1. Diversity of Inks - Structure and Requirements

2. Components of Printing Inks
Colorants
Optical properties and fastness
Binders (polymers, resins and liquid components)
Printability and drying
Additives
Controlling specific properties
Despite the diversity of systems these are composed basically similar.
Each system contains COLORANTS - BINDERS - ADDITIVES and liquid components.
COLORANTS are mainly used for the optical properties. Here also the requirements of the end application must be considered on the pigments with respect to the necessary resistances.
BINDERS are solid polymeric components, which are often converted in the first step with liquid components in liquid form in order to achieve easy handling. The combination of binders and liquid components is essential in many cases for good printability and appropriate drying of printing inks.
The ADDITIVES in printing inks are like spices, pepper and salt for cooking. They are usually added in small amounts and are used to achieve and control specific properties.

3. Colorants: Mainly Pigments
Organic pigments
Synthetic high-tech chemicals
Inorganic pigments
Carbon black (high-purity specialty carbon) and titanium dioxide
Effect pigments
Aluminum, bronze, pearlescent pigments
In most inks organic and or inorganic pigments are used as colorants (soluble dyes only for very special applications). Organic pigments are synthetic high-tech chemicals. Inorganic pigments are e.g. highly purified special carbon, often simply referred to as carbon black, and titanium dioxide.
In addition to these colorants, there is also effect pigments such as aluminum, brass and pearlescent pigments.
The amount of ink applied to various substrates is low. Today dried layers of ink have an application weight of only about g/m². The amount of ink application has been reduced in the recent years and this trend is not yet completed. The reduction of amount of ink allows the improvement of the print quality and a more detailed reproduction of subjects. The color intensity of the printed images has however not been reduced. Therefore, it is now essential that inks have very high pigment concentrations. We speak of pigment concentrations up to 30 %. An exception to this is the screen printing process, because the amount of ink application is higher in this printing process.

4. Water-based Inks Binder Composition Drying process Mostly acrylates
15 – 25 % pigments 10 – 25 % polymers/resins 8 – 12 % additives 35 – 65 % water
Physically by penetration into the substrate and evaporation
The next slides show the basic composition and the main fields of application of water-based inks.
The inks contain mostly up to 15 – 25 % of pigments and approximately the same amount of binder. In water-based inks mainly acrylates are used as binder. Water-based inks generally contain 8 – 12 % of additives. This is significantly higher than in many other ink systems. In water based inks the use of wetting agents (surfactants) for stabilization is essential with the result that here, too, a significant concentration of defoamer is required. The rest of up to 65 % consists of water.

5. Water-based Inks Printing process Substrates Printed objects
Flexography and gravure printing
Paper, cardboard, tissue, aluminum foil, plastic films for special applications
Corrugated board, paper, wallpaper, furniture decoration, newspapers, beverage cartons, folding cartons, napkins, packaging material
You will be surprised at how many fields of application water-based inks are used nowadays. A few years ago only absorbent substrates were printed with water-based inks. But today more and more so-called non-absorbent substrates such as aluminum and plastic films are printed with these systems.
The most popular products are corrugated board, tissue for example, Napkins, kitchen towels and toilet paper as well as wrapping paper and bakery bags even beverage cartons and flexible packaging. A large segment of the market for water-based ink systems is the manufacturing of wood imitations on paper, films and the production of laminate flooring. Even newspapers are now printed with water-based inks.
A deeper insight on the use of water-based inks, you get in the lecture 12 "The versatility of water-based printing inks and overprint varnishes".

6. Solvent-based Inks Binder Composition Drying process
NC, PU, PVB, PA, PVC and acrylates
12 – 18 % pigments 12 – 18 % polymers/resins 2 – 5 % additives 35 – 65 % solvents
Physically by evaporation
Due to the huge number of substrates and the diversity of applications in packaging the binder system of solvent-based inks has to be carefully adjusted to the needs of the application. The main types of polymers used as a binder are NC = nitrocellulose, PU = polyurethane, PVB = polyvinylbutyral, PA = polyamide, PVC = polyvinyl chloride. In Order to customize the inks to the substrates and the end-use application, very often different polymers are combined.
The choice of solvents depends on the binder composition and the requirements of the printing process to the drying behavior of the inks (gravure printing – fast drying speed, flexography – medium drying speed, screen printing – slow drying speed).
During the drying process the solvent evaporates and leaves an odorless ink film.

