UV Inkjet Printing on Food Packaging: State-of-Art and Outlook

Transcription

1 UV Inkjet Printing on Food Packaging: State-of-Art and Outlook uv.eb WEST 2015 Crowne Plaza Hotel & Marina Redondo Beach, CA Roel De Mondt, PhD Agfa-Gevaert N.V., Belgium

2 Analog or digital? Why printing?! decoration, information, marketing, identification Analog printing: Examples: gravure printing, pad printing, offset printing, flexography, screen printing, Master to be made for each print colour Fixed setup cost divided by number of prints! preferably large print runs Digital printing Laser/toner/EP vs. inkjet 2

3 ABC of inkjet printing Digital, non-contact printing method no master (plate or sleeve) direct from image file to substrate Ink properties for jetting process N o 1 = low viscosity, Ink properties for application surface tension for image quality UV curable for non-absorbing substrates 3

4 Low migration inks Packaging printing Indirect printing (printing on the non-contact side) Primary food packaging (food and beverages) Direct on food container Lids and closures Pouches Foils (wrap, flexible, laminates, ) Labels Secondary food packaging Pharmaceutical packaging Direct print on medical bag, syringes, etc Foils (mostly alu based blisters) Secondary packaging 4

5 Direct printing Label printing vs. Direct Printing Label printing = 3 steps Step 1 : printing of product information on label (roll) Step 2 : mount printed label roll on applicator Step 3 : label application Direct printing = 1 step Direct print of product information on the packaging Advantages: no label stock, no master, variable run length, fast change of product information ( on the fly ), variable data, Direct print on food packaging Direct print with UV LM inks on the primary food packaging e.g. food container! highest demand to LM inkjet inks for jetting, physical properties and low migration 5

6 Value proposition State-of-the-Art label order design Delay Drink Manufacturer logistics Label printer stock Cost glue fill Bottle manufacturer ship stock Drink Manufacturer Innovation fill ship inkjet Bottle manufacturer stock 10 March 2015 Value propositionr De=Mondt JIT + Cost effective Solution 6

7 What is a Low Migration ink? There is no such thing as LM inks An ink can have intrinsically beneficial properties for LM An ink is expected to be able to yield a safe food packaging if the necessary precautions of e.g. curing (dose, UV type, ) have been taken. Combination and control of all parts of the print solution Food packaging printing needs to be a controlled process Substrate (barrier quality) LM UV-curable inkjet ink Printing and process conditions Environmental conditions Food safe packaging 7

8 Low migration system concept Amount of ink + curing only variable info or full label information Toughest applications barrier quality Food type Substrate type water! alcoholic beverage! oil based 8

9 Sustainability via digital printing for food packaging Communication VOC Substrate scrap Transportation Accessible health information Warehousing QR Food safe print Environment Short run Lead times Sustainable Digital printing Recycling LED 9

10 Food safety ENDANGER HEALTH CHANGE SMELL TASTE 10

11 Primary Food Pack: Overview of legislations Ink specifications: Swiss Ordinance , German Bedarfsgegenstand? EuPIA Guideline on Printing Inks applied to the non-food contact surface of food packaging materials and articles EuPIA Exclusion List for Printing Inks and Related Products EuPIA Suitability List of Photo-Initiators for Low Migration UV Printing Inks and Varnishes Food packaging regulations where inks may be involved: General Framework Regulation 1935/2004/EC Plastics regulation 10/2011/EC GMP 2023/2006/EC Company specific claims Company List of Restricted substances (e.g. soluble azo dyes, heavy metals such as lead, hexavalent chromium, mercury and cadmium). ITX, benzophenone or 4-methylbenzophenone Nestle list Common ground in legislations: 10 µg / 6 dm² (6 dm² is the typical packaging area for 1 kg of food)!10 µg/ 1 kg = 10 ppb: rule-of-thumb for the allowable specific migration limit for the different ink compounds. If sufficient toxicological data available, this limit can be higher.! Define LOW MIGRATION: Swiss Ordinance? Low odor? No migration? 11

12 Let s formulate! Which pigments do you choose? What monomers will you disperse the pigments in? What functional needs does your ink have: adhesion, smell, chemical resistance, indoor/outdoor, indirect food contact, Choose the right monomers / oligomers! At what wavelengths should the inks be cured and how much UV dose is available in how many steps (lamps, speeds, window)?! Which photoinitiators will you need? What is the surface tension you are aiming at: fire frequency, nozzle plate coating? Which functioning combinations can be stabilized for 12 to 18 months? Do you have freedom-to-operate for the chosen combination? 12

13 UV ink and ink compounds monomers photo-initiator pigment additives 13

14 UV ink photoinitiation Theory: match output UV - absorption of photoinitiator UV-emission UV-absorption PI PI* Output + Reality: Pigment absorption! 14

15 LM ink technology 15

16 Not free to formulate for LM inks 16

17 Migration testing Single sided extraction - dependent on the application different simulants can be used at different temperatures e.g. water, water + acid, water/ethanol mixtures, ethanol, - identification and/or quantification of extracted compounds 17

18 Migration testing Single sided extraction - dependent on the application different simulants can be used at different temperatures e.g. water, water + acid, water/ethanol mixtures, ethanol, - identification and/or quantification of extracted compounds 18

19 Migration of molecules? ~ viscosity ink substrate FOOD 19

20 How to go for Low Migration in inkjet then? Highly reactive monomers Low tox or diffusion hindered photoinitiator 20

21 Details of formulations Low viscous but highly reactive monomers monomer comprising: at least one acrylate group at least one other ethylenically unsaturated polymerizable group preferably selected from the group consisting of: a vinylether group, an allylether group and an allylester group 21

22 Details of formulations Diffusion-hindered photo-initiators / co-initiators Polymeric PI and/or CO-INI multi-functional! higher probability of reaction higher MW! low migration speed dendritic polymeric architecture! low viscosity 22

23 Details of formulations Diffusion-hindered photo-initiators / co-initiators Polymerizable PI or CO-INI becomes part of the polymeric network! bonded PI or bonded CO-INI cannot migrate low MW! very low viscosity, but high migration speed examples : 23

24 Low Migration UV-curable inkjet inks how? Purity analytical efforts (supplier or ink producer) free of solvents, heavy metals, specific note on pigments! manageable Nature of compounds: e.g. photo-initiators selection of low toxicity compounds = possible options : polymeric and/or polymerizable Reaction products non intentionally added compounds of another level than impurities tricky compounds because unknown when formulating Polymerization degree Compliant with legislation and guidelines compliant with European Framework Regulation 1935/2004/EC compliant with EuPIA, all ink compounds on positive list Swiss Ordinance Swiss Ordinance all materials are TSCA (USA) and REACH compliant other 24

25 Examples KHS Bottling lines Direct Print Polytype Print equipm. food containers DigiCup printer Sacmi food pack. equipm. Colora cap 25

26 Summary Inkjet printing on packaging = answer to packaging trends UV LM inkjet ink formualtion " low viscosity for jetting Thereby requires full conceptual development of LM ink concept Monomers and photo-initiators need to be LM ink specific designed for combination of low viscosity and high curing degree Dedicated LM ink technology can result in low migration levels Highly reactive monomer is key driver to full curing Diffusion-hindered PI system key to curing speed (UV LED curing) and low migration of PI s 26

27 Thanks for listening 27