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Do you know the role of wax in EVA hot melt adhesive?

Do you know the role of wax in EVA hot melt adhesive?

2022-05-18

Ethylene vinyl acetate (EVA) hot melt adhesive is the most widely used hot melt adhesive at present. This hot melt adhesive has the characteristics of excellent adhesion, softness, heating fluidity and cold resistance. It is widely used in carton, book bonding, wood laminate production, woodworking edge sealing, non-woven fabric production, etc.

Sainuo EVA wax has good dispersion effect on carbon black and pigment, good light dispersion and high coloring intensity.

PE waxfor hot melt adhesive performance equivalent Sasol H1, Concentrated carbon distribution, concentrated molecular weight distribution, very low thermal weight loss, good early, middle and late stage lubrication performance, excellent late thermal stability, no migration, no precipitation, no odor, meet FDA requirements.

The role of wax in EVA hot melt adhesive is mainly reflected in these aspects:

1. Cohesiveness

Adhesion is one of the most important properties of hot melt adhesive, and there are many influencing factors. The lower the viscosity, the easier it is for the hot melt adhesive to penetrate into the porous substrate, so as to form mechanical bonding. The surface energy of wax is low. When the amount of wax increases, the wettability of hot melt adhesive improves and the adhesion can be increased. Using microcrystalline wax instead of paraffin can improve the adhesion caused by valence bond force, which is due to the low modulus and long setting time of microcrystalline wax hot melt adhesive.

For polar substrates, the use of waxes with polar groups (such as hydroxyl wax or natural wax) can improve the adhesion. The adhesion of hot melt adhesive is affected by the compatibility of the whole adhesive system. Taking wax and EVA as an example, the compatibility between wax and EVA with VA content of 18% - 28% is the best, it is easy to form co crystallization and has good adhesion. However, when VA content is less than 9%, EVA crystallizes before wax and becomes the filler of wax, and the adhesion of glue is very poor.

2. Viscosity and fluidity

The viscosity and fluidity of hot melt adhesive are closely related to the sizing performance. Wax has the greatest impact in this, because wax is the component with the lowest viscosity in hot melt adhesive. Increasing the amount of wax can reduce the viscosity and increase the fluidity.

3. Tensile strength and modulus

Wax with good compatibility with EVA can increase the tensile strength and modulus of hot melt adhesive. If it is incompatible, it will increase the rigidity of adhesive, which is not beneficial to improve the tensile strength. The tensile strength and modulus of hot melt adhesive will be improved by using high crystallization wax or high melting point wax with high n-alkane content.

4. Flexibility

Wax also has a great influence on the flexibility of hot melt adhesive. The flexibility of hot melt adhesive can be increased by using microcrystalline wax instead of paraffin or synthetic wax with narrow distribution instead of ordinary synthetic wax. This is because microcrystalline wax has better flexibility than paraffin, and narrow distribution synthetic wax is more compatible with ethylene segments in EVA.

5. Other aspects

The vitrification temperature Tg of wax is directly related to the low-temperature performance of the adhesive. The increase of the amount of wax can shorten the opening time of hot-melt adhesive, and the setting time can be adjusted by the use of different waxes.

Qingdao Sainuo Chemical Co.,Ltd. We are manufacturer for PE wax, PP wax, OPE wax, EVA wax, PEMA, EBS,Zinc/Calcium Stearate…. Our products have passed the REACH, ROHS, PAHS, FDA testing.

Sainuo rest assured wax, welcome your inquiry!

Website:https://www.sainuowax.com

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