design4food, optimized inking for food packaging

Design4Food Optimized inking for food packaging

Fons Put 30 September 2015

[email protected] www.vigc.be

Typical packaging printing proces

§  Process colors �  Illustrations

§  Spot colors �  Branding

§  Laquer/varnish �  Finishing & protection

9/29/15 Optimized inking for food packaging 2

Critical side effects (1)

§  Set-off (scope) �  Contact between printed side and reverse side in a

printed pile or roll �  This contact can cause a transfer of ink & laquer to

the reverse (unprinted) side of the substrate


Critical side effects (2)

§  Migration (out-of-scope) �  Transfer of chemicals to the food-contact side �  Example: Rüdiger Helling (Lua Dresden)


Migration of chemicals from printing inks into packaged food – Results of a German market and production survey

Rüdiger Helling3, Koni Grob4, Werner Altkofer1, Diane Fügel1, Lydia Richter2, Thomas J. Simat2 1 CVUA Stuttgart/D, 2 TU Dresden/D, 3 LUA Dresden/D, 4 KL Zürich/CH

Introduction

Almost any food packaging is printed intensely and colorful, but only little is known about the migration potential of printing ink components into food. For this reason a research project was initiated and financed by German Federal Ministry of Food, Agriculture and Consumer Protection (BMELV) in order to gain reliable survey data to further evaluate the need for a legal measure for printing inks used for food contact materials. The presented study was conducted from Dec 2009 to May 2011 and was the first systematic approach to assess the migration potential of printing inks for a wide range of daily used packaged food products covering both samples from the market and the situation at the manufacturer`s stage. The aim of study was finding causal interrelation between the applied ink components/technique, the composition of the packaging material and the determined concentration in the food by taking into account the wide range of various packaging materials and the chemical/physical properties of the food as well.

References:

Dupáková, Z., Dobiás, J., Votavová, L., Klaudisová, K., Voldrich, M.: Occurence of extractable ink residuals in packaging materials used in the Czech Republic. Food Add. Contam. 27, 97 (2010)

Richter, T., Gude, T., Simat, T.: Migration of novel offset printing inks from cardboard packaging into food. Food Add. Contam. 26, 1574 (2009)

Sanches-Silva, A., Andre, C., Castanheira, I., Cruz, J.M., Pastorelli, S., Simoneau, C., Paseiro-Losada, P.: Study of the migration of photoinitiators used in printed food-packaging materials into food simulants. Journal of Agricultural and Food Chemistry 57, 9516 (2009)

This study was financed by the Federal Ministry of Food, Agriculture and Consumer Protection (BMELV), Germany managed by the Federal Office for Agriculture and Food (BLE), Germany, project number 09HS007.

Figure 2: Colored printed labels as an underestimated contamination source GC-MS mass trace [SIM modus] of quantified ink-compounds

.

Result and Outcome

Within the survey, 65 substances with a potential for migration were identified in the printing layers of food contact materials, 41 of which were detected and quantified in foods. Of these, 20 were without toxicological evaluation.

In general, UV-cured inks may release photoinitiators and their degradation products as well as low molecular weight acrylates.

Plasticizers were found to migrate via set-off and gas phase transfer from flexographic printing (e.g. packaged sweets)

In the case of cold- and heatset off-set printing as mainly applied for cardboard solvents are the most critical constituent.

Some cardboard boxes printed with mineral-oil-based inks were still encountered, with high migration into the packaged food.

Low-migration printing inks are available for most applications, but are not always used in critical cases.

Intensively printed, self-sticking labels are an up to now underestimated contamination pathway. Migration of photoinitiators from such labels into food easily reached the mg/kg level.

Transparency within the supply chain is essential for the production of compliant and safe food packaging material Consideration of NIAS (“Non Intentionally Added Substances”) as a

contamination source caused by e.g. raw material impurities or reaction side products are a future task

Based on the results of the project German Ministry (BMELV) concluded to introduce specific requirements for printing inks into national legislation. A first and second draft were already distributed for annotation.

For further details and results please refer to the published report (http://www.ble.de).

Verification of ink composition

Analysis at different storage times

Experimental

Analysis at the end of shelf life

Food / Foodsimulant

Specific compound analysis

by GC-TOF/MS GC-MS LC-MS-MS LC-GC

Applied techniques: - microtome cutting / IR - chemical testing - GC-TOF/MS - GC/MS - LC/MS/MS; LC-DAD/FD

Package Parameters: - Layer design - Printing technique - Kind of ink - Ink characterization - Specific printing ink components

If calculated 100 % migration is >10 µg/kg food

32 food samples from retail (like dairy products, breakfast cereals,

sweets, snacks, cheese, meat and sausages)

