Animal glues are used in rubber compounding to modify the physical properties of the rubber. In particular applications such as textile rollers, cots, and aprons used in weaving cloth, the glue prevents static buildup during weaving, which causes fiber lapping or winding of fibers around rollers. The static electricity is discharged through the rollers, due to the electrolytic properties of the glue and the humidity in the air. Because of their amphoteric electrolytic properties, animal glues are also used as suspending or coagulating agents in rubber-water emulsions.
2. Luggage and Case Covering
Large volumes of compounded animal glue adhesives are used for soft — and hardsided luggage, case, casket, and table pad covering and lining. These are basically hand operations where the glue is applied by roller applicator to the covering or lining material, usually uncoated or coated cloth or leather, and the material is positioned on the piece and glued into place. This is generally followed by riveting or sewing to finish the unit. These products are characterized by good tack to hold the material in place, and long open time to allow movement of the material into final position. For soft-sided luggage, dry film flexibility is also important, to prevent glue cracking. The adhesive should also have a low reducible sulfur content, to minimize tarnishing of metal fittings.