- Cold Cure
A production method for seat foam, resulting in high resilience (HR) foam. In this process, mold temperatures are typically between 50-70 degrees Celsius, and polyether molecular weights range from 2500-6500. The ISO component can be TDI, TM, or MDI. This process is efficient, energy-saving, and widely used.
- Pump Capacity
This term refers to the stability of the metering pump’s flow output. To verify pump capacity, set the flow rate, shoot 35 times continuously, weigh each shot, and calculate the capacity. This helps determine if the pump requires repair or replacement. Usually, pump capacity is checked every three months.
- Pump Linearity
Describes the correlation between the metering pump’s speed and its output. Typically, five different speeds are selected for flow testing, and the output is measured. Good linearity is indicated if these points form a straight line.
- NBT (New Blending Technology)
A modern mixing technique, NBT involves spraying and mixing one ISO with 2 or 3 groups of POLY materials to produce polyurethane foam. Unlike older methods that only allowed adjustment of the POL/ISO mixing ratio and casting weight, NBT enables adjustments of formula moisture, solids content, index, and casting weight, providing greater process flexibility for different foam densities and hardnesses.
- TPR (Timed Pressure Release)
Also known as venting or pre-venting, TPR typically begins 90-120 seconds after mold closure, with venting lasting about 2 seconds. Early venting can result in tender, tear-prone products, while late venting can lead to stiff, shrink-prone products after demolding.
- Initial Spray
During normal pouring, ISO and POLY nozzles open simultaneously, allowing the materials to mix and react in the chamber. If the nozzles do not open simultaneously, the unreacted material can flow out, causing defects in the foam. For example, if polyether comes out first, the foam will be sticky and wet; if ISO comes out first, the foam will be brittle and thin. Another issue could be softness at the initial pour point due to the component coming out first.
- Foaming Index
The foaming index indicates the reaction ratio between ISO and POL. A foaming index of 100 represents a stoichiometric reaction. The formula is:
Foaming Index = Actual ISO usage/Theoretical ISO usage * 100.
The typical foaming index for seat foam is between 90-105. Higher indices result in harder foam, with an index above 105 making the product brittle, and an index below 85 leading to closed-cell shrinkage.
