Latex Compounds for Back-Sizing of Woven Carpets

Manufacturer: We are using natural rubber latex compounds for Back Sizing (back coating) of woven carpets. Please suggest some tests we should carry out to ensure consistency in coating quality.

John Woon (Senior Latex Consultant): Your latex compounds should be designed to have the following properties:

1) Constant solid content
2) Consistent viscosity. However it should not be too thixotropic.
3) Should be free from too much bubbles otherwise areas where the bubbles burst would be left uncoated.
4) The surface tension should be low enough to give good wetting property to allow it to penetrate to lock the individual tufts while "strike through" due to too much wicking is prevented.
5) The compound must have sufficient mechanical stability to withstand transportation, mixing and pumping.

I suggest carry out the following tests:

1) Total Solid Content
2) pH
3) Viscosity including measurement of thixotropy
4) MST (Mechanical Stability Time)
5) Coagulum Content
6) Surface Tension