The present invention relates to temporary tattoos and in particular, but not exclusively, to a method of manufacturing an ‘on demand’ temporary tattoo assembly for applying a temporary tattoo to the skin of a user.

Temporary tattoos are typically printed in large quantities on sheets of paper, plastic films, or combinations of the two. Paper is generally preferred because it is better for printing and processing. This backing paper is coated with a variety of materials using spraying or dipping methods. The coatings can be processed to a uniform thickness by passing the coated paper through a series of rollers outfitted with a knife which evenly spreads the liquid. The paper can then be passed through a heated tunnel to accelerate drying. The first coating that is applied is typically a sizing agent which modifies the paper's stiffness and texture. The next layer is a non-stick silicone release coating which helps the image separate from the backing paper when being applied to a user’s skin. A transfer film is then coated on top of the silicone layer. This film is the layer that the image is printed upon and is typically composed of gelatine or other polymeric materials, such as polyvinyl alcohol or polyvinyl pyrrolidone. These materials are designed to be strong enough to adhere to the backing paper during printing yet flexible enough to be easily released during application. Upon drying on the skin, the film should adhere tightly and smoothly to maintain the image quality.

A known problem with temporary tattoos is image degradation which can occur as a result of motion, expansion, and contraction of the skin, all of which cause tiny fractures in the image film layer. Even though the film remains adhered to the skin, the image quality is severely reduced due to the visible cracks and creases. Known attempts to address this problem use alcohol soluble dyes, water insoluble dyes and a special transfer solution to help maintain the integrity of the transfer film. US4,594,276 describes producing an image on one side of a translucent substrate and applying a pressure-sensitive adhesive on the other side of the substrate with a release layer thereon to allow the tattoo to be adhered to the skin for longer periods of time with minimal loss of image quality. Conventional temporary tattoos are typically produced by screen printing or lithographic printing which require relatively high set-up costs so are only cost effective for longer runs of around 100 units or more.

When producing ‘on-demand’ for smaller quantities or even single designs, it is not cost effective and commercially viable to use screen or lithographic printing, so laser or inkjet printing is typically used. However, each individual design must be either manually cut out from a sheet comprising of multiple tattoos using scissors, or the tattoos are supplied fully pre-cut as separate units which creates a significant problem for the manufacturer, trying to keep track of each design which is small and fiddly and ensure the correct design goes to the right customer. Having to cut out a tattoo from a sheet is both time consuming and fiddly for the user, particularly when the edges of the image are relatively intricate. Furthermore, the manually cut edge of the transfer film on which the image is printed, is generally jagged and the distance between the image and the manually cut edge of the release film is generally non-uniform which results in excessive clear transfer film and adhesive around the image which is particularly evident when on the skin. This makes the product look unrealistic, and of relatively low quality. Peeling the release layer from the front of the tattoo to reveal the adhesive is also inconvenient and can result in damage to the edges of the tattoo as well as the tattoo image itself. As stated previously, whilst fully pre-cut tattoos may be more convenient for the end user, manually sorting and matching tattoos to orders is time consuming and unsustainable for large scale production, and the risk of damaging the edges of the tattoo when peeling off the release layer still exists.

It is an aim of certain embodiments of the present invention to provide an improved ’on-demand’ temporary tattoo which is less complex and more sustainable to produce, particularly in relatively small or even single quantities, and which results in a more realistic tattoo without excess material and adhesive along with untidy edges.

It is an aim of certain embodiments of the present invention to provide a method of manufacturing temporary tattoos in sheet form wherein the sheet is partially pre-cut for easy removal of each tattoo therefrom by the end user, whilst ensuring each tattoo is secured to the sheet before removal by the end user to prevent individual tattoos being lost or mixed-up during manufacture, transit, display or storage, for example.

According to a first aspect of the present invention there is provided a method of manufacturing a temporary tattoo, comprising: providing a substantially translucent substrate having a first side and a second side; printing a predetermined tattoo design on the first side of the substrate; adhering a backing release paper to the second side of the substrate; cutting through the substrate and around the tattoo design at a predetermined distance therefrom, whilst leaving the backing release paper intact, to thereby define a first substrate region including the tattoo design separable by a user from a second substrate region; disposing an adhesive layer on the first side of the first substrate region and the second substrate region; and applying a release film on the adhesive layer.

Optionally, the method comprises processing image data associated with the design to determine the predetermined distance and a cutting path for a cutter to follow when cutting through the substrate and around the tattoo design.

Optionally, the method comprises: feeding the substrate and the backing release paper between a first pair of opposed laminating rollers to adhere the backing release paper on the second side of the substrate; and taking up the substrate and backing paper combination in roll form.

