The adhesive industry is no exception, we use terminology that is not always understood by the layman.
On this note we thought it would be a good idea to explain a few of the more commonly used terms (alphabetically) when describing Hot Melt Adhesives and Glue Guns.
Adhesive Failure – Failure resulting from insufficient bond between the adhesive and one or both substrates, demonstrated by adhesive stripping away from the substrates.
Cohesive Failure – Occurs when internal strength of the adhesive is not as great as the forces applied to it, demonstrated by the adhesive remaining bonded to both substrates.
Compression Time – The amount of time required to hold the bond while the hot melt adhesive cures. Compression is very important in achieving good bonds with hot melt adhesives.
Degradation – A change in the chemical structure of a hot melt adhesive, demonstrated by damage to its appearance or physical properties.
Elongation – The percentage increase in length of a material stressed in tension. The higher the percentage the more flexible the adhesive, e.g. Tecbond 260 / Tecbond 261
Encapsulating – Enclosing an article in an envelope of hot melt adhesive.
Glue Backup – Occurs when an operator attempts to extrude adhesive from a glue gun before it has reached the correct molten temperature. The adhesive which has cooled in the nozzle has not reached molten temperature. Consequently adhesive is forced back along the barrel through the gap between the adhesive and the barrel wall by trigger pressure. Can cause serious burns!
Hot Tack – Also known as Molten Tack is a characteristic of hot melt adhesives in that they have holding power even while in the molten state. Especially important when heavy springy substrates are involved. A product with excellent hot tack can greatly reduce compression time. E.g Tecbond 342
Melt-Back – Occurs when glue has been over-softened and is forced back along the barrel of the applicator by trigger pressure. If your glue gun is left on for more than 30 minutes without being used either turn the tool off or dispense a small amount of adhesive, this will help prevent melt-back. Melt-back can cause serious burns!
Open Time – The amount of working time available to make a suitable bond after the hot melt adhesives has been applied. This can be as short as a second or two with a fast setting packaging adhesive, or up to several minutes for some product assembly adhesives. Tecbond glue sticks are categorised as follows: Short: 1-15 seconds / Medium: 15-30 seconds / Long: 30-60 seconds, exceptions are the Spray-Tec semi-pressure sensitive adhesives, these products have an open time of up to 6 minutes, e.g. Tecbond 430
Ring & Ball Softening Point – A method of measuring the temperature at which the adhesive softens, quoted in degrees. Not to be confused with Heat Resistance.
Thermoplastic – A material capable of being liquefied by heat and re-solidifying once cooled.
Viscosity – The measure of the resistance of a fluid to flow. The lower the viscosity figure the thinner the product will be.
The above terms are commonly used by our GlueGunsDirect Team when describing Tecbond and Tec products and the best method of using these products.
If you have come across an adhesive term that you are unsure about, please email: sales@gluegunsdirect.com we will do our best to explain the term and its meaning.
