Why we should not be using toluene-based inks

Threats to safety in printing inks

toluene-based inks

Toluene is an industrial solvent that is widely used by the chemical industry. In India, a vast majority of package printers use toluene-based inks. It is estimated that 90% of the inks used in rotogravure printing, which is by far the predominant printing process used by the Indian flexible packaging industry, are based on toluene formulations. The concentration of toluene in printing inks can be as high as 40%. This is very unsafe and we explain why.

Solvent-based inks (also called liquid inks) are usually made up of 4 major components: solvents (50% – 70%), binders (15% – 30%), colorants (12% – 20%) and additives (4% – 8%). The major threats to safety in printing inks come from toluene and mineral oils.

There are two ways in which toluene can be unsafe. One is through migration into package contents and the other is by inhalation and exposure to it through handling of toluene-based inks by operators and other workers during the printing process and subsequent conversion processes.

One of the major causes of concern is a migration of ink constituents into the products contained in the package. Almost all printed structures contain a certain amount of retained solvent (in this case, toluene). This retained solvent migrates by diffusion through the package substrates and physically transfers into the product. Migrants below 1000 Dalton can penetrate human cell membranes. When a product containing migrants is consumed or comes into contact with the skin or other membranes, these migrants can get absorbed by the human cells. Most flexible packaging substrates do not possess adequate barriers to diffusion of toluene (only aluminium foil and glass are considered total barriers to diffusion; even rigid materials like PE/PP/PET/PVC used in bottles are prone to diffusion).

Toluene is known to have several deleterious and harmful effects on humans. Some of these are listed below:

Breathing difficulties
Eye and throat problems
Memory loss
Skin irritation/Dermatitis
Suspected damage to unborn children
Ototoxicity – imbalance, the hardness of hearing/anacousia

As one can see, this list is quite frightening and it is surprising that toluene-based inks are even allowed to be used in the first place.

Admittedly, toluene has a lot of things going for it from a functional point of view. It is a very effective and cheap solvent with a low boiling, quick evaporation and faster drying properties (this leads to easier handling, lower energy consumption and faster printing speeds). It also cuts through film surfaces and enables excellent print adhesion and anchorage. However, its toxicity is too serious to accept from a safety point of view.

To an extent, the proliferation of toluene-based inks in India is due to its being cheaper and more convenient to use than other ink systems as well as its making life easier for the ink companies.
If we look at the situation in the developed countries like the USA and Europe, most print unions and workers’ unions will not even agree to run toluene-based ink formulations due to the hazards posed to their workers/operators by them.

It is only now that a few ink companies in India are offering alternative ink systems albeit at higher prices. The printing industry and brand owners must realize that this additional cost is well worth bearing in view of the hazards posed to consumers and operators.

So, technically, what are the alternative ink systems that can be used? Inks that use alternative and safer solvents can provide the solutions. These solvents could be ethanol/alcohols, ethyl acetate/esters or methyl ethyl ketone (MEK)/ketones. All of these are now being offered by the better ink suppliers.

The impact, resilience, and growth of responsible packaging in a wide region are daily chronicled by Packaging South Asia.

A multi-channel B2B publication and digital platform such as Packaging South Asia is always aware of the prospect of new beginnings and renewal. Its 16-year-old print monthly, based in New Delhi, India has demonstrated its commitment to progress and growth. The Indian and Asian packaging industries have shown resilience in the face of ongoing challenges over the past three years.

As we present our publishing plan for 2023, India’s real GDP growth for the financial year ending 31 March 2023 will reach 6.3%. Packaging industry growth has exceeded GDP growth even when allowing for inflation in the past three years.

The capacity for flexible film manufacturing in India increased by 33% over the past three years. With orders in place, we expect another 33% capacity addition from 2023 to 2025. Capacities in monocartons, corrugation, aseptic liquid packaging, and labels have grown similarly. The numbers are positive for most of the economies in the region – our platform increasingly reaches and influences these.

Even given the disruptions of supply chains, raw material prices, and the challenge of responsible and sustainable packaging, packaging in all its creative forms and purposes has significant headroom to grow in India and Asia. Our context and coverage engulf the entire packaging supply chain – from concept to shelf and further – to waste collection and recycling. We target brand owners, product managers, raw material suppliers, packaging designers and converters, and recyclers.

In an admittedly fragmented and textured terrain, this is the right time to plan your participation and marketing support communication – in our impactful and highly targeted business platform. Tell us what you need. Speak and write to our editorial and advertising teams! For advertisement ads1@ippgroup.in , for editorial info@ippgroup.in and for subscriptions subscription@ippgroup.in

– Naresh Khanna

Subscribe Now
unnamed 1


Subscribe to our Newsletter

As 2023 begins and FY 23-24 unfolds, will you support us?

What lies in store for the packaging industry in India and South Asia this coming year? Inflation, disruption of supply chains or environmental regulation? Or the resumption of high rural demand, continued investment and industry consolidation? Whatever happens, Packaging South Asia will be there, providing clarity and independent technical and business information in India and South Asia and around the world. We are a compact Indian organization bringing a window of fair and rigorous technical and business information that the industry can access this year and beyond. Please support us with your advertising and subscriptions, to keep us going and growing.

Thank you.

Previous articleDIC India focuses on safety in working environments
Next articleToluene-free inks are available
S. Chidambar is an engineer and management consultant, who is one of the India's best known professionals in the Packaging and Plastics industries. He has been the CEO of four leading Packaging companies and his clients include some of the industry's leading organizations both in India and abroad.He writes extensively on Packaging,Plastics,Printing/Conversion and Communications and has been visiting faculty to IIP and several other mangement institutes for many years.He has pioneered the development of several hi-tech materials and applications.


  1. Good info.
    I was checking if i should include the “retained Toluene Level” in the COA from my supplier when i read this. Definitely will need to include and will consider talking to the management on the toluene free ink usage.



Please enter your comment!
Please enter your name here