Optionally, the substrate and backing release paper are fed from a first feed reel and a second feed reel respectively, and the substrate and backing paper combination is taken up in roll form. Optionally, the method comprises feeding the substrate and backing paper combination through a cutter to cut the substrate and around the tattoo design at the predetermined distance therefrom whilst leaving the backing release paper intact.

Optionally, the substrate and backing paper combination is fed from a cutter feed reel and the cut substrate and backing paper combination is taken up in roll form on a cutter take-up reel.

Optionally, the method comprises feeding the cut substrate and backing paper combination between a second pair of opposed laminating rollers to dispose an adhesive layer on the first side of the substrate and over the printed tattoo design.

Optionally, the cut substrate and backing paper combination is fed from a third feed reel, the adhesive layer is fed from a fourth feed reel, and the cut substrate, backing paper and adhesive combination is taken up in roll form.

Optionally, the method comprises simultaneously feeding the release film through the second pair of opposed laminating rollers to apply the release film on the adhesive layer.

Optionally, the release film is fed from a fifth feed reel and the tattoo assembly is taken up in roll form downstream of the second pair of opposed laminating rollers.

Optionally, the substrate comprises a substantially translucent waterslide paper.

Optionally, adhering the backing release paper to the second side of the substrate comprises using a pressure sensitive adhesive having a peel strength of 80g/50mm - 120g/50mm (20min dwell time, FTM1) and/or 160g/50mm - 240g/50mm (24hr dwell time, FTM1).

Optionally, the peel strength is 100g/50mm (20min dwell time, FTM1) and/or 200g/50mm (24hr dwell time, FTM1). Optionally, the method further comprises heating a skin-safe ink or toner after printing the tattoo design on the substrate.

Optionally, heating comprises directing infrared radiation towards the substrate to heat cure and dry the ink or toner.

Optionally, the method comprises removing the backing release paper after applying the release film.

According to a second aspect of the present invention there is provided a temporary tattoo assembly comprising: a substantially translucent substrate having a first side and a second side; a predetermined tattoo design printed on the first side of the substrate; an adhesive layer disposed on the first side of the substrate and over the printed design; and a release film applied on the adhesive layer, wherein the substrate is pre-cut around the tattoo design at a predetermined distance therefrom to thereby define a first substrate region including the tattoo design separable by a user from a second substrate region.

Optionally, the first substrate region is disconnected from the second substrate region by said cut.

Optionally, the substrate comprises a substantially translucent waterslide paper.

Optionally, the tattoo design is printed using a skin-safe ink or toner.

Optionally, the assembly comprises a backing release paper adhered to the second side of the substrate.

Optionally, the backing release paper comprises an adhesive coating having a peel strength of 80g/50mm - 120g/50mm (20min dwell time, FTM1) and/or 160g/50mm - 240g/50mm (24hr dwell time, FTM1). Optionally, the peel strength is 100g/50mm (20min dwell time, FTM1 ) and/or 200g/50mm (24hr dwell time, FTM1).

According to a third aspect of the present invention there is provided a method of applying a temporary tattoo to skin of a user, comprising: peeling a first substrate region of a substantially translucent substrate away from a release film applied to an adhesive layer disposed on a first side of the first substrate region and a second substrate region of the substrate, wherein the first substrate region includes a predetermined tattoo design printed on the first side thereof and the substrate is pre-cut around the tattoo design at a predetermined distance therefrom to define the first substrate region separable by a user from the second substrate region; and adhering the first substrate region including the printed tattoo design to skin of a user.

Optionally, the method comprises removing a backing release paper adhered to a second side of the substrate to reveal the tattoo design printed on the first side of the substrate.

Description of the Drawings

Certain embodiments of the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 illustrates an exploded schematic view of a temporary tattoo assembly according to certain embodiments of the present invention;

Figure 2 illustrates the apparatus for laminating the backing release paper on the second side of the substrate of the temporary tattoo assembly of Figure 1 ;

Figure 3 illustrates the apparatus for cutting the substrate of the temporary tattoo assembly of Figure 1 ; Figure 4 illustrates the apparatus for laminating the release film on the first side of the substrate of the temporary tattoo assembly of Figure 1 ; and

Figures 5a to 5c illustrate the steps of applying a temporary tattoo to skin of a user according to certain embodiments of the present invention.

Detailed Description

As illustrated in Figure 1 , a temporary tattoo assembly 100 according to certain embodiments of the present invention includes a substantially translucent waterslide paper substrate 102 comprising a first side and a second side and an ink or toner receptive coating on at least the first side. By ‘translucent’ it is meant that at least 30%, and preferably at least 50% or 75%, of incident visible light is transmitted or that at least 80% of light within a 50nm band is transmitted through the substrate when adhered to a surface without perfect optical clarity through the substrate. Preferably, the surfaces of the substrate are non-reflective and do not have a shiny appearance. Furthermore, the texture of the substrate is preferably similar to that of skin, i.e. not perfectly smooth, and have a similar sheen to thereby blend in with the skin. The waterslide paper substrate is conventional and may, for example, comprise a polymeric fibrous film or web of polyester, polyvinyl resin, cellulose acetate, polyamides, or the like, having a coating of, for example, dextrose to allow the substrate to slide away from an adjacent layer when subjected to water.

