diffusion of the anti-bacterial agent will occur towards the non- contacted surface of the item; this may lengthen the effective life of the anti-bacterial properties of the item.

Examples of the method of the present invention are given by way of illustration and are as follows:

Example 1

A combined sink and drainer unit weighing just under 10kg is made by taking 10kg of an epoxide resin and anhydride hardener mixture which is in powder form at room temperature. A suitable mixture is CPR 100, a mono white casting system which is available from Bitrez Limited. 0.02kg of powdered triclosan (available from Bitrez Limited or Ciba Specialty Chemicals Plc) is added to the epoxide resin/anhydride hardener mixture and mixed by appropriate mixing means into the epoxide resin/anhydride hardener mixture to form a composite mixture. 5 The composite mixture is pre-heated to a temperature in the range of 50 to 60C throughout which causes it to liquefy. 0.02kg of an appropriate catalyst such as CPH 103 or CPH 105 (both available from Bitrez Limited) to improve cure time later in manufacture is now mixed into the liquid composite mixture under such conditions as to prevent any air entrainment. The liquid composite mixture is then injected into a preheated mould under a pressure of between 280 and 28OOg/cm' (4 to 50 psi).

Once the injected mixture has set to a form stable state, the casting is removed from the mould and placed in a curing oven which has a nominal temperature of 135C for a period of around 2.5 hours.

The material that forms the resultant sink has antibacterial properties and, specifically, has been found to be effective against at least certain species of bacteria viz. Staphylococcus aureus (American Type Culture Collection 6538), Escherichia coli (National Collection of Type Cultures 8196), and Salmonella typhimurium. (National Collection of Type Cultures 5710).

Example 2

A combined sink and drainer unit weighing just under 10kg is made by taking 10kg of polypropylene supplied in pellet form. 0.3% by weight, (0. 03kg) of powdered triclosan is added to the pellets as they are fed into a heater such as a heated feed screw to form a composite mixture.

As the pellet/powder mixture in the heater is heated the pellets melt and the powdered triclosan melts into the polypropylene. The molten material is held in the heater and agitated thereby for a sufficient length of time to 5 allow complete mixing of the polypropylene and the triclosan. Once the composite mixture is at the appropriate temperature for moulding and the mixing time has elapsed, it is injected into the mould. The moulding is left to cool, and once the composite mixture is sufficiently solidified the sink removed from the mould and left to cool completely.

If the triclosan and polypropylene has not formed a wholly homogeneous mixture when in the feed screw, the triclosan will diffuse through the moulded sink and thus any zones of relatively low triclosan concentration will, over time, increase in concentration.

In this example, polybutylene terephthalate can be substituted for polypropylene.

Example 3

A combined sink and drainer unit weighing just under 10kg is made by taking 10kg of polypropylene supplied in pellet form. The pellets had been pre-coated with a dye and triclosan in a quantity of approximately 0.3% by weight of the pellet.

The pellets are placed in a heated feed screw and melted. When the molten polypropylene is at the correct temperature it is injected into the mould as in example 2 above.

7 Example 4

A combined sink and drainer unit weighing just under 10kg is made by taking appropriate quantities of an acrylic resin and hardener, both in liquid form to result in 10kg of material when mixed. A suitable acrylic resin system may be obtained from Schock Systems Limited or ICI Plc. 0.3% by weight (0.03kg) of triclosan powder is added to either the acrylic resin or the hardener and thoroughly dispersed or dissolved in that part. The two parts of the system are then thoroughly mixed to form the composite mixture, and that composite mixture injected into the mould.

The filled mould is then orientated so that the surface of the sink that will be contacted by users of the sink is downward of the rest of the sink. Once the composite mixture has set, generally after about 1 hour, the sink is removed from the mould.

claims 1. A method of manufacturing a domestic water container which comprises incorporating into a moulding or casting composition an effective amount of an anti bacterial agent and subsequently forming the composition into a water container for installation in a domestic environment.

2. A method according to claim 1 in which the container is a sink.

3. A method according to claim 1 in which the container is a shower tray.

4. A method according to any one of claims 1 to 3 in which the composition is based on acrylic moulding materials, polypropylene, polybutylene terephthalate or an epoxy resin moulding system.

5. A method according to any one of claims 1 to 3 in which the composition is based on polypropylene in the form of pellets, and wherein the incorporation of the anti-bacterial agent is effected by coating the pellets with a substance that is or includes an anti-bacterial agent.

6. A method according to any one of claims 1 to 5 in which the anti-bacterial agent is 2,4,41-trichloro 2'-hydroxy diphenyl ether.

7. A method according to any one of claims I to 7 in which the anti-bacterial agent is present in a concentration of at least 0.1% by weight of the composite mixture.

8. A method according to any one of claims 1 to 7 in 9 which the anti-bacterial agent is present in a concentration of 0.2 to 1. 0% by weight of the composite mixture.

9. A method according to any one of claims 1 to 7 in which the antibacterial agent is present in a concentration of 0.2 to 0.4% by weight of the composite mixture.

10. A method according to any one of claims 1 to 9 and wherein after the container has been formed, part of its exterior is coated to provide a surface coating that is substantially impervious to the antibacterial agent. 15 11. A method of making a domestic water container substantially as hereinbefore described with reference to any one of Examples 1 to 4.

12. A domestic water container produced by the method of any one of claims 1 to 11.