MARKING APPLICATION METHOD

This invention concerns a method of applying a marking, and particularly a method of applying a marking onto antimicrobial coated material, and especially coated metal, glass or plastics material.

In this specification the term "marking" is to be understood as covering, inter alia, a decoration, pattern, image, colour, wording, logo or other which may be applied on to a surface.

Antimicrobial coated steels have been in use for some time. With for instance the advent of MRSA, the use of such materials has increased significantly. One area where this use has grown significantly is in kitchen implements and appliances. It is often wished to decorate or otherwise mark such steel, with for instance to a trade mark or other indication. However, if a marking is simply printed or painted on the coating, this will sit on the surface thereof and interfere with the coating's performance and properties. Antimicrobial coatings are also provided on other materials such as glass or plastics material, for use in the home, kitchens or medical situations.

Anti graffiti coatings are used in a wide range of applications. Such coatings readily permit markings thereon to be wiped off or removed with one of a selection of solvents. This can mean that it is difficult to satisfactorily decorate or mark items or structures with such coatings.

According to the present invention there is provided a method of applying a marking onto a coated substrate , the method including locating on a carrier mark material to be applied onto the substrate, the mark material being of a type which sublimes, bringing the carrier against the coated substrate such that the mark material is in contact with the coated substrate, applying heat such that the mark material sublimes to a gas, and retaining the

carrier against the substrate until the mark material in gaseous form has moved from the carrier and entered the coating on the substrate.

The carrier may be a carrier film or could be paper. The mark material may be a disperse dyestuff. The mark material may be initially printed onto the carrier, and may be printed by any of inkjet, digital, electrostatic, screen, flexo, offset, or Gravure printing processes.

The substrate may have an antimicrobial coating.

The antimicrobial coating may include an active material within a host material. The active material may include silver, and may include titanium dioxide and silver chloride. Alternatively the active material may be organic.

The host material may include any of polyester, polyester resin, polyether sulphone (PES) resin, PU (polyurethane), or PU copolymers.

Alternatively the substrate may have an anti graffiti coating.

The coating may be polyester based.

The coating preferably includes greater than 80% polyester.

The coating may be in the form of a powder coating.

When the carrier is brought against the substrate, sufficient pressure is preferably applied to the carrier to substantially evacuate any air from between the carrier and the substrate.

The carrier is preferably brought to a temperature of greater than

18O ⁰ C to cause sublimation of the mark material.

The substrate may comprise a metal which may be any one of steel, aluminium, copper or brass. The metal may be a ferritic metal or may alternatively be a non-ferritic metal.

5 The substrate may comprise glass or plasties material.

The carrier is preferably retained against the substrate for greater than 15 seconds, and desirably greater than five minutes.

I O In one arrangement the method is carried out in an enclosure at reduced pressure.

The invention also provides a marked coated substrate, the marking on the substrate having been applied by a method according to any of the 15 preceding fifteen paragraphs.

The substrate may be any of metal, glass or plastics material.

Embodiments of the present invention will now be described by way of 0 example only.

In a first example stainless steel is slit down to a dimension of 720mm. This is then brushed to provide polishing to achieve a "scotch bright finish". The steel is then painted with an antimicrobial coating in the form of titanium 5 dioxide and silver chloride in a clear polyester host. The painted steel is surface cleaned, cured and a protective film applied. If required an adhesive tape can be applied on the reverse.

A marking is then applied to the coated steel as follows. An

30 appropriate marking of a disperse dyestuff is inkjet printed onto a plastics material carrier film. The film is located against the coated steel with the

marking in contact therewith. This may be carried out on a flat bed with the carrier above or below the steel.

Sufficient pressure is applied to remove any air from between the carrier and the steel. Heat is applied to bring the temperature of the marking on the carrier to around 21O ⁰ C. The disperse dyestuffs of the marking sublime and the marking passes into the antimicrobial coating, beneath the surface thereof. The carrier film is retained against the steel during heat application for around three to five minutes or more, to ensure that all of the marking has sublimed into the coating.

There is thus described a method of applying a marking onto antimicrobial coated steel. This provides a required marking which could be a decoration, trade mark, wording or other indication, but which marking is located within the coating so as not to affect the performance or properties thereof. The marking is also therefore durable, being as durable as the coating within which it is held.

In a second example similarly prepared steel is coated with an anti graffiti coating. The coating is reinforced polyurethane such as lnterpon EC available from Akzo Nobel. The coating is applied manually or automatically using electrostatic spray equipment, with excess material being reclaimed and recycled. Such a coating is suitable for outdoor use in architectural applications, and readily permits graffiti to be removed by wiping or appropriate solvents. A marking can then be applied as described above for decoration, to provide an indication or signage or otherwise.

The invention could be carried out on a polyester based anti graffiti coating, with greater than 80% polyester.

It is to be realised that a wide range of other modifications may be made without departing from the scope of the invention. For instance the

invention could be used with coated metal substrates other than steel, and the substrates could be glass or plastics material. A wide range of different markings can be used, and different temperatures and retention times may be required to provide sublimation of these materials into the coating.

The marking may be differently applied to the backing material, and different printing techniques such as digital, electrostatic, screen, flexo, offset or Gravure could be used. It may be that the marking is applied to the carrier material other than by printing. The carrier material could be other than plastics film, and could be paper.

Any antimicrobial coating may include a different active silver agent, or may include an organic active agent. The host material of the coating could be or could include a polyester resin, polyether sulphone (PES) resin, PU, or PU copolymer.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.