DESC:Field of The Invention
The present invention relates to a package comprising pattern and/or text printed with specially formulated UV sensitive ink. More particularly the invention relates to package with printed text and / pattern such that the ink has pigments and is suitable for any type of printing e.g. off set printing and the printed matter is visible with good glow upon UV exposure. The package is printed with single or multiple hits of the UV Sensitive Visible Ink. The invention also describes method of printing on the package with the said ink so as to be visible and glow on UV exposure.

Background of the invention
Images or printed matter on the packages, containers and display units for providing information to the end users about the product are known for decades and pressroom printing has been a place to create artworks on packaging materials. The printings are either carried out by conventional pressroom printing processes like Gravure, Offset, Flexography or Screen Printing or by digital printing. However, the known printing processes either use inks that are visible in normal light conditions or inks that may be UV reactive and are cured by UV exposure.

US 6102536A and US 135654A disclose a method and apparatus for printing digital graphic images directly onto web of packaging material or bottles. The method of printing on web is provided in which an electronically storable and retrievable digital image is generated followed by transferring the image to a printing site and printing the image on to the web of packaging. The ink as disclosed in this art is provided as a UV reactive ink wherein it can be cured by exposure to UV after the step of printing. The printing step could be performed concomitantly with the forming, filling and sealing of the package by placing the packaging machine at the print site and it further discloses that the process may include two or three colors print-heads.

US2012194622A1 discloses a method of printing a pattern on electrical circuit by using an UV curable ink wherein the ink is curable by exposing to UV radiation. ‘622 further teaches the method to expose/illuminate the printed pattern using monochromatic UV radiation or multiple wavelengths that differ from each other and may be selected such that an uniform curing of pattern is obtained. ‘622 also relates to a system that may include a printing module, arranged to a jet on an electrical circuit, an UV curable ink and a curing module. It provides a system that may include the necessary elements for using UV LEDs and chemical compositions specifically formulated for use with UV LEDs such that these LEDs may be used in curing process.

Thus the prior art teach the digital printing processes using UV reactive inks that are cured by exposing to UV light. However, none of the prior arts disclose whether the printed matter would be visible under conditions where in normal light conditions are unavailable. Hence, there is a need to provide a package comprising pattern and/or text printed on that are visible under low light conditions for e.g. Hotels, Restaurants and Cafeteria where the product graphics and brand name are not clearly visible without interfering with the ambience of the place with low light.

Object of the invention

It is an object of the invention to overcome the drawback of the prior arts.
It is another object of the present invention to provide a package comprising pattern and/or text printed with UV sensitive ink formulation wherein the printed matter is visible with good glow upon UV exposure.

It is yet another object of the present invention that the said UV sensitive ink is suitable for any type of printing such that the printed matter is visible with good glow upon UV exposure.

It is the further object of the present invention to provide a package comprising pattern and/or text printed with specially formulated (novel) UV sensitive ink having pigments such that the printed matter is visible with good glow upon UV exposure under low light condition without affecting the low light ambience of a place.

Summary of the invention

A process of printing on a packaging with UV sensitive ink comprising the sequential steps of.
(i) printing a graphics and elements on the packaging by processes selected from Offset, Gravure, Flexography, Screen and Letter-press such that the deposition of conventional ink is between 0.2 to 12 GSM;
(ii) printing selected areas on said packaging through a printing processes (e.g. offset printing) with the UV sensitive ink comprising additives/ pigments such that the deposition of conventional ink is between 0.2 to 12 GSM;
wherein said UV sensitive ink comprises 20 to 25% by weight UV monomer (low molecular weight), 40 to 45% by weight UV Oligomers (high molecular weight), 20 to 25% by weight Pigments, 5 to 10% by weight Additives.

Detailed description of the invention

Ultra Violet (UV) lights are a good source of focussed localised light which helps to maintain the low light ambience of a place. The present invention relates to a package comprising pattern and/or text printed with specially formulated (novel) UV sensitive ink wherein the said ink is suitable for any printing type e.g. offset printing such that the printed matter is visible with good glow upon UV exposure.