A predetermined tattoo design 104 is printed on the first side of the substrate 102 and a backing release paper 106 is adhered to the second side of the substrate 102. The backing release paper comprises cellulose and polyethylene, for example, and is for example a 70-140gsm kraft paper with a silicon backing. Aptly, an aqueous acrylic pressure sensitive adhesive of a microsphere nature is coated on the nonsilicone side of a 70gsm silicon coated kraft release liner. Aptly, the 70gsm backing paper has a thickness of around 94 microns +/- 7 microns and the release liner is 135gsm and has a thickness of around 132 microns +/- 7 microns. Peel strength tests were carried out using the Finat Test Method 1 (FTM1 ) wherein the average force over a distance of 50 mm is measured as the samples are peeled from polished stainless-steel plates at an angle of 180°, at a test speed of 300 mm per minute, and after intervals of 20 minutes and 24 hours. The optimum peel strength results for this particular application have been found by the applicant to be 100g/50mm (20min dwell time) with a suitable range of around 80g/50mm - 120g/50mm, and 200g/50mm (24hr dwell time) with a suitable range of around 160g/50mm - 240g/50mm. These peel strengths have been found by the applicant to be particularly suitable for holding the printed substrate 102 in place when cut to avoid the tattoo design falling off the roll, as described further below, whilst allowing the backing release paper 106 to be efficiently peeled off the second side of the substrate 102, along with the adhesive coating, without tearing the backing paper 106 or the substrate 102 and/or pulling the substrate with it when the user separates the two components in use before applying the tattoo to their skin.

An adhesive layer 108 is applied to the first side of the substrate 102 and over the design 104 printed thereon, and a clear release film 110 is located on the adhesive layer 108. The adhesive is a pressure-sensitive adhesive comprising an acrylic polymer and is skin-safe, and the release film comprises polyethylene terephthalate. Aptly, the tattoo design 104 may be any form of printable graphic or artwork, such as an image, sketch, photograph, logo, name, word/s, number/s, or the like, and may be printed on the substrate using skin safe ink or toner by any suitable printing method, such as inkjet or laser printing or the like.

A method of manufacturing the tattoo assembly 100 according to certain embodiments of the present invention will now be described. Firstly, one or more transparent (no background colour) bitmap-based images in, for example, .png format are input to a program executable by a computer which is configured to prepare each image for printing by individually tracing the designs, adding image padding (space around the design), and applying a vector cutting path around each design. This processed file is then added to a pre-designed printing page template where each file is laid out ready for printing and all of the cut data for the page is combined into a single cut file to be used by the cutter. This cut path processing technique according to certain embodiments of the present invention desirably enables intricate and close cutting around the design to minimise the visible edge region of the tattoo surrounding the printed image and in turn improve the realism of the tattoo. The program is also configured to recognise different elements in the image file which are separate by a predetermined threshold distance to thereby avoid generating ‘compound’ cut paths, e.g. holes in shapes, which could create a tattoo that is difficult to apply.

The individual tattoo designs are then printed onto the first side of the waterslide substrate 102, preferably in roll form and suitable for inkjet or laser printing using skin-safe ink or toner, such as food dye or vegetable based ink for example. The designs may all be the same or may comprise different designs. Printing the designs on a roll of the waterslide substrate allow for large ‘on-demand’ print runs of lots of individual designs which would not be sustainable if the substrate was in individual sheet form. During significant research and development, the applicant identified skin-safe inks, such as food dye or vegetable based inks, had a much longer drying time than traditional printing inks which meant the printed designs would smudge easily post-printing and/or imprint themselves on the reverse of the substrate paper when wound on the take-up reel downstream of the printer. Aptly, infrared heating is used to dry the ink and infrared lamps are provided between the printer and the takeup reel, such as mounted proximal to the output region of the printer, to heat and cure the ink after printing and before the printed substrate is wound on the take-up reel.

As illustrated in Figure 2, the backing release paper 106 is then applied to the second side of the printed substrate 102 by a first cold laminator 200. As described above, the inner surface of the backing release paper 106 is coated with a pressure sensitive adhesive. As illustrated, the printed substrate 102 which is mounted in roll form on a first feed reel 202 is fed between a pair of opposed rollers 204,206. At the same time, the backing release paper 106 which is mounted in roll form on a second feed reel 208 is fed between the rollers 204,206 such that the backing release paper 106 is adhered to the second side of the printed substrate 102. The combined layers 102,106 are then taken up in roll form on a laminator take-up reel 210 ready for cutting.

