Last month, I reported on the important early days of the introduction of UV curing into Australia, and continue the story this month. I left off just where metal decoration had come into its own, as the physical replacement of a giant travelling hot air oven by a conveyor belt with a UV dryer that extended about four metres was simply too logical and cost effective to disregard.
At the time, inks were still limited in performance by the small number of vehicles that were available, however, sufficient experience had been gained with UV materials to clearly indicate that some components were simply too reactive towards people to be safely used in commercial quantities.
Led by the then Society of British Printing Ink Manufacturers (SBPIM), a convention was adopted initially in the UK that materials that could cause skin irritation (as measured on the Draize scale), or that were chemically potentially toxic would be banned from inclusion in inks and coatings.
The leading manufacturers in Australia quickly picked up this convention, and even in the seventies, UV inks made in Australia were among the earliest in the world to place a high focus on occupational health and safety. (It was frustrating at times to observe that many imported products of the time did not).
To return to the historical perspective; by the mid-seventies, the foresight of a couple of label printers brought about a most successful marriage of UV cure and self-adhesive labels, the first industry sector to ultimately embrace UV across all of its areas.
Allan Dabscheck of Austral Gold Stamping in Melbourne (now Austab Labels), and Sid Staas of Assta Labels in Sydney, (both most deserved inductees into the Latma Hall of Fame), were the true pioneers of UV label printing, and after one look at the alternate technology, it was not difficult to realise why.
My first exposure by Allan to a label operation was a real eye-opener. A Superior letterpress machine at one corner of a long room was printing what were effectively conventional heatset inks onto self adhesive roll label stock, which was then festooned diagonally across the room under several infra-red heaters to a reel stand, where the labels were re-reeled and the swarf removed.
Unfortunately for the process, and for all label printers at the time who were forced to rely on similar arrangements, physics got into the act, as if sufficient heat was put into the print to dry the ink, the labels curled so badly they couldn’t be re-reeled, or if the stock was cool enough to re-reel, the inks blocked!
A few weeks later in the same pressroom, the substitution of a metal "oven" (looking like a letterbox with two slots) with a single six inch Hanovia UV lamp inside dried the trial UV inks completely and the reel stand, now one metre from the press re-reeled the labels perfectly.
Throughout the label industry, subsequent refinements were added such as variable-power lamp control, shuttering of the lamps to stop the web burning when the press stopped, multi-colour printing, and finally (the big breakthrough) rotary presses. All of these combined to make the adoption by the label industry of UV curing an industry-wide phenomenon, such that by the end of the decade, barely a single press remained that still printed oil based inks.
While the label industry was absorbing UV technology, another quiet revolution was also taking place in the screen-printing arena.
Led by the energy and insight of Ron Mason of Mason Duflex, the screen printers of Australia quickly added UV curing to their armoury of products, particularly for printing on non-porous substrates.
Initially it was thought that UV lamps would not be able to cure right through the thick ink and coating films produced by screen printing, but the development of higher pressure Mercury arc lamps of increased output, and new photo-initiator systems for ink formulations, when coupled to relatively long exposure times enabled screen to become the third success story of the UV era.
Roller coated UV gloss coatings were the next major development, both technologically and commercially, and in this area the leaders were Gavin Hogan of All Kotes, and the late Phillip Gude; both men ornamenting the mould of innovators who envisaged an embryonic growth industry, and wanted to be a part of it.
As a pioneering manufacturer of the coatings themselves, I look back with some embarrassment on the brittle, yellow, smelly coatings that our customers had to endure before commercially useful materials were developed.
For instance, when a new type of high-efficiency photo-initiator first became available, I recall testing it in a coating formulation at Mr Gude’s Rooks Road factory. The brief test looked fine, so we arranged a full sized run. Unfortunately, the new material was a sulphur based chemical, and the by-product of the curing process was an overpowering smell exactly the same as that generated by humans who have been eating sauerkraut and drinking lots of lager the day before! I could only sympathise with the coater operator who had bravely finished the job with all doors and windows open on a freezing Melbourne winter’s night.
Following a brief detour into Electron Bream curing by Tetra Pak, which is really another story in itself, the big development that had been pending for some years, was the commercial adaptation of the UV curing process to sheetfed lithography.
The outstanding contribution to the development and commercialisation of the UV litho application was through a company known as the Marketing Machine, run by Robert Paterson and Tony Grey. From the beginning of the 1980s, the enthusiasm and expertise of these two pioneers led what was to become a tidal wave of technology.
The concept of a rapid turnaround printing business based on instant curing of inks on almost every substrate that could be run through a litho press became the model that has that subsequently transferred to printers of all kinds of sheetfed work.
So that is where the historical note ought to end, as the last twenty years are also another story, of consolidation, of expansion, and of adaptation of the "new" technology of UV cure to almost every part of the printing industry.
Many happy returns UV cure; your best years may be yet to come.
Rod Urquhart works at Monash University where many aspects of the industry are being studied. He is based in Australia.
Contact Rod Urquhart via email: email@example.com