The UV sensitive ink of the present invention contains special UV sensitive additives in the formulation which absorb light in the ultraviolet region and reflect it in the visible light. When UV light is subjected on regions having the UV sensitive ink with the additives, those regions glow. The range of wavelength of UV light used for exposure and range of visible light wavelength for glow is 400 nm to 10 nm.
The ink has pigments which glow on exposure to UV light. The print specially provides attractive glow to the graphic/ text which thus stand out and is visible whenever UV light falls on the same. The pigments used in the ink are able to absorb the UV light and emit visible light. This makes the prints glow and visible under exposure toUV light and also highlight specific portions where the pigment is more. In case the pigment is evenly distributed the whole pattern glows evenly. In case depth of glow is required a thick print is provided so that the entire graphic glows. The pigments are capable of providing different hues and coloured glow on being exposure to UV to provide a multicoloured effect. The present inventors have found that in places where the lighting conditions are low for e.g. Hotels, Restaurants and Cafeteria the product graphics and brand name are not clearly visible. The packaging of the present invention is made visible with different sources of light, which are much localised so as to maintain the low light ambience of the place.

The novelty of invention lies in the ability of pigment to absorb light in the UV region and reflect in visible region. In conditions of low light where there are localised UV lamps/lights present, the pigmnets absorb uv lights and emits colours in visible spectrum which are visible as different colours to human eyes.

The process of using visible light or high energy electrons, UV energy, as opposed to thermal, evaporative or oxidative (air dry) cure to form a coating, film or ink is also known as “energy curing.” When it is related to radiation curing, there are two types are commonly used and they are through ultraviolet photons and electron beam (low energy electrons).

The present invention also provides method of printing graphic and/or text on packaging material. The graphic and text is printed by offset print on the package. The package surface is appropriately prepared for the offset print by conventional process.

The process of the present invention preferably comprises 2 stages of printing with UV sensitive ink on the packaging.

The two printing stages are sequential and are as follows: stage one, where the graphics and elements can be printed by any of the standard printing processes like Offset, Gravure, Flexography, Screen or Letter-press and the deposition of conventional ink on the substrates can be anywhere between 0.2 to 12 GSM. Stage two, where selected areas on the pack are printed through offset printing processes with the UV sensitive ink comprising additives/ pigmentsand the deposition of ink on the substrates can be anywhere between 0.2 to 12 GSM.

One of the features of the present invention is that the said UV sensitive ink with additives (or pigments) has been suitably formulated for the any kind of printing process e.g. offset printing with a good deposition of the ink. The compositions of the inks are as follows:

20 to 25% by weight UV monomer (low molecular weight), 40 to 45% by weight UV Oligomers (high molecular weight), 20 to 25% by weight Pigments, 5 to 10% by weight Additives (photo initiators – PI, e.g. surface & through photo initiators).

The concentration of inks having 20 to 25% of pigmentation in formulation gives the maximum impact. Concentration below this range does not give desired effects.

The UV monomer according to the present invention is selected from process coloured UV inks used for printing is isobornyl acrylates (monofunctional), triproylene glycol diacrylates (difunctional monomer), trimethylol propane triacrylate (trifunctional monomer) and the like.

The UV Oligomers is selected from process coloured UV inks used for printing is epoxy acrylates e.g. bisphenol A diglycidyl ether diacrylate, urethane acrylates.

Pigments according to the present invention are colouring agents that are fluorescent in nature (15 to 17%) and they are: cyan U1670, magenta U1688, yellow U1647, black U1669 and the like.

The ink composition can further comprise of Additives that are photo initiators (PI) found in the range of 1.5 % which can react only with UV-Vis energy and has a long shelf life.

Offset printing is a technique in which the inked image is transferred (or "offset") from a plate to a rubber blanket, then to the printing surface. The basic principle is based on the repulsion of oil and water theory, the offset technique employs a flat (planographic) image carrier on which the image to be printed obtains ink from ink rollers, while the non-printing area attracts a water-based film (called "fountain solution"), keeping the non-printing areas ink-free. The thickness of ink can be guided on press with digital control on press and by transfer of inks from blankets to plates. Further the thickness of ink is guided on press and is digitally controlled. Also, changes can be done in flow properties of inks for deposition as per requirement. It has been found that the thickness of inks plays a vital role in generating the final impact in UV light. Higher the thickness more will be the impact.

