PRINTABLE ADVERTISING AND DISPLAY SUPPORTS

[1] This invention relates to printable advertising and display supports, for example for use in external advertising signs, billboards, posters and the like, as well as for internal displays, for example in-store advertising banners or posters, point-of-sale displays, and informational signage, particularly temporary signs and placards.

[2] Although 'high tech' advertising structures, such as large-scale electronic screens, back projection arrangements and electronically driven displays, have in recent years secured a certain amount of the advertising and display market, by far the majority of advertising and display consists of some form of 'message' which may be purely pictorial, verbal, or a combination of the two, applied to a paper, textile or plastics- based structure by an appropriate printing method.

[3] Much advertising and display material is ephemeral, and accordingly the advertising industry generates substantial quantities of display material which is needing to be regularly disposed of. Although paper, textile and plastics materials can be recycled in appropriate circumstances, they are rarely designed to be so.

[4] Various plastics-coated or laminated textile materials are known for use when printed as banners or other display sheets. For example US-B-6503977 describes coatings for textiles to produce printable substrates and DE 202006012870U 1 describes a composite material for decorative and advertising purposes. DE 29615909U1 describes PVC-coated fabrics for use as display panels while JP-A- 1025976 describes cloth sign boards. None of these disclosures avoids the use of eco-unfriendly materials, and some of the materials used are almost non-biodegradable, at least not on a useful timescale. Some take years to degrade, even in favourable conditions promoting bio-degradation. Commercially available printable coated fabrics use either polyester- or acrylic-based coatings which, while rendering the cloth printable, are simply non-biodegradable.

[5] The present invention seeks to provide advertising and display media which are inherently more eco-friendly and, in particular, which are adapted for biodegradation in a rapid and eco-friendly fashion.

[6] According generally to the present invention, there is provided printable advertising or display support material consisting of a natural fibre-based fabric and a

strengthening material applied thereto, in the form of a roll and characterised by its printable surface(s) being substantially free of upstanding fibres and outer material being compostable as defined in EN 13432:2000.

[7] The principal requirements for compostability set out in EN 13432:2000 are:

[8] Disintegration :

[9] 90% disintegration must be achieved in an aerobic composting environment within 12 weeks. When compost is screened at the end of the 12 weeks, less than 10% by weight of the original dry weight of the material should remain on a 2 mm screen.

[10] Biodegradabilitv :

[11] In watery medium. At least 90% of the organic material is converted into CO ₂ within

6 months. (This is normally not an issue for natural materials without chemical modifications on the condition that no organic additives are present in a concentration above 1% and the total content of organic constituents without determined biodegradability is below 5%).

[12] Heavy metal and other toxic or hazardous substances :

[13] The various thresholds for heavy metal etc. contents set out must not be exceeded.

[14] Ecotoxicity :

[15] The germination rate and plant biomass of the compost produced by composting the material of the invention should be more than 90% of the corresponding parameters obtained using blank compost.

[16] The strengthening material may take the form of a coating designed to increase the tensile strength and dimensional stability of the textile fabric.

[17] The natural fibre-based textile fabric is preferably exclusively made of natural fibre, for example jute, hemp, calico, hessian, cotton, bamboo, ramie, nettle or linen. Textile fabrics may be made from all of these materials by a variety of known techniques, though, for the purposes of the invention, the preferred method of manufacture is by weaving. The thickness, basis weight, texture and other properties may be varied widely, with thinner, lighter, finer textured materials generally being preferred for back-lit displays, while heavier coarser texture materials may be used to provide a textured surface to the printed display product, or where a degree of opacity is desired.

[18] Preferred textile fabrics are plain woven organic cotton fabrics of basis weight range

100 to 150 gsm, and jute hessian fabrics of warp and weft thread count 17 x 18 to 12 x

13 basis weight range 250 to 345 gsm.