As illustrated in Figure 3, the printed substrate 102 laminated on its second side with the backing paper 106 is then fed from a cutter feed reel 302 through a reel-to-reel cutting machine 300 and taken up on a cutter take-up reel 304. The laminated substrate 102,106 is fed back and forth with respect to a laterally moveable cutting head of the cutting machine 300 which is configured to cut through the printed waterslide substrate 102 and continuously around each design in response to the cut file sent to the cutting machine 300, whilst leaving the backing release paper 106 fully intact. This defines a first substrate region including the tattoo design and a second substrate region disconnected from and surrounding the first substrate region. Alternatively, the substrate may be cut intermittently around the tattoo design to leave one or more frangible regions connecting the first substrate region to the surrounding second substrate region which the user fractures when removing the first substrate region in use, as described further below. Desirably, the/each printed tattoo, i.e. the first substrate region including the tattoo design, is held in place on the roll for further processing, which is particularly desirable for large scale/mass production, and also on the backing paper for transit, display, storage, etc. before being used. Retaining the printed tattoo/s (first substrate region/s) on the uncompromised backing paper 106 also makes handling and applying the tattoos much easier, particularly if the tattoo designs are relatively intricate and small which otherwise would be difficult to handle and apply if loose.

As illustrated in Figure 4, the printed and cut waterslide substrate 102, including the backing paper 106 laminated to the second side of the substrate, which was taken up in roll form downstream of the cutting machine 300 is then fed from a third feed reel 402 through opposed rollers 404,406 of a second cold laminator 400. At the same time, the adhesive layer 108 is fed from a fourth feed reel 408 and applied to the first side of the substrate 102 on which the tattoo design has been printed. By using a laminator and having a roll of printed designs instead of pre-cut sheets, it enables the adhesive to be applied evenly and neatly and avoids any air bubbles or accidentally introduced creases which can occur if the adhesive is applied by hand. Aptly, the adhesive 108 is a skin-safe adhesive. Simultaneously, the release film 110 is applied to the adhesive layer 108 from a fifth feed reel 410 and a release liner 112 is taken up on a release liner take-up reel 412. The adhesive is gel-like and is sandwiched between two liners to allow is to be rolled without sticking to itself. One of the release liners 112 is removed and taken up on the release liner take-up reel 412, whilst the other liner is left on. The finished tattoo assembly 100 is taken-up in roll form downstream of the rollers 404,406 on a finished take-up reel 414. As illustrated in Figure 5a, each tattoo assembly 100 may be provided separately, i.e. each separate assembly includes a single tattoo design. Each separate tattoo assembly may be sold separately or collectively in a pack. Alternatively, a number of the same or different tattoo designs may be sufficiently spaced apart and pre-cut on the same sheet of backing release paper 106 to form a tattoo assembly 100 comprising a plurality of pre-cut tattoo designs. The backing release paper may remain for the user to remove or may be removed prior to being supplied. Desirably, a key function of the backing release paper is to allow the substrate to be cut before the skin adhesive layer is applied whilst ensuring each cut-around design remains secured to the roll for further processing during manufacture.

To apply the chosen tattoo to the user’s skin, the user first peels off the backing release paper 106 from the second side of the waterslide substrate 102 of the tattoo assembly 100 (if the backing paper has been left on at the end of the manufacturing process) to reveal the tattoo design printed on the first side of the substrate 102. The pre-cut tattoo can then be peeled away from the release film 110 which was applied to the skin-safe adhesive layer 110 disposed on the first side of the substrate 102 and over the tattoo design 104 ink or toner printed thereon. The tattoo can then be applied to the user’s skin.

Certain embodiments of the present invention therefore provide a temporary tattoo that requires no cutting by the user and eliminates excess film and adhesive regions surrounding the tattoo design. The method of manufacture and tattoo assembly according to certain embodiments of the present invention are particularly suitable for manufacturing ‘on-demand’, custom manufacturing, or cloud manufacturing, wherein products are only manufactured when needed and in required quantities. This is in contrast to traditional temporary tattoo manufacturing in which products are manufactured in large quantities and stored in facilities until they are sold, distributed, and delivered. In turn, the tattoo is visibly substantially more realistic than conventional temporary tattoos and has a much higher quality in terms of appearance and user experience. Application of the tattoo is made much easier for the user as there is no fiddly transparent film to peel away. The method of manufacturing the tattoo assembly according to certain embodiments of the present invention allows the same to be efficiently scaled up for large/mass ‘on-demand’ production, particularly in view of cutting the printed substrate whilst leaving the backing paper intact. Furthermore, cutting the substrate before applying the skinsafe adhesive to the first side thereof and over the printed design desirably avoids the cutter being exposed to the relatively thick and messy adhesive and in turn extends the service life of the cutting head and reduces downtime for maintenance, etc.