Offset printing process not only enable to print graphics on packs but also prints UV reactive Inks in full coverage or registered areas as per requirement. The deposition of inks can be controlled and inks can be applied through a single pass or through multiple passes for enhanced visibility and higher deposition.

Another feature of the present invention is that the package can be printed with two hits of the UV sensitive visible inkto obtain a good deposition of the ink on the substrate thereby provides a good glow and enhances the visibility of the printed matter on the package upon UV exposure under low light condition.

The printed package of the present invention is suitable for a product promotion in retail and other outlets, malls, hotels, restaurants and casinos where UV lights are present to create desired environments and also can be used as a covert anti-counterfeit feature in any FMCG products.
The present invention is now illustrated my way of non-limiting examples.

Example 1
The compositions of the inks are as follows:

comprises 20 to 25% by weight UV monomer (low molecular weight), 40 to 45% by weight UV Oligomers (high molecular weight), 20 to 25% by weight Pigments, 5 to 10% by weight Additives (photo initiators).

When the packaging material is printed with the present composition, and when exposed under UV light, it would glow and when the same placed under the normal light conditions, it does not appear visible to the user.

Example 2
The present invention will not work with any ink, which does not comprise of fluorescent ink and photo initiator of the specification

Example 3
The desired effect can be achieved through any of the printing process. However, in the present invention uses offset process. Each printing process has different deposition of inks. The details for which are enclosed below
Sno Process Deposition
1 Offset 1.5 to 1.75 gsm
2 Flexo 1.5 – 2 gsm
3 Gravure 2 – 3 gsm
4 Silk Screen 4 to 12 gsm

The present invention uses offset printing.
,CLAIMS:1. A process of printing on a packaging with UV sensitive ink comprising the sequential steps of:
(i) printing a graphics and elements on the packaging by processes selected from Offset, Gravure, Flexography, Screen and Letter-press such that the deposition of conventional ink is between 0.2 to 12 GSM;
(ii) printing selected areas on said packaging through offset printing processes with the UV sensitive ink comprising additives/ pigments such that the deposition of conventional ink is between 0.2 to 12 GSM;
wherein said UV sensitive ink comprises 20 to 25% by weight UV monomer (low molecular weight), 40 to 45% by weight UV Oligomers (high molecular weight), 20 to 25% by weight of pigments, 5 to 10% by weight of additives.
2. The process of printing on a packaging with UV sensitive ink as claimed in claim 1 wherein said packaging material is selected from Paperboard, Plastic, Laminates, Glass, Metals, leather, Wood or any other material known to be used in consumer goods industry.
3. The process of printing on a packaging with UV sensitive ink as claimed in claim 1, wherein said UV monomer is selected from process coloured UV inks used for printing are isobornyl acrylates (monofunctional), triproylene glycol diacrylates (difunctional monomer), trimethylol propane triacrylate (trifunctional monomer) and the like.
4. The process of printing on a packaging with UV sensitive ink as claimed in claim 1, wherein said UV Oligomers is selected from process coloured UV inks used for printing are epoxy acrylates e.g. bisphenol A diglycidyl ether diacrylate, urethane acrylates.
5. The process of printing on a packaging with UV sensitive ink as claimed in claim 1, wherein said Pigments is selected from Fluorescent pigments such as cyan U1670, magenta U1688, yellow U1647, black U1669 and the like, present in the range of about 15 to 20wt% .
6. The process of printing on a packaging with UV sensitive ink as claimed in claim 1, wherein said Additives are photo initiators of 1.5 wt%.
7. A packaging material employing the process of any preceding claim, is visible when exposed under UV region.
8. A packaging material employing the process of any preceding claim is made to visualize single and/or multiple colors when exposed under UV region.