Flexography in Package Printing

April 22, 2010

multipage

Improvements in the press room
Even the printing process is undergoing improvements, thanks to increased levels of quality controls available from some press manufacturers. In the world of flexo, the time taken in setting and adjusting a production run is a key factor when it comes to evaluating productivity. On top of this, returned orders affect the reputation of a company and increase its costs. With these issues in mind, new high-performance quality control systems make it possible to guarantee that 100 percent of the production from a flexo printer meets the quality standards set by the customer, while simultaneously cutting set-up times and reducing waste.

Thanks to the high level technology employed by these quality control systems, a wide range of print defects down to just 3 square mm in size can be detected. When used in carton board application, the sheets containing elements identified as defective are automatically ejected, highlighted, or ignored by the press, according to the settings defined for the detection zone the defects occur in and the level of quality chosen by the operator.

Philippe Kunz, Marketing & Communication Project Manager at Bobst, another Flexo4All core member, comments: “iQ300, the quality control system developed by Bobst, is the essential final filter, verifies the production and  ensures that the printing reaches the quality needs of even the most demanding end-users.”

Where flexo beats offset
The cardboard packaging market is undergoing a period of renewed development. This is true in industrial countries, where the standard of living is high, as well as in developing countries, including large Asian countries such as China and India. As a consequence, within the printing and converting industry, investment in innovative technology is going to grow. New alternative solutions to offset printing appear, offering streamlined production processes, excellent qualitative results, and interesting profit outlooks. Flexo printing technology results are particularly convenient when low volumes of production are required, often within a limited expense budget. An example is the pharmaceutical industry, whose large orders include such a range of variations that each project is regarded as a separate order.

In these kind of packaging applications, flexo printing provides a higher level of chromatic balance and color constancy than the average offset. “The best results are obtained by flexo printing with UV ink.” states Paolo Grasso, Area Manager at OMET, again a Flexo4All core member. “Without denying the excellent printing quality of sheetfed offset printing used for luxury packaging, many packaging processes can be transferred to flexo lines with significant monetary and time savings. This concept is breaking into many paper product companies as it provides immediate benefits to those who opt these solutions.”

Flexo benefits on inking edge
The latest developments of polyurethane (PUR) resins have opened up new applications. The successful increase of flexography printing of, for example laminates, is highly correlated to the almost unlimited possibilities of the PUR synthesis. Modern polyurethane resins are synthesized through the complex combination of various intermediates by multi-step reactions. Thus high-molecular, film-forming resins are formed exhibiting excellent adhesion properties, high solubility in alcohol, lowest solvent retention, high blocking and sterilization resistance. Properties of polyurethane resins can be varied in multiple ways by selecting specific intermediates. Tailor-made PUR resins can be manufactured and their characteristics can be adjusted exactly to the respective requirements.

“Over the last years intensive laboratories researches brought polyurethane (PUR)-based color inks to be used in flexo printing opening to this technology new possibilities previously reserved only to gravure printing,” says Thomas Bastian, Marketing Director at Siegwerk. “PUR inks exhibit excellent printing results and can be universally applied to a very wide range of substrates. OPP, pre-treated PET, as well as OPA, barriers films coated with SiOx and AIOx can be printed directly with PUR inks.”

About Flexo4All
Flexo4All is a strategic cooperation which combines worldwide expertise from independent companies—suppliers to the graphic arts and packaging printing industry. Born to be a strategic cooperation and not a commercial joint venture to sell complementary products or services Flexo4All aims at:
• Encouraging networking within the flexo industry to create active cooperation among all partners;
• Connecting the competence of all members to deliver knowledge and added value solutions worldwide;
• Promoting the value of flexography as the best technology to satisfy all printing needs;
• Achieving improved and sustainable service for the flexographic packaging printing industry.