7. Solvent-based Inks Printing process Substrates Printed objects
Flexography, gravure and screen printing
Aluminum foil, plastic films, laminated films also paper and cardboard
Packages of all kinds (frozen, sterilization, beverage packaging, labels)
In many cases the edition size and the characteristics of the substrate determines the selection of the printing process (large jobs, stable substrate = gravure; medium and small jobs, elastic substrates = flexographic printing on CI presses).
The properties of solvent-based inks can be adjusted to nearly all substrates and end-use applications. For reverse printing and subsequent lamination ink and adhesive system has to be coordinated. Therefore, there is a huge diversity of ink series with special binder/additive combinations.
In the process of designing packaging inks the further conversion of printed substrates to packaging material and the demands of the processing of finished and filled packages has to be considered.

8. Publication Gravure Inks
Binder Composition Drying
Rosin modified resins (resinates), hydrocarbon resins, asphalt, solvent: toluene
12 – 15 % pigment 20 – 30 % polymers/resins 2 – 5 % additives 45 – 60 % toluene (standardized)
Physically by penetration and evaporation
Toluene based inks for publication gravure contain binders based on resinates, which are derived from natural rosin, and some times on hydrocarbon resins or asphalt. For drying, the solvent toluene is evaporated from the ink film after every printing unit. After this the toluene becomes absorbed to keep the air clean and for later recycling.

9. Publication Gravure Inks
Application Substrate Printed objects
Publication gravure printing
Paper
Magazines, catalogues, advertisement leaflets in the premium market
The classical application for publication gravure are graphic printings which are used in the premium market; catalogues, magazines, and advisement leaflets. Due to the changes in consumer behavior the need for such printed objects is declining. Therefor the relevance of this printing technology is shrinking since years.

10. Offset Coldset Inks Binder Composition Drying
Rosin modified resins, bitumen, asphalt, solvent: mineral oil, vegetable oil, modified vegetable oil
8 – 20 % pigment 25 – 35 % polymers/resins 2 – 5 % additives 40 – 60 % oils
Physically by penetration
The binders of offset coldset inks are based on rosin modified resins and for the black inks on bitumen and asphalt. The liquid components are mineral oils as well as vegetable oils in pure and modified version. As web offset coldset presses are not equipped with a drying equipment, these inks are only drying by penetration.

11. Offset Coldset Inks Application Substrates Printed objects
Web offset coldset
Newsprint
Newspapers, advertisement leaflets
Due to this this printing application is only suitable for the use of absorbent newsprint. Newspapers are the classical printed objects for this printing process. Since some years it is common the use coldset presses during daytime to print advertisement leaflets. As the use of newspapers is declining in edition and volume also the consumption of coldset inks is going down.

12. Offset Heatset Inks Binder Composition Drying
Rosin modified resins, hydrocarbon resins, solvent: mineral oil
8 – 15 % pigment 25 – 40 % polymers/resins 2 – 8 % additives 30 – 45 % mineral oil
Physically by evaporation
Web offset heatset inks are containing as binders rosin modified resins and hydrocarbon resins. As solvent mineral oils are used which boiling range is chosen according to the needs of the evaporation in the heatset drying oven. To clean the air and to obtain energy the mineral oil vapors are burned after the drying process.

13. Offset Heatset Inks Application Substrates Printed objects
Web offset heatset
Paper
Magazines, catalogues, advertisement leaflets
Typical prints made with web offset heatset are magazines, catalogues and advertisement leaflets. Web offset heatset is the printing application which increased the market share at the highest rate in the last decades.

