Hot melt adhesive particle melt index selection guide: how to match high and low MI values with your application

What is melt index (MI)?

Melt Index (MI) representshot melt adhesiveFlow velocity at specified temperature and pressure, in g/10min. The higher the MI, the better the fluidity of the adhesive solution; The lower the MI, the more viscous the adhesive. The MI value directly affects the coating method, penetration depth, and bonding effect, and is one of the core parameters for selection.

Applicable scenarios for different MI values

Suggestions for practical selection

• The faster the glue line machine speed, the higher the MI – fast coating requires high fluidity
• Choose high MI for bonding porous materials (such as thick cardboard) – the adhesive liquid seeps into the pores to form anchoring
• Adhesive smooth low surface energy materials (laminated paper, BOPP) are selected with low MI – high fluidity makes it difficult to hang on
• Spray coating equipment requires MI ≥ 30, while roller coating equipment can have MI=10-40

All models of Sunlife hot melt adhesive are labeled with MI values, and Guangzhou Sunlife Trading can provide accurate recommendations based on equipment types and material characteristics.

Frequently Asked Questions

• Q: Does the higher the MI, the lower the adhesive strength?
  A: Not necessarily. MI only reflects fluidity, and the adhesive strength depends on the formula and substrate matching. However, extremely high MI adhesive is indeed prone to loss on smooth surfaces, leading to a decrease in strength.
• Q: Do I need to adjust the temperature when changing different MI particles on the same device?
  A: High MI type can reduce 10-15 ° C, while low MI type requires an increase of about 10 ° C to ensure smooth coating.