At Glue Machinery Corporation we understand that navigating the world of industrial adhesives can seem daunting, prompting our customers to send us questions about problems they’re working on solving. These problems range from requests for product overviews to needing advice on industry best practices. Rather than keep all this information to ourselves, we thought, “Let’s do our Glue Diligence®!” Therefore, we’re excited to introduce our new monthly content series, Glue Talk: Answers to Your Questions About All Things Adhesive, that will frequently asked questions we’ve received and our responses.
Q: What size hot melt tank should I use for my application?
Typically, we recommend a hot melt tank with twice the hourly melt rate requirement. If the application consumption rate is 5 lbs per hour the minimum size tank is 10 lbs. Some customers want to minimize the interface between the operator and the hot melt machine by purchasing a larger hot melt tank. Automatic fill systems are also available. Sizes range to 1000 lbs.
Q: How fast can I stitch with your hot melt gun?
Hot melt guns can cycle very quickly with standard low to medium viscosity hot melt adhesives. Our most basic pneumatic hot melt gun cycles ON/OFF with an 80 psi air signal from a three way 24VDC solenoid at up to 25 cycles per second. The fastest guns we offer can cycle at up to 100 cycles per second.
Q: What is the highest operating temperature recommended for standard packaging EVA hot melt?
This highest temperature we recommend for this type of hot melt is 375°F. Most EVA hot melts start to degrade at 375°F. The pot life of the hot melt or the time when it starts to degrade can be minimized with fast melting and constant use of the hot melt. Usually higher temperatures are used to bond coated substrates as the adhesive can bite through the coating a little better. With higher temperatures come lower viscosities that allow for more precise extrusion of the melt adhesive without stringing. In some cases the hot melt machinery is too small for the application requiring higher temperatures to meet the melt rate requirement. Where we see hot melts operating at higher temperatures we often look to an optional hot melt that may be better suited for the application and/or improvements in the hot melt machinery that can allow for operation at lower temperatures.
Q: What is Glue Diligence?
For years we have listed our description as the following: Free technical service offered by Glue Machinery Corporation™ to help manufacturers determine the correct adhesive and application method to efficiently produce high quality product at the lowest price.
Actually, Glue Diligence has turned into much, much more than a free testing service. It has created a results oriented culture at Glue Machinery Corporation that includes customer application analysis, thorough evaluation of adhesives and substrates, customer input regarding equipment and adhesive, assembly recommendations, video documentation of testing process and bonding achieved, sample production and finally guarantees regarding the performance of the machinery.
Q: Why do fugitive hot melts stain paper substrates?
Fugitive hot melts stain paper substrates as they have oil in them that gives them the cohesive/removable qualities. This oil can migrate into porous paper substrates. Some fugitive hot melts have more oil than others and the staining can be reduced with the lower oil content. Porous paper substrates tend to be more prone to staining with fugitive hot melts than other less porous materials.
The amount of time the bond is required between the substrates can also have effect on the transfer of oil from the glue into the paper. There are fugitive hot melts with less oil content that effectively bond with reduced staining . The price is typically higher and testing must be performed on the substrates as the bonds can be too strong and tear fiber. Other considerations that must be taking into account regarding fugitive hot melt and staining of substrates are the glue application parameters.
Fugitive hot melt does not like high temperature and/or temperature over time. This tends to exacerbate the release of the oil in the fugitive hot melt.
Hot melt machinery used to apply fugitive adhesive must be well maintained and operated at the lowest possible temperature to minimize degradation. Quality fugitive hot melt, continuous use of the hot melt at the correct temperatures and new hot melt equipment will minimize the staining of substrates.
Q: What features are important in a hot melt rollcoater?
We at Glue Machinery Corporation think we have found the key to producing the highest quality industrial hot melt rollcoaters.
The machines should have the following features:
- Heated Coating Roller and heated tank
- Variable Speed Drive All Steel construction
- Large Drive Motor 240 V high output heating
- Adjustable coating
- Small footprint
- Enclosure around majority of heated machinery
- Two Heated Zones
- Fast heating
- Very slow heating to temperature
These features assure that precise hot melt glue patterns are applied to the bottom of all substrates that pass over the roll. They assure insure that maximum productivity is achieved with the hot melt rollcoater.