Putting the PUR in perfect binding

Perfect binding is rising in popularity as case bound books and photobooks increase in demand and PUR has changed accordingly.

Looked at in a certain way, the rise of short run books has been inevitable, spurring demand for perfect binding and now hard cover books. For many printers bringing perfect binding in house has followed the same trajectory as laminating: the same arguments about ease of use and eliminating set up and transport costs apply, especially as runs get shorter.

This is due partly to the long tail effect, where thanks to digital printing publishers can keep books in print long after they would otherwise have disappeared; there is the rise in self-publishing and the micro publisher able to operate thanks to digital networks; there is the photobook and there is substantial growth in the use of case bound books for promotional purposes, driven in the main by developments in digital printing.

And where the presses have led, the binding technology has had to follow, spurring development of a huge range of binders designed to match short run digital printing. They range from sub £10,000 largely manual machines to highly automated binders from Muller Martini and Kolbus capable of handling hundreds of small runs a day. What each has in common is summed up in three letters: PUR.

Polyurethane Reactive glue made its debut in the printing industry in the mid 1990s, before the digital revolution really took hold. It promised a stronger bind than standard hot melt glues, but required careful handling and understanding.

There were products in the glues that are at best irritants, hence lines needed extraction systems to duct away fumes from the glue. The glue reacts with moisture to form the tight bind, changing molecular structure to form the necessary bind. But this meant that moisture content in paper and in the atmosphere was critical. And the pace of reaction at that time was slow. PUR bound books had to be stored before trimming and shipping, compounding the humidity issue.

Over the last 20 years PUR glues have taken huge strides, though there are legacy issues to be aware of. Drying times are faster, but the books should rest overnight before shipping or opening; the glues may have eliminated the worst of the irritants, but should not be used in an enclosed space; and the aggressive nature of some of the components mean strict housekeeping measures are necessary to avoid corrosion of the valves and melting tanks, applicator wheels and so on.

And the glues remain more expensive than hot melts.

Nevertheless the strength of bind and that PUR overcomes the problems that EVA hot melt glues have with digital print and coated papers has ensured that PUR has become a term that has migrated from the industry into the wider community. Just as customers were wont to specify Heidelberg printing or Scitex page make up, they will now demand PUR binding even where they do not fully understand the implications nor if it is necessary.

PUR has become the defacto standard for short run binding. At the last Drupa, Kolbus showed a complete line for book production, both soft and hard cover based around the KM200 with self adjustment for thicknesses of successive books. “It has taken time for the market to understand its potential,” says UK managing director Robert Flather.

This goes also for the case making and casing in line that was shown at Drupa. As each step of the line is both linked and independently controlled, as soon as one part of the task is complete and the product moved to the next station, make ready begins for the next book.

“For us, growth in PUR has been at the expense of sewing in recent years,” he says. “It has not taken so much out of hot melt as these adhesives have improved.”

Muller Martini, however, is noting that all the inquiries relate to PUR. A lot of trade binding customers have gone over to PUR, with Cliftons, Fastline and Khromatec all operating Acora binders with PUR. “A lot of people think that PUR is going to take over,” says UK sales manager David McGinlay. “But it’s not the be all and end all. It doesn’t offer the strength of sewing and there are housekeeping issues that not all users understand.

“PUR is a quite aggressive substance and will attack all the exposed parts of a machine. Whenever we sell a machine we put a service contract in place to ensure that we are maintaining the system ourselves, that we check the valves and parts we have learned about in our 15 years’ experience of PUR. The health and safety aspect is vastly improved, but you just have to be careful in working with it,” says McGinlay.

The company is selling binders from the high speed Corona machines to smaller Acoro A4 running at 4,000 cycles an hour. The Alegro, which was introduced at Drupa 2012, has notched more than 60 installations worldwide since.

It is capable of handling both digitally printed and offset books and thanks to the modular design strategy that Muller Martini is working with, additional modules can be added to keep pace with market changes says the company. It offers that choice between PUR and hot melt.

PUR demands a much thinner layer of glue than hot melt where the idea is to penetrate the fibres of the paper as much as possible. This is why notched binding adds an extra degree of strength to this method of binding. PUR on the other hand cures to whatever it is applied to and once it has gone off will hold fast. Hence heavy layers of PUR glue are a waste, not a benefit. The recommended layer is 0.2-0.3mm thick. Consequently on long runs the cost of the PUR adhesive can become a factor in the unit cost of production.

The nature of PUR is why Muller Martini is firm about the need for service contracts. Nozzles, whether on top end or entry level machines, can be expensive components to replace and their loss will affect production. “Those customers that have declined a service contract have found out to their cost that this is a false economy,” says McGinlay.

