calvasol® functionalisation
kalwar's expertise in nanotechnology is opening up a range of new possibilities for pre-treating and coating smooth film surfaces.
Applying finishes to smooth film is generally extremely difficult because their surfaces are unable to adequately bond with inks, adhesives or metals. To remedy this, their surface’s chemical and physical properties are modified by, for example, pre-treating them in a corona system. As surface properties are increasingly required to meet ever higher quality standards, kalwar developed a technology to meet this very need: kalwar calvasol®. This technology involves the application of special layers of reactive liquids and/or gaseous substances to a film’s surface in an inline process. This is achieved by introducing an aerosol, which subsequently settles on the plastic surface, into the corona discharge field by means of an air or gas stream.
The corona discharge then triggers a number of reactive mechanisms that produce a change in the film surface’s chemical composition. Depending on the type of liquid and aerosol carrier gas used, the aerosol droplets will form active centres in the form of functional groups and radicals on the plastic surface to be treated, which will then act as reacting agents for the substances to be applied. This method can also be used to apply layers of polymerisable substances.
![[Translate to English:] geschlossene calvasol® Funktionalisierungsmaschine](/fileadmin/_processed_/8/c/csm_funktionalisierung_01_e0b5dcad55.jpg "[Translate to English:] calvasol® Funktionalisierung")
![[Translate to English:] geöffnete calvasol® Funktionalisierungsmaschine](/fileadmin/_processed_/1/2/csm_funktionalisierung_02_009c77376f.jpg "[Translate to English:] calvasol Funktionalisierung")
New possibilities opened by calvasol®
Quite often, even just applying ultra-thin nano-range layers to a film is sufficient to increase its antistatic, barrier and adhesion properties to the required level. If the aerosol substance is not applied through the corona discharge field, it will lead to the formation of laminar air flows between the carrier roller and corona electrodes even at web speeds of as little as 1 m/min, which will prevent the substances from adhering to the surface.
![[Translate to English:] calvasol® Funktionalisierung](/fileadmin/_processed_/8/1/csm_CFT-Corona_01_4a7eb5df9b.jpg)
calvasol® is opening many new possibilities for pre-treating and coating surfaces. It can also be used for treating very thin films with widths of up to 10 metres and at speeds of over 400 m/min. PET has a surface resistance of ›1013 Ohm. Applying an antistatic agent with calvasol® reduces it to 108 Ohm.
One of the key surface treatment steps in the functionalisation of OPP film is the application of a formula that promotes adhesion. If pre-treated with just corona, it will loose its adhesion strength, which is initially high, extremely quickly. The functionalisation generated with calvasol®, by contrast, increases adhesion by up to 60 mN/m and for a number of months.
calvasol® is a highly effective and cost-efficient surface coating process because it applies substance within the nano-range and is consequently extremely economical. It is furthermore also suitable for processing virtually all soluble coating substances, including those designed for the food industry.
The latest generation of calvasol® systems are considerably more economical in terms of energy and substance consumption, which means they generate substantial savings over wet-chemical coating and varnishing processes. This not only benefits the environment, but also reduces production costs such as for energy by up to 90%! This equates to a significant reduction in carbon emissions, which may also support eligibility for government support measures.
Our team of experts would be happy to analyse the potential savings for your specific production process. These will not just be derived from lower energy use, but also from higher machine utilisation and lower additive and ink consumption, and are likely to be higher than you will expect.
Please get in touch for more information – we’re happy to help.
