APPAREL MANUFACTURING - I 3(1+2)

Lesson 13 : Supporting Materials

Synthetic adhesives

Synthetic adhesives are based on elastomers, thermoplastics, emulsions, and thermosets. Examples of thermosetting adhesives are: epoxy, polyurethane, cyanoacrylate and acrylic polymers.

Application

Applicators of different adhesives are designed according to the adhesive being used and the size of the area to which the adhesive will be applied. The adhesive is applied to either one or both of the materials being bonded. The pieces are aligned and pressure is added to aid in adhesion and rid the bond of air bubbles.

Common ways of applying an adhesive include brushes, rollers, using films or pellets, spray guns and applicator guns (e.g., caulk gun). All of these can be done manually or can be automated into a machine.

Mechanisms of adhesion

Adhesion, the attachment between adhesive and substrate may occur either by mechanical means, in which the adhesive works its way into small pores of the substrate, or by one of several chemical mechanisms. The strength of adhesion depends on many factors, including the means by which it occurs.

1. In some cases an actual chemical bond occurs between adhesive and substrate.
2. In others electrostatic forces, as in static electricity, hold the substances together.
3. A third mechanism involves the Van der Waals forces that develop between molecules.
4. A fourth means involves the moisture-aided diffusion of the glue into the substrate, followed by hardening.