25 samples taken from the manufacturer´s site

(unpacked food, (un)printed packaging material, printing ink (composition requested)

sausage packed in multi-layer plastic casing

Microtome cutting of the complex layer

Applied technique: UV flexo printing

outer face

printing ink polyamide bonding polymer (PUR) polyethylene red coloured bonding polymer (PUR) polyamide

food contact side

Figure 1: Permeation of photoinitiators through the multi-layer casing (LC-MS/MS) I. Quantified photoinitiators - casing II. Quantified photoinitiators - sausage

Practical Examples

Permeation process

Irgacure 127

2-Benzyl-2-(dimethylamino)- 4-morpholino-butyrophenone

Esacure 1001M

Phenyl-bis-(2,4,6-trimethyl- benzoyl)-phosphinoxide Diester of carboxymethoxybenzo- phenone and polytetramethylene- glycol

Irgacure 127

2-Benzyl-2-(dimethylamino) -4-morpholino-butyrophenon

155 ppb Irgacure 127

10 ppb 2-Benzyl-2-(dimethylamino)-4-morpholino-butyrophenone

I. II.

cookies (chocolate-covered)

self adhesive sticker (UV-printed paper)

31 µm polypropylene mono layer

2-Ethylhexyl-4-(dimethylamino)benzoate

Benzophenone

2,2-Dimethoxy-2-phenylacetophenone

4-Benzoylbiphenyl

1-Hydroxycyclohexyl-phenylketone

Methyl-2-benzoylbenzoate

Benzophenone 1500 ppb

sticker cookies

48 ppb in food (Signal not shown)



Regulations concerning set-off

§  Best practices: Regulation EC 2023/2006 �  ‘Good manufacturing practice for materials and articles

intended to come in contact with food’ �  There shall be no migration from printed side to food-

contact side! �  Applies to the total packaging chain:

�  Substrate suppliers �  Ink manufacturers �  Adhesive manufactures �  printers/convertors �  Packers/fillers �  Dixtributors �  Retailers


Set-off solutions in the market

§  Dry contact surfaces �  Balanced ink drying



§  Prolong the time before contact �  Press design



§  Accelerate drying through hot air, infrared light, …



§  Reduction of the contact surface �  use of powder



§  Artificial ink drying �  UV-inks, Low Energy UV


What can be done before printing?

§  Design: critical zones for set-off �  Heavy ink coverage


Design for Food

§  Concept �  Lowering ink consumption without affecting color �  Applicable in the design stage or at the plate making

proces �  ICC-profiles to calculate (design) or recalculate

(plate making) separations §  Advantages

�  Lower risk for set-off �  Less material (ink) means less migration (linear

relationship)


ICC-profiles for ink reduction

§  Maximum ink limit �  A threshold for the total ink coverage

�  ISOcoated_v2_eci: 325% max. Inkt limit

� Coated_Fogra39L_VIGC_220: 220% limit


ICC-profiles for ink reduction

§  Use of black in color separation �  Colors can be composed with different amounts of

black and color inks. � Separation with medium black

� Separation with heavy black


Print trials

§  Evaluation of the printed color gamut �  Start: ISO 12647-2 �  Substrate correction �  Laquer/Varnish effects


Print trials

§  Evaluation of the printed color gamut �  Example: low migration inks on cardboard


C M Y K A B C A B C

zwart (enkel)

2.4 3.6 6.0 A 1.1 2.4 3.6 6.0

0.7 2.4 3.6 6.0

A

2.4 3.6 6.0 A 0.9 2.4 3.6 6.0 A

A

0 0 0 20 0.3 2.4 3.6 6.0 A 0.5 2.4 3.6 6.0 A

1.4 1.5 2.4 4.0 A

CMY halftonen

RGB halftonen

0 0 0 10 0.3

0 0 0 40 1.1

0 0 0 60 1.8

70 70 0 0 1.2 1.5 2.4 4.0 A

4.0 C 1.1 1.5 2.4 4.0 A

3.5 1.5 2.4 4.0 C 0.8 1.5 2.4 4.0 A

4.0

4.0 A

4.0 A

0 0 40 0 0.7 1.5

40 0 0 0 2.9 1.5 2.4 4.0

0 40 0 0 1.3 1.5 2.4

0 0.8

C 0.4 1.5 2.4 4.0 A

A 0.5 1.5 2.4 4.0 A

1.5 2.4 4.0 C 1.0 1.5 2.4

40 0 40 0 2.7 1.5 2.4 4.0 C 0.6

70 0 70 0 3.0 1.5 2.4

0.8 1.5 2.4 4.0 A

0 0

0 0

70

40 40 0 0 0.8 1.5 2.4 4.0 A

1.5 2.4 4.0 A

A

1.5 2.4 4.0 B 0.4

1.5 2.4 4.0 A 0.4 1.5 2.4 4.0 A

0 80 2.6 2.4

2.4 4.0 A 0.4 1.5

0 70

3.6 6.0 B 0.9 2.4 3.6 6.0

2.4 4.0 A

0 40 40 0 1.9 1.5 2.4 4.0 B 0.6 1.5 2.4

0 0 0 2.5

0 70 0 0 1.9

70

70 0

1.5 2.4 4.0 A

2.4 3.6 6.0 A

1.6 1.5 2.4 4.0

score

A

C

A

C

B

A

score

A

A

A

A

A

B

2.4 3.6

Secundaire kleuren (samendruk 2 inkten)

variatie toleranties ΔE2000

0.8 1.5 2.4 4.0

0.6 1.5 2.4 4.0

0.3 1.5 2.4 4.0

0.9 1.5 2.4 4.0

100 100 0 0 1.2 1.5 2.4 4.0

0 0 0 100

2.4 4.0

0.8 1.5 2.4

100 0 100 0 1.9 1.5 2.4 4.0

1.8zwart (volvlak)