The glue tank is another of the components on a PUR machine that will be attacked by the adhesive and will need replacing over time. Wohlenberg is the second binding equipment manufacturer from Germany and like Kolbus offers system level machines complete with gathering sections and multi clamp binding sections.

But it has also developed a standalone four-clamp machine, the Quickbinder specifically for the short runs that are schedule wrecking to load on the long machine and which are either pregathered because of they are printed digitally or may even be hand collated.

“We think that the Quickbinder is the best in class machine, with everything automated and designed for a quick change between PUR and hot melt. We can also handle PVA, which gives the strongest bind for lay flat applications,” says Roger Cartwright, Friedheim International’s binding specialist. Like other suppliers that have long experience in binding systems, Wohlenberg uses an open tank system. “The nozzle systems are sold on ease of use and cleaning, but they are not the be all and end all,” he argues.

“With the roller applicators the operator can see what glue is being applied, which is not the case with the nozzle technology and as PUR requires a very thin film to work best, operators can easily be nervous about the amount being applied and so increase the flow to the nozzle, As a result they lose the flexibility in the bind and increase the costs of binding. Each system has its benefits,” says Cartwright.

One of this is about future proofing. Cartwright explains that adhesive companies have developed non reactive polyurethane glues, but that these are not yet commercially available. Switching the open tank systems to run with this new glue will be simple, while there may be viscosity issues around the nozzle technologies. In the meantime PUR remains the strongest glue generally available, with developments reaching the market that have reduced the notoriously long resting time. A complete cure is now possible in 12 hours and only needs eight hours before being handled ready for shipping.

This opens the way for printers to offer a true next day service for perfect binding Jason Seaber points out. He is the technical sales director at IFS which distributes the market leading Horizon BQ470. The four-clamp binder comes into almost every conversation about perfect binding and IFS has sold more than 150 across the UK. Slightly more than 60% are configured as hot melt machines, but can have the option of adding a PUR tank.

Seaber explains the appeal: “It’s compact, it’s fully automated and delivers value for money. But it is the bind quality which sells the machine. There is the same strong nipping action as on a system binder which results in a high quality bind. “At the recent Print Efficiently event, a prospect had brought some sections for us to bind and said: ‘I’m staggered. I never thought the quality of the binding would be as good as this, better than the work we send for trade binding. How can that be?’”

Part of the appeal must be the move from the Horizon single-clamp binders when a company has outgrown the productivity of the simpler machine. The interface remains the same and one man operation can produce three or four times as many books. And each book can be a different thickness though the automatic set up, Seaber points out. The BQ470 is a machine that has gone to trade binders as much as to litho or digital printers, thanks to the quality of the bind. It relieves the pressure on the larger machines for shorter run work that comes in from the trade and with PUR can cope with the growth in digitally printed pages.

Perfect Bindery Solutions is introducing the UK to the Italian made Risetec machines which like many Italian engineering companies offers well conceived solutions to production issues. Managing director Steve Giddins points out that the BQ470 cannot offer true end papering and gauzing for example which the Risetec can. “Even the single clamp machine is designed for end papering,” he says. “For specialist books a hard cover bind is a must, nobody wants to pay that amount for a paperback.”

A number of UK players are interested in the the capabilities of the Risetec machines, including the short run sewing capabilities of the Smyth lines that PBS also sells.

“Where the format of the book is too large sewing is needed to hold books together where PUR can’t,” Giddins says. But the Risetec concept is creating the interest with production at 600 cycles an hour for the single-clamp machine and 1,300 for the four-clamp. “We have a number of customers that are very interested and we have sent piles of work to Italy to show customers how these run,” he says.

The design of the open tank systems means that any glue left in the tank has to be thrown away at the end of the day. Experience in turning off the flow and running down the amount in the tank, like stripping the rollers of ink on a press, will reduce this waste to minimal amounts and shallow tank designs also reduce the amount that is discarded.

Nozzles systems do not suffer this problem, but do need to be protected at the end of the day, meaning that at start up any protective wax or glue in the applicator has to be purged before use.

The appeal is for digital print because hot melt does not take easily to either fuser oil, colour printing into the gutters or coated papers. With conventional uncoated papers made from mechanical ground pulp, the preparation is designed to open the paper fibres and allow the EVA glue to penetrate and spread to provide the strength of bind.

This does not work on coated papers produced from woodfree pulp nor where other materials come between the fibres and the glue, hence the need for the PUR approach to provide the strength required. But PUR glues are significantly more expensive than EVA products, the PUR application systems can add significantly to the cost of the binding machine.