[19] In terms of the strengthening material, the preferred method is to apply a layer of natural latex to the textile material, either from one side or both sides. It is often desirable, prior to coating, to make a series of cuts in the fabric selvedge at an angle of 90 degrees to the material edge, usually about 25 mm in length, at distances between 15 cm and 30 cm dependent on material used. Such cutting relieves the selvedge tension to prevent any irregular tensioning during the application of the strengthening material. If this is not done then the material can have mixed tensioning after the application of the strengthening material even when the selvedge is removed which can give rise to problems during the printing of the material. The coarser the material, the less the need for such cuts as the material is more rigid. The preferred method of applying such strengthening material is to start by heating the latex and mixing in natural minerals to produce the desired colour and then to roll the latex into rough sheets. These rough latex sheets are then treated in a calendar machine to thin them to the desired thickness under heat and pressure between calendar rollers. Once the correct thickness and weight are achieved, the calendered sheet is pressed together with the natural fibre textile fabric using heat and pressure provided by heated rollers to bond them together. The bonded laminate is coated with potato starch as it comes off the machine to stop sticking, rolled and left to settle for a couple of hours. It is then re-rolled on to curing cores and placed in a heated oven to cure, e.g. for 3 to 5 hours at 115 to 125 ⁰ C. Once cured, the cores are taken out. The material is then re -rolled on to fresh roll cores and during this final rolling process, care is taken to ensure all the potato starch is removed and all loose fibres removed to avoid or minimise problems with ink jet printing, particularly head strike, when the product is printed.

[20] The strengthening material may be applied as an emulsion or solution. The

strengthening material should be one which bonds well to the fibres of the textile fabric and preferably is one which is absorbed between them to create a substantially more dimensionally stable and stronger sheet material. Also, it should preferably act, in combination with the particular method of application, to pull down any textile fibre projecting from the surface of the untreated textile material, so as to provide a surface finish substantially free of upstanding fibres which could cause problems when the material is printed, for example head strike in inkjet printing processes. One advantage of using natural latex as the strengthening material is that it provides dissipation of the heat generated during the print process, allowing the use of high temperature print curing, such as occurs in latex printing systems, and ensuring the material does not reach scorching or combustion temperature.

[21] Composite sheet materials consisting of a textile sheet and a strengthening or backing as just described tend not to be very white, but an increase in whiteness may be easily achieved if the backing material is itself rendered whiter by bleaching (using natural bleach materials so as not to compromise the compostability of the material) or by the appropriate admixture of whitening material, such as an environmentally friendly white dye or the composite sheet material may be subjected, prior to the application of the printing, to an overall whitening treatment, for example coating with a white reflective layer. If desired, in certain applications, the support material may be coloured other than white, for example by dyeing or pigmenting, provided that the dyes or pigments used have no adverse environmental effect.

[22] The material according to the present invention is presented in roll form, for example of standard size and length such as 30 metre rolls, 1200 mm wide. Care should be taken to ensure a clean finish, with the strengthening material covering the entire surface and the selvedges being clean cut from the remainder of the material, for example using a roll slitting machine, without leaving upstanding fibres.

[23] Using the approach of cutting the selvedge previous to the coating step and then

removing the selvedge after coating enables the final material to adopt a constant tension/stretch behaviour during the subsequent printing step when the material of the invention is put to use.

[24] The printing of the advertising message, pictorial display or design on to the

composite sheet material described above may take place by any appropriate method, inkjet printing being preferred. We have found that best results are obtainable with commercially available large format flat bed printer systems such as the Vutek range of UV printers and commercially available roll-to-roll inkjet printers, such as the Hewlett Packard range of latex printers. Provided that they do not adversely affect compostability, UV curable inks are preferred by many printers as they enable rapid print production. Sepia X inks may also be used. In all cases, the inks used are preferably made wholly or predominantly of environmentally friendly materials as this assists the biodegradability of the final advertising or display item. The dissipation of heat provided by the latex- strengthening material enables high temperature printing processes to be used without problems arising.