14. Conventional Sheetfed Inks
Binder Composition Drying
Rosin modified resins, alkyd resins, fatty acid esters, vegetable oils* (linseed oil, soybean oil), mineral oil*
10 – 30 % pigment 25 – 35 % polymers/resins 5 – 10 % additives 30 – 40 % liquid components
Physically (penetration) and chemically (oxidative drying)*
The binder – also called varnish - consists of several resins and oils, normally in the ratio 50:50. There are mineral oil free binders on the base of renewable resources as well as binders with about 25 % mineral oil. Mineral oil creates a low water uptake and therefore gives advantages for the ink-water-balance. The main function of the binder is to immobilize the pigment on the paper. Special properties of the ink as gloss, rub resistance or drying speed are adjusted by the choice of varnishes and additives. Resistances against light or solvent based varnishes are determined by the choice of the pigment.
The raw materials marked with an asterisk are not suitable for the production of sheetfed inks for food packages. Such inks have to be optimized in terms of smell and migration and should not dry by oxidation (as during this decomposition products are originated which may cause small). Additionally all raw materials for this specific use have to comply with the migration limits.

15. Conventional Sheetfed Inks
Application Substrates Printed Objects
Sheetfed Offset
Paper and board
Magazines, books, calendars, poster, advertisement leaflets, flyers, packaging
The diversity of sheetfed printing can be seen in different aspects. There is a large variety of printing press configurations. In use are printing formats from DIN A 3 to 150 x 200 cm, printing presses with 1-14 printing units, for straight printing and perfecting which may be additionally equipped with one ore more coating units on variable positions in the press. Further there are nearly no limitations for the substrates. Sheet shaped materials in all formats, weights and paper grades may be used. A further argument for the diversity of sheetfed printing is the possibility to use any spot colors or effect inks and to do various finishing steps. Due to this sheetfed printing is used to produce a big variety of printed matter.

16. Binder Composition Drying
Radiation Curing Inks
Binder Composition Drying
Acrylates, oligomers, prepolymers
10 – 30 % pigment
40 – 80 % polymers/resin
10 – 20 % additives (incl. photo initiators, PI)
Chemically, photo chemically (UV, LED, EB) induced crosslinking
Energy curing printing inks and lacquers are based on acrylates, oligomers and prepolymers which - induced by photo initiators (UV) - radically polymerize during the printing process. So, drying of energy curing systems is photochemically induced. After proper processing, these inks are completely cross-linked and ready for finishing.

17. Radiation Curing Inks Application Substrates Printed objects
Flexo printing, gravure, offset, dry offset, various screen printing processes
Paper, board, aluminum, plastic foils, plastics
Packaging, labels, finishing, plastic bottles, container, tubes, … (UV-varnished covers, effect varnishing)
Radiation curing inks systems are used in the printing technologies flexography, gravure, offset, dry offset, and various screen printing processes. Plastic, plastic foils, aluminum and also paper and board are suitable substrates.
Examples for printed objects are packaging, labels, plastic bottles, plastic container, yoghurt lids, hollowware, tubes, varnished covers, effect varnishing.

18. Printing Inks – Overview
Ink system
Pigment [%]
Polymer/ resin [%]
Additive [%]
Solvent/
liquid compound [%]
Water based
15 – 25
10 – 25
8 – 12
up to 65
Solvent based
12 – 18
2 – 5
Toluene based
12 – 15
20 – 30
up to 60
Screen inks
8 – 20
25 – 40
2 – 8
Sheetfed (standard)
10 – 30
25 – 35
5 – 10
up to 40
Energy curing
40 – 80
10 – 20 -
This table should give you a rough overview of the composition of different printing ink systems in a direct comparison.
It can be said that most printing inks are made with about 10 to 20% of a colourant. Another 20 – 30% are solid binders, meaning polymers or resins. And up to 70% of an ink system are liquid components.
Energy curing systems are in a sense special with regard to composition: in this case all more or less liquid compounds can be seen as part of the binder, i.e. as solid polymers, as they are one of the constituents of the cured and thus polymerized ink film. This is the reason why in the table the quantity of polymers / resins for energy curing systems is given with up to 80%. A typical liquid compound, on the other hand, is not part of an energy curing ink formulation.

19. Packaging printing Label printing Digital printing Graphic prints
Market Trends
Packaging printing Label printing Digital printing Graphic prints
The development of different market segments in printing industry is more or less constant for several years now:
The whole range of packaging printing, especially food packaging printing, is a growing market. Directly linked with packaging, label printing is growing as well.
In both areas the use of energy curing ink systems is getting more and more important. When looking at types of ink systems this means that the quantity of energy curing inks is growing strongly. Today about 2% of the whole printing ink market are covered by energy curing inks and overprint varnishes.
Another growing market is digital printing.
The importance of graphic prints in contrast is still decreasing.