Watkiss Machinery has taken note of this and its Mamo perfect binder does not use PUR. “We know that with PUR comes with considerations of health and safety, the ventilation needed because of the PUR glue, which add to the cost. The Mamo binder is ‘near PUR’, which we believe is a much more cost effective way of going about this kind of work,” says marketing director Jo Watkiss.

It uses an enhanced EVA glue which shows results that are close to PUR and well above standard hot melt in pull tests. Watkiss will invite prospects to send their work in for testing. “Every job is slightly different so we can’t promise that every job performs the same on every digital press, which is why we encourage printers to try it,” she says. Technical sales manager a href=”http://bit.ly/2nzswed” target=”_new”>Chris Page agrees: “It is more than suitable for 90% of digital print jobs, and because it costs less than £10,000 is substantially cheaper than anything with PUR.”

While the Mamo is an entry level machine it is still productive. The level below this comes from Ashgate Automation, best known for the Fastbind casing equipment that is hugely popular in the photobook sector. The Finnish manufacturer has long offered a simple adhesive binding product which after two years in development has resulted in a PUR machine, priced below £8,500 and which uses according to Ashgate managing director a href=”http://bit.ly/2nwVFXj” target=”_new”>Lewis Price “no more than a teaspoon full of glue”. He adds: “It brings PUR to the people producing single books, either as end products or as proof copies before a longer production run. The reaction since we introduced it has been fantastic both from new and existing customers.”

The glue is supplied in a cartridge which makes it easy to switch between hot melt and PUR. He has taken orders, some for multiple machines, and attracted a lot of interest at the recent London Calling where Duplo was introducing two Ultrabind PUR binders. Tony Lock, commercial director of Duplo International, says that the Hungarian designed Ultrabind 6000 is a machine to compete with the BQ470, even though it is a single-clamp only machine. This makes it less expensive that the Horizon, but no less feature rich with powerful nipping action for strength in the bind, 4kW milling motor and enhancements that have been made since the machine was previewed at Ipex.

A key issue that this machine addresses is ensuring the correct alignment of book block to cover, given the sometimes inconsistent image placement from digital presses. “It’s a real issue that trade binders bring up,” he says. However, the most interesting development is in the orbital PUR applicator which is unique. It uses a ring within a ring, both are open at one point, for the outside ring this is at the point of application. As the smaller ring rotates it collects the glue from a closed tank and as the gap lines up with the outside ring, glue is presented to the book spine. The tank remains completely sealed against air ingress and waste is restricted to the very small amount of glue in the gap which is easily wiped away.

To date Duplo has beta installations in the UK and Germany and is starting to take orders for it and the smaller UB 2000 which has the same orbital glue technology, but aims at a lower point in the market where there is perhaps more competition. It is a position where Morgana is strong with the DigiBook products, stretching from the entry level DigiBook 150 to the DigiBook 450. All share the same PUR gluing technology. The most popular machine is the 200 version says marketing manager Paul Williams, with a £28,000 price tag. This is a closed tank machine designed for broken use, in that the machine will go on to stand by if uninterrupted during the day ready to warm the final tank to operational within a few minutes when needed.

PUR is supplied for both side papers and the spine, Williams pointing out that this avoids any risk of cross contamination – “it’s a disaster if they mix,” he says. The company has collected an impressive user list, including photobooks specialist Harrier which has a Kolbus installation for mainstream production and needed something to complement this. It has taken the DigiBook 300 as has Concept Communications. “We find that people can start looking at the 200 and end up with the 300 because they need to handle longer run litho runs as well as digital short run production,” says Williams.

Facing up to Morgana is Terry Cooper Services with a choice between the CP Bourg machines for heavy production and the Premier range for the digital market. a href=”http://bit.ly/2MiBWZo” target=”_new”>Dean Stayne points out that PUR, while in demand is not always the answer. “The adhesive can cost twice as much as hot melt,” he says. “So we will run trials and conduct pull tests on hot melt first. Some are nearly as good as PUR. “It could be that the demand for PUR will fade in the next year or two as the hassle of working with PUR proves too much and as new hot melt glues become available. The Premier with hot melt is at £9,000 not £40,000 and the quality and sophistication of operation is fantastic. Even the more expensive CP Bourg 3302 machines are more popular with hot melt because it does the job now.”

In short, while PUR rightly dominates and has the universal appeal and guaranteed performance that many non specialist binders will want, it is not the only game in town. There should be no assumptions when buying a binder, check work, check price and check ROI. …