[25] If desired, other or further protective coatings may be applied, for example coatings to enhance or improve printability (particularly by pulling down to the surface any protruding fibres), coatings to improve surface gloss, coatings to impart fire-resistance and coatings designed to render the viewed surface water resistant. This last is of particular importance in the case of outdoor advertising. Again, the materials used for any such further coatings should not adversely affect the compostability of the material. Application of such coatings may be by coating or spraying, by hot knife application, or by using a gravure coating technique. In this last case, a liquid coating material is applied under heat to an engraved drum. The material lies in depressed areas on the surface of the drum and may then be deposited on to the receiving material by rolling contact of the material with the drum surface. The gravure drum surface may be engraved to different depths to provide different thicknesses of coating e.g. 25 gsm, 50 gsm. A preferred coating weight of 50 gsm provides excellent coating coverage in manufacturing materials according to the invention. The application of such a coating also reduces the stretchability of the material, which also assists the printing process. A particularly preferred class of enhancement coating is bioresin coatings, for example C2410 UK DaniMer Scientific LLC, which can be applied by slot coating at a coating weight of e.g. 50 gsm to provide a coating which provides a high quality print.

[26] The advertising and display materials described above may be mounted in the desired position on conventional supports for such advertising and displays, for example wooden hoardings or appropriate display stands or frames to which the advertising or display item may be clipped or fixed using biodegradable adhesives or biodegradable adhesive tape materials (which will usually remain adhered to the advertising or display item when it is disposed of, for instance in the case of removable adhesive liners).

[27] A major advantage of the advertising and display structures in accordance with the present invention is that, at the end of the time for which the advertisement or display is allotted, the composite sheet material which has formed the advertisement or display may be simply removed and easily disposed of without constituting a substantial burden on the environment. In particular, in preferred embodiments according to the invention, the entire material is simply and rapidly biodegradable, which

biodegradation process may take place rapidly and in an environmentally friendly fashion to leave little in the way of 'carbon footprint'. The preferred method is to compost the material, either at ambient temperature or with added thermal input using a suitable composting plant or installation. Using vermicompost systems, we have found that over 90 percent of the material according to the present invention can be composted within 14 days.

[28] The present invention may be applied over a wide range of sizes for advertising and display products. Depending upon the nature of the support and the size chosen, the degree of strengthening imparted to the natural fibre-based textile material may be adjusted so as to impart sufficient strengthening for the intended service life, but not to over- strengthen the material which would be pointless.

[29] The following examples will serve to illustrate the invention.

[30] EXAMPLE 1

[31] External Advertising Hoarding

[32] An external advertising hoarding was provided with an advertising message

consisting of a standard number of standard size sheets by adhering each sheet to the hoarding (or to the previous advertisement carried by the hoarding) using a

biodegradable glue (Auro® Natural Resin Universal Adhesive 380).

[33] Each sheet was cut from a roll of finely woven hessian cloth of thread count 14415 and basis weight 305 gsm bleached to white, on to which natural latex rubberising coating, also bleached to white, had been applied at a coating weight of 250 gsm, using a calendaring process.

[34] The individual sheets were then printed with part of the overall advertising design using a UV flatbed digital printer (type Vutek®) which was computer controlled and where the individual 'tiles' of the original computer-generated design were printed on to the respective individual sheets.

[35] At the end of the advertising campaign, the sheets were simply pulled off from the advertising hoarding and composted. [36] EXAMPLE 2

[37] In- store Suspended Displays

[38] 100% organic cotton plain weave fabric of basis weight 125 gsm were roller coated on one side with a strengthening solution consisting of a natural latex rubber dyed to match the fabric colour, at a coating weight of 245 gsm.

[39] The resulting fabric could be ink jet printed, either on the side bearing the coating or on the fabric side with a high definition logo, legend or advertising message of pictorial, verbal or mixed pictorial and verbal nature, using an HP latex ink jet roll- to-roll printer, and individual display units then cut from the printed roll.

[40] The edges of each sheet were then adhered using a biodegradable adhesive (Auro®

Natural Resin Universal Adhesive 380) to a rectangular card frame made of recycled cardboard 2 mm thick. Two holes punched in the corners of the frame allowed the placard thereby created to be suspended from a ceiling in a supermarket or like store environment using the customary suspension apparatus.

[41] Numerous variations may be made to suit particular circumstances, but, in all cases, the advertising and display material, once it has served its purpose, may be easily and rapidly biodegraded by composting with minimal environmental impact. The present invention embraces not only the material itself, as defined above, but methods for making it and its use in advertising, as set out in the appended claims.