Patent Description:
Multi resistant bacteria are becoming more and more a problem, especially in hospital environment. To minimize the risk of contamination, extensive cleaning of surfaces which are touched by many people should be performed frequently (which is time consuming and costly). Nowadays, to obtain a surface with anti-microbial function, additional coatings (based on toxic or metallic particles) are sometimes applied, or anti-microbial additives are added to the resin of e.g. light switches.

Hospital-acquired infections can be caught by direct contact with common surfaces like switches, door handles etc. To break the cycle of contamination, an anti-microbial finishing can be provided for such surfaces. The anti-microbial effect is obtained either by applying an anti-microbial coating or anti-bacterial additives into the plastic resin. In both cases toxic metal ions (e.g. Ag or Cu) or other chemicals are slowly released into the environment resulting in a limited lifetime of the biocidal effect as well as contamination of the environment. The coating may be difficult to apply (additional process step) and costly. Abrasion of the coating will also reduce the anti-microbial function.

Ultraviolet (UV) light, as well as visible violet and blue light, is known to have bactericidal or inhibiting effects. For instance, rooms may be irradiated with UV light when not in use. However, when in use, such general irradiation would be a health hazard for persons in the room.

<CIT> discloses the use of an ultraviolet lamp in a light switch such that the transparent button of the switch is disinfected by the ultraviolet light.

<CIT> discloses a key button with an anti-bacterial light source. The button has a transparent keycap. Ultraviolet light emitted by an ultraviolet lighting element enter into a light guide block, and is then reflected by the light guide block to pass through the keycap to arrive to a second side surface of the keycap.

<CIT> discloses e.g. a front panel of a drawer, guiding disinfectant UV light.

<CIT> discloses a moulded decorative part for a vehicle interior, comprising an excitation source for emitting electromagnetic waves and a luminescent material which is excitable by the electromagnetic waves from the excitation source to emit light in the visible range.

The inventors have now realised that an in-mould decoration/back injection moulding process can be used to combine a light emitting film (e.g. comprising a light source or being a light guide for an external light source) with a moulded substrate, e.g. a part of a light switch or door handle or the like which is often touched by different persons, for anti-microbial (e.g. antibacterial) function using blue light. In-mould decoration makes it possible to obtain the anti-microbial function during moulding of the component (i.e. substrate plus film) in a cost efficient way. No additional coating step may be necessary. No release of toxic particles will occur either from a coating or from the component itself.

It is to be noted that any feature of any of the aspects may be applied to any other aspect, wherever appropriate. Likewise, any advantage of any of the aspects may apply to any of the other aspects.

<FIG> illustrate a mould <NUM> which can be used for so called in-mould decoration and/or back injection moulding to combine a flexible film <NUM> (for emitting the antibacterial light) with the plastic substrate to form a component (part of switch, button, handle or the like), to obtain an anti-microbial surface of the component. The mould typically comprises a movable mould part (movable mould half), which is shown to the left in the figures, and a fixed mould part (fixed mould half), which is shown to the right in the figures.

<FIG> shows the mould <NUM> open, with a movable half 3a and a fixed half 3b of the mould separated from each other. The film <NUM> maybe introduced into the mould <NUM> as a web being passed between the movable and fixed halves 3a and 3b e.g. by means of rolls <NUM>. The film <NUM> is applied to an inner surface <NUM> of the movable half 3a, e.g. by means of clamps <NUM> and/or suction as illustrated by the arrows in the figure.

<FIG> shows the mould being closed, by the movable half 3a being moved towards the fixed half 3b such that the fixed half 3b is pressed against the movable half 3a, forming a mould cavity <NUM> there between. The inner surface <NUM> of the movable half 3a, having the film <NUM> applied to at least a part thereof, forms a wall delimiting the mould cavity <NUM>. When the mould is thus closed, the plastic substrate material can be injected into the mould cavity <NUM>, typically via a hole (called spruce) <NUM> having an opening gate <NUM> into the mould cavity.

When the material is injected in liquid, e.g. molten, form, the material fills the mould cavity <NUM> and is formed into the substrate onto a top surface of which the film <NUM> is adhered. If the substrate material is thermoplastic, the material is injected at an elevated temperature at which the material is liquid. The material is then cooled within the mould cavity whereby it is solidified. Similarly, if the substrate material is curable, the material may be cured within the mould cavity whereby it is solidified.

The solid substrate having the film <NUM> adhered to a top surface thereof may then be removed from the mould <NUM>, after the movable and fixed halves 3a and 3b have once again been separated from each other.

<FIG> illustrates a component <NUM> comprising a moulded substrate <NUM> having a film <NUM> adhered to a top surface <NUM> thereof, which may have been produced in accordance with the injection moulding process discussed in relation to <FIG>. That the surface <NUM> to which the film <NUM> is adhered is a top surface implies that it is an outer surface which is arranged to be proximal to touches from persons using the component. The film is thus arranged to be touched by such persons, which is why it is desirable that the film has antibacterial (or, more generally, anti-microbial) properties to avoid transmission of pathogens from one person to another.

