Custom Fit

Besides price, popularity and presentation of a brand at the point of sale influence a consumer’s buying decision, and the success of a presentation depends heavily on the type of label used. Advertising and promotional activities can hit a wall seconds after consumers spot a badly labeled container. Poorly dressed bottles can also lead to the loss of customers and ready cash for the company.

On the contrary, a well designed and successfully applied label sells. Manufacturers need to understand the existing labeling techniques and the ways labels, labelers, labeling adhesives, containers and peripheral line equipment synergize to achieve business goals.

Modular labelers provide greater flexibility to changes in future market demands. The machines can accommodate cold glue, self-adhesive labels, roll-fed and hotmelt applications easily.

Information that stick

Labels convey information and generate brand popularity. They are the optical highlight of containers. Although it might be easy to tell whether a glass bottle contains milk or soda pop at a glance, it would not be possible with canned foods. A label thus provides information on what consumers are buying.

Up until the 1950s, labels were manually applied to glass containers and cans. This was eventually replaced by semi-automatic and then fully automatic labeling processes. Labeling machines initially processed paper labels and sticking them to cans and glass containers. Water-based cold glue is used later.

Labeling technologies

Plastic containers and fi lms were used at the end of the 1960s. Researchers began experimenting with labeling techniques and adhesives such as the possibility of using cold glue labels on plastic bottles. However, they would be peeled off the containers when they became damp; and film labels applied to containers using cold glue did not dry.

Working through the challenges, the researchers found the hotmelt labeling technique feasible for paper and plastic labels. Existing labeling techniques were later developed into roll-fed labeling for use with paper and plastic labels. Since the early 1990s, these techniques have included sleeve labeling, where plastic film is processed using stretch-sleeve and shrink-sleeve technology.

Companies can now choose between cold glue, hotmelt, roll-fed, and sleeve labeling described below. These labeling techniques differ in processes and capacity. While rotary cold glue machines can label up to 72,000 containers per hour, rotary machines for self-adhesive labels can label up to 45,000 containers per hour. Hotmelt and roll-fed labels can dress up to 50,000 containers per hour, while sleeve labels dress a maximum of 30,000 containers per hour.

Up until the 1950s, labels were applied manually to glass containers and cans. This was eventually replaced by semi-automatic and automatic labeling processes.

• Cold glue labeling

Known also as cut-and-stack labels, paper labels are stored in a label hopper. Each label is extracted from the hopper by means of a gluing segment to which a gluing roller shell has applied the glue. The gluing segment transfers the label to the gripper cylinder that applies the glued side to the container. The label is later brushed on.

Through this technique, a labeling station can apply several labels such as body and neck labels onto containers. Cold glue labeling remains reliable when containers are slightly damp as the glue has no aversion to moisture. Paper labels are easily removed by the bottle washer – which is particularly advantageous with refillable bottles.

• Self-adhesive labeling

Paper or film self-adhesive labels coated with permanent adhesive are peeled off from a label web during labeling. Transparent, self-adhesive plastic film labels are particularly attractive to the eye. With their 'nolabel' look, the container looks as if it has been printed on.

This labeling process uses roll-fed labeling materials. The label is fed to a dispensing edge, where a sharp bend causes the label to peel off the label web onto the bottles. Servomotors coordinate the speed of the moving container with the dispensing speed of the labeler. The labels are later brushed onto the containers.

Self-adhesive labeling does not have format parts for various label sizes. Unlike cold glue labeling, there is no need for contoured gluing palettes or gripper cylinders. The drawback is the high cost of labeling material and the costs for disposing the label web materials.

In the beverage industry, self-adhesive labeling is used primarily for non-refillable glass and plastic bottles since self-adhesive labels are usually extremely difficult to remove in the bottle washing processes used for refillable containers. The only exception are the more expensive wash-off labels that are available in paper and film, which are removed from the bottle in the bottle washer.

