The paper sack is a generally established and wellproven packaging solution that has been in use for many decades. But precisely because of this long history, the paper sack is nowadays often regarded as an unsophisticated and outdated product. This image is unjustified, says GemPSI, the Gemeinschaft Papiersackindustrie e.V. (Paper Sack Industry Association), because the paper sack has undergone constant refinement in accordance with the rising demands placed on modern packaging. The industry’s innovative strength and technological developments have made it into a sophisticated high-tech article with numerous positive characteristics that are perhaps not obvious at first glance. The product is indeed a real “sack full of ideas”, which never ceases to surprise. Under this motto, GemPSI launched a promotion initiative at the beginning of 2014. What is behind this? Alfred Rockenfeller, Chairman of GemPSI describes current trends in paper sack production.
ZKG: What is it exactly that makes the paper sack into a high-tech article?
Rockenfeller: Firstly, the porosity of the employed Kraft paper, a feature which has been continuously improved over the years. This porosity enables problem-free venting during the filling process, without requiring complex and cost-intensive air extraction systems. The air contained in the sack simply escapes through the paper – naturally without allowing loss of the material being filled. This allows filling speeds of up to 6000 sacks per hour. The amount and cost of the paper used are further positive features that place paper sacks ahead of the field. Paper requirement per sack has been reduced by 25 % in recent years – and that despite the fact that sack stability has remained the same or has even been improved. Depending on the particular product involved, the weight ratio of paper sack to contents can be up to 1 : 300. Hardly any other packaging product can achieve this efficiency. And that saves not only on sack material, but also on transportation costs. Another important point is that paper sacks are hardly ever standard products covering every possible application, but almost always are specially designed to suit the particular material to be packed before they are put into mass production – more or less comparable with a made-to-measure suit. We can therefore say that the paper sack is quasi re-invented every day.
ZKG: Nevertheless, practical experience shows that the paper sack is inferior to other types of packaging when it comes to other important aspects like protection against moisture and shelf life. Are there any innovative solutions to these deficiencies?
Rockenfeller: Protection against moisture has up to now been a characteristic that has been mainly associated with other packaging products. But that does not mean that the paper sack industry offers no solutions in this point. New developments in paper technology, in adhesives and in printing processes now mean that paper sacks also offer good protection against dampness and moisture. Such high-quality paper sacks can also be stored outdoors without risking softening of the sack or clumping of the contents during the first rainfall.
Moreover, particularly effective protection – even during especially adverse weather conditions – can, if required, be achieved by incorporating extremely thin plastic or aluminium barrier films into the paper sack. In combination with the resultantly improved stability of the Kraft paper, both types of barrier film enable filled paper sacks to be stored without problem for between 6 and 24 months – or even more.
ZKG: What other prejudice concerning the paper sack would you like to dispel?
Rockenfeller: It is often said that the paper sack causes problems of higher dust generation or reduced cleanliness. However, in reality a whole range of developments has eliminated these problems. Modern valve technology assures dust-tight sack closure and modern sack-opening systems prevent dust generation. This qualifies the modern paper sack for use even as a packaging solution for dusty products intended for application in areas that have to stay very clean during the processing.
ZKG: Does that mean that the modern paper sack is unconditionally suitable for all bulk materials?
Rockenfeller: Maybe not for all, but certainly for more materials than some people think. For each product there is a packaging solution that best meets the individual requirements. Selection of the most suitable packaging should always take full account of all the relevant parameters. In its entirety, the paper sack offers a unique combination of functionality, cost efficiency and environmental compatibility, paired with outstanding filling characteristics, good protection of the product and a wide range of design possibilities. This is an overall package that is second to none.
ZKG: Thank you very much for this informative discussion.