Synthetic leather industry commonly used technical terms
Component A - In the United States, the isocyanate component of the two-component system is often referred to as the A component and may contain a portion of the polyol. Component B is composed of chain extenders and matched polyols. Note: This term is just the opposite in Europe and some countries.
The ratio of the total equivalent of isocyanate in the index to the total equivalent of (hydroxyl + amine) is expressed as a percentage, and the TPU producer uses
Glass transition - As the temperature decreases, the PU gradually loses its elasticity and hardens. In the soft segment Tg, the nature of the PU will change significantly, so that the local movement of molecules to really stop.
Acid value - refers to the trace amount of acid remaining in the polyol. Typically about 0.5% in the polyester diol and about 0.05% or less in the polyether diol. The lower the acid value, the better.
Hydroxyl value - hydroxyl content per unit weight of polyol. (The hydroxyl value corresponds to the molecular weight, from which it is known that the desired NCO content).
