Few Tips for Applying Hot Melt Adhesives

The hot melt adhesives are generally made of the following:

  • They don’t contain any solvents or water.
  • They can easily bond 2 non-porous materials.
  • They are set by heat loss that gives them a fast setting speed.
  • Polymers offer adhesive strength and a certain degree of flexibility.
  • Resins offer the immediate hot-tack of your adhesives.
  • Wax can thin the adhesive for easy applying.
  • Antioxidants can help to preserve the adhesive at higher temperatures.

If you are looking for any hot melt machine then you’ll come across many suppliers, who are also dealing with various textile machineries for weaving, technical textiles, textile finishing, and green technologies, etc.

For optimum usage of your hot melt adhesives, the following are a few tips to remember:

1.     Check the temperature

Ensure that you check and also follow the temperature range recommended for the adhesive that you will use. Never exceed the range of operating temperature of your hot melt. By doing so, you will burn the adhesive that can damage your dispensing equipment. It will then render your hot melt adhesive totally useless.

2.     Clean the substrates

Always clean the substrates that you are bonding. Your hot melt adhesives may bond to dust, and hence, if you are dealing with any dusty substrate, you will end up compromising the integrity of the bond.

While working with metal, make sure that the surface is not greasy or oily. If found so, then clean the surface by using an appropriate solvent before applying the hot melt adhesive.

3.     Check the viscosity

Usually, the viscosity will be related to the hot melt’s temperature. Higher the temperature, higher will be the viscosity. If your hot melt is flowing very slowly, then gradually raise the temperature, however, just make sure that you are staying within the range of recommended operating temperature.

Any normal craft-type of glue gun may run between 250°C to 400°C and when it will get to the right temperature then the flow will be considered as a medium to a little high viscosity. Within 15 seconds it may get harden.

4.     Know about the hot melt adhesive

Make sure that you are familiar with the hot melt adhesive type that you are using. Usually, EVA hot melts will be well-suited for packaging and also wood applications. Polyolefins will be more specialized and are quite a good fit for fabric, foam, and metal. Polyamides usually have very high heat resistance and can often be used in applications like electrical potting and also manufacturing circuit boards.

  • Open time

You will also like to consider open time during the application of an adhesive. The open time of an adhesive refers to the time needed for achieving a serviceable bond. Few factors that can affect open time are:

  • Substrate
  • Temperature
  • Adhesive amount applied
  • Compression

When 2 substrates are bonded together, normally they undergo pressure or compression. Be careful about applying the right compression amount to your substrates for achieving an ideal bond without actually impacting the performance of the substrate.

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