Just because a particular product sounds ‘green’, it doesn’t mean that the benefits are truly understood by everyone. Not that it’s all bad either, but there is a lot of misinformation out there. As informed consumers and producers of printed material, designers really need to understand the true environmental impacts of a particular product by digging a little deeper and not endangering the eco debate with ignorance! Take vegetable-based inks for example…
Traditional ink products have long been regarded with suspicion by those who feel that they represent a long-term threat to the environment. Apart from anything else they are very ‘stinky’ and contribute to the unpleasant odour prevalent in some printing establishments.
This suspicion of petroleum-based products is due to a number of factors, which include the ongoing problem of volatile organic compounds (VOCs), which can give rise to photo chemical pollution and in turn add to the greenhouse effect, the depletion of the ozone layer and probably a number of other issues as well. So it’s no wonder that environmental concerns have influenced the way in which some ink makers have tackled the problem and come up with solutions that are both beneficial for the environment and the health interests of printers.
Traditional offset printing inks are mineral solvent-based; however, mineral solvent inks have always contained a small amount of vegetable oil like tung or cotton seed oil. All ink has three main ingredients:
- pigments and dyes
- vehicles, and
The pigments in ink are usually a dry powder or dye that gives the ink its colour, and are mostly made from organic compounds. Pigments are classed as opaque or transparent. Opaque inks are used when trying to cover another colour or coloured paper. All four colour process inks (CMYK) are transparent because they need to allow the colours to visually combine.
The vehicle part of the ink is the liquid that carries the pigment. It also provides drying qualities and binds the pigment to the paper after the ink has dried.
Additives are used to give special properties to the ink, such as reducing the ‘tackiness’ of the ink. Driers, for example, are additives that speed up oxidation and drying of the vehicle. Waxes help prevent sheets sticking and anti-skinning agents prevent the ink from drying on the rollers. Drying is important because printing cannot be handled or used until the ink is actually dry. The first and most important step is for ink to ‘set’, which takes about two hours and then to ‘dry’, which can take up to 24 hours.
Vegetable oil-based inks, contrary to popular opinion, are not ‘new’, as most inks in the very early days of printing were made this way; however they were extremely slow in setting. Because of this need to speed up the drying process in order to provide quicker turnaround times, mineral oil inks were developed.
Now the technology has come full circle, with a great deal of research and development being done to refine eco inks, which has resulted in a new generation based on renewable resources.
New ‘eco ink’ formulations now use soy or linseed oil, which make up about 30 percent of the total weight, as compared to 10 percent with mineral solvent inks, but with a much reduced solvent content. Eco inks have the ability to dry on coated, uncoated or recycled stocks without any drying problems.
For the client, eco ink colours tend to be brighter, the scuff resistance is greater and a higher gloss on coated stocks is evident. The ink film is 100 percent solid and is suitable for most laser printers as well as being compatible for varnishing with UV.
For the printer they are particularly fast oxidative drying, rapid setting and have very good stacking properties, as well as being highly suitable for infrared drying.
At Finsbury Green, 99 percent of our inks and varnishes are vegetable-based and have been for over seven years. This is just one of the many small steps in a complicated manufacturing process that, we are proud to say, has contributed to a reduction of our greenhouse gas emissions – and that’s the point really. Cleaner, brighter and ecoadvantaged!
From desktop magazine.