Hot Melt News

Erecting and sealing cases, cartons and boxes with hot melt adhesive is standard practice in the packaging industry. This is usually accomplished by spreading hot melt over case flaps in a series of parallel beads. Using smaller parallel beads on close centers bonds much faster than using a large bead or two. These smaller beads also offer a much stronger lamination bond, rather than the less effective point of contact bond.

T Nozzle on High Flow Manual Bead Hotmelt Handgun

“T” nozzles, or spreader nozzles, have been used as a low cost method of channeling hot melt into multiple patterns from one applicator. Hot melt adhesive flows under pressure into this “T” or spreader nozzle and is channeled into a series openings on close centers. The “T” nozzle or spreader nozzle is used with hot melt stick guns, hot melt bulk guns as well as automatic hot melt guns.

T Nozzle on ChampStick400 available from Glue Machinery Corporation

The “T” nozzle is not suitable for precise application requirements, as there can be a tendency for temperature variations within the nozzle. The “T” nozzle is much larger than a standard nozzle, so the adhesive temperature varies as it moves through the nozzle and further from the heat source. This can create poor patterning and hot melt stringing. The use of low viscosity
hot melt will result in better flow from the “T” nozzle.

Frequent and consistent use of the gun and nozzle, will also improve patterning, as the hot melt flow through the nozzle actually heats the nozzle making for more consistent temperatures from gun to substrate.

Contact Pierce Covert at 410.761.2727 to discuss this simple alternative to improving your case sealing operation. Also see: Ergo Erector Basic Case Sealer

Improved efficiency is an overriding concern in today’s competitive environment.  An easy place to start is with adhesive usage.  Most automatic hot melt applications can be adjusted to operate with less hot melt adhesive. When planned and executed properly, adhesive reduction can offer significant long term cost savings.

Before making any changes to your hot melt system or adhesives, you should produce sample blanks with non-compressed hot melt and glued samples for evaluation by your hot melt adhesive and hot melt machinery suppliers.

To make thorough recommendations for your adhesive process, it is important to include the following information with your samples:

• Hot Melt System Temperatures
• Air Pressure Used for the Pump
• Nozzle Tip Orifice Size
• Adhesive Specification Sheet
• Current Consumption per Package
• Type of Hot Melt System Currently in Use
• Speed of Operation
• Frequency of Hot Melt System Maintenance
• Pattern Coverage Requirements.
  To include:
  • Number of Beads
  • Bead Profile
  • Centers Between the Beads

It can also be helpful to have your engineering, maintenance, and production personnel review these same samples. They are often able to provide valuable insight into your adhesive application and consumption process.

Too often, hot melt adhesive is used to compensate for other deficiencies in the production process. Dirty and/or poorly maintained hot melt systems can result in reduced adhesive bond quality. Nozzle cloggage issues can merely be the result of an incorrect orifice size on the nozzles. Another point to consider with regard to potential adhesive waste is hot melt application temperature.If the temperature is too hot, the adhesive is too thin, and this can result in excess amounts of adhesive being dispensed.

The case, carton, corrugated box sealing and erecting industry is one that has seen significant improvements on adhesive savings with the use of professional and in-house adhesive consumption consultation. It is important to note that incorrect compression of the adhesive and substrate on the erector or sealer can affect the sealing capacity of hot melts between substrates.

Be sure to also read our article, “Use Lower Cost Hot Melt” to learn about the benefits of using “Melt on Demand” Hot Melt Tanks and how they too can reduce your production costs.

Contact Glue Machinery Corporation today to discuss your application and how we can improve your adhesive savings.

During the last downturn in the US economy, we were invited to speak at a major hot melt supplier annual sales meeting. We discussed the use of lower cost hot melt adhesives as a cost saving measure for their customers. This was a viable alternative as a result of the “Melt on Demand” technology we provide.