0 100 100 0 2.5 1.5

1.5 2.4100 0 0

6.0 A

4.0

2.4 3.6 6.0 A0.4

Primaire kleuren (inktkleuren)

digital deviatie toleranties ΔE2000

4.0

1.0 1.5 2.4

4.00 0 100 0

100 0 0 0 1.0 1.5 2.4 4.0

0 2.8

Print trials

§  Evaluation of maximum ink limit �  325% - 260% - 220%


Print trials

§  Evaluation of maximum ink limit �  Does a higher ink coverage produce a darker black?


325% 260% 220%

Print trials

§  Evaluation of maximum ink limit �  Does a higher ink coverage produces more set-off?


!

Print trials

§  Evaluation of maximum ink limit


400% ECI% 320%

300% 260% 220%

Print trials

§  Evaluation of black in separation �  Identical colors

�  without black ink, medium and maximum black


Print trials

§  Evaluation of black in separation �  Which separation type produces accurate colors? �  Example with low migration inks


No black ink ( CMY only) Maximum use of black ink Medium use of black ink

Print trials

§  Evaluation of black in separation �  Does the heavy use of black ink promotes stability in

printing?


Print trials

§  Evaluation of real-life design


Print trials

§  Evaluation of real-life design �  Mathematical method

� Sampling of dominant design colors � Calculating 2 separations

�  Original 325%, medium black �  220%, heavy black

� Color measurement & difference (dE2000)


Print trials

§  Evaluation of real-life design �  Mathematical method


C M Y K L* a* b* ΔCIE2000 ΔL ΔC ΔH C M Y K ΔCIE2000 ΔL ΔC ΔH ΔCIE2000

1 10 70 52 2 56.0 41.8 19.8 3 2.5 -1.0 -1.5 1 68 48 10 3 3.0 -0.5 0.8 1

2 44 62 67 64 27.5 8.1 9.3 3 2.5 0.0 -2.2 23 51 57 74 3 3.0 0.7 1.6 1

3 35 85 64 57 26.1 23.1 8.6 2 2.6 -1.7 -0.8 13 78 51 68 2 2.8 -2.0 0.4 0

4 63 68 56 76 18.8 3.8 -0.1 3 3.5 -0.7 -1.2 37 48 35 88 3 3.2 -0.2 -1.4 1

5 59 77 64 86 14.6 5.2 2.0 3 3.5 0.2 -1.2 29 55 40 94 2 3.4 0.4 0.8 0

6 60 62 57 67 23.5 3.3 1.1 2 2.5 -0.4 -1.1 35 44 38 82 3 3.1 0.0 0.8 1

7 82 72 62 91 11.8 -0.6 -1.0 3 3.6 -0.8 -1.4 47 38 33 100 4 3.5 0.6 -3.0 2

8 69 80 61 89 12.6 3.5 0.0 3 4.0 0.0 -1.1 37 51 33 97 3 3.9 0.4 -1.9 1

9 35 80 63 45 31.3 24.9 10.1 4 3.9 -1.9 -1.9 12 74 51 60 3 3.6 -2.0 0.2 1

10 46 70 63 70 22.9 9.6 5.4 3 3.6 -0.3 -2.2 24 59 49 80 3 3.7 -0.3 1.0 1

11 53 60 60 63 27.1 4.8 4.2 1 1.2 0.4 -0.5 31 46 45 76 2 1.9 0.6 0.2 1

12 50 56 51 55 31.8 5.8 2.4 1 1.3 0.0 -0.5 31 45 38 68 1 1.1 0.0 0.1 1

separatie 1/2originele separatie: druk versus target separatie VIGC 220: druk versus targetKleurnr

Print trials

§  Evaluation of real-life design �  Visual method

� Comparison in a light cabinet �  5 basis and 5 optimized samples


Conclusions

§  Food packaging printing is a specialised printing proces �  Choise of substrate (odour, recycling) �  Choise of ink (low migration) �  Food-safe printing (set-off) �  Complexity of ink-drying

§  Protection against set-off by using an optimized color separation (ICC) �  Choise of maximum ink limit: 220% is possible without

affecting colors �  Choise of black generation in separation: maximum

black further lowers the ink consumption and increases color accuracy and stability


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design4food, optimized inking for food packaging

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