20. Raw Material Selection - Criteria
Technical requirements
Printing and drying mechanism
Requirements related to the printed article, processing and final application
Regulatory requirements
Availability and price
The successful usage, respectively the processing of a printing ink in products, which afterwards will be marketed, is strongly dependent on the selection of suitable printing ink raw materials.
The raw material selection is based on three success pillars, represented on this sheet.
A close collaboration between the final customer, the printer/converter and the printing ink manufacturer is needed in order to achieve at the end the desired functionality of the ink. The printer/converter has to be informed by his customer about the requirements of the product (e.g. packaging design, packaging specifications). Depending on that, he will be able to forward to the printing ink manufacturer the requirements on the printing ink (e.g. chosen printing process, drying, etc.). The printing ink manufacturer will recommend a suitable ink, which fulfils the set specifications and will issue in the value chain recommendations describing the use. Subsequently, the recommended ink will contain exactly the raw materials that can ensure the fulfilment of all the earlier mentioned requirements.
Principally, all raw materials used in printing inks must comply with regulatory requirements. It has to be differentiated between legal requirements (predefined by law), the self-commitment of the printing ink industry and the additional requirements of customers, which are strongly dependent on the area of use of the printing ink.
These requirements are going to be treated into more detail on the next slides.
The selection of suitable raw materials depends certainly also on the availability. A close tracking of the raw material market situation, of innovations as well as of the availability of resources is needed in order to ensure a constantly available top raw material portfolio.

21. Regulatory Requirements
Legal requirements
Chemical legislation, REACH, CLP, labelling and classification
Worker safety, environmental safety
Voluntary self commitment
EuPIA-Exclusion policy – no use of toxic and CMR substances
Raw material exchange after changes in classification
As already mentioned previously, the printing inks and subsequently also their ingredients (raw materials) must comply with legal requirements. We can take the example of the EU: The risks originating form chemicals are displayed on labels and safety data sheets by the use of standardized phrases and pictograms, having as a background the requirements formulated in the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures. Inks and lacquers, which are subject to classification, have to be delivered accompanied by a safety label and safety data sheet. The EU is implementing the requirements of the Globally Harmonized System for classification and labeling of chemical (GHS) with the help of the CLP-regulation. THE GHS is a system of the United Nations, having as a scope the identification of dangerous chemicals and the information of the user on the respective hazards.
The term “REACh” is derived from the title of the Regulation: Regulation concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals, (Regulation (EC) No 1907/2006). It is implemented since According to REACh, each producer or importer of chemicals has to register each individual substance under his name, based on a large amount of data, which has to be provided to the European agency ECHA. The slogan “no data, no market” is very well describing the situation. Therefore, printing ink manufactures have to ensure that they use only substances in their products, which cover all requirements.
Furthermore, raw materials have to comply during handling and processing with worker safety and environmental protection requirements as well.
Additionally to the legal requirements, the EuPIA (European Printing ink Association) members decided to undergo a self-commitment. On a voluntary basis member companies refrain from using certain raw materials in the formulations of their printing inks. The criteria are set in the “Exclusion Policy for Printing Inks and related Products”. Raw materials classified as carcinogenic, mutagenic, reprotoxic and toxic are not used.
This results in a commitment to exchange raw materials where a nonconformity with the EuPIA Exclusion Policy would be the consequence of a reclassification.