• Roll-fed and hotmelt labeling

Roll-fed labeling material such as plastic film is stored in a roll that winds the material around several guide rollers to the labeling station. The labels are cut and transferred to the vacuum drum. The leading and trailing edges of the label are glued by the gluing roller shell and the glued label is placed on the surface of the container. Once the leading edge of the label is fixed to the bottle, the bottle is rotated as the label is brushed on.

Hotmelt is also used to label bottles with paper or plastic labels. In principle, hotmelt labeling is comparable to the roll-fed technique. The main difference is that the labels are fed from a label hopper instead of a roll. Strips or dabs of hotmelt are applied directly to the container, which is then rotated past the label hopper where labels are removed from the magazine. The rotational movement wraps the labels tightly around the bottles, after which a strip of glue neatly sticks the overlapping ends together.

Both systems are used to dress non-refillable plastic and glass bottles, as it is difficult for bottle washers to remove hotmelt from the containers.

• Sleeve labeling

Plastic film is the only labeling material used in this system. There are two sleeve labeling techniques: stretchsleeve and shrink-sleeve labeling. In the stretch-sleeve labeling process, a plastic sleeve fed into the labeling carousel is cut, stretched, and pulled over the container in position. The elastic plastic material causes it to fit snuggly around the container.

While stretch-sleeve labeling is mainly used on refillable plastic bottles, shrink sleeves are used almost exclusively on non-refillable plastic bottles such as contour bottles. The labeling procedure is identical to that of the stretch-sleeve method. Here, the film is not pre-stretched but pulled loosely over the bottle. Unlike stretch sleeves, shrink sleeves are larger than the bottle’s diameter. After fixing the sleeve position, the shrink sleeves are partially shrunk onto the container.

Since the early 1990s, teachniques have included sleeve labeling, where plastic film is processed using stretchsleeve and shrink-sleeve technology.

Buying advice

Plant managers should consider how much flexibility they require of their labeling systems. If a beverage company decides that it requires cold glue labeling for glass bottles in the long term, it would be feasible for it to invest in a labeler with permanently installed cold glue labeling stations for lower investment costs.

On the contrary, modular labelers provide greater flexibility to changes in future market demands. The machines can accommodate cold glue, self-adhesive labels, roll-fed and hotmelt applications easily. KHS’ Innoket SE for example comprises of an infeed table structure and a central labeling carousel. Manufacturers can confi gure the labeling carousel with any combination of wet glue, hotmelt, roll-fed, or self-adhesive labeling stations.

Manufacturers can install a camera-based alignment system that uses images to calculate the angle of rotation of the bottles so that they pass through each labeling station in exact positions. The bottle plate control then successfully puts the value calculated into practice.

However, the more functions a labeler has, the larger and more expensive the machine will be. If two or more labelers can meet specific labeling requirements, it is better than one labeler that offers a full range of options. The company should decide on the best solution based on production requirements and demand.

What does the future hold?

Digital printing could be the next thing to complement or replace classic labeling procedures. Manufacturers can use digital technology to print additional information on labels aimed at specific groups such as conveying personalized messages to loyal customers. Digital printing could be preferred to the classic label among manufacturers, as it would considerably reduce the number of interfaces needed in the labeler.

Remote Diagnostic Service (ReDiS) is another useful tool. On customer’s request, ReDiS is able to offer trouble-free support from KHS headquarters via modern diagnostic services. Should an equipment malfunction occur, users can receive assistance via the ReDiS by accessing the control unit of the faulty line component. ReDiS could also be used as a video recording device to assist machine operators in their questions on the mechanical equipment in the future.

www.khs.com

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Being the right partner

1. The line supplier should understand customer's requirements and make realistic assessments of expectations and existing equipment.

2. The supplier should ensure that the labeler, label, and label adhesive complement one another.

3. The line technology upstream and downstream of the labeler must form a unit.

4. Have close collaboration between the machine supplier, glassworks or plastic bottle manufacturer, label supplier and the manufacturer of the labeling adhesive.

5. Keep abreast of the types of labels available in the market. KHS for example has a database containing practice-based information on label materials, as well as cooperation with external institutes and universities.

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