Dual density PU shoe technology, as the name implies, is widely used in the manufacture of safety footwear.
If you want to start your PU safety shoe production line or upgrade your existing factory, this is one of the key manufacturing processes you must know about.
What Does “Dual Density” Mean?
In general terms, “dual density”means the shoe sole is made from two different polyurethane (PU) layers, differing in density and purpose.
The upper layer (the actual midsole) is softer and flexible, designed to give comfort, shock absorption and reduce fatigue for long hours of standing and walking.
The bottom layer (the outsole) is harder and tougher, meant for wear, slip resistance and other hard use.
How the Process Works
Both layers are injected and integrally bonded in one operation, using a machine referred to as a double density PU shoe machine.
It’s not just a matter of gluing the two layers together – but a chemical bonding during the moulding of the shoe, which will produce a strong and long term professional adhesion.
Why Dual Density PU Shoes Are Widely Used
In comparison with single density soles/pumps, dual density PU shoes provide greater flexibility of design, comfort and performance characteristics, which is why they feature widely in the construction, oil & gas, mining and other heavy wearable industries.
Key Equipment for Production
In terms of production, equipment needed is made up of:
- A good PU mixing and dosing system
- A good stable rotary injection moulding machine
- Accurate control of variables; temperature, pressure and material ratio.
Stability of all the above onto known product variables will produce bad bonding, bubbles etc.
Manufacturing Considerations
For the manufacturer, the dual density PU shoe gives an obvious extra positioning advantage (high value product – more margin), but on the down side make up of the shoes carries the extra implications of a complete planning solution from factory layout, design of dancing and moulds etc and training for the workforce.
And this is why many buyers prefer a complete turnkey PU production solution of factory planning, equipment and technical support.
Final Thoughts
If you are considering a new entry into the safety shoe market, or looking to upgrade your PU safety shoe production line, then learn about the dual density PU process and about both equipment and plant layout, your product will depend heavily on it in quality terms and long term future viability.
If you would like to discuss your project for actual cost, machine configuration, quantities you would wish to produce, then simply contact us for practical details based on your target market.
