Applications of KSL film separating powders

Numerous types of film (e.g. composite, sealing and shrink film) and film materials (e.g. PET, PE, PVC, PO, PE/PA/PP) show a natural tendency to stick during production and further processing due to adhesion and electrostatic effects.

These problems occur in different production processes for various products:

• Blown film extrusion
• Flat film
• Film bags
• Sausage casings

Our food-safe KSL separating powders eskal and esstar counteract this sticking tendency. As a result, they enable high productivity during further processing and facilitate subsequent steps, for example, the fully automatic opening of plastic bags.

In the production of film tubes using multi-bubble technology, biaxially stretched multilayer films are produced. They are characterized by high barrier properties, great robustness and high transparency. This makes these films ideal for food packaging.

In this process, the film tube is usually extruded vertically from top to bottom, blown up and then directly water-cooled. In order to achieve high barrier values and great stability, the foil is heated and cooled again in subsequent steps.

As a result of the further heating processes, there is a risk that the sealing layer on the inside of the tube will already bond during production. This is prevented by using KSL separation powders. The powder is sprayed onto the inside of the film tube immediately after extrusion. During the subsequent winding, an additional antiblocking effect is achieved. As a result, subsequent processing steps or handling operations can be carried out fully automatically without disturbing adhesion effects. Moreover, this facilitates the handling of the finished film products for the end user.

eskal – natural calcium carbonate

Because of high temperatures in the vicinity of the extrusion nozzle, we recommend to use our eskal powder made from natural calcium carbonate here. This mineral powder is temperature stable and non-flammable. Consequently, there is no risk of a dust explosion. Due to the usually vertical alignment of the tubular film, rather fine and therefore light powders such as eskal 10 and eskal 15 (plus) are typically used here. The individual grains of these powders are extremely fine, so that they are not visible on the finished product.

For an effective separation effect, it is crucial that the individual particles of a separating powder have approximately the same diameter. Our eskal powders guarantee this through combined grinding, sieving and (air) separating processes. This enables effective separation with a minimal use of powder. The application can be carried out fully automatically with minimal application systems.

Food-grade certification

Our eskal powders are fully suitable for contact with food. Calcium carbonate is widely used as food additive, even for organic food. Corresponding certifications according to European (e.g. 1935/2004/EG; 2023/2006/EG; 1333/2008/EG; 231/2012/EU; 2020/356/EU) and international regulations (e.g. FDA) are available and are renewed periodically. Moreover, our eskal powders are certified as Kosher including Passover.

In the production of flat films, disruptive adhesive forces can affect the production process and further processing. After winding the foil may block. KSL powders effectively prevent this problem and are therefore usually sprayed onto the film surface right in front of the winder by fully automatic application systems. As a result, the powders maximize the process reliability.

A positive side effect is the ability of the KSL separating powders to compensate for possible flatness imperfections of the film. During the production of very long film webs, minimal irregularities in the foil thickness can occur. If these deviations emerge production-related always at the same point across the film web, these imperfections add up and result in an uneven winding.

esstar – native starch

A suitable separating powder counteracts this effect. The more evenly its grain sorting, the more effective its impact. Thus, with the KSL esstar series, a more economical application is possible compared to unsorted powders.

Our esstar powders are made from native starch, a 100% natural and regrowing raw material. It comes from nature and can easily be returned to it after it has been used as separating agent. It can also remain on the product, especially if it is intended to come into contact with food, as the used starch is a food itself. All relevant certificates are available (e.g. ISEGA, Kosher).

All esstar powders take on electrostatic charge, which facilitates good adhesion to the foil surface. Even better adhesion to non-polar surfaces, such as PE and PP films, can be achieved with coated esstar plus powders, which also have hydrophobic (water-repellent) properties. Depending on film material and application, we recommend the use of esstar 20, 22 or 30 in the regular or coated variant esstar plus.

Please contact us to choose the right esstar powder.

During production, further processing and filling of plastic bags, naturally occurring adhesive forces can lead to problems in these mostly fully automatic processes.

By using high-quality esstar separating powders, these problems can be significantly reduced, while the processing speed is increased and machine downtime can be prevented. We recommend the use of proven KSL esstar 30, a separating powder made from native starch with a very even particle size distribution, which allows a minimal use of powder. In this way, costs can be reduced and unnecessary pollution of the production environment with fine dust is prevented.

Powdering inside or outside?

The bags are usually powdered on the outside. This gives the bags better gliding properties, which means that further processing can run smoothly and therefore faster.

In some cases, it may also be necessary to powder the inside of the bags, which can be done in previous process steps if necessary. The powder coating on the inside of the bag has an antistatic effect and enables the bag to be opened easily and fully automatically when it is filled later on.

The esstar powders consist of native starch and are therefore foodstuffs themselves. As a result, they can be used without hesitation for foil bags, which are later filled with food. Appropriate certificates regarding food grade quality (e.g. ISEGA, Kosher) are available.

Sausage casings are produced as long tubes. When the plastic tube is then laid flat or rolled up, the smooth inner sides of the tube are pressed together, which creates strong adhesive forces. In the following steps, these forces impede an easy opening and thus filling of the sausage casings.

In order to counteract these problems, the inside of the tube is powdered with separating powder of food grade quality. Our powders of the esstar series are natural starch powders that are ideally suited for this purpose and are also certified accordingly. Coarse separating powders such as esstar 30 or esstar 45 are preferably applied here.

Our esstar powders are characterized by their extremely even particle size. Almost every grain contributes effectively to the separation, which significantly reduces the required amount of powder compared to unsorted separation powders. As a result, costs can be saved.