22. Regulatory Requirements
Printing inks for food packaging
Regulations
EU-Framework Regulation (EC) No. 1935/2004 (general requirements)
GMP Regulation (EC) No. 2023/2006 – good manufacturing practice
Swiss Ordinance on materials and articles; packaging inks
EuPIA-Guideline and specific customer requirements
Printers and converters have to operate our days in a very complex environment in order to be able to deliver safe products. End user and brand owner are expecting safe packaging. Food contaminations or the damage of health originating from packaging material has to be excluded.
The basic principles for regulations in the food packaging area are based on existing regional regulations.
The EU-Framework Regulation (EU) No 1935/2004 is essential since it sets the main requirement: 1. “…under their normal or foreseeable conditions of use, they do not transfer their constituents to foodstuffs in quantities which could endanger human health…”-> in other words this means: No problematic migration is permitted.; 2. No unacceptable change in the composition of the food; 3. No deterioration in the organoleptic characteristics.
The GMP Regulation 2023/2006 and its Annex „Printing Processes“: Printing inks applied to the non food-contact side of materials and articles shall be formulated and/or applied in such a manner that substances from the printed surface are not transferred to the food-contact side through the substrate or by set-off in the stack or the reel, in concentrations that lead to levels of the substance in the food which are not in line with the requirements of Article 3 of Regulation (EC) No 1935/2004.
Currently the Swiss Ordinance on materials and articles, with the subchapter packaging inks, is the only printing ink specific regulation, which has been implemented. It contains a positive list on substances to be used for the manufacturing of printing inks. (A 10 ppb limit applies for list B substances.-in case of questions)
“EuPIA Guideline on Printing Inks applied to the non-food contact surface of food packaging materials and articles”: Considering the fact, that despite the existence of a framework regulation applicable on all packaging materials for food (see above EU-Framework Regulation (EU) No 1935/2004) until now no specific community legislation on printing inks intended for food packaging is available, EuPIA has issued a guideline for his member companies. It contains detailed recommendations, based on current European legislation, on how printing inks should be formulated in order to meet the requirements of the framework regulation.
Specific brand owner have often additional requirements, which are beyond the legal ones. They set their own standards. Frequently own exclusion lists on specific raw materials (ingredients; substances) are set (e.g. for specific pigments, photo initiators, acrylates and solvents).

23. Regulatory Requirements
Additional regulatory requirements
Eco-labels (e.g. EU-Eco-Label, Blue Angel, Nordic Swan)
Toys → legal provisions; requirements of brand owners
Cosmetic, pharmaceutical or tobacco packaging → see above
Others: biodegradability, origin of renewable raw materials, no use of genetic modified materials or of conflict minerals…
The selection criteria for printing ink raw materials and the special requirements for materials used in the production of food packaging as described before are not the only ones. With the following we want to give you some examples for additional demands:
So called Eco-labels are getting more and more important. There exist several Eco-labels which are all not made for the ink itself but for the final product , of which the ink is a constituent. Most important labels are „EU-Eco-Label“, „Blue Angel“ and the Scandinavian „Nordic Swan“. The exact requirements of each of those labels are not equivalent and are in some cases specific for certain countries. This can mean that an ink which can be used for making a „Nordic Swan“ compliant product, can not be used for producing a „Blue Angel“ compliant product or vice versa.
Printing of toy packaging is also an important application range for which strict regulations apply. There exist legal provisions and common standards as well as special requirements of brand owners.
The same is true for cosmetic-, pharmaceutical- or tobacco-packaging. In addition to legal requirements you will always find special demands of different brand owners.
And there are many other requirements which make the complexity of choosing the correct raw materials for an ink system even bigger. With the following there are given some more examples:
Biodegradability, origin of renewable raw material, no use of genetic modified material or of material of animal origin, no use of conflict minerals or materials containing conflict minerals….
This summary is definitely not complete. At the end it should show that there exist special demands for more or less everything. Therefore a very close cooperation of printing ink producer on the one hand and printer or converter or brand owner on the other hand is inevitable for making sure that all relevant aspects are covered.

24. Summary Printing inks bring color into our world.
Printing inks are crucial for the exchange of information.
Printing inks are developed with a sense of responsibility and know-how.
Printing ink brings color into our world and it is absolutely crucial for exchanging information.
It can be said that there exists a more or less endless number of different printing ink recipes in the market.
This enormous variety is on the one hand the result of variety of technical requirements of different printing and converting processes. On the other hand it is caused by the continuously increasing variety of regulatory demands.
It is possible to find or to develop the ideal ink recipe for more or less each and every specification. Printing ink producers did create the necessary knowledge – and we still do in our daily business. The key for recommendation of a perfectly fitting product is a good communication along the whole supply chain. If from the very first the exact requirements are clearly defined for everybody, there is no room for bad surprises.