Hotmelt vs Cold glue: Lareka can help you with this sticky decision!

When it comes to packaging chocolate bars, glue is a key element of the wrapping process. The most popular options available on the market are hotmelt, cold glue and sealing systems (though sealing is only for flowpack and the inner layer of dye folded bars). Hotmelt is an adhesive made of thermoplastics that, after heated to a liquid state, is applied to the packaging whereas cold glue is a water-based option that is set on at room temperature.

At Lareka we offer both cold glue and hotmelt for our machines. However, recently we have seen that a considerable amount of chocolate makers opt for a machine equipped with hotmelt rather than one with a cold glue system. Yet, why is that?

To answer this question we have carefully crafted this guide to help you understand the main differences between choosing a Lareka machine equipped with either hot melt or a cold glue system. Despite the fact that both systems can deliver great results, picking the right type of glue can make a big difference on the speed of the wrapping process, the strength of the bond between the materials and the choice of materials (as some materials cannot be processed with cold glue). 

Technical reasons 

Hotmelt 

When equipped with a hotmelt system, the Lareka machine applies one or two small dots of glue (depending on the size of the bar) on the wrapping paper that dry within seconds and creates a strong bond between the materials. As soon as the products come out of the machine, they are ready to go and can immediately be prepared for dispatch. The machine needs only 20 minutes to warm up and then can keep wrapping bars until the work shift is done. 

A great advantage of hotmelt is its versatility, meaning that not only it can be used to glue many different types of materials but also, it is suitable for several kinds of chocolate bars with and without toppings. For instance, hotmelt is the best glue choice for the popular Neapolitan since, due to their relatively small size, they require fast-setting and high-strength bonding. 

The hotmelt system is extremely popular amongst our customers. Approximately, 9 out of 10 customers opt for hotmelt due to its quick bonding time, versatility and easy maintenance. Although you are always free to choose what system best suits your operation, there are several situations in which hotmelt is mandatory: 

1. When the bars have toppings
2. When the bars are wrapped in paper that is thicker than 100 gram/m2 
3. When bars are wrapped in cardboard box
4. With neapolitan size bars

Cold glue

On the other hand, a Lareka machine that uses cold glue is designed with two to four nozzles depending on the dimensions of the bars. After coming out of the machine, the bars need to be stacked properly to make sure that the glue dries well and the packaging does not displace as cold glue dries by evaporating moisture. If not stacked properly, there is a chance that the packaging will ‘spring’ back open due to the natural tension of the paper. 

Furthermore, a cold glue system produces the best packaging results mainly with plain chocolate bars as it requires a flat, smooth and consistent surface to function properly. Toppings such as nuts, cookies and chocolate chips create uneven surfaces and gaps in the bar which can result in weak bond strength, more pressure on the paper and, if not completely dry, packaging popping open. Additionally, cold glue creates a strong bond between paper-based materials but is not suitable for cellulose fiber paper and coated paper. 

Production efficiency 

In production, it is quite normal for our customers to stop for five minutes as they are waiting for the next bars to be wrapped. If using a cold glue system, during that time the glue on the nozzle starts to solidify. Thus, every time they stop, the head of the nozzle needs to be covered with a damp cloth and the residue of glue must be cleaned off before starting to wrap again. With hotmelt, this is not the case as the glue does not solidify over the nozzle and always works properly. 

Throughout the years, we saw many customers who previously chose cold glue upgrading to a hotmelt system. Overall, picking the right glue system is very important as it improves efficiency, reduces downtime, and ensures consistent packaging quality. At Lareka, we help our customers throughout the whole process from choosing the best materials to suggesting what glue system fits their production line best. 

Do you have any questions about hot melt and cold glue systems? 

Feel free to get in touch with us and we’ll help you with this sticky decision!