Everything you need to know about humidification in packaging factories.
Why humidify for packaging factories?
Optimal temperature and humidity levels play a very important role for packaging factories. By controlling the relative humidity you ensure fewer shutdowns of the production line, avoid material losses, poorly finished products and electrostatic discharges.
Proper humidity is important if you want to maintain optimal product quality:
Adhesive labels must convey the correct messages and must be able to be used for as long as possible without degrading. Tight control of register and dot density, especially in multipass work, is essential. Labels face several problems due to incorrect humidity levels: tight edges, curl and creasing. High humidity can affect the quality of the print, the adhesive strength of the adhesive, and can cause the labels to fade quickly, making them useless. Maintaining a humidity level of 50-55% RH and a proper temperature can help avoid these problems.
For premium products, volumes are lower and very high quality is required, often including metal foils and films applied to paper labels. For foil and film, electrostatic prevention is essential for straightforward handling and adhesion. Whilst the threshold for electrostatic control is 40-45%RH, the conditions required for printing are such that 50-55%RH is commonly maintained throughout the area.
Film processing and printing
The packaging films are particularly sensitive to the accumulation of electrostatic energy, from the extrusion process, to the printing process up to the lamination process. Because films are not usually hygroscopic like paper and cardboard, higher levels of humidity are needed to help disperse electrostatic charges. A humidity level of 50-55% is typical, but it is recommended to keep the relative humidity level at 60%.
Many types of adhesives lose moisture in an air environment that is too dry, thus adhesive pads have problems bonding, and labels, for example, do not stick well to the substrate (eg glass, cans, etc.). Typically, adhesives are in balance with the paper, so a moisture level of 50-55% RH helps solve these problems.
Cartonboard and corrugated board
Thicker papers and boards are less susceptible to curl and electrostatic problems, although not immune from them, so raw material and blanks are best stored and worked at 50-55%RH. More significant is the problem of cracking on the external face of folds in thicker papers and boards, due to loss of flexibility of dry boards. This is most obvious on printed work, where the white substrate is revealed, inevitably meaning the batch is rejected. Again, storage and converting at 50-55%RH will typically address the matter.
Embossing paper and board
The flexibility and strength of the paper are affected by the moisture level. The paper is hygroscopic so it absorbs moisture from the air, thus changing its properties when the humidity level is lower or higher than the optimal required range, paper can wrinkle due to water absorbed from the air and can no longer be used or can become too dry when the humidity level is too low. Embossing exposes the paper to the risk of cracking and tearing, especially in the newly created thinner areas of dry paper. Whether it is at the paper supplier or in production, a level of 50-55% relative humidity helps maintain the optimum moisture levels and counteract this problem.
Benefits of Condair humidification in the packaging industry:
- Extensive experience in all packaging process from projects around the world
- Comprehensive product range to precisely meet production requirements
- Low energy and low maintenance humidification solutions
- High production speeds and less downtime of machinery
- Reduces electrostatic build-up and subsequent discharge
- Prevents dimensional changes to materials and problems of mis-register
- Prevents cracking along folds
Our packaging clients include
- Mayr-Melnhof Packaging, France
- Amcor Tobacco Packaging, Russia
- Hewlett Packard, Spain
- Tetra Pak, China
- SCA Packaging, Sweden
- Marinetti-Packaging, Chile
- MM Packaging, Germany
- Tralin Pak, Mongolia
We want to be a competence center that offers optimal solutions for your production unit. With a team of specialists consisting of engineers, technicians and technologists with extensive experience in the field, we offer consultancy, service and practical seminars at any level. If you are looking for a humidifier or have any other questions, do not hesitate to contact us.