In accordance with the present invention, the film is arranged to emit light having antibacterial properties from a light source. As discussed in relation to <FIG>, the light source may be comprised in the film <NUM>. However, in the embodiment of <FIG>, the light source <NUM> is external to the film <NUM> and the film is arranged to act as a light guide, guiding light from the external light source and emitting it from and throughout its top surface <NUM>. Thus, bacteria and other microbes deposited on the top surface <NUM> of the film (typically by a person touching the film) may be inhibited or killed by the light emitted there from. In order to act as a light guide, the film <NUM> is transparent, or comprises at least one transparent top layer, e.g. of polycarbonate (PC) or poly(methyl methacrylate) (PMMA) material.

The light source <NUM> may be or comprise any light source emitting sufficient amounts of light of a suitable wavelength to be antibacterial. It may be preferred to use a light source which specifically emits light at such a suitable wavelength, thus emitting in a narrow spectrum. Examples of such light sources include a Light-Emitting Diode (LED) and a laser. An LED may be preferred since it is relatively cheap and easily maintained, and may give a relatively uniform emission of light over the top surface <NUM> of the film. The light source <NUM> may comprise a plurality (e.g. array) of LEDs or other light sources, e.g. arranged along a side of the film <NUM>. The LED may e.g. comprise indium gallium nitride (InGaN) which typically gives blue or violet visible light, but any other suitable LED type may alternatively be used.

<FIG> illustrates that the film <NUM> may be composed of a plurality of different layers, typically laminated to each other. If the light source is comprised in the film <NUM>, the film may comprise a luminous layer <NUM>, e.g. an electroluminescent layer or a fluorescent layer, emitting light at an antibacterial wavelength.

For instance, if the luminous layer <NUM> is electroluminescent, the luminous layer <NUM> is typically stacked between a back electrode layer <NUM> and a front electrode layer <NUM>. A dielectric layer <NUM> may be included between the back electrode layer <NUM> and the luminous layer <NUM>. An electrically insulating bottom layer <NUM> maybe included in the film to insulate the electrode layers from the substrate <NUM>. Similarly, an electrically insulating top layer <NUM> may be included in the film to insulate the electrodes from e.g. persons touching the film <NUM>, e.g. of polycarbonate (PC) or poly(methyl methacrylate) (PMMA) material. When a voltage is applied between the back and front electrode layers <NUM> and <NUM>, the luminous layer <NUM> will be induced to emit light of a desired antibacterial wavelength. For the emitted light to be emitted through the top surface <NUM> of the film, any layers <NUM> and <NUM> positioned above the luminous layer <NUM> (i.e. between the luminous layer <NUM> and the top surface <NUM> of the film) are transparent to that light.

Regardless of whether the light source is external to or comprised in the film <NUM>, and regardless of whether the light source comprises an array of distinct light sources, the light source is arranged to emit visible light having a wavelength within the range of <NUM> to <NUM>, e.g. <NUM> to <NUM>, which is easily obtained e.g. by means of LED while not being harmful to humans as UV light of shorter wavelengths may be.

<FIG> is a schematic flow chart of an embodiment of the method of producing the moulded component <NUM>, of the present disclosure. The method comprises applying S1 a film <NUM> to an inner wall <NUM> of a movable half 3a of the mould <NUM>. The method also comprises closing S2 the mould <NUM> such that a mould cavity <NUM> is formed between the inner wall <NUM>, having the film <NUM> applied there to, and a fixed half 3b of the mould. The method also comprises injecting S3 a plastic substrate material into the cavity <NUM> through a spruce <NUM> in the mould <NUM>, such that a substrate <NUM> is formed in the cavity, the film <NUM> adhering to a top surface <NUM> of said substrate <NUM>. The method also comprises allowing the substrate material to solidify. The method also comprises removing S5 the substrate <NUM> and thereto adhered film <NUM> from the mould <NUM>. The method also comprises arranging S6 the film <NUM> to emit light having antibacterial properties from a light source <NUM> and/or <NUM> forming the component <NUM> with said substrate <NUM> and thereto adhered film <NUM>.

The light source is arranged to emit visible light having a wavelength within the range of <NUM> to <NUM>, e.g. <NUM> to <NUM>. These wavelength have been shown to have anti-microbial properties. Visible light may be preferred in order to avoid any health concerns relating to UV light.

In some embodiments of the present invention, the film <NUM> is configured to act as a light guide for light emitted from the light source <NUM> when it is located externally of the film, e.g. as in <FIG>. In some embodiments, the light source <NUM> comprises a Light-Emitting Diode (LED) e.g. comprising indium gallium nitride (InGaN) which is associated with suitable wavelengths.

Additionally or alternatively, in some embodiments of the present invention, the light source is comprised in the film <NUM>, e.g. in the form of a luminous layer <NUM> of the film <NUM>. In some embodiments, the luminous layer <NUM> is an electroluminescent layer. Alternatively, the luminous layer <NUM> may be a fluorescent layer.

In some embodiments of the present invention, the component <NUM> is, or is part of, a light switch or a door handle, especially a light switch, which are examples of components which are typically touched by different persons in e.g. a hospital or laboratory environment.

Claim 1:
A component (<NUM>) comprising:
a substrate (<NUM>) of a plastic material; and
an antibacterial flexible film (<NUM>) adhered to a top surface (<NUM>) of the substrate by a moulding process;
wherein the component further comprises a light source (<NUM>/<NUM>) such that the film is arranged to emit light having antibacterial properties from said light source;
characterized in that
the light source is arranged to emit visible light having a wavelength within the range of <NUM> to <NUM>.