6.7.2 polyamide (PA) Hotmelts

PA Hotmelts are made from the condensation of dimeric acids and diamines. They are supplied in pellet form and are solid at room temperature. They have high thermal stability, high melting points and good chemical resistance to many compounds, including many common solvents, plasticisers and oils. Compared to other hotmelts, such as EVA and PO, PA hotmelts offer higher creep resistance under load and better flame retardancy and heat stability. Many grades are thermally stable up to 160°C (320°F).31

30) Charles W. Paul, Adhesion Science and Engineering. Elsevier Science, Amsterdam, 2002.

31) Charles R. Frihart, ‘Specific adhesion model for bonding hot-melt polyamides to vinyl,‘ International Journal of Adhesion and Adhesive (2004), Vol 24. 415-422.

Figure 191 Properties of different hotmelts

6.7.3 Polyurethane (PU) Reactive Hotmelts

PU reactive hotmelt (PUR-HM) is another type of 1C PU adhesive. Because PUR-HM has a higher glass transition temperature and a higher crystalline component content than regular 1C PU, it needs to be heated before application. Therefore, the application process has some similarities to hotmelts.

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