Lower cost adhesives typically have more limited “pot life” than those of higher cost and quality. The “pot life” is the amount of time it takes for hot melt to start degrading when held at application temperature in a melt tank. These “Melt on Demand” hot melt tanks can process these lower cost adhesives because they melt and condition hot melt adhesive at lower temperatures than all other tanks.

The “Melt on Demand” tanks are tall and narrow with a high power melt grid in the bottom. They are specifically designed to melt hot melt as needed, rather than heating the entire tank of hot melt to application temperature. The “Melt on Demand” tank creates a graduated viscosity of the adhesive and it insures that the adhesive is used in a first in – first out order. Other tanks mix the adhesive, presenting an opportunity for the adhesive to exceed its “pot life”. In the standard 20 pound “Melt on Demand” tank, there is a temperature differential of 50 to 100 degrees F between the melt grid on the bottom of the tank and the top of the tank.

In addition to saving cost on adhesive, these “Melt on Demand” tanks help to reduce downtime due to system maintenance, while lowering the need for disposable spare parts, such as nozzles and filters. Finally, “Melt on Demand” tanks can dramatically reduce or eliminate the fuming of hot melt and decrease operator exposure to molten hot melt, providing a safer work place.

In today’s economy we are all looking for effective cost saving measures. The “Melt on Demand” technology provided by Glue Machinery is one way to have an immediate positive impact on your process as well as your bottom line.

Paper Bag Bottom Gluing is done on most bag machines with a glue paste pot containing a roller and a wheel with a rotating glue pad/stamping system. The paste is poured into the pot, transferred onto the wheel, then transferred again to the stamp.  The stamp contacts and then stamps the bag bottom as it comes through the machine, leaving an “I” pattern of glue on the bag bottom.  This pattern is required to insure thorough bonds for all folded substrates. The bag is then closed and stacked for distribution. The water-based adhesive has some initial tack, but the bond occurs mostly as a result of the adhesive being absorbed by the paper.

This method of applying water-based adhesive is accepted as the standard for the paper bag industry, even though it produces significant amounts of defective product, limits the speed of the machinery, all  while being maintenance intensive. Because the water-based glue dries quickly on the glue pad, it is difficult to insure that the quantity of adhesive is consistantly applied to each bag bottom.  Too little glue or too much glue have the same effect — not bonding the bag bottom. In addition, the varied glue patterns can allow excess adhesive to squeeze out and bond bags to each other. Another common problem is that the paste pot has a tendency to sling adhesive, as the adhesive viscosity varies with the wheel rotation.  This slinging has the effect of “Blocking” bags together and creating the need for excessive cleaning and maintenance on the machine.

New technology is available to bond bag bottoms using non-contact hot melt application systems. As the open bag bottom travels through the bag machine, precise dots and lines of hot melt are applied to the bag bottom from fixed high-speed hot melt guns with the patterns on very close centers. The compression of the bag bottom flaps spreads the hot melt adhesive, which quickly sets to form a permanent bond. Fixed high-speed glue guns insure that there is no pattern variability. The precision nozzles simply open and close according to the signal supplied by the variable speed controller and adhesive is vented into beads or dots onto the bag bottom.

The use of this high speed hot melt system was pioneered by bag manufacturers who specialize in plastic, metalized and coated bag material, where water-based adhesives would not work.  These nonporous substrates have more memory than paper substrates, and they are easily bonded by the aggressive hot melt adhesive applied in precise patterns.

The Bag Bottom Hot Melt Gluer does not touch the bag, does not require hourly maintenance, virtually eliminates product defects,and can easily increase the speed of any bag machine.  This system is versatile and can also be used in seaming applications.

Hot Melt adhesive is a viable and preferred alternative for paper bag bottom gluing. It offers significant improvements in product quality, manufacturing processes, and maintenance requirements.

High Speed Hot Melt Retrofit Package for Bag Machinery

Hot Melt bonds all bag substrates for production of wider range of bags

visit Glue Machinery Corporation to discuss your project and how we can improve your ‘bottom’ line today.